title: Induction of neoplastic transformation and DNA single-strand breaks in C3H/10T1/2 clone 8 cells by polycyclic hydrocarbons and alkylating agents.
abstract: The standard C3H/10T1/2 clone 8 (C3H/10T1/2 CL8) cell transformation assay was tested for its ability to identify a variety of polycyclic hydrocarbons and alkylating agents. Dose-dependent morphologic transformation occurred with benzo[a]pyrene (BaP), 3-methylcholanthrene (MCA), 7,12-dimethylbenz[a]anthracene, BaP-7,8-dihydroxy-7,8-dihydrodiol (BaP-7,8-diol), as well as with the relatively weak in vivo carcinogen benzo[e]pyrene. Dibenz[a,h]anthracene yielded a relatively weak response, whereas anthracene and phenanthrene were negative. In contrast, treatment of C3H/10T1/2 CL8 cells with two directly acting alkylating agents, N-nitroso-N-methylnitroguanidine (MNNG) and styrene oxide, gave no transformation, whereas a third alkylating agent, ethyl methanesulfonate (EMS), gave a weak response. Treatment with MCA (2.5 micrograms/ml) yielded a reproducible positive response and, therefore, served as a positive control for routine use of the C3H/10T1/2 CL8 assay. When cells treated with the hydrocarbons BaP, BaP-7,8-diol, or MCA were analyzed for nonspecific DNA damage (single-strand breaks or alkaline-labile sites) by alkaline elution techniques, little if any DNA damage was observed. In contrast, the alkylating agents MNNG, styrene oxide, and EMS yielded substantial numbers of single-strand breaks.
mesh_terms: D000477:Alkylating Agents / Q000633:toxicity*; D000818:Animals; D001564:Benzo(a)pyrene; D001580:Benzopyrenes / Q000633:toxicity; D002470:Cell Survival / Q000187:drug effects*; D002471:Cell Transformation, Neoplastic / Q000139:chemically induced*; D002999:Clone Cells; D004260:DNA Repair; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D005020:Ethyl Methanesulfonate / Q000633:toxicity; D008748:Methylcholanthrene / Q000633:toxicity; D008769:Methylnitronitrosoguanidine / Q000633:toxicity; D051379:Mice; D011083:Polycyclic Compounds / Q000633:toxicity*
chemical_list: D000477:Alkylating Agents; D001580:Benzopyrenes; D011083:Polycyclic Compounds; D008769:Methylnitronitrosoguanidine; D001564:Benzo(a)pyrene; D008748:Methylcholanthrene; C026487:benzo(e)pyrene; D005020:Ethyl Methanesulfonate