The Inhibition And Mechanism Of 6-TG On MCF-7 Breast Cancer Cells

Breast cancer is a common cancer affecting women's health,and its morbidity and mortality will increase significantly in the coming years.Among young women under 45 years of age,breast cancer is the main cause of cancer-related deaths,and breast cancer is highly heterogeneous,with potentially aggressive and complex biological characteristics.DNA methylation is abnormal during the development of human cancer.DNA methyltransferase 1(DNMT1)is the main catalytic enzyme that regulates DNA methylation.The abnormal expression of DNMT1 affects many biological pathways including gene expression and silencing,cell cycle control,growth factor or receptor signaling.DNMT1 is essential for the development of breast cancer,and it is highly expressed in breast cancer patients.Therefore,in this study,MCF-7 breast cancer cells were treated with 6-TG as a potential drug candidate to inhibit DNMT1 activity,and its effects on MCF-7 cell proliferation,apoptosis and cell cycle were explored at the cell level.The anti-tumor mechanism in MCF-7 breast cancer cells was studied by RNAseq and bioinformatics technology system.Finally,based on the inhibitory effect of 6-TG on MCF-7 breast cancer cells,the regulatory mechanism of ceRNA in MCF-7 cells was clarified,and corresponding potential biological targets were screened.The main experimental results are as follows:1.The effects of 6-TG on the biological characteristics of MCF-7 breast cancer cells:(1)The MCF-7 and MCF-10 A cells were treated with 6-TG at different concentrations.The results showed that MCF-7 cells were more sensitive to 6-TG compared to MCF-10 A cells and the IC50 was 5.481 ?M.(2)The results of clone formation assay and flow cytometry showed that 6-TG can significantly inhibit the proliferation and induce apoptosis of MCF-7 cells.(3)The result of cell cycle flow cytometry showed that 6-TG affected MCF-7 cell cycle progression and caused G2 / M phase arrest.2.The mechanism of 6-TG treated MCF-7 breast cancer cells:(1)Apoptosis,cell cycle and p53 signaling pathway were the main pathways for 6-TG to inhibit the growth of MCF-7 breast cancer cells.(2)6-TG inhibited the protein expression of DNMT1 in MCF-7 breast cancer cells,regulated and increased the protein expression of FAS and activated the apoptotic pathway,eventually caused the apoptosis of MCF-7 cells.(3)6-TG inhibited the protein expression of DNMT1 in MCF-7 breast cancer cells,and inhibited the expression of CDK1 and CDK2 through the indirect regulation of CDKM1 A,and finally caused the cell cycle arrest of MCF-7 cells.3.LncRNA-related ceRNA network construction and analysis in the MCF-7 breast cancer cells based on the treatment of 6-TG:(1)6-TG induced MCF-7 cell apoptosis and significantly affected lncRNA expression in MCF-7 breast cancer cells,of which 1463 and 158 differentially expressed lncRNAs were up-regulated and downregulated,respectively.(2)Based on the differential RNA analysis of MCF-7 breast cancer cells treated with 6-TG,a ceRNA network consisting of 4 lncRNAs,10 miRNAs,and 25 mRNAs was successfully constructed and verified dthe regulatory mechanism of lncRNA as a ceRNA molecule.(3)Based on the ceRNA network,MIR22 HG,LINC00324,hsa-miR-370 and hsa-miR-424 were screened as potential biological targets for breast cancer prognosis,providing a new theoretical basis for targeted therapy and prognostic evaluation of breast cancer.