RNF4 Promates The Proliferation Of Cholangiocarcinoma Cells Via The Degradation Of P27kip1 In Nuclear

Objective: To investigate the expression of RNF4 and p27kip1 in cholangiocarcinoma,and its relationship with the clinical pathological characteristics respectively.Moreover,to explore the correlation between RNF4 and p27kip1,especially the effect of RNF4 on the proliferation of cholangiocarcinoma cells via p27kip1 degradation in nuclear.Methods: The tumor and adjacent tissues were obtained from 35 patients with cholangiocarcinoma who underwent surgical resection from February 2016 to February 2018.The expression of RNF4 and p27kip1 was detected by immunohistochemical staining in tumor and adjacent tissues.Chi-square test and rank sum test were used to analyze the relationship between the expression of RNF4 or p27kip1 and clinical features.The cholangiocarcinoma cell line TFK1 was transfected with over-expressing RNF4 lentivirus,and the groups of RNF4 over-expression(TFK1 RNF4)were set up,as well as the groups of negative control(Control).Western blot was used to detect the expression of RNF4 and p27kip1 in two groups.CCK-8 assay and cell clone formation assay were used to study the effect of RNF4 on the proliferation of cholangiocarcinoma cells.Results: Compared to adjacent tissues(3.686±2.988),RNF4 was expressed higher(P<0.01)in tumor tissues(7.371±3.507).And the expression of RNF4 was significantly related to TNM stage(P<0.05)and differentiation(P<0.01).On the contrary,the expression of p27kip1 was lower(P<0.05)in tumor tissues(4.086±3.052)than adjacent tissues(6.000±3.272),and was significantly related to TNM stage(P<0.01)and differentiation(P<0.05).Meanwhile,the expression of RNF4 and p27kip1 was negatively correlated(r=-0.499,P<0.01)in tumor tissues,but not in adjacent tissues(r=0.075,P=0.67).In the groups of RNF4 over-expression(TFK1 RNF4),p27kip1 was down-regulated and mainly localized in nuclear,while SUMO2/3 and UBC9 were up-regulated.In addition,the OD value and the number of cell clones were significantly increased.Conclusion: The higher expression of RNF4 may play an important role in the development of cholangiocarcinoma by degrading p27kip1 in nuclear and weakening the inhibition of p27kip1 on cell cycle.