title: ATR-Chk2 signaling in p53 activation and DNA damage response during cisplatin-induced apoptosis.
abstract: Cisplatin is one of the most effective anti-cancer drugs; however, the use of cisplatin is limited by its toxicity in normal tissues, particularly injury of the kidneys. The mechanisms underlying the therapeutic effects of cisplatin in cancers and side effects in normal tissues are largely unclear. Recent work has suggested a role for p53 in cisplatin-induced renal cell apoptosis and kidney injury; however, the signaling pathway leading to p53 activation and renal apoptosis is unknown. Here we demonstrate an early DNA damage response during cisplatin treatment of renal cells and tissues. Importantly, in the DNA damage response, we demonstrate a critical role for ATR, but not ATM (ataxia telangiectasia mutated) or DNA-PK (DNA-dependent protein kinase), in cisplatin-induced p53 activation and apoptosis. We show that ATR is specifically activated during cisplatin treatment and co-localizes with H2AX, forming nuclear foci at the site of DNA damage. Blockade of ATR with a dominant-negative mutant inhibits cisplatin-induced p53 activation and renal cell apoptosis. Consistently, cisplatin-induced p53 activation and apoptosis are suppressed in ATR-deficient fibroblasts. Downstream of ATR, both Chk1 and Chk2 are phosphorylated during cisplatin treatment in an ATR-dependent manner. Interestingly, following phosphorylation, Chk1 is degraded via the proteosomal pathway, whereas Chk2 is activated. Inhibition of Chk2 by a dominant-negative mutant or gene deficiency attenuates cisplatin-induced p53 activation and apoptosis. In vivo in C57BL/6 mice, ATR and Chk2 are activated in renal tissues following cisplatin treatment. Together, the results suggest an important role for the DNA damage response mediated by ATR-Chk2 in p53 activation and renal cell apoptosis during cisplatin nephrotoxicity.
authors.affiliation: Department of Cellular Biology and Anatomy, Center for Biotechnology and Genomic Medicine, Medical College of Georgia and Charlie Norwood Veterans Affairs Medical Center, 1459 Laney Walker Boulevard, Augusta, GA 30912, USA.
authors.forename: Navjotsingh
authors.initials: N
authors.lastname: Pabla
authors.forename: Shuang
authors.initials: S
authors.lastname: Huang
authors.forename: Qing-Sheng
authors.initials: QS
authors.lastname: Mi
authors.forename: Rene
authors.initials: R
authors.lastname: Daniel
authors.forename: Zheng
authors.initials: Z
authors.lastname: Dong
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000009:adverse effects* / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002461:Cell Line, Transformed; D000071877:Checkpoint Kinase 1; D064447:Checkpoint Kinase 2; D002945:Cisplatin / Q000009:adverse effects* / Q000494:pharmacology; D004249:DNA Damage / Q000187:drug effects* / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D006657:Histones / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007674:Kidney Diseases / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism; D007687:Kidney Tubules, Proximal / Q000293:injuries / Q000378:metabolism*; D009369:Neoplasms / Q000150:complications / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000235:genetics / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects* / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C468783:H2AX protein, human; D006657:Histones; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; D011494:Protein Kinases; C576897:Atr protein, mouse; D064447:Checkpoint Kinase 2; C576324:ATM protein, human; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C576325:Atm protein, mouse; C000605867:CHEK1 protein, human; C578634:CHEK2 protein, human; D000071877:Checkpoint Kinase 1; C000605869:Chek1 protein, mouse; C000605871:Chek1 protein, rat; C578633:Chek2 protein, mouse; C578632:Chek2 protein, rat; D017346:Protein Serine-Threonine Kinases; D046988:Proteasome Endopeptidase Complex; D002945:Cisplatin