Targeting epigenetic mechanisms: potential of natural products in cancer chemoprevention.

The term epigenetics is defined as heritable changes in gene expression patterns that occur without changes in DNA sequence. Epigenetic changes according to this definition are achieved by methylation of cytosine bases in the DNA and by histone modifications, such as acetylation, methylation or phosphorylation. These modifications play an important role in regulating gene expression and the existence of an epigenetic code which maintains these modifications even upon cell division has been underlined by many investigations. Targeting the enzymes which catalyze DNA methylation or histone modifications may be a possibility not only for cancer therapy but also for chemoprevention since disruption of epigenetic balance is known to cause diseases such as cancer. In this review, we want to present the key epigenetic targets. We highlight natural products that modulate these epigenetic mechanisms and show their potential for cancer chemoprevention.