Triphenyl Tin Benzimidazolethiol, a Novel Antitumor Agent, Induces Mitochondrial-Mediated Apoptosis in Human Cervical Cancer Cells via Suppression of HPV-18 Encoded E6

Here we report the effect of TPT-benzimidazolethiol, a novel anti-tumor agent developed by our group, on the apoptotic pathway of human cervical carcinoma cells. Treatment of HeLa cells with TPT-benzimidazolethiol arrests the cell cycle at G0/G1 phase and transcriptionally downregulates HPV-encoded E6, restoring p53 expression from E6 suppression. Increased p53 accumulation up-regulates p21/waf and ultimately induces apoptosis. The effect of TPT-benzimidazolethiol is far more potent in inducing apoptosis than cisplatin. Treatment with TPT-benzimidazolethiol in HeLa cells is accompanied by the up-regulation of Bak at the transcriptional level, resulting in the release of cytochrome c and Smac/DIABLO from mitochondria to cytosol and, subsequently, the activation of procaspase-9, -3 and PARP, suggesting that TPT-benzimidazolethiol induced-apoptosis signaling is by an intrinsic mitochondrial pathway. Taken together, we propose that TPT-benzimidazolethiol could has the potential to be developed into a new therapeutic agent for treating HPV-associated cervical neoplasia.