Sam68 reduces cisplatin-induced apoptosis in tongue carcinoma

Shuwei Chen, Huan Li, Shimin Zhuang, Ji Zhang, Fan Gao, Xidi Wang, WenKuan Chen, Ming Song

Resistance to anticancer agents is a major obstacle for successful chemotherapy in tongue squamous cancer. Sam68 is an oncogenic-related protein in oral tongue squamous cell carcinoma functions as a signaling molecule mediating apoptosis, whose over-expression is associated with the clinicopathologic characteristics and prognosis of patients. The present study was to examine the effect of Sam68 on chemotherapeutics-induced apoptosis in oral tongue squamous cell carcinoma, and its clinical significance in oral tongue squamous cell carcinoma progression. The effect of Sam68 on apoptosis induced by cisplatin was examined both in vitro and in vivo, using Annexin V staining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assays. Real-time PCR and Western blotting analysis were used to detect mRNA and protein expression levels. Upregulation of Sam68 significantly inhibited cisplatin-induced apoptosis in oral tongue squamous cell carcinoma cells, associated with induction of anti-apoptotic proteins caspase-9, caspase-3, and PARP. In contrast, Silencing Sam68 expression significantly enhanced the sensitivity of oral tongue squamous cell carcinoma cells to apoptosis induced by cisplatin both in vitro and in vivo. The current study suggests that Sam68 could enhance the anti-apoptosis activity of oral tongue squamous cell carcinoma cells. Sam68 is a potential pharmacologic target for the treatment of oral tongue squamous cell carcinoma and inhibition of Sam68 expression might represent a novel strategy to sensitize oral tongue squamous cell carcinoma to chemotherapy.