微小RNA-202对A549细胞增殖和周期的作用及机制

目的：探讨miRNA-202对肺癌细胞A549的调控作用和可能机制。方法：应用DIANA TOOLs及KEGG数据库对miR-202进行生物信息学分析，探讨其可能参与的信号通路和潜在靶基因。通过慢病毒转染，分别上调和下调A549细胞中miR-202的表达，应用MTT法和流式细胞技术检测miR-202对细胞增殖、周期和凋亡的影响。应用qPCR和Western blot技术分别检测miR-202对其预测靶基因PIK3R3的mRNA和蛋白表达水平的调控作用。结果：生物信息学分析显示，miR-202参与的信号通路可能通过对PIK3CA的靶向调控发挥作用。功能研究表明，与阴性对照组相比，上调miR-202表达可抑制A549细胞增殖（P < 0.05），引起细胞周期G1/S期阻滞（P < 0.05），对细胞凋亡无明显影响（P > 0.05）。靶基因研究结果显示，与阴性对照组相比，上调miR-202表达可引起PIK3CA蛋白表达量下降（P < 0.05），但其mRNA的表达无显著改变（P > 0.05）。结论：miR-202可能通过对PIK3CA的负向调控影响A549细胞的增殖和周期，本研究为深入了解miRNA在肺癌中的作用与机制提供了新的线索。

Regulatory mechanism of miR-202 on proliferation of A549 lung cancer cells

OBJECTIVE:To investigate the regulatory mechanism on proliferation of miR-202 in A549 lung cancer cells.METHODS:Through the lentivirus transfection into A549 cells,up-and down-expression of miR-202 were investigated.DIANA-TOOLs and KEGG database were used to analyze the bioinformatic of miR-202 expression and to explore the signaling pathways that might be involved with potential target genes.Then,MTT assay and flow cytometry technology were applied to detect the influence of miR-202 on cell proliferation,apoptosis and cycle.RT-qPCR and Western blot methods were applied to detect the miR-202 regulation for its predicted target gene on both mRNA and protein levels.RESULTS:Bioinformatics analysis show that,miR-202 was involved in non-small cell lung cancer and other tumor-related pathways,and possibly in regulation of PIK3CA.Functional studies show that,compared with the negative control group,up-regulation of miR-202 inhibited cell proliferation (P＜0.05),caused cell cycle G1/S phase arrest (P＜0.05),but did not affect cell apoptosis (P＞0.05).Target gene study show that,compared with the control group,up-regulation of miR-202 reduced the expression of PIK3CA protein (P＜0.05),but had no effect on the expression of PIK3CA mRNA(P＞0.05).CONCLUSION:Expression of miR-202 influenced the proliferation and cycle of A549 cells through the negative regulation of PIK3CA and the study provides a new clue to the role and mechanism of miRNA in lung cancer.