OBJECTIVETo evaluate the effects of methylation inhibitor 5-Aza-2'-Deoxycytidine (5-aza-2dc) and docetaxel (DT), alone or in combination, on the proliferation, migration, apoptosis and cell cycles of the human prostate cancer cell line PC3, and to investigate the possible mechanisms of these two drugs acting on prostate cancer in vitro.

METHODSFour groups were designed in this experiment: control, 5-aza-2dc, DT, and 5-aza-2dc + DT. The inhibitory effect of 5-aza-2dc and/or DT on the proliferation, migration and invasiveness of PC3 cells was detected by MTT, wound healing assay and cell migration assay, respectively. The apoptosis of the PC3 cells and its relationship with cell cycles were determined by Annexin V-FITC/PI assay and flow cytometry.

RESULTS5-aza-2dc and/or DT significantly increased the inhibition rate of the PC3 cells, decreased their migration distance and reduced the number of the cells that invaded the lower chamber, most significantly in the 5-aza-2dc + DT group (P < 0.05). The cell apoptosis rates of the control, 5-aza-2dc, DT and 5-aza-2dc + DT groups were (10.65 +/- 0.39)%, (16.60 +/- 0.67)%, (17.95 +/- 1.08)% and (22.98 +/- 1.18)%, respectively, with the most significant increase in the combination group (P < 0.05). Combined medication of 5-aza-2dc and DT remarkably reduced the number of cells in the G0/G1 phase, and increased that in the G2/M phase (P < 0.05).

CONCLUSION5-aza-2dc and DT, either alone or in combination, can significantly inhibit the proliferation, migration and invasiveness of PC3 cells in vitro, as well as induce their apoptosis and arrest their cell cycles in the G2/M phase, with even more significant effect when used in combination than applied alone.