title: [The siRNA-mediated silencing of Bmi-1 promotes apoptosis and inhibits invasion of MCF-7 breast cancer cells].
abstract: Objective To investigate the effect of small interfering RNA (siRNA)-mediated silencing of the Bmi-1 gene on cell proliferation and invasion of MCF-7 human mammary carcinoma cell line and the potential molecular mechanisms. Methods Real-time quantitative PCR was used to detect the levels of Bmi-1 mRNA in the paired breast cancer and adjacent noncancerous breast tissues which were confirmed by pathological diagnosis. Bmi-1-siRNA was transfected into MCF-7 cells by a Lipofectamine(R) RNAiMAX transfection reagent. Flow cytometry was used to detect cell cycle and apoptosis of MCF-7 cells transfected by Bmi-1-siRNA. Western blotting was performed to detect the protein levels of P21, Bax and Bcl-2. Matrigel Transwell(TM) invasion assay was used to determine the cell invasion of MCF-7 cells with Bmi-1 silencing. The protein levels of E-cadherin, N-cadherin, vimentin were tested by Western blotting. Results The expression of Bmi-1 mRNA in the breast cancer tissues was higher than that in the adjacent noncancerous breast tissues. Bmi-1 silencing significantly suppressed the cell growth, arrested the cells in the G1/S phase and promoted the apoptosis of MCF-7 cells. Compared with blank control group or negative control group, the Bmi-1-silenced group showed the increased expressions of P21 and Bax and the decreased expression of Bcl-2. In addition, Bmi-1 silencing significantly suppressed the cell invasion and promoted the expression of E-cadherin as well as downregulated the expressions of N-cadherin and vimentin in MCF-7 cells. Conclusion The invasion of MCF-7 cells can be inhibited by Bmi-1 silencing, of which the molecular regulation mechanism might be associated with the inhibition of tumor cell epithelial-mesenchymal transition.
authors.affiliation: Department of Biochemistry and Molecular Biology, Chongqing Research Center for Molecular Medicine and Tumor, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Xiaoyuan
authors.initials: X
authors.lastname: Deng
authors.affiliation: Department of Physiology, Chongqing Research Center for Molecular Medicine and Tumor, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Xiangmei
authors.initials: X
authors.lastname: Wu
authors.affiliation: Department of Biochemistry and Molecular Biology, Chongqing Research Center for Molecular Medicine and Tumor, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Huali
authors.initials: H
authors.lastname: Weng
authors.affiliation: Department of Biochemistry and Molecular Biology, Chongqing Research Center for Molecular Medicine and Tumor, Chongqing Medical University, Chongqing 400016, China. *Corresponding author, E-mail: fzsongcq@163.com.
authors.forename: Fangzhou
authors.initials: F
authors.lastname: Song
mesh_terms: D017209:Apoptosis / Q000235:genetics*; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D015820:Cadherins / Q000378:metabolism; D002465:Cell Movement / Q000235:genetics*; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D005434:Flow Cytometry; D059585:G1 Phase Cell Cycle Checkpoints / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D061986:MCF-7 Cells; D009361:Neoplasm Invasiveness; D063150:Polycomb Repressive Complex 1 / Q000235:genetics* / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014746:Vimentin / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: C494826:BAX protein, human; C069077:BMI1 protein, human; C493956:CDKN1A protein, human; D015820:Cadherins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D019253:Proto-Oncogene Proteins c-bcl-2; D014746:Vimentin; D051028:bcl-2-Associated X Protein; D063150:Polycomb Repressive Complex 1