Project description:p53 prevents tumor initiation and progression by adapting cell fate via transcriptional regulation of target gene networks. Here, we find that cancer associated mutations in isocitrate dehydrogenase (IDH) can uncouple p53 activity from tumor suppression by perturbing chromatin states that determine target gene expression. Mutant IDH impairs tumor regressions and promotes outgrowth of cancer cells with transcriptionally active, wild type p53 in a mouse model of liver cancer where restoration of p53 activity results in tumor clearance. Mutant IDH alters p53 target gene expression through the oncometabolite 2-hydroxyglutarate (2-HG), an inhibitor of alpha-ketoglutarate (KG) dependent chromatin remodeling enzymes, without preventing p53 accumulation or global genomic binding. Rather, mutant IDH alters chromatin accessibility landscapes that dictate target gene expression. Mutant IDH interferes with the expression of pro-apoptotic p53 targets, including the death ligand receptor Fas that enables p53 dependent liver tumor regressions. Pharmacological inhibition of mutant IDH in TP53 wildtype cholangiocarcinoma cells, a tumor type where p53 and IDH mutations are mutually exclusive, potentiates p53 target gene expression and sensitizes cells to Fas ligand and chemotherapy induced apoptosis. Therefore, we implicate disruption of p53 target gene regulation as a reversable, oncogenic feature of cancer associated IDH mutations.
Project description:p53 prevents tumor initiation and progression by adapting cell fate via transcriptional regulation of target gene networks. Here, we find that cancer associated mutations in isocitrate dehydrogenase (IDH) can uncouple p53 activity from tumor suppression by perturbing chromatin states that determine target gene expression. Mutant IDH impairs tumor regressions and promotes outgrowth of cancer cells with transcriptionally active, wild type p53 in a mouse model of liver cancer where restoration of p53 activity results in tumor clearance. Mutant IDH alters p53 target gene expression through the oncometabolite 2-hydroxyglutarate (2-HG), an inhibitor of alpha-ketoglutarate (KG) dependent chromatin remodeling enzymes, without preventing p53 accumulation or global genomic binding. Rather, mutant IDH alters chromatin accessibility landscapes that dictate target gene expression. Mutant IDH interferes with the expression of pro-apoptotic p53 targets, including the death ligand receptor Fas that enables p53 dependent liver tumor regressions. Pharmacological inhibition of mutant IDH in TP53 wildtype cholangiocarcinoma cells, a tumor type where p53 and IDH mutations are mutually exclusive, potentiates p53 target gene expression and sensitizes cells to Fas ligand and chemotherapy induced apoptosis. Therefore, we implicate disruption of p53 target gene regulation as a reversable, oncogenic feature of cancer associated IDH mutations.
Project description:Oligodendrogliomas are defined by IDH-mutations and codeletions of chromosomal arms 1p and 19q. In the past, case reports and small studies described gliomas with sarcomatous features arising from oligodendrogliomas, so called oligosarcomas. Here, we report a series of 23 IDH-mutant oligosarcomas forming a distinct methylation class. The tumors were recurrences from prior oligodendrogliomas or developed de novo. Precursor tumors of 11 oligosarcomas were histologically and molecularly indistinguishable from conventional oligodendrogliomas. Oligosarcoma tumor cells were embedded in a dens network of reticulin fibers, frequently showing p53 accumulation, positivity for SMA, and gain of H3K27 trimethylation (H3K27me3) as compared to primary lesions. In 5 oligosarcomas no 1p/19q codeletion was detectable, although it was present in the primary lesions. Oligosarcomas harbored an increased chromosomal copy number variation load with frequent CDKN2A/B deletions. Proteomic profiling demonstrated oligosarcomas to be highly distinct from conventional grade 3 oligodendrogliomas with consistent evidence for a smooth muscle differentiation. Expression of several tumor suppressors was reduced with NF1 being lost frequently. In contrast, oncogenic YAP1 was aberrantly overexpressed in oligosarcomas. Panel sequencing revealed mutations in NF1 and TP53 along with IDH1/2 and TERT promoter mutations. Survival of patients was significantly poorer for oligosarcomas than for grade 3 oligodendrogliomas and comparable to that of grade 4 IDH-mutant astrocytomas. These results establish oligosarcoma as a distinct type of IDH-mutant glioma differing from conventional oligodendrogliomas on the histologic, epigenetic, proteomic, molecular and clinical level. Diagnosis can be based on the characteristic DNA methylation profile or the combined evidence of sarcomatous histology, IDH-mutation and an oligodendroglioma-typical molecular alteration as TERT promoter mutation and/or 1p/19q codeletion.
Project description:Adult-type diffuse gliomas comprise IDH-mutant astrocytomas, IDH-mutant 1p/19q codeleted oligodendrogliomas (ODG), and IDH-wildtype glioblastomas (GBM). GBM display genome instability, which may result from two genetic events leading to massive chromosome alterations: chromothripsis (CT) and whole-genome duplication (WGD). The better prognosis of the latter may be related to their genome stability compared to GBM. Pangenomic profiles of 297 adult diffuse gliomas were analyzed at initial diagnosis using SNP arrays, including 192 GBM and 105 IDH-mutant gliomas (61 astrocytomas and 44 ODG). Tumor ploidy was assessed with Genome Alteration Print and CT events with CTLPScanner and through manual screening.
Project description:This multi-site, Phase 1/2 clinical trial is an open-label study to identify the safety, pharmacokinetics, and efficacy of a repeated dose regimen of NEO212 for the treatment of patients with radiographically-confirmed progression of Astrocytoma IDH-mutant, Glioblastoma IDH-wildtype, and the safety, pharmacokinetics and efficacy of a repeated dose regimen of NEO212 when given with select SOC for the treatment of solid tumor patients with radiographically confirmed uncontrolled brain metastasis. The study will have three phases, Phase 1, Phase 2a and Phase 2b.
Project description:RNA-sequencing for myeloid inflammation-related genes was conducted on primary tumor samples from patients with IDH-wildtype glioblastoma (GBM) and grade 4 IDH-mutant astrocytoma (G4IMA). In addition, the IDH-wildtype murine glioma cell line GL261 and a strain of IDH-mutant GL261 were also sequenced using the murine counterpart of the RNA-sequencing myeloid innate immunity panel.
Project description:Isocitrate dehydrogenase (IDH)-mutant gliomas have distinctive metabolic and biological traits that may render them susceptible to targeted treatments. Here, by conducting a high-throughput drug screen, we pinpointed a specific susceptibility of IDH-mutant gliomas to zotiraciclib (ZTR). ZTR exhibited selective growth inhibition across multiple IDH-mutant glioma in vitro and in vivo models. Mechanistically, ZTR at low doses suppressed CDK9 and RNA Pol II phosphorylation in IDH-mutant cells, disrupting mitochondrial function and NAD+ production, causing oxidative stress.,. Integrated biochemical profiling of ZTR kinase targets and transcriptomics unveiled that ZTR-induced bioenergetic failure was linked to the suppression of PIM kinase activity. We posit that the combination of mitochondrial dysfunction and an inability to adapt to oxidative stress resulted in significant cell death upon ZTR treatment, ultimately increasing the therapeutic vulnerability of IDH-mutant gliomas. These findings prompted a clinical trial evaluating ZTR in IDH-mutant gliomas towards precision medicine (NCT05588141).