中文摘要：

目的：明确miR-30b对结直肠癌细胞侵袭和迁移潜能的影响。方法：RT-qPCR检测20对配对结直肠癌组织标本中miR-30b的表达；Transwell和划痕实验检测过表达和抑制miR-30b后结直肠癌细胞侵袭和迁移潜能的改变；应用生物信息学方法预测miR-30b的作用靶点；Western Blot及双荧光素酶报告基因实验验证过表达和抑制miR-30b后靶点Snail和EMT（epithelial mesenchymal transition）标志物的表达情况。结果：癌组织中miR-30b表达水平明显低于正常肠黏膜组织；Transwell及划痕实验结果显示过表达miR-30b后结直肠癌细胞的侵袭迁移能力降低，抑制miR-30b后侵袭迁移能力增强；生物信息学预测结果显示miR-30b能够作用于Snail 3＇-UTR，双荧光素酶检测结果进一步证实miR-30b能够作用于Snail 3＇-UTR；Western Blot结果显示过表达miR-30b后Snail的表达下降，EMT标志物Vimentin表达下降和E-cadherin表达升高，而抑制miR-30b后结果相反。结论：miR-30b在结直肠癌中表达水平下降，并通过靶向Snail调节结直肠癌细胞的侵袭和迁移。

英文摘要：

Objective：To determine the function of miR-30b in the metastasis of colorectal cancer cells. Methods：RT-qPCR was performed to test miR-30b expression in 20 fresh primary colorectal cancer tissues and their corresponding adjacent tissues. Transwell and wound healing assays were performed to test the invasion and migration of colorectal cancer cells after miR-30b overexpression or inhibition. Bioinformatics assay was performed to predict miR-30b targets. Western Blot and Dual Luciferase reporter assay were performed to test the expressions of Snail and downstream target genes in colorectal cancer cells. Results：The results reveal that miR-30b expression decreased in cancer tissues compared with normal tissues. Transwell and wound healing assays reveal that miR-30b overex-pression inhibited cell invasion and migration, whereas miR-30b inhibition promoted the invasion and migration of colorectal cancer cells. Bioinformatics analyses reveal that miR-30b targets the 3＇-UTR of Snail. Dual Luciferase reporter assay confirms that miR-30b affects the 3＇-UTR of Snail. Western Blot analyses show that Snail and Vimentin expressions were significantly downregulated, whereas E-cadherin expression obviously increased after miR-30b overexpression. However, Snail and Vimentin expressions increased, but E-cadherin expression decreased after miR-30b inhibition. Conclusion：The miR-30b gene is downregulated in colorectal cancer tissues. The miR-30b protein may be important in the regulation of cell invasion and migration by targeting Snail in colorectal cancer cells.