ELF3 Promotes HCC Epithelial-mesenchymal Transition(EMT) Through MiRNA-141-3p Targeting ZEB1

BackgroundHepatocellular carcinoma(HCC)is one of the most common malignancies and the third leading cause of cancer death in human.Although the advanced in the treatments for HCC,the prognosis of is still unfavorable because of the high rate of tumor recurrece and metasis.Epithelial mesenchymal transition(EMT)plays a major role in HCC progression.Several intriguing studies have demonstrated that epithelial-mesenchymal transition(EMT)plays an important role in cancer metastasis.Recent studies have shown that ELF3 is involved in cancer cell proliferation,differentiation and migration in many human tumors.However,the role of ELF3 in HCC is unknown.MicroRNAs(miRNAs)are small,non-coding RNAs of 20-24 nucleotides that post-transcriptionally modulate gene expression by directly interacting with the 3’ or 5’untranslated region of target mRNAs.Recent studies have suggested that miRNAs play important roles in tumor development,invasion and metastasis.ZEB1(zinc finger E-box binding homeobox 1)is one of the most important promoter of EMT.Recently studies showed that ZEB1 inhibits repression of the E-cadherin in many tumors.ObjectiveELF3 is one of the number of the E26 transformation-specific(ETS)family of transcription factors.Recently studies showed that ELF3 was involved in cancer proliferatin,differentiation and migration in many human tumors.However the role of ELF3 in HCC is still unclear.Therefore,In the present study,we studied the expression of E74 like ETS Transcription Factor 3(ELF3)in HCC,and explored its functions in HCC.MethodThe expression of ELF3 in HCC was tested by Western blotting,qPCR,and Immunohistochemistry.Kaplan-Meier analysis and log-rank test were performed to estimate the association of ELF3 expression with prognosis of HCC patients.We investigated the role of ELF3 in cell proliferatin by CCK-8 and colony formation.Migration and invasion assay were performed to evaluate the effect of ELF3 on cell mobility.We used Western blotting and qPCR to examine the expression of EMT associated marker in Huh7 cells when ELF3 was overexpressed,or in MHCC-LM3 when ELF3 was depleted.And we screened a group of miRNAs which targeted ZEB1 directly.We used Chromatin Immunoprecipitation(CHIP)and Luciferase assay to clarify how ELF3 regulated miR-141-3p.At last,spleen injection-liver metastasis assay in nude mice was performed to investigated the role of ELF3 in metastasis and invasion in vivo.ResultsWe found that ELF3 was increased in HCC tissues and its overexpression was associated with a poor prognosis for HCC patients.The upregulated expression of ELF3 was tested by immunohischemistry in 106 HCC clinical samples and the results showed that ELF3 expression was significantly correlated with tumor size(p=0.048).The results of univariate and multivariate analysis indicated that ELF3 over-expression was significantly correlated with OS and DFS of HCC patients.Gain-and-loss function studies revealed that increased expression of ELF3 promoted HCC cell proliferation,migration,invasion and EMT.Opposite results were observed when ELF3 was silenced.Chromatin immunoprecipitation assay revealed that ELF3 could bind to the promoter of miR-141-3p and suppress miR-141-3p.Spleen injection-liver metastasis assay showed that ELF3 promote metastasis and invasion in vivo.ConclusionIn conclusion,our findings first revealed that ELF3 was upregulated in HCC tissues.Moreover,in vivo and in vitro assays showed that ELF3 promoted EMT by activating ZEB1;silencing ELF3 downregulated ZEB1 and upregulated E-cadherin by relieving the inhibition of miR-141-3p expression.Our discoveries highlight ELF3 as a promising biomarker and therapeutic target for HCC.