Histone deacetylases as targets for dietary cancer preventive agents: Lessons learned with butyrate, diallyl disulfide, and sulforaphane

Cancer is a multi-factorial process involving genetic and epigenetic events which result in neoplastic transformation. Reversal of aberrant epigenetic events, including those that modulate the transcriptional activity of genes associated with various signaling pathways, holds the prospect of influencing multiple stages of tumorigenesis. Perturbation of normal historic acetylation status can result in undesirable phenotypic changes, including developmental disorders and cancer. Indeed, aberrant historic acetylation may be ail etiological factor in several, if not all, types of cancer. In general, histone acetylation leads to chromatin remodeling and a de-repression of transcription. Historic deacetylase (HDAC) inhibitors may be useful for cancer prevention and therapy by virtue of their ability to 'reactivate' the expression of epigenetically silenced genes, including those involved in differentiation, cell cycle regulation, apoptosis, angiogenesis, invasion, and metastasis. Several natural and synthetic HDAC inhibitors have been shown to affect the growth and survival of tumor cells in vitro and in vivo. Interestingly, three dietary chemopreventive agents, butyrate, diallyl disulfide, and sulforaphane, also have HDAC inhibitory activity. This review discusses the role of aberrant historic acetylation in tumorigenesis and describes the potential for cancer chemoprevention and therapy with a particular emphasis oil dietary HDAC inhibitors.