J Appl Biomed 16:66-74, 2018 | DOI: 10.1016/j.jab.2017.10.008

DNA repair inhibitors as radiosensitizers in human lung cells

Kamila Ďurišová^a, Lucie Čecháková^a, Petr Jošt^b,c, Zuzana Šinkorová^a, Adéla Kmochová^a, Jaroslav Pejchal^a,b, Martin Ondrej^a, Jiřina Vávrová^a, Aleš Tichý^a,c,*

^a University of Defence in Brno, Faculty of Military Health Sciences in Hradec Králové, Department of Radiobiology, Hradec Králové, Czech Republic

^b University of Defence in Brno, Faculty of Military Health Sciences in Hradec Králové, Department of Toxicology and Military Pharmacy, Hradec Králové, Czech Republic

^c University Hospital Hradec Králové, Biomedical Research Centre, Hradec Králové, Czech Republic

The aim of this study was to compare the effects of DNA repair inhibitors in the context of radio-sensitization of human lung cells. The radio-sensitizing effects of NU7441 (1 mM), an inhibitor of DNA-dependent protein kinase (DNA-PK); KU55933 (10 μM), an inhibitor of ataxia-telangiectasia mutated kinase (ATM); and VE-821 (10 μM), an inhibitor of ATM-related kinase (ATR) were tested by the xCELLigence system for monitoring proliferation, fluorescence microscopy for DNA damage detection, flow-cytometry for cell cycle and apoptosis analysis and western blotting and ELISA for determination of DNA repair proteins. We employed normal human lung fibroblasts (NHLF, p53-wild-type) and non-small cell lung cancer cells (H1299, p53-negative). DNA-PK inhibition (by NU7441) in combination with ionizing radiation (IR) increased the number of double strand breaks (DSB), which persisted 72 h after irradiation in both cell lines. Additionally, NU7441 and KU55933 in combination with IR caused G2-arrest. ATR inhibitor (VE-821) together with IR markedly inhibited proliferation and induced G2/M arrest accompanied by apoptosis in H1299, but not in NHLF cells, and thus diminished DNA-repair of tumour cells but not normal lung fibroblasts. Our findings indicate that ATR inhibition could be a promising therapeutic strategy in p53-deficient lung tumours.

Keywords: DNA repair; DNA-PK; ATM; ATR; Inhibition; Ionizing radiation; Lung cancer

Received: December 12, 2016; Revised: May 23, 2017; Accepted: October 24, 2017; Published: February 1, 2018  Show citation