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Find video protocols related to scientific articles indexed in Pubmed.
National Survey of US Oncologists' Knowledge, Attitudes, and Practice Patterns Regarding Herb and Supplement Use by Patients With Cancer.
J. Clin. Oncol.
PUBLISHED: 11-19-2014
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Patients with cancer commonly use complementary and alternative medicine, including herbs and supplements (HS), during cancer treatment. This national survey explored oncologists' knowledge, attitudes, and practice patterns regarding HS use by their patients.
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The Stability of G6PD Is Affected by Mutations with Different Clinical Phenotypes.
Int J Mol Sci
PUBLISHED: 10-04-2014
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Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzyme deficiency worldwide, causing a wide spectrum of conditions with severity classified from the mildest (Class IV) to the most severe (Class I). To correlate mutation sites in the G6PD with the resulting phenotypes, we studied four naturally occurring G6PD variants: Yucatan, Nashville, Valladolid and Mexico City. For this purpose, we developed a successful over-expression method that constitutes an easier and more precise method for obtaining and characterizing these enzymes. The kcat (catalytic constant) of all the studied variants was lower than in the wild-type. The structural rigidity might be the cause and the most evident consequence of the mutations is their impact on protein stability and folding, as can be observed from the protein yield, the T50 (temperature where 50% of its original activity is retained) values, and differences on hydrophobic regions. The mutations corresponding to more severe phenotypes are related to the structural NADP+ region. This was clearly observed for the Classes III and II variants, which became more thermostable with increasing NADP+, whereas the Class I variants remained thermolabile. The mutations produce repulsive electric charges that, in the case of the Yucatan variant, promote increased disorder of the C-terminus and consequently affect the binding of NADP+, leading to enzyme instability.
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Therapeutic Silencing of KRAS using Systemically Delivered siRNAs.
Mol. Cancer Ther.
PUBLISHED: 10-03-2014
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Despite being amongst the most common oncogenes in human cancer, to date there are no effective clinical options for inhibiting KRAS activity. We investigated whether systemically delivered KRAS siRNAs have therapeutic potential in KRAS mutated cancer models. We identified KRAS siRNA sequences with notable potency in knocking-down KRAS expression. Using lung and colon adenocarcinoma cell lines, we assessed anti-proliferative effects of KRAS silencing in vitro. For in vivo experiments, we used a nano-liposomal delivery platform, DOPC, for systemic delivery of siRNAs. Various lung and colon cancer models were utilized to determine efficacy of systemic KRAS siRNA based on tumor growth, development of metastasis and down-stream signaling. KRAS siRNA sequences induced >90% knock-down of KRAS expression, significantly reducing viability in mutant cell lines. In the lung cancer model, KRAS siRNA treatment demonstrated significant reductions in primary tumor growth and distant metastatic disease, while the addition of CDDP was not additive. Significant reductions in Ki-67 indices were seen in all treatment groups, while significant increases in caspase-3 activity was only seen in the CDDP treatment groups. In the colon cancer model, KRAS siRNA reduced tumor KRAS and pERK expression. KRAS siRNAs significantly reduced HCP1 subcutaneous tumor growth, as well as outgrowth of liver metastases. Our studies demonstrate a proof-of-concept approach to therapeutic KRAS targeting using nanoparticle delivery of siRNA. This study highlights the potential translational impact of therapeutic RNA interference, which may have broad applications in oncology, especially for traditional "undruggable" targets.
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Giardial Triosephosphate Isomerase as Possible Target of the Cytotoxic Effect of Omeprazole in Giardia lamblia.
Antimicrob. Agents Chemother.
PUBLISHED: 09-15-2014
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Giardiasis is highly prevalent in the developing world, and treatment failures with the standard drugs are common. This work deals with the proposal of omeprazole as a novel antigiardial drug, focusing on a giardial glycolytic enzyme used to follow the cytotoxic effect at the molecular level. We used recombinant technology and enzyme inactivation to demonstrate the capacity of omeprazole to inactivate giardial triosephosphate isomerase, with no adverse effects on its human counterpart. To establish the specific target in the enzyme, we used single mutants of every cysteine residue in triosephosphate isomerase. The effect on cellular triosephosphate isomerase was evaluated by following the remnant enzyme activity on trophozoites treated with omeprazole. The interaction of omeprazole with giardial proteins was analyzed by fluorescence spectroscopy. The susceptibility to omeprazole of drug-susceptible and drug-resistant strains of Giardia lamblia was evaluated to demonstrate its potential as a novel antigiardial drug. Our results demonstrate that omeprazole inhibits giardial triosephosphate isomerase in a species-specific manner through interaction with cysteine at position 222. Omeprazole enters the cytoplasmic compartment of the trophozoites and inhibits cellular triosephosphate isomerase activity in a dose-dependent manner. Such inhibition takes place concomitantly with the cytotoxic effect caused by omeprazole on trophozoites. G. lamblia triosephosphate isomerase (GlTIM) is a cytoplasmic protein which can help analyses of how omeprazole works against the proteins of this parasite and in the effort to understand its mechanism of cytotoxicity. Our results demonstrate the mechanism of giardial triosephosphate isomerase inhibition by omeprazole and show that this drug is effective in vitro against drug-resistant and drug-susceptible strains of G. lamblia.
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Bisphosphonates inhibit stellate cell activity and enhance antitumor effects of nanoparticle albumin-bound Paclitaxel in pancreatic ductal adenocarcinoma.
Mol. Cancer Ther.
PUBLISHED: 09-05-2014
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Pancreatic stellate cells (PSC) have been recognized as the principal cells responsible for the production of fibrosis in pancreatic ductal adenocarcinoma (PDAC). Recently, PSCs have been noted to share characteristics with cells of monocyte-macrophage lineage (MML cells). Thus, we tested whether PSCs could be targeted with the nitrogen-containing bisphosphonates (NBP; pamidronate or zoledronic acid), which are potent MML cell inhibitors. In addition, we tested NBPs treatment combination with nanoparticle albumin-bound paclitaxel (nab-paclitaxel) to enhance antitumor activity. In vitro, we observed that PSCs possess ?-naphthyl butyrate esterase (ANBE) enzyme activity, a specific marker of MML cells. Moreover, NBPs inhibited PSCs proliferation, activation, release of macrophage chemoattractant protein-1 (MCP-1), and type I collagen expression. NBPs also induced PSCs apoptosis and cell-cycle arrest in the G1 phase. In vivo, NBPs inactivated PSCs; reduced fibrosis; inhibited tumor volume, tumor weight, peritoneal dissemination, angiogenesis, and cell proliferation; and increased apoptosis in an orthotopic murine model of PDAC. These in vivo antitumor effects were enhanced when NBPs were combined with nab-paclitaxel but not gemcitabine. Our study suggests that targeting PSCs and tumor cells with NBPs in combination with nab-paclitaxel may be a novel therapeutic approach to PDAC. Mol Cancer Ther; 13(11); 2583-94. ©2014 AACR.
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MiR-506 inhibits multiple targets in the epithelial-to-mesenchymal transition network and is associated with good prognosis in epithelial ovarian cancer.
J. Pathol.
PUBLISHED: 07-03-2014
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Extensive investigations have shown that miRNAs are important regulators of epithelial-to-mesenchymal transition (EMT), mainly targeting the transcriptional repressors of E-cadherin (E-cad). Less is known about the post-transcriptional regulation of vimentin or N-cadherin (N-cad) in EMT. Our previous study identified miR-506 as a key EMT inhibitor through directly targeting the E-cad transcriptional repressor SNAI2. In this study, we provide evidence that miR-506 simultaneously suppresses vimentin and N-cad. The knockdown of vimentin using siRNA reversed EMT, suppressed cell migration and invasion, and increased E-cad expression on the cell membrane in epithelial ovarian cancer (EOC) cells. In a set of tissue microarrays that included 204 EOCs of all major subtypes (eg serous, endometrioid, clear cell, and mucinous), miR-506 was positively correlated with E-cad and negatively correlated with vimentin and N-cad in all subtypes of EOC. A high level of miR-506 was positively associated with early FIGO stage and longer survival in EOC. Introduction of miR-506, mediated by nanoparticle delivery, in EOC orthotopic mouse models resulted in decreased vimentin, N-cad, and SNAI2 expression and increased E-cad expression; it also suppressed the dissemination of EOC cells. Thus, miR-506 represents a new class of miRNA that regulates both E-cad and vimentin/N-cad in the suppression of EMT and metastasis. Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Magnetographic array for the capture and enumeration of single cells and cell pairs.
Biomicrofluidics
PUBLISHED: 07-01-2014
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We present a simple microchip device consisting of an overlaid pattern of micromagnets and microwells capable of capturing magnetically labeled cells into well-defined compartments (with accuracies >95%). Its flexible design permits the programmable deposition of single cells for their direct enumeration and pairs of cells for the detailed analysis of cell-cell interactions. This cell arraying device requires no external power and can be operated solely with permanent magnets. Large scale image analysis of cells captured in this array can yield valuable information (e.g., regarding various immune parameters such as the CD4:CD8 ratio) in a miniaturized and portable platform.
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RNAi therapies: drugging the undruggable.
Sci Transl Med
PUBLISHED: 06-13-2014
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RNA interference (RNAi) therapy is a rapidly emerging platform for personalized cancer treatment. Recent advances in small interfering RNA delivery and target selection provide unprecedented opportunities for clinical translation. Here, we discuss these advances and present strategies for making RNAi-based therapy a viable part of cancer management.
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Simple assay for proteases based on aggregation of stimulus-responsive polypeptides.
Anal. Chem.
PUBLISHED: 05-29-2014
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Unregulated changes in protease activity are linked to many diseases including cancer. Fast, accurate, and low-cost assays for detection of these changes are being explored for early diagnosis and monitoring of these diseases and can also be used as platforms for the discovery of new drugs. We report a new methodology for the simple detection and quantification of protease activity in buffer and human serum. The assay is based on recombinant diblock polypeptides that undergo temperature- or salt-triggered micellization in water. The coronae of the micelles are linked to the water-insoluble cores by a peptide substrate that is cleaved in the presence of the target protease. Protease cleavage of the diblock polypeptide triggers the aggregation of the core-forming segment, leading to a change in solution optical density, which can be used to detect the presence of, and to quantify the concentration of, protease. We used matrix metalloproteinase-1 (MMP-1) as a model protease and found peptide aggregation time to be proportional to enzyme concentration over a range from endogenous MMP-1 level in human serum (?3 ng/mL) to 100 ng/mL (0.15-5 nM) in 40% human serum and 1-100 ng/mL in buffer. The assay does not require any intermediate steps or sophisticated data analysis, and the modular design of the assay system is amenable to straightforward adaptation for the detection of a wide range of proteases.
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Clodronate inhibits tumor angiogenesis in mouse models of ovarian cancer.
Cancer Biol. Ther.
PUBLISHED: 05-19-2014
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Bisphosphonates have been shown to inhibit and deplete macrophages. The effects of bisphosphonates on other cell types in the tumor microenvironment have been insufficiently studied. Here, we sought to determine the effects of bisphosphonates on ovarian cancer angiogenesis and growth via their effect on the microenvironment, including macrophage, endothelial and tumor cell populations.
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Metabolic shifts toward glutamine regulate tumor growth, invasion and bioenergetics in ovarian cancer.
Mol. Syst. Biol.
PUBLISHED: 05-07-2014
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Glutamine can play a critical role in cellular growth in multiple cancers. Glutamine-addicted cancer cells are dependent on glutamine for viability, and their metabolism is reprogrammed for glutamine utilization through the tricarboxylic acid (TCA) cycle. Here, we have uncovered a missing link between cancer invasiveness and glutamine dependence. Using isotope tracer and bioenergetic analysis, we found that low-invasive ovarian cancer (OVCA) cells are glutamine independent, whereas high-invasive OVCA cells are markedly glutamine dependent. Consistent with our findings, OVCA patients' microarray data suggest that glutaminolysis correlates with poor survival. Notably, the ratio of gene expression associated with glutamine anabolism versus catabolism has emerged as a novel biomarker for patient prognosis. Significantly, we found that glutamine regulates the activation of STAT3, a mediator of signaling pathways which regulates cancer hallmarks in invasive OVCA cells. Our findings suggest that a combined approach of targeting high-invasive OVCA cells by blocking glutamine's entry into the TCA cycle, along with targeting low-invasive OVCA cells by inhibiting glutamine synthesis and STAT3 may lead to potential therapeutic approaches for treating OVCAs.
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Hematogenous metastasis of ovarian cancer: rethinking mode of spread.
Cancer Cell
PUBLISHED: 05-01-2014
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Ovarian cancer has a clear predilection for metastasis to the omentum, but the underlying mechanisms involved in ovarian cancer spread are not well understood. Here, we used a parabiosis model that demonstrates preferential hematogenous metastasis of ovarian cancer to the omentum. Our studies revealed that the ErbB3-neuregulin 1 (NRG1) axis is a dominant pathway responsible for hematogenous omental metastasis. Elevated levels of ErbB3 in ovarian cancer cells and NRG1 in the omentum allowed for tumor cell localization and growth in the omentum. Depletion of ErbB3 in ovarian cancer impaired omental metastasis. Our results highlight hematogenous metastasis as an important mode of ovarian cancer metastasis. These findings have implications for designing alternative strategies aimed at preventing and treating ovarian cancer metastasis.
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Focal adhesion kinase: an alternative focus for anti-angiogenesis therapy in ovarian cancer.
Cancer Biol. Ther.
PUBLISHED: 04-23-2014
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This investigation describes the clinical significance of phosphorylated focal adhesion kinase (FAK) at the major activating tyrosine site (Y397) in epithelial ovarian cancer (EOC) cells and tumor-associated endothelial cells. FAK gene amplification as a mechanism for FAK overexpression and the effects of FAK tyrosine kinase inhibitor VS-6062 on tumor growth, metastasis, and angiogenesis were examined. FAK and phospho-FAK(Y397) were quantified in tumor (FAK-T; pFAK-T) and tumor-associated endothelial (FAK-endo; pFAK-endo) cell compartments of EOCs using immunostaining and qRT-PCR. Associations between expression levels and clinical variables were evaluated. Data from The Cancer Genome Atlas were used to correlate FAK gene copy number and expression levels in EOC specimens. The in vitro and in vivo effects of VS-6062 were assayed in preclinical models. FAK-T and pFAK-T overexpression was significantly associated with advanced stage disease and increased microvessel density (MVD). High MVD was observed in tumors with elevated endothelial cell FAK (59%) and pFAK (44%). Survival was adversely affected by FAK-T overexpression (3.03 vs 2.06 y, P = 0.004), pFAK-T (2.83 vs 1.78 y, P<0.001), and pFAK-endo (2.33 vs 2.17 y, P = 0.005). FAK gene copy number was increased in 34% of tumors and correlated with expression levels (P<0.001). VS-6062 significantly blocked EOC and endothelial cell migration as well as endothelial cell tube formation in vitro. VS-6062 reduced mean tumor weight by 56% (P = 0.005), tumor MVD by 40% (P = 0.0001), and extraovarian metastasis (P<0.01) in orthotopic EOC mouse models. FAK may be a unique therapeutic target in EOC given the dual anti-angiogenic and anti-metastatic potential of FAK inhibitors.
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Molecular biomarkers of residual disease after surgical debulking of high-grade serous ovarian cancer.
Clin. Cancer Res.
PUBLISHED: 04-22-2014
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Residual disease following primary cytoreduction is associated with adverse overall survival in patients with epithelial ovarian cancer. Accurate identification of patients at high risk of residual disease has been elusive, lacking external validity and prompting many to undergo unnecessary surgical exploration. Our goal was to identify and validate molecular markers associated with high rates of residual disease.
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Metronomic docetaxel in PRINT nanoparticles and EZH2 silencing have synergistic antitumor effect in ovarian cancer.
Mol. Cancer Ther.
PUBLISHED: 04-22-2014
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The purpose of this study was to investigate the antitumor effects of a combination of metronomic doses of a novel delivery vehicle, PLGA-PRINT nanoparticles containing docetaxel, and antiangiogenic mEZH2 siRNA incorporated into chitosan nanoparticles. In vivo dose-finding studies and therapeutic experiments were conducted in well-established orthotopic mouse models of epithelial ovarian cancer. Antitumor effects were determined on the basis of reduction in mean tumor weight and number of metastatic tumor nodules in the animals. The tumor tissues from these in vivo studies were stained to evaluate the proliferation index (Ki67), apoptosis index (cleaved caspase 3), and microvessel density (CD31). The lowest dose of metronomic regimen (0.5 mg/kg) resulted in significant reduction in tumor growth. The combination of PLGA-PRINT-docetaxel and CH-mEZH2 siRNA showed significant antitumor effects in the HeyA8 and SKOV3ip1 tumor models (P < 0.05). Individual as well as combination therapies showed significant antiangiogenic, antiproliferative, and proapoptotic effects, and combination therapy had additive effects. Metronomic delivery of PLGA-PRINT-docetaxel combined with CH-mEZH2 siRNA has significant antitumor activity in preclinical models of ovarian cancer.
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Notch3 pathway alterations in ovarian cancer.
Cancer Res.
PUBLISHED: 04-17-2014
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The Notch pathway plays an important role in the growth of high-grade serous ovarian (HGS-OvCa) and other cancers, but its clinical and biologic mechanisms are not well understood. Here, we found that the Notch pathway alterations are prevalent and significantly related to poor clinical outcome in patients with ovarian cancer. Particularly, Notch3 alterations, including amplification and upregulation, were highly associated with poor patient survival. Targeting Notch3 inhibited ovarian cancer growth and induced apoptosis. Importantly, we found that dynamin-mediated endocytosis was required for selectively activating Jagged-1-mediated Notch3 signaling. Cleaved Notch3 expression was the critical determinant of response to Notch-targeted therapy. Collectively, these data identify previously unknown mechanisms underlying Notch3 signaling and identify new, biomarker-driven approaches for therapy.
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Experiences of paradox: a qualitative analysis of living with cancer using a framework approach.
Psychooncology
PUBLISHED: 04-12-2014
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Life-threatening diseases such as cancer represent unique traumas-compared with singular, time-limited traumatic events-given their multidimensional, uncertain, and continuing nature. However, few studies have examined the impact of cancer on patients as a persistent stressor. The aim of this qualitative study is to explore patients' ongoing experiences of living with cancer and the changes encountered in this experience over time.
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miR-34a blocks osteoporosis and bone metastasis by inhibiting osteoclastogenesis and Tgif2.
Nature
PUBLISHED: 04-08-2014
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Bone-resorbing osteoclasts significantly contribute to osteoporosis and bone metastases of cancer. MicroRNAs play important roles in physiology and disease, and present tremendous therapeutic potential. Nonetheless, how microRNAs regulate skeletal biology is underexplored. Here we identify miR-34a as a novel and critical suppressor of osteoclastogenesis, bone resorption and the bone metastatic niche. miR-34a is downregulated during osteoclast differentiation. Osteoclastic miR-34a-overexpressing transgenic mice exhibit lower bone resorption and higher bone mass. Conversely, miR-34a knockout and heterozygous mice exhibit elevated bone resorption and reduced bone mass. Consequently, ovariectomy-induced osteoporosis, as well as bone metastasis of breast and skin cancers, are diminished in osteoclastic miR-34a transgenic mice, and can be effectively attenuated by miR-34a nanoparticle treatment. Mechanistically, we identify transforming growth factor-?-induced factor 2 (Tgif2) as an essential direct miR-34a target that is pro-osteoclastogenic. Tgif2 deletion reduces bone resorption and abolishes miR-34a regulation. Together, using mouse genetic, pharmacological and disease models, we reveal miR-34a as a key osteoclast suppressor and a potential therapeutic strategy to confer skeletal protection and ameliorate bone metastasis of cancers.
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Elastomeric negative acoustic contrast particles for capture, acoustophoretic transport, and confinement of cells in microfluidic systems.
Langmuir
PUBLISHED: 03-31-2014
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We present a particle-based method for the immunospecific capture and confinement of cells using acoustic radiation forces. Ultrasonic standing waves in microfluidic systems have previously been used for the continuous focusing of cells in rapid screening and sorting applications. In aqueous fluids, cells typically exhibit positive acoustic contrast and are thus forced toward the pressure nodes of a standing wave. Conversely, elastomeric particles exhibit negative acoustic contrast and travel toward the pressure antinodes. We have developed a class of elastomeric particles that are synthesized in bulk using a simple nucleation and growth process, providing precise control over their size and functional properties. We demonstrate that the biofunctionalization of these particles can allow the capture and transport of cells to the pressure antinodes solely via acoustic radiation forces, which may enable new acoustics-based cell handling techniques such as the washing, labeling, and sorting of cells with minimal preparatory steps.
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Nanopatterned antimicrobial enzymatic surfaces combining biocidal and fouling release properties.
Nanoscale
PUBLISHED: 03-25-2014
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Surfaces incorporating the antimicrobial enzyme, lysozyme, have been previously demonstrated to effectively disrupt bacterial cellular envelopes. As with any surface active antimicrobial, however, lysozyme-expressing surfaces become limited in their utility by the accumulation of dead bacteria and debris. Surfaces modified with environmentally responsive polymers, on the other hand, have been shown to reversibly attach and release both live and dead bacterial cells. In this work, we combine the antimicrobial activity of lysozyme with the fouling release capability of the thermally responsive polymer, poly(N-isopropylacrylamide) (PNIPAAm), which has a lower critical solution temperature (LCST) in water at ?32 °C. Nanopatterned PNIPAAm brushes were fabricated using interferometric lithography followed by surface-initiated polymerization. Lysozyme was then adsorbed into the polymer-free regions of the substrate between the brushes to achieve a hybrid surface with switchable antimicrobial activity and fouling-release ability in response to the change of temperature. The temperature triggered hydration and conformational change of the nanopatterned PNIPAAm brushes provide the ability to temporally regulate the spatial concealment and exposure of adsorbed lysozyme. The biocidal efficacy and release properties of the hybrid surface were tested against Escherichia coli K12 and Staphylococcus epidermidis. The hybrid surfaces facilitated the attachment of bacteria at 37 °C for E. coli and 25 °C for S. epidermidis and when the temperature is above the LCST, collapsed and dehydrated PNIPAAm chains expose lysozyme to kill attached bacteria. Changing temperature across the LCST of PNIPAAm (e.g. from 37 °C to 25 °C for E. coli or from 25 °C to 37 °C for S. epidermidis) to induce a hydration transition of PNIPAAm promoted the release of dead bacteria and debris from the surfaces upon mild shearing. These results suggest that nano-engineered surfaces can provide an effective way for actively mitigating short term bacterial biofouling.
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Diarrhea in preschool children and Lactobacillus reuteri: a randomized controlled trial.
Pediatrics
PUBLISHED: 03-17-2014
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To evaluate whether daily administration of Lactobacillus reuteri DSM 17938 reduces the frequency and duration of diarrheal episodes and other health outcomes in day school children in Mexico.
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Calcium-dependent FAK/CREB/TNNC1 signalling mediates the effect of stromal MFAP5 on ovarian cancer metastatic potential.
Nat Commun
PUBLISHED: 03-03-2014
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Ovarian cancer is the most lethal gynaecologic malignancy in the United States, and advanced serous ovarian adenocarcinoma is responsible for most ovarian cancer deaths. However, the stroma-derived molecular determinants that modulate patient survival are yet to be characterized. Here we identify a stromal gene signature for advanced high-grade serous ovarian cancer using microdissected stromal ovarian tumour samples and find that stromal microfibrillar-associated protein 5 (MFAP5) is a prognostic marker for poor survival. Further functional studies reveal that FAK/CREB/TNNC1 signalling pathways mediate the effect of MFAP5 on ovarian cancer cell motility and invasion potential. Targeting stromal MFAP5 using MFAP5-specific siRNA encapsulated in chitosan nanoparticles significantly decreases ovarian tumour growth and metastasis in vivo, suggesting that it may be a new modality of ovarian cancer treatment.
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Monocyte subpopulations in angiogenesis.
Cancer Res.
PUBLISHED: 02-20-2014
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Growing understanding of the role of the tumor microenvironment in angiogenesis has brought monocyte-derived cells into focus. Monocyte subpopulations are an increasingly attractive therapeutic target in many pathologic states, including cancer. Before monocyte-directed therapies can be fully harnessed for clinical use, understanding of monocyte-driven angiogenesis in tissue development and homeostasis, as well as malignancy, is required. Here, we provide an overview of the mechanisms by which monocytic subpopulations contribute to angiogenesis in tissue and tumor development, highlight gaps in our existing knowledge, and discuss opportunities to exploit these cells for clinical benefit.
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Nucleation and growth synthesis of siloxane gels to form functional, monodisperse, and acoustically programmable particles.
Angew. Chem. Int. Ed. Engl.
PUBLISHED: 02-17-2014
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Nucleation and growth methods offer scalable means of synthesizing colloidal particles with precisely specified size for applications in chemical research, industry, and medicine. These methods have been used to prepare a class of silicone gel particles that display a range of programmable properties and narrow size distributions. The acoustic contrast factor of these particles in water is estimated and can be tuned such that the particles undergo acoustophoresis to either the pressure nodes or antinodes of acoustic standing waves. These particles can be synthesized to display surface functional groups that can be covalently modified for a range of bioanalytical and acoustophoretic sorting applications.
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2'-OMe-phosphorodithioate-modified siRNAs show increased loading into the RISC complex and enhanced anti-tumour activity.
Nat Commun
PUBLISHED: 02-17-2014
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Improving small interfering RNA (siRNA) efficacy in target cell populations remains a challenge to its clinical implementation. Here, we report a chemical modification, consisting of phosphorodithioate (PS2) and 2'-O-Methyl (2'-OMe) MePS2 on one nucleotide that significantly enhances potency and resistance to degradation for various siRNAs. We find enhanced potency stems from an unforeseen increase in siRNA loading to the RNA-induced silencing complex, likely due to the unique interaction mediated by 2'-OMe and PS2. We demonstrate the therapeutic utility of MePS2 siRNAs in chemoresistant ovarian cancer mouse models via targeting GRAM domain containing 1B (GRAMD1B), a protein involved in chemoresistance. GRAMD1B silencing is achieved in tumours following MePS2-modified siRNA treatment, leading to a synergistic anti-tumour effect in combination with paclitaxel. Given the previously limited success in enhancing siRNA potency with chemically modified siRNAs, our findings represent an important advance in siRNA design with the potential for application in numerous cancer types.
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The impact of PKR activation: from neurodegeneration to cancer.
FASEB J.
PUBLISHED: 02-12-2014
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An inverse association between cancer and neurodegeneration is plausible because these biological processes share several genes and signaling pathways. Whereas uncontrolled cell proliferation and decreased apoptotic cell death governs cancer, excessive apoptosis contributes to neurodegeneration. Protein kinase R (PKR), an interferon-inducible double-stranded RNA protein kinase, is involved in both diseases. PKR activation blocks global protein synthesis through eIF2? phosphorylation, leading to cell death in response to a variety of cellular stresses. However, PKR also has the dual role of activating the nuclear factor ?-B pathway, promoting cell proliferation. Whereas PKR is recognized for its negative effects on neurodegenerative diseases, in part, inducing high level of apoptosis, the role of PKR activation in cancer remains controversial. In general, PKR is considered to have a tumor suppressor function, and some clinical data show a correlation between suppressed or inactivated PKR and a poor prognosis for several cancers. However, other studies show high PKR expression and activation levels in various cancers, suggesting that PKR might contribute to neoplastic progression. Understanding the cellular factors and signals involved in the regulation of PKR in these age-related diseases is relevant and may have important clinical implications. The present review highlights the current knowledge on the role of PKR in neurodegeneration and cancer, with special emphasis on its regulation and clinical implications.
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Antagonism of tumoral prolactin receptor promotes autophagy-related cell death.
Cell Rep
PUBLISHED: 01-29-2014
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Therapeutic upregulation of macroautophagy in cancer cells provides an alternative mechanism for cell death. Prolactin (PRL) and its receptor (PRLR) are considered attractive therapeutic targets because of their roles as growth factors in tumor growth and progression. We utilized G129R, an antagonist peptide of PRL, to block activity of the tumoral PRL/PRLR axis, which resulted in inhibition of tumor growth in orthotopic models of human ovarian cancer. Prolonged treatment with G129R induced the accumulation of redundant autolysosomes in 3D cancer spheroids, leading to a type II programmed cell death. This inducible autophagy was a noncanonical beclin-1-independent pathway and was sustained by an astrocytic phosphoprotein (PEA-15) and protein kinase C zeta interactome. Lower levels of tumoral PRL/PRLR in clinical samples were associated with longer patient survival. Our findings provide an understanding of the mechanisms of tumor growth inhibition through targeting PRL/PRLR and may have clinical implications.
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Epicardial adipose tissue thickness and its association with adiponectin in metabolic syndrome patients from Mérida, Venezuela.
Arq Bras Endocrinol Metabol
PUBLISHED: 01-24-2014
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To study the relationship between epicardial adipose tissue (EAT) thickness and plasma levels of adiponectin in Venezuelan patients.
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Hypoxia-mediated downregulation of miRNA biogenesis promotes tumour progression.
Nat Commun
PUBLISHED: 01-20-2014
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Cancer-related deregulation of miRNA biogenesis has been suggested, but the underlying mechanisms remain elusive. Here we report a previously unrecognized effect of hypoxia in the downregulation of Drosha and Dicer in cancer cells that leads to dysregulation of miRNA biogenesis and increased tumour progression. We show that hypoxia-mediated downregulation of Drosha is dependent on ETS1/ELK1 transcription factors. Moreover, mature miRNA array and deep sequencing studies reveal altered miRNA maturation in cells under hypoxic conditions. At a functional level, this phenomenon results in increased cancer progression in vitro and in vivo, and data from patient samples are suggestive of miRNA biogenesis downregulation in hypoxic tumours. Rescue of Drosha by siRNAs targeting ETS1/ELK1 in vivo results in significant tumour regression. These findings provide a new link in the mechanistic understanding of global miRNA downregulation in the tumour microenvironment.
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Delivery of negatively charged liposomes into the atherosclerotic plaque of apolipoprotein E-deficient mouse aortic tissue.
J Liposome Res
PUBLISHED: 01-20-2014
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Liposomes have been used to diagnose and treat cancer and, to a lesser extent, cardiovascular disease. We previously showed the uptake of anionic liposomes into the atheromas of Watanabe heritable hyperlipidemic rabbits within lipid pools. However, the cellular distribution of anionic liposomes in atherosclerotic plaque remains undescribed. In addition, how anionic liposomes are absorbed into atherosclerotic plaque is unclear. We investigated the uptake and distribution of anionic liposomes in atherosclerotic plaque in aortic tissues from apolipoprotein E-deficient (ApoE(-/-)) mice. To facilitate the tracking of liposomes, we used liposomes containing fluorescently labeled non-silencing small interfering RNA. Confocal microscopy analysis showed the uptake of anionic liposomes into atherosclerotic plaque and colocalization with macrophages. Transmission electron microscopy analysis revealed anionic liposomal accumulation in macrophages. To investigate how anionic liposomes cross the local endothelial barrier, we examined the role of clathrin-mediated endocytosis in human coronary artery endothelial cells (HCAECs) treated with or without the inflammatory cytokine tumor necrosis factor (TNF)-?. Pretreatment with amantadine, an inhibitor of clathrin-mediated endocytosis, significantly decreased liposomal uptake in HCAECs treated with or without TNF-? by 77% and 46%, respectively. Immunoblot analysis showed that endogenous clathrin expression was significantly increased in HCAECs stimulated with TNF-? but was inhibited by amantadine. These studies indicated that clathrin-mediated endocytosis is partly responsible for the uptake of liposomes by endothelial cells. Our results suggest that anionic liposomes target macrophage-rich areas of vulnerable plaque in ApoE(-)(/)(-) mice; this finding may lead to the development of novel diagnostic and therapeutic strategies for treating vulnerable plaque in humans.
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Antimicrobial oligo(p-phenylene-ethynylene) film deposited by resonant infrared matrix-assisted pulsed laser evaporation.
Colloids Surf B Biointerfaces
PUBLISHED: 01-18-2014
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The antimicrobial oligomer, oligo(p-phenylene-ethynylene) (OPE), was deposited as thin films by resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) on solid substrates and exhibited light-induced biocidal activity. The biocidal activity of OPE thin films deposited by spin-coating and drop-casting was also investigated for comparison. Enhanced bacterial attachment and biocidal efficiency of the film deposited by RIR-MAPLE were observed and attributed to nanoscale surface topography of the thin film.
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Soft robotic concepts in catheter design: an on-demand fouling-release urinary catheter.
Adv Healthc Mater
PUBLISHED: 01-15-2014
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Infectious biofilms are problematic in many healthcare-related devices and are especially challenging and ubiquitous in urinary catheters. This report presents an on-demand fouling-release methodology to mechanically disrupt and remove biofilms, and proposes this method for the active removal of infectious biofilms from the previously inaccessible main drainage lumen of urinary catheters. Mature Proteus mirabilis crystalline biofilms detach from silicone elastomer substrates upon application of strain to the substrate, and increasing the strain rate increases biofilm detachment. The study presents a quantitative relationship between applied strain rate and biofilm debonding through an analysis of biofilm segment length and the driving force for debonding. Based on this mechanism, hydraulic and pneumatic elastomer actuation is used to achieve surface strain selectively within the lumen of prototypes of sections of a fouling-release urinary catheter. Proof-of-concept prototypes of sections of active, fouling-release catheters are constructed using techniques typical to soft robotics including 3D printing and replica molding, and those prototypes demonstrate release of mature P. mirabilis crystalline biofilms (e.g., ?90%) from strained surfaces. These results provide a basis for the development of a new urinary catheter technology in which infectious biofilms are effectively managed through new methods that are entirely complementary to existing approaches.
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Autocrine effects of tumor-derived complement.
Cell Rep
PUBLISHED: 01-11-2014
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We describe a role for the complement system in enhancing cancer growth. Cancer cells secrete complement proteins that stimulate tumor growth upon activation. Complement promotes tumor growth via a direct autocrine effect that is partially independent of tumor-infiltrating cytotoxic T cells. Activated C5aR and C3aR signal through the PI3K/AKT pathway in cancer cells, and silencing the PI3K or AKT gene in cancer cells eliminates the progrowth effects of C5aR and C3aR stimulation. In patients with ovarian or lung cancer, higher tumoral C3 or C5aR mRNA levels were associated with decreased overall survival. These data identify a role for tumor-derived complement proteins in promoting tumor growth, and they therefore have substantial clinical and therapeutic implications.
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EDD enhances cell survival and cisplatin resistance and is a therapeutic target for epithelial ovarian cancer.
Carcinogenesis
PUBLISHED: 12-30-2013
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The E3 ubiquitin ligase EDD is overexpressed in recurrent, platinum-resistant ovarian cancers, suggesting a role in tumor survival and/or platinum resistance. EDD knockdown by siRNA induced apoptosis in A2780ip2, OVCAR5, and ES-2 ovarian cancer cells, correlating with loss of the pro-survival protein Mcl-1 through a GSK-3?-independent mechanism. SiRNA to EDD or Mcl-1 induced comparable levels of apoptosis in A2780ip2 and ES-2 cells. Stable overexpression of Mcl-1 protected cells from apoptosis following EDD knockdown, accompanied by a loss of endogenous, but not exogenous, Mcl-1 protein, suggesting that EDD regulated Mcl-1 synthesis. Indeed, EDD knockdown induced a 1.87-fold decrease in Mcl-1 mRNA and EDD transfection enhanced murine Mcl-1 promoter driven luciferase expression 5-fold. To separate EDD survival and potential cisplatin resistance functions, we generated EDD shRNA stable cell lines that could survive initial EDD knockdown and showed that these cells were four- to 24-fold more sensitive to cisplatin. Moreover, transient EDD overexpression in COS-7 cells was sufficient to promote cisplatin resistance 2.4-fold, dependent upon its E3 ligase activity. In vivo, mouse intraperitoneal ES-2 and A2780ip2 xenograft experiments showed that mice treated with EDD siRNA by nanoliposomal delivery (DOPC) and cisplatin had significantly less tumor burden than those treated with control siRNA/DOPC alone (ES-2, 77.9% reduction, p=0.004; A2780ip2, 75.9% reduction, p=0.042) or control siRNA/DOPC with cisplatin in ES-2 (64.4% reduction, p=0.035), with a trend in A2780ip2 (60.3% reduction, p=0.168). These results identify EDD as a dual regulator of cell survival and cisplatin resistance and suggest EDD is a therapeutic target for ovarian cancer.
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Cloning, expression, purification and characterization of his-tagged human glucose-6-phosphate dehydrogenase: a simplified method for protein yield.
Protein J.
PUBLISHED: 10-23-2013
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Glucose-6-phosphate dehydrogenase (G6PD) catalyzes the first step of the pentose phosphate pathway. In erythrocytes, the functionality of the pathway is crucial to protect these cells against oxidative damage. G6PD deficiency is the most frequent enzymopathy in humans with a global prevalence of 4.9 %. The clinical picture is characterized by chronic or acute hemolysis in response to oxidative stress, which is related to the low cellular activity of G6PD in red blood cells. The disease is heterogeneous at genetic level with around 160 mutations described, mostly point mutations causing single amino acid substitutions. The biochemical studies aimed to describe the detrimental effects of mutations on the functional and structural properties of human G6PD are indispensable to understand the molecular physiopathology of this disease. Therefore, reliable systems for efficient expression and purification of the protein are highly desirable. In this work, human G6PD was heterologously expressed in Escherichia coli and purified by immobilized metal affinity chromatography in a single chromatographic step. The structural and functional characterization indicates that His-tagged G6PD resembles previous preparations of recombinant G6PD. In contrast with previous protein yield systems, our method is based on commonly available resources and fully accessible laboratory equipment; therefore, it can be readily implemented.
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Nanotechnology in cancer therapy.
J Drug Target
PUBLISHED: 09-30-2013
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Cancer is one of the major causes of mortality worldwide and advanced techniques for therapy are urgently needed. The development of novel nanomaterials and nanocarriers has allowed a major drive to improve drug delivery in cancer. The major aim of most nanocarrier applications has been to protect the drug from rapid degradation after systemic delivery and allowing it to reach tumor site at therapeutic concentrations, meanwhile avoiding drug delivery to normal sites as much as possible to reduce adverse effects. These nanocarriers are formulated to deliver drugs either by passive targeting, taking advantage of leaky tumor vasculature or by active targeting using ligands that increase tumoral uptake potentially resulting in enhanced antitumor efficacy, thus achieving a net improvement in therapeutic index. The rational design of nanoparticles plays a critical role since structural and physical characteristics, such as size, charge, shape, and surface characteristics determine the biodistribution, pharmacokinetics, internalization and safety of the drugs. In this review, we focus on several novel and improved strategies in nanocarrier design for cancer therapy.
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Nanopatterned smart polymer surfaces for controlled attachment, killing, and release of bacteria.
ACS Appl Mater Interfaces
PUBLISHED: 09-16-2013
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Model surfaces with switchable functionality based on nanopatterned, thermoresponsive poly(N-isopropylacrylamide) (PNIPAAm) brushes were fabricated using interferometric lithography combined with surface-initiated polymerization. The temperature-triggered hydration and conformational changes of nanopatterned PNIPAAm brushes reversibly modulate the spatial concealment and exposure of molecules that are immobilized in the intervals between nanopatterned brushes. A biocidal quaternary ammonium salt (QAS) was used to demonstrate the utility of nanopatterned PNIPAAm brushes to control biointerfacial interactions with bacteria. QAS was integrated into polymer-free regions of the substrate between nanopatterned PNIPAAm brushes. The biocidal efficacy and release properties of these surfaces were tested against Escherichia coli K12. Above the lower critical solution temperature (LCST) of PNIPAAm, desolvated, collapsed polymer chains facilitate the attachment of bacteria and expose QAS moieties that kill attached bacteria. Upon a reduction of the temperature below the LCST, swollen PNIPAAm chains promote the release of dead bacteria. These results demonstrate that nanopatterned PNIPAAm/QAS hybrid surfaces are model systems that exhibit an ability to undergo noncovalent, dynamic, and reversible changes in structure that can be used to control the attachment, killing, and release of bacteria in response to changes in temperature.
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Membrane-mediated neuroprotection by curcumin from amyloid-?-peptide-induced toxicity.
Langmuir
PUBLISHED: 09-04-2013
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Amyloid-? peptide (A?)-membrane interactions have been implicated in the formation of toxic oligomers that permeabilize membranes, allowing an influx of calcium ions and triggering cell death in the pathogenesis of Alzheimers disease (AD). Curcumin, a small dietary polyphenolic molecule, has been shown to reduce A?-induced toxicity and AD pathology. We investigate here the effect of curcumin on A?40-induced toxicity in cultured human neuroblastoma SH-SY5Y cells and test a novel neuroprotection mechanism in which curcumin reduces A?-membrane interactions and attenuates A?-induced membrane disruptions. Predominantly monomeric A?40 exerts toxicity toward SH-SY5Y cells and has been shown to insert spontaneously into anionic lipid monolayers at the air/water interface, resulting in the misfolding and assembly of A? into ?-sheet-enriched oligomers. Concomitantly, membrane morphology and lipid packing are disrupted. Curcumin dose-dependently ameliorates A?-induced neurotoxicity and reduces either the rate or extent of A? insertion into anionic lipid monolayers. Moreover, curcumin reduces A?-induced dye leakage from lipid-bilayer-covered, dye-loaded, porous silica microspheres. Because curcumin neither affects the inherent surface activity of A? nor modifies the membrane properties, it reduces A? insertion by directly attenuating A?-membrane interactions and reducing A?-induced membrane disruption. Although the exact molecular mechanism of curcumins membrane protective effect remains unclear, this effect could in part contribute to curcumins neuroprotective effect with respect to A?-induced toxicity. Our work reveals a novel molecular mechanism by which curcumin reduces A?-related pathology and toxicity and suggests a therapeutic strategy for preventing or treating AD by targeting the inhibition of A?-induced membrane disruption.
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Therapeutic synergy between microRNA and siRNA in ovarian cancer treatment.
Cancer Discov
PUBLISHED: 09-03-2013
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Development of improved RNA interference-based strategies is of utmost clinical importance. Although siRNA-mediated silencing of EphA2, an ovarian cancer oncogene, results in reduction of tumor growth, we present evidence that additional inhibition of EphA2 by a microRNA (miRNA) further "boosts" its antitumor effects. We identified miR-520d-3p as a tumor suppressor upstream of EphA2, whose expression correlated with favorable outcomes in two independent patient cohorts comprising 647 patients. Restoration of miR-520d-3p prominently decreased EphA2 protein levels, and suppressed tumor growth and migration/invasion both in vitro and in vivo. Dual inhibition of EphA2 in vivo using 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC) nanoliposomes loaded with miR-520d-3p and EphA2 siRNA showed synergistic antitumor efficiency and greater therapeutic efficacy than either monotherapy alone. This synergy is at least in part due to miR-520d-3p targeting EphB2, another Eph receptor. Our data emphasize the feasibility of combined miRNA-siRNA therapy, and will have broad implications for innovative gene silencing therapies for cancer and other diseases.
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Common causes of glucose oxidase instability in in vivo biosensing: a brief review.
J Diabetes Sci Technol
PUBLISHED: 08-06-2013
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Clinical management of diabetes must overcome the challenge of in vivo glucose sensors exhibiting lifetimes of only a few days. Limited sensor life originates from compromised enzyme stability of the sensing enzyme. Sensing enzymes degrade in the presence of low molecular weight materials (LMWM) and hydrogen peroxide in vivo. Sensing enzymes could be made to withstand these degradative effects by (1) stabilizing the microenvironment surrounding the sensing enzyme or (2) improving the structural stability of the sensing enzyme genetically. We review the degradative effect of LMWM and hydrogen peroxide on the sensing enzyme glucose oxidase (GOx). In addition, we examine advances in stabilizing GOx against degradation using hybrid silica gels and genetic engineering of GOx. We conclude molecularly engineered GOx combined with silica-based encapsulation provides an avenue for designing long-term in vivo sensor systems.
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The E104D mutation increases the susceptibility of human triosephosphate isomerase to proteolysis. Asymmetric cleavage of the two monomers of the homodimeric enzyme.
Biochim. Biophys. Acta
PUBLISHED: 07-26-2013
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The deficiency of human triosephosphate isomerase (HsTIM) generates neurological alterations, cardiomyopathy and premature death. The mutation E104D is the most frequent cause of the disease. Although the wild type and mutant exhibit similar kinetic parameters, it has been shown that the E104D substitution induces perturbation of an interfacial water network that, in turn, reduces the association constant between subunits promoting enzyme inactivation. To gain further insight into the effects of the mutation on the structure, stability and function of the enzyme, we measured the sensitivity of recombinant E104D mutant and wild type HsTIM to limited proteolysis. The mutation increases the susceptibility to proteolysis as consequence of the loss of rigidity of its overall 3-D structure. Unexpectedly, it was observed that proteolysis of wild type HsTIM generated two different stable nicked dimers. One was formed in relatively short times of incubation with proteinase K; as shown by spectrometric and crystallographic data, it corresponded to a dimer containing a nicked monomer and an intact monomer. The formation of the other nicked species requires relatively long incubation times with proteinase K and corresponds to a dimer with two clipped subunits. The first species retains 50% of the original activity, whereas the second species is inactive. Collectively, we found that the E104D mutant is highly susceptible to proteolysis, which in all likelihood contributes to the pathogenesis of enzymopathy. In addition, the proteolysis data on wild type HsTIM illustrate an asymmetric conduct of the two monomers.
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Liposomal siRNA nanocarriers for cancer therapy.
Adv. Drug Deliv. Rev.
PUBLISHED: 06-24-2013
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Small interfering RNAs (siRNA) have recently emerged as a new class of therapeutics with a great potential to revolutionize the treatment of cancer and other diseases. A specifically designed siRNA binds and induces post-transcriptional silencing of target genes (mRNA). Clinical applications of siRNA-based therapeutics have been limited by their rapid degradation, poor cellular uptake, and rapid renal clearance following systemic administration. A variety of synthetic and natural nanoparticles composed of lipids, polymers, and metals have been developed for siRNA delivery, with different efficacy and safety profiles. Liposomal nanoparticles have proven effective in delivering siRNA into tumor tissues by improving stability and bioavailability. While providing high transfection efficiency and a capacity to form complexes with negatively charged siRNA, cationic lipids/liposomes are highly toxic. Negatively charged liposomes, on the other hand, are rapidly cleared from circulation. To overcome these problems we developed highly safe and effective neutral lipid-based nanoliposomes that provide robust gene silencing in tumors following systemic (intravenous) administration. This delivery system demonstrated remarkable antitumor efficacy in various orthotopic human cancer models in animals. Here, we briefly overview this and other lipid- based approaches with preclinical applications in different tumor models for cancer therapy and potential applications as siRNA-nanotherapeutics in human cancers.
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Molecular circuit involving KLK4 integrates androgen and mTOR signaling in prostate cancer.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 06-24-2013
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The androgen receptor (AR) and the phosphoinositide 3-kinase (PI3K)/protein kinase B/mammalian target of rapamycin (mTOR) signaling are two of the major proliferative pathways in a number of tissues and are the main therapeutic targets in various disorders, including prostate cancer (PCa). Previous work has shown that there is reciprocal feedback regulation of PI3K and AR signaling in PCa, suggesting that cotargeting both pathways may enhance therapeutic efficacy. Here we show that proteins encoded by two androgen-regulated genes, kallikrein related peptidase 4 (KLK4) and promyelocytic leukemia zinc finger (PLZF), integrate optimal functioning of AR and mTOR signaling in PCa cells. KLK4 interacts with PLZF and decreases its stability. PLZF in turn interacts with AR and inhibits its function as a transcription factor. PLZF also activates expression of regulated in development and DNA damage responses 1, an inhibitor of mTORC1. Thus, a unique molecular switch is generated that regulates both AR and PI3K signaling. Consistently, KLK4 knockdown results in a significant decline in PCa cell proliferation in vitro and in vivo, decreases anchorage-independent growth, induces apoptosis, and dramatically sensitizes PCa cells to apoptosis-inducing agents. Furthermore, in vivo nanoliposomal KLK4 siRNA delivery in mice bearing PCa tumors results in profound remission. These results demonstrate that the activities of AR and mTOR pathways are maintained by KLK4, which may thus be a viable target for therapy.
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Elastomeric microparticles for acoustic mediated bioseparations.
J Nanobiotechnology
PUBLISHED: 06-14-2013
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Acoustophoresis has been utilized successfully in applications including cell trapping, focusing, and purification. One current limitation of acoustophoresis for cell sorting is the reliance on the inherent physical properties of cells (e.g., compressibility, density) instead of selecting cells based upon biologically relevant surface-presenting antigens. Introducing an acoustophoretic cell sorting approach that allows biochemical specificity may overcome this limitation, thus advancing the value of acoustophoresis approaches for both the basic research and clinical fields.
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Stable and fluid multilayer phospholipid-silica thin films: mimicking active multi-lamellar biological assemblies.
ACS Nano
PUBLISHED: 05-31-2013
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Phospholipid-based nanomaterials are of interest in several applications including drug delivery, sensing, energy harvesting, and as model systems in basic research. However, a general challenge in creating functional hybrid biomaterials from phospholipid assemblies is their fragility, instability in air, insolubility in water, and the difficulty of integrating them into useful composites that retain or enhance the properties of interest, therefore limiting there use in integrated devices. We document the synthesis and characterization of highly ordered and stable phospholipid-silica thin films that resemble multilamellar architectures present in nature such as the myelin sheath. We have used a near room temperature chemical vapor deposition method to synthesize these robust functional materials. Highly ordered lipid films are exposed to vapors of silica precursor resulting in the formation of nanostructured hybrid assemblies. This process is simple, scalable, and offers advantages such as exclusion of ethanol and no (or minimal) need for exposure to mineral acids, which are generally required in conventional sol-gel synthesis strategies. The structure of the phospholipid-silica assemblies can be tuned to either lamellar or hexagonal organization depending on the synthesis conditions. The phospholipid-silica films exhibit long-term structural stability in air as well as when placed in aqueous solutions and maintain their fluidity under aqueous or humid conditions. This platform provides a model for robust implementation of phospholipid multilayers and a means toward future applications of functional phospholipid supramolecular assemblies in device integration.
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Therapeutic Silencing of Bcl-2 by Systemically Administered siRNA Nanotherapeutics Inhibits Tumor Growth by Autophagy and Apoptosis and Enhances the Efficacy of Chemotherapy in Orthotopic Xenograft Models of ER (-) and ER (+) Breast Cancer.
Mol Ther Nucleic Acids
PUBLISHED: 05-29-2013
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Bcl-2 is overexpressed in about a half of human cancers and 50-70% of breast cancer patients, thereby conferring resistance to conventional therapies and making it an excellent therapeutic target. Small interfering RNA (siRNA) offers novel and powerful tools for specific gene silencing and molecularly targeted therapy. Here, we show that therapeutic silencing of Bcl-2 by systemically administered nanoliposomal (NL)-Bcl-2 siRNA (0.15?mg siRNA/kg, intravenous) twice a week leads to significant antitumor activity and suppression of growth in both estrogen receptor-negative (ER(-)) MDA-MB-231 and ER-positive (+) MCF7 breast tumors in orthotopic xenograft models (P < 0.05). A single intravenous injection of NL-Bcl-2-siRNA provided robust and persistent silencing of the target gene expression in xenograft tumors. NL-Bcl-2-siRNA treatment significantly increased the efficacy of chemotherapy when combined with doxorubicin in both MDA-MB-231 and MCF-7 animal models (P < 0.05). NL-Bcl-2-siRNA treatment-induced apoptosis and autophagic cell death, and inhibited cyclin D1, HIF1? and Src/Fak signaling in tumors. In conclusion, our data provide the first evidence that in vivo therapeutic targeting Bcl-2 by systemically administered nanoliposomal-siRNA significantly inhibits growth of both ER(-) and ER(+) breast tumors and enhances the efficacy of chemotherapy, suggesting that therapeutic silencing of Bcl-2 by siRNA is a viable approach in breast cancers.Molecular Therapy-Nucleic Acids (2013) 2, e121; doi:10.1038/mtna.2013.45; published online 10 September 2013.
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[Achievement of cardiovascular prevention goals, pharmacologic prescription and major cardiovascular events among patients with coronary disease].
Rev Med Chil
PUBLISHED: 04-19-2013
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Background: Implementation of health programs to reduce cardiovascular risk, are needed for secondary prevention of cardiovascular diseases. Aim: To evalúate achievements of secondary prevention goals, pharmacologic prescription and major cardiovascular events in patients with coronary artery disease. Material and Methods: Patients who had a first event of acute coronary syndrome, angioplasty or revascularization surgery, between January 2008 and June 2010, were contacted for a clinical and laboratory evaluation between June and October 2011. Results: Seven hundred and two medical records were reviewed and 245 eligible patients were identified. Ofthese, we assessed 202 patients aged 64 ± 10 years (70% males). Sixty seven percent had two ormore cardiovascular riskfactors. A goal ofHDL cholesterol level over 40 mg/dL was achieved in 91 % of patients, smoking cessation in 84% and a total cholesterol < 200 mg/dL in 66%. A blood pressure below 130/85 mm Hgwas achieved in 30% of patients, a normal BMI in 19% and LDL cholesterol levels below 70 mg/dL in 18%. At the moment of assessment, 87%> were using aspirin, 78%> statins, 74% angiotensin converting enzyme inhibitors or angiotensin II receptor antagonists and 66%o were using ? - blockers. Twenty two percent of patients had a major cardiovascular event during the follow up, which lasted 28 ± 8 months. Conclusions: A low percentage of cardiovascular goals achievement was observed in this sample of patients, with a high prevalence of overweight and obesity. A high percentage quit smoking after their first cardiovascular event. Despite the high percentage of drug prescription, hypertension and dyslipidemia were not fully controlled.
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Effect of detergents on the thermal behavior of elastin-like polypeptides.
Biopolymers
PUBLISHED: 03-27-2013
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Elastin-like polypeptide (ELP) fusions have been designed to allow large-scale, nonchromatographic purification of many soluble proteins by using the inverse transition cycling (ITC) method; however, the sensitivity of the aqueous lower critical solubility phase transition temperature (T(t) ) of ELPs to the addition of cosolutes, including detergents, may be a potential hindrance in purification of proteins with surface hydrophobicity in such a manner. To identify detergents that are known to solubilize such proteins (e.g., membrane proteins) and that have little effect on the T(t) of the ELP, we screened a number of detergents with respect to their effects on the T(t) and secondary structures of a model ELP (denoted here as ELP180). We found that mild detergents (e.g., n-dodecyl-?-D-maltoside, Triton-X100, and 3-[(3-cholamidopropyl) dimethylamino]-1-propanesulfonate) do not alter the phase transition behavior or structure (as probed by circular dichroism) of ELP180. This result is in contrast to previous studies that showed a strong effect of other detergents (e.g., sodium dodecylsulfate) on the T(t) of ELPs. Our results clearly indicate that mild detergents do not preclude ITC-based separation of ELPs, and thus that ELP fusions may prove to be useful in the purification of detergent-solubilized recombinant hydrophobic proteins, including membrane proteins, which are otherwise notoriously difficult to extract and purify by conventional separation methods (e.g., chromatography). © 2012 Wiley Periodicals, Inc.
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Nanopatterned polymer brushes as switchable bioactive interfaces.
Nanoscale
PUBLISHED: 03-26-2013
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We report convenient methods for synthesis of nanopatterned, thermally responsive brushes of poly(N-isopropyl acrylamide) over large areas (e.g., 1 cm(2)) to form model, dynamic, biofunctional surfaces. The new nanopatterned brush structure can be used to control (i) the rate of both nonspecific and biospecific adsorption processes at the polymer-graft-free regions of the substrate, and (ii) the rate of cell detachment. These capabilities have potential implications in a number of areas of biotechnology including biosensing, separations and cell culture.
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[Giant Bakers cyst treated with intralessional methotrexate].
Cir Cir
PUBLISHED: 03-07-2013
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Synovial cyst is composed by a fibrous wall; lining by a thin layer of synovial cells containing synovial fluid, the prototype of these, in the knee is the Bakers cyst, which is located abnormally in the gastrocnemius semimembranous bursa. Bakers cyst prevalence ranges from 5 - 38%. Clinical diagnosis is supported by the presence of increased volume of soft tissues located in the popliteal region.
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Tumour angiogenesis regulation by the miR-200 family.
Nat Commun
PUBLISHED: 03-02-2013
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The miR-200 family is well known to inhibit the epithelial-mesenchymal transition, suggesting it may therapeutically inhibit metastatic biology. However, conflicting reports regarding the role of miR-200 in suppressing or promoting metastasis in different cancer types have left unanswered questions. Here we demonstrate a difference in clinical outcome based on miR-200s role in blocking tumour angiogenesis. We demonstrate that miR-200 inhibits angiogenesis through direct and indirect mechanisms by targeting interleukin-8 and CXCL1 secreted by the tumour endothelial and cancer cells. Using several experimental models, we demonstrate the therapeutic potential of miR-200 delivery in ovarian, lung, renal and basal-like breast cancers by inhibiting angiogenesis. Delivery of miR-200 members into the tumour endothelium resulted in marked reductions in metastasis and angiogenesis, and induced vascular normalization. The role of miR-200 in blocking cancer angiogenesis in a cancer-dependent context defines its utility as a potential therapeutic agent.
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A core human primary tumor angiogenesis signature identifies the endothelial orphan receptor ELTD1 as a key regulator of angiogenesis.
Cancer Cell
PUBLISHED: 02-27-2013
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Limited clinical benefits derived from anti-VEGF therapy have driven the identification of new targets involved in tumor angiogenesis. Here, we report an integrative meta-analysis to define the transcriptional program underlying angiogenesis in human cancer. This approach identified ELTD1, an orphan G-protein-coupled receptor whose expression is induced by VEGF/bFGF and repressed by DLL4 signaling. Extensive analysis of multiple cancer types demonstrates significant upregulation of ELTD1 in tumor-associated endothelial cells, with a higher expression correlating with favorable prognosis. Importantly, ELTD1 silencing impairs endothelial sprouting and vessel formation in vitro and in vivo, drastically reducing tumor growth and greatly improving survival. Collectively, these results provide insight into the regulation of tumor angiogenesis and highlight ELTD1 as key player in blood vessel formation.
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Integrated analyses identify a master microRNA regulatory network for the mesenchymal subtype in serous ovarian cancer.
Cancer Cell
PUBLISHED: 02-16-2013
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Integrated genomic analyses revealed a miRNA-regulatory network that further defined a robust integrated mesenchymal subtype associated with poor overall survival in 459 cases of serous ovarian cancer (OvCa) from The Cancer Genome Atlas and 560 cases from independent cohorts. Eight key miRNAs, including miR-506, miR-141, and miR-200a, were predicted to regulate 89% of the targets in this network. Follow-up functional experiments illustrate that miR-506 augmented E-cadherin expression, inhibited cell migration and invasion, and prevented TGF?-induced epithelial-mesenchymal transition by targeting SNAI2, a transcriptional repressor of E-cadherin. In human OvCa, miR-506 expression was correlated with decreased SNAI2 and VIM, elevated E-cadherin, and beneficial prognosis. Nanoparticle delivery of miR-506 in orthotopic OvCa mouse models led to E-cadherin induction and reduced tumor growth.
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ATP11B mediates platinum resistance in ovarian cancer.
J. Clin. Invest.
PUBLISHED: 02-14-2013
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Platinum compounds display clinical activity against a wide variety of solid tumors; however, resistance to these agents is a major limitation in cancer therapy. Reduced platinum uptake and increased platinum export are examples of resistance mechanisms that limit the extent of DNA damage. Here, we report the discovery and characterization of the role of ATP11B, a P-type ATPase membrane protein, in cisplatin resistance. We found that ATP11B expression was correlated with higher tumor grade in human ovarian cancer samples and with cisplatin resistance in human ovarian cancer cell lines. ATP11B gene silencing restored the sensitivity of ovarian cancer cell lines to cisplatin in vitro. Combined therapy of cisplatin and ATP11B-targeted siRNA significantly decreased cancer growth in mice bearing ovarian tumors derived from cisplatin-sensitive and -resistant cells. In vitro mechanistic studies on cellular platinum content and cisplatin efflux kinetics indicated that ATP11B enhances the export of cisplatin from cells. The colocalization of ATP11B with fluorescent cisplatin and with vesicular trafficking proteins, such as syntaxin-6 (STX6) and vesicular-associated membrane protein 4 (VAMP4), strongly suggests that ATP11B contributes to secretory vesicular transport of cisplatin from Golgi to plasma membrane. In conclusion, inhibition of ATP11B expression could serve as a therapeutic strategy to overcome cisplatin resistance.
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Tunable assembly of colloidal crystal alloys using magnetic nanoparticle fluids.
ACS Nano
PUBLISHED: 02-12-2013
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We demonstrate a magnetic technique for assembling bidisperse and tridisperse colloidal particle fluids into a variety of complex structures with dimensionality ranging from 0-D (rings) to 1-D (chains) to 2-D (tiles). Compared with prior work on bidisperse particles that are commensurate in size, here we explore the assembly of different sized particles, and we show that due to packing constraints, new particle structures can be realized experimentally. Extending these experiments to a tridisperse system, we demonstrate that at low concentrations the smallest particle does not change the underlying crystal structures of the bidisperse system; however, it can assist in the formation of crystallite structures that were not stable in a bidisperse system. Additionally, we discovered that the smallest particle mimics the role of the ferrofluid, by shifting the locations in phase space where the bidisperse crystal structures can be experimentally obtained. Finally, we demonstrate that 3-particle crystal structures can be tuned by varying the strength of the external field, which is not possible in a 2-particle system.
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Enhancing chemotherapy response with sustained EphA2 silencing using multistage vector delivery.
Clin. Cancer Res.
PUBLISHED: 02-05-2013
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RNA interference has the potential to specifically knockdown the expression of target genes and thereby transform cancer therapy. However, lack of effective delivery of siRNA has dramatically limited its in vivo applications. We have developed a multistage vector (MSV) system, composed of discoidal porous silicon particles loaded with nanotherapeutics, that directs effective delivery and sustained release of siRNA in tumor tissues. In this study, we evaluated therapeutic efficacy of MSV-loaded EphA2 siRNA (MSV/EphA2) with murine orthotopic models of metastatic ovarian cancers as a first step toward development of a new class of nanotherapeutics for the treatment of ovarian cancer.
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Elastomeric negative acoustic contrast particles for affinity capture assays.
Anal. Chem.
PUBLISHED: 02-05-2013
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This report describes the development of elastomeric capture microparticles (EC?Ps) and their use with acoustophoretic separation to perform microparticle assays via flow cytometry.We have developed simple methods to form EC?Ps by cross-linking droplets of common commercially available silicone precursors in suspension followed by surface functionalization with biomolecular recognition reagents. The EC?Ps are compressible particles that exhibit negative acoustic contrast in ultrasound when suspended in aqueous media, blood serum, or diluted blood. In this study, these particles have been functionalized with antibodies to bind prostate specific antigen and immunoglobulin (IgG). Specific separation of the EC?Ps from blood cells is achieved by flowing them through a microfluidic acoustophoretic device that uses an ultrasonic standing wave to align the blood cells, which exhibit positive acoustic contrast, at a node in the acoustic pressure distribution while aligning the negative acoustic contrast EC?Ps at the antinodes. Laminar flow of the separated particles to downstream collection ports allows for collection of the separated negative contrast (EC?Ps) and positive contrast particles (cells). Separated EC?Ps were analyzed via flow cytometry to demonstrate nanomolar detection for prostate specific antigen in aqueous buffer and picomolar detection for IgG in plasma and diluted blood samples. This approach has potential applications in the development of rapid assays that detect the presence of low concentrations of biomarkers in a number of biological sample types.
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Src activation by ?-adrenoreceptors is a key switch for tumour metastasis.
Nat Commun
PUBLISHED: 01-31-2013
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Noradrenaline can modulate multiple cellular functions important for cancer progression; however, how this single extracellular signal regulates such a broad array of cellular processes is unknown. Here we identify Src as a key regulator of phosphoproteomic signalling networks activated in response to beta-adrenergic signalling in cancer cells. These results also identify a new mechanism of Src phosphorylation that mediates beta-adrenergic/PKA regulation of downstream networks, thereby enhancing tumour cell migration, invasion and growth. In human ovarian cancer samples, high tumoural noradrenaline levels were correlated with high pSrc(Y419) levels. Moreover, among cancer patients, the use of beta blockers was significantly associated with reduced cancer-related mortality. Collectively, these data provide a pivotal molecular target for disrupting neural signalling in the tumour microenvironment.
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Tat-activating regulatory DNA-binding protein regulates glycolysis in hepatocellular carcinoma by regulating the platelet isoform of phosphofructokinase through microRNA 520.
Hepatology
PUBLISHED: 01-30-2013
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Metabolic changes are common features of many cancer cells and are frequently associated with the clinical outcome of patients with various cancers, including hepatocellular carcinoma (HCC). Thus, aberrant metabolic pathways in cancer cells are attractive targets for cancer therapy. However, our understanding of cancer-specific regulatory mechanisms of cell metabolism is still very limited. We found that Tat-activating regulatory DNA-binding protein (TARDBP) is a novel regulator of glycolysis in HCC cells. TARDBP regulates expression of the platelet isoform of phosphofructokinase (PFKP), the rate-limiting enzyme of glycolysis that catalyzes the irreversible conversion of fructose-6-phosphate to fructose-1,6-bisphosphate. Silencing of TARDBP expression in multiple HCC cell lines leads to impaired glucose metabolism and inhibition of in vitro and in vivo growth of HCC cells. Notably, the microRNA 520 (miR-520) family is an intermediate regulator of TARDBP-mediated regulation of glycolysis. Mechanistically, TARDBP suppressed expression of the miR-520 family, which, in turn, inhibited expression of PFKP. We further showed that expression of TARDBP is significantly associated with the overall survival of patients with HCC. Conclusion: Our study provides new mechanistic insights into the regulation of glycolysis in HCC cells and reveals TARDBP as a potential therapeutic target for HCC.
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Identification of FGFR4 as a potential therapeutic target for advanced-stage, high-grade serous ovarian cancer.
Clin. Cancer Res.
PUBLISHED: 01-23-2013
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To evaluate the prognostic value of fibroblast growth factor receptor 4 (FGFR4) protein expression in patients with advanced-stage, high-grade serous ovarian cancer, delineate the functional role of FGFR4 in ovarian cancer progression, and evaluate the feasibility of targeting FGFR4 in serous ovarian cancer treatment.
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Bioinspired surfaces with dynamic topography for active control of biofouling.
Adv. Mater. Weinheim
PUBLISHED: 01-06-2013
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Dynamic change of the surface area and topology of elastomers is used as a general, environmentally friendly approach for effectively detaching micro- and macro-fouling organisms adhered on the elastomer surfaces. Deformation of elastomer surfaces under electrical or pneumatic actuation can debond various biofilms and barnacles. The bio-inspired dynamic surfaces can be fabricated over large areas through simple and practical processes. This new mechanism is complementary with existing materials and methods for biofouling control.
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Cystathionine Beta-Synthase (CBS) Contributes to Advanced Ovarian Cancer Progression and Drug Resistance.
PLoS ONE
PUBLISHED: 01-01-2013
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Epithelial ovarian cancer is the leading cause of gynecologic cancer deaths. Most patients respond initially to platinum-based chemotherapy after surgical debulking, however relapse is very common and ultimately platinum resistance emerges. Understanding the mechanism of tumor growth, metastasis and drug resistant relapse will profoundly impact the therapeutic management of ovarian cancer.
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Structural and functional perturbation of giardia lamblia triosephosphate isomerase by modification of a non-catalytic, non-conserved region.
PLoS ONE
PUBLISHED: 01-01-2013
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We have previously proposed triosephosphate isomerase of Giardia lamblia (GlTIM) as a target for rational drug design against giardiasis, one of the most common parasitic infections in humans. Since the enzyme exists in the parasite and the host, selective inhibition is a major challenge because essential regions that could be considered molecular targets are highly conserved. Previous biochemical evidence showed that chemical modification of the non-conserved non-catalytic cysteine 222 (C222) inactivates specifically GlTIM. The inactivation correlates with the physicochemical properties of the modifying agent: addition of a non-polar, small chemical group at C222 reduces the enzyme activity by one half, whereas negatively charged, large chemical groups cause full inactivation.
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Up-regulation of Cav?3 subunit in primary sensory neurons increases voltage-activated Ca2+ channel activity and nociceptive input in neuropathic pain.
J. Biol. Chem.
PUBLISHED: 12-20-2011
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High voltage-activated calcium channels (HVACCs) are essential for synaptic and nociceptive transmission. Although blocking HVACCs can effectively reduce pain, this treatment strategy is associated with intolerable adverse effects. Neuronal HVACCs are typically composed of ?(1), ? (Cav?), and ?(2)? subunits. The Cav? subunit plays a crucial role in the membrane expression and gating properties of the pore-forming ?(1) subunit. However, little is known about how nerve injury affects the expression and function of Cav? subunits in primary sensory neurons. In this study, we found that Cav?(3) and Cav?(4) are the most prominent subtypes expressed in the rat dorsal root ganglion (DRG) and dorsal spinal cord. Spinal nerve ligation (SNL) in rats significantly increased mRNA and protein levels of the Cav?(3), but not Cav?(4), subunit in the DRG. SNL also significantly increased HVACC currents in small DRG neurons and monosynaptic excitatory postsynaptic currents of spinal dorsal horn neurons evoked from the dorsal root. Intrathecal injection of Cav?(3)-specific siRNA significantly reduced HVACC currents in small DRG neurons and the amplitude of monosynaptic excitatory postsynaptic currents of dorsal horn neurons in SNL rats. Furthermore, intrathecal treatment with Cav?(3)-specific siRNA normalized mechanical hyperalgesia and tactile allodynia caused by SNL but had no significant effect on the normal nociceptive threshold. Our findings provide novel evidence that increased expression of the Cav?(3) subunit augments HVACC activity in primary sensory neurons and nociceptive input to dorsal horn neurons in neuropathic pain. Targeting the Cav?(3) subunit at the spinal level represents an effective strategy for treating neuropathic pain.
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Development of the use of conversational cues to assess reality status.
J Cogn Dev
PUBLISHED: 10-22-2011
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In this study we assessed childrens ability to use information overheard in other peoples conversations to judge the reality status of a novel entity. Three- to 9-year-old children (N = 101) watched video clips in which two adults conversed casually about a novel being. Videos contained statements that either explicitly denied, explicitly affirmed, or implicitly acknowledged the entitys existence. Results indicated that children of all ages used statements of denial to discount the reality status of the novel entity, but that this ability improved with age. By age 5, children used implicit existence cues to judge a novel entity as being real. Not until age 9, however, did children begin to doubt the existence of entities whose reality status was explicitly affirmed in conversation. Overall, results indicate that the ability to use conversational cues to determine reality status is present in some children as early as age 3, but recognition of the nuanced language of belief continues to develop during the elementary-school years.
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A case of an abdominal mass: follicular lymphoma.
Perm J
PUBLISHED: 08-23-2011
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Follicular lymphoma (FL) is the second most common subtype of non-Hodgkin lymphoma. The disease usually affects older individuals, with the average age at diagnosis being 63.5 years. Only in 4% of cases is the disease diagnosed in individuals younger than age 40 years. The case presented in this report describes the diagnosis of FL in a 38-year-old woman and highlights the variability of this disease. Tumor grading, disease staging, and the Follicular Lymphoma International Prognostic Index score can be valuable aids in prognosis. Treatment consists of close observation or radiation therapy for early-stage disease, and rituximab with combination chemotherapy regimens for more advanced disease. Cure is rare. Treatment is predominately handled by oncologists, but these patients will likely first present to their primary care physicians. Symptoms can be subtle at times, so it is essential to be able to recognize them to provide the patient with timely treatment.
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Effect of polymer chain length on membrane perturbation activity of cationic phenylene ethynylene oligomers and polymers.
Langmuir
PUBLISHED: 08-02-2011
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The interactions of poly(phenylene ethynylene)- (PPE-) based cationic conjugated polyelectrolytes (CPEs) and oligo(phenylene ethynylene)s (OPEs) with different model lipid membrane systems were investigated to gain insight into the relationship between molecular structure and membrane perturbation ability. The CPE and OPE compounds exhibit broad-spectrum antimicrobial activity, and cell walls and membranes are believed to be their main targets. To better understand how the size, in terms of the number of repeat units, of the CPEs and OPEs affects their membrane disruption activities, a series of PPE-based CPEs and OPEs were synthesized and studied. A number of photophysical techniques were used to investigate the interactions of CPEs and OPEs with model membranes, including unilamellar vesicles and lipid monolayers at the air/water interface. CPE- or OPE-induced dye leakage from vesicles reveals that the CPEs and OPEs selectively perturb model bacterial membranes and that their membrane perturbation abilities are highly dependent on molecular size. Consistent with dye-leakage assay results, the CPEs and OPEs also exhibit chain-length-dependent ability to insert into 1,2-dipalmitoyl-sn-glycero-3-phospho-(1-rac-glycerol) (DPPG) monolayers. Our results suggest that, for PPE-based CPE and OPE antimicrobials, chain length can be tuned to optimize their membrane perturbation ability.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

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.