Metronomic doxifluridine chemotherapy combined with the anti-angiogenic agent TNP-470 inhibits the growth of human uterine carcinosarcoma xenografts

Uterine carcinosarcoma is a highly aggressive gynecological neoplasm that responds poorly to conventional chemotherapy and radiotherapy. Metronomic chemotherapy is accepted as a new approach for Cancer treatment, and its underlying mechanism seems to involve the suppression of angiogenesis. However, the efficacy of metronomic and anti-angiogenic therapies against uterine carcinosarcoma is unknown. The anti-angiogenic effect of doxifluridine was assessed in vitro using human umbilical vein endothelial cells (HUVEC) co-cultured with FU-MMT-1 human uterine carcinosarcoma cells. The antitumor and anti-angiogenic effects of metronomic doxifluridine (delivered via oral gavage) in combination with TNP-470 were evaluated in vivo. Tumor vascularity was assessed by contrast-enhanced color Doppler ultrasound, laser Doppler and microvessel density staining. Doxifluridine suppressed tube formation of HUVEC and vascular endothelial growth factor production by FU-MMT-1 cells. Metronomic doxifluridine alone significantly suppressed tumor growth compared with the untreated (control) group, while metronomic doxifluridine in combination with TNP-470 significantly inhibited tumor growth compared with each treatment alone. A significant reduction of intratumoral vascularity was observed in FU-MMT-1 xenografts following treatment with metronomic doxifluridine in combination with TNP-470, as compared with each treatment alone. Intestinal bleeding was only observed when the maximum tolerated dose of doxifluridine was administered in combination with TNP-470. Metronomic doxifluridine chemotherapy in combination with TNP-470 might be effective for uterine carcinosarcoma without marked toxicity, possibly acting via its potent anti-angiogenic effects. Clinical studies are needed to evaluate the safety and efficacy of this treatment in humans.