JoVE Visualize What is visualize?
Stop Reading. Start Watching.
Advanced Search
Stop Reading. Start Watching.
Regular Search
Find video protocols related to scientific articles indexed in Pubmed.
Ratiometric Activatable Cell-Penetrating Peptides Label Pancreatic Cancer, Enabling Fluorescence-Guided Surgery, Which Reduces Metastases and Recurrence in Orthotopic Mouse Models.
Ann. Surg. Oncol.
PUBLISHED: 08-11-2014
Show Abstract
Hide Abstract
The aim of this study was to evaluate the efficacy of using matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9)-cleavable ratiometric activatable cell-penetrating peptides (RACPPs) conjugated to Cy5 and Cy7 fluorophores to accurately label pancreatic cancer for fluorescence-guided surgery (FGS) in an orthotopic mouse model.
Related JoVE Video
Matrix-metalloproteinases in head and neck carcinoma-cancer genome atlas analysis and fluorescence imaging in mice.
Otolaryngol Head Neck Surg
PUBLISHED: 08-04-2014
Show Abstract
Hide Abstract
(1) Obtain matrix-metalloproteinase (MMP) expression profiles for head and neck squamous cell carcinoma (HNSCC) specimens from the Cancer Genomic Atlas (TCGA). (2) Demonstrate HNSCC imaging using MMP-cleavable, fluorescently labeled ratiometric activatable cell-penetrating peptide (RACPP).
Related JoVE Video
Dual targeting of integrin ?v?3 and matrix metalloproteinase-2 for optical imaging of tumors and chemotherapeutic delivery.
Mol. Cancer Ther.
PUBLISHED: 04-15-2014
Show Abstract
Hide Abstract
Activatable cell-penetrating peptides (ACPP) provide a general strategy for molecular targeting by exploiting the extracellular protease activities associated with disease. Previous work used a matrix metalloproteinase (MMP-2 and 9)-cleavable sequence in the ACPP to target contrast agents for tumor imaging and fluorescence-guided surgery. To improve specificity and sensitivity for MMP-2, an integrin ?(v)?(3)-binding domain, cyclic-RGD, was covalently linked to the ACPP. This co-targeting strategy relies on the interaction of MMP-2 with integrin ?(v)?(3), which are known to associate via the hemopexin domain of MMP-2. In U87MG glioblastoma cells in culture, dual targeting greatly improved ACPP uptake compared with either MMP or integrin ?(v)?(3) targeting alone. In vivo, dual-targeted ACPP treatment resulted in tumor contrast of 7.8 ± 1.6, a 10-fold higher tumor fluorescence compared with the negative control peptide, and increased probe penetration into the core of MDA-MB-231 tumors. This platform also significantly improved efficacy of the chemotherapeutic monomethylauristatin E (MMAE) in both MDA-MB-231 orthotopic human and syngeneic Py230 murine breast tumors. Treatment with cyclic-RGD-PLGC(Me)AG-MMAE-ACPP resulted in complete tumor regression in one quarter of MDA-MB-231 tumor-bearing mice, compared with no survival in the control groups. This rational mechanism for amplified delivery of imaging and potent chemotherapeutic agents avoids the use of antibodies and may be of considerable generality.
Related JoVE Video
Detection and monitoring of localized matrix metalloproteinase upregulation in a murine model of asthma.
Am. J. Physiol. Lung Cell Mol. Physiol.
PUBLISHED: 02-07-2014
Show Abstract
Hide Abstract
Extracellular proteases including matrix metalloproteinases (MMPs) are speculated to play a significant role in chronic lung diseases, such as asthma. Although increased protease expression has been correlated with lung pathogenesis, the relationship between localized enzyme activity and disease progression remains poorly understood. We report the application of MMP-2/9 activatable cell-penetrating peptides (ACPPs) and their ratiometric analogs (RACPPs) for in vivo measurement of protease activity and distribution in the lungs of mice that were challenged with the allergen ovalbumin. MMP-2/9 activity was increased greater than twofold in whole, dissected lungs from acutely challenged mice compared with control mice (P=1.8×10(-4)). This upregulation of MMP-2/9 activity was localized around inflamed airways with 1.6-fold higher protease-dependent ACPP uptake surrounding diseased airways compared with adjacent, pathologically normal lung parenchyma (P=0.03). MMP-2/9 activity detected by ACPP cleavage colocalized with gelatinase activity measured with in situ dye-quenched gelatin. For comparison, neutrophil elastase activity and thrombin activity, detected with elastase- and thrombin-cleavable RACPPs, respectively, were not significantly elevated in acutely allergen-challenged mouse lungs. The results demonstrate that ACPPs, like the MMP-2/9-activated and related ACPPs, allow for real-time detection of protease activity in a murine asthma model, which should improve our understanding of protease activation in asthma disease progression and help elucidate new therapy targets or act as a mechanism for therapeutic drug delivery.
Related JoVE Video
Redox, Ionic Strength, and pH Sensitive Supramolecular Polymer Assemblies.
J Polym Sci A Polym Chem
PUBLISHED: 10-14-2009
Show Abstract
Hide Abstract
Supramolecular complex of a cationic surfactant and oppositely charged disulfide containing polyelectrolyte was found to form micelle type aggregates at concentration much lower than the critical aggregate concentration (CAC) of the surfactant itself. We show that this difference can be utilized to generate stimulus-sensitive disassembly of these structures. This can be achieved either by converting the polyelectrolyte counterions to monovalent counterions in response to a stimulus or by simply weakening the interaction between the polymer and the surfactant in the presence of a stimulus. We have utilized three different stimuli to demonstrate these possibilities.
Related JoVE Video
Generating peptide titration-type curves using polymeric reverse micelles as selective extraction agents along with matrix-assisted laser desorption ionization-mass spectrometry detection.
Anal. Chem.
PUBLISHED: 05-23-2009
Show Abstract
Hide Abstract
Amphiphilic homopolymers that self-assemble into reverse micelles in nonpolar solvents have been used by us in the context of a two-phase liquid-liquid extraction protocol to selectively extract peptides from aqueous solution for MALDI-MS detection. In this manuscript, we investigate the scope of these materials in terms of its extraction capabilities, using compounds with varying isoelectric points (pI) and pK(a) values over a range of aqueous solution pHs. We find that the aqueous solution pH and analyte pK(a) values are the major factors controlling extraction selectivity. We also find that the experimental extraction efficiencies correspond very well with the fractional compositions of species calculated using analyte pK(a) values, indicating that these extraction materials can be used to simultaneously generate titration-type curves for each individual peptide in a mixture. We predict that such titration curves, along with accurate mass measurements, could represent a new way of improving protein identification procedures.
Related JoVE Video
Fluorescence patterns from supramolecular polymer assembly and disassembly for sensing metallo- and nonmetalloproteins.
J. Am. Chem. Soc.
PUBLISHED: 05-14-2009
Show Abstract
Hide Abstract
Critical aggregation concentration (CAC) of surfactants is lowered when polyelectrolytes act as counterions. At a concentration in between the CACs of the surfactant and the polymer-surfactant complex, protein-induced disassemblies can be achieved. This is because, when proteins competitively bind to the polyelectrolytes, the surfactants are not capable of sustaining a micelle-type assembly at this concentration. Since these amphiphilic aggregates are capable of noncovalently sequestering hydrophobic guest molecules, the protein binding induced disassembly process also results in a guest release from these assemblies. We show here that the change in fluorescence with different proteins is dependent not only on the nature of the polymer-surfactant complex, but also on the fluorescent transducer. Two processes can be responsible for the observed fluorescence change: fluorophore guest release from the hydrophobic interior of the assembly and excited state quenching due to complementary components in the analyte. The latter mechanism is especially possible with metalloproteins. We show here that an excited state quenching is possible at nanomolar concentrations of the proteins, while the disassembly based fluorescence reduction is the dominant pathway at micromolar concentrations.
Related JoVE Video
Real-time in vivo molecular detection of primary tumors and metastases with ratiometric activatable cell-penetrating peptides.
Cancer Res.
Show Abstract
Hide Abstract
Management of metastatic disease is integral to cancer treatment. Evaluation of metastases often requires surgical removal of all anatomically susceptible lymph nodes for ex vivo pathologic examination. We report a family of novel ratiometric activatable cell-penetrating peptides, which contain Cy5 as far red fluorescent donor and Cy7 as near-infrared fluorescent acceptor. Cy5 is quenched in favor of Cy7 re-emission until the intervening linker is cut by tumor-associated matrix metalloproteinases-2 and 9 (MMP2,9) or elastases. Such cleavage increases the Cy5:Cy7 emission ratio 40-fold and triggers tissue retention of the Cy5-containing fragment. This ratiometric increase provides an accelerated and quantifiable metric to identify primary tumors and metastases to liver and lymph nodes with increased sensitivity and specificity. This technique represents a significant advance over existing nonratiometric protease sensors and sentinel lymph node detection methods, which give no information about cancer invasion.
Related JoVE Video
Ratiometric activatable cell-penetrating peptides provide rapid in vivo readout of thrombin activation.
Angew. Chem. Int. Ed. Engl.
Show Abstract
Hide Abstract
In real time: thrombin activation in vivo can be imaged in real time with ratiometric activatable cell penetrating peptides (RACPPs). RACPPs are designed to combine 1) dual-emission ratioing, 2) far red to infrared wavelengths for in vivo mammalian imaging, and 3) cleavage-dependent spatial localization. The most advanced RACPP uses norleucine (Nle)-TPRSFL as a linker that increases sensitivity to thrombin by about 90-fold.
Related JoVE Video
In Vivo Targeting of Hydrogen Peroxide by Activatable Cell-Penetrating Peptides.
J. Am. Chem. Soc.
Show Abstract
Hide Abstract
A hydrogen peroxide (H2O2)-activated cell-penetrating peptide was developed through incorporation of a boronic acid-containing cleavable linker between polycationic cell-penetrating peptide and polyanionic fragments. Fluorescence labeling of the two ends of the molecule enabled monitoring its reaction with H2O2 through release of the highly adhesive cell-penetrating peptide and disruption of fluorescence resonance energy transfer. The H2O2 sensor selectively reacts with endogenous H2O2, in cell culture to monitor the oxidative burst of promyelocytes, and in vivo to image lung inflammation. Targeting H2O2 has potential applications in imaging and therapy of diseases related to oxidative stress.
Related JoVE Video

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.