An Assay Method for the Prediction of Tumor Promoting Potential of Environmental Carcinogens Using 293 Cells

It has become important to develop a simple in vitro method for the detection of environmental carcinogen especially which could induce severe tumors. In order to detect suspected carcinogens and provide experimental evidence, we adopted 293 cell transformation systems to clarify the tumor promotive activity of microcystin LR (MC-LR) and benzo[a]pyrene (B[a]P) which were main carcinogens exist in drinking water and air respectively. We designed a method for detecting MC-LR and B[a]P by the use in vitro cell transformation system. In this method, 293 cells were cultured in flasks for 21 days during which test chemicals were added in the medium for 7 days, then the transformed 293 cells were tested by several methods including soft agar colony assay, serum requirement assay and tumorigenic activity to define the carcinogenetic activity. We found that when MC-LR was examined by the method, a reasonable correlation was observed with the reported tumor-promoting ability in animal experiments. We propose that the 293 cell transformation method was practical and useful for the detection of environmental carcinogens.