Homo sapiens
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ABSTRACT:
PROVIDER: PRJNA255405 | ENA |
REPOSITORIES: ENA
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Project description:Bevacizumab induces glioblastoma resistance in two in vivo xenograft models. Two cell lines were developed with acquired resistance to bevacizumab. Gene expression difference were analyzed between treated and untreated tumors. Purpose: Antiangiogenic therapy reduces vascular permeability and delays progression but may ultimately promote an aggressive treatment-resistant phenotype. The aim of the present study was to identify mechanisms responsible for glioblastoma resistance to antiangiogenic therapy. Experimental Design: Glioma stem cell (GSC) NSC11 and U87 cell lines with acquired resistance to bevacizumab were developed from orthotopic xenografts in nude mice treated with bevacizumab. Genome-wide analyses were used to identify changes in tumor subtype and specific factors associated with resistance. Results: Mice with established parental NSC11 and U87 cells responded to bevacizumab, whereas glioma cell lines derived at the time of acquired resistance to anti-VEGF therapy were resistant to bevacizumab and did not have prolongation of survival compared to untreated controls. Gene expression profiling comparing anti-VEGF therapy-resistant cell lines to untreated controls demonstrated an increase in genes associated with a mesenchymal origin, cellular migration/invasion, and inflammation. Gene Set Enrichment Analysis (GSEA) demonstrated that bevacizumab-treated tumors showed a highly significant correlation to published mesenchymal gene signatures. Mice bearing resistant tumors showed significantly greater infiltration of myeloid cells in NSC11 and U87 resistant tumors. Invasion-related genes were also upregulated in both NSC11 and U87 resistant cells, which had higher invasion rates in vitro compared with their respective parental cell lines. Conclusions: Our studies identify multiple pro-inflammatory factors associated with resistance and identify a proneural-to-mesenchymal transition (PMT) in tumors resistant to antiangiogenic therapy. Glioma cell lines were injected into the caudate of nude mice and were allowed to grow untreated (samples labeled control) or were treated with 10 mg/kg IP twice weekly with bevacizumab (samples labeled Avastin). At the time of animal death, tumor tissue from the mouse was removed, and RNA was isolated and analyzed using gene expression. U87R and NSC11R represent cells resistant to bevacizumab (Avastin).
2013-07-01 | E-GEOD-45161 | biostudies-arrayexpress
Project description:Bevacizumab represents anti-angiogenic effect in cancer patients by inhibiting vascular endothelial growth factor (VEGF). However, its use is still limited due to the resistance to the initial response. Such resistance could be regulated by various cell types and soluble factors, although the underlying mechanisms, especially cell-based mechanisms, remain incompletely understood. Here, we identified bone marrow-derived fibrocytes as a novel contributor for the acquired resistance to bevacizumab, defined as alpha-1 type I collagen-positive and CXCR4-positive cells. In mouse models of lung cancer and malignant pleural mesothelioma, fibrocytes mediated the resistance to bevacizumab as a main producer of fibroblast growth factor 2. Using clinical specimens of lung cancer that were surgically resected after bevacizumab treatment, we demonstrated that the number of fibrocytes was significantly increased in bevacizumab-treated tumor, and was correlated with the number of treatment cycles as well as CD31-positive vessels. Our results identify fibrocytes as a promising cell biomarker and a potential therapeutic target to overcome resistance to anti-VEGF therapy.
2015-12-03 | GSE59476 | GEO
Project description:Acquired resistance with epigenetic alterations under long-term anti-angiogenic therapy for hepatocellular carcinoma
| PRJNA361255 | ENA
Project description:Bevacizumab induces glioblastoma resistance in two in vivo xenograft models. Two cell lines were developed with acquired resistance to bevacizumab. Gene expression difference were analyzed between treated and untreated tumors. Purpose: Antiangiogenic therapy reduces vascular permeability and delays progression but may ultimately promote an aggressive treatment-resistant phenotype. The aim of the present study was to identify mechanisms responsible for glioblastoma resistance to antiangiogenic therapy. Experimental Design: Glioma stem cell (GSC) NSC11 and U87 cell lines with acquired resistance to bevacizumab were developed from orthotopic xenografts in nude mice treated with bevacizumab. Genome-wide analyses were used to identify changes in tumor subtype and specific factors associated with resistance. Results: Mice with established parental NSC11 and U87 cells responded to bevacizumab, whereas glioma cell lines derived at the time of acquired resistance to anti-VEGF therapy were resistant to bevacizumab and did not have prolongation of survival compared to untreated controls. Gene expression profiling comparing anti-VEGF therapy-resistant cell lines to untreated controls demonstrated an increase in genes associated with a mesenchymal origin, cellular migration/invasion, and inflammation. Gene Set Enrichment Analysis (GSEA) demonstrated that bevacizumab-treated tumors showed a highly significant correlation to published mesenchymal gene signatures. Mice bearing resistant tumors showed significantly greater infiltration of myeloid cells in NSC11 and U87 resistant tumors. Invasion-related genes were also upregulated in both NSC11 and U87 resistant cells, which had higher invasion rates in vitro compared with their respective parental cell lines. Conclusions: Our studies identify multiple pro-inflammatory factors associated with resistance and identify a proneural-to-mesenchymal transition (PMT) in tumors resistant to antiangiogenic therapy.
2013-07-01 | GSE45161 | GEO
Project description:Increased levels of hypoxia and hypoxia inducible factor 1α (HIF-1α) in human sarcomas correlate with tumor progression and radiation resistance. Prolonged anti-angiogenic therapy of tumors can delay tumor growth but may also increase hypoxia and HIF-1α activity. In our recent clinical trial, treatment with the anti-vascular endothelial growth factor A (VEGF-A) antibody, bevacizumab, followed by a combination of bevacizumab and radiation led to near complete necrosis in nearly half of sarcomas. Gene set enrichment analysis of microarrays from pre-treatment biopsies found the Gene Ontology category “Response to hypoxia” was upregulated in poor responders, and hierarchical clustering based on 140 hypoxia-responsive genes separated poor responders from good responders. The most commonly used chemotherapeutic drug for sarcomas, doxorubicin (Dox), was recently found to block HIF-1α binding to DNA at low metronomic doses. We thus examined Dox treatment in 4 sarcoma cell lines, and found Dox at low concentrations (1-10 uM) blocked HIF-1α induction of VEGF-A by 84-97%, while inhibition of other HIF-1α-target genes including CA9, c-Met and FOXM1 was variable. HT1080 sarcoma xenografts had increased hypoxia and/or HIF-1α activity with increasing tumor size and with anti-VEGF receptor antibody (DC101) treatment. Combining DC101 and metronomic Dox had a synergistic effect in suppressing growth of HT1080 xenografts, primarily via induction of tumor endothelial cell apoptosis. In conclusion, sarcomas respond to increased hypoxia by expressing HIF-1α-target genes which may promote resistance to anti-angiogenic and other therapies. Metronomic Dox can block HIF-1α activation of target genes and works synergistically with anti-VEGF therapy to inhibit sarcomas. Pre-treatment biopsies were collected from 16 human sarcoma. The gene expression analysis was performed using Illumina platform.
2011-08-29 | E-GEOD-31715 | biostudies-arrayexpress
Project description:To investigate the possible mechanism of bevacizumab resistance in ovarian cancer ,we examined the changes in gene expression of SKOV3 before and after bevacizumab intervention. Results provide insight into molecular mechanisms of acquired resistance to bevacizumab in ovarian cancer.
2023-12-31 | GSE165419 | GEO
Project description:Recent randomized clinical trial revealed the additional effect of bevacizumab, a humanized monoclonal antibody against vascular endothelial growth factor (VEGF)-A, to conventional chemotherapy on survival of patients with metastatic colorectal cancer. However, a number of preclinical reports indicate resistant mechanisms to anti-angiogenic therapy in several tumor models. We investigated the phenotypic alterations of colorectal cancer xenograft during antiangiogenic therapy.
2013-05-25 | GSE47087 | GEO
Project description:Bevacizumab is an approved anti-angiogenic drug for patients with metastasized colorectal cancer (mCRC) targeting VEGF. The survival benefit of anti-VEGF therapy in mCRC patients is limited to a few months and acquired resistance mechanisms are greatly unknown. Using plasma DNA, we studied the evolution of tumor genomes in a cohort of patients with mCRC (n=150) and observed a recurrent focal amplification (8.7% of cases) on chromosome 13q12.2. Analysis of TCGA data (n=619) suggested an association with later stages, which we confirmed by longitudinal plasma analyses. We defined the minimally amplified region and studied the mechanistic consequences of copy number gain of the involved genes. The amplification of one gene, POLR1D, impacted cell proliferation, resulting in upregulation of VEGFA, an important regulator of angiogenesis which has been implicated in the resistance to bevacizumab. In several patients, we observed the emergence of this 13q12.2 amplicon under bevacizumab treatment, which was invariably associated with evolution of therapy resistance. Hence, we describe a novel resistance mechanism against a widely applied treatment in mCRC patients which will impact clinical management .
| EGAD00001005761 | EGA
Project description:Bevacizumab is an approved anti-angiogenic drug for patients with metastasized colorectal cancer (mCRC) targeting VEGF. The survival benefit of anti-VEGF therapy in mCRC patients is limited to a few months and acquired resistance mechanisms are greatly unknown. Using plasma DNA, we studied the evolution of tumor genomes in a cohort of patients with mCRC (n=150) and observed a recurrent focal amplification (8.7% of cases) on chromosome 13q12.2. Analysis of TCGA data (n=619) suggested an association with later stages, which we confirmed by longitudinal plasma analyses. We defined the minimally amplified region and studied the mechanistic consequences of copy number gain of the involved genes. The amplification of one gene, POLR1D, impacted cell proliferation, resulting in upregulation of VEGFA, an important regulator of angiogenesis which has been implicated in the resistance to bevacizumab. In several patients, we observed the emergence of this 13q12.2 amplicon under bevacizumab treatment, which was invariably associated with evolution of therapy resistance. Hence, we describe a novel resistance mechanism against a widely applied treatment in mCRC patients which will impact clinical management
| EGAS00001003791 | EGA
Project description:Recent randomized clinical trial revealed the additional effect of bevacizumab, a humanized monoclonal antibody against vascular endothelial growth factor (VEGF)-A, to conventional chemotherapy on survival of patients with metastatic colorectal cancer. However, a number of preclinical reports indicate resistant mechanisms to anti-angiogenic therapy in several tumor models. We investigated the phenotypic alterations of colorectal cancer xenograft during antiangiogenic therapy. TK-4, a solid tumor strain derived from human colon cancer, was orthotopically implanted into cecal walls of nude mice and treated with anti-VEGF antibody or control IgG for 35 days. Gene expression was analyzed using microarrays (Human Gene 1.0ST Array, Affymetrix).
2013-05-25 | E-GEOD-47087 | biostudies-arrayexpress