Methylseleninic Acid Regulated The Apoptosis Of Mice Transplanted By Mouse Breast Cancer Cells Through JAK/STAT Signaling Pathway

Studies have shown that there are different ways of using MSA to prevent tumor.MSA can induce apoptosis of breast tumor,but its mechanism in breast tumor has not been fully understood.It has been confirmed that JAK/STAT signaling pathway related factors(JAK1,JAK2,JAK3,STAT1,STAT2,STAT3,STAT5 A,STAT5B,STAT6)and MMPs(MMP2,MMP9,TIMP1,TIMP2)participate in tumor growth,proliferation and metastasis through a variety of ways,associating with tumorigenesis and tumor development closely.In order to investigate the effect mechanism of JAK/STAT signaling pathway on growth inhibition of breast tumor with MSA treatment,we used the transplanted tumor model of BALB/C mice transplanted with 4T1 mouse breast cancer cells,the JAK2 inhibitor AG490 as the positive control,to analyze the different expression of JAK/STAT signaling pathway in the process of MSA-induced breast tumor apoptosis.60 female BALB/C mice were fed in Animal experiment center of Huazhong Agricultural University.The mice were randomly divided into six groups,including control group,MSA treatment group,CTX treatment group,tumor group,MSA treatment tumor group and CTX treatment tumor group(10 only/group).The tumor group,MSA treatment tumor group and CTX treatment tumor group were selected to construct the transplanted tumor model of mammary gland.The tumor suppression effect was calculated according to the quality and volume of separated tumors.The degree of apoptosis was detected by fluorescence TUNEL staining in breast tissues and breast transplanted tumors.At the 4T1 mouse breast cancer cell level.The experiment was divided into four groups,including control group,MSA deficiency(5 ?mol/L)treatment group,MSA-rich(20 ?mol/L)treatment group and AG490(40 ?mol/L)treatment group,agents treated for 48 hours before collecting cells.Flow cytometry was used to detect apoptotic rate in cell experiment,and RT-qPCR and western blot were used to detect the mRNA and protein expression of JAK/STAT signaling pathway,MMPs,and apoptosis factors.The weight and volume of transplanted tumors group were significantly decreased in MSA treatment tumor group after drug treatment.Fluorescence TUNEL staining of tissues showed that MSA treatment group of the normal groups were consistent with the control group in the degree of apoptosis.In the transplanted tumor groups,the apoptosis was increased significantly in MSA group compared with control group.In cell experiment,Flow cytometry detection showed that the apoptosis of MSA-rich treatment group and AG490 treatment group were increased successively comparing with control group.The results of gene expression in MSA-rich treatment group comparing with control group showed that the mRNA and protein expression of MMP2 and MMP9 were decreased successively,the mRNA and protein expression of TIMP1 and TIMP2 were increased successively,and the protein expression of pJAK2 and pSTAT3 were decreased successively,and the protein ratio of Bax and Bcl-2 was increased successively.In the animal model of breast transplanted tumor,MSA can induce the apoptosis of transplanted tumor,inhibiting the growth of tumor.In cell experiment,MSA can induce apoptosis of tumor cell,and share the same trend with AG490,JAK2 specific inhibitor,regulating the cytokine expression of JAK/STAT signaling pathway.Therefore,the possible mechanism of MSA inhibiting growth of breast transplanted tumor was that MSA influenced the activation of JAK2 and STAT3 from JAK/STAT signaling pathway,down-regulated the expression of downstream effect factor MMP2 and MMP9 and up-regulated the expression of their inhibitor TIMP2 and TIMP1.MSA treatment increased the Bax/Bcl-2 protein ratio,inducing apoptosis of transplanted tumor and exerting an anti-neoplastic effect.