Oncotransformation in Bhas 42 Cell Transformation Assay by Typical Non-Genotoxic Carcinogens, PFOA and PFOS, and Time-Course Transcriptome Analysis

Perfluorinated alkyl substances and polyfluorinated alkyl substances (PFASs) are long-chain compounds, with perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) being the most well-known examples. Both are considered typical non-genotoxic carcinogens (NGTxCs). In this study, we verified whether the Bhas 42 cell transformation assay (Bhas 42 CTA) can be used as an effective in vitro method to predict carcinogenicity of NGTxCs using both PFOA and PFOS as typical representatives. Transcriptome analysis during the PFOA-induced transformation process showed that many factors related to the effects of PFOA on the immune system and cancer hallmarks increased or decreased. Thus, we demonstrated that mechanistic analyses such as transcriptome analyses in combination with the transformation focus formation results from the Bhas 42 CTA may be useful tools when assessing the carcinogenicity and other biological effects of NGTxCs such as PFOA. We propose that the Bhas 42 CTA is a simple in vitro test for the detection of NGTxCs, that it has in vitro oncotransformation as an endpoint, and that it can also detect the activation of factors involved in malignant progression, such as invasion and metastasis. It allows for the comprehensive detection of subtle mechanisms in parallel with focus formation throughout the transformation process, from the early stages to malignancy.