Project description:PTPRD is a tumor suppressor of glioma that is frequently co-deleted with CDKN2A/p16. We show that Ptprd and p16 cooperate to promote gliomagenesis in the RCAS PDGFB / Nestin tv-A glioma mouse model. We found unique gene expression changes within tumor cells of Ptprd+/-p16-/- vs. Ptprd+/+p16-/- and Ptprd-/-p16-/- tumor cells. Neonatal mice were injected with RCAS PDGFB GFP. At symptoms, or at 12 weeks post injection, GFP+DAPI- tumor cells were sorted for RNA extraction and hybridization on Affymetrix microarrays. The mouse strain used was a mixed background of C57/BL6 and FVB/N. Ptprd mice were from Uetani et al. 2000 and p16/Nestin-tvA mice were from Tchouganouva et al. 2007.
Project description:PTPRD is a tumor suppressor of glioma that is frequently co-deleted with CDKN2A/p16. We show that Ptprd and p16 cooperate to promote gliomagenesis in the RCAS PDGFB / Nestin tv-A glioma mouse model. We found unique gene expression changes within tumor cells of Ptprd+/-p16-/- vs. Ptprd+/+p16-/- and Ptprd-/-p16-/- tumor cells.
Project description:Using the RCAS/tv-a system, we induced murine brainstem gliomas (PDGF-B; p53 loss using RCAS-Cre with and without H3.3K27M) in Nestin tv-a; p53 floxed mice
Project description:Diffuse intrinsic pontine glioma (DIPG) arises in the brainstem of children, leading tumor-related death among children. A heterozygous histone H3.3K27M mutation has been shown to occur in ~80% of DIPGs, and results in brainstem gliomagenesis. There is no clinical trial for the patients with DIPG that proved to prolong survival time so far. Recently, CDK4/6 inhibitor showed feasibility and early therapeutic effect against DIPG. Also, recent research with human DIPG specimens have detected the MAPK pathway highly activated. Here, we evaluated a novel combination therapy with CDK4/6 inhibitor and MEK inhibitor to the mouse DIPG model. In order to generate DIPG‐bearing mice, we are using the RCAS/Tv‐a system, with which we are able to target specific genetic alterations in RCAS viruses (avian retroviruses) to specific cells‐of‐origin using transgenic Tv‐a‐expressing mice (Tv‐a being the receptor for RCAS viruses). We injected P3‐P5 Nestin-Tv-a;p53fl/fl mice (C56Bl/6 background) with RCAS‐PDGF‐A + RCAS‐H3.3K27M, and RCAS-Cre. The mice are treated with vehicle (methylcellurose), ribociclib as monotherapy, trametinib as monotherapy, and ribociclib and combination as combination. For short-term use, tumor tissues treated with ribociclib showed cytostatic effect, and those treated with trametinib showed cytotoxic effect, and those with combination showed both. Long-term use showed that combination therapy modestly prolonged mice survival compared with vehicle. Therefore, we need to find how DIPG showed registence to the long-term chemotherapy.
Project description:Pediatric high-grade gliomas (pHGGs) are an aggressive pediatric CNS tumor, often characterized by mutations in H3F3A, the gene that encodes Histone H3.3 (H3.3). Substitution of the Glycine at position 34 of H3.3 with either Arginine or Valine (H3.3G34R/V), was recently described and characterized in a large cohort of pHGG samples as occurring in 5-20% of pHGGs. We developed a genetically engineered mouse model (GEMM) that incorporates PDGF-A activation, TP53 loss and the H3.3G34R mutation both in the presence and loss of Alpha thalassemia/mental retardation syndrome X-linked (ATRX), which is commonly mutated in H3.3G34 mutant pHGGs. Nestin Tv-a; p53 fl/fl and Nestin Tv-a; p53 fl/fl; ATRX fl/fl mice were injected with DF-1 cells transfected with RCAS-Cre, RCAS-PDGFA, and either RCAS-H3.3WT-GFP or RCAS-H3.3G34R-GFP. By 210 days old, a majority of mice develop symptoms of tumor growth (erratic behavior, domed head, ataxia) or have 20% weight loss and are euthanized. Our goal is to develop a biologically relevant animal model of pHGG in order to probe the downstream effects of the H3.3G34R mutation in the context of vital co-occurring mutations.
Project description:Here we describe the use of a high-throughput pipeline coupled to the commonly used tissue-specific retroviral RCAS-TVA mouse tumor model system. Utilizing next generation sequencing, we show that retroviral integration sites can be reproducibly detected in malignant stem cell lines generated from RCAS-PDGFB-driven glioma biopsies.
Project description:Akt is a robust oncogene that plays key roles in the development and progression of many cancers, including glioma. We evaluated the differential propensities of the Akt isoforms toward progression in the well-characterized RCAs/Ntv-a mouse model of PDGFB-driven low grade glioma. A constitutively active myristoylated form of Akt1 did not induce high-grade glioma (HGG). In stark contrast, Akt2 and Akt3 showed strong progression potential with 78% and 97% of tumors diagnosed as HGG, respectively. We further revealed that significant variations in polarity and hydropathy values among the Akt isoforms in both the pleckstrin homology domain (P domain) and regulatory domain (R domain) were critical in mediating glioma progression. Gene expression profiles from representative Akt-derived tumors indicated dominant and distinct roles for Akt3, consisting primarily of DNA repair pathways. TCGA data from human GBM closely reflected the DNA repair function, as Akt3 was significantly correlated with a 76 gene signature DNA repair panel. Consistently, compared to Akt1 and Akt2 overexpression models, Akt3-expressing human GBM cells had enhanced activation of DNA repair proteins, leading to increased DNA repair and subsequent resistance to radiation and temozolomide. Given the wide range of Akt3-amplified cancers, Akt3 may represent a key resistance factor. 5 different experimental conditions were compared (including GFP, PDGFB, PDGFB in conjunciton with Akt1, Akt2, or Akt3) with 3 mice per treatment
Project description:Diffuse midline glioma (DMG) is a type of lethal brain tumor that develops mainly in children. The majority of DMG harbor the K27M mutation in histone H3. Oligodendrocyte progenitor cells (OPCs) in the brainstem are candidate cells-of-origin for DMG, yet there is no genetically engineered mouse model of DMG initiated in OPCs. Here, we used the RCAS/Tv-a avian retroviral system to generate DMG in Olig2-expressing progenitors and Nestin-expressing progenitors in the neonatal mouse brainstem. PDGF-A or PDGF-B overexpression, along with p53 deletion, resulted in gliomas in both models. Exogenous overexpression of H3.3K27M had a significant effect on tumor latency and tumor cell proliferation when compared with H3.3WT in Nestin+ cells but not in Olig2+ cells. Further, the fraction of H3.3K27M-positive cells was significantly lower in DMGs initiated in Olig2+ cells relative to Nestin+ cells, both in PDGF-A and PDGF-B-driven models, suggesting that the requirement for H3.3K27M is increased when tumorigenesis is initiated in Nestin+ cells. Therefore, we need to find how the tumorigenic effects of H3.3K27M are more oncogenic in Nestin+ cells than Olig2+ cells.
Project description:Diffuse midline glioma (DMG) is a type of lethal brain tumor that develops mainly in children. The majority of DMG harbor the K27M mutation in histone H3. Oligodendrocyte progenitor cells (OPCs) in the brainstem are candidate cells-of-origin for DMG, yet there is no genetically engineered mouse model of DMG initiated in OPCs. Here, we used the RCAS/Tv-a avian retroviral system to generate DMG in Olig2-expressing progenitors and Nestin-expressing progenitors in the neonatal mouse brainstem. PDGF-B overexpression, along with p53 deletion, resulted in gliomas. Exogenous overexpression of H3.3K27M had a significant effect on tumor latency and tumor cell proliferation when compared with H3.3WT in Nestin+ cells but not in Olig2+ cells. Further, the fraction of H3.3K27M-positive cells was significantly lower in DMGs initiated in Olig2+ cells relative to Nestin+ cells, suggesting that the requirement for H3.3K27M is reduced when tumorigenesis is initiated in Olig2+ cells. Interestingly, H3K27 trimethylation was decreased with H3.3K27M induction even in Olig2+ cells. Therefore, we need to find if there is transcriptional changes for the tumorigenesis with H3.3K27M in Olig2+ cells.
Project description:Diffuse midline glioma (DMG) is a type of lethal brain tumor that develops mainly in children. The majority of DMG harbor the K27M mutation in histone H3. Oligodendrocyte progenitor cells (OPCs) in the brainstem are candidate cells-of-origin for DMG, yet there is no genetically engineered mouse model of DMG initiated in OPCs. Here, we used the RCAS/Tv-a avian retroviral system to generate DMG in Olig2-expressing progenitors and Nestin-expressing progenitors in the neonatal mouse brainstem. PDGF-A overexpression, along with p53 deletion, resulted in gliomas. Exogenous overexpression of H3.3K27M had a significant effect on tumor latency and tumor cell proliferation when compared with H3.3WT in Nestin+ cells but not in Olig2+ cells. Further, the fraction of H3.3K27M-positive cells was significantly lower in DMGs initiated in Olig2+ cells relative to Nestin+ cells, suggesting that the requirement for H3.3K27M is reduced when tumorigenesis is initiated in Olig2+ cells. Interestingly, H3K27 trimethylation was decreased with H3.3K27M induction even in Olig2+ cells. Therefore, we need to find if there is transcriptional changes for the tumorigenesis with H3.3K27M in Olig2+ cells.