The Mechanism Of CSN5-mediated Hepatocellular Carcinoma Proliferation Through MAT2A

Objective:To study the role of deubiquitinase constitutive photomorphogenic-9signalosome subunit 5(CSN5)in HCC growth,and explore the underlying mechanism.Methods:Immunohistochemical staining,quantitative Real-time PCR and Western blot were employed to investigate the expression of CSN5 in HCC and corresponding normal tissues,and the difference of CSN5 expression between HCC tissues and adjacent tissues was further investigated.The expression of CSN5 m RNA and protein in HL-7702,Hep G2,MHCC97 H,HCCLM3 and Huh7 cells were detected by quantitative Real-time PCR and Western blot.Furthermore,the sh CSN5 RNA sequences were transfected into HCCLM3 cells.The expression of CSN5 was detected by Real-time PCR and Western blot,and the proliferation ability of HCC cells was detected by Ed U assay.In addition,Western blot was used to detect the m RNA and protein expression of Methionine adenosyltransferase 2A(MAT2A)in HCCLM3 cells transfected with sh CSN5 RNA.Results:(1)The expression level of CSN5 in HCC tissues was significantly higher than that in corresponding normal tissues(P<0.01).In HCC cell lines,CSN5 expression was also markedly higher than that in normal hepatocyte(P<0.05).(2)After shCSN5 RNA transfection,the levels of CSN5 m RNA and protein in HCC HCCLM3 cells were significantly decreased(P<0.001),and the proliferation ability of HCC cells was markedly inhibited(P<0.01).(3)In CSN5 knockdown HCCLM3 cells,the total protein level of MAT2A was significantly decreased(P<0.01).CSN5 suppression can reverse the upregulated MAT2A expression and the enhanced HCC cells growth promoted by MAT2A overexpression.(4)mRNA and protein levels of CSN5 in 31 HCC samples were positively correlated with MAT2A(P<0.01).Conclusion:(1)The expression levels of CSN5 in HCC tissues were aberrantly upregulated.(2)CSN5 knockdown in HCC cells inhibited HCC cells growth.(3)CSN5 can regulate the proliferation of HCC cells through MAT2A.