Project description:WHO classification for tumors of the central nervous system strongly endorses molecular tests for the precise diagnosis of diffuse gliomas. While alterations in the DNA methylation status of gliomas are already well documented and used in specialised clinical centers to distinguish between brain tumor entities, changes to the epigenetic layer at the level of histone modifications are only poorly characterised. Here, we applied a recently developed data-independent acquisition (DIA) - mass spectrometry method to generate a comprehensive histone epi-proteomic map that documents the abundance of almost all characterized and many uncharacterized histone modifications to a series of IDH-mutant oligodendroglioma and astrocytoma samples. Our analysis documented significant abundance differences in almost one-third of the 144 quantified histone peptides. Among them are lower abundance levels of the polycomb repressive mark H3K27me3 in oligodendroglioma samples compared to astrocytomas. We validated this finding by immunohistochemistry using the C36B11 antibody. Surprisingly, we observed inconsistencies with another widely applied H3K27me3 antibody (07-449), providing a warning flag for immunohistochemistry of brain cancers. An unbiased unsupervised clustering analysis of the proteomic dataset separated the two IDH-mutant glioma subtypes in full accordance to the EPIC DNA methylation classifier and the 1p/19q status. The clustering also revealed at least two histone epi-proteomic subgroups of oligodendroglioma, a feature not observable in the DNA methylation dataset. Our results indicate that histone epi-proteomic profiling at the depth of the current method has the capacity to identify clinically-relevant glioma sub-groups. In addition to being of use for diagnostic purposes, this could also provide novel insights in glioma biology and may identify new therapeutic targets.
Project description:Oligoastrocytoma (OA) was formerly defined as a mixed glioma exhibiting histological features of both astrocytoma and oligodendroglioma. However, OA has been shown to be attributable to either glioma-type based on its molecular characteristics and was excluded from the glioma classification with the introduction of the integrated diagnosis. Nevertheless, some cases showing genetic features of both oligodendroglioma and astrocytoma have been reported since the integrated diagnosis era, and whether OA exists as a glioma-type remains controversial. All previously reported cases were mixed gliomas with and without 1p/19q-codeletion in the lineage of isocitrate dehydrogenase (IDH) mutant gliomas. Herein, we described a 33-year-old man with a progressive headache. Magnetic resonance imaging showed a large left frontal lobe tumor composed of a cystic component with contrast-enhancing walls and a non-contrast-enhancing solid component. The patient underwent a gross total removal of the tumor. Histologically, the cystic and solid components showed oligodendroglioma and astrocytoma morphology, respectively. Immunohistochemically, IDH1-R132H staining was positive in the cystic component and negative in the solid component. Sanger sequencing confirmed the IDH1-R132H mutation and the C228T mutation in the telomerase reverse transcriptase promoter (TERTp) region in the cystic component, while both IDH1/2 and TERTp were wildtype in the solid component. Fluorescence in situ hybridization revealed 1p/19q-codeletion in both areas. The integrated diagnosis led to the diagnosis of oligoastrocytoma consisting of IDH-mutant 1p/19q-codeleted oligodendroglioma and IDH-wildtype astrocytoma. Furthermore, deoxyribonucleic acid (DNA) extracted separately from each area of formalin-fixed paraffin-embedded specimen revealed a distinct methylation profile. On the other hand, the global DNA copy-number analysis derived from the microarray data showed similar copy-number profiles including 1p/19q-codeletion for both sites. This is the first report of a dual-genotype oligoastrocytoma with IDH-mutant 1p/19q-codeleted oligodendroglioma and IDH-wildtype astrocytoma. This extremely rare case provides profound insight into the process of acquiring genetic abnormalities in the development of glioma.
Project description:To study the effects of IDH mutations, we collected and performed gene expression microarray analysis with tumor specimens from patients with grade II-III oligodendroglioma. Sequencing for mutations of IDH1 and IDH2 was done. Gene expression was compared between IDH wildtype vs. mutant samples
Project description:In the present work endothelial function in the aorta and femoral artery assessed in vivo by magnetic resonance imaging (MRI) was characterized in male and female 8-, 14-, 22-, 28-, and 40-week-old E3L.CETP and C57BL/6J mice. Vascular nitric oxide (NO), eicosanoids and hydrogen peroxide (H2O2) production in the aorta, were measured by electron paramagnetic resonance spectroscopy (EPR), mass spectrometry (LC/MS) and fluoresence assay, respectively. Endothelial-specific protein plasma biomarkers and global alterations in plasma proteome were asssesed by targeted and non-targeted preotomics, respectively. In C57BL/6J endothelial dysfunction was observed in 40-week-old female and male mice as evidenced by impaired endothelium-dependent vasodilation induced by acetylcholine (Ach) in the aorta or by flow in the femoral artery (flow-mediated vasodilation, FMD). In E3L.CETP mice age-dependent endothelial dysfunction was accelerated and appeared in 14-22-week-old male and 22-28-week-old female mice. In 40 week-old E3L.CETP mice endothelial dysfunction was severe in both male and female mice and was more pronounced as compared with age-matched C57BL/6J mice. Despite severe endothelial dysfunction in 40 week-old mice E3L.CETP mice neither in the aortic roots nor in brachiocephalic artery atherosclerotic plaques were not detected. Interestingly, in the presence of NOS-inhibitor (L-NAME), FMD was inhibited in all experimental groups. However, effect of L-NAME on Ach–induced vasodilation in E3L.CETP mice, was blunted as compared with C57BL/6J mice, in particular in young E3L.CETP female mice. Furthermore, Ach–induced vasodilation in the aorta was inhibited by catalase, while H2O2 production was increased, in young female but not in male E3L.CETP mice. A switch from NO to H2O2-dependent vasodilation in young female E3L.CETP mice was associated with a blunted systemic inflammation and lower number of differentially expressed proteins (DEPs) in plasma than in young E3L.CETP male mice as compared with age-and sex-matched C57BL/6J mice. However, female and male 40-week-old E3L.CETP mice displayed similar number of DEPs in plasma vs respective sex-matched younger E3L.CETP mice. In the present work endothelial function in the aorta and femoral artery assessed in vivo by magnetic resonance imaging (MRI) was characterized in male and female 8-, 14-, 22-, 28-, and 40-week-old E3L.CETP and C57BL/6J mice. Vascular nitric oxide (NO), eicosanoids and hydrogen peroxide (H2O2) production in the aorta, were measured by electron paramagnetic resonance spectroscopy (EPR), mass spectrometry (LC/MS) and fluoresence assay, respectively. Endothelial-specific protein plasma biomarkers and global alterations in plasma proteome were asssesed by targeted and non-targeted preotomics, respectively. In C57BL/6J endothelial dysfunction was observed in 40-week-old female and male mice as evidenced by impaired endothelium-dependent vasodilation induced by acetylcholine (Ach) in the aorta or by flow in the femoral artery (flow-mediated vasodilation, FMD). In E3L.CETP mice age-dependent endothelial dysfunction was accelerated and appeared in 14-22-week-old male and 22-28-week-old female mice. In 40 week-old E3L.CETP mice endothelial dysfunction was severe in both male and female mice and was more pronounced as compared with age-matched C57BL/6J mice. Despite severe endothelial dysfunction in 40 week-old mice E3L.CETP mice neither in the aortic roots nor in brachiocephalic artery atherosclerotic plaques were not detected. Interestingly, in the presence of NOS-inhibitor (L-NAME), FMD was inhibited in all experimental groups. However, effect of L-NAME on Ach–induced vasodilation in E3L.CETP mice, was blunted as compared with C57BL/6J mice, in particular in young E3L.CETP female mice. Furthermore, Ach–induced vasodilation in the aorta was inhibited by catalase, while H2O2 production was increased, in young female but not in male E3L.CETP mice. A switch from NO to H2O2-dependent vasodilation in young female E3L.CETP mice was associated with a blunted systemic inflammation and lower number of differentially expressed proteins (DEPs) in plasma than in young E3L.CETP male mice as compared with age-and sex-matched C57BL/6J mice. However, female and male 40-week-old E3L.CETP mice displayed similar number of DEPs in plasma vs respective sex-matched younger E3L.CETP mice.