MicroRNAs Expression Profile In Human Breast Cancer BT474 Cells With Different Level Of HER2 And Effect Of Micro RNAs On Tumor Cell Biological Behavior

Objective: Detect the expression profile of micro RNAs(mi RNAs) in human breast cancer cells BT474 and BT474/ si RNA HER2, and screen out mi RNA expression profile related to HER-2. To provide the basis for the study of the mechanism of mi RNAs involved in HER2 signaling pathways regulating the biological behavior of breast cancer.Methods:1. Use RNA interference(RNAi) to silence the expression of HER2 gene in human breast cancer line BT474 by Lipofectamine. The expression profile of mi RNAs was detected by mi RNA microarray technique.2. The mi RNAs of significant differences in human breast cancer cells BT474 and BT474/ si RNA HER2 was detected by q RT-PCR. Hsa-mi R-1827 and hsa-mi R-3653 were used for further study.3. Transfect exogenous hsa-mi R-1827 mimics and hsa-mi R-3653 ASO to BT474 cells by Lipofectamine. Detect cell proliferation ability by MTT assay; transwell assay were used to detect cell invasion ability; investigate cell migration ability by application of wound-healing assay and transwell invasion assay4. The possible pathways which related to HER2 by application of bioinformatics methods were forecasted and analyzed by bioinformatics tools.Results:1. For fold change larger than 2.0, there are 338 mi RNAs related to HER2, including 110 up-regulated(hsa-mi R-345-3p, hsa-mi R-4292, hsa-mi R-4755-5p, hsa-mi R-1827, et al) and 228 down-regulated(hsa-mi R-208a-3p, hsa-mi R-3074-3p, hsa-mi R-4460, hsa-mi R-3653, et al) mi RNAs.2. The results of q RT-PCR showed that the expression of hsa-mi R-1827 was upregulated significantly in the BT474/ si RNA HER2 compared with BT474 cell lines,and hsa-mi R-3653 was down regulated significantly(P<0.05).3. Reduced cell migration was observed in hsa-mi R-1827 mimics and hsa-mi R-3653 ASO transfectant after the scratch in BT474 cells.4. Cell proliferation of BT474 cells transfected with hsa-mi R-1827 mimics and hsa-mi R-3653 ASO was significantly down compared to NC transfections(P<0.01).5. The cell number out of chambers of BT474 cells transfected with hsa-mi R-1827 mimics and hsa-mi R-3653 ASO was significantly reduced compared with the NC transfections.(P<0.01)。6. Hsa-mi R-1827 and hsa-mi R-3653 may involve in the occurrence and development of tumor through HER2 related pathways.Conclusion:1. mi RNA microarrays can detect the differentially expressed mi RNAs under different level of HER2 in human breast cancer BT474 cells.2. The expression of hsa-mi R-1827 was upregulated significantly in the BT474/ si RNA HER2 compared with BT474 cell lines,and hsa-mi R-3653 was down regulated significantly(P<0.05).3. Hsa-mi R-1827 may inhibit the invasion, proliferation and metastasis ability of breast cancer cells, and hsa-mi R-3653 may act in the opposite direction.