Project description:Here we have used 4C-seq to interrogate the toplogy of the EGFR locus in glioblastoma models that are EGFR unamplified (GSC23) and amplified (GBM3565).
Project description:Background: Glioblastoma mortality is driven by tumour progression or recurrence despite administering a therapeutic arsenal consisting of surgical resection, radiation, and alkylating chemotherapy. The genetic changes underlying tumour progression and chemotherapy resistance are poorly understood. Methods: In this work, we sought to define the relationship between EGFR amplification status, EGFR mRNA expression, and EGFR pathway activity. We compared RNA-sequencing data from matched primary and recurrent tumour samples (N = 40 patients, 20 with EGFR amplification). Results: In the setting of glioblastoma recurrence, the EGFR pathway was overexpressed regardless of EGFR amplification status, suggesting a common genomic endpoint in recurrent glioblastoma, although EGFR amplification did associate with higher EGFR mRNA expression. Three of forty patients in the study cohort had EGFR-amplified tumours and received targeted EGFR therapy. Their molecular subtypes and clinical outcomes did not significantly differ from patients who received conventional chemotherapy. Conclusion: Our findings suggest that while the EGFR amplification may confer a unique molecular profile in primary glioblastoma, pathway analysis reveals upregulation of the EGFR pathway in recurrence, regardless of amplification status. As such, the EGFR pathway may be a key mediator of glioblastoma progression.
Project description:Epidermal Growth Factor Receptor (EGFR) gene amplification and mutations are the most common oncogenic events in Glioblastoma (GBM), but the mechanisms by which they promote aggressive tumor growth are not well understood. Here, through integrated epigenome and transcriptome analyses of cell lines, genotyped clinical samples and TCGA data, we show that EGFR mutations remodel the activated enhancer landscape of GBM, promoting tumorigenesis through a SOX9 and FOXG1-dependent transcriptional regulatory network in vitro and in vivo. The most common EGFR mutation, EGFRvIII, sensitizes GBM cells to the BET-bromodomain inhibitor JQ1 in a SOX9, FOXG1-dependent manner. These results identify the role of transcriptional/epigenetic remodeling in EGFR-dependent pathogenesis and suggest a mechanistic basis for epigenetic therapy. ChIP-Seq for H3K27ac, H3K4me1, and H3K4me3, and RNA-seq for Glioblastoma (GBM) cells and/or tissues with or without EGFRvIII mutation.
Project description:Co-amplification of EGFR and EGFRvIII, a tumor-specific truncation mutant of EGFR, represent hallmark genetic lesions in glioblastoma. We report that EGFR and EGFRvIII stimulate the innate immune defense receptor Toll-like Receptor 2 (TLR2); and that knockdown of TLR2 led to a dramatic survival advantage in glioblastoma xenografts. EGFR and EGFRvIII activated TLR2 in a ligand-independent manner, promoting tumor growth and immune evasion. We show that EGFR and EGFRvIII cooperate to activate the Rho-associated protein kinase ROCK2, modulating malignant progression both by activating TLR2 and WNT signaling, and through remodeling the tumor microenvironment.
Project description:Glioblastoma, the most frequent and malignant adult brain tumor has been extensively studied; yet no effective treatment exists. To overcome this dismal scenario, it is essential to improve preclinical biological models. This study aimed to establish and molecularly characterize glioblastoma primary cultures. Additionally, it intended to assess the efficacy of molecular-targeted therapies, in the presence of putative targeting cell lines. Five glioblastoma primary cultures were established exhibiting a diversity of chromosomal alterations by aCGH, with gain of chromosome 7 and loss of chromosome 10, 13 and 17p, the most frequent alterations. Mutation profiling by Ion Torrent and Sanger sequencing showed the present of hotspot mutations in TERT (4/5), TP53 (2/5) and RB, BRAF, PTEN and EGFR (1/5). A similar chromosomal and mutation pattern was observed in the primary cultures and matched frozen tumors. The MTS cell viability assay of the p.Gly598Val EGFR mutated cell line, revealed AST1306 as the most potent EGFR inhibitor, when compared with afatinib, erlotinib, or lapatinib. Herein, glioblastoma primary cultures were successfully established and molecularly characterized. Importantly, we showed that AST1306 inhibits EGFR mutated cells, suggesting that primary cultures are suitable in vitro models for glioblastoma biology and preclinical drugs studies. Two-color Agilent 8x60K array CGH (aCGH) was performed in 10 glioblastoma multiforme samples (CY3) and reference DNA (CY5). The 10 glioblastoma multiforme samples were: DNA extracted from 5 primary cultured cells; DNA of 5 primary tumors (matched with the 5 primary cell lines). Gender-matched commercial DNA of each case was used as control.
Project description:Glioblastoma, the most frequent and malignant adult brain tumor has been extensively studied; yet no effective treatment exists. To overcome this dismal scenario, it is essential to improve preclinical biological models. This study aimed to establish and molecularly characterize glioblastoma primary cultures. Additionally, it intended to assess the efficacy of molecular-targeted therapies, in the presence of putative targeting cell lines. Five glioblastoma primary cultures were established exhibiting a diversity of chromosomal alterations by aCGH, with gain of chromosome 7 and loss of chromosome 10, 13 and 17p, the most frequent alterations. Mutation profiling by Ion Torrent and Sanger sequencing showed the present of hotspot mutations in TERT (4/5), TP53 (2/5) and RB, BRAF, PTEN and EGFR (1/5). A similar chromosomal and mutation pattern was observed in the primary cultures and matched frozen tumors. The MTS cell viability assay of the p.Gly598Val EGFR mutated cell line, revealed AST1306 as the most potent EGFR inhibitor, when compared with afatinib, erlotinib, or lapatinib. Herein, glioblastoma primary cultures were successfully established and molecularly characterized. Importantly, we showed that AST1306 inhibits EGFR mutated cells, suggesting that primary cultures are suitable in vitro models for glioblastoma biology and preclinical drugs studies.
Project description:The goal of this study was to examine chromosome topology in Drosophila larval eye and antennal discs by identifying topologically associating domains (TADs) across the genome. TADs were compared between the eye and antennal disc to determine whether they contribute to cell-type-specific homologous pairing and transvection.
Project description:Epidermal Growth Factor Receptor (EGFR) gene amplification and mutations are the most common oncogenic events in Glioblastoma (GBM), but the mechanisms by which they promote aggressive tumor growth are not well understood. Here, through integrated epigenome and transcriptome analyses of cell lines, genotyped clinical samples and TCGA data, we show that EGFR mutations remodel the activated enhancer landscape of GBM, promoting tumorigenesis through a SOX9 and FOXG1-dependent transcriptional regulatory network in vitro and in vivo. The most common EGFR mutation, EGFRvIII, sensitizes GBM cells to the BET-bromodomain inhibitor JQ1 in a SOX9, FOXG1-dependent manner. These results identify the role of transcriptional/epigenetic remodeling in EGFR-dependent pathogenesis and suggest a mechanistic basis for epigenetic therapy.