Diallyl disulfide increases CDKN1A promoter-associated histone acetylation in human colon tumor cell lines

Diallyl disulfide (DADS) is an organosulfur compound from garlic, which inhibits colon tumor cell proliferation. In a previous study, we have shown that in Caco-2 and HT-29 cells DADS (200 AM) increases global histone acetylation, CDKN1A mRNA, and p21(waf1) protein levels and induces G(2)/M cell cycle arrest. These results suggested that DADS could inhibit cell proliferation through at least in part a transcriptional activation of CDKN1A expression involving histone acetylation. In this study, using chromatin immunoprecipitation assays, we demonstrate that in Caco-2 and HT-29 cells histone H4 and/or H3 acetylation is increased within CDKN1A promoter after 3 and 6 h treatments with DADS. These results strongly suggest that histone acetylation, a molecular mechanism implicated in the regulation of gene expression, could account for the induction of CDKN1A expression and the antiproliferating effects of DADS in colon tumor cells.