Influence Of Hypoxia On The Expression Of MiRNA-21in Human Breast Cancer MCF-7Cells And Its Relationship With The Cell Proliferation And Apoptosis In Vitro

Obiective To investigate the effects of hypoxia microenvironment on the proliferationand apoptosis of human breast cancer MCF-7cells, preliminary explore the effects ofhypoxia on microRNA-21expression, cell proliferation and apoptosis.Methods1Human breast cancer MCF-7cells were divided into normoxic and hypoxiagroup, in oxicnorm group of MCF-7cells were cultured in complete medium withoutCoCl2(0μmol/L), in hypoxia group of MCF-7cells were induced by CoCl2concentrationsof100、200、400μmol/L.2MTT assay was used to monitor the situation of CoCl2-induced hypoxia on proliferation of human breast MCF-7cells in vitro.3The change ofcell apoptotic ratio were detected by flow cytometry.4Reverse transcription polymerasechain reaction (RT-PCR) was used to examine the expression of HIF-1α mRNA indifferent hypoxia level, and the expression of miRNA-21was assessed by stem-loop RT-PCR.Results1Compared with the cells without CoCl2treatment, The effect of growthinhibiton was more obvious in the increase of CoCl2concentration and exposure time.The cells treated with100and200μmol/LCoCl2still had proliferation ability in a certainperiod of time.2The apoptosis rate of CoCl2treatment group was higher than that of thecontrol group.3The HIF-1α mRNA expression levels of the all treated with CoCl2weresignificantly higher than that of control group (P<0.05), the miRNA-21mRNAexpression levels of groups treated with200and400μmol/L were significantly higherthan that of control group (P<0.05).Conclusion Human breast cancer MCF-7cells are grown in a certain degree of hypoxiaand time. Cell apoptosis rate increase by hypoxia induced. Hypoxia condition can up-regulate the expression of HIF-1α and miRNA-21, miRNA-21expression had a positivecorrelation with HIF-1α in this process.