抑制ERK增强白血病和卵巢癌耐药细胞系化疗敏感性

为了研究细胞外调节蛋白激酶(extracelluar regulated protein kinases，ERK)和端粒酶在白血病和卵巢癌细胞耐药中的作用，应用流式细胞术检测细胞凋亡率，应用端粒重复序列扩增法(TRAP)和生物发光分析法去除检测端粒酶活性，应用Weestern blot法检测磷酸化ERK1/2蛋白(ERK1和ERK2)表达水平。结果表明：ERK激酶1(MEK1)特异性抑制剂PD98059能增强HL-60／E6细胞对三尖杉酯碱(HRT)的敏感性，PD98059也能增强COCl／DDP细胞对顺铂(DDP)的敏感性。PD98059与化疗药物HRT和DDP均可以降低细胞内磷酸化ERK表达，抑制端粒酶活性，但PD98059与化疗药物的联合作用明显强于其各自的单独作用。结论：通过阻抑ERK通路，降低磷酸化ERK1/2蛋白表达水平，进而下调端粒酶活性，可以达到增强白血病和卵巢癌耐药细胞对HRT或DDP敏感性的目的。

To Inhibit ERK for Enhancing Chemotherapy Sensitivity of Drug-resistance Cell Lines of Leukemia and Ovarian Carcinoma

The aim was to study the roles of extracelluar regulated protein kinases (ERK) and telomerase activity in drug resistance of human leukemia and ovarian carcinoma cells. Flow cytometry was used to analyze apoptosis rate. Telomere repeat amplification protocol (TRAP) and bioluminescence analysis method were used for detection of telomerase activity. The phosphorylated ERK 1/2 protein expression was observed by Western blot method. The results showed that the specific inhibitor PD98059 of ERK kinase 1 (MEK 1) enhanced the sensitivity of HL 60/E6 leukemia cell lines to harringtonine (HRT) or COC1/DDP ovarian carcinoma cell lines to cis dichlorodiamine platinum (DDP). Both PD98059 and chemotherapy drugs HRT and DDP reduced the phosphorylated ERK 1 and ERK 2 protein expression level, and down regulated the telomerase activity. The sole action of each was inferior to the combination action of PD98059 and HRT or DDP. In conclusion, ERK and telomerase serve a function to some extent in drug resistance of leukemia and ovarian carcinoma cells. The inhibition of ERK signal transduction pathways led to reduction of phosphorylated ERK 1 and ERK 2 protein expression level, and successionally down regulated the telomerase activity. The final result was to enhance the sensitivity of HL 60/E6 to HRT or COC1/DDP to DDP.