【摘要】 目的 探讨miR-140-5p在低氧环境下对乳腺癌细胞功能的影响。方法 对乳腺癌细胞株MDA-MB-231进行常规培养和缺氧处理，qt-PCR检测miRNA-140-5p在细胞MDA-MB-231低氧和常氧状态下的表达水平，WB实验检测miRNA-140-5p在细胞MDA-MB-231低氧和常氧状态下的蛋白表达水平，转染miRNA-140-5p mimics,将细胞分组(常氧组、低氧组、低氧+Mock组、低氧+miRNA-140-5p mimics组),对各组细胞进行增殖、迁移、侵袭能力检测；最后，检测各组细胞中NOX4的表达情况，评估miR-140-5p与NOX4的调控关系。结果 miRNA-140-5p在细胞MDA-MB-231缺氧状态中的表达降低(P<0.05),转染miRNA-140-5p mimics表达升高。miRNA-140-5p mimics能增强细胞在低氧环境中的增殖、迁移、侵袭能力；miRNA-140-5p mimics也能增强NOX4在MDA-MB-231中的表达影响。结论 miRNA-140-5p在乳腺癌细胞MDA-MB-231缺氧状态中的表达减低，在转染Mimic之后表达升高，并且对细胞MDA-MB-231在低氧状态下的迁移、侵袭、增殖功能产生了影响，表明细胞低氧状态下miRNA-140-5p对乳腺癌细胞MDA-MB-231功能的影响可能导致了乳腺癌发生发展，并且这一机制可能是对MDA-MB-231中的NOX4诱导变化而形成的。更多还原

【Abstract】 Objective This study aims to explore the effect of miR-140-5p on the function of breast cancer cells under hypoxia. Methods The breast cancer cell line MDA-MB-231 was routinely cultured and treated with hypoxia. The expression level of miRNA-140-5p in MDA-MB-231 cells under hypoxia and normoxia was detected by qt PCR. The protein expression level of miRNA-140-5p in MDA-MB-231 cells under hypoxia and normoxia was detected by WB experiment. The cells were transfected with miRNA-140-5p mimics. The cells were divided into groups, and the cells in each group were proliferated Migration and invasion ability testing; Finally, detect the expression of NOX4 in each group of cells and evaluate the regulatory relationship between miR-140-5p and NOX4. Results The expression of miRNA-140-5p decreased in the hypoxic state of MDA-MB-231 cells(P<0.05), while the expression of miRNA-140-5p mimics increased after transfection. miRNA-140-5p mimics could enhance the proliferation, migration, and invasion ability of cells in hypoxic environments; miRNA-140-5p mimics could also enhance the expression of NOX4 in MDA-MB-231. Conclusion The expression of miRNA-140-5p in breast cancer cell MDA-MB-231 under hypoxia is reduced, and the expression of miRNA-140-5p is increased after transfection with Mimic, and it has an impact on the migration, invasion and proliferation of MDA-MB-231 under hypoxia, indicating that the impact of miRNA-140-5p on the function of breast cancer cell MDA-MB-231 under hypoxia may lead to the occurrence and development of breast cancer. And this mechanism may be formed by inducing changes in NOX4 in MDA-MB-231.更多还原