Inhibitory effect of polyphyllin Ⅰ on the proliferation of prostate cancer PC3 cells via ERK1/2/P65/DNMT1 and its molecular mechanism

ZOU Pei-liang; ZHANG Qiu-hong; ZHOU Jian-fu; LIN Rong-wu; CHEN Zhi-qiang; XIANG Song-tao

doi:10.13263/j.cnki.nja.2018.03.002

Abstract：Objective:To explore the inhibitory effect of polyphyllin Ⅰ (PP Ⅰ) on the proliferation of castration-resistant prostate cancer PC3 cells and its molecular mechanism.Methods:We cultured human prostate cancer PC3 cells in vitro and treated them with PP Ⅰ at the concentrations of 0 (blank group),0.4,0.8,1.2,1.6,2.0,and 2.4 μmol/L for 24,48,and 72 hours,respectively.Then we detected the proliferation of the cells by MTT assay,measured their apoptosis by flow cytometry,and determined the expressions of p-ERK1/2,ERK1/2,NF-κB/p65 and DNMT1 proteins as well as the level of NF-κB/p65 in the cells additionally treated with the ERK1/2 inhibitor SP600125 by Western blot.Results:Compared with the blank control group,the PP Ⅰ-treated PC3 cells showed a concentration-and time-dependent reduction of the survival rate (1.00 ± 0.00 vs 0.85 ± 0.05,P ＜ 0.01) at 0.4 μmol/L after 48 hours of intervention,concentration-dependent early apoptosis at 0.8 μmol/L (4.83 ± 0.95 vs 13.83 ± 2.97,P ＜ 0.01),time-dependent increase of the expressions of p-ERK1/2 (1.00 ± 0.00 vs 1.73 ± 0.17,P ＜ 0.01) and ERK1/2 (1.00 ± 0.00 vs 1.36 ± 0.12,P ＜ 0.01) at 2 hours,and concentration-dependent decrease of the expressions of NF-κB/p65 and DNMT1 at 1.2 μmol/L (1.00 ± 0.00vs0.78 ± 0.10 and0.63 ± 0.06,P ＜ 0.01) and 1.6 μmol/L (1.00 ± 0.00vs0.67 ±0.11 and 0.52 ± 0.09,P ＜0.01).Inhibition of ERK1/2 phosphorylation with PD98059 markedly reversed PP Ⅰ-induced decrease of the NF-κB/p65 expression as compared with that in the PP Ⅰ group (0.86 ± 0.18 vs 0.43 ± 0.09,P ＜ 0.05).Conclusion:PP Ⅰ induces the early apoptosis and suppresses the proliferation of PC3 cells,probably by activating the ERK1/2 pathway and inhibiting the expressions of the NF-κB/p65 and DNMT1 proteins.