OBJECTIVETo investigate the inhibitory effect of polypeptide K237 on the proliferation of human hormone refractory prostate cancer cell line PC-3M and its possible mechanism.

METHODSPC-3M cells were divided into three experimental groups and a control, treated with polypeptide K237 at the concentration of 50, 100, 200 and 0 micromol/L, respectively, for 48 hours. The effects of K237 on the proliferation of different groups of the PC-3M cells were analyzed by MTF, and the mRNA expression levels of bax and bcl-2 were detected by RT-PCR.

RESULTSAfter polypeptide K237 treatment, the PC-3M cells became round, small and less transparent in cytoplasm, and some shed and suspended in the culture medium. The growth inhibition rates of the PC-3M cells were (12.6 +/- 0.95)%, (17.8 +/- 0.99)% and (27.2 +/- 1.12)% in the 50, 100 and 200 micromol/L concentration groups. RT-PCR analysis showed that the bax/beta-actin values of the 50, 100, 200 and 0 micromol/L groups were 0.919 +/- 0.071, 0.971 +/- 0.083, 0.992 +/- 0.102 and 0.889 +/- 0.067, and the bcl-2/beta-actin values of the four groups were 0.896 +/- 0.085, 0.791 +/- 0.084, 0.764 +/- 0.702 and 0.922 +/- 0.097, respectively, both with significant differences between the experimental and the control groups (P < 0.01). The mRNA expression of bax was upregulated and that of bcl-2 downregulated in a dose-dependent manner.

CONCLUSIONPolypeptide K237 may induce apoptosis of PC-3M cells by affecting the expressions of bax and bcl-2, and thus suppress the proliferation of prostate cancer cells.