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.
- MeSH
- enzymy opravy DNA antagonisté a inhibitory genetika MeSH
- fibroblasty účinky záření MeSH
- kultivované buňky účinky záření MeSH
- nádorové buňky kultivované účinky léků účinky záření MeSH
- nemalobuněčný karcinom plic genetika radioterapie MeSH
- oprava DNA účinky léků MeSH
- proliferace buněk účinky záření MeSH
- radiosenzibilizující látky farmakologie izolace a purifikace terapeutické užití MeSH
- techniky in vitro MeSH
- Publikační typ
- práce podpořená grantem MeSH
- Publikační typ
- abstrakt z konference MeSH
We evaluated the impact of ataxia-telangiectasia mutated kinase inhibitor KU55933, DNA-dependent protein kinase inhibitor NU7441 and ataxia telangiectasia and rad3-related kinase inhibitor VE821 in human peripheral lymphocytes in vitro. The lymphocytes were divided into 5 groups: non-irradiated control, irradiated group (2 Gy) and 3 groups pretreated with inhibitors 30 min before irradiation. We used flow cytometry to evaluate phosphorylated H2AX (γ-H2AX) and cytotoxicity (Apoptest). Micronucleus assay was used to assess genotoxicity. After irradiation, γ-H2AX, incidence of micronuclei (MN), nucleoplasmatic bridges (NPBs) and nuclear buds in binuclear cells, MN in mononuclear cells and apoptosis were increased. KU55933 decreased γ-H2AX and inhibited ionizing radiation-induced cytotoxicity. NU7441 showed no effect on γ-H2AX but it significantly increased MN and NPBs in binuclear cells and apoptosis. VE821 decreased γ-H2AX, whereas genotoxicity and cytotoxicity were not affected. In conclusion, KU55933 protected lymphocytes, which might be employed to preserve the immune system during anticancer therapy. NU7441 radiosensitized lymphocytes, thus, undesirable side effects toward immune system could be expected. VE821 showed decrease of γ-H2AX with no radiosensitizing effects in our model likely due to p53 positive status, which underlies the concept of its application in p53 negative environment.
- Klíčová slova
- Účinky ionizujícího záření způsobené inhibitory ATM (KU55933), DNA-PK (NU7441) a ATR (VE821) na lymfocyty periferní krve,
- MeSH
- ATM protein účinky záření MeSH
- biomedicínský výzkum MeSH
- financování organizované MeSH
- fosfatidylinositol-3-kinasy antagonisté a inhibitory účinky záření MeSH
- fosforylace imunologie účinky záření MeSH
- histony chemie účinky záření MeSH
- ionizující záření * MeSH
- krevní a imunitní systémy cytologie imunologie účinky záření MeSH
- lidé MeSH
- lymfocyty * cytologie imunologie účinky záření MeSH
- statistika jako téma MeSH
- techniky in vitro MeSH
- Check Tag
- lidé MeSH
