miR-223-3p通过调控ECT2诱导非小细胞肺癌细胞凋亡的实验研究

目的：探讨miR-223-3p对非小细胞肺癌细胞增殖与凋亡的影响及其可能的作用机制。方法：选取24例非小细胞肺癌患者的癌及癌旁组织，实时定量PCR检测miR-223-3p的相对表达水平，免疫组化检测分析上皮细胞转化序列2（ECT2）蛋白的表达水平，并对两者进行相关性分析。将人非小细胞肺癌A549细胞分为正常对照组、转染对照组、miR-223-3p过表达组，其中正常对照组细胞未作任何处理，转染对照组细胞转染空质粒载体，miR-223-3p过表达组转染miR-223-3p mimics。MTT实验和平板集落形成实验检测各组细胞的增殖率，流式细胞术检测各组细胞的凋亡率，Western blot实验检测ECT2蛋白的表达水平；采用siRNA转染法沉默A549细胞中的ECT2后，检测细胞增殖及凋亡的变化。结果：miR-223-3p在癌组织中表达显著低于癌旁组织，而癌组织中ECT2蛋白表达高于癌旁组织，二者存在负相关关系（r=-0.666，P < 0.05）；与正常对照组和转染对照组细胞相比，miR-223-3p过表达组细胞的增殖率降低（P < 0.05），ECT2蛋白表达显著降低，而细胞凋亡率显著升高（P < 0.05）；沉默ECT2对细胞增殖和凋亡的影响与过表达miR-223-3p基本一致。结论：miR-223-3p可能通过负向调控ECT2的表达，进而抑制非小细胞肺癌细胞增殖并诱导其凋亡，其作用机制有待进一步研究。

miR-223-3p negatively regulated ECT2 to induce apoptosis in non-small cell lung cancer cells

OBJECTIVE： To investigate effects of miR- 223- 3p on proliferation and apoptosis of nonsmall cell lung cancer cells. METHODS： Relative expression levels of miR-223-3p were detected by realtime quantitative PCR in 24 patients with non-small cell lung cancer (NSCLC) and expression levels of epithelial transformation sequence 2 (ECT2) protein were analyzed by immunohistochemistry. Correlations between the expression levels of miR-223-3p and ECT2 were analyzed. Human NSCLC cells A549 were divided into normal control group， transfected control group and miR-223-3p over-expression group. The normal control group cells were not treated and cultured normally，and the transfected control group cells were transfected with empty plasmid vector using transfection reagents. The miR-223-3p over-expression group was transfected with miR-223-3p mimics. Proliferation rates of cells from each group were detected by the MTT and the plate colony formation assays. Apoptosis rates of cells in each group were detected by flow cytometry. Expression levels of the ECT2 protein were detected by Western blot assay. After ECT2 was knocked down by siRNA， A549 cells were divided into normal control， transfected control and ECT2 silenced groups. Then， changes of cell proliferation and apoptosis in each group were detected. RESULTS： Expressions of miR-223- 3p in cancer tissues were significantly lower than that in paracancerous tissues while expressions of ECT2 protein were higher， showing a negative correlation between them (r=- 0.666， P < 0.05). Compared with the normal control and the transfected control groups， proliferation rates of miR- 223- 3p in the over- expression group was decreased (P < 0.05)，expressions of ECT2 protein were significantly decreased，and apoptosis rates were significantly increased (P < 0.05). Effects from siRNA knockdown of ECT2 on cell proliferation and apoptosis were basically the same as that of miR- 223-3p over-expression group. CONCLUSION： Our data show that miR- 223-3p inhibited proliferation and induced apoptosis of NSCLC cells by negatively regulating the expression of ECT2.