Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.1.1.41 (isocitrate dehydrogenase)
 3,101 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Angioimmunoblastic T-cell lymphoma (AITL) is a common subtype of peripheral T-cell lymphoma (PTCL) with a poor prognosis. We performed targeted resequencing on 92 cases of PTCL and identified frequent mutations affecting RHOA, TET2, DNMT3A, and isocitrate dehydrogenase 2 (IDH2). Although IDH2 mutations are largely confined to AITL, mutations of the other 3 can be found in other types of PTCL, although at lower frequencies. These findings indicate a key role of epigenetic regulation in the pathogenesis of AITL. However, the epigenetic alterations induced by these mutations and their role in AITL pathogenesis are still largely unknown. We correlated mutational status with gene expression and global DNA methylation changes in AITL. Strikingly, AITL cases with IDH2(R172) mutations demonstrated a distinct gene expression signature characterized by downregulation of genes associated with TH1 differentiation (eg, STAT1 and IFNG) and a striking enrichment of an interleukin 12-induced gene signature. Ectopic expression of IDH2(R172K) in the Jurkat cell line and CD4(+) T cells led to markedly increased levels of 2-hydroxyglutarate, histone-3 lysine methylation, and 5-methylcytosine and a decrease of 5-hydroxymethylcytosine. Correspondingly, clinical samples with IDH2 mutations displayed a prominent increase in H3K27me3 and DNA hypermethylation of gene promoters. Integrative analysis of gene expression and promoter methylation revealed recurrently hypermethylated genes involved in T-cell receptor signaling and T-cell differentiation that likely contribute to lymphomagenesis in AITL.
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PMID:IDH2R172 mutations define a unique subgroup of patients with angioimmunoblastic T-cell lymphoma. 2645 Sep 50

Oncogenic isocitrate dehydrogenase (IDH)1 and IDH2 mutations at three hotspot arginine residues cause an enzymatic gain of function that leads to the production and accumulation of the metabolite 2-hydroxyglutarate (2HG), which contributes to the development of a number of malignancies. In the hematopoietic system, mutations in IDH1 at arginine (R) 132 and in IDH2 at R140 and R172 are commonly observed in acute myeloid leukemia, and elevated 2HG is observed in cells and serum. However, in angioimmunoblastic T-cell lymphoma (AITL), mutations are almost exclusively restricted to IDH2 R172, and levels of 2HG have not been comprehensively measured. In this study, we investigate the expression pattern of mutant IDH2 in the AITL tumor microenvironment and measure levels of 2HG in tissue and serum of AITL patients. We find that mutant IDH2 expression is restricted to the malignant T-cell component of AITL, and that 2HG is elevated in tumor tissue and serum of patients. We also investigate the differences between the three hotspot mutation sites in IDH1 and IDH2 using conditional knock-in mouse models. These studies show that in the lymphoid system, mutations in IDH2 at R172 produce high levels of 2HG compared with mutations at the other two sites and that lymphoid development is impaired in these animals. These data provide evidence that IDH2 R172 mutations may be the only variants present in AITL because of their capacity to produce significant amounts of the oncometabolite 2HG in the cell of origin of this disease.
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PMID:The IDH2 R172K mutation associated with angioimmunoblastic T-cell lymphoma produces 2HG in T cells and impacts lymphoid development. 2795 31

Recent genetic analysis has identified frequent mutations in ten-eleven translocation 2 (TET2), DNA methyltransferase 3A (DNMT3A), isocitrate dehydrogenase 2 (IDH2) and ras homolog family member A (RHOA) in nodal T-cell lymphomas, including angioimmunoblastic T-cell lymphoma and peripheral T-cell lymphoma, not otherwise specified. We examined the distribution of mutations in these subtypes of mature T-/natural killer cell neoplasms to determine their clonal architecture. Targeted sequencing was performed for 71 genes in tumor-derived DNA of 87 cases. The mutations were then analyzed in a programmed death-1 (PD1)-positive population enriched with tumor cells and CD20-positive B cells purified by laser microdissection from 19 cases. TET2 and DNMT3A mutations were identified in both the PD1+ cells and the CD20+ cells in 15/16 and 4/7 cases, respectively. All the RHOA and IDH2 mutations were confined to the PD1+ cells, indicating that some, including RHOA and IDH2 mutations, being specific events in tumor cells. Notably, we found that all NOTCH1 mutations were detected only in the CD20+ cells. In conclusion, we identified both B- as well as T-cell-specific mutations, and mutations common to both T and B cells. These findings indicate the expansion of a clone after multistep and multilineal acquisition of gene mutations.
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PMID:Identification of cell-type-specific mutations in nodal T-cell lymphomas. 2815 89

Angioimmunoblastic T-cell lymphoma (AITL) is an age-related malignant lymphoma, characterized by immune system-dysregulated symptoms. Recent sequencing studies have clarified the recurrent mutations in ras homology family member A (RHOA) and in genes encoding epigenetic regulators, tet methyl cytosine dioxygenase 2 (TET2), DNA methyl transferase 3 alpha (DNMT3A) and isocitrate dehydrogenase 2, mitochondrial (IDH2), as well as those related to the T-cell receptor signaling pathway in AITL. In this review, we focus on how this genetic information has changed the understanding of the developmental process of AITL and will in future lead to individualized therapies for AITL patients.
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PMID:Review of the biologic and clinical significance of genetic mutations in angioimmunoblastic T-cell lymphoma. 2888 81

Angioimmunoblastic T-cell lymphoma (AITL) is a peripheral T-cell lymphoma associated with chemoresistance and a poor prognosis. Various nonsynonymous mutations in the R172 residue of IDH2 are present in 20% to 30% of AITL patients. In addition to their diagnostic value, these mutations are potentially targetable, especially by isocitrate dehydrogenase (IDH) 2 inhibitor, and therefore their identification in a routine setting is clinically relevant. However, in AITL, the neoplastic cells may be scarce, making the identification of molecular anomalies difficult. We evaluated the diagnostic value of different methods to detect IDH2 mutations in formalin-fixed, paraffin-embedded tumor samples. Immunohistochemistry with an anti-IDH2 R172K antibody, Sanger sequencing, high-resolution melting PCR, allele-specific real-time quantitative PCR, and next-generation sequencing (NGS) were applied to biopsy specimens from 42 AITL patients. We demonstrate that the IDH2 R172K antibody is specific to this amino acid substitution and highly sensitive for the detection of the IDH2R172K variant, the most frequent substitution in this disease. In our study, NGS and allele-specific real-time quantitative PCR displayed a good sensitivity, detecting 96% and 92% of IDH2 mutations, respectively, in contrast to Sanger sequencing and high-resolution melting PCR, which showed a significantly lower detection rate (58% and 42%, respectively). These results suggest that a combination of immunohistochemistry and AS-PCR or NGS should be considered for the identification of IDH2 mutations in AITL in a routine setting.
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PMID:Multiple Ways to Detect IDH2 Mutations in Angioimmunoblastic T-Cell Lymphoma from Immunohistochemistry to Next-Generation Sequencing. 2998 67