TRPC3 shapes the ER-mitochondria Ca 2+ transfer characterizing tumour-promoting senescence
Valerio Farfariello, Dmitri V. Gordienko, Lina Mesilmany, Yasmine Touil, Emmanuelle Germain, Ingrid Fliniaux, Emilie Desruelles, Dimitra Gkika, Morad Roudbaraki, George Shapovalov, Lucile Noyer, Mathilde Lebas, Laurent Allart, Nathalie Zienthal-Gelus, Oksana Iamshanova, Franck Bonardi, Martin Figeac, William Laine, Jerome Kluza, Philippe Marchetti, Bruno Quesnel, Daniel Metzger, David Bernard, Jan B. Parys, Loïc Lemonnier & Natalia Prevarskaya
Cellular senescence is implicated in a great number of diseases including cancer. Although alterations in mitochondrial metabolism were reported as senescence drivers, the underlying mechanisms remain elusive. We report the mechanism altering mitochondrial function and OXPHOS in stress-induced senescent fibroblasts. We demonstrate that TRPC3 protein, acting as a controller of mitochondrial Ca2+ load via negative regulation of IP3 receptor-mediated Ca2+ release, is down regulated in senescence regardless of the type of senescence inducer. This remodelling promotes cytosolic/mitochondrial Ca2+ oscillations and elevates mitochondrial Ca2+ load, mitochondrial oxygen consumption rate and oxidative phosphorylation. Re-expression of TRPC3 in senescent cells diminishes mitochondrial Ca2+ load and promotes escape from OIS-induced senescence. Cellular senescence evoked by TRPC3 downregulation in stromal cells displays a proinflammatory and tumour-promoting secretome that encourages cancer epithelial cell proliferation and tumour growth in vivo. Altogether, our results unravel the mechanism contributing to pro-tumour behaviour of senescent cells.