title: Interlaboratory studies with the Chinese hamster V79 cell metabolic cooperation assay to detect tumor-promoting agents.
abstract: Three laboratories participated in an interlaboratory study to evaluate the usefulness of the Chinese hamster V79 cell metabolic cooperation assay to predict the tumor-promoting activity of selected chemicals. Twenty-three chemicals of different chemical structures (phorbol esters, barbiturates, phenols, artificial sweeteners, alkanes, and peroxides) were chosen for testing based on in vivo promotion activities, as reported in the literature. Assay protocols and materials were standardized, and the chemicals were coded to facilitate unbiased evaluation. A chemical was tested only once in each laboratory, with one of the three laboratories testing only 15 out of 23 chemicals. Dunnett's test was used for statistical analysis, and differences between treated- and control-cell responses were analyzed at P less than or equal to .01. Chemicals were scored as positive (at least two concentration levels statistically different than control), equivocal (only one concentration statistically different), or negative. For 15 chemicals tested in all three laboratories, there was complete agreement among the laboratories for nine chemicals. For the 23 chemicals tested in only two laboratories, there was agreement on 16 chemicals. With the exception of the peroxides and alkanes, the metabolic cooperation data were in general agreement with in vivo data. However, an overall evaluation of the V79 cell system for predicting in vivo promotion activity was difficult because of the organ specificity of certain chemicals and/or the limited number of adequately tested nonpromoting chemicals.
authors.affiliation: Centers for Disease Control, Division of Biomedical and Behavioral Science, Cincinnati, OH 45226.
authors.forename: J S
authors.initials: JS
authors.lastname: Bohrman
authors.forename: J R
authors.initials: JR
authors.lastname: Burg
authors.forename: E
authors.initials: E
authors.lastname: Elmore
authors.forename: D K
authors.initials: DK
authors.lastname: Gulati
authors.forename: T R
authors.initials: TR
authors.lastname: Barkfnecht
authors.forename: R W
authors.initials: RW
authors.lastname: Niemeier
authors.forename: B L
authors.initials: BL
authors.lastname: Dames
authors.forename: M
authors.initials: M
authors.lastname: Toraason
authors.forename: R
authors.initials: R
authors.lastname: Langenbach
mesh_terms: D000818:Animals; D002273:Carcinogens / Q000145:classification / Q000494:pharmacology*; D002450:Cell Communication / Q000187:drug effects*; D002471:Cell Transformation, Neoplastic / Q000139:chemically induced*; D003114:Colony-Forming Units Assay; D006224:Cricetinae; D003412:Cricetulus; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism; D007365:Intercellular Junctions / Q000187:drug effects; D008168:Lung; D008297:Male; D011237:Predictive Value of Tests; D013866:Thioguanine / Q000378:metabolism
chemical_list: D002273:Carcinogens; D013866:Thioguanine