Canonical and Non-Canonical Functions of Histone H3K4 Methylation Modifiers in Cancer.

Histone H3K4 modifications are altered in the regulation of gene expression and in multiple cellular processes during cancer development and progression. Understanding the roles of H3K4-modifying enzymes will provide novel insights into therapeutic tools for cancer treatment. H3K4-modifying enzymes catalyze the addition or removal of covalent modifications with specific substrate preferences. Although these proteins are evolutionarily conserved between yeast and mammals, their protein domains and functions are not identical, and they exhibit signs of evolutionary divergence. Recent studies have indicated that H3K4-modifying enzymes play non-canonical roles via non-histone substrates or non-catalytic functions. Here, we discuss both canonical and non-canonical functions of H3K4-modifying enzymes and their potential benefits for therapeutic applications in cancer therapy.