EGFRvIII vs. Control - xenograft glioblastomas
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
SUBMITTER: Anderson Erik
PROVIDER: S-ECPF-GEOD-46028 | biostudies-other |
REPOSITORIES: biostudies-other
Similar Datasets
Project description:Glioblastoma cell lines were xenografted onto mice and resulting tumors were profiled by microarray. Xenograft recipient mice were NOD/SCID/gamma (NSG) male mice 3 months old.
2013-07-01 | GSE46028 | GEO
Project description:Glioblastoma cell lines were xenografted onto mice and resulting tumors were profiled by microarray. Xenograft recipient mice were NOD/SCID/gamma (NSG) male mice 3 months old. In this set, 6 total samples were analyzed. There were three biological replicates for each of two conditions: EGFRvIII containing tumors and control. Arrays were analyzed for gene expression using GeneBase and for alternative splicing using MADS+ software.
2013-07-01 | E-GEOD-46028 | biostudies-arrayexpress
Project description:We identified a synthetic lethality between PLK1 silencing and the expression of an oncogenic Epidermal Growth Factor Receptor, EGFRvIII. PLK1 promoted homologous recombination (HR), mitigating EGFRvIII induced oncogenic stress resulting from DNA damage accumulation. Accordingly, PLK1 inhibition enhanced the cytotoxic effects of the DNA damaging agent, temozolomide (TMZ). This effect was significantly more pronounced in an Ink4a/Arf(-/-) EGFRvIII glioblastoma model relative to an Ink4a/Arf(-/-) PDGF-β model. The tumoricidal and TMZ-sensitizing effects of BI2536 were uniformly observed across Ink4a/Arf(-/-) EGFRvIII glioblastoma clones that acquired independent resistance mechanisms to EGFR inhibitors, suggesting these resistant clones retain oncogenic stress that required PLK1 compensation. Although BI2536 significantly augmented the anti-neoplastic effect of EGFR inhibitors in the Ink4a/Arf(-/-) EGFRvIII model, durable response was not achieved until TMZ was added. Our results suggest that optimal therapeutic effect against glioblastomas requires a "multi-orthogonal" combination tailored to the molecular physiology associated with the target cancer genome.
| S-EPMC4494902 | biostudies-literature
Project description:The EGFR/PI3K/Akt/mTOR signaling pathway is activated in many cancers including glioblastoma, yet mTOR inhibitors have largely failed to show efficacy in the clinic. Rapamycin promotes feedback activation of Akt in some patients, potentially underlying clinical resistance and raising the need for alternative approaches to block mTOR signaling. AMPK is a metabolic checkpoint that integrates growth factor signaling with cellular metabolism, in part by negatively regulating mTOR. We used pharmacological and genetic approaches to determine whether AMPK activation could block glioblastoma growth and cellular metabolism, and we examined the contribution of EGFR signaling in determining response in vitro and in vivo. The AMPK-agonist AICAR, and activated AMPK adenovirus, inhibited mTOR signaling and blocked the growth of glioblastoma cells expressing the activated EGFR mutant, EGFRvIII. Across a spectrum of EGFR-activated cancer cell lines, AICAR was more effective than rapamycin at blocking tumor cell proliferation, despite less efficient inhibition of mTORC1 signaling. Unexpectedly, addition of the metabolic products of cholesterol and fatty acid synthesis rescued the growth inhibitory effect of AICAR, whereas inhibition of these lipogenic enzymes mimicked AMPK activation, thus demonstrating that AMPK blocked tumor cell proliferation primarily through inhibition of cholesterol and fatty acid synthesis. Most importantly, AICAR treatment in mice significantly inhibited the growth and glycolysis (as measured by (18)fluoro-2-deoxyglucose microPET) of glioblastoma xenografts engineered to express EGFRvIII, but not their parental counterparts. These results suggest a mechanism by which AICAR inhibits the proliferation of EGFRvIII expressing glioblastomas and point toward a potential therapeutic strategy for targeting EGFR-activated cancers.
| S-EPMC2714280 | biostudies-literature
Project description:BackgroundThe efficacy of novel targeted therapies is often tested at the time of tumor recurrence. However, for glioblastoma (GBM) patients, surgical resections at recurrence are performed only in a minority of patients; therefore, molecular data are predominantly derived from the initial tumor. Molecular data of the initial tumor for patient selection into personalized medicine trials can therefore be used only when the specific genetic change is retained in the recurrent tumor.MethodsIn this study we determined whether EGFR amplification and expression of the most common mutation in GBMs (EGFRvIII) is retained at tumor recurrence. Because retention of genetic changes may be dependent on the initial treatment, we only used a cohort of GBM samples that were uniformly treated according to the current standard of care (ie, chemo-irradiation with temozolomide).ResultsOur data show that, in spite of some quantitative differences, the EGFR amplification status remains stable in the majority (84%) of tumors evaluated. EGFRvIII expression remained similar in 79% of GBMs. However, within the tumors expressing EGFRvIII at initial diagnosis, approximately one-half lose their EGFRvIII expression at tumor recurrence.ConclusionsThe relative stability of EGFR amplification indicates that molecular data obtained in the primary tumor can be used to predict the EGFR status of the recurrent tumor, but care should be taken in extrapolating EGFRvIII expression from the primary tumor, particularly when expressed at first diagnosis.
| S-EPMC5762005 | biostudies-literature
Project description:Glioblastoma is the most aggressive malignant brain tumor among all primary brain and central nervous system tumors. The median survival time for glioblastoma patients given the current standard of care treatment (surgery, radiation, and chemotherapy) is less than 15 months. Thus, there is an urgent need to develop more efficient therapeutics to improve the poor survival rates of patients with glioblastoma. To address this need, we have developed a novel tumor-targeted immunotoxin (IT), D2C7-(scdsFv)-PE38KDEL (D2C7-IT), by fusing the single chain variable fragment (scFv) from the D2C7 monoclonal antibody (mAb) with the Pseudomonas Exotoxin (PE38KDEL). D2C7-IT reacts with both the wild-type epidermal growth factor receptor (EGFRwt) and EGFR variant III (EGFRvIII), two onco-proteins frequently amplified or overexpressed in glioblastomas. Surface plasmon resonance and flow cytometry analyses demonstrated a significant binding capacity of D2C7-IT to both EGFRwt and EGFRvIII proteins. In vitro cytotoxicity data showed that D2C7-IT can effectively inhibit protein synthesis and kill a variety of EGFRwt-, EGFRvIII-, and both EGFRwt- and EGFRvIII-expressing glioblastoma xenograft cells and human tumor cell lines. Furthermore, D2C7-IT exhibited a robust anti-tumor efficacy in orthotopic mouse glioma models when administered via intracerebral convection-enhanced delivery (CED). A preclinical toxicity study was therefore conducted to determine the maximum tolerated dose (MTD) and no-observed-adverse-effect-level (NOAEL) of D2C7-IT via intracerebral CED for 72 hours in rats. Based on this successful rat toxicity study, an Investigational New Drug (IND) application (#116855) was approved by the Food and Drug Administration (FDA), and is now in effect for a Phase I/II D2C7-IT clinical trial (D2C7 for Adult Patients with Recurrent Malignant Glioma, https://clinicaltrials.gov/ct2/show/NCT02303678). While it is still too early to draw conclusions from the trial, results thus far are promising.
| S-EPMC5341612 | biostudies-literature
Project description:Recent advances in single-cell RNA sequencing (scRNA-seq) have endowed researchers with the ability to detect and analyze the transcriptomes of individual cancer cells. In the present study, 16,128 tumor cells from EGFR wild-type and EGFRvIII mutant cells were profiled by scRNA-seq. Analyses of scRNA-seq data from both U87MG and U87MG-EGFRvIII libraries revealed inherent heterogeneity in gene expression and biological processes. The cells stably expressing EGFRvIII showed enhanced transcriptional activities and a relatively homogeneous pattern, which manifested as less diverse distributions, gene expression levels and functional annotations compared with those of cells expressing the nonmutated version. Moreover, the differentially expressed genes between the U87MG and U87MG-EGFRvIII groups were mainly enriched in DNA replication, DNA repair and angiogenesis. We compared scRNA-seq data with bulk RNA-seq and EGFRvIII xenograft RNA-seq data. RAD51AP1 was shown to be upregulated in all three databases. Further analysis of RAD51AP1 revealed that it is an independent prognostic factor of glioma. Knocking down RAD51AP1 significantly inhibited tumor volume in an intracranial EGFRvIII-positive GBM model and prolonged survival time. Collectively, our microfluidic-based scRNA-seq driven by a single genetic event revealed a previously unappreciated implication of EGFRvIII in the heterogeneity of GBM and identified RAD51AP1 as an oncogene in glioma.
| S-EPMC6781999 | biostudies-literature
Project description:mTOR pathway hyperactivation occurs in approximately 90% of glioblastomas, but the allosteric mTOR inhibitor rapamycin has failed in the clinic. Here, we examine the efficacy of the newly discovered ATP-competitive mTOR kinase inhibitors CC214-1 and CC214-2 in glioblastoma, identifying molecular determinants of response and mechanisms of resistance, and develop a pharmacologic strategy to overcome it.We conducted in vitro and in vivo studies in glioblastoma cell lines and an intracranial model to: determine the potential efficacy of the recently reported mTOR kinase inhibitors CC214-1 (in vitro use) and CC214-2 (in vivo use) at inhibiting rapamycin-resistant signaling and blocking glioblastoma growth and a novel single-cell technology-DNA Encoded Antibody Libraries-was used to identify mechanisms of resistance.Here, we show that CC214-1 and CC214-2 suppress rapamycin-resistant mTORC1 signaling, block mTORC2 signaling, and significantly inhibit the growth of glioblastomas in vitro and in vivo. EGFRvIII expression and PTEN loss enhance sensitivity to CC214 compounds, consistent with enhanced efficacy in strongly mTOR-activated tumors. Importantly, CC214 compounds potently induce autophagy, preventing tumor cell death. Genetic or pharmacologic inhibition of autophagy greatly sensitizes glioblastoma cells and orthotopic xenografts to CC214-1- and CC214-2-induced cell death.These results identify CC214-1 and CC214-2 as potentially efficacious mTOR kinase inhibitors in glioblastoma, and suggest a strategy for identifying patients most likely to benefit from mTOR inhibition. In addition, this study also shows a central role for autophagy in preventing mTOR-kinase inhibitor-mediated tumor cell death, and suggests a pharmacologic strategy for overcoming it.
| S-EPMC3815450 | biostudies-other
Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
| S-ECPF-GEOD-42670 | biostudies-other
Project description:BackgroundGlioblastoma multiforme is the most lethal brain tumor with limited therapeutic options. Antigens expressed on the surface of malignant cells are potential targets for antibody-mediated gene/drug delivery.Principal findingsIn this study, we investigated the ability of genetically modified human mesenchymal stem cells (hMSCs) expressing a single-chain antibody (scFv) on their surface against a tumor specific antigen, EGFRvIII, to enhance the therapy of EGFRvIII expressing glioma cells in vivo. The growth of U87-EGFRvIII was specifically delayed in co-culture with hMSC-scFvEGFRvIII. A significant down-regulation was observed in the expression of pAkt in EGFRvIII expressing glioma cells upon culture with hMSC-scFvEGFRvIII vs. controls as well as in EGFRvIII expressing glioma cells from brain tumors co-injected with hMSC-scFvEGFRvIII in vivo. hMSC expressing scFvEGFRvIII also demonstrated several fold enhanced retention in EGFRvIII expressing flank and intracranial glioma xenografts vs. control hMSCs. The growth of U87-EGFRvIII flank xenografts was inhibited by 50% in the presence of hMSC-scFvEGFRvIII (p<0.05). Moreover, animals co-injected with U87-EGFRvIII and hMSC-scFvEGFRvIII intracranially showed significantly improved survival compared to animals injected with U87-EGFRvIII glioma cells alone or with control hMSCs. This survival was further improved when the same animals received an additional dosage of hMSC-scFvEGFRvIII two weeks after initial tumor implantation. Of note, EGFRvIII expressing brain tumors co-injected with hMSCs had a lower density of CD31 expressing blood vessels in comparison with control tumors, suggesting a possible role in tumor angiogenesis.Conclusions/significanceThe results presented in this study illustrate that genetically modified MSCs may function as a novel therapeutic vehicle for malignant brain tumors.
| S-EPMC2841188 | biostudies-literature