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 Google Scholar Google Scholar Articles by Nishigori, C. Articles by Takebe, H. Search for Related Content PubMed PubMed Citation Articles by Nishigori, C. Articles by Takebe, H.

Altered O⁶-Alkylguanine-DNA Alkyltransferase Activity in Cell Strains Originating from Mouse Skin Tumors Induced by UV Irradiation¹

Departments of Dematology, Shogoin Kawahara-cho [C. N., S-i. M.] and Experimental Radiology, Yoshida-konoecho [C. N., S-i. M., T. Y., H. T.], Faculty of Medicine, Kyoto University, Sakyo-ku, Kyoto 606, Japan

O⁶-Alkylguanine-DNA alkyltransferase (AGT) activity was assayed in the extracts of 47 cell strains originating from mouse skin tumors induced by UV irradiation. They were also examined for the sensitivity to 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride by colony formation. The AGT activity (fmol/mg protein) of the tumor cell strains varied widely and the mean ± SE was 72.5 ± 9.37, while the AGT activity of the nontumor cell strains was 134 ± 17. Among 47 strains, 6 strains showed extremely low or no AGT activity, about 5 fmol/mg protein or less, and were hypersensitive to 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride. Long-term culture of the tumor cells did not change the AGT activity except in some strains which might have had coexisting normal cells in the population in early passages. All strains showed similar UV sensitivity regardless of AGT activity. This is the first report which demonstrates that about 13% of newly induced tumor cell strains are deficient in AGT activity similar to Mer^-/Mex^- phenotype that was found in approximately 20% of the established human tumor cell strains.

¹ This work was supported by Grants-in-Aids from Ministry of Education, Science and Culture, Japan.

² To whom requests for reprints should be addressed, at Department of Experimental Radiology, Faculty of Medicine, Kyoto University, Yoshidakonoecho, Sakyo-ku, Kyoto 606, Japan.

Received 4/20/90. Accepted 2/22/91.