An inter-laboratory collaborative study by the Non-Genotoxic Carcinogen Study Group in Japan, on a cell transformation assay for tumour promoters using Bhas 42 cells.
The Bhas promotion assay is a cell culture transformation assay designed as a sensitive and economical method for detecting the tumour-promoting activities of chemicals. In order to validate the transferability and applicability of this assay, an inter-laboratory collaborative study was conducted with the participation of 14 laboratories. After confirmation that these laboratories could obtain positive results with two tumour promoters, 12-O-tetradecanoylphorbol-13-acetate (TPA) and lithocholic acid (LCA), 12 coded chemicals were assayed. Each chemical was tested in four laboratories. For eight chemicals, all four laboratories obtained consistent results, and for two of the other four chemicals, only one of the four laboratories showed inconsistent results. Thus, the rate of consistency was high. During the study, several issues were raised, each of which were analysed step-by-step, leading to revision of the protocol of the original assay. Among these issues were the importance of careful maintenance of mother cultures and the adoption of test concentrations for toxic chemicals. In addition, it is suggested that three different types of chemicals show positive promoting activity in the assay. Those designated as T-type induced extreme growth enhancement, and included TPA, mezerein, PDD and insulin. LCA and okadaic acid belonged to the L-type category, in which transformed foci were induced at concentrations showing growth-inhibition. In contrast, M-type chemicals, progesterone, catechol and sodium saccharin, induced foci at concentrations with little or slight growth inhibition. The fact that different types of chemicals similarly induce transformed foci in the Bhas promotion assay may provide clues for elucidating mechanisms of tumour promotion.
Ohmori
Kiyomi
K
Chemistry Division, Kanagawa Prefectural Institute of Public Health, 1-3-1 Shimomachiya, Chigasaki, Kanagawa 253-0087, Japan. ohmori.n4yf@pref.kanagawa.jp
Umeda
Makoto
M
Tanaka
Noriho
N
Takagi
Hiroki
H
Yoshimura
Isao
I
Sasaki
Kiyoshi
K
Asasda
Shin
S
Sakai
Ayako
A
Araki
Harumi
H
Asakura
Masumi
M
Baba
Hiroshi
H
Fushiwaki
Yuichi
Y
Hamada
Shuichi
S
Kitou
Nobuko
N
Nakamura
Tetsu
T
Nakamura
Yoshiyuki
Y
Oishi
Hidetoshi
H
Sasaki
Satoshi
S
Shimada
Sawako
S
Tsuchiya
Toshiyuki
T
Uno
Yoshifumi
Y
Washizuka
Masataka
M
Yajima
Satoshi
S
Yamamoto
Yasuhito
Y
Yamamura
Eiji
E
Yatsushiro
Tomoko
T
D000826:Animal Testing Alternatives / Q000379:methods; D000818:Animals; D041702:BALB 3T3 Cells / Q000166:cytology / Q000187:drug effects*; D015197:Carcinogenicity Tests; D002273:Carcinogens / Q000032:analysis* / Q000633:toxicity*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002471:Cell Transformation, Neoplastic / Q000139:chemically induced*; D004305:Dose-Response Relationship, Drug; D007564:Japan; D008095:Lithocholic Acid / Q000494:pharmacology / Q000633:toxicity; D051379:Mice; D015203:Reproducibility of Results; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors
D002273:Carcinogens; D008095:Lithocholic Acid; D013755:Tetradecanoylphorbol Acetate