Thioridazine inhibits angiogenesis and tumor growth by targeting the VEGFR-2/PI3K/mTOR pathway in ovarian cancer xenografts

Abstract

Thioridazine, a member of the phenothiazine family, is a powerful anti-anxiety and anti-psychotic drug. It can also suppress the growth of several types of tumor in vitro. In the current study, we evaluated the direct anti-tumor and anti-angiogenic effects of thioridazine in vivo. The injection of thioridazine into human ovarian tumor xenografts in nude mice significantly inhibited tumor growth by similar to fivefold, and also decreased tumor vascularity. In addition, thioridazine inhibited the phosphorylation of the signaling molecules downstream of phosphatidylinositol-3'-kinase (PI3K), including Akt, phosphoinositide-dependent protein kinase 1 (PDK1), and mammalian target of rapamycin (mTOR), during ovarian tumor progression via vascular endothelial growth factor receptor 2 (VEGFR-2). These results provide convincing evidence that thioridazine regulates endothelial cell function and subsequent angiogenesis by inhibiting VEGFR-2/PI3K/mTOR signal transduction. Collectively, these results strongly suggest that thioridazine might be a novel anti-tumor and anti-angiogenic agent for use in ovarian cancer.