Abstract
Inhibition of repair of X-ray-induced potentially lethal damage (PLD) could enhance the curability of radioresistant tumours. We have studied the effect of inhibitors of the enzyme poly (ADP-ribose) polymerase on X-ray PLD repair. Four classes of inhibitors are known: aromatic amides (e.g., 3-aminobenzamide), thymidine, nicotinamides and methyl xanthines (e.g., caffeine). Plateau-phase Chinese hamster ovary (HA-1) cultures were exposed to 10mM concentrations of thymidine, nicotinamide, 3-aminobenzamide (3-ABA) and caffeine prior to irradiation to 12 Gy in air, and then incubated with drug at 37 degrees C for varying times (0-6 h) prior to subculture. Irradiated cells without drug exhibited a 5-6 fold increase in survival over the 6 h period compared to cultures plated immediately after irradiation. Although none of the compounds proved cytotoxic to unirradiated controls over the 6.5 h exposure, all of the compounds except thymidine reduced the capacity of the cells to repair PLD. The order of the inhibitory effect was caffeine greater than 3-ABA greater than nicotinamide, and the inhibition was concentration dependent for nicotinamide and 3-ABA. We also studied the effect of 3-ABA on the radiation response of exponentially growing cells. 5mM 3-ABA for 2 h post-irradiation resulted in a dose-multiplicative sensitization reducing the D0 from 0.88 Gy to 0.69 Gy, indicating an involvement of poly (ADP-ribose) polymerase in the radiosensitivity of exponentially growing as well as plateau-phase cells.
Full text
PDF




Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Davies M. I., Shall S., Skidmore C. J. Poly(adenosine diphosphate ribose) polymerase and deoxyribonucleic acid damage [proceedings]. Biochem Soc Trans. 1977;5(4):949–950. doi: 10.1042/bst0050949. [DOI] [PubMed] [Google Scholar]
- Durkacz B. W., Omidiji O., Gray D. A., Shall S. (ADP-ribose)n participates in DNA excision repair. Nature. 1980 Feb 7;283(5747):593–596. doi: 10.1038/283593a0. [DOI] [PubMed] [Google Scholar]
- Edwards M. J., Taylor A. M. Unusual levels of (ADP-ribose)n and DNA synthesis in ataxia telangiectasia cells following gamma-ray irradiation. Nature. 1980 Oct 23;287(5784):745–747. doi: 10.1038/287745a0. [DOI] [PubMed] [Google Scholar]
- Hilz H., Stone P. Poly(ADP-ribose) and ADP-ribosylation of proteins. Rev Physiol Biochem Pharmacol. 1976;76:1-58, 177. doi: 10.1007/BFb0027686. [DOI] [PubMed] [Google Scholar]
- Iliakis G., Nüsse M., Bryant P. Effects of aphidicolin on cell proliferation, repair of potentially lethal damage and repair of DNA strand breaks in Ehrlich ascites tumour cells exposed to X-rays. Int J Radiat Biol Relat Stud Phys Chem Med. 1982 Oct;42(4):417–434. doi: 10.1080/09553008214551341. [DOI] [PubMed] [Google Scholar]
- Nduka N., Skidmore C. J., Shall S. The enhancement of cytotoxicity of N-methyl-N-nitrosourea and of gamma-radiation by inhibitors of poly(ADP-ribose) polymerase. Eur J Biochem. 1980 Apr;105(3):525–530. doi: 10.1111/j.1432-1033.1980.tb04528.x. [DOI] [PubMed] [Google Scholar]
- Preiss J., Schlaeger R., Hilz H. Specific inhibition of poly adpribose polymerase by thymidine and nicotinamide in HeLa cells. FEBS Lett. 1971 Dec 15;19(3):244–246. doi: 10.1016/0014-5793(71)80524-0. [DOI] [PubMed] [Google Scholar]
- Shall S., Goodwin P., Halldorsson H., Khan G., Skidmore C., Tsopanakis C. Post-synthetic modifications of nuclear macromolecules. Biochem Soc Symp. 1977;(42):103–116. [PubMed] [Google Scholar]
- Skidmore C. J., Davies M. I., Goodwin P. M., Halldorsson H., Lewis P. J., Shall S., Zia'ee A. A. The involvement of poly(ADP-ribose) polymerase in the degradation of NAD caused by gamma-radiation and N-methyl-N-nitrosourea. Eur J Biochem. 1979 Nov 1;101(1):135–142. doi: 10.1111/j.1432-1033.1979.tb04225.x. [DOI] [PubMed] [Google Scholar]
- Taylor Y. C., Bump E. A., Brown J. M. Studies on the mechanism of chemosensitization by misonidazole in vitro. Int J Radiat Oncol Biol Phys. 1982 Mar-Apr;8(3-4):705–708. doi: 10.1016/0360-3016(82)90717-9. [DOI] [PubMed] [Google Scholar]
- Weichselbaum R. R., Little J. B. The differential response of human tumours to fractionated radiation may be due to a post-irradiation repair process. Br J Cancer. 1982 Oct;46(4):532–537. doi: 10.1038/bjc.1982.237. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Weichselbaum R. R., Nove J., Little J. B. Deficient recovery from potentially lethal radiation damage in ataxia telengiectasia and xeroderma pigmentosum. Nature. 1978 Jan 19;271(5642):261–262. doi: 10.1038/271261a0. [DOI] [PubMed] [Google Scholar]
- Zwelling L. A., Kerrigan D., Mattern M. R. Ataxia-telangiectasia cells are not uniformly deficient in poly(ADP-ribose) synthesis following X-irradiation. Mutat Res. 1983 Apr;120(1):69–78. doi: 10.1016/0165-7992(83)90076-3. [DOI] [PubMed] [Google Scholar]
