Abstract
Equitoxic concentrations of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and methyl methanesulfonate (MeMes) produced different frequencies of 8-azaguanine-resistant mutants and different amounts of N7-methylguanine, O6-methylguanine (m6G), and N3-methyladenine in the DNA of V79 Chinese hamster cells. Thus, neither the cytotoxicities nor the mutagenicities of these methylating agents could be attributed solely to nitrogen or to oxygen methylations in the DNA. However, MNNG produced 12-fold more m6G and 5-fold more mutants than did MeMes, indicating that a substantial part of the MNNG-induced mutations resulted from m6G--thymine mispairing during DNA replication. The expression as mutants of mutagenic oxygen methylations in the DNA of cells treated with MNNG was enhanced by thymidine (dThd) and deoxycytidine (dCyd), but these nucleosides did not significantly enhance MeMes-induced mutagenesis. The cytotoxicities of MNNG and MeMes were also increased by 10 microM dThd in proportion to the amount of m6G in the DNA. These increases in cytotoxicity were abolished by dCyd, which did not greatly reduce the dThd-induced enhancements of mutagenesis. Moreover, when dThd was present only during the 2-hr treatment with MNNG, maximal cytotoxicity occurred, but MNNG-induced mutagenesis was not increased. Maximal mutagenesis occurred when the dThd was present throughout the first doubling time of the MNNG-treated cells. Thus, the expression of the cytotoxicity and the mutagenicity associated with m6G in the DNA of V79 cells occurred by quite different mechanisms.
Full text
PDF




Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Abbott P. J., Saffhill R. DNA synthesis with methylated poly(dC-dG) templates. Evidence for a competitive nature to miscoding by O(6)-methylguanine. Biochim Biophys Acta. 1979 Mar 28;562(1):51–61. doi: 10.1016/0005-2787(79)90125-4. [DOI] [PubMed] [Google Scholar]
- Bjursell G., Reichard P. Effects of thymidine on deoxyribonucleoside triphosphate pools and deoxyribonucleic acid synthesis in Chinese hamster ovary cells. J Biol Chem. 1973 Jun 10;248(11):3904–3909. [PubMed] [Google Scholar]
- Bradley M. O., Bhuyan B., Francis M. C., Langenbach R., Peterson A., Huberman E. Mutagenesis by chemical agents in V79 chinese hamster cells: a review and analysis of the literature. A report of the Gene-Tox Program. Mutat Res. 1981 Sep;87(2):81–142. doi: 10.1016/0165-1110(81)90029-4. [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]
- Farmer P. B., Foster A. B., Jarman M., Tisdale M. J. The alkylation of 2'-deoxyguanosine and of thymidine with diazoalkanes. Some observations on o-alkylation. Biochem J. 1973 Sep;135(1):203–213. doi: 10.1042/bj1350203. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fox M., Brennand J. Evidence for the involvement of lesions other than O6-alkylguanine in mammalian cell mutagenesis. Carcinogenesis. 1980 Sep;1(9):795–799. doi: 10.1093/carcin/1.9.795. [DOI] [PubMed] [Google Scholar]
- Friedman J., Huberman E. Postreplication repair and the susceptibility of Chinese hamster cells to cytotoxic and mutagenic effects of alkylating agents. Proc Natl Acad Sci U S A. 1980 Oct;77(10):6072–6076. doi: 10.1073/pnas.77.10.6072. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Goth-Goldstein R. Inability of Chinese hamster ovary cells to excise O6-alkylguanine. Cancer Res. 1980 Jul;40(7):2623–2624. [PubMed] [Google Scholar]
- Harris C. C. A delayed complication of cancer therapy--cancer. J Natl Cancer Inst. 1979 Aug;63(2):275–277. [PubMed] [Google Scholar]
- Lawley P. D., Thatcher C. J. Methylation of deoxyribonucleic acid in cultured mammalian cells by N-methyl-N'-nitro-N-nitrosoguanidine. The influence of cellular thiol concentrations on the extent of methylation and the 6-oxygen atom of guanine as a site of methylation. Biochem J. 1970 Feb;116(4):693–707. doi: 10.1042/bj1160693. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Meuth M. Role of deoxynucleoside triphosphate pools in the cytotoxic and mutagenic effects of DNA alkylating agents. Somatic Cell Genet. 1981 Jan;7(1):89–102. doi: 10.1007/BF01544750. [DOI] [PubMed] [Google Scholar]
- Newbold R. F., Warren W., Medcalf A. S., Amos J. Mutagenicity of carcinogenic methylating agents is associated with a specific DNA modification. Nature. 1980 Feb 7;283(5747):596–599. doi: 10.1038/283596a0. [DOI] [PubMed] [Google Scholar]
- Painter R. B. Effect of caffeine on DNA synthesis in irradiated and unirradiated mammalian cells. J Mol Biol. 1980 Nov 5;143(3):289–301. doi: 10.1016/0022-2836(80)90191-6. [DOI] [PubMed] [Google Scholar]
- Peterson A. R. DNA synthesis, mutagenesis, DNA damage, and cytotoxicity in cultured mammalian cells treated with alkylating agents. Cancer Res. 1980 Mar;40(3):682–688. [PubMed] [Google Scholar]
- Peterson A. R., Landolph J. R., Peterson H., Heidelberger C. Mutagenesis of Chinese hamster cells is facilitated by thymidine and deoxycytidine. Nature. 1978 Nov 30;276(5687):508–510. doi: 10.1038/276508a0. [DOI] [PubMed] [Google Scholar]
- Peterson A. R., Landolph J. R., Peterson H., Spears C. P., Heidelberger C. Oncogenic transformation and mutation of C3H/10T 1/2 clone 8 mouse embryo fibroblasts by alkylating agents. Cancer Res. 1981 Aug;41(8):3095–3099. [PubMed] [Google Scholar]
- Peterson A. R., Peterson H. Facilitation by pyrimidine deoxyribonucleosides and hypoxanthine of mutagenic and cytotoxic effects of monofunctional alkylating agents in Chinese hamster cells. Mutat Res. 1979 Jul;61(2):319–331. doi: 10.1016/0027-5107(79)90137-4. [DOI] [PubMed] [Google Scholar]
- Peterson A. R., Peterson H., Heidelberger C. Oncogenesis, mutagenesis, DNA damage, and cytotoxicity in cultured mammalian cells treated with alkylating agents. Cancer Res. 1979 Jan;39(1):131–138. [PubMed] [Google Scholar]
- Reichard P. From deoxynucleotides to DNA synthesis. Fed Proc. 1978 Jan;37(1):9–14. [PubMed] [Google Scholar]
- Roberts J. J., Pascoe J. M., Plant J. E., Sturrock J. E., Crathorn A. R. Quantitative aspects of the repair of alkylated DNA in cultured mammalian cells. I. The effect on HeLa and Chinese hamster cell survival of alkylation of cellular macromolecules. Chem Biol Interact. 1971 Feb;3(1):29–47. doi: 10.1016/0009-2797(71)90024-x. [DOI] [PubMed] [Google Scholar]
- Samson L., Schwartz J. L. Evidence for an adaptive DNA repair pathway in CHO and human skin fibroblast cell lines. Nature. 1980 Oct 30;287(5785):861–863. doi: 10.1038/287861a0. [DOI] [PubMed] [Google Scholar]
- Shearman C. W., Loeb L. A. Depurination decreases fidelity of DNA synthesis in vitro. Nature. 1977 Dec 8;270(5637):537–538. doi: 10.1038/270537a0. [DOI] [PubMed] [Google Scholar]
- Singer B. All oxygens in nucleic acids react with carcinogenic ethylating agents. Nature. 1976 Nov 25;264(5584):333–339. doi: 10.1038/264333a0. [DOI] [PubMed] [Google Scholar]
- Singer B. N-nitroso alkylating agents: formation and persistence of alkyl derivatives in mammalian nucleic acids as contributing factors in carcinogenesis. J Natl Cancer Inst. 1979 Jun;62(6):1329–1339. [PubMed] [Google Scholar]
- Singer B. The chemical effects of nucleic acid alkylation and their relation to mutagenesis and carcinogenesis. Prog Nucleic Acid Res Mol Biol. 1975;15(0):219–284. [PubMed] [Google Scholar]
- Suter W., Brennand J., McMillan S., Fox M. Relative mutagenicity of antineoplastic drugs and other alkylating agents in V79 Chinese hamster cells, independence of cytotoxic and mutagenic responses. Mutat Res. 1980 Nov;73(1):171–181. doi: 10.1016/0027-5107(80)90145-1. [DOI] [PubMed] [Google Scholar]
- Warren W., Crathorn A. R., Shooter K. V. The stability of methylated purines and of methylphosphotriesters in the DNA of V79 cells after treatment with N-methyl-N-nitrosourea. Biochim Biophys Acta. 1979 Jun 20;563(1):82–88. doi: 10.1016/0005-2787(79)90009-1. [DOI] [PubMed] [Google Scholar]
- de Saint Vincent B. R., Déchamps M., Buttin G. The modulation of the thymidine triphosphate pool of Chinese hamster cells by dCMP deaminase and UDP reductase. Thymidine auxotrophy induced by CTP in dCMP deaminase-deficient lines. J Biol Chem. 1980 Jan 10;255(1):162–167. [PubMed] [Google Scholar]
