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目的:探讨miR-29a调控共刺激分子B7-H3在脑胶质瘤中的表达及其对脑胶质瘤细胞侵袭能力的影响。方法:通过Real-time PCR检测miR-29a和B7-H3在正常脑组织、脑胶质瘤组织及人胶质瘤细胞株U87中的表达,并利用脂质体将miR-29a的模拟物(mimics)和抑制剂(inhibitors)转入U87细胞,流式术验证miR-29a对B7-H3表达的调节效果;采用CCK-8和Transwell实验观察miR-29a对U87细胞的增殖和侵袭能力的影响,并通过流式术分析miR-29a干预前后U87细胞上与细胞侵袭相关的化学趋化因子的表达变化,以miRtarbase等软件预测miR-29a与CXCR4的结合能力。结果:胶质瘤组织及细胞株中miR-29a低表达而B7-H3 mRNA高表达,且均与瘤组织病理分级相关。转染miR-29a mimics可以有效下调U87细胞中B7-H3 mRNA的表达。转染miR-29a mimics可以显著抑制U87细胞的侵袭能力(P<0.05),但对细胞增殖并无显著影响。miR-29a过表达可同时下调U87细胞中CXCR4的表达,但软件分析CXCR4基因上并不存在miR-29a的结合位点。结论:miR-29a可有效下调B7-H3分子的表达,进而抑制脑胶质瘤细胞的侵袭能力,其作用机制可能与CXCR4途径相关。
Objective: To investigate the expression of miR-29a costimulatory molecule B7-H3 in glioma and its effect on glioma cell invasiveness. Methods: Real-time PCR was used to detect the expression of miR-29a and B7-H3 in normal brain tissue, glioma tissue and human glioma cell line U87. The miR-29a mimics mimics and inhibitors were transfected into U87 cells to verify the regulatory effect of miR-29a on B7-H3 expression. The effects of miR-29a on the proliferation and invasion of U87 cells were examined by CCK-8 and Transwell assays The expression of chemotactic factor related to cell invasion on U87 cells before and after miR-29a intervention was analyzed by flow cytometry. The miR-29a and CXCR4 binding ability were predicted by miRtarbase software. Results: miR-29a and B7-H3 mRNA were highly expressed in glioma tissues and cell lines, and both were correlated with histological grade. Transfection of miR-29a mimics effectively down-regulated B7-H3 mRNA expression in U87 cells. Transfection of miR-29a mimics significantly inhibited the invasiveness of U87 cells (P <0.05), but had no significant effect on cell proliferation. miR-29a overexpression downregulated CXCR4 expression in U87 cells at the same time, but there was no miR-29a binding site in software analysis of CXCR4 gene. Conclusion: miR-29a can effectively down-regulate the expression of B7-H3 and thus inhibit the invasiveness of glioma cells. Its mechanism may be related to the CXCR4 pathway.