IDH2
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Spinal deformities such as scoliosis and kyphosis are incurable, and can lead to decreased physical function, pain, and reduced quality of life. Despite much effort, no clear therapies for the treatment of these conditions have been found. Therefore, the development of an animal model for spinal deformity would be extremely valuable to our understanding of vertebral diseases. In this study, we demonstrate that mice deficient in the mitochondrial enzyme isocitrate dehydrogenase 2 (IDH2) develop spinal deformities with aging. We use morphological analysis as well as radiographic and micro-CT imaging of IDH2-deficient mice to characterize these deformities. Histological analysis showed increased abnormalities in IDH2-deficient mice compared to wild type mice. Taken together, the results suggest that IDH2 plays a critical role in maintaining the spinal structure by affecting the homeostatic balance between osteoclasts and osteoblasts. This indicates that IDH2 might be a potent target for the development of therapies for spinal deformities. Our findings also provide a novel animal model for vertebral disease research.
- MeSH
- isocitrátdehydrogenasa genetika MeSH
- modely nemocí na zvířatech * MeSH
- myši knockoutované MeSH
- nemoci páteře diagnostické zobrazování etiologie patologie MeSH
- páteř patologie MeSH
- rentgenová mikrotomografie MeSH
- stárnutí patologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Mitochondrial NADPH-dependent isocitrate dehydrogenase, IDH2, and cytosolic IDH1, catalyze reductive carboxylation of 2-oxoglutarate. Both idh2 and idh1 monoallelic mutations are harbored in grade 2/3 gliomas, secondary glioblastomas and acute myeloid leukemia. Mutant IDH1/IDH2 enzymes were reported to form an oncometabolite r-2-hydroxyglutarate (2HG), further strengthening malignancy. We quantified CO2-dependent reductive carboxylation glutaminolysis (RCG) and CO2-independent 2HG production in HTB-126 and MDA-MB-231 breast carcinoma cells by measuring (13)C incorporation from 1-(13)C-glutamine into citrate, malate, and 2HG. For HTB-126 cells, (13)C-citrate, (13)C-malate, and (13)C-2-hydroxyglutarate were enriched by 2-, 5-, and 15-fold at 5mM glucose (2-, 2.5-, and 13-fold at 25 mM glucose), respectively, after 6 h. Such enrichment decreased by 6% with IDH1 silencing, but by 30-50% upon IDH2 silencing while cell respiration and ATP levels rose up to 150%. Unlike 2HG production RCG declined at decreasing CO2. At hypoxia (5% O2), IDH2-related and unrelated (13)C-accumulation into citrate and malate increased 1.5-2.5-fold with unchanged IDH2 expression; whereas hypoxic 2HG formation did not. (13)C-2HG originated by ∼50% from other than IDH2 or IDH1 reactions, substantiating remaining activity in IDH1&2-silenced cells. Relatively high basal (12)C-2HG levels existed (5-fold higher vs. non-tumor HTB-125 cells) and (13)C-2HG was formed despite the absence of any idh2 and idh1 mutations in HTB-126 cells. Since RCG is enhanced at hypoxia (frequent in solid tumors) and 2HG can be formed without idh1/2 mutations, we suggest 2HG as an analytic marker (in serum, urine, or biopsies) predicting malignancy of breast cancer in all patients.
- MeSH
- glutaráty metabolismus MeSH
- hypoxie buňky fyziologie MeSH
- isocitrátdehydrogenasa genetika metabolismus MeSH
- kyslík metabolismus MeSH
- lidé MeSH
- nádorové biomarkery genetika metabolismus MeSH
- nádorové buněčné linie MeSH
- nádory prsu enzymologie genetika metabolismus MeSH
- parciální tlak MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Wild type mitochondrial isocitrate dehydrogenase (IDH2) was previously reported to produce oncometabolite 2-hydroxyglutarate (2HG). Besides, mitochondrial deacetylase SIRT3 has been shown to regulate the oxidative function of IDH2. However, regulation of 2HG formation by SIRT3-mediated deacetylation was not investigated yet. We aimed to study mitochondrial IDH2 function in response to acetylation and deacetylation, and focus specifically on 2HG production by IDH2. We used acetylation surrogate mutant of IDH2 K413Q and assayed enzyme kinetics of oxidative decarboxylation of isocitrate, 2HG production by the enzyme, and 2HG production in cells. The purified IDH2 K413Q exhibited lower oxidative reaction rates than IDH2 WT. 2HG production by IDH2 K413Q was largely diminished at the enzymatic and cellular level, and knockdown of SIRT3 also inhibited 2HG production by IDH2. Contrary, the expression of putative mitochondrial acetylase GCN5L likely does not target IDH2. Using mass spectroscopy, we further identified lysine residues within IDH2, which are the substrates of SIRT3. In summary, we demonstrate that 2HG levels arise from non-mutant IDH2 reductive function and decrease with increasing acetylation level. The newly identified lysine residues might apply in regulation of IDH2 function in response to metabolic perturbations occurring in cancer cells, such as glucose-free conditions.
- MeSH
- acetylace MeSH
- glutaráty metabolismus MeSH
- isocitrátdehydrogenasa genetika metabolismus MeSH
- isocitráty chemie MeSH
- lidé MeSH
- mitochondrie metabolismus MeSH
- nádorové buněčné linie MeSH
- NADP metabolismus MeSH
- oxidace-redukce MeSH
- proteiny nervové tkáně metabolismus MeSH
- sirtuin 3 metabolismus MeSH
- umlčování genů MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Mitochondrial production of 2-hydroxyglutarate (2HG) can be catalyzed by wild-type isocitrate dehydrogenase 2 (IDH2) and alcohol dehydrogenase, iron-containing 1 (ADHFE1). We investigated whether biochemical background and substrate concentration in breast cancer cells promote 2HG production. To estimate its role in 2HG production, we quantified 2HG levels and its enantiomers in breast cancer cells using analytical approaches for metabolomics. By manipulation of mitochondrial substrate fluxes using genetic and pharmacological approaches, we demonstrated the existence of active competition between 2HG producing enzymes, i.e., IDH2 and ADHFE1. Moreover, we showed that distinct fractions of IDH2 enzyme molecules operate in distinct oxido-reductive modes, providing NADPH and producing 2HG simultaneously. We have also detected 2HG release in the urine of breast cancer patients undergoing adjuvant therapy and detected a correlation with stages of breast carcinoma development. In summary, we provide a background for vital mitochondrial production of 2HG in breast cancer cells with outcomes towards cancer biology and possible future diagnosis of breast carcinoma.
- Publikační typ
- časopisecké články MeSH
- Klíčová slova
- ivosidenib, azacitidine,
- MeSH
- akutní myeloidní leukemie * diagnóza farmakoterapie genetika MeSH
- diagnostické techniky molekulární metody MeSH
- genetické testování MeSH
- inhibitory enzymů farmakologie terapeutické užití MeSH
- lidé MeSH
- protokoly protinádorové kombinované chemoterapie MeSH
- randomizované kontrolované studie jako téma MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
OBJECTIVES: Molecular screening plays a major role in prognostic categorization and subsequent definition of treatment strategies for acute myeloid leukemia. The possibility of using IDH1/2 mutations as a marker for the monitoring of minimal residual disease (MRD) is still under investigation and remains unclear. METHODS: In this retrospective study, we evaluated 90 patients with de novo AML using Sanger sequencing (exon 4, IDH1 and IDH2). For subsequent MRD monitoring were used both methods, massive parallel sequencing and droplet digital PCR (ddPCR). RESULTS: We identified 22 patients (24%) who harboured mutations in IDH1 or IDH2 genes. Fourteen (64%) of them had other commonly used MRD markers (insertion in NPM1 and partial tandem duplication of MLL, MLL-PTD). Eight of the 22 patients had IDH1 mutations, 13 had IDH2 mutations and 1 had both IDH1 and IDH2 mutations. In our cohort, this IDH1/2 marker responded to the treatment in all of the patients and reflected the onset of the relapse very well. NPM1 mutation based MRD monitoring was more sensitive and predicted relapse earlier but IDH1/2 based monitoring was more sensitive than a method based on MLL-PTD. Both massive parallel sequencing and ddPCR were competent to monitor MRD using IDH1/2. Nevertheless, ddPCR was able to achieve a higher sensitivity in some cases and moreover this method can analyse a single sample without significant price increases. CONCLUSION: Given these data, we conclude that IDH1/2 mutations can be used as a reliable and cost-effective marker for MRD monitoring.
- MeSH
- akutní myeloidní leukemie diagnóza enzymologie genetika terapie MeSH
- dospělí MeSH
- exony MeSH
- genetická predispozice k nemoci * MeSH
- genetické asociační studie MeSH
- indukce remise MeSH
- isocitrátdehydrogenasa chemie genetika metabolismus MeSH
- kohortové studie MeSH
- lidé středního věku MeSH
- lidé MeSH
- mutace * MeSH
- mutační analýza DNA MeSH
- následné studie MeSH
- nemocnice univerzitní MeSH
- prognóza MeSH
- retrospektivní studie MeSH
- reziduální nádor MeSH
- senioři MeSH
- substituce aminokyselin MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
