HuR Promotes The Proliferation,Migration And Invasion Of Hepatocellular Carcinoma Cells By Regulating The STRA6 Signaling Pathway

Objective:Previous studies have shown that HuR gene is highly expressed in liver cancer tissues,but the molecular mechanism of HuR in hepatocellular carcinoma is still unclear.This research aimed to explore the effects and related mechanisms of HuR and related downstream targets on the proliferation,migration,invasion and colony formation abilities of hepatocellular carcinoma cell lines Hep G2 and SMMC-7721.Methods:The expression difference of HuR was detected by the cancer genome atlas(TCGA)and gene expression omnibus(GEO)in liver cancer tissues and normal liver tissues.SMMC-7721 cell line of HuR overexpression or knockdown was constructed and verified by Western bolt.The cell proliferation,invasion,migration and colony formation abilities were determined in vitro by real time cell analysis(RTCA),the wound healing assays and colony formation assays,respectively.Immunofluorescence,immunohistochemistry and co-immunoprecipitation were used to detect the expression and interaction of HuR and its downstream related proteins.The expression of stimulated by retinoic acid 6(STRA6),the downstream target of HuR,was inhibited by RNA interference technology.The expression of JAK2 was inhibited by AT9283(an inhibitor of JAK2),and the expression of STAT3 was inhibited by NSC74859(an inhibitor of STAT3).Next,we observed changes in cytological phenomena and explored its mechanism.Furthermore,the expression of HuR and related proteins were detected in vivo through liver cancer modeling and the tumorigenesis experiment in nude mice.Results:The results of bioinformatics and liver cancer modeling showed that HuR was highly expressed in liver cancer tissues.Hepatocellular carcinoma cell line SMMC-7721 of HuR overexpression or knockdown was successfully constructed.Compared with the empty vector group(Vector),the proliferation,migration,invasion and colony formation abilities of the HuR overexpression group(HuR-OE)increased 1.6 times,1.4times,9 times and 1.6 times in SMMC-7721 cells,respectively.Moreover,compared with the negative control group(sh NC),the proliferation,migration,invasion and colony formation abilities of the HuR knockdown group(sh HuR)were reduced by57%,88%,74% and 90% in SMMC-7721 cells,respectively.The results of Western bolt showed that the expression of STRA6,JAK2 and STAT3 were increased with the overexpression of HuR,and the expression showed a certain correlation.The results of co-precipitation and protein co-localization indicated that STRA6,JAK2 and STAT3 can interact with each other.The knockdown of STRA6 can inhibit the proliferation,migration and invasion of Hep G2 and SMMC-7721 cells.In addition,the inhibition of STRA6,JAK2 or STAT3 in SMMC-7721 cells partially reversed the cancer-promoting behavior caused by the overexpression of HuR,respectively.Conclusion:HuR promotes the proliferation,migration and invasion of hepatocellular carcinoma cells by regulating STRA6 signaling pathway.