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Methylation profiling of enchondromas with and without IDH1 mutations

ABSTRACT: Ollier disease and Maffucci syndrome are non-hereditary skeletal disorderscharacterized by multiple enchondromas (Ollier disease) combined with spindle cellhemangiomas (Maffucci syndrome). Somatic heterozygous IDH1 (R132C and R132H) orIDH2 (R172S) mutations were found in 87% of enchondromas, benign cartilage tumors,as well as in 70% of spindle cell hemangiomas, benign vascular lesions. In total, 35 of 43(81%) patients with Ollier disease and 10 of 13 (77%) patients with Maffucci syndromecarried IDH1 (98%) or rarely IDH2 (2%) mutations in their tumors. Fourteen patientswith multiple tumors at different anatomic locations displayed identical mutations inseparate lesions. Since in other tumor types the presence of an IDH1 mutation is strongly associated withhypermethylation 26, 27, we assessed whether there was a difference in methylation patternof enchondromas with (n = 8) and without (n = 4) IDH1 mutations detactable at Sangersequencing. Methylation and expressionprofiling showed that IDH1 mutations in cartilage tumors are associated withhypermethylation and downregulation of the expression of several genes.

ORGANISM(S): Homo sapiens

PROVIDER: GSE31337 | GEO | 2011/11/05

SECONDARY ACCESSION(S): PRJNA154167

REPOSITORIES: GEO

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Project description:Ollier disease and Maffucci syndrome are non-hereditary skeletal disorderscharacterized by multiple enchondromas (Ollier disease) combined with spindle cellhemangiomas (Maffucci syndrome). Somatic heterozygous IDH1 (R132C and R132H) orIDH2 (R172S) mutations were found in 87% of enchondromas, benign cartilage tumors,as well as in 70% of spindle cell hemangiomas, benign vascular lesions. In total, 35 of 43(81%) patients with Ollier disease and 10 of 13 (77%) patients with Maffucci syndromecarried IDH1 (98%) or rarely IDH2 (2%) mutations in their tumors. Fourteen patientswith multiple tumors at different anatomic locations displayed identical mutations inseparate lesions. Since in other tumor types the presence of an IDH1 mutation is strongly associated withhypermethylation 26, 27, we assessed whether there was a difference in methylation patternof enchondromas with (n = 8) and without (n = 4) IDH1 mutations detactable at Sangersequencing. Methylation and expressionprofiling showed that IDH1 mutations in cartilage tumors are associated withhypermethylation and downregulation of the expression of several genes. Total 12 samples which includes 8 enchondromas with IDH1 mutation (4 Ollier enchondromas, 2 Maffucci enchondromas and 2 solitary enchondromas) and 4 enchondromas (1 Ollier enchondroma, 3 solitary enchondromas) without IDH1 or IDH2 mutations were used. Of these 4 enchondromas without IDH1 mutation, one had R132G IDH1 mutated cells present in the subpopulation, below the threshold level of Sanger sequencing. Bisulfite treatment was performed using EZ DNA Methylation™ Kit (ZymoResearch, Orange, CA). Bisulphite converted DNA was then hybridized to IlluminaHumanMethylation27 BeadChip (Illumina Inc., San Diego, CA) by followingmanufacturer’s instructions. Infinium Unsupervised clustering analysis was performed 25 using the Ward’s clustering algorithm based on Euclidian distance. The 2000 most variable CpG sites (excluding those on the X and Y chromosomes) were used in the clustering analysis.

Project description:Gene expression of mouse hepatoblasts (HBs) expressing IDH1 WT, IDH1 R132C, IDH2 WT, R172K and empty vector controls (N=2 cultures for each condition) grown on collagen-coated plates and IDH1 R132C and empty vector controls on uncoated plates were evaluated using Affymetrix Mouse 430Av2 DNA microarrays that were processed at the Dana-Farber Cancer Institute core facility (http://macf-web.dfci.harvard.edu/) using their standard protocol. Mutations in Isocitrate dehydrogenase 1 (IDH1) and IDH2 are among the most common genetic alterations in intrahepatic cholangiocarcinoma (IHCC), a deadly primary liver cancer. Mutant IDH proteins in IHCC and other malignancies acquire an abnormal enzymatic activity allowing them to convert alphaketoglutarate (aKG) to 2-hydroxyglutarate (2HG), which inhibits the activity of multiple aKG-dependent dioxygenases, and results in alterations in cell differentiation, survival, and extracellular matrix maturation. However, the molecular pathways by which IDH mutations lead to tumour formation remain unclear. Here we show that mutant IDH blocks primary liver progenitor cells from undergoing hepatocyte differentiation through the production of 2HG and suppression of HNF4a, a master regulator of hepatocyte identity and quiescence. Correspondingly, genetically engineered mouse models (GEMMs) expressing mutant IDH in the adult liver show aberrant response to hepatic injury, characterized by HNF4a silencing, impaired hepatocyte differentiation and markedly elevated levels of cell proliferation. Moreover, mutant IDH and activated Kras, genetic alterations that co-exist in a subset of human IHCCs, cooperate to drive the expansion of liver progenitor cells, development of premalignant biliary lesions, and progression to metastatic IHCC. These studies provide a functional link between IDH mutations, hepatic cell fate, and IHCC pathogenesis and present a novel GEMM of IDH-driven malignancy. Gene expression of HBs expressing IDH1 WT, IDH1 R132C, IDH2 WT, R172K and empty vector controls under a doxycycline-inducible system (N=2 cultures for each condition) grown on collagen-coated plates and IDH1 R132C and empty vector controls on uncoated plates were evaluated using Affymetrix Mouse 430Av2 DNA microarrays.

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Methylation profiling of enchondromas with and without IDH1 mutations

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