DAC和顺铂在前列腺癌细胞株中协同作用的实验研究

Synergy of 5-aza-2'-deoxycytidine and cisplatin in prostate cancer cell lines

目的探讨DNA甲基转移酶抑制剂5-aza-2'-deoxycytidine(DAC)与顺铂(CDDP)在前列腺癌细胞中的协同抑制作用。方法采用WST-1法研究DAC和CDDP对4种前列腺癌细胞株的毒性作用,Isobolographic分析检验二者的协同作用。应用流式细胞仪分析联合作用在细胞凋亡诱导和细胞周期捕获中的作用,通过caspase活性和PCNA蛋白表达研究DAC和CDDP在前列腺癌中的协同作用机制。结果DAC能够明显增加前列腺癌细胞对CDDP的敏感性,在所有前列腺癌细胞株中DAC和CDDP均具有协同作用。DAC可诱导G2/M期细胞周期捕获,而CDDP通过诱导凋亡(subG1期)和G2/M期捕获两方面抑制细胞生长。DAC可增强CDDP介导的caspase活性升高和PCNA表达的下调,导致subG1期和G2/M期细胞的增加。结论DAC和CDDP在雄激素依赖和非依赖性前列腺癌细胞株中均具有协同作用,二者联合可改善前列腺癌预后,值得临床推广。

Objective To investigate the effect of 5 - aza - 2＇- deoxycytidine（DAC） ,a DNA methyltransferase inhibitor on prostate carcinoma（PC） cell lines and to analyse the synergistic growth suppression on PC cells by the combination of DAC and cisplatin （CDDP）. Methods The cytotoxicity of DAC and chemotherapeutic agents against four PC cell lines was measured using the WST - 1 assay,and the synergy of DAC and these agents was analyzed by isobolographic analysis. The effects of each single agent or the combined treatments on apoptosis induction and cell cycle arrest were analyzed by flow cytometric analysis. Caspase activity and PCNA expression were also investigated to clarify the mechanism of the synergistic actions against PC of DAC and chemotherapeutic agents. Results DAC could significantly increase the susceptibility of PC cells to CDDP and paelitaxel（PTX）. Synergistic growth suppression by DAC and CDDP existed in all tested PC cell lines. DAC inhibited proliferation by inducing G2/M cell cycle arrest,while CDDP could inhibit proliferation by inducing both apoptosis and G2/M arrest. DAC enhanced the CDDP - induced up - regulation of easpase activity and PCNA expression,resulting in an increase of cells in subG1 and G2/M phases. Conclusions The synergy of DAC and CDDP against PC suggests that combined chemotherapy of them may be a new strategy to improve the clinical response rate of prostate carcinoma.