Chronology of DNA methylation changes through transformation stage leading to senescence by-pass in Syrian hamster fetal primary cells exposed to benzo[a]pyrene

Purpose: To use reduced representaion bisulfite sequencing to measure differential genome methylation among: 1. cells treated with benzo[a]pyrene (B[a]P) versus vehicle alone (DMSO) using the Syrian Hamster Cell Transformation Assay method; 2. cells originating from normal (Nc) versus morphologically transformed (MTc) colonies; 3. cells in senescence (SEN) versus those that have bypassed senescence (SENbp). Reduced representation bisulfite sequencing was performed to measure cytosine methylation within genomic DNA. Four biological replicates were sampled to study B[a]P versus untreated colonies (DMSO) and MT versus N colonies. Four technical replicates were sampled to study senescence versus senescence-bypass. All cells were confirmed male using a rapid XY qPCR assay.