目的：探讨hsa-miR-99b在胃腺癌细胞系的表达及其影响胃腺癌细胞系增殖和迁移的潜在作用机制。方法: Real-time PCR检测miR-99b在人胃上皮细胞系GES-1和人胃腺癌细胞系SGC-7901、BGC-823、MGC-803中的表达。用人工合成的miR-99b模拟物转染SGC-7901细胞构建过表达miR-996细胞系，转染对照模拟物作为对照组，CCK-8法检测过表达miR-99b的SGC-7901细胞的增殖情况，Transwell 法检测SGC-7901细胞系的迁移情况，Western blotting检测SGC-7901细胞系中哺乳动物雷帕霉素靶蛋白（mammalian target of rapamycin，mTOR）的表达情况。结果:miR-99b在胃腺癌细胞系中的表达水平显著低于胃上皮细胞系，其中以SCG-7901细胞最甚。转染miR-99b模拟物48 h后，实验组SCG-7901细胞增殖能力低于对照组（020±0.00 vs 0.27±0.02，P＜0.05）；与转染对照模拟物的细胞相比，转染24 h后，实验组SCG-7901穿膜细胞数低于对照组\[（226.67±25.17) vs (523.33±25.17)个，P＜0.05\]。miR-99b可下调人胃腺癌细胞系SGC-7901中mTOR蛋白的表达。结论： miR-99b在胃腺癌细胞系中的表达明显下调，miR-99b抑制人胃腺癌细胞系SGC-7901增殖和迁移的作用可能与下调mTOR表达有关。

Objective:To investigate the expression of has miR-99b in gastric adenocarcinoma cell lines and its potential mechanism of affecting proliferation and migration of the gastric adenocarcinoma cell lines. Methods: Real-time PCR was performed to detect the expressions of miR-99b in human gastric epithelial cell line GES-1 and human gastric adenocarcinoma cell line (SGC7901, BGC823 and MGC-803). The synthesized miR-99b mimics were transfected into the SGC-7901 cells to constract a overexpressed cell line, and scramble mimics were transfected into the same cells as control group. Then proliferation and migration of the SGC-7901 cell lines which overexpressed miR-99b were measured by CCK-8 assay and transwell assay; expression level of mTOR (mammalian target of rapamycin) protein was determined by Western blotting. Results: The expression levels of miR-99b in the gastric adenocarcinoma cell lines, especially in the SGC-7901 cell line, were significantly lower than those in the human gastric epithelial cell line. After transfectio of the miR-99b mimics for 48 h, proliferation ability of the SGC-7901 cell in experiment group was lower than that of control group（0.20±0.00 vs 0.27±0.02，P<0.05）. Compared to the cell line transfected with the scramble mimics, the experiment group showed a significant reduction in number of transmembrane cells（226.27±25.17 vs 523.33±25.17，P<005）after the transfection for 24 h. miR-99b can downregulate the expression of mTOR protein in the human gastric adenocarcinoma cell line SGC-7901. Conclusion:The expression of miR-99b in gastric adenocarcinoma cell lines was obviously down regulated, inhibition effect of miR-99b on proliferation and migration of the human gastric adenocarcinoma cell line SGC-7901 might be related with down-regulated expression of mTOR.

国家自然科学基金资助项目(No. 81270465)；成都市卫生局计划资助项目(No. 2013059)