Ataxia telangiectasia mutated and Rad3 related (ATR) protein kinase inhibition is synthetically lethal in XRCC1 deficient ovarian cancer cells

• Published in: PloS one 2013-02, Vol.8 (2), p.e57098-e57098
• Main Authors: Sultana, Rebeka, Abdel-Fatah, Tarek, Perry, Christina, Moseley, Paul, Albarakti, Nada, Mohan, Vivek, Seedhouse, Claire, Chan, Stephen, Madhusudan, Srinivasan
• Format: Article
• Language: English
• Subjects: Analysis; Animals; Annexin V; Apoptosis; Ataxia; Ataxia telangiectasia mutated protein; Ataxia Telangiectasia Mutated Proteins; Base excision repair; Base Sequence; Bioassay; Bioassays; Biology; Cancer; Cancer cells; Cancer therapies; Cell cycle; Cell Cycle Proteins - antagonists & inhibitors; Cell Line, Tumor; Chemotherapy; CHO Cells; Cisplatin; Cricetinae; Cricetulus; Cytotoxicity; Damage detection; Data processing; Deoxyribonucleic acid; DNA; DNA biosynthesis; DNA damage; DNA repair; DNA-Binding Proteins - genetics; Enzyme Inhibitors - pharmacology; Enzymes; Female; Flow cytometry; Genomes; Humans; Immunocytochemistry; Inhibition; Inhibitors; Intermediates; Ionizing radiation; Kinases; Laboratories; Lethality; Medicine; Multivariate analysis; Nucleotide excision repair; Oncology; Ovarian cancer; Ovarian carcinoma; Penicillin; Protein kinase; Protein kinases; Protein-Serine-Threonine Kinases - antagonists & inhibitors; Proteins; Repair; Replication forks; RNA, Small Interfering; Rodents; Single-stranded DNA; Studies; Telangiectasis; Toxicity; Tumors; X-ray Repair Cross Complementing Protein 1; XRCC1 protein
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0057098

Ataxia telangiectasia mutated and Rad3 Related (ATR) protein kinase is a key sensor of single-stranded DNA associated with stalled replication forks and repair intermediates generated during DNA repair. XRCC1 is a critical enzyme in single strand break repair and base excision repair. XRCC1-LIG3 complex is also an important contributor to the ligation step of the nucleotide excision repair response. In the current study, we investigated synthetic lethality in XRCC1 deficient and XRCC1 proficient Chinese Hamster ovary (CHO) and human ovarian cancer cells using ATR inhibitors (NU6027). In addition, we also investigated the ability of ATR inhibitors to potentiate cisplatin cytotoxicity in XRCC1 deficient and XRCC1 proficient CHO and human cancer cells. Clonogenic assays, alkaline COMET assays, γH2AX immunocytochemistry, FACS for cell cycle as well as FITC-annexin V flow cytometric analysis were performed. ATR inhibition is synthetically lethal in XRCC1 deficient cells as evidenced by increased cytotoxicity, accumulation of double strand DNA breaks, G2/M cell cycle arrest and increased apoptosis. Compared to cisplatin alone, combination of cisplatin and ATR inhibitor results in enhanced cytotoxicity in XRCC1 deficient cells compared to XRCC1 proficient cells. Our data provides evidence that ATR inhibition is suitable for synthetic lethality application and cisplatin chemopotentiation in XRCC1 deficient ovarian cancer cells.