Citation Details

Journal Article

in vivo imaging; atherosclerosis; cathepsin K; fluorescence; imaging; inflammation; AngioSense

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Journal Article

AngioSense 680; anti-angiogenic; anti-tumorigenic; Cancer; FMT1 (VisEn); FMT-Solaris; In vivo imaging (VisEn); intraperitoneal injection; mice

Antiangiogenesis has become a promising pillar in modern cancer therapy. This study investigates the antiangiogenic effects of the PEGylated Adnectin[TM], CT-322, in a murine Colo-205 xenograft tumor model. CT-322 specifically binds to and blocks vascular endothelial growth factor receptor (VEGFR-2). Adnectins are a novel class of targeted biologics engineered from the 10th domain of human fibronectin. CT-322 treated tumors exhibited a significant reduction in tumor growth of 69%, a 2.8 times lower tumor surface area and fewer necrotic areas. Control tumors showed a 2.36-fold higher microvessel density (MVD) and a 2.42 times higher vessel volume in corrosion casts. The vascular architecture in CT-322-treated tumors was characterized by a strong normalization of vasculature. This was quantified in corrosion casts of CT-322 treated tumors in which the intervascular distance (a reciprocal parameter indicative of vessel density) and the distance between two consecutive branchings were assessed, with these distances being 2.21 times and 2.37 times greater than in controls, respectively. Fluorescence molecular tomography (FMT) equally affirmed the inhibitory effects of CT-322 on tumor vasculature as indicated by a 60% reduction of the vascular probe, AngioSense, accumulating in tumor tissue, as a measurement of vascular permeability. Moreover, AngioSense accumulation was reduced as early as 24 h after starting treatment. The sum of these effects on tumor vasculature illustrates the anti-angiogenic mechanism underlying the antitumor activity of CT-322 and provides support for further evaluation of this Adnectin in combinatorial strategies with standard of care therapies.

Journal Article

AngioSense, Annexin Vivo, Annexin-Vivo, Aniline Compounds/*pharmacology; Animals; Antineoplastic Agents/*pharmacology; *Apoptosis; Breast Neoplasms/drug therapy/*physiopathology; Cell Line, Tumor; Female; Green Fluorescent Proteins; Humans; Image Processing, Computer-Assisted; Mice; Mice, Nude; Mitochondrial Membranes/drug effects/*physiology; Mitochondrial Proteins/metabolism; Molecular Imaging/*methods; Pancreatic Neoplasms/drug therapy/*physiopathology; Proto-Oncogene Proteins c-bcl-2/antagonists & inhibitors; Recombinant Fusion Proteins/metabolism; Single-Cell Analysis; Sulfonamides/*pharmacology; Tumor Microenvironment

Observing drug responses in the tumor microenvironment in vivo can be technically challenging. As a result, cellular responses to molecularly targeted cancer drugs are often studied in cell culture, which does not accurately represent the behavior of cancer cells growing in vivo. Using high-resolution microscopy and fluorescently labeled genetic reporters for apoptosis, we developed an approach to visualize drug-induced cell death at single-cell resolution in vivo. Stable expression of the mitochondrial intermembrane protein IMS-RP was established in human breast and pancreatic cancer cells. Image analysis was then used to quantify release of IMS-RP into the cytoplasm upon apoptosis and irreversible mitochondrial permeabilization. Both breast and pancreatic cancer cells showed higher basal apoptotic rates in vivo than in culture. To study drug-induced apoptosis, we exposed tumor cells to navitoclax (ABT-263), an inhibitor of Bcl-2, Bcl-xL, and Bcl-w, both in vitro and in vivo. Although the tumors responded to Bcl-2 inhibition in vivo, inducing apoptosis in around 20% of cancer cells, the observed response was much higher in cell culture. Together, our findings show an imaging technique that can be used to directly visualize cell death within the tumor microenvironment in response to drug treatment.

Journal Article

AngioSense, IVIS, Alphavirus Infections/pathology/*therapy/virology; Animals; Antineoplastic Agents, Phytogenic/therapeutic use; Blotting, Western; Cell Membrane Permeability; Combined Modality Therapy; Cricetinae; Drug Delivery Systems; Female; *Genetic Vectors; Humans; Mice; Mice, SCID; Neovascularization, Pathologic/*prevention & control; Neuroblastoma/blood supply/therapy/virology; *Oncolytic Virotherapy; Ovarian Neoplasms/*blood supply/*therapy/virology; Paclitaxel/therapeutic use; Sindbis Virus/*physiology; Vascular Endothelial Growth Factor A/metabolism; Xenograft Model Antitumor Assays

Genetic instability of cancer cells generates resistance after initial responses to chemotherapeutic agents. Several oncolytic viruses have been designed to exploit specific signatures of cancer cells, such as important surface markers or pivotal signaling pathways for selective replication. It is less likely for cancer cells to develop resistance given that mutations in these cancer signatures would negatively impact tumor growth and survival. However, as oncolytic viral vectors are large particles, they suffer from inefficient extravasation from tumor blood vessels. Their ability to reach cancer cells is an important consideration in achieving specific oncolytic targeting and potential vector replication. Our previous studies indicated that the Sindbis viral vectors target tumor cells by the laminin receptor. Here, we present evidence that modulating tumor vascular leakiness, using VEGF and/or metronomic chemotherapy regimens, significantly enhances tumor vascular permeability and directly enhances oncolytic Sindbis vector targeting in tumor models. Because host-derived vascular endothelium cells are genetically stable and less likely to develop resistance to chemotherapeutics, a combined metronomic chemotherapeutics and oncolytic vector regimen should provide a new approach for cancer therapy. This mechanism could explain the synergistic treatment outcomes observed in clinical trials of combined therapies.

Journal Article

Beta-cells; GLP1-R; imaging; targeting; in vivo imaging; VivoTag; AngioSense; Diabetes

The ability to image and ultimately quantitate beta-cell mass in vivo will likely have far reaching implications in the study of diabetes biology, in the monitoring of disease progression or response to treatment, as well as for drug development. Here, using animal models, we report on the synthesis, characterization of, and intravital microscopic imaging properties of a near infrared fluorescent exendin-4 analogue with specificity for the GLP-1 receptor on beta cells (E4K12-Fl). The agent demonstrated sub-nanomolar EC50 binding concentrations, with high specificity and binding could be inhibited by GLP-1R agonists. Following intravenous administration to mice, pancreatic islets were readily distinguishable from exocrine pancreas, achieving target-to-background ratios within the pancreas of 6:1, as measured by intravital microscopy. Serial imaging revealed rapid accumulation kinetics (with initial signal within the islets detectable within 3 minutes and peak fluorescence within 20 minutes of injection) making this an ideal agent for in vivo imaging.