Induction of p19INK4d in response to ultraviolet light improves DNA repair and confers resistance to apoptosis in neuroblastoma cells.
The genetic instability driving tumorigenesis is fueled by DNA damage and by errors made by the DNA replication. Upon DNA damage the cell organizes an integrated response not only by the classical DNA repair mechanisms but also involving mechanisms of replication, transcription, chromatin structure dynamics, cell cycle progression, and apoptosis. In the present study, we investigated the role of p19INK4d in the response driven by neuroblastoma cells against DNA injury caused by UV irradiation. We show that p19INK4d is the only INK4 protein whose expression is induced by UV light in neuroblastoma cells. Furthermore, p19INK4d translocation from cytoplasm to nucleus is observed after UV irradiation. Ectopic expression of p19INK4d clearly reduces the UV-induced apoptosis as well as enhances the cellular ability to repair the damaged DNA. It is clearly shown that DNA repair is the main target of p19INK4d effect and that diminished apoptosis is a downstream event. Importantly, experiments performed with CDK4 mutants suggest that these p19INK4d effects would be independent of its role as a cell cycle checkpoint gene. The results presented herein uncover a new role of p19INK4d as regulator of DNA-damage-induced apoptosis and suggest that it protects cells from undergoing apoptosis by allowing a more efficient DNA repair. We propose that, in addition to its role as cell cycle inhibitor, p19INK4d is involved in maintenance of DNA integrity and, therefore, would contribute to cancer prevention.
Ceruti
Julieta M
JM
Laboratorio de Biología Molecular, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria Pabellón II Piso 4, 1428 Buenos Aires, Argentina.
Scassa
María E
ME
Fló
Juan M
JM
Varone
Cecilia L
CL
Cánepa
Eduardo T
ET
D000818:Animals; D017209:Apoptosis / Q000528:radiation effects*; D002453:Cell Cycle / Q000528:radiation effects; D018797:Cell Cycle Proteins / Q000378:metabolism* / Q000528:radiation effects*; D045744:Cell Line, Tumor; D050764:Cyclin-Dependent Kinase Inhibitor p19; D004249:DNA Damage / Q000528:radiation effects*; D004260:DNA Repair / Q000502:physiology* / Q000528:radiation effects; D004261:DNA Replication / Q000528:radiation effects; D016193:G1 Phase / Q000528:radiation effects; D006801:Humans; D007700:Kinetics; D051379:Mice; D009447:Neuroblastoma; D021381:Protein Transport; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics / Q000302:isolation & purification; D014466:Ultraviolet Rays
C493974:CDKN2D protein, human; C493975:Cdkn2d protein, mouse; D018797:Cell Cycle Proteins; D050764:Cyclin-Dependent Kinase Inhibitor p19; D012333:RNA, Messenger; D012334:RNA, Neoplasm