结直肠癌中miR-182-5p通过靶向Tiam1抑制肿瘤血管新生

目的:探讨结直肠癌中miR-182-5p是否可以通过靶向Tiam1抑制肿瘤血管新生。方法:选取人正常结肠上皮细胞与结直肠癌细胞，用qPCR检测细胞系中miR-182-5p和Tiam1 mRNA的表达。将对照mimics过表达载体、miR-182-5p mimics过表达载体、对照siRNA过表达载体、Tiam1 siRNA过表达载体及Tiam1过表达载体分别转染至HT-29细胞中，用双荧光素酶报告基因实验验证miR-182-5p与Tiam1 3'UTR的靶向关系，用工程化肿瘤细胞上清培养人脐静脉内皮细胞（HUVEC），通过划痕愈合实验及小管生成实验分别检测细胞的迁移及小管生成能力，用Western blot检测相关蛋白的表达，并通过小鼠体内移植瘤模型检测血管新生。结果:miR-182-5p在HT-29细胞中显著低表达（P＜0.01），而Tiam1在HT-29细胞中显著高表达（P＜0.001），且Tiam1是miR-182-5p的靶标。迁移实验结果表明，转染miR-182-5p mimics的HT-29细胞上清可以抑制HUVEC的迁移能力（P＜0.01），Tiam1 基因沉默的HT-29细胞上清也可以抑制HUVEC的迁移能力（P＜0.001）。小管生成及小鼠体内实验表明，过表达miR-182-5p及沉默Tiam1可以有效抑制肿瘤血管生成（P＜0.01）。结论:miR-182-5p可以靶向Tiam1，通过抑制Tiam1的表达水平，从而抑制结直肠癌中的血管新生。

miR-182-5p inhibits angiogenesis by targeting Tiam1 in colorectal cancer

Objective:To investigate whether miR-182-5 p can inhibit angiogenesis by targeting Tiam1 in colorectal cancer.Methods:Human normal colonic epithelial cells and colorectal cancer cells were selected and the expression of miR-182-5 p and Tiam1 mRNA in the cell line was detected by qPCR.The control mimics overexpression vector,miR-182-5 p mimics overexpression vector,siRNA control overexpression vector,Tiam1 siRNA overexpression vector and Tiam1 overexpression vector were transfected into HT-29 cells.The targeting relationship between miR-182-5 p and Tiam1 3’ UTR was verified by luciferase reporter assay.HUVEC,cultured in the supernatant of engineering tumor cells was used to detect the ability of cell migration and tubule formation by wound-healing assay and tube formation assay,respectively.The expression of related proteins was detected by Western blot,and angiogenesis was detected by tumor xenograft model in vivo.Results:The results showed that the expression of miR-182-5 p was significantly reduced in HT-29 cells(P<0.01),while the expression of Tiam1 was significantly improved in HT-29(P<0.001),and Tiam1 was the target of miR-182-5 p.The results of migration assay showed that the supernatant of HT-29 cells transfected with miR-182-5 p mimics could inhibit the migration ability of HUVEC(P<0.01),and the supernatant of HT-29 cells silenced by Tiam1 gene could also inhibit the migration ability of HUVEC(P<0.001).Tubule formation and in vivo experiments showed that overexpression miR-182-5 p and inhibition of Tiam1 can effectively inhibit tumor angiogenesis(P<0.01).Conclusion:miR-182-5 p can target Tiam1,and inhibit angiogenesis in colorectal cancer by inhibiting the expression of Tiam1.