Influence of human epithelial ovarian cancer HO-8910 cells with modified survivin gene on the cell cycle distribution and chemosensitivity

Abstract

To study the influence of survivin mutant-T34A (survivin(T34A)) and survivin deletant-N-terminal 8 amino acids residues (survivin(N-8AA)) on the cell cycle distribution and chemosensitivity in human ovarian cancer HO-8910 cells for explorating the roles of modified survivin-mediated apoptosis induced by chemotherapeutic agents and possible signaling pathways involved. pcDNA3.1 plasmid contained wild-type, survivin(T34A) and survivin(N-8AA) genes were transfected into HO-8910 cells, respectively, the control groups were HO-8910 cells transfected with pcDNA3.1 plasmids. The expression of mRNA was examined by reverse transcription(RT) PCR and identified by DNA sequencing; the cell cycles were determined by flow cytometer analysis (FCM); the growth inhibitions rate of cisplatin (DDP), paclitaxel (PTX) and LY294002 on the transfected cells were determined using methyl thiazolyl tetrazolium (MTT) assay. (1) The RT-PCR procedures and genome sequences showed that the survivin mRNA were expressed stable in the transfected HO-8910 cells. (2) There was lower percent of G(0)/G(1) phase cells in SN-HO-8910 cells than that in PC-HO-8910 cells (44.72% vs. 49.64%, P < 0.05); while higher percentage of G(2)/M phase and S phase cells (1.06% and 54.22% vs. 0.56% and 49.80%, P < 0.05). There was lower the G(2)/M phase and S phase cells in M-HO-8910 cells 0.16% and 36.33%, than that in PC-HO-8910 cells (P < 0.05); while higher percentage of G(0)/G(1) phase cells (63.51%, P < 0.05). G(0)/G(1), G(2)/M and S phase cells in Sur-HO-8910 cells were 54.46%, 0.62% and 44.92%, and there were not significantly difference (P > 0.05), compared to those in PC-HO-8910 cells. (3) The inhibitory concentration (IC(50)) of DDP and PTX were higher in Sur-HO-8910 cells than those in control cells [(20.4 ± 6.1) vs. (14.4 ± 3.9) µmol/L, (36.7 ± 4.0) vs. (28.6 ± 3.6) µmol/L; all P < 0.05]. The IC(50) of DDP and LY294002 in SN-HO-8910 cells were lower than those in control cells [(7.6 ± 1.0) vs. (14.4 ± 3.9) µmol/L, (13.2 ± 4.0) vs. (41.0 ± 7.9) µmol/L; all P < 0.01]. The IC(50) of PTX [(37.9 ± 4.8) µmol/L] in SN-HO-8910 cells were higher than that in control cells (P < 0.05). The IC(50) of DDP in M-HO-8910 cells [(9.9 ± 1.2) µmol/L] were lower than that in control cells (P < 0.05), and the IC(50) of LY294002 in M-HO-8910 cells [(66.9 ± 4.8) µmol/L] higher than that in control cells (P < 0.01). The changes of cells cycle distribution caused by survivin(T34A) or survivin(N-8AA) enhanced the G(2)/M cell cycle-dependent chemosensitivity of PTX. Compared to survivin(T34A), survivin(N-8AA) preferentially to mediate the cytotoxicity of DDP and LY294002, suggesting that it may be related to the cell cycle-dependence of survivin function and to blockage of the formation of its active dimer.