We plan to continue our efforts to elucidate the molecular mechanisms whereby certain selective antitumor antibiotic inhibitors of nucleic acid synthesis and function act. We expect that this work will not only contribute to our understanding of how anticancer drugs work, but will lead to the development of agents with greater selectivity for neoplastic cells and lowered toxicity for the host. An important by-product of such studies will be the development of new tools for the study of the biological processes involved in gene synthesis, expression and maintenance of integrity. We shall be concerned with the basis of action of members (neocarzinostatin and auromomycin) of a family of macromolecular (so-called protein antibiotics) antitumor antibiotics. In earlier work, we have established that these agents damage DNA by inducing single-strand breaks in intact mammalian cells and in cell-free systems. We have isolated labile, non-protein chromophores from these antibiotics which account for the biological properties of the holo-antibiotic. Details of the interaction between the chromophore, released from its apoprotein, and DNA will be investigated. In particular, the roles of oxygen and reducing agent in the DNA-damaging reaction and the structural changes in the chromophore involved in its activation will be studied. Evidence for covalent interaction between activated chromophore and DNA will be sought. The possible role of free radicals in the reaction will be clarified. In addition to studying details of the binding of chromophore to its natural carrier molecule, its specific apoprotein, other vehicular forms of the drug, that provide stability to the chromophore, will be investigated. Finally, the steps involved in the uptake of drug by mammalian cells and in the release of chromophore from the apoprotein carrier for its interation with cellular DNA will be elucidated.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM012573-21
Application #
3268382
Study Section
Physiological Chemistry Study Section (PC)
Project Start
1977-01-01
Project End
1986-12-31
Budget Start
1985-01-01
Budget End
1985-12-31
Support Year
21
Fiscal Year
1985
Total Cost
Indirect Cost
Name
Harvard University
Department
Type
Schools of Medicine
DUNS #
082359691
City
Boston
State
MA
Country
United States
Zip Code
Dedon, P C; Goldberg, I H (1992) Influence of thiol structure on neocarzinostatin activation and expression of DNA damage. Biochemistry 31:1909-17
Dedon, P C; Jiang, Z W; Goldberg, I H (1992) Neocarzinostatin-mediated DNA damage in a model AGT.ACT site: mechanistic studies of thiol-sensitive partitioning of C4' DNA damage products. Biochemistry 31:1917-27
Kappen, L S; Goldberg, I H; Frank, B L et al. (1991) Neocarzinostatin-induced hydrogen atom abstraction from C-4' and C-5' of the T residue at a d(GT) step in oligonucleotides: shuttling between deoxyribose attack sites based on isotope selection effects. Biochemistry 30:2034-42
Meschwitz, S M; Goldberg, I H (1991) Selective abstraction of 2H from C-5' of thymidylate in an oligodeoxynucleotide by the radical center at C-6 of the diradical species of neocarzinostatin: chemical evidence for the structure of the activated drug-DNA complex. Proc Natl Acad Sci U S A 88:3047-51
Galat, A; Goldberg, I H (1990) Molecular models of neocarzinostatin damage of DNA: analysis of sequence dependence in 5'GAGCG:5'CGCTC. Nucleic Acids Res 18:2093-9
Dedon, P C; Goldberg, I H (1990) Sequence-specific double-strand breakage of DNA by neocarzinostatin involves different chemical mechanisms within a staggered cleavage site. J Biol Chem 265:14713-6
Kappen, L S; Lee, T R; Yang, C C et al. (1989) Oxygen transfer from the nitro group of a nitroaromatic radiosensitizer to a DNA sugar damage product. Biochemistry 28:4540-2
Galat, A (1989) A procedure for analysis of densitometric spectra. Electrophoresis 10:659-67
Galat, A (1989) CORGEN: a FORTRAN-77 generator of standard and non-standard DNA helices from the sequence. Comput Appl Biosci 5:279-86
Hensens, O D; Goldberg, I H (1989) Mechanism of activation of the antitumor antibiotic neocarzinostatin by mercaptan and sodium borohydride. J Antibiot (Tokyo) 42:761-8

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