Discovery of α-mangostin as a novel competitive inhibitor against mutant isocitrate dehydrogenase-1.

Somatic heterozygous mutations of isocitrate dehydrogenase-1 (IDH1) are abundantly found in several types of cancer and strongly implicate altered metabolism in carcinogenesis. In the present study, we have identified α-mangostin as a novel selective inhibitor of mutant IDH1 (IDH1-R132H). We have observed that α-mangostin competitively inhibits the binding of α-ketoglutarate (α-KG) to IDH1-R132H. The structure-relationship study reveals that α-mangostin exhibits the strongest core inhibitor structure. Finally, we have observed that α-mangostin selectively promotes demethylation of 5-methylcytosine (5mC) and histone H3 trimethylated lysine residues in IDH1 (+/R132H) MCF10A cells, presumably via restoring the activity of cellular α-KG-dependent DNA hydroxylases and histone H3 lysine demethylases. Collectively, we provide evidence that α-mangostin selectively inhibits IDH1-R132H.