Serpins Promote Cancer Cell Survival and Vascular Co-Option in Brain Metastasis
Menée à l'aide de modèles murins, cette étude met en évidence le rôle joué par les serpines dans la survie des cellules de métastases cérébrales d'un cancer du sein ou du poumon
Brain metastasis is an ominous complication of cancer, yet most cancer cells that infiltrate the brain die of unknown causes. Here, we identify plasmin from the reactive brain stroma as a defense against metastatic invasion, and plasminogen activator (PA) inhibitory serpins in cancer cells as a shield against this defense. Plasmin suppresses brain metastasis in two ways: by converting membrane-bound astrocytic FasL into a paracrine death signal for cancer cells, and by inactivating the axon pathfinding molecule L1CAM, which metastatic cells express for spreading along brain capillaries and for metastatic outgrowth. Brain metastatic cells from lung cancer and breast cancer express high levels of anti-PA serpins, including neuroserpin and serpin B2, to prevent plasmin generation and its metastasis-suppressive effects. By protecting cancer cells from death signals and fostering vascular co-option, anti-PA serpins provide a unifying mechanism for the initiation of brain metastasis in lung and breast cancers. "Metastatic cells in the brain survive and grow attached to capillaries "Plasmin from the reactive stroma mobilizes FasL to repel brain-infiltrating cells "Plasmin additionally prevents vascular cooption by cleaving cancer cell L1CAM "Brain metastatic cells express Serpins to prevent Plasmin production The serine protease plasmin protects the brain from metastasis by promoting cell death and inhibiting the spread of cancer cells along the vasculature. Successful brain metastatic cells express an inhibitory serpin that prevents plasmin generation.