The cytotoxic effect of GW843682X on nasopharyngeal carcinoma.

GW843682X is a publicly available anti-cancer compound by inhibiting Polo-like kinase. Previous studies revealed that GW843682X inhibited the proliferation of various tumor cell lines. In this study, the cytotoxic effect of GW843682X was investigated on cell proliferation, cell cycle and apoptosis of nasopharyngeal carcinoma 5-8F cells. Cell morphological changes were observed by inverted microscopy. Cell proliferation was tested by CCK8 assay. Cell cycle arrest and apoptosis were tested by flow cytometry. The mechanism of apoptosis was investigated by RT-PCR to determine the mRNA expression of IAP-1, IAP-2, XIAP, and survivin. GW843682X resulted in remarkable cell morphological changes with the increase of drug concentrations. CCK8 assay revealed that GW843682X inhibited the proliferation and induced apoptosis of 5-8F cells in a dose-dependent manner (IC50=62.5-125nmol/L). After treating 5-8F cells with different doses of GW843682X for 12 h, G2/M phase cells significantly increased while G0/G1 phase cells remarkably decreased. Interestingly, GW843682X significantly inhibited the mRNA expression of IAP-1 and survivin, which function as key regulators of mitosis and programmed cell death, and is overexpressed in many tumor types. The mechanism of cytotoxic effect is partially due to the inhibition of IAP gene expression. These findings indicated that GW843682X exhibited remarkable cytotoxic effects on nasopharyngeal carcinoma 5-8F cells by down-regulating IAP gene expression, suggesting that GW843682X may become a novel therapeutic agent for nasopharyngeal carcinoma.