miR-299-5p通过靶向SOX4调控胃癌细胞的增殖与凋亡

目的:探讨miR-299-5p对胃癌细胞增殖与凋亡的作用及相关机制。方法:采用RT-qPCR法检测胃癌细胞（SGC-7901、BGC-823）及正常胃黏膜上皮细胞（RGM-1）中miR-299-5p的表达差异。利用生物信息学方法预测miR-299-5p的靶基因，并使用荧光素酶报告实验验证miR-299-5p与SOX4的靶向关系。分别将miR-299-5p mimics和pcDNA3.1-SOX4转染至胃癌细胞中构建过表达模型，采用CCK-8法、流式细胞仪检测细胞增殖、凋亡情况。Western blot检测靶基因SOX4及相关蛋白（Bcl-2、Bax）表达水平。结果:胃癌细胞中miR-299-5p呈低表达，SOX4呈过表达；miR-299-5p 过表达可显著下调SOX4蛋白水平；miR-299-5p与SOX4的mRNA 3' UTR区序列配对互补，SOX4是miR-299-5p的一个潜在靶作用结合位点；miR-299-5p过表达显著降低SOX4野生型荧光素酶活性，抑制胃癌细胞增殖，诱导细胞凋亡，同时可下调SOX4、Bcl-2水平，上调Bax蛋白表达水平；上调SOX4可逆转miR-299-5p过表达对胃癌细胞的作用效果。结论:miR-299-5p在胃癌细胞中呈低表达，其通过下调SOX4表达抑制细胞增殖，诱导细胞凋亡。

miR-299-5p regulates proliferation and apoptosis of gastric cancer cells by targeting SOX4

Objective:To investigate the effect of miR-299-5p on proliferation and apoptosis of gastric cancer cells and its related mechanism.Methods:The expression difference of miR-299-5p in gastric cancer cells (SGC-7901，BGC-823) and normal gastric mucosal epithelial cells (RGM-1) was detected by RT-qPCR.Bioinformatics was used to predict the target genes of miR-299-5p，and luciferase reporting experiment was used to verify the targeting relationship between miR-299-5p and SOX4.miR-299-5p mimics and pcDNA3.1-SOX4 were transfected into gastric cancer cells to establish overexpression models，respectively，and cell proliferation and apoptosis were detected by CCK-8 method and flow cytometry.The expression levels of SOX4 and related proteins (Bcl-2 and Bax) were detected by Western blot.Results:miR-299-5p was low in gastric cancer cells and SOX4 was overexpressed.The overexpression of miR-299-5p could significantly down-regulate the SOX4 protein level.miR-299-5p was paired with and complementary to the mRNA 3' UTR sequence of SOX4，which was a potential target binding site of miR-299.miR-299-5p overexpression significantly reduced the activity of SOX4 wild-type luciferase，inhibited the proliferation of gastric cancer cells，induced apoptosis，and down-regulated the levels of SOX4 and Bcl-2，and up-regulated the expression levels of Bax protein.Upregulation of SOX4 could reverse the effect of miR-299-5p overexpression on gastric cancer cells.Conclusion:miR-299-5p is low expressed in gastric cancer cells，which inhibits cell proliferation and induces apoptosis by down-regulating the expression of SOX4.