Project description:Histone deacetylases (HDACs) have a wide range of targets and can rewire both the chromatin and lipidome of cancer cells. In this study, we show that valproic acid (VPA), a brain penetrant anti-epilepticseizure medication and histone deacetylase inhibitor, inhibits the growth of IDH1 mutant tumors in vivo and in vitro, with at least some selectivity over IDH1 wild-type tumors. Surprisingly, genes upregulated by VPA showed no change inenhanced chromatin accessibility at the promoter, but there was a correlation between VPA-downregulated genes and diminished promoter chromatin accessibility. VPA inhibited the transcription of lipogenic genes and these lipogenic genes showed significant decreases in promoter chromatin accessibility only in the IDH1 MT glioma cell lines tested. VPA inhibited the mTOR pathway and a key lipogenic gene, fatty acid synthase (FASN). Both VPA and a selective FASN inhibitor TVB-2640 rewired the lipidome and promoted apoptosis in an IDH1 MT but not in an IDH1 WT glioma cell line. We further find that HDACs are involved in the regulation of lipogenic genes and HDAC6 is particularly important for the regulation of FASN in IDH1 MT glioma. Finally, we show that FASN knockdown alone and VPA in combination with FASN knockdown significantly improved the survival of mice in an IDH1 MT primary orthotopic xenograft model in vivo. We conclude that targeting fatty acid metabolism through HDAC inhibition and/or FASN inhibition may be a novel therapeutic opportunity in IDH1 mutant gliomas.
Project description:Histone deacetylases (HDACs) have a wide range of targets and can rewire both the chromatin and lipidome of cancer cells. In this study, we show that valproic acid (VPA), a brain penetrant anti-epilepticseizure medication and histone deacetylase inhibitor, inhibits the growth of IDH1 mutant tumors in vivo and in vitro, with at least some selectivity over IDH1 wild-type tumors. Surprisingly, genes upregulated by VPA showed no change inenhanced chromatin accessibility at the promoter, but there was a correlation between VPA-downregulated genes and diminished promoter chromatin accessibility. VPA inhibited the transcription of lipogenic genes and these lipogenic genes showed significant decreases in promoter chromatin accessibility only in the IDH1 MT glioma cell lines tested. VPA inhibited the mTOR pathway and a key lipogenic gene, fatty acid synthase (FASN). Both VPA and a selective FASN inhibitor TVB-2640 rewired the lipidome and promoted apoptosis in an IDH1 MT but not in an IDH1 WT glioma cell line. We further find that HDACs are involved in the regulation of lipogenic genes and HDAC6 is particularly important for the regulation of FASN in IDH1 MT glioma. Finally, we show that FASN knockdown alone and VPA in combination with FASN knockdown significantly improved the survival of mice in an IDH1 MT primary orthotopic xenograft model in vivo. We conclude that targeting fatty acid metabolism through HDAC inhibition and/or FASN inhibition may be a novel therapeutic opportunity in IDH1 mutant gliomas.
Project description:Astrocytoma, oligodendroglioma, oligoastrocytoma, and ependymoma are the main histologic subtypes of glioma. The molecular character of these subtypes has profound implications for understanding their causes and treatment. We describe the epigenetic landscape of these tumor types using novel DNA methylation profiling tools. There is a robust association of methylation profile with tumor histology and IDH1 mutation status. Furthermore, tumors with IDH1 mutation independently predict a tumor hypermethylator phenotype, histology, TP53 mutation status, patient age, and survival. Integrating tumor epigenetic and genetic alterations, this work provides a critical step toward better defining the somatic nature of glioma which will have great potential to impact clinical approaches to disease. This work provides an important step forward in classification of malignant brain tumors using DNA methylation profiling, integrating knowledge regarding IDH1 mutation in gliomas. The epigenetic homogeneity of the IDH1 mutant subclass despite histologic diversity implies that IDH1 mutation is a “driver” or functional determinant of a distinct DNA methylation phenotype, suggesting a novel role for an altered metabolic profile in the brain. This association occurs across histologic subtypes and demonstrates a clear relationship between genetic alteration and epigenetic profile. Fresh frozen tumor tissues were obtained from the University of California San Francisco (UCSF) Brain Tumor Research Center tissue bank with appropriate institutional review board approval. Tumors were diagnosed between 1990 and 2003. Tumor samples were defined as secondary GBM if the patients had prior histological diagnosis of a low-grade glioma. Tumors had previously been reviewed by UCSF neuropathologists to assign histologic subtype and grade. Normal brain tissue samples were from cancer-free patients who underwent temporal lobe resection as treatment for epilepsy at UCSF.
Project description:Astrocytoma, oligodendroglioma, oligoastrocytoma, and ependymoma are the main histologic subtypes of glioma. The molecular character of these subtypes has profound implications for understanding their causes and treatment. We describe the epigenetic landscape of these tumor types using novel DNA methylation profiling tools. There is a robust association of methylation profile with tumor histology and IDH1 mutation status. Furthermore, tumors with IDH1 mutation independently predict a tumor hypermethylator phenotype, histology, TP53 mutation status, patient age, and survival. Integrating tumor epigenetic and genetic alterations, this work provides a critical step toward better defining the somatic nature of glioma which will have great potential to impact clinical approaches to disease. This work provides an important step forward in classification of malignant brain tumors using DNA methylation profiling, integrating knowledge regarding IDH1 mutation in gliomas. The epigenetic homogeneity of the IDH1 mutant subclass despite histologic diversity implies that IDH1 mutation is a “driver” or functional determinant of a distinct DNA methylation phenotype, suggesting a novel role for an altered metabolic profile in the brain. This association occurs across histologic subtypes and demonstrates a clear relationship between genetic alteration and epigenetic profile.
Project description:The aim of ths study is to compare global methylation status between 1) IDH1 mutant and IDH1/2 wild-type glioblastoma tumorsphere cells and 2) MGG152 (IDH1 mutant) with DMSO and IDH1 inhibitor treatment. Genome wide DNA methylation profiling of patient derived glioblastoma tumorsphere and HT1080 cells. The Illumina Infinium Human DNA methylation Beadchip450 was used to obtain DNA methylation profiles. Bisulphite converted DNA from the 10 samples and one control were hybridised to the Illumina Infinium Human Methylation Beadchip450. Please note that the MGG (in the sample title) represents patient-derived MGH glioblastoma cell lines. Regarding MGG152 samples, sample no.1 is low passage number and used for comparison between IDH1 mt and wild-type. Sample no. 2-4 were used for assessing DNA methylation change after short term or long term IDH1 inhibiting treatment.