Suppression of MicroRNA-9 by Mutant EGFR Signaling Induces FOXP1 to Enhance Glioblastoma Tumorigenicity
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ABSTRACT: The EGF-receptor (EGFR) is amplified and mutated in glioblastoma (GBM) where its common mutation, (∆EGFR, also called EGFRvIII) has a variety of activities that promote growth and inhibit death, thereby conferring a strong tumor-enhancing effect. This range of activities suggested to us that ∆EGFR might exert its influence through pleiotropic effectors and we hypothesized that microRNAs (miRs) might serve such a function. To test this, we determined the miR profiles of GBM cells with activated wild type EGFR (wtEGFR) and mutant EGFR (∆EGFR) to cells with non-activated EGFR or kinase dead ∆EGFR. To identify miRs regulated by EGFR, RNA from 2 different glioma cell lines (U87 and U373) were hybridized to miR expression arrays and analyzed. Each cell type was engineered to express wild type EGFR (wtEGFR), dead kinase ∆EGFR (DK) or ∆EGFR at elevated levels similar to those observed in primary glioblastomas displaying EGFR overexpression. Parental cells expressing endogenous EGFR and wtEGFR cells stimulated with EGF for 1hr were also included in the analyses.
Project description:The aim of our study was to identify a microRNA signature for metastatic CRC that could predict and differentiate metastatic target organ localization. Normal and cancer tissues of three different groups of CRC patients were analyzed. RNA microarray and TaqMan Array analysis were performed on 66 italian patients with or without lymph nodes and/or liver recurrences. Data obtained with the two assays, were analyzed separately and then intersected to identify a primary CRC metastatic signature. Five differentially expressed microRNAs (hsa-miR-21, -103, -93, -31 and -566) were validated by qRT-PCR on a second group of 16 american metastatic patients. In situ hybridization was performed on the 16 american patients as well as on three distinct commercial tissues microarray (TMA), containing normal adjacent colon, the primary adenocarcinoma, normal and metastatic lymph nodes and liver. Hsa-microRNA-31,-21,-93, and-103 upregulation together with hsa-miR-566 downregulation defined the CRC metastatic signature, while in situ hybridization data identified a lymphonodal invasion profile. 33 patients had colon cancer with lymph nodes metastasis only (Any T, Any N, M0) and 15 were diagnosed with colon cancer, lymph nodes and liver metastases (Any T, Any N, M1). Separate tumor samples from the primary tumor, the metastatic lymph nodes and the liver metastasis were collected.
Project description:The EGF-receptor (EGFR) is amplified and mutated in glioblastoma (GBM) where its common mutation, (∆EGFR, also called EGFRvIII) has a variety of activities that promote growth and inhibit death, thereby conferring a strong tumor-enhancing effect. This range of activities suggested to us that ∆EGFR might exert its influence through pleiotropic effectors and we hypothesized that microRNAs (miRs) might serve such a function. To test this, we determined the miR profiles of GBM cells with activated wild type EGFR (wtEGFR) and mutant EGFR (∆EGFR) to cells with non-activated EGFR or kinase dead ∆EGFR.
Project description:The expression of human microRNAs in the cellular fraction of human peripheral blood of patients with diagnosed malignant mesotheliomas and asbestos-exposed controls. Altered expression of several miRNAs were observed for patients with diagnosed malignant mesotheliomas in comparison with asebstos-expsoed controls. The study group consists of 23 patients with diagnosed malignant mesothelioma (mean age 66 years, range 34 – 84 years). Patients were not treated with chemotherapy or radiation therapy before sample collection. The histological subtypes were: one sarcomatoid, seven biphasic, and twelve epithelioid cases. In three cases the histological subtype was unknown. The control group consists of 17 asbestos-exposed age-matched volunteers without any diagnosed cancer (mean age 68 years, range 47 – 80 years). Oligonucleotide microarrays were purchased from the Norwegican Microarray Consortium (www.microarray.no). The mirVana miRNA Probe Set v2.0 (Ambion) based on the miRBase Sequence Database v8.0. was used.
Project description:EGFRvIII is the most common deletion mutant of EGFR in human cancer and its levels are highly correlated with poor prognosis in GBM. The deletion of exons 2-7 removes most of the extracellular ligand binding domain, so it is unable to bind EGF or other EGFR-binding ligands. Nevertheless, the mutant receptor is constitutively phosphorylated, and is capable of activating downstream signaling pathways at a low level. To comprehensively identify the downstream signaling consequences of the EGFRvIII, we incorporated phosphoproteomic, transcription profiling and DNase-Seq data from U87MG glioblastoma cells expressing titrated levels of this mutant receptor. Total RNA were extracted from U87MG cells engineered to expressed different levels of EGFRvIII: medium (U87M; 1.5 million copies of EGFRvIII receptor per cell), high (U87H; 2 million copies per cell), super-high (U87SH; 2.5 million copies per cell), and kinase-dead EGFRvIII (U87DK; 2 million copies of kinase dead EGFRvIII per cell). RNA was hybridized to Affymetrix microarrays.
Project description:Although the oncogenic signalings driven by amplification and mutations of EGF receptor (EGFR) gene play a major role in glioblastoma pathogenesis, the responsible downstream mechanisms remain less clear. Here we demonstrate that tripartite motif-containing protein 59 (TRIM59), acting as a new downstream effector of EGFR signaling, regulates STAT3 activation in glioblastoma. EGFR signaling leads to TRIM59 upregulation through SOX9 that results in enhancing TRIM59 interaction with STAT3 in nucleus, and inhibiting STAT3 association with TC45 (the nuclear form of T cell protein tyrosine phosphatase TC-PTP), thereby maintaining STAT3 phosphorylation and activation and promoting tumorigenesis. Silencing TRIM59 suppresses cell proliferation, migration, and orthotopic xenograft brain tumorigenesis of GBM cells. Moreover, evaluation of GBM patient samples reveals an association among EGFR activation, TRIM59 expression, STAT3 phosphorylation, and poor prognoses. Our study identifies TRIM59 as a new regulator of oncogenic EGFR-STAT3 signaling and a potential therapeutic target for GBM patients with EGFR activation.
Project description:EGFRvIII is the most common deletion mutant of EGFR in human cancer and its levels are highly correlated with poor prognosis in GBM. The deletion of exons 2-7 removes most of the extracellular ligand binding domain, so it is unable to bind EGF or other EGFR-binding ligands. Nevertheless, the mutant receptor is constitutively phosphorylated, and is capable of activating downstream signaling pathways at a low level. To comprehensively identify the downstream signaling consequences of the EGFRvIII, we incorporated phosphoproteomic, transcription profiling and DNase-Seq data from U87MG glioblastoma cells expressing titrated levels of this mutant receptor.
Project description:Characterization of non-neoplastic and malignant human stem cell populations in their native state can provide new insights into gliomagenesis. Here we developed a purification strategy to directly isolate EGFR+/– populations from human germinal matrix (GM) and adult subventricular zone autopsy tissues, and from de-novo glioblastoma (GBM) resections, enriching for cells capable of binding EGF ligand (LBEGFR+), and uniquely compared their functional and molecular properties. LBEGFR+ populations in both GM and GBM encompassed all sphere-forming cells and displayed proliferative stem cell properties in vitro. In xenografts, LBEGFR+ GBM cells showed robust tumor initiation and progression to high-grade, infiltrative gliomas. Whole transcriptome sequencing analysis confirmed enrichment of proliferative pathways in both developing and neoplastic freshly isolated EGFR+ populations, and identified both unique and shared sets of genes. The ability to prospectively isolate stem cell populations using native ligand-binding ability opens new doors into understanding both normal human progenitors and tumor cell biology.
Project description:We profiles the effects of six protein phosphatase inhibitors on EGF-dependent phosphoproteome dynamics. The cells were treated with 20 nM EGF for 8 or 20 min with or without 15 min pre-treatment of one of the phosphatase inhibitors (100 nM or 1 M; Raphin1 acetate, sanguinarine chloride, KY-226, SHP099, NSC95397, or BCI). We further focused on sanguinarine chloride, and Hela cells were treated with 20 nM EGF for 3, 8, or 20min with or without 15 min pre-treatment of sanguinarine (5, 50, or 500 nM). We also examined combination of sanguinarine chloride (500 nM) and BIRB796 (500 nM), a p38-kinase inhibitor.
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:Epidermal growth factor receptor (EGFR)-driven signaling regulates fundamental cellular processes. Dysregulated signaling via EGFR is implicated in numerous disease pathologies, and distinct EGFR-associated disease etiologies are known to be tissue-specific. The molecular basis of this tissue specificity remains poorly understood. Most studies of EGFR signaling to date have been performed in vitro or in tissue-specific mouse models of disease, which has limited insight into EGFR signaling patterns in healthy tissues. Here, we carried out integrated phosphoproteomic, proteomic, and transcriptomic analyses of signaling changes across various mouse tissues in response to short-term stimulation with the Egfr ligand Egf. We show how both baseline and Egf-stimulated signaling behaviors differ between tissues. Moreover, we propose how baseline phosphorylation and total protein levels may be associated with clinically relevant tissue-specific Egfr-associated phenotypes. Altogether, our analyses illustrate tissue-specific effects of Egf stimulation and highlight potential links between underlying tissue biology and Egfr signaling output.