abt-510 and Ovarian-Neoplasms

Epithelial ovarian cancer (EOC) comprises approximately 90% of ovarian cancers and arises from the surface epithelium. Typical treatment of EOC involves cytoreductive surgery combined with chemotherapy. More recent therapies have targeted the tumor vasculature using antiangiogenic compounds such as thrombospondin-1 (TSP-1). TSP-1 mimetic peptides such as ABT-510 have been created and have been in various clinical trials. We have previously shown that ABT-510 reduces abnormal vasculature associated with tumor tissue and increases the presence of mature blood vessels. It has been hypothesized that treatment with antiangiogenic compounds would allow increased delivery of cytotoxic agents and enhance treatment. In this study, we evaluated the potential role of ABT-510 and various chemotherapeutics (cisplatin and paclitaxel) on tumor progression, angiogenesis, and the benefits of combinational treatments on tissue uptake and perfusion using an orthotopic syngeneic mouse model of EOC. Animals were treated with ABT-510 (100 mg/kg per day) alone or in combination with cisplatin (2 mg/kg per 3 days) or paclitaxel (10 mg/kg per 2 days) at 60 days after tumor induction. Radiolabeled and fluorescently labeled paclitaxel demonstrated a significant increase in tumor uptake after ABT-510 treatment. Combined treatment with ABT-510 and cisplatin or paclitaxel resulted in a significant increase in tumor cell and tumor endothelial cell apoptosis and a resultant decrease in ovarian tumor size. Combined treatment also regressed secondary lesions and eliminated the presence of abdominal ascites. The results from this study show that through vessel normalization, ABT-510 increases uptake of chemotherapy drugs and can induce regression of advanced ovarian cancer.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Biomimetics; Cell Line; Cisplatin; Endothelium, Vascular; Enzyme-Linked Immunosorbent Assay; Female; Immunoblotting; Mice; Mice, Inbred C57BL; Morbidity; Neoplasms, Glandular and Epithelial; Oligopeptides; Ovarian Neoplasms; Paclitaxel; Receptors, Vascular Endothelial Growth Factor; Survival Rate; Thrombospondin 1; Treatment Outcome; Vascular Endothelial Growth Factor A; Xenograft Model Antitumor Assays

Epithelial ovarian cancer (EOC) is the fifth most common cancer in women and is characterized by a low 5-year survival rate. One strategy that can potentially improve the overall survival rate in ovarian cancer is the use of antitumor agents such as ABT-510. ABT-510 is a small mimetic peptide of the naturally occurring antiangiogenic compound thrombospondin-1 and has been shown to significantly reduce tumor growth and burden in preclinical mouse models and in naturally occurring tumors in dogs. This is the first evaluation of ABT-510 in a preclinical model of human EOC. Tumorigenic mouse surface epithelial cells were injected into the bursa of C57BL/6 mice that were treated with either 100 mg/kg ABT-510 or an equivalent amount of PBS. ABT-510 caused a significant reduction in tumor size, ascites fluid volume, and secondary lesion dissemination when compared with PBS controls. Analysis of the vasculature of ABT-510-treated mice revealed vascular remodeling with smaller diameter vessels and lower overall area, increased number of mature vessels, and decreased tissue hypoxia. Tumors of ABT-510-treated mice had a significantly higher proportion of apoptotic tumor cells compared with the PBS-treated controls. Immunoblot analysis of cell lysates revealed a reduction in vascular endothelial growth factor, vascular endothelial growth factor receptor-2, and proliferating cell nuclear antigen protein expression as well as expression of members of the phosphatidylinositol 3-kinase and mitogen-activated protein kinase survival pathways. In vitro, ABT-510 induced tumor cell apoptosis in mouse and human ovarian cancer cells. This study shows ABT-510 as a promising candidate for inhibiting tumor growth and ascites formation in human EOC.

Topics: Animals; Antineoplastic Agents; Apoptosis; Biomarkers; CD36 Antigens; Disease Models, Animal; Disease Progression; Epithelial Cells; Fas Ligand Protein; Female; Mice; Mice, Inbred C57BL; Mice, Knockout; Neovascularization, Pathologic; Oligopeptides; Ovarian Neoplasms; Thrombospondin 1