PU-PH, rattaché à l’Université de Franche-Comté.
Directeur de l’unité INSERM U1098 RIGHT à Besançon.
contact : Julien Faget ou Marie-Alix Poul ou Julie Constanzo
Centre de Recherche en Cancérologie de Toulouse (CRCT)-UMR 1037
contact : Christel Larbouret (Inserm-IRCM)
The fibroblastic stroma comprises most of pancreatic adenocarcinoma mass and is remarkably devoid of functional blood vessels leaving an unresolved question of how pancreatic cancer cells obtain their essential metabolites and especially water-insoluble lipids. Contrary to the previously held assumption that cancer cells uptake lipids directly from the interstitial fluid, we have found a critical role for cancer-associated fibroblasts (CAFs) to obtain and transfer blood-borne lipid particles to cancer cells via trogocytosis, a process of “nibbling” of plasma membranes between two cells engaged in synapse-like membrane contacts. Whereas trogocytosis has been described in normal development, the biochemical and signaling regulators of trogocytosis between CAFs and PDAC cells have not been defined. We determined that CAF membrane trogocytosis is triggered by externalized phosphatidylserine (PtdSer), and blockade of PtdSer in vitro transiently deters trogocytic uptake of CAF membranes. We have also discovered a phospholipid scramblase anoctamin 6 (ANO6) expressed in CAFs as the essential trogocytosis regulator to promote cancer cell survival. Mechanistically, CAF-cancer cell membrane contacts induce cytosolic calcium influx via Orai channels, which activates ANO6 and results in phosphatidylserine exposure on CAFs. As a promising therapy target, ANO6 protein is highly expressed in PDAC tumor mass in cancer cells, endothelial cells and CAFs and is a negative prognostic biomarker for survival. Depletion of ANO6 in co-implanted CAFs dramatically reduced the growth of orthotopic pancreatic tumor grafts. Furthermore, pharmacologic inhibitors of ANO6 with clinically available antibiotics niclosamide or clofazimine potently blocked cholesterol uptake in vivo by PDAC cells.
Director of Biology, NovalGen Ltd / Research Fellow, University College London – Cancer Institut
contact : P. Martineau (IRCM)
Centre de Recherche sur l'Inflammation - UMRS 1139 INSERM (PARIS)
contact : P. MARTINEAU (IRCM-Inserm)
Instituto de Investigación de Enfermedades Raras (IIER-ISCIII) / Unidad de Enfermedades Humanas en Drosophila (MEHD). Madrid
contact : A/ Maraver (IRCM)
INSERM U1242, Université de Rennes, Rennes, France. Centre de Lutte Contre le Cancer Eugène Marquis, Rennes, France.
host : Antonio Maraver (IRCM-Inserm)
Proteostasis imbalance is emerging as a major hallmark of cancer, driving tumor aggressiveness. Genetic and pharmacological evidence suggest that the endoplasmic reticulum (ER), a major site for protein folding and quality control, plays a critical role in cancer development. This concept has been validated in triple negative breast cancer, prostate cancer as well as in glioblastoma multiform (GB), the most lethal primary brain cancer with an overall survival of 15 months and no effective treatment. We demonstrated that the ER stress sensor IRE1 contributes to GB progression, impacting tissue invasion and tumor vascularization. IRE1 is a dual Kinase/RNase that signals by catalyzing the non-conventional splicing of the mRNA encoding the transcription factor XBP1, and in addition by regulating RNA stability through a process known as Regulated IRE1 Dependent Decay (RIDD). We further investigated the contribution of IRE1 signaling to GB and defined a specific expression signature that when confronted to human GB transcriptomes showed the antagonistic roles of XBP1 mRNA splicing and RIDD on tumor characteristics and outcomes. Moreover, using this signature we have explored the role of IRE1 signaling in tumor cells in reshaping the tumor microenvironment. These data identified IRE1 as an actionable therapeutic target which allowed us to use develop pharmacological approaches to enhance the efficacy of GB standard of care in mouse models.