title: Cisplatin-induced DNA damage activates replication checkpoint signaling components that differentially affect tumor cell survival.
abstract: Cisplatin and other platinating agents are some of the most widely used chemotherapy agents. These drugs exert their antiproliferative effects by creating intrastrand and interstrand DNA cross-links, which block DNA replication. The cross-links mobilize signaling and repair pathways, including the Rad9-Hus1-Rad1-ATR-Chk1 pathway, a pathway that helps tumor cells survive the DNA damage inflicted by many chemotherapy agents. Here we show that Rad9 and ATR play critical roles in helping tumor cells survive cisplatin treatment. However, depleting Chk1 with small interfering RNA or inhibiting Chk1 with 3-(carbamoylamino)-5-(3-fluorophenyl)-N-(3-piperidyl)thiophene-2-carboxamide (AZD7762) did not sensitize these cells to cisplatin, oxaliplatin, or carboplatin. Moreover, when Rad18, Rad51, BRCA1, BRCA2, or FancD2 was disabled, Chk1 depletion did not further sensitize the cells to cisplatin. In fact, Chk1 depletion reversed the sensitivity seen when Rad18 was disabled. Collectively, these studies suggest that the pharmacological manipulation of Chk1 may not be an effective strategy to sensitize tumors to platinating agents.
authors.affiliation: Department of Molecular Pharmacology & Experimental Therapeutics and Division of Oncology Research, Mayo Clinic, College of Medicine, Rochester, MN 55905, USA.
authors.forename: Jill M
authors.initials: JM
authors.lastname: Wagner
authors.forename: Larry M
authors.initials: LM
authors.lastname: Karnitz
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000502:physiology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D000071877:Checkpoint Kinase 1; D002945:Cisplatin / Q000494:pharmacology*; D004249:DNA Damage; D004260:DNA Repair / Q000187:drug effects; D006801:Humans; D011494:Protein Kinases / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000502:physiology; D016196:S Phase / Q000187:drug effects
chemical_list: D000970:Antineoplastic Agents; D018797:Cell Cycle Proteins; C069930:rad9 protein; D011494:Protein Kinases; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; D017346:Protein Serine-Threonine Kinases; D002945:Cisplatin