The Expression Of MiR-191 In Breast Cancer And Its Effect On Proliferation And Invasion Of Human Breast Cancer Cell

Backgroud : Micro RNAs are a class of small endogenous non-coding RNA, it can bind to the base of its target gene m RNA completly or partially, which play an essential role in the process of post-transcriptional regulation by degradating the m RNA or hindering the translation of its target gene m RNA. micro RNA-191 involve in the biological process of large number of tumors, but few report about the exact functional mechanism of mi R-191 in the development of breast cancer has been reported.Estrogen receptor status is that estrogen and progesterone’s receptor express in breast cancer, which is associated with the biological behavior of breast cancer.It has been reported that PLCD1 is an tumor suppressor gene which can suppress the proliferation and invasion of cancer cell, down-regulation of expression of PLCD1 can promote the development of cancer cell.Many papers have been reported that PLCD1 is one of the target genes in mi RNA, so it is associated with the expression of mi RNA. To test the expression of mi R-191 in breast cancer cells and its effect on proliferation and invasion of breast cancer cells, the breast cancer cell line which contained different hormonereceptor status and the normal breast epithelial cell line was selected in this study, and explored the expression of mi R-191 in breast cancer and normal breast epithelial cell by real-time PCR and its role on the biological behavior of breast cancer cell by Cck-8,flow cytometry assay and transwell assay. After that,PLCD1,the target gene of mi R-191, was tested by real-time PCR and western blot.Objective: to test the expression of mi R-191 in breast cancer cells and its effect on proliferation and invasion of MCF-7cells, explore the relationship between mi R-191 and PLCD1, analyse its possible mechanism in order to provide a potential target of diagnosis and treatment in breast cancer preliminary.Methods1)The relative expression of mi R-191 in normal breast epithelial cell(HBL-100) and breast cancer cell(MCF-7, MDA-MB-231) was tested by real-time PCR.2)The mi R-191 inhibitor was transfected into MCF-7 cell lines by lipofectamine2000 and the transfection efficiency was detected by real-time PCR.3)The ability of cell proliferation was tested by Cck-8 assay. The cell cycle was detected by FACS(flow cytometry assay). The ability of cell invasion was detected by transwell assay.4)Real-time PCR and western blot was used to detect the expression of PLCD1 m RNA and protein level respectively.Results1) We notice that the expression of mi R-191 in cancer cell lines(MCF-7 、 MDA-MB-231) was significantly higher than that in normal breast epithelial cell line, HBL-100(P<0.01). Besides, the level of mi R-191 in ER positive cell lines(MCF7) was higher than that in ER negative cell lines(MBA-MD-231(P<0.01);2)Compared to control group, the expression of mi R-191 in MCF-7was significantly downregulation after mi R-191 inhibitor being successfully transfected into MCF-7;3) After transfected with mi R-191 inhibitor, the proliferation ability of MCF-7 cells was suppressed significantly(P<0.01), the percentages of cells in G0/G1 phase increased(P<0.01) and the invasion ability of MCF-7 cells were significantly inhibited(P<0.01).4) We notice that the expression of gene PLCD1 m RNA and protein was negatively correlative with the expression of mi R-191.Conclusion:Our study show that mi R-191 is over-expressed in breast cancer cells,especially in ER positive breast cancer cell lines(MCF-7).Proliferation and invasion of MCF-7 cells were significantlysuppressed by mi R-191 inhibitor, which suggested that mi R-191 may promote the proliferation and invasion of breast cancer cell and the probable mechanism was the negatively regulation of PLCD1 m RNA by mi R-191. This study help us to understand the possible molecular mechanism in the development of breast cancer, it also provided a potential target of the diagnosis and treatment of breast cancer.