曲古抑菌素A和紫杉醇对子宫内膜癌Ark2细胞凋亡和线粒体膜电位的影响

Effects of Trichostatin A and Paclitaxel on Apoptosis and Mitochondrial Membrane Potential of Human Endometrial Carcinoma Ark2 Cells

背景与目的:晚期子宫内膜癌患者应用现有的抗癌药物治疗预后较差,5年生存率仅为25%,为降低这类患者死亡率,需研发新的抗癌药物。组蛋白去乙酰基酶抑制剂曲古抑菌素A(Trichostatin,TSA)有望应用于临床各种恶性肿瘤的治疗,与传统的抗肿瘤药物联用可以提高肿瘤患者的生存率。本实验探讨TSA和紫杉醇(paclitaxel,PTX)对人子宫内膜癌Ark2细胞凋亡的影响及其机制。方法:Ark2细胞培养于RPMI-1640培养液中,应用TSA、PTX单独或者联合干预,Annexin V法结合Hoechst33258染色法检测Ark2细胞凋亡;Western blot检测其凋亡信号通路中Caspase-9活化及多聚ADP核糖聚合酶(Poly ADP-ribose polymerase,PARP)裂解情况,以及微管乙酰化的表达及微管稳定性。MitoTracker red法检测其线粒体膜电位。结果:流式细胞仪检测显示,1.5nmol/L PTX联合25nmol/L TSA处理Ark2细胞3d后,可见45.2%的细胞凋亡,明显高于单用1.5nmol/L PTX或25nmol/L TSA组的细胞凋亡率(分别为14.1%、11.2%)。Hoechst33258染色法检测结果与流式细胞仪检测结果一致。TSA和PTX联用组PARP、Caspase-9裂解较单用PTX或TSA明显增加(P<0.05)。Western blot和免疫荧光分析证明PTX和TSA可诱导微管蛋白乙酰化,联合用药后微管蛋白乙酰化明显增加,微管稳定性增强。PTX和TXA联合组细胞线粒体膜电消失较单独用药组明显,两药合用具有协同作用(q=2.54)。结论:TSA和PTX有促进Ark2细胞凋亡的作用,去乙酰化酶抑制剂导致的非组蛋白乙酰化和线粒体膜电位的消失是其可能的抗肿瘤机制。

BACKGROUND ＆ OBJECTIVE： Patients suffered from advanced endometrial cancer have poor prognosis. The five-year survival is only 25%. Histone deacetylase inhibitors have shown promise in the treatment for a variety of malignancies. In combination with traditional cytotoxic chemotherapy, histone deacetylase inhibitors can enhance the survival rate of cancer patients. This study was to investigate the effect and mechanism of trichostatin A （TSA）, a histone deacetylase inhibitor, combined with paclitaxel （PTX） on the apoptosis of human endometrial carcinoma cell line Ark2. METHODS, Ark2 cells were cultured in RPMI-1640 and treated with PTX alone, TSA alone or the two drugs in combination. Cell apoptosis was detected using Annexin V and Hoechst staining; perturbation of mitochondrial membrane potential was detected using MitoTracker red Poly （ADP-ribose） polymerase; caspase-9 degradation products and tubulin acetylation were detected by Western blot. RESULTS, Results of Annexin V showed that PTX （1.5 nmol/L） plus TSA （25 nmol/L） induced a significantly higher apoptotic rate （45.2%） than PTX alone （14.1%） or TSA alone （11.2%） did in Ark2 cells after drug treatment for three days. The results of Hoechst staining and Annexin V were consistent. A loss of mitochondrial membrane potential could activate the apoptotic cascade. Cleavages of PARP and caspase-9 were significantly apparent in PTX plus TSA group than in PTX group or TSA group （P〈0.05）. PTX and TSA could induce tubulin acetylation. PTX in combination with TSA increased acetylated tublins and microtubule stability compared with either drug alone. The loss of mitochondrial membrane potential was more dramatic in the drug combination group than the single drug group. The effects of TSA and PTX were synergistic （q=2.54）. CONCLUSION, TSA and PTX could induce apoptosis of Ark2 cells, which may be through the loss of mitochondrial membrane potential and acetylation of non-histone proteins induced by histone deacetylase inhibitors.