Targeting Histone Modifications in Colorectal Cancer: Therapeutic Potential of Epigenetic Modifiers on Acetylation, Methylation and Phosphorylation

Colorectal cancer (CRC), like all other cancers, results from genetic and epigenetic alterations of the genome. The mechanisms leading to epigenetic alterations include DNA methylation, histone modifications, and small non-coding RNAs. As shown in many studies, some histone modifications such as acetylation, methylation, and phosphorylation are reported to be altered in CRC. Since these epigenetic alterations are reversible, they can be targeted as a strategy for CRC treatment. Numerous studies demonstrate the effects of molecules (both natural and synthetic) as inhibitors of enzymes responsible for histone acetylation, methylation, and phosphorylation in CRC cell lines. Some of these molecules have reached clinical trial stages. Vorinostat and belinostat, as histone deacetylase inhibitors; pinometostat and ribavirin, as histone methyltransferase inhibitors; and staurosporine and barasertib, which target histone phosphorylation, are among the promising epigenetic modifiers targeting histone alterations. Some of these modifiers can be used alone or in combination with other anticancer drugs or radiotherapy to increase efficacy. This review aims to identify molecules that target enzymes responsible for altering acetylation, methylation, and phosphorylation of histones in CRC.