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目的:研究miR-133b对结肠癌细胞(SW620细胞)凋亡及放射敏感性影响并探讨其机制。方法:采用脂质体法转染miR-con组(转染miR-con)、miR-133b组(转染miR-133b mimics)、si-con组(转染si-con)和si-HER-2组(转染si-HER-2) SW620细胞，然后进行0、2、4、6、8 Gy照射。使用qRT-PCR、Western blot、流式细胞术、克隆形成实验和双荧光素酶报告基因实验分别检测各组细胞中miR-133b表达、HER-2蛋白表达、细胞凋亡、细胞存活分数和细胞荧光活性。结果:与照射前相比，照后SW620细胞中miR-133b表达降低(n P<0.05)，HER-2表达升高(n P<0.05)。过表达miR-133b、敲减HER-2均可降低SW620细胞存活分数(n P<0.05)，促进细胞凋亡(n P<0.05)。miR-133b可抑制野生型HER-2细胞荧光活性(n P<0.05)，且可负向调控HER-2蛋白表达。n 结论:miR-133b可抑制SW620细胞存活，促进细胞凋亡，增强放射敏感性，其机制可能与靶向HER-2有关。“,”Objective:To evaluate the effect of miR-133b on the apoptosis and radiosensitivity of colon cancer cell line (SW620 cells), and to explore its mechanism.Methods:SW620 cells were transfected with miR-con (miR-con group), miR-133b mimics (miR-133b group), si-con (si-con group) and si-HER-2(si-HER-2 group) by the liposome method, and then irradiated with 0, 2, 4, 6, 8 Gy. The miR-133b protein expression, HER-2 protein expression, apoptosis, cell survival fraction and cytofluoroactivity in each group were evaluated by qRT-PCR, Western blot, flow cytometry, colony formation assay and dual luciferase reporter gene assay, respectively.Results:Compared with the pre-irradiation group, the expression level of miR-133b was significantly down-regulated (n P<0.05), whereas that of HER-2 was significantly up-regulated in SW620 cells after irradiation (n P<0.05). Overexpression of miR-133b and knockdown of HER-2 remarkably reduced the survival fraction (bothn P<0.05), and significantly promoted the apoptosis of SW620 cells (n P<0.05). miR-133b could considerably inhibit the fluorescent activity of wild-type HER-2 cells (n P<0.05) and negatively regulate the expression of HER-2 protein.n Conclusion:miR-133b can inhibit the survival of colon cancer cells, promote the apoptosis and enhance the sensitivity of radiotherapy probably via the mechanism of targeting HER-2.