A genome-wide study of DNA methylation modified by epigallocatechin-3-gallate in the CAL-27 cell line.

In order to gain greater understanding of the mechanisms underlying the effect of epigallocatechin-3-gallate (EGCG) on DNA methylation and its chemopreventative action in oral squamous cell carcinoma (OSCC), a genome‑wide methylation and mRNA expression screen was performed in the CAL‑27 cell line with and without EGCG (100 µM) treatment. A total of 761 differentially methylated gene loci were identified following treatment with EGCG. Comparison of gene expression profiling in OSCC samples revealed 184 transcripts with a significant difference (P<0.05) and a fold change difference >2 compared with controls. Gene ontology analysis of differentially methylated loci and functional annotation of the differentially expressed genes indicated that the main pathways involved were metabolic, mitogen‑activated protein kinase (MAPK), wnt, and cell cycle pathways. In conclusion, the present study indicates that EGCG can affect the methylation status and gene expression in the CAL‑27 cell line. Additionally, the changes in several important signaling pathways may reveal the antitumor mechanism of EGCG.