OBJECTIVETo explore the role of the P38 signaling pathway in the apoptosis of arsenic trioxide (As2 O3)-induced androgen-independent prostate cancer PC-3 cells.

METHODSAndrogen-independent prostate cancer PC-3 cells were treated with different concentrations of As2 O3 for 24, 48 and 72 hours. The inhibitory effect of As2 O3 on the cell growth was measured by MTT, the expression of p- P38 detected by Western blot, and the rate of cell apoptosis determined by Annexin V and PI double staining before and after interfering the P38 signaling pathway by SB203580, a highly selective P38 inhibitor.

RESULTSAs2 O3 inhibited the proliferation of PC-3 cells in a concentration- and time-dependent manner, and quickly activated P38 phosphorylation, thus giving full play to its biological activities. After 24 hours of treatment with As2 O3 at the concentrations of 2, 10 and 20 micromol/L, the apoptosis rates of the PC-3 cells were (18.9 +/- 0.43), (24.7 +/- 0.29) and (49.7 +/- 1.79)%, respectively, which were reduced to (14.8 +/- 0.81), (22.1 +/- 0.51) and (39.6 +/- 1.74)% after interfering the P38 pathway with SB203580. Inhibition of the P38 pathway significantly reduced the apoptosis of the PC-3 cells induced by As2 O3 (P < 0.05).

CONCLUSIONAs2 O3 can induce the apoptosis of prostate cancer PC-3 cells by activating the P38 signaling pathway, and interfering the P38 signaling pathway can reduce their apoptosis, which suggests that the P38 signaling pathway is involved in the apoptosis of As2 O3-induced androgen-independent prostate cancer PC-3 cells.