HMMR通过MEK/ERK信号通路促进肝细胞癌侵袭转移

HMMR promotes invasion and metastasis of hepatocellular carcinoma via activating MEK/ERK signaling pathway

目的探讨透明质酸介导的细胞游走受体(hyaluronan-mediated motility receptor,HMMR)对肝细胞癌侵袭转移的影响及潜在机制。方法采用qRT-PCR和Western blot法检测肝癌细胞系和肝癌组织,以及免疫组化检测肝癌组织中HMMR的表达;通过划痕实验、Transwell小室观察沉默/过表达HMMR对肝癌细胞迁移和侵袭能力的影响;通过小鼠肝癌肺转移模型观察沉默HMMR对肝癌肺转移的影响;采用Western blot检测HMMR对E-cadherin、N-cadherin、Vimentin、p-MEK、p-ERK等蛋白水平的影响。结果肝癌细胞系中HMMR呈高表达。肝癌组织中HMMR的表达水平显著高于癌旁组织(P<0.05),并且转移组癌组织中HMMR的水平明显高于非转移组(P<0.05)。沉默HMMR后细胞的迁移侵袭能力明显低于对照组(P<0.01),并且E-cadherin表达上调,N-cadherin、Vimentin表达下调(P<0.01);而过表达HMMR后细胞迁移侵袭能力显著增强(P<0.01),并且N-cadherin、Vimentin表达上调,E-cadherin表达下调(P<0.01)。体内实验结果显示基因敲减HMMR的肝癌细胞导致的肺转移病灶数显著低于对照组(P<0.05);过表达HMMR后p-MEK和p-ERK表达上调(P<0.01),而MEK、EKR无明显变化(P>0.05)。MEK抑制剂削弱了过表达HMMR介导的细胞的迁移侵袭(P<0.01)。结论HMMR在肝癌中高表达并且可能通过调控MEK/ERK信号通路从而促进肝细胞癌侵袭转移。

Objective To investigate the effect of hyaluronan-mediated motility receptor(HMMR)on the invasion and metastasis of hepatocellular carcinoma(HCC)cells.Methods The expression levels of HMMR in HCC cell lines and tissues were detected by qRT-PCR,Western blotting and immunohistochemical assay.The effects of silencing/overexpression of HMMR on the migration and invasion of HCC cells were observed by wound healing test and Transwell assay.Control HMMR cells and shRNA targeting HMMR cells were respectively injected into nude mice via tail vein to construct a mouse model of lung metastasis.Western blotting was used to detect the effect of HMMR expression on the protein levels of E-cadherin,N-cadherin,Vimentin,p-MEK and p-ERK.Results HMMR was highly expressed in liver cancer cell lines,and was generally up-regulated in HCC tissues than adjacent normal tissues(P<0.05),and the mRNA and protein levels of HMMR were significantly higher in the metastatic HCC tissues than the non-metastatic HCC tissues(P<0.05).Silencing HMMR weakened the migration and invasion abilities of cells(P<0.01),down-regulated E-cadherin protein level and up-regulated N-cadherin and Vimentin levels(P<0.01).While overexpression of HMMR promoted the motility and migration and invasion abilities of HCC cells(P<0.01),enhanced the expression of N-cadherin and Vimentin,and down-regulated the level of E-cadherin(P<0.01).In vivo study showed that knockdown of HMMR resulted in significantly less lung metastases than the control group(P<0.05),while,overexpression of HMMR enhanced the levels of p-MEK and p-ERK(P<0.01),but had no effect on MEK and ERK levels(P>0.05).Furthermore,MEK inhibitor U1026 significantly reduced the migration and invasion abilities of HMMR-overexpressed Huh7 cells(P<0.01).Conclusion HMMR is highly expressed in HCC cells,and may promote the migration and invasion of HCC cells via MEK/ERK signaling pathway.