Valérie Paradis & Alain Couvineau
From inflammation to cancer in digestive diseases
This project results of the merging of 3 research teams from the past 5-years contract and aims to investigate specific aspects of the physiopathology of the sequence inflammation-cancer in digestive tract, identify new diagnostic markers and develop innovative therapeutic targets. First axis, focusing on liver carcinogenesis related to metabolic syndrome, will identify the specific mechanisms involved in inflammatory liver damages by favoring original in situ molecular approaches such as mass spectrometry imaging (MSI). The contribution of lipid environment (liver or visceral adipose tissue) in the progression to hepatocellular carcinoma (HCC) will also be investigated. Second axis will provide new insights in the role of GPCR in the progression of digestive cancers, which will allow the development of new therapeutic strategies. We will focus on (1) orexins and their receptors (OXR) which induce a robust apoptosis in digestive cancers, and (2) CXCR4 which confers survival, invasion potential to cancer cells. We will be especially interested to evaluate potential effects of these targets in preclinical models of digestive cancers that have developed resistance to conventional cytotoxic or targeted therapies.
Work package: Inflammation, fibrosis and cancer in the liver
Metabolic syndrome (MS) is becoming the leading cause of chronic liver diseases worldwide and may result in the development of chronic liver diseases and hepatocellular carcinoma (HCC). Progression of liver carcinogenicity in MS is complex, involving the development of tissue damages (steatosis and fibrosis) and also an inflammatory systemic background through adipokines production from visceral adipose tissue
Our project aims:
- To study the molecular mechanisms involved in the development of early liver damage related to MS (steatosis and steatohepatitis) which start in centrolobular area. The liver lipidomic pattern will be determined by an in situ approach. This study will allow to identify profibrogenic mediators specifically induced in the liver damage progression observed in MS. The functional role of fibrogenesis will estimated by using cell co-culture models (liver stellar cells/hepatocytes/endothelial cells).
- To decipher the specific molecular mechanisms involved in tumor progression associated to MS by the determination of the role of visceral adipose tissue (VAT) through the production of Fatty Acid Binging Proteins (FABPs) and lipid chaperones which are involved in the fatty acid trafficking. The role of pro-oncogenic of FABP4 will determined using in vitro and in vivo experimental models. Moreover, we will examine the impact of tissue modifications in the peritumoral hepatic parenchyma on HCC development by using in situ proteomic and lipidomic approaches. In this context, we will evaluate the anti-tumoral effects of putative therapeutical targets including the metformine.
This project will be based on the development of innovative technologies including mass spectrometry imaging (MALDI imaging), tissue culture models (ex vivo models) and animal models which reproduced liver damages related to MS (High fat diet, fructose diet …). The determination of molecular species identified by MALDI was carried out in collaboration with JM Camadro’s group (Institut J. Monod, Paris).
Work package: GPCRs and digestive cancers (Couvineau Alain’s group)
Since few years ago, drugs targeting G protein-coupled receptors GPCRs are shown to have excellent therapeutic benefits. In this context, our project is to study the role and clinical interest of GPCRs in particular orexin receptors (OXR), in digestive cancer development. Orexins, hypothalamic peptides, interacted with two GPCR (OX1R and OX2R). They regulate sleep, wakefulness, feeding, breathing, reward system, or drug addiction. We have shown that orexins induced a robust apoptosis in colon cancer cell lines which expressed OX1R. This cell death was mediated through ITIM sequence resulting in the recruitment and theactivation of the SHP-2, leading to a mitochondrial apoptosis. Furthermore, we have demonstrated that OX1R is aberrantly expressed in digestive cancers including colon cancers, pancreas cancers and liver cancers but inversely is not present in normal tissue. Moreover we have demonstrated that orexins have strong anti-tumoral effects in pre-clinical models of digestive cancers.
Our project aims:
To study the presence of of orexins and theirreceptors in various pre-cancerous and inflammatory states in the digestive tract, especially in the early stage of colonic and pancreatic carcinogenesis encompassing IBD and adenomas (polyps, PanIN). To evaluate the dynamic role of OX1R during the carcinogenesis, we will use various mouse models such as chemically colitis- induced mice (DSS) and/or genetically modified mice as EXCY2 model (E. Ogier-Denis, Paris) or IL10-/- (A. Jarry, Nantes) which develop spontaneously colitis-associated cancer. Xenografted models produced from patient resected tumors (xenograft derived patient, PDX) are currently in progress
OX1R expression in pancreatic adenocarcinoma
To study the role of orexins on isolated cells and/or tumors explants maintained in culture from resected patient tumors (colon, pancreas and liver). This innovative approach developed in our team, will allow us to determine the anti-tumoral effect of orexins ex vivo by measuring various markers of apoptosis, hypoxia and angiogenesis.
To study the OX1R signaling pathways in which the recruitment of SHP2 and oxidative stress activation (p38, ROS, NRF2….) induces a mitochondrial apoptosis leading to anti-tumoral effects of
orexins and also their anti-inflammatory properties.
To define the structure-function relationships of orexins and OX1R in order to develop new agonists having a therapeutical interest in the treatment of digestive cancers (colon, pancreas and liver). Indeed, the determination of residues involving in the interaction between orexins and OX1R using alanine-scanning, side directed mutagenesis associated to 3D molecular modeling approaches will allow us to design, in collaboration with pharmaceutical industry, new molecules. Moreover, alternative strategies such as the production of antibodies mimicking the agonist properties of orexins will be planned
Anti-tumoral effect of orexins in xenografted colon cancer cell line (HT-29)
This project could lead :
2) To define the potential role of orexins in the treatment of digestive cancers and IBD;
3) To design innovative molecules having therapeutical interest.
3D model of OX1R