Changes on histone H3 modifications on the GLUT5 gene and its expression in Caco-2 cells co-treated with a p44/42 MAPK inhibitor and glucocorticoid hormone.

Changes on histone H3 modifications from methylation at lysine 9 to acetylation at lysine 9/14 is thought to be important for transcriptional activation of genes associated with differentiation. In this study, we found that the treatment with a p44/42 MAPK inhibitor, PD98059, induced di-methylation at lysine 9 on the upstream/transcriptional regions of the GLUT5 gene. Co-treatment of PD98059 with a glucocorticoid hormone agonist, dexamethasone (Dex), not only repressed the induction of di-methylation by PD98059, but also enhanced the acetylation of histone H3 at lysine 9/14 on the GLUT5 gene, as well as its gene expression. These results suggest that the histone H3 di-methylation at lysine 9, as well as acetylation at lysine 9/14, may be indispensable for coordinated induction of the GLUT5 gene by p44/42 MAP kinase inhibition and the glucocorticoid hormone.