Implication du stress oxydant mitochondrial et de la surcharge hépatique en fer dans la survenue du carcinome hépatique en fer dans la survenue du carcinome hépatocellulaire développé sur cirrhose alcoolique

L identification de facteurs influençant le risque de développer un carcinome hépatocellulaire (CHC) chez les malades ayant une cirrhose est cruciale. Deux grandes voies de la carcinogenèse hépatique ont été abordées dans ces différents travaux : le stress oxydant mitochondrial et le métabolisme du fer, par le biais de l étude de mutations et polymorphismes génétiques chez des malades ayant une cirrhose et suivis prospectivement. Nous avons pu observer chez des malades ayant une cirrhose alcoolique que l hétérogénéité génétique de certaines enzymes anti-oxydantes mitochondriales (MnSOD et GPx1) influençait le risque de survenue du CHC, probablement par le biais d une accumulation de peroxyde d hydrogène. Par ailleurs, cette hétérogénéité génétique était associée à une surcharge hépatique en fer chez les malades supposés forts accumulateurs de peroxyde d hydrogène ; cette association était retrouvée dans un modèle cellulaire d hépatome humain transfecté par les différents variants génétiques de la MnSOD et s accompagnait de variations de molécules impliquées dans l homéostasie du fer (récepteurs de la transferrine 1 and 2, hepcidine, ferritine, frataxine). Enfin, cette surcharge hépatique en fer était associée chez les malades à un risque accru de développer un CHC et était influencée par le portage de la mutation C282Y du gène HFE. A l inverse, nous n avons pas observé d influence de ces hétérogénéités génétiques et de la surcharge hépatique en fer sur le risque de survenue du CHC chez des malades ayant une cirrhose virale C.Identification of factors influencing the risk of hepatocellular carcinoma occurrence (HCC) in patients with cirrhosis is of major interest. We studied two particular carcinogenesis pathways: mitochondrial oxidative stress and iron homeostasis, through genetic mutations and polymorphisms in prospectively followed-up cirrhotic patients. In patients with alcoholic cirrhosis, antioxidant enzymes genetic heterogeneity (MnSOD and GPx1) influenced the risk of HCC occurrence, presumably by modulating hydrogen peroxide accumulation. This genetic heterogeneity was associated with hepatic iron overload in patients with supposively high hydrogen peroxide accumulation; this finding was reproduced in a model of human hepatoma cell line transfected with MnSOD genetic variants and was associated with changes in expression of various molecules involved in iron homeostasis (transferrin receptors 1 and 2, hepcidin, ferritin, frataxin). Finally, hepatic iron overload was associated in these patients with higher HCC occurrence and was influenced by C282Y HFE gene mutation carriage. Conversely, we did not observe any influence of this genetic heterogeneity or hepatic iron overload on the risk of HCC occurrence in patients with viral C-related cirrhosis.PARIS13-BU Sciences (930792102) / SudocSudocFranceF

La liaison de SDF-1/CXCL au Syndécane-4

PARIS13-BU Sciences (930792102) / SudocSudocFranceF

Mise en évidence d'interactions spécifiques entre des glycoprotéines naturelles, l'alpha-foetoprotéine ou l'alpha-1 acide glycoprotéine, et ccr5 exprime à la membrane de macrophages humains en culture primaire

PARIS13-BU Sciences (930792102) / SudocSudocFranceF

Glycosaminoglycans and syndecan-4 are involved in SDF-1/CXCL12-mediated invasion of human epitheloid carcinoma HeLa cells.

International audienceBACKGROUND: In addition to their physiologic effects in inflammation and angiogenesis, chemokines are involved in cancer pathology. The CXC-chemokine stromal cell-derived factor-1 (SDF-1)/CXCL12 mediates its biological activities through activation of G protein-coupled receptor CXCR4 and binds to glycosaminoglycans (GAGs). METHODS: Using Bio-coat cell migration chambers, specific antagonists, flow cytometry and RNA interference, we evaluate the involvement of heparan sulfate proteoglycans (HSPG) in the SDF-1/CXCL12-induced invasion of human cervix epitheloid carcinoma HeLa cells. RESULTS: The SDF-1/CXCL12-induced cell invasion is dependent on CXCR4. Furthermore, Protein Kinase C delta (PKC delta) and c-jun NH2-terminal kinase/stress-activated protein kinase (JNK/SAPK) are implicated in this event, but not extracellular signal-regulated kinase (ERK) 1/2. Moreover, the invasion of HeLa cells induced by SDF-1/CXCL12 was dependent on matrix metalloproteinase-9 (MMP-9). The pre-incubation of HeLa cells with heparin or with anti-heparan sulfate antibodies or with beta-d-xyloside inhibited SDF-1/CXCL12-mediated cell invasion. Furthermore, the down-regulation of syndecan-4, a heparan sulfate proteoglycan, decreased SDF-1/CXCL12-mediated HeLa cell invasion. CONCLUSION: GAGs, probably on syndecan-4, are involved in SDF-1/CXCL12-mediated cell chemotaxis. GENERAL SIGNIFICANCE: These data suggest that targeting the glycosaminoglycan/chemokine interaction could be a new therapeutic approach for carcinomas in which SDF-1/CXCL12 is involved

Low molecular weight fucoidan prevents intimal hyperplasia in rat injured thoracic aorta through the modulation of matrix metalloproteinase-2 expression.

International audienceThe therapeutic potential of low molecular-weight fucoidan (LMWF), a sulfated polysaccharide extracted from brown seaweed was investigated on vascular smooth muscle cell (VSMC) and human vascular endothelial cell (HUV-EC-C) proliferation and migration in vitro and in a rat model of intimal hyperplasia. Sprague-Dawley rats were subjected to balloon injury in the thoracic aorta followed by two weeks' treatment with either LMWF (5mg/kg/day) or vehicle. Morphological analysis and proliferating cell nuclear antigen immunostaining at day 14 indicated that LMWF prevented intimal hyperplasia in rat thoracic aorta as compared with vehicle (neo-intima area, 3±0.50 versus 5±0.30mm, <0.01). In situ zymography showed that LMWF significantly decreased the activity of matrix metalloproteinase (MMP)-2 in the neo-intima compared to vehicle. The in vitro study demonstrated that 10μg/ml LMWF increased HUV-EC-C migration by 45±5% but reduced VSMC migration by 40±3%. LMWF also increased MMP-2 mRNA expression in HUV-EC-Cs and reduced it in VSMCs. MMP-2 level in the conditioned medium from cells incubated with 10μg/ml LMWF was 5.4-fold higher in HUV-EC-C, but 6-fold lower in VSMCs than in untreated control cells. Furthermore, decreasing MMP-2 expression in HUV-EC-Cs or VSMCs by RNA interference resulted in reduced LMWF-induced effects on cell migration

Chemokine system polymorphisms, survival and hepatocellular carcinoma occurrence in patients with hepatitis C virus-related cirrhosis

AIM: To explore the influence of polymorphisms in genes encoding for the chemokines Stromal cell-Derived Factor-1 (SDF-1)/CXCL12 and Monocyte Chemotactic Protein-1 (MCP-1)/CCL2, or for the chemokine receptor CCR5 on the risks of liver-related death and hepatocellular carcinoma (HCC) occurrence in hepatitis C virus (HCV)-infected patients

Syndecan-1 and syndecan-4 are involved in RANTES/CCL5-induced migration and invasion of human hepatoma cells

International audienceBackgroundWe previously demonstrated that the CC-chemokine Regulated upon Activation, Normal T cell Expressed and Secreted (RANTES)/CCL5 exerts pro-tumoral effects on human hepatoma Huh7 cells through its G protein-coupled receptor, CCR1. Glycosaminoglycans play major roles in these biological events.MethodsIn the present study, we explored 1/ the signalling pathways underlying RANTES/CCL5-mediated hepatoma cell migration or invasion by the use of specific pharmacological inhibitors, 2/ the role of RANTES/CCL5 oligomerization in these effects by using a dimeric RANTES/CCL5, 3/ the possible involvement of two membrane heparan sulfate proteoglycans, syndecan-1 (SDC-1) and syndecan-4 (SDC-4) in RANTES/CCL5-induced cell chemotaxis and spreading by pre-incubating cells with specific antibodies or by reducing SDC-1 or -4 expression by RNA interference.Results and conclusionThe present data suggest that focal adhesion kinase phosphorylation, phosphoinositide 3-kinase-, mitogen-activated protein kinase- and Rho kinase activations are involved in RANTES/CCL5 pro-tumoral effects on Huh7 cells. Interference with oligomerization of the chemokine reduced RANTES/CCL5-mediated cell chemotaxis. This study also indicates that SDC-1 and -4 may be required for HepG2, Hep3B and Huh7 human hepatoma cell migration, invasion or spreading induced by the chemokine. These results also further demonstrate the involvement of glycosaminoglycans as the glycosaminoglycan-binding deficient RANTES/CCL5 variant, in which arginine 47 was replaced by lysine, was devoid of effect.General significanceThe modulation of RANTES/CCL5-mediated cellular effects by targeting the chemokine-syndecan interaction could represent a new therapeutic approach for hepatocellular carcinoma