ChIP-seq Analysis to Explore DNA Replication Profile in Trifluridine-treated Human Colorectal Cancer Cells in Vitro

Background/ Aim: Trifluridine (FTD) is a key component of the novel oral antitumor drug trifluridine/tipiracil that has been approved for the treatment of metastatic colorectal cancer. In this study, a comprehensive analysis of DNA replication profile in FTD-treated colon cancer cells was performed. Materials and Methods: HCT-116 cells were exposed to BrdU or FTD and subjected to DNA immuno-precipitation. Immunoprecipitated DNA was sequenced; the density of aligned reads along the genome was calculated. Peak finding, gene ontology, and motif analysis were performed using MACS, GREAT, and MEME, respectively. Results: We identified 6,043 and 5,080 high-confidence FTD and BrdU peaks in HCT-116 cells, respectively. Of 6,043 FTD peaks, 2,911 peaks were uncommon to BrdU. We observed that FTD was preferentially incorporated into genomic regions containing simple repeats, CpG islands, and gene bodies. Conserved motifs in FTD peaks contained dinucleotide repeats such as (GT)n. Conclusion: Global FTD incorporation patterns delineated FTD, preferentially incorporating loci in cancer cells.