title: Bhas 42 cell transformation activity of cigarette smoke condensate is modulated by selenium and arsenic.
abstract: Cigarette smoking remains a major health risk worldwide. Development of newer tobacco products requires the use of quantitative toxicological assays. Recently, v-Ha-ras transfected BALB/c3T3 (Bhas 42) cell transformation assay was established that simulates the two-stage animal tumorigenesis model and measures tumor initiating and promoting activities of chemicals. The present study was performed to assess the feasibility of using this Bhas 42 cell transformation assay to determine the initiation and promotion activities of cigarette smoke condensate (CSC) and its water soluble fraction. Further, the modulating effects of selenium and arsenic on cigarette smoke-induced cell transformation were investigated. Dimethyl sulfoxide (DMSO) and water extracts of CSC (CSC-D and CSC-W, respectively) were tested at concentrations of 2.5-40 µg mL(-1) in the initiation or promotion assay formats. Initiation protocol of the Bhas 42 assay showed a 3.5-fold increase in transformed foci at 40 µg mL(-1) of CSC-D but not CSC-W. The promotion phase of the assay yielded a robust dose response with CSC-D (2.5-40 µg mL(-1)) and CSC-W (20-40 µg mL(-1)). Preincubation of cells with selenium (100 nM) significantly reduced CSC-induced increase in cell transformation in initiation assay. Co-treatment of cells with a sub-toxic dose of arsenic significantly enhanced cell transformation activity of CSC-D in promotion assay. The results suggest a presence of both water soluble and insoluble tumor promoters in CSC, a role of oxidative stress in CSC-induced cell transformation, and usefulness of Bhas 42 cell transformation assay in comparing tobacco product toxicities and in studying the mechanisms of tobacco carcinogenesis.
authors.affiliation: Toxicology Laboratory, Department of Food Science and Biotechnology of Animal Resources, College of Animal Bioscience and Technology, Konkuk University, Seoul, 05029, Republic of Korea.
authors.forename: Sung Gu
authors.initials: SG
authors.lastname: Han
authors.affiliation: Department of Genetic Toxicology, Bioreliance Corporation, Rockville, Maryland.
authors.forename: Kamala
authors.initials: K
authors.lastname: Pant
authors.affiliation: Department of Genetic Toxicology, Bioreliance Corporation, Rockville, Maryland.
authors.forename: Shannon W
authors.initials: SW
authors.lastname: Bruce
authors.affiliation: Department of Genetic Toxicology, Graduate Center for Toxicology, College of Medicine, University of Kentucky, Lexington, Kentucky.
authors.forename: C Gary
authors.initials: CG
authors.lastname: Gairola
mesh_terms: D000818:Animals; D001151:Arsenic / Q000633:toxicity*; D015197:Carcinogenicity Tests / Q000379:methods; D002461:Cell Line, Transformed / Q000187:drug effects*; D002471:Cell Transformation, Neoplastic / Q000187:drug effects; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D051379:Mice; D012643:Selenium / Q000633:toxicity*; D012907:Smoking / Q000009:adverse effects*; D018675:Toxicity Tests / Q000379:methods*
chemical_list: D012643:Selenium; D001151:Arsenic; D004121:Dimethyl Sulfoxide
keywords: Bhas 42 cells; arsenic; cell transformation; cigarette smoke condensate; selenium; tumorigenesis