Abstract |
Chloroethylnitrosoureas (CNUs) are being used in the therapy of various neoplastic diseases, including skin cancer. Because secondary tumor formation is a serious threat in chemotherapy with these drugs, we explored whether and to what extent the DNA repair protein DNA-O6-methylguanine: protein- L-cysteine S- methyltransferase (MGMT) protects against CNU-induced tumors. We made use of transgenic mice overexpressing human MGMT in their skin and the initiation-promotion protocol on treatment with 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea ( ACNU, nimustine) that is representative of CNUs. ACNU applied topically as a single low dose to the dorsal skin was highly effective in tumor induction in nontransgenic mice, whereas in cytokeratin MGMT transgenic mice, tumor formation was remarkably reduced. ACNU-induced skin tumors harbored mutations in the c-Ha-ras gene in both groups of mice. The results provide clear evidence that MGMT exerts protection against CNU-induced cancer. Our data also indicate that O6-chloroethylguanine, which is repaired by MGMT, is a main precarcinogenic CNU-induced DNA lesion.
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Authors | K Becker, C M Gregel, B Kaina |
Journal | Cancer research
(Cancer Res)
Vol. 57
Issue 16
Pg. 3335-8
(Aug 15 1997)
ISSN: 0008-5472 [Print] United States |
PMID | 9269990
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Antineoplastic Agents, Alkylating
- Nimustine
- Methyltransferases
- O(6)-Methylguanine-DNA Methyltransferase
- Tetradecanoylphorbol Acetate
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Topics |
- Animals
- Antineoplastic Agents, Alkylating
(adverse effects)
- DNA Mutational Analysis
- Genes, ras
(drug effects, genetics)
- Humans
- Methyltransferases
(physiology)
- Mice
- Mice, Transgenic
- Neoplasms, Experimental
(chemically induced, enzymology, genetics, prevention & control)
- Nimustine
(adverse effects)
- O(6)-Methylguanine-DNA Methyltransferase
- Papilloma
(chemically induced, enzymology, genetics, prevention & control)
- Point Mutation
- Skin Neoplasms
(chemically induced, enzymology, genetics, prevention & control)
- Tetradecanoylphorbol Acetate
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