Application of the Improved BALB/c 3T3 Cell Transformation Assay to the Examination of the Initiating and Promoting Activities of Chemicals: The Second Inter-laboratory Collaborative Study by the Non-genotoxic Carcinogen Study Group of Japan

作者：Tsuchiya Toshiyuki^*; Umeda Makoto; Tanaka Noriho; Sakai Ayako; Nishiyama Hiroshi; Yoshimura Isao; Ajimi Syozo; Asada Shin; Asakura Masumi; Baba Hiroshi; Dewa Yasuaki; Ebe Youji; Fushiwaki Yuichi; Hagiwara Yuji; Hamada Shuichi; Hamamura Tetsuo; Iwase Yumiko; Kajiwara Yoshitsugu; Kasahara Yasushi; Kato Yukihiko; Kawabata Masayoshi; Kitada Emiko; Kaneko Kazuko; Kizaki Yuko; Kubo Kinya; Miura Daisaku; Mashiko Kaori; Mizuhashi Fukutaro; Muramatsu Dai; Nakajima Madoka

来源：ATLA-Alternatives to Laboratory Animals, 2010, 38(1): 11-27.

• BALB/c 3T3 cell transformation
• interlaboratory study
• one-stage assay
• two-stage assay

The Non-genotoxic Carcinogen Study Group in the Environmental Mutagen Society of Japan organised the second step of the inter-laboratory collaborative study on one-stage and two-stage cell transformation assays employing BALB/c 3T3 cells, with the objective of confirming whether the respective laboratories could independently produce results relevant to initiation or promotion. The method was modified to use a medium consisting of DMEM/F12 supplemented with 2% fetal bovine serum and a mixture of insulin, transferrin, ethanolamine and sodium selenite, at the stationary phase of cell growth. Seventeen laboratories collaborated in this study, and each chemical was tested by three to five laboratories. Comparison between the one-stage and two-stage assays revealed that the latter method would be beneficial in the screening of chemicals. In the test for initiating activity with the two-stage assay (post-treated with 0.1 mu g/ml 12-O-tetradecanoylphorbol-13-acetate), the relevant test laboratories all obtained positive results for benzo[a]pyrene and methylmethane sulphonate, and negative results for phenanthrene. Of those laboratories assigned phenacetin for the initiation phase, two returned positive results and two returned negative results, where the latter laboratories tested up to one dose lower than the maximum dose used by the former laboratories. In the exploration of promoting activity with the two-stage assay (pretreated with 0.2 mu g/ml 3-methylcholanthrene), the relevant test laboratories obtained positive results for mezerein, sodium orthovanadate and TGF-beta 1, and negative results for anthralin, phenacetin and phorbol. Two results returned for phorbol 12,13-didecanoate were positive, but one result was negative - again, the maximum dose to achieve the latter result was lower than that which produced the former results. These results suggest that this modified assay method is relevant, reproducible and transferable, provided that dosing issues, such as the determination of the maximum dose, are adequately considered. The application of this two-stage assay for screening the initiating and promoting potential of chemicals is recommended for consideration by other research groups and regulatory authorities.

• 出版日期2010-3