title: Downregulation of bcl-xL is relevant to UV-induced apoptosis in fibroblasts.
abstract: Exposure to ultraviolet light (UV) induces apoptosis in mammalian cells. The caspase group of proteases is required for the apoptosis. This pathway is initiated by a release of cytochrome c from the mitochondria into the cytosol. Several Bcl-2 family proteins can regulate the release of cytochrome c by stabilizing the mitochondrial membrane. Here we show that expression of the endogenous bcl-xL was strongly downregulated in NIH3T3 cells within 2 h after UV-C irradiation, and that of bax was upregulated from 8 h after irradiation. Apoptosis was induced in more than 50% of the NIH3T3 cells 48 h after irradiation. Constitutive overexpression of bcl-xL in NIH3T3 cells protected the UV-induced apoptosis by preventing the loss of mitochondrial membrane potential and the activation of caspase 9. These results suggest that downregulation of Bcl-xL is relevant to UV-induced apoptosis of fibroblasts.
mesh_terms: D016475:3T3 Cells; D000818:Animals; D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis / Q000528:radiation effects*; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism / Q000528:radiation effects; D002470:Cell Survival / Q000528:radiation effects; D015536:Down-Regulation / Q000528:radiation effects*; D004789:Enzyme Activation; D005347:Fibroblasts; D008564:Membrane Potentials / Q000528:radiation effects; D051379:Mice; D008928:Mitochondria / Q000528:radiation effects; D011518:Proto-Oncogene Proteins / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics* / Q000502:physiology / Q000528:radiation effects; D014466:Ultraviolet Rays; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein
chemical_list: D017304:Annexin A5; C494827:Bax protein, mouse; C494812:Bcl2l1 protein, mouse; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; C506434:Casp9 protein, mouse; D053453:Caspase 9; D020169:Caspases