MiR-138对MCF-7细胞端粒酶活性及端粒稳定性的调控作用

 目的 研究MiR-138通过HTERT作为下游靶基因，对人乳腺癌MCF-7细胞端粒酶活性的调控作用及端粒稳定性的影响。方法 在人乳腺癌MCF-7细胞中瞬时转染MiR-138 模拟物，用MTT法检测细胞增殖活性，并于转染后48h，用实时定量RT-PCR检测端粒酶催化亚单位HTERT表达、TRAP Assay检测端粒酶活性，同时对细胞进行53BP1 抗体免疫荧光染色及端粒的FISH染色。结果 转染后48h，MiR-138模拟物处理的MCF-7细胞HTERT表达水平比对照细胞降低2.18倍(2-△△Ct)，端粒酶活性比对照细胞降低2.69倍，53BP1聚集形成的凝集点（Foci），部分与端粒位点重合，比率达到20.62%±1.55% 。结论 MiR-138以HTERT作为下游靶分子，调控MCF-7细胞端粒酶活性，影响细胞端粒稳定性。

The regulation of telomerase activity and telomere stability by MiR-138 in MCF-7 cells

Objective To study the regulation of telomerase activity of MiR-138 through targeting HTERT as the downstream molecular, and its effect on telomere stability in breast cancer cell line MCF-7. Methods MiR-138 mimics were transiently transfected into breast cancer cell line MCF-7. MTT method was applied for detecting the effect on cell proliferation. The HTERT expression level of the cells was detected by real-time RT-PCR and telomerase activity was checked by TRAP Assay 48h after transfection. Meanwhile, the cells were checked simultaneously by 53BP1 antibody immunofluorescent dyeing and telomere FISH dyeing. Results The HTERT expression level of MCF-7 cells treated with MiR-138 was repressed by 2.18 folds (2-△△Ct) when compared with the control cells 48h after transfection. Telomerase activity was also decreased by 2.69 folds when compare with the control cells. 53BP1congregated into many Foci and co-localized with the telomere spots at a percentage of 20.62%±1.55%. Conclusion MiR-138 can regulate telomerase activity in MCF-7 cells by targeting HTERT as the downstream molecular, and affects the telomere stability as well.