Mutations in isocitrate dehydrogenase 2 accelerate glioma cell migration via matrix metalloproteinase-2 and 9

The gene encoding isocitrate dehydrogenase (IDH) is somatically mutated predominantly in secondary glioblastoma multiforme. Glioma-specific mutations in IDH1 always produced a single amino acid substitution at R132, but mutations in IDH2 were exclusively at R172 which was the analogous site to R132 in IDH1. Mutations of IDH1 and IDH2 led to simultaneous loss and gain of activities in the production of α-ketoglutarate and 2-hydroxyglutarate, respectively. Matrix metalloproteinases (MMPs) are zinc-dependent endoproteinases involved in the degradation of the extracellular matrix. The exact role of IDH2 mutant on MMPs activity and cell migration has not been fully studied. Here, we show that in response to IDH2 mutations, low levels of α-ketoglutarate increased the stabilization of HIF-1α which can contribute to tumor growth. Moreover, mutant IDH2-induced HIF-1α improved the secretion levels of pro-MMP-2 and pro-MMP-9 as well as the conversion from pro-MMP-2 to its active form, giving C6 glioma cells a higher migration potential. The HIF-1α pathway is probably a critical pathway for release of MMPs in the glioma cancer harboring IDH mutant.