Analysis Of Has-miR-34a Expression In Human Breast Cancer And Its Effects On The Proliferation,Migration And Invasion Of Breast Cancer Cell Lines

ObjectiveTo investigate the expression of miR-34a in human breast cancer tissues and cell lines and its effections on the breast cancer cell lines proliferation, invasion, metastasis through predicting the possible targets to provide theoretical basis for the deep understanding of the role which miR-34a play in breast cancer occurrence and development.Methods1.Use the real-time PCR to detect the different expression of miR-34a in20human breast cancer tissues and normal tissues(distance>5cm away from cancer tissues edge), also in the breast cancer cell line MDA-MB-231, MCF-7and normal breast epithelial cell line MCF-10A.2.MiR-34a mimic and miR-NC were transfected into cells by liposome transfect technique, then we used MTT to examine the changes of cell’s proliferation, then used Transwell to detected cell invasion and migration ability. Cells apoptosis and cells cycles were detected by-FACS. The bioinformatics tools were used to predict the target genes of miR-34a.Results1.The expression of miR-34a in breast cancer tissues was lower than that of normal tissues (P＜0.01); miR-34a was low expressed in MDA-MB-231and MCF-7compared to MCF-10A(P＜0.01), and lower in MDA-MB-231than MCF-7(P＜0.01). 2.Compared with the miR-NC(negative control) group, the miR-34a mimic cell group proliferation decreased both in MDA-MB-231and MCF-7(P<0.05).3.The migration cell numbers of the two cell lines were (286±42) vs(1037±83) and (87±8) vs (266±12), and invasion cell numbers were (173±23) vs (647±31)(P＜0.01),(38±6) vs (131±11)(P＜0.01).4.Apoptosis rates of MDA-MB-231and MCF-7both increased after transfected by miR-34amimic:(35.90±1.774)%vs(15.80±0.9103)%(P＜0.01)and(44.80±1.54)%vs(16.20±1.13)%(P＜0.01).Cells cycles were blocked at G0/G1both in MDA-MB-231and MCF-7:(68.56±2.2087)%vs (53.62±2.5875)%(P＜0.01) and (69.2±1.567)%vs (51.62±1.575)%(P＜0.01)5.The possible target genes of miR-34a were NOTCH1, SIRT1, MET, CDK6, E2F3and E2F5predicted by TargetScan, PicTar and miRanda.Conclusion1.The expression of miR-34a both in breast cancer tissues and cell lines were significant lower than normal tissues and MCF-10A.2.The up regulation of miR-34a can inhibit the proliferation, invasion, migration of MDA-MB-231and MCF-7, increase rate of cells apoptosis, and arrest cells cycle in the Go/G1, miR-34a act as a tumor suppressor in breast cancer cell.3.MiR-34a may through downregulating target genes (NOTCH1, MET, SIRT1, CDK6, E2F3, E2F5) to suppress the occurrence and progression of breast cancer.