Étude des couples chimiokines/récepteurs comme nouvelles cibles thérapeutiques des cancers colorectaux métastasés (études précliniques)

Avec 42 000 nouveaux cas diagnostiqués en 2012, le cancer colorectal (CCR) représente en France le troisième cancer en termes d incidence. Les métastases, qui surviennent principalement au niveau du foie et des poumons, en constituent la principale cause de décès. Malgré les progrès récents de la chimiothérapie et des agents ciblés, le taux de survie à 5 ans des patients présentant un CCR métastasé reste faible. Aujourd hui, la résection chirurgicale est le seul traitement curatif, cependant moins de 20% des patients porteurs de métastases sont opérables. Il existe donc un grand nombre de patients présentant un CCR métastasé pour lequel aucun traitement curatif ne peut être proposé. La formation des métastases à partir d une tumeur primaire résulte d une longue série d étapes séquentielles liées les unes aux autres. L issue de ce processus dépend à la fois des propriétés intrinsèques des cellules tumorales et de la réponse de l hôte. Il a récemment été montré que les couples chimiokines/récepteurs interviennent dans le contrôle des différentes étapes de la progression tumorale.Le projet de recherche développé au cours de mon travail de thèse avait pour objectif d utiliser les chimiokines et leurs récepteurs dans de nouvelles stratégies thérapeutiques pour bloquer et/ou éradiquer les métastases hépatiques et pulmonaires des CCRs. Le travail s est articulé selon deux axes dans lesquels nous avons montré d une part que, le blocage du récepteur de chimiokines CXCR7 permet de limiter les métastases pulmonaires de CCRs et d autre part que, le transfert de gène codant CX3CL1 au niveau du foie entraîne une réponse anti-tumorale efficace dans les métastases hépatiques de CCRs.With 42 000 newly-diagnosed patients in 2012, the colorectal cancer (CRC) represents the third type of cancer in terms of incidence in France. The leading cause of death from CRC is the development of metastases and these metastases will occur mostly within the liver (50% of the patients) and within the lungs (15%). Despite recent progress, notably in the chemotherapies now used and the targeted agents, the rate of 5-years survival for late stage CRC remains low. Nowadays, the surgical resection is the only curative treatment proposed to patients with metastatic CRC, however less than 20% of them have an operable tumour. There is therefore a high number of patients for whom no cure is currently available. A primary tumour s dissemination to a second organ is the result of a long process made of numerous cross-linked steps. The final outcome of this process depends on the intrinsic properties of tumour cells as well as the host response. Recently, it has been shown that the chemokine-chemokine receptor pairs (initially described as regulating the leukocyte migration) play crucial roles in the various stages involved in tumour progression. The aim of the research project developed during my PhD was to assess the use of the chemokines and their receptors in new therapeutic strategies to block and/or eradicate the hepatic and pulmonary metastases of CRC. Our work has been organized along two main lines of approach. We have shown that the blockage of the CXCR7 chemokine receptor enables the limitation of the CRC metastases within the lungs and that the CX3CL1 gene transfer into the hepatocytes leads to an efficient anti-tumor response in the CRC metastases within the liver.NICE-Bibliotheque electronique (060889901) / SudocSudocFranceF

CCL5 Neutralization Restricts Cancer Growth and Potentiates the Targeting of PDGFRβ in Colorectal Carcinoma

Increased CCL5 levels are markers of an unfavourable outcome in patients with melanoma, breast, cervical, prostate, gastric or pancreatic cancer. Here, we have assessed the role played by CCL5/CCR5 interactions in the development of colon cancer. To do so, we have examined a number of human colorectal carcinoma clinical specimens and found CCL5 and its receptors over-expressed within primary as well as liver and pulmonary metastases of patients compared to healthy tissues. In vitro, CCL5 increased the growth and migratory responses of colon cancer cells from both human and mouse origins. In addition, systemic treatment of mice with CCL5-directed antibodies reduced the extent of development of subcutaneous colon tumors, of liver metastases and of peritoneal carcinosis. Consistently, we found increased numbers of CD45-immunoreactive cells within the stroma of the remaining lesions as well as at the interface with the healthy tissue. In contrast, selective targeting of CCR5 through administration of TAK-779, a CCR5 antagonist, only partially compromised colon cancer progression. Furthermore, CCL5 neutralization rendered the tumors more sensitive to a PDGFRβ-directed strategy in mice, this combination regimen offering the greatest protection against liver metastases and suppressing macroscopic peritoneal carcinosis. Collectively, our data demonstrate the involvement of CCL5 in the pathogenesis of colorectal carcinoma and point to its potential value as a therapeutic target

Helicobacter pylori Infection of Gastrointestinal Epithelial Cells in vitro Induces Mesenchymal Stem Cell Migration through an NF-κB-Dependent Pathway

The role of bone marrow-derived mesenchymal stem cells (MSC) in the physiology of the gastrointestinal tract epithelium is currently not well established. These cells can be recruited in response to inflammation due to epithelial damage, home, and participate in tissue repair. In addition, in the case of tissue repair failure, these cells could transform and be at the origin of carcinomas. However, the chemoattractant molecules responsible for MSC recruitment and migration in response to epithelial damage, and particularly to Helicobacter pylori infection, remain unknown although the role of some chemokines has been suggested. This work aimed to get insight into the mechanisms of mouse MSC migration during in vitro infection of mouse gastrointestinal epithelial cells by H. pylori. Using a cell culture insert system, we showed that infection of gastrointestinal epithelial cells by different H. pylori strains is able to stimulate the migration of MSC. This mechanism involves the secretion by infected epithelial cells of multiple cytokines, with a major role of TNFα, mainly via a Nuclear Factor-kappa B-dependent pathway. This study provides the first evidence of the role of H. pylori infection in MSC migration and paves the way to a better understanding of the role of bone marrow-derived stem cells in gastric pathophysiology and carcinogenesis

Understanding the Progression of Bone Metastases to Identify Novel Therapeutic Targets

Bone is one of the most preferential target site for cancer metastases, particularly for prostate, breast, kidney, lung and thyroid primary tumours. Indeed, numerous chemical signals and growth factors produced by the bone microenvironment constitute factors promoting cancer cell invasion and aggression. After reviewing the different theories proposed to provide mechanism for metastatic progression, we report on the gene expression profile of bone-seeking cancer cells. We also discuss the cross-talk between the bone microenvironment and invading cells, which impacts on the tumour actions on surrounding bone tissue. Lastly, we detail therapies for bone metastases. Due to poor prognosis for patients, the strategies mainly aim at reducing the impact of skeletal-related events on patients’ quality of life. However, recent advances have led to a better understanding of molecular mechanisms underlying bone metastases progression, and therefore of novel therapeutic targets

Étude des mécanismes moléculaires impliqués au cours du recrutement des monocytes/macrophages dans les tissus (rôle des chimiokines)

Le recrutement des monocytes vers les tissus constitue un processus clef de la réponse inflammatoire de l'organisme dépendant de l'expression de chimiokines par les tissus. Nous avons identifié, dans la lignée monocytaire MonoMac6, les signaux induits par les chimiokines MCP-1 et s-FNK, puis étudié leur importance dans la migration transendothéliale des monocytes. Nous observons que MCP-1 et s-FNK stimulent les MAPKs : ERKs, SAPK1 et SAPK2. En revanche, les tyrosine kinases Syk et Src et les protéines G qui sont activées par ces chimiokines régulent différemment ces voies MAPKs. Par des expériences de migration en chambre, nous avons observé que les monocytes répondent en termes de migration au MCP-1, alors que s-FNK stimule leur adhérence à la fibronectine. L'utilisation d'inhibiteurs pharmacologiques et de toxines bactériennes nous a permis d'impliquer les SAPKs et les protéines Go/Gi dans les processus de migration transendothéliale des monocytes et d'adhérence. En revanche, les voies ERK et PI3K sont plus particulièrement impliquées dans le contrôle de l'adhésion. Le cytosquelette joue un rôle crucial à la fois dans les processus de migration et d'adhésion cellulaire, mais il intervient également dans la propagation des signaux mitogènes et des signaux d'activation. Nos travaux proposent un modèle expliquant comment la destructuration du réseau microtubulaire entraîne un état d'activation de la cellule caractérisé par la synthèse sélective d'IL-1. Ils décrivent les microtubules comme un lien moléculaire entre les protéines G trimériques et les protéines tyrosine kinases. En conclusion, nos travaux apportent un nouvel éclairage sur les mécanismes par lesquels les monocytes réagissent à leur environnement en termes de remodelage cytosquelettique, d'adhésion, de migration et de production de cytokines.NICE-BU Sciences (060882101) / SudocSudocFranceF

Evaluation du potentiel anti-tumoral de la fractalkine par transfert de gène dans un modèle de métastases hépatiques de cancer colique chez la souris (étude des mécanismes moléculaires impliqués dans le recrutement des leucocytes vers les sites inflammatoires, infectieux et tumoraux en réponse aux chimiokines)

WE TESTED THE EFFECT OF FRACTALKINE GENE TRANSFER ON THE DEVELOPMENT OF LIVER METASTASIS OF COLON CANCER IN MICE. OUR STRATEGY HAS CONSISTED IN INDUCING THE EXPRESSION OF FRACTALKINE BY MOUSE COLON ADENOCARCINOMA CELLS AND THEN IN EVALUATING THE TUMORIGENICITY OF THESE CELLS AFTER INJECTION UNDER THE LIVER CAPSULE. THE DEVELOPMENT OF FRACTALKINE EXPRESSING TUMORS IS DELAYED WHEN COMPARED TO PARENTAL TUMORS. THIS DELAY IS SUPPRESSED WHEN CD4+ OR CD8+ T LYMPHOCYTES ARE DEPLETED, AND REMAINS UNCHANGED WHEN NATURAL KILLER CELLS ARE ELIMINATED. THESE RESULTS SUGGEST THAT THE ANTITUMOR EFFECT OF FRACTALKINE RESULTS FROM THE INDUCTION OF A SPECIFIC IMMUNE RESPONSE. WE WERE ABLE TO OBSERVE A REDUCTION IN BOTH THE PRODUCTION AND ACTIVATION OF MMP2 AND MMP9 IN FRACTALKINE EXPRESSING TUMORS. THE NEGATIVE REGULATION OF MMPS ACTIVITY COULD REPRESENT AN ANTITUMOR MECHANISM ADDING ON TO THE IMMUNE RESPONSE. IN PARALLEL, WE STUDIED THE SIGNALING PATHWAYS INVOLVED IN THE RECRUITMENT OF LEUKOCYTES TO THE INFLAMMATORY, INFECTIOUS AND TUMOR SITES IN RESPONSE TO CHEMOKINES. WE DEMONSTRATED THAT FRACTALKINE PREVENTS THE MIGRATION OF MONOCYTES INDUCED BY AN OTHER CHEMOKINE, NAMELY MCP-1. THIS EFFECT SEEMS TO RESULT FROM THE INHIBITION OF SEVERAL PROTEINS INVOLVED IN THE TRANSDUCTION OF THE PROMIGRATORY SIGNAL OF MCP-1, AMONG WHICH PYK2 AND P38, AND FROM A REDUCTION IN MMP2 ACTIVATION. HOWEVER, FRACTALKINE STIMULATES THE MIGRATION OF NATURAL KILLER CELLS THROUGH A MECHANISM WHICH REQUIRES P38 ACTIVATION.NICE-BU Sciences (060882101) / SudocSudocFranceF

Idiopathic CD4 T Cell Lymphocytopenia: A Case of Overexpression of PD-1/PDL-1 and CTLA-4

International audienceIdiopathic CD4 T cell lymphocytopenia (ICL) is a rare entity characterized by CD4 T cell count of <300 cells/mm3 along with opportunistic infection for which T cell marker expression remains to be fully explored. We report an ICL case for which T lymphocyte phenotype and its costimulatory molecules expression was analyzed both ex vivo and after overnight stimulation through CD3/CD28. The ICL patient was compared to five healthy controls. We observed higher expression of inhibitory molecules PD-1/PDL-1 and CTLA-4 on CD4 T cells and increased regulatory T cells in ICL, along with high activation and low proliferation of CD4 T cells. The alteration in the expression of both the costimulatory pathway and the apoptotic pathway might participate to down-regulate both CD4 T cell functions and numbers observed in ICL

Understanding the Progression of Bone Metastases to Identify Novel Therapeutic Targets

Bone is one of the most preferential target site for cancer metastases, particularly for prostate, breast, kidney, lung and thyroid primary tumours. Indeed, numerous chemical signals and growth factors produced by the bone microenvironment constitute factors promoting cancer cell invasion and aggression. After reviewing the different theories proposed to provide mechanism for metastatic progression, we report on the gene expression profile of bone-seeking cancer cells. We also discuss the cross-talk between the bone microenvironment and invading cells, which impacts on the tumour actions on surrounding bone tissue. Lastly, we detail therapies for bone metastases. Due to poor prognosis for patients, the strategies mainly aim at reducing the impact of skeletal-related events on patients’ quality of life. However, recent advances have led to a better understanding of molecular mechanisms underlying bone metastases progression, and therefore of novel therapeutic targets

Therapeutic strategies for treating osteolytic bone metastases.

International audienceThe recent progress in oncologic management of patients with localized cancer or metastatic disease has permitted a significant improvement in life expectancy. Nevertheless, bone metastases and their consequent skeletal-related events (SREs) are still associated with unfavorable prognosis and greatly affect quality of life. Global management of these bone metastases includes traditional local approaches (surgery, radiotherapy, etc.) and systemic administration of chemotherapeutic agents. This review focuses on treatments specific for bone metastases and, in particular, on inhibitors of bone resorption that are effective for preventing and delaying the development of SREs