Metalloproteinase meprin α regulates migration and invasion of human hepatocarcinoma cells and is a mediator of the oncoprotein Reptin.

Osman Breig,Gabrielle Couchy,Véronique Neaud,Johannes Prox,Christoph Becker-Pauly,Aude Grigoletto,Maïlyn Yates,Carlo Lucchesi,Jessica Zucman-Rossi,Jean Rosenbaum

doi:10.18632/oncotarget.13975

Abstract

Hepatocellular carcinoma is associated with a high rate of intra-hepatic invasion that carries a poor prognosis. Meprin alpha (Mep1A) is a secreted metalloproteinase with many substrates relevant to cancer invasion. We found that Mep1A was a target of Reptin, a protein that is oncogenic in HCC. We studied Mep1A regulation by Reptin, its role in HCC, and whether it mediates Reptin oncogenic effects.MepA and Reptin expression was measured in human HCC by qRT-PCR and in cultured cells by PCR, western blot and enzymatic activity measurements. Cell growth was assessed by counting and MTS assay. Cell migration was measured in Boyden chambers and wound healing assays, and cell invasion in Boyden chambers.Silencing Reptin decreased Mep1A expression and activity, without affecting meprin β. Mep1A, but not meprin β, was overexpressed in a series of 242 human HCC (2.04 fold, p < 0.0001), and a high expression correlated with a poor prognosis. Mep1A and Reptin expressions were positively correlated (r = 0.39, p < 0.0001). Silencing Mep1A had little effect on cell proliferation, but decreased cell migration and invasion of HuH7 and Hep3B cells. Conversely, overexpression of Mep1A or addition of recombinant Mep1A increased migration and invasion. Finally, overexpression of Mep1A restored a normal cell migration in cells where Reptin was depleted.Mep1A is overexpressed in most HCC and induces HCC cell migration and invasion. Mep1A expression is regulated by Reptin, and Mep1A mediates Reptin-induced migration. Overall, we suggest that Mep1A may be a useful target in HCC.

Highlights

Hepatocellular carcinoma (HCC) remains one of the deadliest cancers worldwide
We found that Reptin strongly regulated the expression of the secreted metalloprotease meprin α
We found that meprin α was consistently overexpressed in a large series of human HCC

Summary

Introduction

Hepatocellular carcinoma (HCC) remains one of the deadliest cancers worldwide. The prognosis of HCC is dictated both by the status of the host liver, very often cirrhotic, and by the tumor extension. Its homolog and partner protein, Pontin/RUVBL1 ( found overexpressed in HCC [3]) are part of several protein www.impactjournals.com/oncotarget complexes that have pleiotropic functions (for review, see [4]) They are involved in the remodeling of chromatin, the regulation of gene transcription through various mechanisms, and they act as chaperones for proteins of the Phosphatidylinositol Kinase-like Kinases family such as mTOR, ATM or DNA-PKcs. Briefly, they are involved in the remodeling of chromatin, the regulation of gene transcription through various mechanisms, and they act as chaperones for proteins of the Phosphatidylinositol Kinase-like Kinases family such as mTOR, ATM or DNA-PKcs We found that both proteins were required for the growth and viability of HCC cells [2, 3, 5] and that silencing Reptin within established HCC xenografts induced tumor regression, establishing Reptin as a potential target in HCC [6]. The downstream mediators of Reptin underlying its oncogenic effects remain to be found

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