This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Minnick, D. T. Articles by David Sedwick, W. Search for Related Content PubMed PubMed Citation Articles by Minnick, D. T. Articles by David Sedwick, W.

Mutational Specificity of 1,3-Bis-(2-chloroethyl)-1-nitrosourea in a Chinese Hamster Ovary Cell Line¹

Departments of Environmental Health Sciences [D. T. M., M. L. V., W. D. S.] and Medicine [M. L. V., W. D. S.], Ireland Cancer Center, University Hospitals, Case Western Reserve University, Cleveland, Ohio 44106

The mutational specificity of the alkylating agent 1-3-bis-(2-chloroethyl)-1-nitrosourea (BCNU) was analyzed at the endogenous hemizygous adenine phosphoribosyl transferase gene of the Chinese hamster ovary cell line D422. A 1-h treatment of the Chinese hamster ovary cells with 50 µM BCNU resulted in a toxicity level of 62% and induced mutation at this target with a frequency of 32.1 mutants/10⁶ survivors (6-fold above background). Analysis of 49 BCNU-induced mutants at the DNA sequence level revealed that BCNU induced primarily base substitutions. The predominant BCNU-induced mutations were G:CT:A transversions, which comprised 51% (25 of 49) of the mutations; while G:CA:T transitions, expected from miscoding of O⁶-alkylguanine, represented only 16.3% (8 of 49) of the mutants recovered. This result was not anticipated, since Chinese hamster ovary cells are deficient in O⁶-alkylguanine-DNA alkyltransferase, which should render them especially sensitive to O⁶-alkylguanine-mediated mutations. It was also notable that two "hotspots" for BCNU-induced G:CT:A transversions were observed, which involved different surrounding DNA sequences but similar helix parameters when analyzed by an application of Calladine's Rules. Possible mechanisms for the observed BCNU-induced mutations are presented.

¹ Supported in part by National Institute of Environmental Health Services Research Grant R01 ESO5540 awarded to W. D. S.; a research grant from the Cuyahoga County Unit, Ohio Division of the American Cancer Society, awarded to M. L. V.; a research grant from Glaxo, Inc., to W. D. S. and M. L. V.; and a Cancer Center core grant to the Ireland Cancer Center (P30CA43703).

² To whom requests for reprints should be addressed, at Case Western Reserve University, Department of Medicine, Hematology/Oncology, UCRC Building 2, Suite 200, 11001 Cedar Road, Cleveland, OH 44106.

Received 2/17/92. Accepted 6/17/92.

This article has been cited by other articles:

				M. D. Bacolod, S. P. Johnson, A. E. Pegg, M. E. Dolan, R. C. Moschel, N. S. Bullock, Q. Fang, O. M. Colvin, P. Modrich, D. D. Bigner, et al. Brain tumor cell lines resistant to O6-benzylguanine/1,3-bis(2-chloroethyl)-1-nitrosourea chemotherapy have O6-alkylguanine-DNA alkyltransferase mutations Mol. Cancer Ther., September 1, 2004; 3(9): 1127 - 1135. [Abstract] [Full Text] [PDF]

				M. D. Bacolod, S. P. Johnson, F. Ali-Osman, P. Modrich, N. S. Bullock, O. M. Colvin, D. D. Bigner, and H. S. Friedman Mechanisms of Resistance to 1,3-Bis(2-chloroethyl)-1-nitrosourea in Human Medulloblastoma and Rhabdomyosarcoma Mol. Cancer Ther., July 1, 2002; 1(9): 727 - 736. [Abstract] [Full Text] [PDF]

				A. Inga, F.-X. Chen, P. Monti, A. Aprile, P. Campomenosi, P. Menichini, L. Ottaggio, S. Viaggi, A. Abbondandolo, B. Gold, et al. N-(2-Chloroethyl)-N-nitrosourea Tethered to Lexitropsin Induces Minor Groove Lesions at the p53 cDNA That Are More Cytotoxic than Mutagenic Cancer Res., February 1, 1999; 59(3): 689 - 695. [Abstract] [Full Text] [PDF]