Anti-tumor effect of radiation response by combined treatment with angiogenesis inhibitor, TNP-470, in oral squamous cell carcinoma.

Blocking angiogenesis may enhance conventional anticancer treatments such as radiation therapy. In this study, we examined the effects of the angiogenesis inhibitor TNP-470 on human OSCC cell lines HSC2 and KB, with combining radiation therapy in the nude mouse. We evaluated cell-induced neovascularization with dorsal air sac assay, and selected two cells (HSC2: low, KB: high) with different level of cell-induced angiogenesis. The angiogenesis inhibitor TNP-470 was given 30 mg/kg s.c. daily on day 1-5, and irradiation, 8 Gy x 1, was administered on day 1 each week for 3 weeks. Significant inhibition of tumor growth relative to untreated controls was achieved in KB cells showing high induced angiogenesis with both TNP-470 (P < 0.01) and radiation (P < 0.01) and combining TNP-470 and radiation (P < 0.01). We saw little effect of TNP-470 either alone or in addition to the effect of radiation on the HSC2 cells showing low induced angiogenesis. These results suggested that TNP-470 significantly enhanced the effect of radiation on the cells with high neovascularization. These findings indicated that individual evaluation of each tumor neovascularization potential will be important before deciding the anti-angiogenesis treatment.