miR-29a在乳腺癌组织中的表达及其对乳腺癌细胞增殖和迁移的影响

Expression of miR-29a in breast cancer tissue and its effects on the proliferation and migration of breast cancer cells

目的检测miR-29a在乳腺癌组织中的表达水平并探讨其对人乳腺癌细胞增殖和迁移的影响。方法用荧光定量RTPCR检测乳腺癌组织及癌旁组织中miR-29a的表达水平;用脂质体法将miR-29amimic及miR-29a inhibitor分别转染乳腺癌细胞系MDA-MB-231,通过MTT实验和Transwell实验观察miR-29a对MDA-MB-231细胞增殖和迁移能力的影响;miRanda软件预测miR-29a的靶基因,westernblot验证其表达结果。结果荧光定量RT-PCR检测结果表明,与癌旁组织(2.17±0.89)比较,miR-29a在乳腺癌组织(5.65±1.45)中的表达水平上调(t=3.94,P<0.01);MTT实验和Transwell实验结果显示,与mimics阴性对照组[(106.36±5.15)%,(216.70±7.20)个]相比,miR-29amimics组[(133.32±6.31)%,(294.30±8.60)个]乳腺癌细胞的增殖和迁移能力增加(t分别为3.36和6.85,P均<0.01);与inhibitor阴性对照组[(105.35±3.42)%,(240.30±9.50)个]相比,miR-29a inhibitor组[(66.63±3.82)%,(156.30±7.80)个]乳腺癌细胞的增殖和迁移能力降低(t分别为8.18和6.81,P均<0.01)。miRanda软件预测人第10号染色体缺失的同源性磷酸酶-张力蛋白基因(PTEN)可能为miR-29a的靶基因。western blot结果显示,与mimics阴性对照组(0.55±0.01)相比,乳腺癌细胞转染miR-29amimic后,其PTEN蛋白质的表达水平(0.22±0.01)下调(t=14.29,P<0.01);与inhibitor阴性对照组(0.49±0.02)相比,转染miR-29a inhibitor后,PTEN蛋白质的表达水平(1.25±0.02)上调(t=19.39,P<0.01)。结论miR-29a在乳腺癌组织中的表达水平增高,并可能通过下调PTEN蛋白的表达促进乳腺癌细胞的增殖和转移。

Objective To investigate the expression level of miR-29a in breast cancer tissue and its effects on the proliferation and mi- gration of breast cancer cells. Methods The expression levels of miR-29a in breast cancer tissue and adjacent tissue were detected by real-time polymerase chain reaction. The miR-29a mimics and miR-29a inhibitor were transfected into human breast cancer MDA-MB- 231 cells by the lipofection method, and the effects of miR-29a on the proliferation and migration of MDA-MB-231 cells were evaluated by MTT and Transwell assays, respectively. The target genes of miR-29a were predicted with the miranda software, and their expres- sion levels were detected by western blot. Results The expression level of miR-29a in breast cancer tissue was significantly higher than that in adjacent tissue （5.65 ±1.45 vs 2.17 ± 0.89, t = 3.94, P 〈 0.01 ）. After the MDA-MB-231 cells were transfeeted with miR-29a mimics, their proliferation and migration ability increased significantly compared with the mimics negative control group [（133.32±6.31）% vs （106.36±5.15）%, t=3.36, P〈0.01; 294.30±8.60 vs 216.70±7.20, t=6.85, P〈0.01]. After the MDA-MB-231 cells were transfeeted with miR-29a inhibitor, their proliferation and migration ability decreased significantly com- pared with the inhibitor negative control group [ （66.63 ± 3.82） % vs （ 105.35 ± 3.42） % , t = 8.18, P 〈 0.01 ; 156.30 ± 7.80 vs 240.30 ± 9.50, t = 6.81, P 〈 0.01 ]. The miRanda software predicted that phosphatase and tensin homolog deleted on chromosome 10 gene （PTEN） might be the target gene of miR-29a. After the MDA-MB-231 cells were transfected with miR-29a mimics, the expres- sion level of PTEN protein in these cells decreased significantly compared with the mimics negative control group （0.22 ± 0.01 vs 0.55 ± 0.01, t = 14.29, P 〈 0. O1 ）. After the MDA-MB-231 cells were transfected with miR-29a inhibitor, the expression level of PTEN in these cells increased significantly compared with the inhibitor negative control group （ 1.25± 0.02 vs 0.49 ± 0.02, t = 19.39, P 〈 0.01 ）. Conclnsion The expression level of miR-29a increases in breast cancer tissue and miR-29a may promote the proliferation and migration of breast cancer ceils by the down-regulation of trFEN protein expression.