Data from this and other laboratories indicate that the haloetyhl nitrosoureas react extensively with nucleic acids and that these reactions are responsible for the cytotoxic effects of these agents. This hypothesis has been strengthened by evidence that resistance of different cell lines to the nitrosoureas parallels their ability to repair DNA. The studies proposed here would attack the resistance problem by, first, identifying those specific DNA modifications which are responsible for cytotoxicity, emphasizing a search for crosslinked nucleosides since resistance has been associated with diminished DNA interstrand crosslinking. A crosslink between cytosine and guanine has recently been identified, and its mechanism of formation suggests that similar crosslinks may exist between adenine and thymine. Thus, a first objective will be to identify additional crosslinked nucleosides in DNA which has been reacted with the nitrosoureas in vitro. Then we will correlate the presence of these specific lesions with the sensitivity or resistance of various cell lines to the cytotoxic action of these agents. Lesions which are present in sensitive but absent in resistant cells would, by implication, be associated with cytotoxicity. Extracts of the resistant cell lines will be tested for their ability to remove crosslinked structures from DNA in vitro. Finally, this repair assay will be utilized to develop repair inhibitors which could restore sensitivity to the resistant cell lines.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA044499-02
Application #
3187128
Study Section
Experimental Therapeutics Subcommittee 2 (ET)
Project Start
1986-08-01
Project End
1990-07-31
Budget Start
1987-08-01
Budget End
1988-07-31
Support Year
2
Fiscal Year
1987
Total Cost
Indirect Cost
Name
University of Massachusetts Medical School Worcester
Department
Type
Schools of Medicine
DUNS #
660735098
City
Worcester
State
MA
Country
United States
Zip Code
01655
Li, Qiong; Wright, Stephen E; Matijasevic, Zdenka et al. (2003) The role of human alkyladenine glycosylase in cellular resistance to the chloroethylnitrosoureas. Carcinogenesis 24:589-93
Ludlum, D B; Li, Q; Matijasevic, Z (1999) Role of base excision repair in protecting cells from the toxicity of chloroethylnitrosoureas. IARC Sci Publ :271-7
Ludlum, D B (1997) The chloroethylnitrosoureas: sensitivity and resistance to cancer chemotherapy at the molecular level. Cancer Invest 15:588-98
Matijasevic, Z; Boosalis, M; Mackay, W et al. (1993) Protection against chloroethylnitrosourea cytotoxicity by eukaryotic 3-methyladenine DNA glycosylase. Proc Natl Acad Sci U S A 90:11855-9
Niu, T; Yu, D; Kirk, M C et al. (1993) Synthesis of the prototype DNA-protein cross-link, 1-(guan-1-yl)-2-(cysteine-S-yl)ethane, and its role in the reactions of the haloethylnitrosoureas. Carcinogenesis 14:195-8
Matijasevic, Z; Sekiguchi, M; Ludlum, D B (1992) Release of N2,3-ethenoguanine from chloroacetaldehyde-treated DNA by Escherichia coli 3-methyladenine DNA glycosylase II. Proc Natl Acad Sci U S A 89:9331-4
Ludlum, D B; Habraken, Y; Carter, C A et al. (1992) The formation and enzymatic repair of DNA modifications caused by the haloethylnitrosoureas and related compounds. Nucleic Acids Symp Ser :25-6
Gonzaga, P E; Potter, P M; Niu, T Q et al. (1992) Identification of the cross-link between human O6-methylguanine-DNA methyltransferase and chloroethylnitrosourea-treated DNA. Cancer Res 52:6052-8
Matijasevic, Z; Bodell, W J; Ludlum, D B (1991) 3-Methyladenine DNA glycosylase activity in a glial cell line sensitive to the haloethylnitrosoureas in comparison with a resistant cell line. Cancer Res 51:1568-70
Habraken, Y; Carter, C A; Kirk, M C et al. (1991) Release of 7-alkylguanines from N-(2-chloroethyl)-N'-cyclohexyl-N-nitrosourea-modified DNA by 3-methyladenine DNA glycosylase II. Cancer Res 51:499-503

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