let-7i通过调控HMGA1抑制乳腺癌细胞的生长和迁移

目的:探讨微小RNA let-7i对体外生长的人乳腺癌细胞的作用及可能的分子机制。方法:用Entranster-R4000介导let-7i mimic和阴性对照转染人乳腺癌MCF-7细胞株; CCK-8法和平板克隆实验检测转染24 h后各组细胞的生长水平;划痕试验评估转染24 h后各组细胞愈合率; Transwell试验观察转染24 h后各组细胞的侵袭数量; RT-PCR和Western blot的方法检测转染24 h后各组细胞中HMGA1的mRNA和蛋白的表达水平; RT-PCR检测乳腺癌和癌旁组织中let-7i和HMGA1的表达水平。结果:MCF-7细胞转染24 h后,let-7i mimic组的细胞增殖率和集落形成数低于阴性对照组; let-7i mimic组的细胞划痕愈合率和穿透细胞数低于阴性对照组; let-7i mimic组细胞中HMGA1 mRNA和蛋白水平均低于阴性对照组。let-7i在乳腺癌组织中表达下调,而HMGA1在乳腺癌组织中的表达上调,两者呈负相关。结论:let-7i在乳腺癌中表达下调,可能通过靶向HMGA1在乳腺癌中发挥抑癌作用。

let-7i inhibits growth and migration of breast cancer cells by targeting HMGA1

Objective:To investigate the effect of microRNA let-7i on human breast cancer cells in vitro and its possible molecular mechanism.Methods:Transfection of human breast cancer MCF-7 cell line with let-7i mimic and negative control mediated by Entranster-R4000.The growth of cell of each group was evaluated by CCK-8 assay and plate clone experiment after 24 hours of transfection.The cell healing rate of each group was calculated by scratch test and the number of cell invasion was observed by Transwell test after 24 hours of transfection.Western blot and RT-PCR was used to detect the protein and mRNA expression of HMGA1 in the cells of each group after 24 hours of transfection.The expression of let-7i and HMGA1 in breast cancer and paracancer tissues were detected by RT-PCR.Results:After 24 hours of MCF-7 cell transfection,the proliferation rate and colony formation in let-7i mimic group was lower than that in negative control group.After 24 hours of MCF-7 cell transfection,the cell healing rate of let-7i mimic group was lower than that of negative control group and the number of penetrating cells in let-7i mimic group was lower than that in negative control group.The levels of HMGA1 mRNA and protein in let-7i mimic group were lower than those in negative control group.Let-7i was down-regulated in breast cancer tissue,while HMGA1 was up-regulated in breast cancer tissue,and the expression of let-7i and HMGA1 were negatively correlated.Conclusion:let-7i is down regulated in breast cancer cells and may act as a tumor suppressor in breast cancer by targeting HMGA1.