Microenvironment and cancer : role of adamalysins in tumor progression

Le micro-environnement tumoral joue un rôle dans la croissance, l'invasion tumorale et la résistance aux traitements. Il est essentiel de comprendre les mécanismes qui régulent la communication entre les cellules tumorales et ce micro-environnement pour développer des thérapies efficaces. Dans ce contexte, les protéases extracellulaires de la famille des Adamalysines sont des acteurs importants dans la progression tumorale en agissant sur le remodelage de la matrice extracellulaire (MEC) et la biodisponibilité des médiateurs de communication cellulaire tels que les cytokines, les chimiokines et les facteurs de croissance. Mes travaux ont mis en évidence une nouvelle interaction entre ADAM12, un marqueur mésenchymateux induit au cours de la transition épithélio-mésenchymateuse (EMT) dépendante du TGF-β et ZO-1, une protéine d’échafaudage exprimée dans des jonctions serrées de cellules épithéliales. Ces deux protéines sont redistribuées, dans des structures de type invadopodes pour promouvoir la dégradation de la MEC. Nous avons par ailleurs réalisé un criblage in silico qui nous a permis d’identifier un cluster d’adamalysines dont les gènes sont co-exprimés chez des patients atteints d’un carcinome hépatocellulaire. Parmi ces adamalysines, nous avons mis en évidence la protéine ADAMTS12, qui joue un rôle clé dans le développement de la fibrose hépatique en lien avec une réponse inflammatoire aigüe ou chronique.Tumor microenvironment plays a major role in tumor growth, invasion and resistance to treatments. Understanding the mechanisms that regulate communication between tumor cells and their microenvironment is essential to develop effective therapies. In this context, Adamalysin extracellular proteases play major role in tumor progression, by modulating the extracellular matrix (ECM) remodeling and the bioavailability of cell communication mediators such as cytokines, chemokines and growth factors. My work revealed a new interaction between ADAM12, a mesenchymal marker induced during the epithelial-mesenchymal transition (EMT) dependent on TGF-β and ZO-1, a scaffolding protein expressed in tight junctions of epithelial cells. Both proteins are redistributed in invadopodia-like structures to promote ECM degradation. In a second study, we carried out an in silico screening that allowed us to identify a cluster of Adamalysin genes co-expressed in patients with hepatocellular carcinoma. Among these Adamalysins we have studied the protein ADAMTS12 in more details, and shown that this protein plays a key role in the development of liver fibrosis involving an acute or chronic inflammatory response

Proteomic screening identifies the zonula occludens protein ZO-1 as a new partner for ADAM12 in invadopodia-like structures

International audienceThe epithelial mesenchymal transition (EMT) is a key process for cancer cell invasion and migration. This complex program whereby epithelial tumor cells loose polarity and acquire mesenchymal phenotype is driven by the regulation of cell-cell adhesion and cell-substrate interactions. We recently described the association of ADAM12 with EMT and we now use immunoprecipitation and proteomic approaches to identify interacting partners for ADAM12 during EMT. We identify twenty proteins that are involved in molecular mechanisms associated with adhesion/invasion processes. Integrative network analyses point out the zonula occludens protein ZO-1, as a new potential partner for ADAM12. In silico screening demonstrates that ZO-1 and ADAM12 are coexpressed in breast cancer cell lines sharing EMT signature. We validate the interaction between ZO-1 and ADAM12 in invasive breast cancer cell lines and show that ZO-1 and ADAM12 co-localize in actin-and cortactin-rich structures. Silencing either ADAM12 or ZO-1 inhibits gelatin degradation demonstrating that both proteins are required for matrix degradation. We further show that matrix metalloprotease 14, known to mediate degradation of collagen in invadopodia-like structures interacts with ZO-1. Depletion of PKCε that regulates the recruitment of ADAM12 and ZO-1 to cell membranes induces a decrease in ADAM12 and ZO-1 at invadopodia-like structures and degradation activity. Together our data provide evidence for a new interaction between ADAM12, a mesenchymal marker induced during TGF-β-dependent EMT and ZO-1, a scaffolding protein expressed in tight junctions of epithelial cells, both proteins being redistributed at the invadopodia-like structures of mesenchymal invasive cells to promote PKCε-dependent matrix degradation

Integration of miRNA‐regulatory networks in hepatic stellate cells identifies TIMP3 as a key factor in chronic liver disease

BACKGROUND & AIMS: Activation of hepatic stellate cells (HSC) is a critical process involved in liver fibrosis. Several miRNAs are implicated in gene regulation during this process but their exact and respective contribution is still incompletely understood. Here we propose an integrative approach of miRNA-regulatory networks to predict new targets. METHODS: miRNA regulatory networks in activated HSCs were built using lists of validated miRNAs and the CyTargetLinker tool. The resulting graphs were filtered according to public transcriptomic data and the reduced graphs were analysed through GO annotation. A miRNA network regulating the expression of TIMP3 was further studied in human liver samples, isolated hepatic cells and mouse model of liver fibrosis. RESULTS: Within the up-regulated miRNAs, we identified a subnetwork of five miRNAs (miR-21-5p, miR-222-3p, miR-221-3p miR-181b-5p and miR-17-5p) that target TIMP3. We demonstrated that TIMP3 expression is inversely associated with inflammatory activity and IL1-ß expression in vivo. We further showed that IL1-ß inhibits TIMP3 expression in HSC-derived LX-2 cells. Using data from The Cancer Genome Atlas (TCGA), we showed that, in hepatocellular carcinoma (HCC), TIMP3 expression is associated with survival (P < .001), while miR-221 (P < .05), miR-222 (P < .01) and miR-181b (P < .01) are markers for a poor prognosis. CONCLUSIONS: Several miRNAs targeting TIMP3 are up-regulated in activated HSCs and down-regulation of TIMP3 expression is associated with inflammatory activity in liver fibrosis and poor prognosis in HCC. The regulatory network including specific miRNAs and TIMP3 is therefore central for the evolution of chronic liver disease

ADAMTS12 is a stromal modulator in chronic liver disease

International audienceAdamalysins, a family of metalloproteinases containing disintegrin and (ADAMs) ADAM with thrombospondin motifs (ADAMTSs), belong to the matrisome play important roles in various biological pathological processes, such as development, immunity cancer. Using liver cancer dataset from International Cancer Genome Consortium, we developed an extensive silico screening that identified cluster adamalysins co-expressed livers patients hepatocellular carcinoma (HCC). Within this cluster, ADAMTS12 expression was highly associated recurrence risk poorly differentiated HCC signatures. We showed expressed stromal cells tumor adjacent fibrotic tissues patients, more specifically activated stellate cells. mouse model carbon tetrachloride-induced injury, Adamts12 strongly transiently after 24 h acute treatment, fibrosis exacerbated Adamts12-null mice submitted chronic injury. HSC-derived LX-2 cell line, silencing resulted profound changes gene program. In particular, genes previously reported be induced upon HSC activation, PAI-1, were mostly down-regulated following knock-down. The phenotype these changed less state, showing altered actin network decreased nuclear spreading. These phenotypic changes, together down-regulation offset by TGF-β treatment. present study thus identifies modulator differentiation, new player disease