Formation and Enzymatic Repair of Specific Reaction Products of Alkylating N-Nitroso Carcinogens in Cellular DNA: Relevance to Malignant Transformation

  • Manfred F. Rajewsky
  • Juergen Thomale
  • Nam-ho Huh
  • Peter Nehls
  • Gertrud Eberle
Chapter

Abstract

Structural modifications of genomic DNA, with the ensuing qualitative and quantitative alterations in the patterns of gene expression in the respective target cells and their progeny, appear to be key elements in the process of malignant transformation and tumorigenesis caused by cellular interactions with chemical carcinogens, radiation, or viruses. It is likely that the specific DNA sequence alterations (mutations) recently observed in genes associated with the tumorigenic conversion of various types of human and animal cells, may, at least in part, be traced back to the formation of specific adducts in genomic DNA by DNA-reactive agents from our environment.1,2 Of particular relevance with respect to the probability (“risk”) of carcinogen-induced malignant conversion of individual cells are (i) their capacity for enzymatic bioactivation of “precarcinogens” to their reactive derivatives (if such derivatives are not generated without enzymatic catalysis, i.e., by spontaneous decomposition of the parent compound),3 and (ii) their capacity for repair of damaged DNA in critical gene sequences via the action of specific repair enzymes.4 It goes without saying that the varying capacity of cells for enzymatic repair of specific DNA adducts also plays an important role with regard to cancer therapy, inasmuch as repair proficiency increases the resistance of cells towards the cytotoxic effects of DNA-reactive therapeutic agents.5 The present chapter focuses on N-nitroso compounds as an example of a large class of DNA-reactive alkylating carcinogens, using as a model a particularly potent carcinogen and mutagen, N-ethyl-N-nitrosourea (EtNU).4,6,7 Some aspects of the formation and distribution of the different alkylation products in genomic DNA will be discussed as well as the current methodology for their sensitive detection by monoclonal antibodies. Moreover, we will briefly describe results of experiments aiming at an evaluation of the relative importance of the selective enzymatic repair of one of these DNA alkylation products, O6-ethylguanine (O6-EtGua), as a determinant reducing the cellular risk of malignant transformation.

Keywords

Chemical Carcinogen 208F Cell Chromatin Fiber Alkylation Product Agar Coloni 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    S. Sukumar, V. Notario, D. Martin-Zanca, M. Barbacid, Induction of mammary carcinomas in rats by nitroso-methylurea involves malignant activation of H-ras-1 locus by single point mutations, Nature 306: 658 (1983).Google Scholar
  2. 2.
    C. I. Bargmann, M.-C. Hung, and R. A. Weinberg, Multiple independent activations of the neu oncogene by a point mutation altering the transmembrane domain of p185, Cell 45: 649 (1986).PubMedCrossRefGoogle Scholar
  3. 3.
    J. A. Miller and E. C. Miller, Perspectives on the metabolism of chemical carcinogens, in: “Environmental Carcinogenesis,” P. Emmelot and E. Krick, eds., Elsevier/North-Holland Biomedical Press, Amsterdam, p. 25 (1979).Google Scholar
  4. 4.
    M. F. Rajewsky, L. H. Augenlicht, H. Biessmann, R. Goth, D. F. Huelser, O. D. Laerum, and L. Ya. Lomakina, Nervous system-specific carcinogenesis by ethylnitrosourea in the rat: Molecular and cellular mechanisms, in: “Origins of Human Cancer,” Book B: “Mechanisms of Carcinogenesis,” H. H. Hiatt, J. D. Watson and J. A. Winsten, eds., Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y., p. 709 (1977).Google Scholar
  5. 5.
    M. F. Rajewsky and N. Huh, Molecular and cellular mechanisms underlying ineffective cancer chemotherapy, Recent Results in Cancer Res. 96: 18 (1984).CrossRefGoogle Scholar
  6. 6.
    R. Preussmann and B. W. Stewart, N-nitroso carcinogens, in: “Chemical Carcinogens,” 2nd ed., C. E. Searle, ed., ACS Monogr. 182, American Chemical Society, Washington, D.C., p. 643 (1984).Google Scholar
  7. 7.
    M. F. Rajewsky, Structural modifications and repair of DNA in neurooncogenesis by N-ethyl-N-nitrosourea, Recent Results in Cancer Res. 84: 63 (1983).Google Scholar
  8. 8.
    B. Singer and D. Grunberger, “Molecular Biology of Mutagens and Carcinogens,” Plenum Press, New York (1983).Google Scholar
  9. 9.
    M. F. Rajewsky, Chemical carcinogenesis in the developing nervous system, in: “Theories and Models in Cellular Transformation,” L. Zardi and L. Santi, eds., Academic Press, London, New York, p. 155 (1985).Google Scholar
  10. 10.
    B. Singer, W. J. Bodell, J. E. Cleaver, E. H. Thomas, M. F. Rajewsky, and W. Thon, Oxygens in DNA are main targets for ethylnitrosourea in normal and Xeroderma pigmentosum fibroblasts and fetal rat brain cells, Nature (Lond.) 276: 85 (1978).Google Scholar
  11. 11.
    M. F. Rajewsky, R. Mueller, J. Adamkiewicz, and W. Drosdziok, Immunological detection and quantification of DNA components structurally modified by alkylating carcinogensGoogle Scholar
  12. ethylnitrosourea), in: “Carcinogensis: Fundamental Mechanisms and Environmental Effects,” B. Pullman, P. 0. P. Ts’o, and H. Gelboin, eds., Reidel, Dordrecht, Boston, p. 207 (1980).Google Scholar
  13. 12.
    J. Adamkiewicz, W. Drosdziok, W. Eberhardt, U. Langenberg, and M. F. Rajewsky, High-affinity monoclonal antibodies specific for DNA components structurally modified by alkylating agents, in: “Indicators of Genotoxic Exposure,” B. A. Bridges, B. B. Butterworth, I. B. Weinstein, eds., Banbury Report 13, Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y., p. 265 (1982).Google Scholar
  14. J. Adamkiewicz, G. Eberle, N. Huh, P. Nehls, and M. F. Rajewsky, Quantitation and visualization of alkyl-deoxynucleosides in the DNA of mammalian cells by monoclonal antibodies, Environ. Health Persp. 62:49 (1985).Google Scholar
  15. 14.
    J. Adamkiewicz, 0. Ahrens, G. Eberle, P. Nehls, and M. F. Rajewsky, Monoclonal antibody-based immunoanalytical methods for detection of carcinogen-modified DNA components, in: “The Role of Cyclic Nucleic Acid Adducts in Carcinogenesis and Mutagenesis,” B. Singer and H. Bartsch, eds., IARC Scientific Publ. No. 70, Lyon, Internat. Agency for Research on Cancer, p. 403 (1986).Google Scholar
  16. 15.
    P. Nehls, M. F. Rajewsky, E. Spiess, and D. Werner, Highly sensitive sites for guanine-05 ethylation in rat brain DNA exposed to Nethyl-N-nitrosourea in vivo EMBO J. 3: 327 (1984).Google Scholar
  17. 16.
    V. A. Bohr, D. H. Phillips, and P. C. Hanawalt, Heterogeneous DNA damage and repair in the mammalian genome, Cancer Res. 47: 6426 (1987).Google Scholar
  18. 17.
    M. F. Rajewsky and P. Nehls, Structural and functional properties of genomic DNA contributing to the non-random formation and repair of carcinogen-DNA adducts, in: “Molecular Mechanisms of Carcinogenic and Antitumor Activity,” C. Chagas and B. Pullman, eds., Pontificiae Academiae Scientiarum Scripta Varia, Vol. 70, Vatican Press and Adenine Press, The Vatican, p. 131 (1987).Google Scholar
  19. 18.
    H. Weintraub and M. Groudine, Chromosomal subunits in active genes have an altered conformation, Science 193: 848 (1976).Google Scholar
  20. 19.
    P. Nehls and M. F. Rajewsky, Ethylation of nucleophilic sites in DNA by N-ethyl-N-nitrosourea depends on chromatin structure and ionic strength, Mutation Res. 150: 13 (1985).Google Scholar
  21. 20.
    P. Nehls and M. F. Rajewsky, Differential formation of 06-ethylguanine in the DNA of chromatin fibers of different folding levels exposed to N-ethyl-N-nitrosourea in vitro, Cancer Res. 45: 1378 (1985).Google Scholar
  22. 21.
    R. Cox, Differences in the removal of N-methyl-N-nitrosoureamethylated products in DNase I-sensitive and -resistant regions of rat brain DNA, Cancer Res. 39: 2675 (1979).Google Scholar
  23. 22.
    P. Nehls and M. F. Rajewsky, Ethylation of fetal rat brain chromosomal DNA by ethylnitrosourea, Proc. Sect. Exp. Cancer Res. German Cancer Soc., J. Cancer Res. Clin. Oncol. 99: A38 (1981).Google Scholar
  24. 23.
    T. R. Irvin and G. N. Wogan, Quantitation of aflatoxin B1 adduction within the ribosomal RNA gene sequences of rat liver DNA, Proc. Natl. Acad. Sci. USA 81: 664 (1984).CrossRefGoogle Scholar
  25. 24.
    J. Doniger, R. S. Day, and J. A. DiPaolo, Quantitative assessment of the role of 06-methylguanine in the initiation of carcinogenesis by methylating agents, Proc. Natl. Acad. Sci. USA 82: 421 (1985).PubMedCrossRefGoogle Scholar
  26. 25.
    J. Thomale, N. Huh, and M. F. Rajewsky, Risk of tumorigenic conversion of 208F rat cells exposed to N-ethyl-N-nitrosourea (EtNU): Inverse correlation with cellular capacity for enzymatic removal of 06ethylguanine from DNA, Proc. Sect. Exp. Cancer Res. German Cancer Soc., J. Cancer Res. Clin. Oncol. 113: 22 (1987).Google Scholar

Copyright information

© Springer Science+Business Media New York 1989

Authors and Affiliations

  • Manfred F. Rajewsky
    • 1
  • Juergen Thomale
    • 1
  • Nam-ho Huh
    • 1
  • Peter Nehls
    • 1
  • Gertrud Eberle
    • 1
  1. 1.Institut fuer Zellbiologie (Tumorforschung)Universitaet Essen (GH)Essen 1Federal Republic of Germany

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