title: Bcl-3 regulates UVB-induced apoptosis.
abstract: B cell leukemia-3 (Bcl-3) has been defined as an anti-apoptotic gene; however, the exact mechanisms through which Bcl-3 influences apoptosis have been elusive. To determine the specific role of Bcl-3 in apoptosis, we evaluated the effect of its silencing on the expression of proteins involved in either the extrinsic or intrinsic apoptotic pathways induced by ultraviolet light B-mediated DNA damage. We found that, in Bcl-3-silenced cells, caspase-3, caspase-8 and caspase-9 activation is accelerated and tBid mitochondrial content is increased. It is important to note that, although mitochondrial Smac levels were reduced after UV exposure, the rate of reduction was slightly higher in Bcl-3 silenced cells than in control cells. Additionally, p53 levels diminished in Bcl-3 silenced cells compared to control cells, as did those of DNA-PK, a DNA repair protein. Altogether, our data indicate that Bcl-3 protects cells from apoptosis by regulating both apoptotic pathways.
authors.affiliation: National Institute of Cancerology, Av. San Fernando 22 Tlalpan, 14080 Mexico, Mexico.
authors.forename: Ingrid
authors.initials: I
authors.lastname: García
authors.forename: Gabriela
authors.initials: G
authors.lastname: Cosío
authors.forename: Floria
authors.initials: F
authors.lastname: Lizárraga
authors.forename: Gustavo
authors.initials: G
authors.lastname: Martínez-Ruiz
authors.forename: Jorge
authors.initials: J
authors.lastname: Meléndez-Zajgla
authors.forename: Gisela
authors.initials: G
authors.lastname: Ceballos
authors.forename: Magali
authors.initials: M
authors.lastname: Espinosa
authors.forename: Rosario
authors.initials: R
authors.lastname: Pacheco
authors.forename: Vilma
authors.initials: V
authors.lastname: Maldonado
mesh_terms: D017209:Apoptosis / Q000235:genetics* / Q000528:radiation effects*; D051017:Apoptosis Regulatory Proteins; D000081242:B-Cell Lymphoma 3 Protein; D051023:BH3 Interacting Domain Death Agonist Protein / Q000378:metabolism; D020169:Caspases / Q000378:metabolism; D004249:DNA Damage / Q000528:radiation effects; D020868:Gene Silencing; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D051017:Apoptosis Regulatory Proteins; D000081242:B-Cell Lymphoma 3 Protein; C000631344:BCL3 protein, human; D051023:BH3 Interacting Domain Death Agonist Protein; C412403:DIABLO protein, human; D047908:Intracellular Signaling Peptides and Proteins; D024101:Mitochondrial Proteins; D011518:Proto-Oncogene Proteins; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D020169:Caspases