IDH1 R132H Mutation Enhances Cell Migration by Activating AKT-mTOR Signaling Pathway, but Sensitizes Cells to 5-FU Treatment as NADPH and GSH Are Reduced

Abstract

Aim of studyMutations of isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) gene were recently discovered in vast majority of World Health Organization (WHO) grade II/III gliomas. This study is to understand the effects of IDH1 R132H mutation in gliomagenesis and to develop new strategies to treat glioma with IDH1 R132H mutation.Materials and methodsOver expression of IDH1 R132H in U87MG cells was done by transfecting cells with IDH1 R132H plasmid. MTT assay, scratch repair assay and western blot were performed to study effects of IDH1 R132H mutation on cell proliferation, migration, regulating AKT-mTOR signaling pathway and cell death respectively. NADP+/NADPH and GSH quantification assays were performed to evaluate effects of IDH1 R132H mutation on the production of antioxidant NADPH and GSH.ResultsWe found that over expression of IDH1 R132H mutation decreased cell proliferation consistent with previous reports; however, it increased cell migration and enhanced AKT-mTOR signaling pathway activation. Mutations in isocitrate dehydrogenase (IDH) 1 also change the function of the enzymes and cause them to produce 2-hydroxyglutarate and not produce NADPH. We tested the level of NADPH and GSH and demonstrated that IDH1 R132H mutant stable cells had significantly low NADPH and GSH level compared to control or IDH1 wild type stable cells. The reduced antioxidants (NADPH and GSH) sensitized U87MG cells with IDH R132H mutant to 5-FU treatment.ConclusionOur study highlights the important role of IHD1 R132H mutant in up- regulating AKT-mTOR signaling pathway and enhancing cell migration. Furthermore, we demonstrate that IDH1 R132H mutation affects cellular redox status and sensitizes gliomas cells with IDH1 R132H mutation to 5FU treatment.

Rapamycin (mTORC1 inhibitor) reduces the production of lactate and 2-hydroxyglutarate oncometabolites in IDH1 mutant fibrosarcoma cells

“…This effect of rapamycin treatment highlights the importance of mTOR activity in malignant phenotype of IDH1 mutant cells. Our results – concerning the potential roles of mTOR activity and 2-HG production in migration of malignant cells – confirm the recently published data about the enhanced migration capacity of mIDH1 transfected glioma cells [45]. Only this study and our work show the potential benefit of mTOR inhibitors on the migration of IDH mutation related malignant cellular phenotype, in this context.…”

Successful treatment of spindle cell hemangiomas in a patient with Maffucci syndrome and review of literatures

“…Here, we report the first case of Maffucci syndrome associated SCH that was managed successfully using mTOR inhibitor as a concurrent medical therapy with surgery (Riou et al, 2012 Zhu et al (2017) has demonstrated that overexpression of mutated IDH1, increases cell migration and enhances AKT-mTOR signaling. These results support the use of mTOR inhibitor to target rapid vascular proliferation in Maffucci patients carrying IDH1 mutations.…”

“…Confirmatory diagnosis for that case could not be made as mutation of IDH gene was not detected. Recent in vitro study by Zhu et al () has demonstrated that overexpression of mutated IDH1 , increases cell migration and enhances AKT–mTOR signaling. These results support the use of mTOR inhibitor to target rapid vascular proliferation in Maffucci patients carrying IDH1 mutations.…”

Metabolic reprogramming in the pathogenesis of glioma: Update

“…IDH mutation sensitizes glioma cells to cytotoxic agents such as 5‐FU treatment through the reduction of antioxidants (NADPH and GSH) by mutant IDH , and to poly‐adenosine diphosphate ribose polymerase inhibition via inducing a mutant IDH ‐dependent homologous recombination defect (Fig. ) . From the metabolic viewpoint, mutant IDH1 lowered NAD + levels by downregulating the NAD + salvage pathway enzyme nicotinate phosphoribosyltransferase (NAPRT1), sensitizing to NAD + depletion via concomitant nicotinamide phosphoribosyltransferase (NAMPT) inhibition, identifying NAD + depletion as a metabolic susceptibility of IDH1 mutant cancers (Fig.…”

“…5). 60,61 From the metabolic viewpoint, mutant IDH1 lowered NAD + levels by downregulating the NAD + salvage pathway enzyme nicotinate phosphoribosyltransferase (NAPRT1), sensitizing to NAD + depletion via concomitant nicotinamide phosphoribosyltransferase (NAMPT) inhibition, identifying NAD + depletion as a metabolic susceptibility of IDH1 mutant cancers (Fig. 5).…”