A high-throughput Bhas 42 cell transformation assay for the determination of the carcinogenicity of three herbal extracts

Abstract

The Bhas 42 cell transformation assay is a sensitive and effective mutation assay, and it has been widely used to detect and evaluate potential carcinogenic risks, including initiation assay and promotion assay. In this transformation assay, the number of transformed foci is the only criterion. However, it is nonquantitative because the shape is irregular. Nevertheless, a high-throughput Bhas 42 cell transformation assay was developed, which includes the usage of hydrogen peroxide in 96-well plates. In this way, transformed foci are quantitatively analysed in proportion to the optical density value (OD value). In this study, the Bhas 42 cell transformation assay was established using the criterion of the OD value. As a result, 3-methylcholanthrene (3-MCA) presented strong tumour initiation activity, whereas the 12-O-tetradecanoylphorbol-13-acetate (TPA) showed strong tumour promotion activity. Lowdaphne Stringbush Flower and Leaf (LSFL, also named as Wikstroemia chamaedaphne (Bunge) Meissn) and Rhubarb (Rheum palmatum L.) showed strong tumour promotion activity, but the tumour promotion activity of Lilac Daphne Flower Bud (LDFB, also named as Daphne genkwa Siebold & Zucc) was equivocal. Surprisingly, the OD value displayed a strong correlation with the number of transformed foci. In conclusion, the high-throughput Bhas 42 cell transformation assay was feasible.