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Find video protocols related to scientific articles indexed in Pubmed.
Nanocarriers: bioreducible carboxymethyl dextran nanoparticles for tumor-targeted drug delivery (adv. Healthcare mater. 11/2014).
Adv Healthc Mater
PUBLISHED: 11-11-2014
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Bioreducible nanoparticles, composed of hydrophilic carboxymethyl dextran and hydrophobic bile acid, are developed by J. H. Park and co-workers on page 1829 for the site-specific delivery of poorly water-soluble anticancer drugs at the tumor microenvironment.
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Tumor-targeting glycol chitosan nanoparticles as a platform delivery carrier in cancer diagnosis and therapy.
Nanomedicine (Lond)
PUBLISHED: 10-17-2014
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A natural based polymer, chitosan has received widespread attention in drug delivery systems due to its valuable physicochemical and biological characteristics. In particular, hydrophobic moiety-conjugated glycol chitosan can form amphiphilic self-assembled glycol chitosan nanoparticles (GCNPs) and simultaneously encapsulate hydrophobic drug molecules inside their hydrophobic core. This GCNP-based drug delivery systems exhibit excellent tumor-homing efficacy, attributed to the long blood circulation and the enhanced permeability and retention effect; this tumor-targeting drug delivery results in improved therapeutic efficiency. In this review, we describe the requisite properties of GCNPs for cancer therapy as well as imaging for diagnosis, such as their basic characteristics, in vitro delivery efficiency and in vivo tumor-targeting ability.
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Glycol chitosan nanoparticles as specialized cancer therapeutic vehicles: Sequential delivery of doxorubicin and Bcl-2 siRNA.
Sci Rep
PUBLISHED: 06-17-2014
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Conventional chemotherapy is plagued with adverse side effects because cancer treatments are subject to numerous variations, most predominantly from drug resistance. Accordingly, multiple or multistage chemotherapeutic regimens are often performed, combining two or more drugs with orthogonal and possibly synergistic mechanisms. In this respect, glycol chitosan (GC)-based nanoparticles (CNPs) serve as an effective platform vehicle that can encapsulate both chemotherapeutics and siRNA to achieve maximal efficacy by overcoming resistance. Herein, DOX-encapsulated CNPs (DOX-CNPs) or Bcl-2 siRNA-encapsulated CNPs (siRNA-CNPs) exhibited similar physicochemical properties, including size, surface properties and pH sensitive behavior, regardless of the different physical features of DOX and Bcl-2 siRNA. We confirmed that the CNP platform applied to two different types of drugs results in similar in vivo biodistribution and pharmacokinetics, enhancing treatment in a dose-dependent fashion.
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Sustained local delivery of oncolytic short hairpin RNA adenoviruses for treatment of head and neck cancer.
J Gene Med
PUBLISHED: 05-09-2014
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Oncolytic adenovirus (Ad)-mediated gene therapy is a promising approach for suppression of primary tumors. Therapeutic efficacy of Ad-mediated gene therapy has been limited by immunogenicity, rapid dissemination of viral progenies into systemic circulation and short duration of biological activity. Polymeric sustained local delivery can overcome many of these challenges to produce a viable therapy with improved outcomes.
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DNA amplification in neutral liposomes for safe and efficient gene delivery.
ACS Nano
PUBLISHED: 04-28-2014
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In general, traditional gene carriers contain strong cationic charges to efficiently load anionic genes, but this cationic character also leads to destabilization of plasma membranes and causes severe cytotoxicity. Here, we developed a PCR-based nanofactory as a safe gene delivery system. A few template plasmid DNA can be amplified by PCR inside liposomes about 200 nm in diameter, and the quantity of loaded genes highly increased by more than 8.8-fold. The liposome membrane was composed of neutral lipids free from cationic charges. Consequently, this system is nontoxic, unlike other traditional cationic gene carriers. Intense red fluorescent protein (RFP) expression in CHO-K1 cells showed that the amplified genes could be successfully transfected to cells. Animal experiments with the luciferase gene also showed in vivo gene expression by our system without toxicity. We think that this PCR-based nanofactory system can overcome the toxicity problem that is the critical limitation of current gene delivery to clinical application.
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Prediction of antiarthritic drug efficacies by monitoring active matrix metalloproteinase-3 (MMP-3) levels in collagen-induced arthritic mice using the MMP-3 probe.
Mol. Pharm.
PUBLISHED: 04-14-2014
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Active matrix metalloproteinase-3 (MMP-3) is a prognostic marker of rheumatoid arthritis (RA). We recently developed an MMP-3 probe that can specifically detect the active form of MMP-3. The aim of this study was to investigate whether detection and monitoring of active MMP-3 could be useful to predict therapeutic drug responses in a collagen-induced arthritis (CIA) model. During the period of treatment with drugs such as methotrexate (MTX) or infliximab (IFX), MMP-3 mRNA and protein levels were correlated with fluorescence signals in arthritic joint tissues and in the serum of CIA mice. Also, bone volume density and erosion in the knee joints and the paws of CIA mice were measured with microcomputed tomography (micro-CT), X-ray, and histology to confirm drug responses. In joint tissues and serum of CIA mice, strong fluorescence signals induced by the action of active MMP-3 were significantly decreased when drugs were applied. The decrease in RA scores in drug-treated CIA mice led to fluorescence reductions, mainly as a result of down-regulation of MMP-3 mRNA or protein. The micro-CT, X-ray, and histology results clearly showed marked decreases in bone and cartilage destruction, which were consistent with the reduction of fluorescence by down-regulation of active MMP-3 in drug-treated CIA mice. We suggest that the MMP-3 diagnostic kit could be used to detect and monitor the active form of MMP-3 in CIA mice serum during a treatment course and thereby used to predict the drug response or resistance to RA therapies at an earlier stage. We hope that monitoring of active MMP-3 levels in arthritis patients using the MMP-3 diagnostic kit will be a promising tool for drug discovery, drug development, and monitoring of drug responses in RA therapy.
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Proteinticle/gold core/shell nanoparticles for targeted cancer therapy without nanotoxicity.
Adv. Mater. Weinheim
PUBLISHED: 04-03-2014
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PGCS-NPs (40 nm) with excellent photo-thermal activity are developed, on the surface of which affibody peptides with specific affinity for EGFR and many small gold dots (1-3 nm) are densely presented. The IV-injected PGCS-NPs into EGFR-expressing tumor-bearing mice successfully perform targeted and photothermal therapy of cancer. It seems that the small gold dots released from disassembled PGCS-NPs are easily removed and never cause in vivo toxicity problems.
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Nano carriers that enable co-delivery of chemotherapy and RNAi agents for treatment of drug-resistant cancers.
Biotechnol. Adv.
PUBLISHED: 03-30-2014
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Tumor cells exhibit drug resistant phenotypes that decrease the efficacy of chemotherapeutic treatments. The drug resistance has a genetic basis that is caused by an abnormal gene expression. There are several types of drug resistance: efflux pumps reducing the cellular concentration of the drug, alterations in membrane lipids that reduce cellular uptake, increased or altered drug targets, metabolic alteration of the drug, inhibition of apoptosis, repair of the damaged DNA, and alteration of the cell cycle checkpoints (Gottesman et al., 2002; Holohan et al., 2013). siRNA is used to silence the drug resistant phenotype and prevent this drug resistance response. Of the listed types of drug resistance, pump-type resistance (e.g., high expression of ATP-binding cassette transporter proteins such as P-glycoproteins (Pgp; also known as multi-drug resistance protein 1 or MDR1, encoded by the ATP-Binding Cassette Sub-Family B Member 1 (ABCB1) gene)) and apoptosis inhibition (e.g., expression of anti-apoptotic proteins such as Bcl-2) are the most frequently targeted for gene silencing. The co-delivery of siRNA and chemotherapeutic drugs has a synergistic effect, but many of the current projects do not control the drug release from the nanocarrier. This means that the drug payload is released before the drug resistance proteins have degraded and the drug resistance phenotype has been silenced. Current research focuses on cross-linking the carrier's polymers to prevent premature drug release, but these carriers still rely on environmental cues to release the drug payload, and the drug may be released too early. In this review, we studied the release kinetics of siRNA and chemotherapeutic drugs from a broad range of carriers. We also give examples of carriers used to co-deliver siRNA and drugs to drug-resistant tumor cells, and we examine how modifications to the carrier affect the delivery. Lastly, we give our recommendations for the future directions of the co-delivery of siRNA and chemotherapeutic drug treatments.
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Engineered protein nanoparticles for in vivo tumor detection.
Biomaterials
PUBLISHED: 03-21-2014
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Two different protein nanoparticles that are totally different in shape and surface structure, i.e. Escherichia coli DNA-binding protein (eDPS) (spherical, 10 nm) and Thermoplasma acidophilum proteasome (tPTS) (cylindrical, 12 × 15 nm) were engineered for in vivo optical tumor detection: arginine-glycine-aspartic acid (RGD) peptide (CDCRGDCFC) was genetically inserted to the surface of each protein nanoparticle, and also near-infrared fluorescence dye was chemically linked to the surface lysine residues. The specific affinity of RGD for integrin (?v?3) facilitated the uptake of RGD-presenting protein nanoparticles by integrin-expressing tumor cells, and also the protein nanoparticles neither adversely affected cell viability nor induced cell damage. After intravenously injected to tumor-bearing mice, all the protein nanoparticles successfully reached tumor with negligible renal clearance, and then the surface RGD peptides caused more prolonged retention of protein nanoparticles in tumor and accordingly higher fluorescence intensity of tumor image. In particular, the fluorescence of tumor image was more intensive with tPTS than eDPS, which is due presumably to longer in vivo half-life and circulation of tPTS that originates from thermophilic and acidophilic bacterium. Although eDPS and tPTS were used as proof-of-concept in this study, it seems that other protein nanoparticles with different size, shape, and surface structure can be applied to effective in vivo tumor detection.
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Prevention effect of orally active heparin conjugate on cancer-associated thrombosis.
J Control Release
PUBLISHED: 03-20-2014
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Thrombogenesis is a major cause of morbidity and mortality in cancer patients. Prophylaxis with low-molecular-weight heparin (LMWH) is recommended for cancer patients, but requires non-parenteral delivery methods for long-term treatments. In this study, we sought to generate a new oligomeric-bile acid conjugate of LMWH that can be used for oral delivery. We first synthesized a tetramer of deoxycholic acid (tetraDOCA), which was site-specifically conjugated at the end saccharide of LMWH. When LMWH-tetraDOCA conjugate (LHe-tetraD) was orally administered at a dose of 5mg/kg in ICR mice, the maximum anti-factor Xa level was increased up to 0.62±0.05IU/mL without any evidence of liver toxicity, gastrointestinal damage, or thrombocytopenia. The cancer-associated thrombosis was induced in tumor-bearing mice by local heat application, and the fibrin deposition in tumors was evaluated. The oral administration of LHe-tetraD (either a single dose or multiple daily doses for up to 10days) in mice substantially abolished the coagulation-dependent tropism of fibrinogen in the heated tumors and significantly decreased hemorrhage, compared to the mice treated with saline or subcutaneous injection of LMWH. Thus, the anticoagulation effect of oral LHe-tetraD invokes the benefits of oral delivery and promises to provide an effective and convenient treatment for cancer patients at risk of thrombosis.
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Bioreducible carboxymethyl dextran nanoparticles for tumor-targeted drug delivery.
Adv Healthc Mater
PUBLISHED: 03-14-2014
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Bioreducible carboxymethyl dextran (CMD) derivatives are synthesized by the chemical modification of CMD with lithocholic acid (LCA) through a disulfide linkage. The hydrophobic nature of LCA allows the conjugates (CMD-SS-LCAs) to form self-assembled nanoparticles in aqueous conditions. Depending on the degree of LCA substitution, the particle diameters range from 163 to 242 nm. Doxorubicin (DOX), chosen as a model anticancer drug, is effectively encapsulated into the nanoparticles with high loading efficiency (>70%). In vitro optical imaging tests reveal that the fluorescence signal of DOX quenched in the bioreducible nanoparticles is highly recovered in the presence of glutathione (GSH), a tripeptide capable of reducing disulfide bonds in the intracellular compartments. Bioreducible nanoparticles rapidly release DOX when they are incubated with 10 mm GSH, whereas the drug release is greatly retarded in physiological buffer (pH 7.4). DOX-loaded bioreducible nanoparticles exhibit higher toxicity to SCC7 cancer cells than DOX-loaded nanoparticles without the disulfide bond. Confocal laser scanning microscopy observation demonstrate that bioreducible nanoparticles can effectively deliver DOX into the nuclei of SCC7 cells. In vivo biodistribution study indicates that Cy5.5-labeled CMD-SS-LCAs selectively accumulate at tumor sites after systemic administration into tumor-bearing mice. Notably, DOX-loaded bioreducible nanoparticles exhibit higher antitumor efficacy than reduction-insensitive control nanoparticles. Overall, it is evident that bioreducible CMD-SS-LCA nanoparticles are useful as a drug carrier for cancer therapy.
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Effect of HIFU treatment on tumor targeting efficacy of docetaxel-loaded Pluronic nanoparticles.
Colloids Surf B Biointerfaces
PUBLISHED: 03-13-2014
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Numerous studies have been performed to identify the microenvironment of solid tumors, which is responsible for the insufficient delivery of anticancer drugs to tumor cells due to the poorly organized vasculature and the increased interstitial fluid pressure. As a result, the extravasation of convection-dependent agents including NPs is severely limited. Therefore, we have demonstrated the feasibility of targeting an enhancement of docetaxel-loaded Pluronic nanoparticles (NPs) using high-intensity focused ultrasound (HIFU) as an external stimulus-induced clinical system in tumor tissue. The efficient extravasation of NPs into the interior cells in tumor tissue was induced by relatively low HIFU exposure without apparent acute tissue damage. The enhanced targeting of NPs with near-infrared fluorescence dye was observed in tumor-bearing mice with various HIFU exposures. As a result, the greatest accumulation of NPs at the tumor tissue was observed at an HIFU exposure of 20 W/cm(2). However, the tumor tissue above at 20 W/cm(2) appeared to be destroyed and the tumor targetability of NPs was significantly decreased owing to thermal ablation with necrosis, resulting in the destruction of the tumor tissue and the blood vessels. In particular, a cross-sectional view of the tumor tissue verified that the NPs migrated into the middle of the tumor tissue upon HIFU exposure. The preliminary results here demonstrate that HIFU exposure through non-thermal mechanisms can aid with the extravasation of NPs into the interior cells of tumors and increase the therapeutic effect in enhanced and targeted cancer therapy.
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Fluorescent dye labeled iron oxide/silica core/shell nanoparticle as a multimodal imaging probe.
Pharm. Res.
PUBLISHED: 03-11-2014
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To develop an MRI/optical multimodal imaging probe based on dye-conjugated iron oxide/silica core/shell nanoparticle, and investigate the distance-dependent fluorescence quenching through careful control of the distance between the iron oxide core and fluorescent dyes.
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Chemical tumor-targeting of nanoparticles based on metabolic glycoengineering and click chemistry.
ACS Nano
PUBLISHED: 02-20-2014
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Tumor-targeting strategies for nanoparticles have been predominantly based on optimization of physical properties or conjugation with biological ligands. However, their tumor-targeting abilities remain limited and insufficient. Furthermore, traditional biological binding molecules have intrinsic limitations originating from the limited amount of cellular receptors and the heterogeneity of tumor cells. Our two-step in vivo tumor-targeting strategy for nanoparticles is based on metabolic glycoengineering and click chemistry. First, an intravenous injection of precursor-loaded glycol chitosan nanoparticles generates azide groups on tumor tissue specifically by the enhanced permeation and retention (EPR) effect followed by metabolic glycoengineering. These 'receptor-like' chemical groups then enhance the tumor-targeting ability of drug-containing nanoparticles by copper-free click chemistry in vivo during a second intravenous injection. The advantage of this protocol over traditional binding molecules is that there are significantly more binding molecules on the surface of most tumor cells regardless of cell type. The subsequent enhanced tumor-targeting ability can significantly enhance the cancer therapeutic efficacy in animal studies.
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Self-assembled glycol chitosan nanoparticles for disease-specific theranostics.
J Control Release
PUBLISHED: 02-12-2014
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Hydrophobically modified glycol chitosan (hGC) conjugates spontaneously form self-assembled nanoparticles (NPs) in aqueous conditions, and glycol chitosan NPs (CNPs) have been extensively studied for the past few decades. For disease-specific theranostics, CNPs could be simply modified with imaging agents, and the hydrophobic domains of hGC are available for encapsulation of various drugs. Based on the excellent physiochemical and biological properties, CNPs have been investigated for multimodal imaging and target specific drug delivery. In particular, a recent application of CNPs has shown great potential as an efficient theranostic system because the CNPs could be utilized for a disease-specific theranostic delivery system of different imaging agents and therapeutics, simultaneously. Furthermore, various therapeutic agents including chemo-drugs, nucleotides, peptides, and photodynamic chemicals could be simply encapsulated into the CNPs through hydrophobic or charge-charge interactions. Under in vivo conditions, the encapsulated imaging agents and therapeutic drugs have been successfully delivered to targeted diseases. In this article, the overall research progress on CNPs is reviewed from early works. The current challenges of CNPs to overcome in theranostics are also discussed, and continuous studies would provide more opportunities for early diagnosis of diseases and personalized medicine.
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Theranostic nanoparticles for future personalized medicine.
J Control Release
PUBLISHED: 02-11-2014
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The concept of personalized medicine has recently emerged as a promising way to address unmet medical needs. Due to the limitations of standard diagnostic and therapeutic strategies, the disease treatment is moving towards tailored treatment for individual patients, considering the inter-individual variability in therapeutic response. Theranostics, which involves the combination of therapy and diagnostic imaging into a single system, may fulfill the promise of personalized medicine. By integrating molecular imaging functionalities into therapy, theranostic approach could be advantageous in therapy selection, treatment planning, objective response monitoring and follow-up therapy planning based on the specific molecular characteristics of a disease. Although the field of therapy and imaging of its response have been independently developed thus far, developing imaging strategies can be fully exploited to revolutionize the theranostic systems in combination with the therapy modality. In this review, we describe the recent advances in molecular imaging technologies that have been specifically developed to evaluate the therapeutic efficacy for theranostic purposes.
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Tumor-targeting multifunctional nanoparticles for siRNA delivery: recent advances in cancer therapy.
Adv Healthc Mater
PUBLISHED: 01-20-2014
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RNA interference (RNAi) is a naturally occurring regulatory process that controls posttranscriptional gene expression. Small interfering RNA (siRNA), a common form of RNAi-based therapeutics, offers new opportunities for cancer therapy via silencing specific genes, which are associated to cancer progress. However, clinical applications of RNAi-based therapy are still limited due to the easy degradation of siRNA during body circulation and the difficulty in the delivery of siRNA to desired tissues and cells. Thus, there have been many efforts to develop efficient siRNA delivery systems, which protect siRNA from serum nucleases and deliver siRNA to the intracellular region of target cells. Here, the recent advances in siRNA nanocarriers, which possess tumor-targeting ability are reviewed; various nanoparticle systems and their antitumor effects are summarized. The development of multifunctional nanocarriers for theranostics or combinatorial therapy is also discussed.
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Functional transformations of bile acid transporters induced by high-affinity macromolecules.
Sci Rep
PUBLISHED: 01-07-2014
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Apical sodium-dependent bile acid transporters (ASBT) are the intestinal transporters that form intermediate complexes with substrates and its conformational change drives the movement of substrates across the cell membrane. However, membrane-based intestinal transporters are confined to the transport of only small molecular substrates. Here, we propose a new strategy that uses high-affinity binding macromolecular substrates to functionally transform the membrane transporters so that they behave like receptors, ultimately allowing the apical-basal transport of bound macromolecules. Bile acid based macromolecular substrates were synthesized and allowed to interact with ASBT. ASBT/macromolecular substrate complexes were rapidly internalized in vesicles, localized in early endosomes, dissociated and escaped the vesicular transport while binding of cytoplasmic ileal bile acid binding proteins cause exocytosis of macromolecules and prevented entry into lysosomes. This newly found transformation process of ASBT suggests a new transport mechanism that could aid in further utilization of ASBT to mediate oral macromolecular drug delivery.
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Accurate sequential detection of primary tumor and metastatic lymphatics using a temperature-induced phase transition nanoparticulate system.
Int J Nanomedicine
PUBLISHED: 01-01-2014
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Primary tumor and tumor-associated metastatic lymphatics have emerged as new targets for anticancer therapy, given that these are difficult to treat using traditional chemotherapy. In this study, docetaxel-loaded Pluronic nanoparticles with Flamma (FPR-675, fluorescence molecular imaging dye; DTX/FPR-675 Pluronic NPs) were prepared using a temperature-induced phase transition for accurate detection of metastatic lymphatics. Significant accumulation was seen at the primary tumor and in metastatic lymph nodes within a short time. Particle size, maximum drug loading capacity, and drug encapsulation efficiency of the docetaxel-loaded Pluronic NPs were approximately 10.34±4.28 nm, 3.84 wt%, and 94±2.67 wt%, respectively. Lymphatic tracking after local and systemic delivery showed that DTX/FPR-675 Pluronic NPs were more potent in tumor-bearing mice than in normal mice, and excised mouse lymphatics showed stronger near-infrared fluorescence intensity on the tumor-bearing side than on the non-tumor-bearing side at 60 minutes post-injection. In vivo cytotoxicity and efficacy data for the NPs demonstrated that the systemically administered NPs caused little tissue damage and had minimal side effects in terms of slow renal excretion and prolonged circulation in tumor-bearing mice, and rapid renal excretion in non-tumor-bearing mice using an in vivo real-time near-infrared fluorescence imaging system. These results clearly indicate that docetaxel-loaded Pluronic NPs could provide a strategy to achieve effective cancer therapy by simultaneous delivery to primary tumors, tumor lymphatics, and tumor-associated metastatic lymphatics.
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Cell labeling and tracking method without distorted signals by phagocytosis of macrophages.
Theranostics
PUBLISHED: 01-01-2014
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Cell labeling and tracking are important processes in understanding biologic mechanisms and the therapeutic effect of inoculated cells in vivo. Numerous attempts have been made to label and track inoculated cells in vivo; however, these methods have limitations as a result of their biological effects, including secondary phagocytosis of macrophages and genetic modification. Here, we investigated a new cell labeling and tracking strategy based on metabolic glycoengineering and bioorthogonal click chemistry. We first treated cells with tetra-acetylated N-azidoacetyl-D-mannosamine to generate unnatural sialic acids with azide groups on the surface of the target cells. The azide-labeled cells were then transplanted to mouse liver, and dibenzyl cyclooctyne-conjugated Cy5 (DBCO-Cy5) was intravenously injected into mice to chemically bind with the azide groups on the surface of the target cells in vivo for target cell visualization. Unnatural sialic acids with azide groups could be artificially induced on the surface of target cells by glycoengineering. We then tracked the azide groups on the surface of the cells by DBCO-Cy5 in vivo using bioorthogonal click chemistry. Importantly, labeling efficacy was enhanced and false signals by phagocytosis of macrophages were reduced. This strategy will be highly useful for cell labeling and tracking.
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Non-invasive optical imaging of cathepsin B with activatable fluorogenic nanoprobes in various metastatic models.
Biomaterials
PUBLISHED: 11-13-2013
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An increasing number of treatments of metastases rely on diagnostics and imaging these days. The facts that the activity of cathepsin B (CB) is markedly linked to the metastatic process and that CB is found highly expressed in the pericellular regions in this process make CB an attractive target for diagnosing metastases. We have developed a CB-sensitive nanoprobe (CB-CNP) consisting of self-quenched CB-sensitive fluorogenic peptide probes conjugated onto the surface of tumor-targeting glycol chitosan nanoparticles (CNPs). The freshly prepared CB-CNP formed a spherical nanoparticle structure (280 nm in diameter) and the fluorescence intensity of CB-CNP was strongly quenched in physiological condition. However, self-quenched CB-CNP boosted strong fluorescence signals in the presence of CB, not of cathepsin l or cathepsin d, due to the CB-specific cleavage of self-quenched peptide probes. Importantly, the intravenously injected CB-CNP demonstrated the potential to discriminate metastases in vivo in three metastatic mouse models, including 4T1-luc2 liver metastases, RFP-B16F10 lung metastases and HT1080 peritoneal metastases. Indeed, Western blot analysis confirmed that the CB expression of metastases had increased compared to normal organ in these metastatic mouse models. CB-CNPs may be useful for depicting metastases through non-invasive CB molecular imaging.
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Complex adaptive therapeutic strategy (CATS) for cancer.
J Control Release
PUBLISHED: 11-04-2013
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Tumors begin with a single cell, but as each tumor grows and evolves, it becomes a wide collection of clones that display remarkable heterogeneity in phenotypic features, which has posed a big challenge to current targeted anticancer therapy. Intra- and inter-tumoral heterogeneity is attributable in part to genetic mutations but also to adaptation and evolution of tumors to heterogeneity in tumor microenvironments. If tumors are viewed not only as a disease but also as a complex adaptive system (CAS), tumors should be treated as such and a more systemic approach is needed. Some of many tumors therapeutic strategies are discussed here from a view of a tumor as CAS, which can be collectively called a complex adaptive therapeutic strategy (CATS). The central theme of CATS is based on three intermediate concepts: i) disruption of artifacts, ii) disruption of connections, and iii) reprogramming of cancer-immune dynamics. Each strategy presented here is a piece of the puzzle for CATS. Although each piece by itself may be neither novel nor profound, an assembled puzzle could be a novel and innovative cancer therapeutic strategy.
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Tumor-Targeting Transferrin Nanoparticles for Systemic Polymerized siRNA Delivery in Tumor-Bearing Mice.
Bioconjug. Chem.
PUBLISHED: 10-25-2013
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Transferrin (TF) is widely used as a tumor-targeting ligand for the delivery of anticancer drugs because the TF receptor is overexpressed on the surface of various fast-growing cancer cells. In this article, we report on TF nanoparticles as an siRNA delivery carrier for in vivo tumor-specific gene silencing. To produce siRNA carrying TF nanoparticles (NPs), both TF and siRNA were chemically modified with sulfhydryl groups that can build up self-cross-linked siRNA-TF NPs. Self-polymerized 5-end thiol-modified siRNA (poly siRNA, psi) and thiolated transferrin (tTF) were spontaneously cross-linked to form stable NPs (psi-tTF NPs) under optimized conditions, and they could be reversibly degraded to release functional monomeric siRNA molecules under reductive conditions. Receptor-mediated endocytosis of TF induced rapid tumor-cell-specific uptake of the psi-tTF NPs, and the internalized NPs resulted in a downregulation of the target protein in red-fluorescent-protein-expressing melanoma cancer cells (RFP/B16F10) with negligible cytotoxicity. After systemic administration, the psi-tTF NPs showed marked accumulation at the tumor, leading to successful target-gene silencing in vivo. This psi-tTF NP system provided a safe and effective strategy for in vivo systemic siRNA delivery for cancer therapy.
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Hypoxia-responsive polymeric nanoparticles for tumor-targeted drug delivery.
Biomaterials
PUBLISHED: 10-02-2013
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Hypoxia is a condition found in various intractable diseases. Here, we report self-assembled nanoparticles which can selectively release the hydrophobic agents under hypoxic conditions. For the preparation of hypoxia-responsive nanoparticles (HR-NPs), a hydrophobically modified 2-nitroimidazole derivative was conjugated to the backbone of the carboxymethyl dextran (CM-Dex). Doxorubicin (DOX), a model drug, was effectively encapsulated into the HR-NPs. The HR-NPs released DOX in a sustained manner under the normoxic condition (physiological condition), whereas the drug release rate remarkably increased under the hypoxic condition. From in vitro cytotoxicity tests, it was found the DOX-loaded HR-NPs showed higher toxicity to hypoxic cells than to normoxic cells. Microscopic observation showed that the HR-NPs could effectively deliver DOX into SCC7 cells under hypoxic conditions. In vivo biodistribution study demonstrated that HR-NPs were selectively accumulated at the hypoxic tumor tissues. As consequence, drug-loaded HR-NPs exhibited high anti-tumor activity in vivo. Overall, the HR-NPs might have a potential as nanocarriers for drug delivery to treat hypoxia-associated diseases.
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Oligomeric bile acid-mediated oral delivery of low molecular weight heparin.
J Control Release
PUBLISHED: 09-04-2013
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Intestinal transporters are limited to the transport of small molecular substrates. Here, we describe the development of apical sodium-dependent bile acid transporter (ASBT)-targeted high-affinity oligomeric bile acid substrates that mediate the transmembrane transport of low molecular weight heparin (LMWH). Several oligomers of deoxycholic acid (oligoDOCA) were synthesized to investigate the substrate specificity of ASBT. To see the binding of oligoDOCA on the substrate-binding pocket of ASBT, molecular docking was used and the dissociation rate constants (KD) were measured using surface plasmon resonance. The KD for tetrameric DOCA (tetraDOCA) was 50-fold lower than that for monomeric DOCA, because tetraDOCA interacted with several hydrophobic grooves in the substrate-binding pocket of ASBT. The synthesized oligoDOCA compounds were subsequently chemically conjugated to macromolecular LMWH. In vitro, tetraDOCA-conjugated LMWH (LHe-tetraD) had highest selectivity for ASBT during its transport. Orally administered LHe-tetraD showed remarkable systemic anticoagulation activity and high oral bioavailability of 33.5±3.2% and 19.9±2.5% in rats and monkeys, respectively. Notably, LHe-tetraD successfully prevented thrombosis in a rat model of deep vein thrombosis. These results represent a major advancement in ASBT-mediated LMWH delivery and may facilitate administration of many important therapeutic macromolecules through a non-invasive oral route.
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Hyaluronic acid derivative-coated nanohybrid liposomes for cancer imaging and drug delivery.
J Control Release
PUBLISHED: 08-15-2013
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Nanohybrid liposomes coated with amphiphilic hyaluronic acid-ceramide (HACE) was fabricated for targeted delivery of anticancer drug and in vivo cancer imaging. Nanohybrid liposomes including doxorubicin (DOX) and Magnevist, a contrast agent for magnetic resonance (MR) imaging, with 120-130nm mean diameter and a narrow size distribution were developed. DOX release from the developed formulation was improved at acidic pH (pH5.5 and 6.8) versus physiological pH (pH7.4). Cytotoxicity induced by the blank plain liposome was reduced by coating the outer surface of the nanohybrid liposome with HACE. Cellular uptake of DOX from the nanohybrid liposome was enhanced by HA and CD44 receptor interaction, versus the plain liposome. In vivo contrast-enhancing effects revealed that the nanohybrid liposome can be used as a tumor targeting MR imaging probe for cancer diagnosis. In a pharmacokinetic study in rats, in vivo clearance of DOX was decreased in the order DOX solution, plain liposome (F2), and nanohybrid liposome (F3), indicating prolonged circulation of the drug in the blood stream and improved therapeutic efficacy of the nanohybrid liposome (F3). Based on these findings, the nanohybrid liposomal system may be a useful candidate for real-time cancer diagnosis and therapy.
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Self-crosslinked human serum albumin nanocarriers for systemic delivery of polymerized siRNA to tumors.
Biomaterials
PUBLISHED: 06-28-2013
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The safe and effective systemic delivery of siRNA is a prerequisite for the successful development of siRNA-based cancer therapeutics. For the enhanced delivery of siRNA, cationic lipids and polymers have been widely used as siRNA carriers to form electrolyte complexes with anionic siRNA. However, the considerable toxicity of strong cationic-charged molecules hampers their clinical use. In this study, we utilized human serum albumin (HSA), which is the most abundant of the plasma proteins, as a siRNA carrier for systemic tumor-targeted siRNA delivery. Both HSA and siRNA molecules were thiol-introduced to improve the binding affinity for each other. The resulting thiolated HSA (tHSA) and polymerized siRNA (psi) formed stable nanosized complexes (psi-tHSAs) by chemical crosslinking and self-crosslinking. After internalization, the psi-tHSAs showed target gene silencing activity in vitro comparable to conventional Lipofectamine™-siRNA complexes, without remarkable cytotoxicity. After intravenous injection in tumor-bearing mice, psi-tHSAs accumulated specifically at the tumor sites, leading to efficient gene silencing in the tumors in a sequential manner. The therapeutic VEGF siRNA was loaded into psi-tHSAs, which significantly inhibited tumor-related angiogenesis in PC-3 tumor xenografts and resulted in retarding the growth of PC-3 tumors. The results showed that self-crosslinked psi-tHSA nanocarriers might provide a promising approach for the systemic siRNA therapy of various human cancers.
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TNF-? Gene Silencing Using Polymerized siRNA/Thiolated Glycol Chitosan Nanoparticles for Rheumatoid Arthritis.
Mol. Ther.
PUBLISHED: 06-27-2013
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Among various proinflammatory cytokines involved in the pathogenesis of rheumatoid arthritis (RA), tumor necrosis factor (TNF)-? plays a pivotal role in the release of other cytokines and induction of chronic inflammation. Even though siRNA has the therapeutic potential, they have a challenge to be delivered into the target cells because of their poor stability in physiological fluids. Herein, we design a nanocomplex of polymerized siRNA (poly-siRNA) targeting TNF-? with thiolated glycol chitosan (tGC) polymers for the treatment of RA. Poly-siRNA is prepared through self-polymerization of thiol groups at the 5 end of sense and antisense strand of siRNA and encapsulated into tGC polymers, resulting in poly-siRNA-tGC nanoparticles (psi-tGC-NPs) with an average diameter of 370?nm. In the macrophage culture system, psi-tGC-NPs exhibit rapid cellular uptake and excellent in vitro TNF-? gene silencing efficacy. Importantly, psi-tGC-NPs show the high accumulation at the arthritic joint sites in collagen-induced arthritis (CIA) mice. Treatment monitoring data obtained by the matrix metalloproteinase 3-specific nanoprobe and microcomputed tomography show that intravenous injection of psi-tGC-NPs significantly inhibits inflammation and bone erosion in CIA mice, comparable to methotrexate (5?mg/kg). Therefore, the availability of psi-tGC-NP therapy that target specific cytokines may herald new era in the treatment of RA.Molecular Therapy (2013); doi:10.1038/mt.2013.245.
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In vivo fluorescence imaging for cancer diagnosis using receptor-targeted epidermal growth factor-based nanoprobe.
Biomaterials
PUBLISHED: 06-20-2013
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Receptor-targeted imaging is emerging as a promising strategy for diagnosis of human cancer. Herein, we developed an epidermal growth factor-based nanoprobe (EGF-NP) for in vivo optical imaging of epidermal growth factor receptor (EGFR), an important target for cancer imaging. The self-quenched EGF-NP is fabricated by sequentially conjugating a near-infrared (NIR) fluorophore (Cy5.5) and a quencher (BHQ-3) to EGF, a low-molecular weight polypeptide (6.2 kDa), compared to EGFR antibody (150 kDa). The self-quenched EGF-NP presented great specificity to EGFR, and rapidly internalized into the cells, as monitored by time-lapse imaging. Importantly, the self-quenched EGF-NP boosted strong fluorescence signals upon EGFR-targeted uptake into EGFR-expressing cells, followed by lysosomal degradation, as confirmed by lysosomal marker cell imaging. Consistent with cellular results, intravenous injection of EGF-NP into tumor-bearing mice induced strong NIR fluorescence intensity in the target tumor tissue with high specificity against EGFR-expressing cancer cells. Signal accumulation of EGF-NP in tumor was much faster than that of EGFR monoclonal antibody (Cetuximab)-Cy5.5 conjugates due to the rapid clearance from the body and tissue permeability of low-molecular weight EGF. This self-quenched, EGF-based imaging probe can be applied for diagnosis of various cancers.
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Enhanced drug-loading and therapeutic efficacy of hydrotropic oligomer-conjugated glycol chitosan nanoparticles for tumor-targeted paclitaxel delivery.
J Control Release
PUBLISHED: 06-17-2013
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Enhanced drug-loading and therapeutic efficacies are highly essential properties for nanoparticles as tumor-targeting drug carriers. Herein, we developed the glycol chitosan nanoparticles with hydrotropic oligomers (HO-CNPs) as a new tumor targeting drug delivery system. For enhancing drug-loading efficiency of paclitaxel in drug carriers, hydrotropic 2-(4-(vinylbenzyloxy)-N,N-diethylnicotinamide) (VBODENA-COOH) oligomers, that were used for enhancing the aqueous solubility of paclitaxel, were directly conjugated to glycol chitosan polymers. The amphiphilic conjugates readily formed nanoparticle structure (average size=302±22nm) in aqueous condition. Water-insoluble paclitaxel (PTX) was readily encapsulated into HO-CNPs with a high drug-loading amount up to 24.2wt.% (2.4 fold higher than other polymeric nanoparticles) by a simple dialysis method. The PTX encapsulated HO-CNPs (PTX-HO-CNPs; average size=343±12nm) were very stable in aqueous media up to 50days. Also, PTX-HO-CNPs presented rapid cellular uptake and lower cytotoxicity in cell culture system, compared to Cremophor EL/ethanol formulation of PTX. In tumor-bearing mice, the extravasation and accumulation of PTX-HO-CNPs in tumor tissue were precisely observed by intravital fluorescence imaging techniques. Furthermore, PTX-HO-CNPs showed the higher therapeutic efficacy, compared to Abraxane®, a commercialized PTX-formulation. These overall results demonstrate its potential as a new nano-sized PTX carrier for cancer treatment.
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Multilayer nanoparticles for sustained delivery of exenatide to treat type 2 diabetes mellitus.
Biomaterials
PUBLISHED: 06-16-2013
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A method for the sustained delivery of exenatide was proposed using nanoparticles (NPs) with a core/shell structure. The interactions between lipid bilayers and Pluronics were utilized to form various NPs using a layer-by-layer approach. Transmittance electron microscopy and dynamic light scattering were used to examine the morphology of the NPs. The in vitro release pattern was observed as a function of changes in the structure of the NPs, and the structural integrity of exenatide released was examined by SDS-PAGE analysis. Pharmacokinetics and antidiabetic effects were also observed with the structural change of NPs using in vivo animal models. In vitro-in vivo correlation was discussed in relation to manipulation of the NP structures.
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Biocompatible gelatin nanoparticles for tumor-targeted delivery of polymerized siRNA in tumor-bearing mice.
J Control Release
PUBLISHED: 06-08-2013
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Structural modifications of the siRNA backbone improved its physiochemical properties for incorporating in gene carriers without loss of gene-silencing efficacy. These modifications provide a wider variety of choice of vector systems for siRNA delivery. We developed a tumor-targeted siRNA delivery system using polymerized siRNA (poly-siRNA) and natural polymer gelatin. The polymerized siRNA (poly-siRNA) was prepared through self-polymerization of thiol groups at the 5-end of sense and anti-sense strands of siRNA and was encapsulated in the self-assembled thiolated gelatin (tGel) nanoparticles (NPs) with chemical cross-linking. The resulting poly-siRNA-tGel (psi-tGel) nanoparticles (average of 145 nm in diameter) protect siRNA molecules from enzymatic degradation, and can be reversibly reduced to release functional siRNA molecules in reductive conditions. The psi-tGel NPs presented efficient siRNA delivery in red fluorescence protein expressing melanoma cells (RFP/B16F10) to down-regulate target gene expression. In addition, the NPs showed low toxicity at a high transfection dose of 125 ?g/ml psi-tGel NPs, which included 1 ?M of siRNA molecules. In tumor-bearing mice, the psi-tGel NPs showed 2.8 times higher tumor accumulation than the naked poly-siRNA, suggesting tumor-targeted siRNA delivery of psi-tGel NPs. Importantly, the psi-tGel NPs induced effective tumor RFP gene silencing in vivo without remarkable toxicity. The psi-tGel NPs have great potential for a systemic siRNA delivery system for cancer therapy, based on their characteristics of low toxicity, tumor accumulation, and effective siRNA delivery.
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Ischemic brain imaging using fluorescent gold nanoprobes sensitive to reactive oxygen species.
J Control Release
PUBLISHED: 05-30-2013
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Fluorescein-labeled hyaluronic acids (HA) were immobilized on gold nanoparticles for reactive oxygen species (ROS) detection. The efficacy of HA immobilized gold nanoparticles (HHAuNPs) was evaluated in a stroke animal model. The stroke rat model was produced by transient middle cerebral artery occlusion (MCAO), which induced transient ischemia and reperfusion (I/R) in the brain. The increase of ROS in the I/R brain was confirmed by TBARS assay with the brain extracts. For brain imaging, HHAuNPs were injected into the rat brain 1 h before transient MCAO. Five hours after the injection, the rats were sacrificed and the brains were subjected to imaging analysis. The results showed that stronger signals were detected in the I/R brains than in the normal brains. To identify the time window for effective detection of ROS, HHAuNPs were injected into the post-ischemic rat brains at various time points. The results showed that ROS level reached a maximum at 24 h after the transient MCAO. Also, a live imaging study was performed with HHAuNPs in the normal and I/R animals. The results confirmed that ROS level increased in the I/R animal group with time, while the signal was decreased in the normal animal group. Together, our results suggest that HHAuNPs may be useful to monitor ROS level in the ischemic brain and to identify the infarct areas in ischemic brains for the treatment of stroke.
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Non-invasive optical imaging of matrix metalloproteinase activity with albumin-based fluorogenic nanoprobes during angiogenesis in a mouse hindlimb ischemia model.
Biomaterials
PUBLISHED: 05-15-2013
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Matrix metalloproteinase (MMP)-2 and MMP-9 have been known to play the role of essential mediators in angiogenesis. Non-invasive in vivo imaging approach using imaging probes is a potential method of detecting MMP activity in living animals, wherein imaging probes must include the characteristics of non-toxicity, specific targetability, and reasonable signal intensity. Here, we developed MMP-specific and self-quenched human serum albumin (HSA)-based (MMP-HSA) nanoprobes for non-invasive optical imaging of MMP activity during angiogenesis in the mouse hindlimb ischemia model. MMP-specific fluorogenic peptide probes, which were self-quenched with a near-infrared fluorophore and a quencher, were covalently conjugated to HSA (MMP-HSA nanoprobes). MMP-HSA nanoprobes formed stable nanoparticle structures of approximately 36 nm in diameter. Strongly self-quenched MMP-HSA nanoprobes boosted intense fluorescence signals in the presence of MMP-2 and MMP-9. Furthermore, MMP-HSA nanoprobes showed no cytotoxicity in cell culture. Importantly, intravenous injection of MMP-HSA nanoprobes provided longer blood half-life and successful non-invasive optical imaging of MMP activity during angiogenesis in the mouse hindlimb ischemia model. In addition, the MMP activity visualized by MMP-HSA nanoprobes was consistent with the results of zymography, Western blot, and immunohistochemistry. MMP-HSA nanoprobes may be useful for monitoring of the initial process of angiogenesis through non-invasive MMP imaging.
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Dextran sulfate-coated superparamagnetic iron oxide nanoparticles as a contrast agent for atherosclerosis imaging.
Carbohydr Polym
PUBLISHED: 05-14-2013
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The hallmark of atherosclerosis in its early pathogenic process is the overexpression of class A scavenger receptors (SR-A) by activated macrophages. In this study, dextran sulfate-coated superparamagnetic iron oxide nanoparticles (DS-SPIONs), as a magnetic resonance (MR) imaging contrast agent of atherosclerosis, was prepared via the facile co-precipitation method using a versatile double-hydrophilic block copolymer comprising of a DS segment (ligand for SR-A) and a poly(glyclerol methacrylate) segment (SPIONs surface-anchoring unit). The physicochemical properties of the DS-SPIONs were investigated using various instruments. DS-SPIONs exhibited high aqueous stability compared to dextran-coated SPIONs (Dex-SPIONs), which were used as controls. The cellular uptake behaviors of DS-SPIONs and Dex-SPIONs were evaluated using Prussian blue assay. Interestingly, the DS-SPIONs were effectively taken up by activated macrophages compared to Dex-SPIONs. However, the cellular uptake of DS-SPIONs by activated macrophages was remarkably reduced in the presence of free DS. These results suggest that activated macrophages internalize DS-SPIONs via receptor (SR-A)-mediated endocytosis. T2-weighted MR imaging of the cells demonstrated that activated macrophages treated with DS-SPIONs showed a significantly lower signal intensity compared to those treated with Dex-SPIONs. Overall, these results suggest that DS-SPIONs may be utilized as a potential contrast agent for atherosclerosis MR imaging.
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Gadolinium-coordinated elastic nanogels for in vivo tumor targeting and imaging.
Biomaterials
PUBLISHED: 05-07-2013
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Coordination polymer gels have been recognized as promising hybrid nanoplatforms for imaging and therapeutic applications. Here we report functional metal-organic coordinated nanogels (GdNGs) for in vivo tumor imaging, whose non-crystalline and elastic nature allows for long blood circulation, as opposed to the rapid systemic clearance of common nanohybrids with rigid/crystalline frameworks. The deformable structure of GdNGs was constructed by random crosslinking of highly flexible polyethyleneimines (PEI) with gadolinium (Gd(3+)) coordination. The in vitro characterization revealed that GdNGs have elasticity with an apparent Youngs modulus of 3.0 MPa as well as minimal cytotoxicity owing to the tight chelation of Gd(3+) ions. In contrast to common T1-enhancing gadolinium complexes, GdNGs showed the capability of enhancing negative T2 contrast (r2 = 82.6 mm(-1)s(-1)) due to the Gd(3+)-concentrated nanostructure. Systemic administration of fluorescently labeled GdNGs with core and overall hydrodynamic sizes of ~65 and ~160 nm manifested efficient targeting and dual-modality (magnetic resonance/fluorescence) imaging of tumor in a mouse model. The minimal filtration by the reticuloendothelial system (RES) suggests that the structural deformability helps the large colloids circulate in the blood stream for tumor accumulation. The unusual performance of a large Gd(3+)-complexed colloid (minimal RES sequestration and high T2 contrast enhancement) represents the versatile nature of nanoscopic organic-inorganic hybridization for biomedical applications.
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Facile method to radiolabel glycol chitosan nanoparticles with (64)Cu via copper-free click chemistry for MicroPET imaging.
Mol. Pharm.
PUBLISHED: 05-06-2013
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An efficient and straightforward method for radiolabeling nanoparticles is urgently needed to understand the in vivo biodistribution of nanoparticles. Herein, we investigated a facile and highly efficient strategy to prepare radiolabeled glycol chitosan nanoparticles with (64)Cu via a strain-promoted azide-alkyne cycloaddition strategy, which is often referred to as click chemistry. First, the azide (N3) group, which allows for the preparation of radiolabeled nanoparticles by copper-free click chemistry, was incorporated to glycol chitosan nanoparticles (CNPs). Second, the strained cyclooctyne derivative, dibenzyl cyclooctyne (DBCO) conjugated with a 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelator, was synthesized for preparing the preradiolabeled alkyne complex with (64)Cu radionuclide. Following incubation with the (64)Cu-radiolabeled DBCO complex (DBCO-PEG4-Lys-DOTA-(64)Cu with high specific activity, 18.5 GBq/?mol), the azide-functionalized CNPs were radiolabeled successfully with (64)Cu, with a high radiolabeling efficiency and a high radiolabeling yield (>98%). Importantly, the radiolabeling of CNPs by copper-free click chemistry was accomplished within 30 min, with great efficiency in aqueous conditions. In addition, we found that the (64)Cu-radiolabeled CNPs ((64)Cu-CNPs) did not show any significant effect on the physicochemical properties, such as size, zeta potential, or spherical morphology. After (64)Cu-CNPs were intravenously administered to tumor-bearing mice, the real-time, in vivo biodistribution and tumor-targeting ability of (64)Cu-CNPs were quantitatively evaluated by microPET images of tumor-bearing mice. These results demonstrate the benefit of copper-free click chemistry as a facile, preradiolabeling approach to conveniently radiolabel nanoparticles for evaluating the real-time in vivo biodistribution of nanoparticles.
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Conjugated polymer/photochromophore binary nanococktails: bistable photoswitching of near-infrared fluorescence for in vivo imaging.
Adv. Mater. Weinheim
PUBLISHED: 04-29-2013
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Nanoscopic dense integration between solid-state emission and photochromism provides nanoprobes capable of photoswitching of bright NIR fluorescence with high on/off contrast, bistability and improved signal identification, being suitable for imaging applications in autofluorescence-rich in vivo environments.
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Cancer cell-specific photoactivity of pheophorbide a-glycol chitosan nanoparticles for photodynamic therapy in tumor-bearing mice.
Biomaterials
PUBLISHED: 04-05-2013
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We designed a cancer-cell specific photosensitizer nano-carrier by synthesizing pheophorbide a (PheoA) conjugated glycol chitosan (GC) with reducible disulfide bonds (PheoA-ss-GC). The amphiphilic PheoA-ss-GC conjugates self-assembled in aqueous condition to form core-shell structured nanoparticles (PheoA-ss-CNPs) with good colloidal stability and switchable photoactivity. The photoactivity of PheoA-ss-CNPs in an aqueous environment was greatly suppressed by the self-quenching effect, which enabled the PheoA-ss-CNPs to remain photo-inactive and in a quenched state. However, after the cancer cell-specific uptake, the nanoparticular structure instantaneously dissociated by reductive cleavage of the disulfide linkers, followed by an efficient dequenching process. Compared to non-reducible PheoA-conjugated GC-NPs with stable amide linkages (PheoA-CNPs), PheoA-ss-CNPs rapidly restored their photoactivity in response to intracellular reductive conditions, thus presenting higher cytotoxicity with light treatment. In addition, the PheoA-ss-CNPs presented prolonged blood circulation in vivo compared to free PheoA, demonstrating enhanced tumor specific targeting behavior through the enhanced permeation and retention (EPR) effect. The enhanced tumor accumulation of PheoA-ss-CNPs enabled tumor therapeutic efficacy that was more efficient than free PheoA in tumor-bearing mice. Based on the enhanced intracellular release for cytosolic high dose and switchable photoactivity mechanism for reduced side effects, these results suggest that PheoA-ss-CNPs have good potential for photodynamic therapy (PDT) in cancer treatment.
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Bioreducible hyaluronic acid conjugates as siRNA carrier for tumor targeting.
J Control Release
PUBLISHED: 03-24-2013
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The successful clinical translation of siRNA-based therapeutics requires efficient carrier systems that can specifically deliver siRNA within the cytosol of the target cells. Although numerous polymeric nanocarriers forming ionic complexes with siRNA have been investigated for cancer therapy, their poor stability and lack of tumor targetability have impeded their in vivo applications. To surmount these limitations, we synthesized a novel type of biodegradable hyaluronic acid-graft-poly(dimethylaminoethyl methacrylate) (HPD) conjugate that can form complexes with siRNA and be chemically crosslinked via the formation of the disulfide bonds under facile conditions. The crosslinked siRNA-HPD (C-siRNA-HPD) complexes exhibited high stability in a 50% serum solution, as compared to the uncrosslinked siRNA-HPD (U-siRNA-HPD) complexes and free siRNA. Both the C-siRNA-HPD and U-siRNA-HPD complexes were efficiently taken up by the CD44-overexpressing melanoma cells (B16F10), but not by the normal fibroblast cells (NIH3T3). When the RFP-expressing B16F10 cells were treated with the complexes or free siRNA, the C-siRNA-HPD complexes showed the highest decrease in RFP expression. In vivo studies demonstrated the selective accumulation of C-siRNA-HPD complexes at the tumor site after their systemic administration into tumor-bearing mice, resulting in an efficient gene silencing effect. Overall, these results suggest that the HPD conjugate could be used as an efficient carrier for the tumor-targeted delivery of siRNA.
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Hyperacute direct thrombus imaging using computed tomography and gold nanoparticles.
Ann. Neurol.
PUBLISHED: 03-12-2013
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Advancing the understanding and management of thromboembolic stroke requires simple and robust new methods that would be useful for the in vivo assessment of thrombus burden/distribution and for characterizing its evolution in a prompt and quantitative manner.
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Robust PEGylated hyaluronic acid nanoparticles as the carrier of doxorubicin: mineralization and its effect on tumor targetability in vivo.
J Control Release
PUBLISHED: 02-09-2013
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The in vivo stability and tumor targetability of self-assembled polymeric nanoparticles are crucial for effective drug delivery. In this study, to develop biostable nanoparticles with high tumor targetability, poly(ethylene glycol)-conjugated hyaluronic acid nanoparticles (PEG-HANPs) were mineralized through controlled deposition of inorganic calcium and phosphate ions on the nanoparticular shell via a sequential addition method. The resulting nanoparticles (M-PEG-HANPs) had a smaller size (153.7±4.5nm) than bare PEG-HANPs (265.1±9.5nm), implying that mineralization allows the formation of compact nanoparticles. Interestingly, when the mineralized nanoparticles were exposed to acidic buffer conditions (
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Drug delivery by a self-assembled DNA tetrahedron for overcoming drug resistance in breast cancer cells.
Chem. Commun. (Camb.)
PUBLISHED: 02-06-2013
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A DNA tetrahedron is employed for efficient delivery of doxorubicin into drug-resistant breast cancer cells. The drug delivered with the DNA nanoconstruct is considerably cytotoxic, whereas free doxorubicin is virtually non-cytotoxic for the drug-resistant cells. Thus, the DNA tetrahedron, made of the inherently natural and biocompatible material, can be a good candidate for the drug carrier to overcome MDR in cancer cells.
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Self-assembled amphiphilic DNA-cholesterol/DNA-peptide hybrid duplexes with liposome-like structure for doxorubicin delivery.
Biomaterials
PUBLISHED: 01-29-2013
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DNA nanoparticles have been proposed for drug encapsulation and intracellular delivery, but it has remained a challenge to rationally design DNA nanoparticles for delivery of drug to human cancer cells, not to normal cells. In this study, we synthesized an amphiphilic DNA hybrid duplex by using Watson-Crick base pairing and DNA bioconjugation with cholesterol or tLyp-1 tumor-homing peptide. The resulting amphiphilic DNA hybrid duplexes can self-assemble in an aqueous solution into liposome-like nanoparticles (c-DNA-p nanoparticles) with the exposure of tLyp-1 peptides to their outside. As a nanocarrier for doxorubicin, c-DNA-p nanoparticles can efficiently intercalate doxorubicin and also show the pH-dependent complexing/dissociation behaviors with doxorubicin, resulting in release of doxorubicin into cytosol after cell uptake. Moreover, tLyp-1 peptides with cell penetrating properties and specific binding ability for Neuropilin-1 receptors enable doxorubicin-loaded c-DNA-p nanoparticles to be delivered into the target cells through the NRP-1-dependent internalization pathway. Here, we demonstrated the targeted delivery of doxorubicin to MDA-MB231 breast cancer cells, compared to HFF normal cells. These results provide an alternative approach to specifically delivering doxorubicin into targeted cells for cancer therapy as well as controlling drug release under the acidic conditions such as endosomes or lysosomes.
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Photo-crosslinked hyaluronic acid nanoparticles with improved stability for in vivo tumor-targeted drug delivery.
Biomaterials
PUBLISHED: 01-08-2013
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One of the major hurdles of the nanoparticles as drug carriers is the unintended burst release of loaded drugs during blood circulation. To surmount this issue, we developed photo-crosslinked hyaluronic acid nanoparticles (c-HANPs) with improved stability for tumor-targeted drug delivery. They were readily prepared via UV-triggered chemical crosslinking with the acrylate groups in the polymer backbone. The size of c-HANPs was not much different from that of uncrosslinked HANPs. However, c-HANPs exhibited significantly high stability in a physiological buffer and released the loaded drug, paclitaxel (PTX), in a sustained manner. It is noteworthy that the drug release rate from c-HANPs remarkably increased in the presence of hyaluronidase, an enzyme abundant at the intracellular compartments of the tumor cells. It was found from in vitro cellular uptake tests that c-HANPs were rapidly taken up by the tumor cells via the receptor (CD44)-mediated endocytosis, which was not inhibited by photo-crosslinking. In non-invasive animal imaging results, they showed higher tumor-targeting ability than uncrosslinked HANPs because high stability of c-HANPs enabled their long circulation in the body. Owing to the sustained release of the drug and enhanced tumor-targeting ability, c-HANPs showed higher therapeutic efficacy compared to free PTX and uncrosslinked HANPs. These data implied the promising potential of c-HANP as tumor-targeting drug carriers and demonstrated the remarkable effect of the improved stability upon the biodistribution and therapeutic efficacy of drug-loaded nanoparticles.
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Biocompatible Glycol Chitosan-Coated Gold Nanoparticles for Tumor-Targeting CT Imaging.
Pharm. Res.
PUBLISHED: 01-04-2013
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The application of gold nanoparticles (AuNPs) in biomedical field was limited due to the low stability in the biological condition. Herein, to enhance stability and tumor targeting ability of AuNPs, their surface was modified with biocompatible glycol chitosan (GC) and the in vivo biodistribution of GC coated AuNPs (GC-AuNPs) were studied through computed tomography (CT).
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Characterization of partial ligation-induced carotid atherosclerosis model using dual-modality molecular imaging in ApoE knock-out mice.
PLoS ONE
PUBLISHED: 01-01-2013
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Recently, partial ligation of the common carotid artery (CCA) was reported to induce carotid atheromata rapidly in apolipoprotein-E knockout (ApoE(-/-)) mice. We investigated this new atherosclerosis model by using combined matrix-metalloproteinase (MMP) near-infrared fluorescent (NIRF) imaging and macrophage-tracking luciferase imaging.
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Enhancement of the targeting capabilities of the Paclitaxel-loaded pluronic nanoparticles with a glycol chitosan/heparin composite.
Mol. Pharm.
PUBLISHED: 12-23-2011
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An enhancement of tumor-targeting capability was demonstrated with paclitaxel (PTX)-loaded Pluronic nanoparticles (NPs) with immobilized glycol chitosan and heparin. The PTX-loaded Pluronic NPs were prepared as described in our previous report by means of a temperature-induced phase transition in a mixture of Pluronic F-68 and liquid polyethylene glycol (PEG; molecular weight: 400) containing PTX. The liquid PEG is used as the solubilizer of PTX, and Pluronic F-68 is the polymer that encapsulates the PTX. The glycol chitosan and heparin were immobilized on the surface of the Pluronic NPs in an aqueous medium, and a powdery form of the glycol chitosan/heparin immobilized Pluronic NPs (composite NPs) was obtained by freeze-drying. Field emission scanning electron microscopy and a particle size analyzer were used to observe the morphology and size distribution of the prepared NPs. To apply the composite NPs as a delivery system for the model anticancer drug PTX, the release pattern and pharmacokinetic parameters were observed, and the tumor growth was monitored by injecting the composite NPs into the tail veins of tumor-bearing mice. An enhancement of tumor-targeting capability of NPs was verified by using noninvasive live animal imaging technology to observe the time-dependent excretion profile, the in vivo biodistribution, circulation time, and the tumor-targeting capability of composite NPs.
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Multifunctional nanoparticles for multimodal imaging and theragnosis.
Chem Soc Rev
PUBLISHED: 12-21-2011
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Nanomedicine is the biomedical application of nanoscale materials for diagnosis and therapy of disease. Recent advances in nanotechnology and biotechnology have contributed to the development of multifunctional nanoparticles as representative nanomedicine. They were initially developed to enable the target-specific delivery of imaging or therapeutic agents for biomedical applications. Due to their unique features including multifunctionality, large surface area, structural diversity, and long circulation time in blood compared to small molecules, nanoparticles have emerged as attractive preferences for optimized therapy through personalized medicine. Multimodal imaging and theragnosis are the cutting-edge technologies where the advantages of nanoparticles are maximized. Because each imaging modality has its pros and cons, the integration of several imaging agents with different properties into multifunctional nanoparticles allows precise and fast diagnosis of disease through synergetic multimodal imaging. Moreover, nanoparticles are not only used for molecular imaging but also applied to deliver therapeutic agents to the disease site in order to accomplish the simultaneous imaging and therapy called theragnosis. This tutorial review will highlight the recent advances in the development of multifunctional nanoparticles and their biomedical applications to multimodal imaging and theragnosis as nanomedicine.
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Early diagnosis of arthritis in mice with collagen-induced arthritis, using a fluorogenic matrix metalloproteinase 3-specific polymeric probe.
Arthritis Rheum.
PUBLISHED: 12-01-2011
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Early treatment based on an early diagnosis of rheumatoid arthritis (RA) could halt progression of the disease, but early diagnosis is often difficult. Matrix metalloproteinase 3 (MMP-3) is thought to be particularly important in the pathogenesis of RA. The aim of this study was to investigate whether an MMP-3-specific polymeric probe could be used for early diagnosis and for visualizing the progression of arthritis, using a near-infrared fluorescence (NIRF) imaging system.
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Tumor accumulation and antitumor efficacy of docetaxel-loaded core-shell-corona micelles with shell-specific redox-responsive cross-links.
Biomaterials
PUBLISHED: 10-22-2011
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A robust core-shell-corona micelle bearing redox-responsive shell-specific cross-links was evaluated as a carrier of docetaxel (DTX) for cancer therapy. The polymer micelles of poly(ethylene glycol)-b-poly(L-lysine)-b-poly(L-phenylalanine) (PEG-PLys-PPhe) in the aqueous phase provided the three distinct functional domains: the PEG outer corona for prolonged circulation, the PLys middle shell for disulfide cross-linking, and the PPhe inner core for DTX loading. The shell cross-linking was performed by the reaction of disulfide-containing cross-linkers with Lys moieties in the middle shells. The shell cross-linking did not change the micelle size or the spherical morphology. The shell cross-linked micelles exhibited enhanced serum stability. The DTX release from the DTX-loaded disulfide cross-linked micelles (DTX-SSCLM) was facilitated by increasing the concentration of glutathione (GSH). At an intracellular GSH level, DTX release was facilitated due to the reductive cleavage of the disulfide cross-links in the shell domains. The in vivo tissue distribution and tumor accumulation of the DTX-SSCLM that were labeled with a near-infrared fluorescence (NIRF) dye, Cy5.5, were monitored in MDA-MB231 tumor-bearing mice. Non-invasive real-time optical imaging results indicated that the DTX-SSCLM exhibited enhanced tumor specificity due to the prolonged stable circulation in blood and the enhanced permeation and retention (EPR) effect compared with the DTX-loaded non-cross-linked micelles (DTX-NCLM). The DTX-SSCLM exhibited enhanced therapeutic efficacy in tumor-bearing mice compared with free DTX and DTX-NCLM. The domain-specific shell cross-linking that is described in this work may serve as a useful guidance for enhancing the antitumor therapeutic efficacy of various polymer micelles and nano-aggregates.
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Direct thrombus imaging as a means to control the variability of mouse embolic infarct models: the role of optical molecular imaging.
Stroke
PUBLISHED: 10-21-2011
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High experimental variability in mouse embolic stroke models could mask the effects of experimental treatments. We hypothesized that imaging thrombus directly would allow this variability to be controlled.
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Smart nanocarrier based on PEGylated hyaluronic acid for cancer therapy.
ACS Nano
PUBLISHED: 10-11-2011
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Tumor targetability and site-specific drug release of therapeutic nanoparticles are key factors for effective cancer therapy. In this study, poly(ethylene glycol) (PEG)-conjugated hyaluronic acid nanoparticles (P-HA-NPs) were investigated as carriers for anticancer drugs including doxorubicin and camptothecin (CPT). P-HA-NPs were internalized into cancer cells (SCC7 and MDA-MB-231) via receptor-mediated endocytosis, but were rarely taken up by normal fibroblasts (NIH-3T3). During in vitro drug release tests, P-HA-NPs rapidly released drugs when incubated with cancer cells, extracts of tumor tissues, or the enzyme Hyal-1, which is abundant in the intracellular compartments of cancer cells. CPT-loaded P-HA-NPs (CPT-P-HA-NPs) showed dose-dependent cytotoxicity to cancer cells (MDA-MB-231, SCC7, and HCT 116) and significantly lower cytotoxicity against normal fibroblasts (NIH-3T3) than free CPT. Unexpectedly, high concentrations of CPT-P-HA-NPs demonstrated greater cytotoxicity to cancer cells than free CPT. An in vivo biodistribution study indicated that P-HA-NPs selectively accumulated into tumor sites after systemic administration into tumor-bearing mice, primarily due to prolonged circulation in the blood and binding to a receptor (CD44) that was overexpressed on the cancer cells. In addition, when CPT-P-HA-NPs were systemically administrated into tumor-bearing mice, we saw no significant increases in tumor size for at least 35 days, implying high antitumor activity. Overall, P-HA-NPs showed promising potential as a drug carrier for cancer therapy.
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Polyethylene glycol-conjugated hyaluronic acid-ceramide self-assembled nanoparticles for targeted delivery of doxorubicin.
Biomaterials
PUBLISHED: 10-04-2011
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Polyethylene glycol (PEG)-conjugated hyaluronic acid-ceramide (HACE) was synthesized for the preparation of doxorubicin (DOX)-loaded HACE-PEG-based nanoparticles, 160 nm in mean diameter with a negative surface charge. Greater uptake of DOX from these HACE-PEG-based nanoparticles was observed in the CD44 receptor highly expressed SCC7 cell line, compared to results from the CD44-negative cell line, NIH3T3. A strong fluorescent signal was detected in the tumor region upon intravenous injection of cyanine 5.5-labeled nanoparticles into the SCC7 tumor xenograft mice; the extended circulation time of the HACE-PEG-based nanoparticle was also observed. Pharmacokinetic study in rats showed a 73.0% reduction of the in vivo clearance of DOX compared to the control group. The antitumor efficacy of the DOX-loaded HACE-PEG-based nanoparticles was also verified in a tumor xenograft mouse model. DOX was efficiently delivered to the tumor site by active targeting via HA and CD44 receptor interaction and by passive targeting due to its small mean diameter (<200 nm). Moreover, PEGylation resulted in prolonged nanoparticle circulation and reduced DOX clearance rate in an in vivo model. These results therefore indicate that PEGylated HACE nanoparticles represent a promising anticancer drug delivery system for cancer diagnosis and therapy.
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Bioreducible block copolymers based on poly(ethylene glycol) and poly(?-benzyl L-glutamate) for intracellular delivery of camptothecin.
Bioconjug. Chem.
PUBLISHED: 09-22-2011
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Poly(ethylene glycol)-b-poly(?-benzyl L-glutamate)s bearing the disulfide bond (PEG-SS-PBLGs), which is specifically cleavable in intracellular compartments, were prepared via a facile synthetic route as a potential carrier of camptothecin (CPT). Diblock copolymers with different lengths of PBLG were synthesized by ring-opening polymerization of benzyl glutamate N-carboxy anhydride in the presence of a PEG macroinitiator (PEG-SS-NH(2)). Owing to their amphiphilic nature, the copolymers formed spherical micelles in an aqueous condition, and their particle sizes (20-125 nm in diameter) were dependent on the block length of PBLG. Critical micelle concentrations of the copolymers were in the range 0.005-0.065 mg/mL, which decreased as the block length of PBLG increased. CPT, chosen as a model anticancer drug, was effectively encapsulated up to 12 wt % into the hydrophobic core of the micelles by the solvent casting method. It was demonstrated by the in vitro optical imaging technique that the fluorescence signal of doxorubicin, quenched in the PEG-SS-PBLG micelles, was highly recovered in the presence of glutathione (GSH), a tripeptide reducing disulfide bonds in the cytoplasm. The micelles released CPT completely within 20 h under 10 mM GSH, whereas only 40% of CPT was released from the micelles in the absence of GSH. From the in vitro cytotoxicity test, it was found that CPT-loaded PEG-SS-PBLG micelles showed higher toxicity to SCC7 cancer cells than CPT-loaded PEG-b-PBLG micelles without the disulfide bond. Microscopic observation demonstrated that the disulfide-containing micelle could effectively deliver the drug into nuclei of SCC7 cells. These results suggest that PEG-SS-PBLG diblock copolymer is a promising carrier for intracellular delivery of CPT.
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Gas-generating polymeric microspheres for long-term and continuous in vivo ultrasound imaging.
Biomaterials
PUBLISHED: 09-09-2011
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Ultrasound (US) imaging is one of the most common biomedical imaging methods, due to the easy assessment and noninvasive way. For more precise and accurate US imaging, many contrast agents have been developed in a form of microbubbles composed of inner gas and shell materials. However, microbubbles showed undesirable short half-life under acoustic field during US imaging and insufficient in vivo stability in blood flow due to diffusion or bubble destruction. Therefore, the improvement of the half-life and stability of microbubbles under in vivo condition is highly needed for long-term in vivo US imaging. Herein, we developed rationally designed gas-generating polymeric microsphere (GGPM) that can produce microbubbles without encapsulation of gas for long-term and continuous US imaging. The poly(cholesteryl ?-butyrolactone-b-propylene oxide), poly(CB-PO), with carbonate side chains was synthesized as gas-generating polymer by ring-opening polymerization of cholestryl ?-butyrolactone (CB) and propylene oxide (PO). As optimal structure for intense US signal generation, porous GGPMs (p-GGPMs) with the average size about 3-5 ?m were prepared with poly(CB-PO) by double emulsion method. These p-GGPMs generated continuous US signals over 70 min, while the signals from Sonovue(®), a commercial US contrast agent were completely attenuated within 15 min. This long-term signal duration of p-GGPM was also reproduced when they were subcutaneously injected under the skin of mouse. Moreover, as advanced in vivo application, the fine US imaging of heart in rat was enabled by intravenous injection of p-GGPM. Therefore, these overall results showed the great potential of p-GGPM as gas-generating US contrast agent for in vivo biomedical imaging and diagnosis.
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A monitoring method for Atg4 activation in living cells using peptide-conjugated polymeric nanoparticles.
Autophagy
PUBLISHED: 09-01-2011
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To date, several principal methods are presently used to monitor the autophagic process, but they have some potential experimental pitfalls or limitations that make them not applicable to living cells. In order to improve on the currently developed detection methods for autophagy, we report here fluorescent peptide-conjugated polymeric nanoparticles loaded with a lysosome staining dye in their core. The fluorescent peptide is designed to be specifically cleaved by the Atg4 cysteine protease, which plays a crucial role in autophagy activation. In this study, we demonstrate that peptide-conjugated polymeric nanoparticles can be used to visualize Atg4 activity in both cell-free and cell culture systems. The fluorescence imaging of cells incubated with nanoparticles demonstrates that Atg4 activity is activated in the autophagy-induced conditions, but suppressed in the autophagy-inhibited conditions. These results indicate that Atg4 activity is correlated with autophagic flux through its own regulatory pathway. Therefore, our strategy provides an alternative detection method that can clearly distinguish between an "autophagy active" and "autophagy inactive" state in cultured cells. As our nanoparticles are highly cell-permeable and biocompatible, this detection system has general applicability to living cells and can be extended to cell-based screening to evaluate newly developed compounds.
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In vivo targeted delivery of nanoparticles for theranosis.
Acc. Chem. Res.
PUBLISHED: 08-18-2011
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Therapy and diagnosis are two major categories in the clinical treatment of disease. Recently, the word "theranosis" has been created, combining the words to describe the implementation of these two distinct pursuits simultaneously. For successful theranosis, the efficient delivery of imaging agents and drugs is critical to provide sufficient imaging signal or drug concentration in the targeted disease site. To achieve this purpose, biomedical researchers have developed various nanoparticles composed of organic or inorganic materials. However, the targeted delivery of these nanoparticles in animal models and patients remains a difficult hurdle for many researchers, even if they show useful properties in cell culture condition. In this Account, we review our strategies for developing theranostic nanoparticles to accomplish in vivo targeted delivery of imaging agents and drugs. By applying these rational strategies, we achieved fine multimodal imaging and successful therapy. Our first strategy involves physicochemical optimization of nanoparticles for long circulation and an enhanced permeation and retention (EPR) effect. We accomplished this result by testing various materials in mouse models and optimizing the physical properties of the materials with imaging techniques. Through these experiments, we developed a glycol chitosan nanoparticle (CNP), which is suitable for angiogenic diseases, such as cancers, even without an additional targeting moiety. The in vivo mechanism of this particle was examined through rationally designed experiments. In addition, we evaluated and compared the biodistribution and target-site accumulation of bare and drug-loaded nanoparticles. We then focus on the targeting moieties that bind to cell surface receptors. Small peptides were selected as targeting moieties because of their stability, low cost, size, and activity per unit mass. Through phage display screening, the interleukin-4 receptor binding peptide was discovered, and we combined it with our nanoparticles. This product accumulated efficiently in atherosclerotic regions or tumors during both imaging and therapy. We also developed hyaluronic acid nanoparticles that can bind efficiently to the CD44 antigen receptors abundant in many tumor cells. Their delivery mechanism is based on both physicochemical optimization for the EPR effect and receptor-mediated endocytosis by their hyaluronic acid backbone. Finally, we introduce the stimuli-responsive system related to the chemical and biological changes in the target disease site. Considering the relatively low pH in tumors and ischemic sites, we applied pH-sensitive micelle to optical imaging, magnetic resonance imaging, anticancer drug delivery, and photodynamic therapy. In addition, we successfully evaluated the in vivo imaging of enzyme activity at the target site with an enzyme-specific peptide sequence and CNPs. On the basis of these strategies, we were able to develop self-assembled nanoparticles for in vivo targeted delivery, and successful results were obtained with them in animal models for both imaging and therapy. We anticipate that these rational strategies, as well as our nanoparticles, will be applied in both the diagnosis and therapy of many human diseases. These theranostic nanoparticles are expected to greatly contribute to optimized therapy for individual patients as personalized medicine, in the near future.
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Small heat shock protein as a multifunctional scaffold: integrated tumor targeting and caspase imaging within a single cage.
Biomacromolecules
PUBLISHED: 07-11-2011
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Protein cages have the potential to serve as biomaterials for the targeted therapeutic and imaging systems. As an effort to exploit small heat shock protein (Hsp) cages as multifunctional biomaterials, we demonstrate that chemically and genetically modified Hsp cages permeate the cells via cancer cell binding and subsequent endocytic internalization and can image caspase activity in the live cells. Moreover, we report here that these functional Hsp cages can be specifically accumulated to tumor tissues of tumor-bearing mice when administered intravenously through the lateral tail vein. These tumor-targeting properties could be explained by the prolonged in vivo circulation and enhanced permeability and retention (EPR) effect as well as the ligand-mediated binding to cancer cells. Furthermore, when combined with the caspase sensing ability, our Hsp cage allows us to monitor the therapeutic evaluation after anticancer drug treatment by imaging the caspase activity within tumors. Therefore, we demonstrate that the Hsp cages have multifunctional scaffolds amenable to genetic and chemical modifications without loss of the cagelike architecture and can be exploited as biomedical materials including drug or imaging agent carriers.
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Multi-core vesicle nanoparticles based on vesicle fusion for delivery of chemotherapic drugs.
Biomaterials
PUBLISHED: 06-27-2011
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The Pluronic nanoparticles (NPs) composed of Pluronic (F-68) and liquid polyethylene glycol (PEG, molecular wt: 400) containing docetaxel (DTX) were stabilized with the vesicle fusion. When DTX-loaded Pluronic NPs were mixed with vesicles in the aqueous medium, DTX-loaded Pluronic NPs were incorporated into vesicles to form multi-core vesicle NPs. The morphology and size distribution of multi-core vesicle NPs were observed using FE-SEM, cryo-TEM and a particle size analyzer. To apply multi-core vesicle NPs as a delivery system for DTX, a model anti-cancer drug, the release pattern of DTX was observed and the tumor growth was monitored by injecting the DTX-loaded multi-core vesicle NPs into the tail veins of tumor-bearing mice. We also evaluated the time-dependent excretion profile, in vivo biodistribution, circulation time, and tumor targeting capability of multi-core vesicle NPs using a non-invasive live animal imaging technology.
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Self-assembled nanoparticles based on hyaluronic acid-ceramide (HA-CE) and Pluronic® for tumor-targeted delivery of docetaxel.
Biomaterials
PUBLISHED: 06-01-2011
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Hyaluronic acid-ceramide (HA-CE)-based self-assembled nanoparticles were developed for intravenous docetaxel (DCT) delivery. In this study, physicochemical properties, cellular uptake efficiency, and in vivo targeting capability of the nanoparticles developed were investigated. DCT-loaded nanoparticles composed of HA-CE and Pluronic 85 (P85) with a mean diameter of 110-140 nm were prepared and their morphological shapes were assessed using transmission electron microscopy (TEM). DCT release from nanoparticle was enhanced with increasing P85 concentrations in our in vitro model. Blank nanoparticles exhibited low cytotoxicity in U87-MG, MCF-7 and MCF-7/ADR cell lines. From cellular uptake studies, the nanoparticles developed enhanced the intracellular DCT uptake in the CD44-overexpressing cell line (MCF-7). The nanoparticles were shown to be taken up by the HA-CD44 interaction according to DCT and coumarin 6 (C6) cellular uptake studies. The multidrug resistance (MDR)-overcoming effects of DCT-loaded HA-CE/P85-based nanoparticles were also observed in cytotoxicity tests in MCF-7/ADR cells. Following the intravenous injection of DCT-loaded cyanine 5.5 (Cy5.5)-conjugated nanoparticles in MCF-7/ADR tumor-bearing mice, its in vivo targeting for CD44-overexpressing tumors was identified by non-invasive near-infrared (NIR) fluorescence imaging. These results indicate that the HA-CE-based nanoparticles prepared may be a promising anti-cancer drug delivery system through passive and active tumor targeting.
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Heavy-atomic construction of photosensitizer nanoparticles for enhanced photodynamic therapy of cancer.
Small
PUBLISHED: 05-11-2011
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A new type of heavy-atom-affected Pluronic (F-127) nanoparticle (FIC NP) for photodynamic therapy (PDT) is reported. FIC NPs are formulated with biocompatible constituents, and contain densely integrated iodinated aromatic molecules that form a structurally rigid core matrix and stably encapsulate photosensitizers in a monomeric form. Tiny nanoparticles (?10 nm) are prepared by aqueous dispersion of photosensitizer-embedded aromatic nanodomains, which self-assemble by phase separation from the Pluronic melt mixture. By using spectroscopic studies and cellular experiments, the following is demonstrated: 1) enhanced singlet-oxygen generation by means of the intraparticle heavy-atom effect on the embedded photosensitizer, 2) facilitated cell uptake due to the small nanoscopic size as well as the Pluronic surface characteristics, and thereby 3) actual enhancement of PDT efficacy for a human breast-cancer cell line (MDA-MB-231), which validates a photophysically motivated nanoformulation approach toward an advanced photosensitizing nanomedicine.
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Development of MRI/NIRF activatable multimodal imaging probe based on iron oxide nanoparticles.
J Control Release
PUBLISHED: 05-06-2011
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A fabrication method of Cy5.5-MMP substrate and PEG conjugated iron oxide nanoparticles with thin silica coating (PCM-CS) and its potential as an activatable dual imaging probe for tumor imaging is described in this report. PCM-CS showed an intensity-averaged diameter of 43.1 ± 6.3 nm by dynamic light scattering without any noticeable aggregation over 7 days. Fluorescence of Cy5.5 on the surface of nanoparticles was fully quenched and the quenching efficiency was 97.2%. PCM-CS showed protease specific fluorescence recovery in vitro caused from the specific peptide cleavage by MMP-2 and the probe displayed the sensitivity on 0.5 nM or less enzyme concentration. Tumor was successfully visualized by NIRF and MRI in vivo by intravenously injected PCM-CS. NIRF signal of tumor was gradually increased up to 12h post injection and the intensity of tumor was about 3-4 times higher than normal tissue. NIRF signal at MMP-2 inhibitor treated tumor was clearly lower than tumor without inhibitor due to the insufficient peptide cleavage. NIRF signal at excised tumor was 5-10 times stronger than other organs. Noticeable darkening in magnetic resonance image was observed at the tumor region and the image was gradually darkened at 12h post injection of PCM-CS. The maximum signal difference between tumor region and healthy muscle was 34%.
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Glycol chitosan/heparin immobilized iron oxide nanoparticles with a tumor-targeting characteristic for magnetic resonance imaging.
Biomacromolecules
PUBLISHED: 05-03-2011
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We described the preparation of the glycol chitosan/heparin immobilized iron oxide nanoparticles (composite NPs) as a magnetic resonance imaging agent with a tumor-targeting characteristic. The iron oxide nanoseeds used clinically as a magnetic resonance imaging agent were immobilized into the glycol chitosan/heparin network to form the composite NPs. To induce the ionic interaction between the iron oxide nanoseeds and glycol chitosan, gold was deposited on the surface of iron oxide nanoseeds. After the immobilization of gold-deposited iron oxide NPs into the glycol chitosan network, the NPs were stabilized with heparin based on the ionic interaction between cationic glycol chitosan and anionic heparin. FE-SEM (field emission-scanning electron microscopy) and a particle size analyzer were used to observe the formation of the stabilized composite NPs, and a Jobin-Yvon Ultima-C inductively coupled plasma-atomic emission spectrometer (ICP-AES) was used to measure the contents (%) of formed iron oxide nanoseeds as a function of reaction temperature and formed gold deposited on the iron oxide nanoparticles. We also evaluated the time-dependent excretion profile, in vivo biodistribution, circulation time, and tumor-targeting ability of the composite NPs using a noninvasive NIR fluorescence imaging technology. To observe the MRI contrast characteristic, the composite NPs were injected into the tail veins of tumor-bearing mice to demonstrate their selective tumoral distribution. The MR images were collected with conventional T(2)-weighted spin echo acquisition parameters.
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Comparative study of photosensitizer loaded and conjugated glycol chitosan nanoparticles for cancer therapy.
J Control Release
PUBLISHED: 03-23-2011
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This study reports that tumor-targeting glycol chitosan nanoparticles with physically loaded and chemically conjugated photosensitizers can be used in photodynamic therapy (PDT). First, the hydrophobic photosensitizer, chlorin e6 (Ce6), was physically loaded onto the hydrophobically-modified glycol chitosan nanoparticles (HGC), which were prepared by self-assembling amphiphilic glycol chitosan-5?-cholanic acid conjugates under aqueous conditions. Second, the Ce6s were chemically conjugated to the glycol chitosan polymers, resulting in amphiphilic glycol chitosan-Ce6 conjugates that formed self-assembled nanoparticles in aqueous condition. Both Ce6-loaded glycol chitosan nanoparticles (HGC-Ce6) and Ce6-conjugated chitosan nanoparticles (GC-Ce6) had similar average diameters of 300 to 350 nm, a similar in vitro singlet oxygen generation efficacy under buffer conditions, and a rapid cellular uptake profile in the cell culture system. However, compared to GC-Ce6, HGC-Ce6 showed a burst of drug release in vitro, whereby 65% of physically loaded drugs were rapidly released from the particles within 6.5h in the buffer condition. When injected through the tail vein into tumor bearing mice, HGC-Ce6 did not accumulate efficiently in tumor tissue, reflecting the burst in the release of the physically loaded drug, while GC-Ce6 showed a prolonged circulation profile and a more efficient tumor accumulation, which resulted in high therapeutic efficacy. These comparative studies with drug-loaded and drug-conjugated nanoparticles showed that the photosensitizer-conjugated glycol chitosan nanoparticles with excellent tumor targeting properties have potential for PDT in cancer treatment.
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Real-time and non-invasive optical imaging of tumor-targeting glycol chitosan nanoparticles in various tumor models.
Biomaterials
PUBLISHED: 03-17-2011
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Recently, various nanoparticle systems have been developed for tumor-targeted delivery of imaging agents or drugs. However, large amount of them still have insufficient tumor accumulation and this limits their further clinical applications. Moreover, the in vivo characteristics of nanoparticles have been largely unknown, because there are few proper technologies to achieve the direct and non-invasive characterization of nanoparticles in live animals. In this paper, we determined the key factors of nanoparticles for in vivo tumor-targeting using our glycol chitosan nanoparticles (CNPs) which have proved their tumor-targeting ability in many previous papers. For this study, CNPs were labeled with near-infrared fluorescence (NIRF) dye, Cy5.5 for in vivo analysis by non-invasive optical imaging techniques. With these Cy5.5-CNPs, the factors such as in vitro/in vivo stability, deformability, and rapid uptake into target tumor cells and their effects on in vivo tumor-targeting were evaluated in various tumor-bearing mice models. In flank tumor models, Cy5.5-CNPs were selectively localized in tumor tissue than other organs, and the real-time intravascular tracking of CNPs proved the enhanced permeation and retention (EPR) effect of nanoparticles in tumor vasculature. Importantly, tumor-targeting CNPs showed an excellent tumor-specificity in brain tumors, liver tumors, and metastasis tumor models, indicating their great potential in both cancer imaging and therapy.
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In situ dose amplification by apoptosis-targeted drug delivery.
J Control Release
PUBLISHED: 03-15-2011
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When tumor cells undergo apoptosis in response to chemotherapy, the levels of apoptotic biomarkers such as histone H1 are increased at the tumor. This would amplify in situ homing signals and thus drug delivery by apoptosis-targeted drugs. To examine this possibility, we prepared apoptosis-targeted liposomes containing doxorubicin by labeling them with the CQRPPR peptide (ApoPep-1) that recognizes apoptotic cells by binding to histone H1. ApoPep-1-labeled liposomes, but not folate-labeled liposomes, inhibited tumor growth in mice more efficiently than untargeted liposomes, although in vitro cytotoxicities of those liposomes were similar. Fluorescence imaging signals at tumor were increased by the homing of ApoPep-1-labeled, fluorescent liposomes, which was correlated with the increase of apoptosis and the amount of doxorubicin at the tumor and, conversely, with the decrease of tumor volume. These results demonstrate that the apoptosis-targeted drug delivery enables in situ dose amplification and, when combined with imaging of apoptosis, provides a real-time monitoring of treatment response for cancer theragnosis.
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Application of near-infrared fluorescence imaging using a polymeric nanoparticle-based probe for the diagnosis and therapeutic monitoring of colon cancer.
Dig. Dis. Sci.
PUBLISHED: 03-15-2011
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Early and accurate detection of adenomatous colonic polyps is a major concern in the prevention of colon cancer. Near-infrared fluorescence (NIRF) imaging with optical probes targeting specific peptides enables the noninvasive visualization and characterization of lesions. Matrix metalloproteinases (MMPs) are known to play an important role in tumorigenesis and tumor progression.
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Molecular targeting of atherosclerotic plaques by a stabilin-2-specific peptide ligand.
J Control Release
PUBLISHED: 03-03-2011
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Many cells, including macrophages, accumulate in atherosclerotic lesions, destabilizing plaques and driving plaque disruption. Therefore, macrophages serve as useful targets for atherosclerosis treatment and imaging. Stabilin-2 is a transmembrane protein expressed predominantly in macrophages and endothelial cells. In the present study, we found that stabilin-2 was widely expressed in atherosclerotic plaques than in normal vessel walls, and was present not only in macrophages but also in endothelial and smooth muscle cells in plaques. We used phage display technology to identify peptides that specifically bound to stabilin-2. After four rounds of selection, the most commonly isolated peptide had the sequence CRTLTVRKC, and was named S2P. We confirmed that this peptide specifically bound to stabilin-2-expressing cells in vitro and sinus endothelial cells in the spleen and lymph nodes in vivo. A FITC-conjugated synthetic CRTLTVRKC peptide was shown to home to atherosclerotic plaques in Ldlr-/- mice and to co-localize with endothelial cells, macrophages, and smooth muscle cells in such plaques. S2P conjugated to hydrophobically modified glycol chitosan nanoparticles was efficiently delivered to atherosclerotic plaques. These results show that the CRLTLTVRKC peptide homes to plaques by targeting stabilin-2; the peptide shows promise as a drug delivery moiety for, and an aid to molecular imaging of, atherosclerosis and other inflammatory diseases.
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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.