Investigation Of Shc3 Activate MEK/ERK To Promote Proliferation And Metastasis In HCC

Objectives:Invasion and intrahepatic metastasis are the major reasons for the poor prognosis of hepatocellular carcinoma(HCC)patients.Methods:A microarray assay was performed on cell lines Huh7,MHCC97L,and HCCLM3 with increasing metastatic potential.Realtime qRT-PCR and Western blots further confirmed.We examined the functional significance of Shc3 expression in HCC.Immunoprecipitation and mass spectrometry were performed to identify proteins that interact with Shc3.To determine the tumorigenic relevance of Shc3 in vivo,we first examined the effects of Shc3 in intrahepatic tumor implantation mouse modelResults:To identify genes involved in HCC invasion and metastasis,we found increased Src homolog and collagen homolog 3(Shc3)expression in malignant HCC cell lines.Moreover,we found that Shc3 was significantly upregulated in tumors of 33 HCC patient samples as compared to the adjacent normal tissues.Further immunohistochemical analysis of 52 HCC patient samples showed that Shc3 expression correlates with microvascular invasion,cancer staging,and poor prognosis.Proteomic analysis showed that Shc3 interacts with major vault protein(MVP).Our mechanistic studies further showed that,the Shc3 and MVP interaction resulted in the activation of mitogen-activated extracellular signal-regulated kinase 1/2(MEK1/2)and extracellular signal-regulated kinase 1/2(ERK1/2)independent of Shcl and c-Raf.This interaction consequently induced the epithelial-mesenchymal transition(EMT)and promoted HCC cell proliferation and metastasis.Analysis of the Shc3 regulatory sequence revealed that the increase in Shc3 levels was due to demethylation of its upstream promoter,which allows c-Jun binding.In turn,Shc3 expression promotes c-Jun phosphorylation in a positive feedback loop.Analysis of metastasis using a tumor xenograft mouse model further confirmed the role of Shc3 in vivo.Conclusion:Taken together,our results indicate the importance of Shc3 in HCC progression and revealing a novel molecular mechanism by which Shc3 regulates downstream signaling through MVP independent of Shcl and c-Raf.Our results identify a novel therapeutic target and biomarker for HCC.