title: Checkpoint kinase inhibitor AZD7762 overcomes cisplatin resistance in clear cell carcinoma of the ovary.
abstract: OBJECTIVE
  Checkpoint kinase (Chk) inhibitors are thought to increase the cytotoxic effects of DNA-damaging agents and are undergoing clinical trials. The present study was aimed to assess the potential to use the Chk1 and Chk2 inhibitor, AZD7762, with other anticancer agents in chemotherapy to treat ovarian clear cell carcinoma.
  
  
  METHODS
  Four ovarian clear cell carcinoma cell lines were used in this study. We treated the cells with AZD7762 and anticancer agents, then assessed cell viability, cell cycle distribution, apoptosis, and the expression of protein in apoptotic pathways and molecules downstream of the Chk signaling pathways. We also investigated the effects of these drug combinations on tumor growth in a nude mouse xenograft model.
  
  
  RESULTS
  Synergistic effects from the combination of AZD7762 and cisplatin were observed in all 4 cell lines. However, we observed additive effects when AZD7762 was combined with paclitaxel on all cell lines tested. AZD7762 effectively suppressed the Chk signaling pathways activated by cisplatin, dramatically enhanced expression of phosphorylated H2A.X, cleaved caspase 9 and PARP, decreased the proportion of cells in the gap 0/ gap 1 phase and the synthesis-phase fraction, and increased apoptotic cells. Combinations of small interfering RNA against Chk 1 and small interfering RNA against Chk2 enhanced the cytotoxic effect of cisplatin in both RMG-I and KK cells. Finally, treating mice-bearing RMG-I with AZD7762 and cisplatin significantly suppressed growth of tumors in a xenograft model.
  
  
  CONCLUSIONS
  The present study indicates that chemotherapy with AZD7762 and cisplatin should be explored as a treatment modality for women with ovarian clear cell carcinoma.
authors.affiliation: *Department of Obstetrics and Gynecology, Tottori University School of Medicine, and †Tottori University Hospital Cancer Center, Yonago, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Itamochi
authors.forename: Mayumi
authors.initials: M
authors.lastname: Nishimura
authors.forename: Nao
authors.initials: N
authors.lastname: Oumi
authors.forename: Misaki
authors.initials: M
authors.lastname: Kato
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Oishi
authors.forename: Muneaki
authors.initials: M
authors.lastname: Shimada
authors.forename: Shinya
authors.initials: S
authors.lastname: Sato
authors.forename: Jun
authors.initials: J
authors.lastname: Naniwa
authors.forename: Seiya
authors.initials: S
authors.lastname: Sato
authors.forename: Akiko
authors.initials: A
authors.lastname: Kudoh
authors.forename: Junzo
authors.initials: J
authors.lastname: Kigawa
authors.forename: Tasuku
authors.initials: T
authors.lastname: Harada
mesh_terms: D018262:Adenocarcinoma, Clear Cell / Q000188:drug therapy*; D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000627:therapeutic use*; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D004357:Drug Synergism; D005260:Female; D051379:Mice; D008819:Mice, Nude; D010051:Ovarian Neoplasms / Q000188:drug therapy*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D013876:Thiophenes / Q000494:pharmacology / Q000627:therapeutic use*; D014508:Urea / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D023041:Xenograft Model Antitumor Assays
chemical_list: C532363:3-(carbamoylamino)-5-(3-fluorophenyl)-N-(3-piperidyl)thiophene-2-carboxamide; D000970:Antineoplastic Agents; D047428:Protein Kinase Inhibitors; D013876:Thiophenes; D014508:Urea; D002945:Cisplatin