COMP-Ang1 Potentiates the Antitumor Activity of 5-Fluorouracil by Improving Tissue Perfusion in Murine Lewis Lung Carcinoma

Chemotherapy is often hindered by abnormal tumor vascularity, which causes impaired delivery of drugs into the tumor. Angiopoietin-1 has potent roles in angiogenesis and vessel maturation. We report here that an angiopoietin-1 variant, COMP-Ang1, promotes vascular remodeling and pericyte coverage and thereby promotes the efficient delivery of a chemotherapeutic drug into tumors of murine Lewis lung carcinoma. The combination of COMP-Ang1 with the cytotoxic drug 5-fluorouracil potentiated the effect of 5-fluorouracil on tumor growth without increasing animal toxicity. Moreover, COMP-Ang1 increased perfusion into the tumor. Although COMP-Ang1 increased the functional vasculature in the tumor, COMP-Ang1 alone did not promote tumor growth, possibly due to its promotion of increased pericyte coverage. This study suggests that COMP-Ang1 may improve the microcirculation within a tumor by increasing functional vasculature and tissue perfusion and that the combination of chemotherapy together with COMP-Ang1 might be an advantageous therapeutic approach.