ABSTRACT: Background: Signaling by receptor tyrosine kinases (RTK) is frequently dysregulated in gliomas. Inter-individual variability in the causes for dysregulated RTK signaling may have hampered the efficacy of targeted therapies. Using gene expression modules around key regulators in the RAS-RAF-MEK-MAPK cascade and in the phosphatidylinositol 3-kinase-AKT pathways, we developed a “RMPA” clustering scheme to distinguish gliomas with varying extents of RTK signaling. Results: We identified gene modules consistently co-expressed with NF1 (NF1-M), Sprouty (SPRY-M) and PTEN (PTEN-M) in gliomas. Their signatures enabled robust clustering of adult diffuse gliomas of WHO grades II-IV into RMPAhigh and RMPAlow phenotypes in a morphology-independent manner. In five independent data sets from three continents containing more than 1500 adult diffuse gliomas, RMPAhigh gliomas were associated with poor prognosis while RMPAlow gliomas were not. The RMPAhigh and RMPAlow glioma subtypes showed distinct levels of the activities of RAS-RAF-MEK-MAPK cascade and PI3K-AKT pathway and harbored unique sets of genomic alterations in the RTK signaling-related genes. The RMPAhigh gliomas contained large numbers of immature vessel cells and tumor associated macrophages and both cell types expressed high levels of pro-angiogenic RTKs including MET, VEGFR1, KDR, EPHB4 and NRP1. Conclusion: Inter-glioma variability in RTK signaling activities can be defined using the RMPA clustering scheme. The combined signatures of NF1-M, SPRY-M and PTEN-M reflect RTK signaling activity both in the glioma cells and in the glioma microenvironment. Our data show that RTK signaling in the glioma microenvironment may play a pivotal role in glioma progression. Transcriptome data from 22 fresh gliomas (2 astrocytoma II, 1 oligodendrocytoma II, 7 oligoastrocytoma II, 4 anaplastic oligoastrocytoma III and 8 GBM) were obtained using Affymetrix Human Gene 1.0 ST Array. Unsupervised hierarchical clustering of the expression data for the SPRY-M, NF1-M and PTEN-M was performed on these transcriptome data to identify samples with RMPAhigh or RMPAlow signature.
Project description:Primary glioblastoma, representing over 90% of adult glioblastoma, develop rapidly without preexisting lower-grade glioma. We have generated a mouse model of primary glioblastoma driven by a single p53 mutation. These p53-mutant gliomas lose the syntenic region of human chromosome 10q, which is mapped to mouse chr19 and chr7. Loss of mouse chr19, containing Pten, activates PI3K/Akt signaling. Rictor/mTORC2 deletion inhibits Akt signaling, causing a significant delay in p53-mutant driven glioma formation. Unexpectedly, Rictor/mTORC2 loss promotes p53-mutant driven medulloblastomas with unique features of pediatric SHH medulloblastoma. Mechanistically, Rictor/mTORC2 loss inhibits the generation of glioma precursor cells from neural stem/progenitor cells in the adult brain, while causing a delay in differentiation of granule cell precursors in the developing brain, a cell-of-origin of SHH medulloblastoma. Overall design: In this study we generate mouse models with (1) p53 loss (2) p53 loss combined with gemline Nf1 mutation (3) a conditional cis-p53/Nf1 mutation. We profiled the resultant tumors as well as normal forebrain and cerebellum as controls.
Project description:Gioma stem cells from Nf1-associated optic gliomas and NSCs from third ventricle zone show differencies in gene expression patterns and physiological functions. We used microarrays to identify differential gene expression between glioma stem cells and the control counterparts including the wild type and Nf1-/- neural stem cells from the third ventricle. Overall design: Cultured glioma stem cells were isolated from mouse optic gliomas. Wild-type and Nf1-/- TVZ NSCs were generated from postnantal day 1 Nf1flox/flox pups. We sought to obtain neural stem cells from three independent cultures. There are 9 samples in total. 3 wild-type TVZ NSCs, 3 Nf1-/- TVZ NSCs, 3 glioma stem cells.
Project description:The concept that solid tumors are maintained by a productive interplay between neoplastic and non-neoplastic elements has gained traction with the demonstration that stromal fibroblasts and immune system cells dictate cancer development and progression. While less studied, brain tumor (glioma) biology is likewise influenced by non-neoplastic immune system cells (macrophages and microglia) which interact with neoplastic glioma cells to create a unique physiological state (glioma ecosystem) distinct from that found in the normal tissue. To explore this neoplastic ground state, we leveraged several preclinical mouse models of neurofibromatosis type 1 (NF1) optic glioma, a low-grade astrocytoma whose formation and maintenance requires productive interactions between non-neoplastic and neoplastic cells, and employed whole tumor RNA-sequencing and mathematical deconvolution strategies to characterize this low-grade glioma ecosystem as an aggregate of cellular and acellular elements. Using this approach, we demonstrate that optic gliomas generated by altering the germline Nf1 gene mutation, the glioma cell of origin, or the presence of co-existing genetic alterations represent molecularly-distinct tumors. However, these optic glioma tumors share a 25-gene core signature, not found in normal optic nerve, that is normalized by microglia inhibition (minocycline), but not conventional (carboplatin) or molecularly-targeted (rapamycin) chemotherapy. Lastly, we identify a genetic signature conferred by Pten reduction and corrected by PI3K inhibition. This signature predicts progression-free survival in patients with either low-grade or high-grade glioma. Collectively, these findings support the concept that gliomas are composite ecological systems whose biology and response to therapy may be best defined by examining the tumor as a whole. Overall design: We profiled homogenized optic nerve, optic glioma tissue, and cell lines from mouse models and used a template-switching-based library construction protocol to faciliate low-input RNA-Seq.
Project description:miRNA expression analysis of mouse glioma and PNET. Glioma was developed from SVZ cells through conditional codeletion of Pten/p53 or Rb/p53; while PNET was developed by codeletion of Rb/p53. Overall design: Pten/p53 codeleted SVZ cells always developed gliomas, while Rb/p53 cells mainly gave rise to PNET, but a small amout of Rb/p53 mice developed gliomas. Three groups: Pten/p53 glioma, Rb/p53 glioma and Rb/p53 PNET; biological control: each RNA sample was from a mouse tumour, three samples in each group.
Project description:Mosaic Analysis with Double Markers (MADM) based glioma mouse model, which homozygously lacks Tp53 and Nf1, spontaneously developed gliomas at the post-natal 90-120 days. Tp53 and Nf1 are among the most frequently mutated genes in human glioma patients. Investigating the expression changes of genes induced by inactivation of Tp53 and Nf1 can be a clue to clarify the mechanism of gliomagenesis. We examined the expressions of glioma in MADM mouse at post-natal 150 days (n=3) and of normal brain in Tp53 and Nf1 wild type mouse at post-natal 150 days (n=2). We used SurePrint G3 Mouse GE 8×60K array slides (G4858A, Agilent Technologies). Overall design: Microarray experiment was performed as single-color hybridization on SurePrint G3 Mouse GE 8 x 60K array.
Project description:Solid cancers develop within a supportive microenvironment that promotes tumor formation and continued growth through the elaboration of mitogens and chemokines. Within these tumors, monocytes (macrophages and microglia) represent rich sources of these stromal factors. Leveraging a genetically-engineered mouse model of neurofibromatosis type 1 (NF1) low-grade brain tumor (optic glioma), previous studies have demonstrated that microglia are important for glioma formation and maintenance. To identify the tumor-associated microglial factors that support glioma growth (gliomagens), we employed a comprehensive large scale discovery effort using optimized advanced RNA-sequencing methods. Candidate gliomagens were prioritized to identify potential secreted or membrane-bound proteins, which were next validated by quantitative RT-PCR and RNA FISH following minocycline-mediated microglial inactivation in vivo. Using these selection criteria, Ccl5 was identified as a highly expressed chemokine in both genetically engineered Nf1 mouse and human optic gliomas. As a candidate gliomagen, recombinant Ccl5 increased Nf1-deficient optic nerve astrocyte growth in vitro. Importantly, consistent with its critical role in maintaining tumor growth, Ccl5 inhibition with neutralizing antibodies reduced Nf1 mouse optic glioma growth in vivo. Collectively, these findings establish Ccl5 as critical stromal growth factor in low-grade glioma maintenance relevant to future microglia-targeted therapies for brain tumors. Overall design: Nf1 optic glioma associated microglia from mice were flow sorted. Upregulated genes of glioma associated microglia were verified and further examined.
Project description:Gliomas are aggressive primary brain tumors, presenting surgery limitations due to their highly infiltrative potential. The expression of Angiotensin II (Ang II) receptors in human astrocytomas was previously associated with a poor prognosis. Accordingly, this study was undertaken to reveal the molecular mechanisms underlying Ang II actions in gliomas through the transcriptomic analysis of glioma cells exposed to Ang II. C6 glioma cells were treated with Ang II and specific antagonists of AT1 and AT2. Total RNA was isolated at three and six hours intervals and submitted to oligonucleotide microarray protocol. The differentially expressed genes were obtained by paired t-tests with p<0.05 and interpreted using Venn diagrams, functional enrichment and protein interaction network analyses. Validation of microarray results was carried out through qPCR experiments of selected genes. We found a high number of significant genes with low fold changes in gene expression at the time intervals studied. These genes were regulated in a time dependent-manner, with most gene expression changes being exclusive to one of the time intervals evaluated. Our results indicated that blocking AT1 or AT2 changed the expression of genes involved in regulation of transcription, cell cycle, cell proliferation, differentiation, apoptosis, cell adhesion, cell migration, regulation of actin cytoskeleton, protein transport and protein ubiquitination. Additionally, the signaling pathways over-represented by the significant genes were ErbB, mTOR, MAPK, neurotrophin, insulin and Wnt. Finally, interactome analyses revealed hub genes associated with cell proliferation, survival, migration, transport, structural support, neurotrophin pathway, MAPK signaling and Wnt signaling. Taken together, our findings implicate Ang II-transcriptional regulation in glioma progression by means of the modulation of genes participating in protumoral functions. This transcriptome pattern is observed upon Ang II activation of either AT1 or AT2 receptors, thereby highlighting the relevance of both receptor subtypes in glioma progression. Interactome analyses disclosed hub genes regulated by Ang II which may present higher control over their networks. These genes participate in biological functions that could enhance the degree of malignancy in gliomas and thus should be further explored. C6 cells were cultured in Dulbecco's modified Eagle's medium (DMEM) supplemented with 10% fetal bovine serum, 100 Units/ml penicillin and 100 µg/ml streptomycin. Cells were seeded in cell culture dishes and incubated at 37°C/ 5% CO2 until becoming confluent. Then, these cells were pre-treated (30 minutes) with either AT1 receptor antagonist (Losartan: 10-5M) or AT2 receptor antagonist (PD123319: 10-5M) followed by Ang II treatment (10-7 M) according to the treatment scheme: Group 1 – control; Group 2 – cells only treated with Ang II; Group 3 – cells pre-treated (30 minutes) with Losartan and then treated with Ang II; Group 4 – cells pre-treated (30 minutes) with PD123319 and then treated with Ang II. To identify which genes were significantly differentially expressed, paired t-tests (p<0.05) were performed in the following comparisons: Ang II x Control (3h); Ang II x Control (6h); Ang II +Los x Ang II (3h); Ang II +Los x Ang II (6h); Ang II +PD123319 x Ang II (3h); Ang II +PD123319 x Ang II (6h).
Project description:The paper describes a model of glioma.
Created by COPASI 4.26 (Build 213)
This model is described in the article:
A mathematical model of pre-diagnostic glioma growth
Marc Sturrock, Wenrui Hao, Judith Schwartzbaum, Grzegorz A. Rempala
J Theor Biol. 2015 September 7; 380: 299–308
Due to their location, the malignant gliomas of the brain in humans are very difficult to treat in advanced stages. Blood-based biomarkers for glioma are needed for more accurate evaluation of treatment response as well as early diagnosis. However, biomarker research in primary brain tumors is challenging given their relative rarity and genetic diversity. It is further complicated by variations in the permeability of the blood brain barrier that affects the amount of marker released into the bloodstream. Inspired by recent temporal data indicating a possible decrease in serum glucose levels in patients with gliomas yet to be diagnosed, we present an ordinary differential equation model to capture early stage glioma growth. The model contains glioma-glucose-immune interactions and poses a potential mechanism by which this glucose drop can be explained. We present numerical simulations, parameter sensitivity analysis, linear stability analysis and a numerical experiment whereby we show how a dormant glioma can become malignant.
To cite BioModels Database, please use: BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models .
To the extent possible under law, all copyright and related or neighbouring rights to this encoded model have been dedicated to the public domain worldwide.
Please refer to CC0 Public Domain Dedication for more information.
Project description:How malignant gliomas arise in a mature brain remains a mystery, hindering the development of preventive and therapeutic interventions. We previously showed that oligodendrocyte precursor cells (OPCs) can be transformed into glioma when mutations are introduced perinatally. However, adult OPCs rarely proliferate compared to their perinatal counterparts. Whether these relatively quiescent cells have the potential to transform is unknown, which is a critical question considering the late onset of human glioma. Additionally, the events taking place between initial mutation and a fully developed tumor mass (pre-malignant phase) are particularly poorly understood in glioma. Here we used a temporally controllable Cre transgene to delete p53 and NF1 specifically in adult OPCs, and demonstrated that these cells consistently give rise to malignant gliomas. To investigate the transforming process of quiescent adult OPCs, we then tracked these cells throughout the pre-malignant phase, which revealed a dynamic multi-step transformation, starting with rapid but transient hyper-proliferative reactivation, followed by a long period of dormancy, then final malignant transformation. Using pharmacological approaches, we discovered that mTOR signaling is critical for both the initial OPC reactivation step and late stage tumor cell proliferation, and thus might be a potential target for both glioma prevention and treatment. In summary, our results firmly establish the transforming potential of adult OPCs, and reveal an actionable multi-phasic reactivation process that turns slowly dividing OPCs into malignant gliomas. 44K Mouse Development Oligo Microarrays from Agilent Technologies were used for microarray analysis. For each experiment, total RNA was fluorescently labeled and hybridized directly against a common reference sample generated from the RNA pool of four WT P17 mouse brain neocortex.
Project description:Faratian2009 - Role of PTEN in Trastuzumab
This model is described in the article:
reveals new strategies for personalizing cancer medicine and
confirms the role of PTEN in resistance to trastuzumab.
Faratian D, Goltsov A, Lebedeva G,
Sorokin A, Moodie S, Mullen P, Kay C, Um IH, Langdon S, Goryanin
I, Harrison DJ.
Cancer Res. 2009 Aug; 69(16):
Resistance to targeted cancer therapies such as trastuzumab
is a frequent clinical problem not solely because of
insufficient expression of HER2 receptor but also because of
the overriding activation states of cell signaling pathways.
Systems biology approaches lend themselves to rapid in silico
testing of factors, which may confer resistance to targeted
therapies. Inthis study, we aimed to develop a new kinetic
model that could be interrogated to predict resistance to
receptor tyrosine kinase (RTK) inhibitor therapies and directly
test predictions in vitro and in clinical samples. The new
mathematical model included RTK inhibitor antibody binding,
HER2/HER3 dimerization and inhibition, AKT/mitogen-activated
protein kinase cross-talk, and the regulatory properties of
PTEN. The model was parameterized using quantitative
phosphoprotein expression data from cancer cell lines using
reverse-phase protein microarrays. Quantitative PTEN protein
expression was found to be the key determinant of resistance to
anti-HER2 therapy in silico, which was predictive of unseen
experiments in vitro using the PTEN inhibitor bp(V). When
measured in cancer cell lines, PTEN expression predicts
sensitivity to anti-HER2 therapy; furthermore, this
quantitative measurement is more predictive of response
(relative risk, 3.0; 95% confidence interval, 1.6-5.5; P <
0.0001) than other pathway components taken in isolation and
when tested by multivariate analysis in a cohort of 122 breast
cancers treated with trastuzumab. For the first time, a systems
biology approach has successfully been used to stratify
patients for personalized therapy in cancer and is further
compelling evidence that PTEN, appropriately measured in the
clinical setting, refines clinical decision making in patients
treated with anti-HER2 therapies.
This model is hosted on
and identified by:
To cite BioModels Database, please use:
An enhanced, curated and annotated resource for published
quantitative kinetic models.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to
the public domain worldwide. Please refer to
Public Domain Dedication for more information.