Overexpression Of DJ-1 Enhances Colorectal Cancer Cells Proliferation Through The Cyclin-D1/MDM2-p53 Signaling Pathway

Objective:To explore the expression and biological function of DJ-1 in colorectal cancer.To analyze the effect of DJ-1 regulating p53 on the proliferation of colorectal cancer cells;To analyze the molecular mechanism of DJ-1 regulating p53 protein expression;and finally to elucidate the molecular mechanism of DJ-1 on p53 expression and its effect on the proliferation of colorectal cancer cells.Methods:1.The expression of DJ-1 protein in colorectal cancer was detected by RT-qPCR and IHC,and the relationship between the expression of DJ-1 and clinicopathologic features was analyzed by univariate and multivariate regression analysis.Kaplan-Meier survival analysis of the overall survival and disease-free survival in two groups defined by low and high expression of DJ-1 in patients with CRC.2.To change the expression of DJ-1 in colorectal cancer cell lines,and to detect the ability of invasion and migration,proliferation activity and expression of proliferation-associated antigen;Meanwhile,flow cytometry was performed to analyze the changes of cell cycle and apoptosis.3.Change the expression of DJ-1 in colorectal cancer cell lines,and observe the changes of p53,Cyclin-D1 protein and mRNA.Change the expression of p53 while changing the expression of DJ-1,and detect the change of cell proliferation activity and the expression of proliferation-related antigens;Restore DJ-1 expression or induce DJ-1 expression in knockout DJ-1 cell lines,and detect changes in p53 protein expression;Co-immunoprecipitation(Co-IP)to detect the binding of endogenous DJ-1 and p53;Stably overexpress or interfere with DJ-1 in colorectal cancer cell lines,and detect changes in the expression of p53,Cyclin-D1 and downstream related proteins.Results:1.RT-qPCR and IHC showed that DJ-1 protein was highly expressed incolorectal carcinoma,and further analysis showed that high expression of DJ-1protein was significantly correlated with lymph node metastasis and TNM stage,patients with high DJ-1 protein expression had a shorter overall survival time;DJ-1was an independent risk factor for poor prognosis in patients with colorectal cancer.2.Cell function experiments showed that DJ-1 interference inhibited the proliferation,invasion and migration of colorectal cancer cells and the expression of Cyclin-D1 and PCNA;over-expression of DJ-1 showed the reverse effect;Western blot showed that the expression of Cyclin-D1 was decreased and p53 was increased by interfering with DJ-1.3.In CRC cell lines,DJ-1 was down-regulated and Cyclin-D1 protein and Mrna levels were also decreased.The protein and mRNA levels of p53 also increased DJ-1promotes the proliferation of colorectal cancer cells through Cyclin-D1/MDM2-p53 signaling pathway.Conclusion:(1)DJ-1 protein is highly expressed in colorectal cancer tissues and interferes with DJ-1 to inhibit the proliferation and invasion of colorectal cancer cells;(2)DJ-1promotes the proliferation of colorectal cancer cells through Cyclin-D1/MDM2-p53 signaling pathway;...