DNA methylation changes from primary cultures through senescence-bypass in Syrian hamster fetal cells initially exposed to benzo[a]pyrene

This SuperSeries is composed of the SubSeries listed below. Purpose: Historically, the Syrian Hamster Embryo - cell transformation assay (SHE-CTA) has provided a method to predict the carcinogenicity of test chemicals. Note that the cells harvested for the SHE-CTA are from fetuses at gestation day 13.5 and not from embryos as historically recorded. This method has been criticized for insufficient mechanistic understanding and subjective assessment of colonies morphological transformation. A more objective method is needed that additionally provides mode of action information. A possible mode of action of carcinogens includes disruption of DNA methylation in gene regulatory regions and consequent changes in gene expression. Such genetic loci could provide biomarkers to assist in predicting the carcinogenicity of both genotoxic and non-genotoxic chemicals acting through DNA methylation disruption. Refer to individual Series This series of experiments evaluates the use of reduced representation bisulfite sequencing and RNA-seq to discover biomarkers to predict carcinogenicity. Syrian Hamster fetal cells (SHF) were obtained using previously developed and validated methods [OECD, 2015. Guidance document on the in vitro Syrian hamster embryo (SHE) cell transformation assay. Series on Testing & Assessment No. 214, 1-24]. The protocol described by Pickles et. al (2016) was adapted to 1) treat SHF cells with (B[a]P) or vehicle control (DMSO), 2) collect morphologically transformed (MTc) and normal (Nc) colonies, and 3) to expand colony-derived cultures to senescence (SEN) and beyond (SENbp).