DOCSLIB.ORG

P-REX1 Creates a Positive Feedback Loop to Activate Growth Factor Receptor, PI3K/AKT and MEK/ERK Signaling in Breast Cancer

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
P-REX1 Creates a Positive Feedback Loop to Activate Growth Factor Receptor, PI3K/AKT and MEK/ERK Signaling in Breast Cancer Oncogene (2015) 34, 3968–3976 © 2015 Macmillan Publishers Limited All rights reserved 0950-9232/15 www.nature.com/onc ORIGINAL ARTICLE P-REX1 creates a positive feedback loop to activate growth factor receptor, PI3K/AKT and MEK/ERK signaling in breast cancer LM Dillon1, JR Bean1, W Yang1, K Shee1, LK Symonds1, JM Balko2,3, WH McDonald4, S Liu5,6, AM Gonzalez-Angulo5,6, GB Mills6, CL Arteaga2,3,7 and TW Miller1,8 Phosphatidylinositol 3-kinase (PI3K) promotes cancer cell survival, migration, growth and proliferation by generating phosphatidylinositol 3,4,5-trisphosphate (PIP3) in the inner leaflet of the plasma membrane. PIP3 recruits pleckstrin homology domain-containing proteins to the membrane to activate oncogenic signaling cascades. Anticancer therapeutics targeting the PI3K/AKT/mTOR (mammalian target of rapamycin) pathway are in clinical development. In a mass spectrometric screen to identify PIP3-regulated proteins in breast cancer cells, levels of the Rac activator PIP3-dependent Rac exchange factor-1 (P-REX1) increased in response to PI3K inhibition, and decreased upon loss of the PI3K antagonist phosphatase and tensin homolog (PTEN). P-REX1 mRNA and protein levels were positively correlated with ER expression, and inversely correlated with PI3K pathway activation in breast tumors as assessed by gene expression and phosphoproteomic analyses. P-REX1 increased activation of Rac1, PI3K/AKT and MEK/ERK signaling in a PTEN-independent manner, and promoted cell and tumor viability. Loss of P-REX1 or inhibition of Rac suppressed PI3K/AKT and MEK/ERK, and decreased viability. P-REX1 also promoted insulin-like growth factor-1 receptor activation, suggesting that P-REX1 provides positive feedback to activators upstream of PI3K. In support of a model where PIP3-driven P-REX1 promotes both PI3K/AKT and MEK/ERK signaling, high levels of P-REX1 mRNA (but not phospho-AKT or a transcriptomic signature of PI3K activation) were predictive of sensitivity to PI3K inhibitors among breast cancer cell lines. P-REX1 expression was highest in estrogen receptor-positive breast tumors compared with many other cancer subtypes, suggesting that neutralizing the P-REX1/Rac axis may provide a novel therapeutic approach to selectively abrogate oncogenic signaling in breast cancer cells. Oncogene (2015) 34, 3968–3976; doi:10.1038/onc.2014.328; published online 6 October 2014 INTRODUCTION the tumor suppressor phosphatase and tensin homolog (PTEN) 4 The phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of antagonizes PI3K by dephosphorylating PIP3. PIP3 recruits AKT rapamycin (mTOR) pathway is the most commonly aberrantly and other pleckstrin homology (PH) domain-containing proteins activated pathway in human cancer, promoting cell growth, to the membrane to promote their interaction and initiate migration, survival and proliferation. Genes encoding proteins in signaling cascades. this pathway are mutated in 470% of breast cancers, and In a proteomic screen to identify PIP3-regulated proteins pathway activation has been linked with resistance to anti- as effectors and markers of PI3K activation in breast cancer cells, estrogen and anti-HER2 therapies in estrogen receptor α-positive we found that the levels of PIP3-dependent Rac exchange (ER+) and HER2-positive breast cancers, respectively.1 PI3K factor-1 (P-REX1) were inversely correlated with PI3K activation. pathway-targeted therapeutics are in clinical development. Class This association was confirmed in human breast tumors. P-REX1 IA PI3Ks are activated by receptor tyrosine kinases such as was most highly expressed in estrogen receptor-positive (ER+) members of the epidermal growth factor receptor family (EGFR, breast cancer compared with various other cancer subtypes, and HER3) and the insulin receptor family (InsR, insulin-like growth P-REX1 mRNA levels were predictive of sensitivity to PI3K factor-1 (IGF-1) receptor, IGF-1R), as well as by Gβγ subunits inhibition. We also found that P-REX1 activates IGF-1R/InsR, released from activated G-protein-coupled receptors (GPCRs).2 Rac1, PI3K/AKT and MEK/ERK signaling, and promotes cell and PI3K phosphorylates phosphatidylinositol (4,5)-bisphosphate in tumor viability. These findings place P-REX1 both downstream and the inner leaflet of the plasma membrane to yield phosphatidy- upstream of PI3K, suggesting that P-REX1 is a key component of a 3 linositol (3,4,5)-trisphosphate (PIP3). Lipid phosphatase activity of positive feedback loop that drives oncogenic signaling. 1Department of Pharmacology and Toxicology, Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA; 2Department of Medicine, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN, USA; 3Breast Cancer Research Program, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN, USA; 4Proteomics Laboratory, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN, USA; 5Department of Breast Medical Oncology, MD Anderson Cancer Center, University of Texas, Houston, TX, USA ; 6Department of Systems Biology, MD Anderson Cancer Center, University of Texas, Houston, TX, USA; 7Department of Cancer Biology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN, USA and 8Comprehensive Breast Cancer Program, Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, NH, USA. Correspondence: Dr TW Miller, Department of Pharmacology and Toxicology, Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Dartmouth-Hitchcock Medical Center, One Medical Center Drive HB-7936, Lebanon, NH 03756, USA. E-mail: [email protected] Received 7 June 2014; revised 7 August 2014; accepted 13 August 2014; published online 6 October 2014 P-REX1 creates a positive feedback loop LM Dillon et al 3969 RESULTS was found to bind PTEN,10 we considered that PTEN may bind and PI3K activity regulates P-REX1 expression stabilize P-REX1. However, we detected only very low levels of P-REX1/PTEN interaction in cells (data not shown). Treatment with We performed a mass spectrometry (MS)-based proteomic screen to 11 identify proteins modulated by PI3K pathway activity in breast the pan-PI3K inhibitor GDC-0941 similarly increased P-REX1 cancer cells. MCF-7 cells stably expressing short hairpin RNA levels in parental MCF-7 and T47D cells, whereas AKT inhibition targeting PTEN (shPTEN) or short hairpin mismatch control (shMM) with MK-2206 did not (Figure 1e). Thus, P-REX1 levels are were treated with or without the pan-PI3K inhibitor BKM-1205 for modulated downstream of PI3K, but independently of AKT. 16 h. Lysates were analyzed by multidimensional protein identifica- We also explored whether PI3K activity modulates P-REX1 gene tion technology coupled with tandem mass spectrometry. Proteins expression. PI3K inhibition for 4 or 24 h increased P-REX1 mRNA exhibiting altered abundance in response to PI3K inhibition and/or levels in MCF-7 cells (Supplementary Figures S1A and B). Mining of PTEN knockdown are listed in Supplementary Table S1. Comparing prior gene expression microarray data from isogenic MCF-7/ the lists of proteins altered ⩾ 1.5-fold in abundance, we identified shPTEN, T47D/shPTEN and MDA-MB-361/shPTEN cells compared with respective shMM controls12 revealed that P-REX1 mRNA P-REX1 as a protein downregulated by PTEN knockdown (which fi activates PI3K) and upregulated by PI3K inhibition (Figures 1a and b). levels were signi cantly downregulated in all shPTEN lines. In P-REX1 is a guanine exchange factor (GEF) that integrates inputs addition, PI3K inhibition increased P-REX1 protein levels in cells from GPCRs via Gβγ, and from receptor tyrosine kinases and GPCRs pre-treated with the translation inhibitor cycloheximide 6 (Supplementary Figure S1C). These data suggest that P-REX1 via PIP3 to activate the Rho family GTPases Rac1/2/3. Given that P-REX1 was previously implicated in prostate cancer metastasis7 and levels are modulated by PI3K signaling at the transcriptional and 8,9 posttranslational levels: PIP -mediated activation of P-REX1 may shown to promote oncogenic signaling, we further investigated its 3 induce P-REX1 protein turnover as a form of negative feedback, role in PI3K signaling in breast cancer. and PI3K inhibition blocks negative feedback to induce transcrip- We validated MS results by immunoblotting of lysates from tion of genes encoding proteins that activate and transduce PI3K breast cancer cells treated with inhibitors of PI3K or AKT. MCF-7/ signaling (for example, ERBB3, IGF-1R,13 TSC114 and PREX1). shMM and T47D/shMM cells treated with 1 μM BKM-120 showed reduced p-AKT and increased P-REX1 protein levels over time (Figures 1c and d). The reason that P-REX1 levels did not increase Tumor levels of P-REX1 are inversely correlated with PI3K/AKT/ as markedly in shPTEN cells compared with shMM cells upon PI3K mTOR pathway activation, and positively correlated with ER inhibition is unclear but may be due in part to residual PIP3 in expression in breast tumors shPTEN cells, as evidenced by residual p-AKT in BKM-120-treated As PI3K activity modulates P-REX1 levels in breast cancer cells, we T47D/shPTEN cells (Figure 1d). As the P-REX1 homolog P-REX2a explored this relationship in human tumors. Using reverse-phase Figure 1. P-REX1 levels decrease upon PTEN-loss and increase with PI3K inhibition. (a) Summary of results from MS-based proteomic screen in MCF-7 cells (red asterisk
Load more

Recommended publications
  • PREX1 Polyclonal Antibody
    PREX1 Polyclonal Antibody Catalog No : YN1041 Reactivity : Human,Mouse Applications : WB,ELISA Gene Name : PREX1 KIAA1415 Protein Name : Phosphatidylinositol 3,4,5-trisphosphate-dependent Rac exchanger 1 protein (P- Rex1) (PtdIns(3,4,5)-dependent Rac exchanger 1) Human Gene Id : 57580 Human Swiss Prot Q8TCU6 No : Mouse Swiss Prot Q69ZK0 No : Immunogen : Synthesized peptide derived from human protein . at AA range: 340-420 Specificity : PREX1 Polyclonal Antibody detects endogenous levels of protein. Formulation : Liquid in PBS containing 50% glycerol, and 0.02% sodium azide. Source : Rabbit Dilution : WB 1:500-2000 ELISA 1:5000-20000 Purification : The antibody was affinity-purified from rabbit antiserum by affinity- chromatography using epitope-specific immunogen. Concentration : 1 mg/ml Storage Stability : -20°C/1 year Observed Band : 182 Cell Pathway : Chemokine, 1 / 2 Background : phosphatidylinositol-3,4,5-trisphosphate dependent Rac exchange factor 1(PREX1) Homo sapiens The protein encoded by this gene acts as a guanine nucleotide exchange factor for the RHO family of small GTP-binding proteins (RACs). It has been shown to bind to and activate RAC1 by exchanging bound GDP for free GTP. The encoded protein, which is found mainly in the cytoplasm, is activated by phosphatidylinositol-3,4,5-trisphosphate and the beta-gamma subunits of heterotrimeric G proteins. [provided by RefSeq, Jul 2008], Function : function:Functions as a RAC guanine nucleotide exchange factor (GEF), which activates the Rac proteins by exchanging bound GDP for free GTP. Its activity is synergistically activated by phosphatidylinositol-3,4,5-triphosphate and the beta gamma subunits of heterotrimeric G protein. May function downstream of heterotrimeric G proteins in neutrophils.,similarity:Contains 1 DEP domain.,similarity:Contains 1 DH (DBL-homology) domain.,similarity:Contains 1 PDZ (DHR) domain.,similarity:Contains 2 PH domains.,subcellular location:Mainly cytosolic.
    [Show full text]
  • Truncating PREX2 Mutations Activate Its GEF Activity and Alter Gene
    Truncating PREX2 mutations activate its GEF activity PNAS PLUS and alter gene expression regulation in NRAS-mutant melanoma Yonathan Lissanu Deribea,1,2, Yanxia Shia,b,1, Kunal Raia, Luigi Nezia, Samir B. Amina, Chia-Chin Wua, Kadir C. Akdemira, Mozhdeh Mahdavia, Qian Penga, Qing Edward Changc, Kirsti Hornigoldd, Stefan T. Arolde, Heidi C. E. Welchd, Levi A. Garrawayf,g, and Lynda China,c,2 aDepartment of Genomic Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX 77030; bSun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborate Center for Cancer Medicine, Guangzhou 510060, China; cInstitute for Applied Cancer Science (IACS), The University of Texas MD Anderson Cancer Center, Houston, TX 77030; dThe Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, United Kingdom; eDivision of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900 Saudi Arabia; fDepartment of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215; and gBroad Institute of MIT and Harvard, Boston, MA 02141 Edited by Dennis A. Carson, University of California at San Diego, La Jolla, CA, and approved January 26, 2016 (received for review July 14, 2015) PREX2 (phosphatidylinositol-3,4,5-triphosphate-dependent Rac- To date, the most obvious connection between PREX2 and exchange factor 2) is a PTEN (phosphatase and tensin homolog cancer relevant pathways is through its physical interaction with deleted on chromosome 10) binding protein that is significantly PTEN (7). PTEN catalyzes the conversion of phosphatidylino- mutated in cutaneous melanoma and pancreatic ductal adenocar- sitol-3,4,5-trisphosphate to phosphatidylinositol-4,5 bisphosphate.
    [Show full text]
  • IGF1R Deficiency Attenuates Acute Inflammatory Response in A
    www.nature.com/scientificreports OPEN IGF1R deficiency attenuates acute inflammatory response in a bleomycin-induced lung injury Received: 7 November 2016 Accepted: 17 May 2017 mouse model Published: xx xx xxxx Sergio Piñeiro-Hermida1, Icíar P. López1, Elvira Alfaro-Arnedo1, Raquel Torrens1, María Iñiguez2, Lydia Alvarez-Erviti3, Carlos Ruíz-Martínez4 & José G. Pichel 1 IGF1R (Insulin-like Growth Factor 1 Receptor) is a tyrosine kinase with pleiotropic cellular functions. IGF activity maintains human lung homeostasis and is implicated in pulmonary diseases such as cancer, ARDS, COPD, asthma and fibrosis. Here we report that lung transcriptome analysis in mice with a postnatally-induced Igf1r gene deletion showed differentially expressed genes with potentially protective roles related to epigenetics, redox and oxidative stress. After bleomycin-induced lung injury, IGF1R-deficient mice demonstrated improved survival within a week. Three days post injury, IGF1R- deficient lungs displayed changes in expression of IGF system-related genes and reduced vascular fragility and permeability. Mutant lungs presented reduced inflamed area, down-regulation of pro- inflammatory markers and up-regulation of resolution indicators. Decreased inflammatory cell presence in BALF was reflected in diminished lung infiltration mainly affecting neutrophils, also corroborated by reduced neutrophil numbers in bone marrow, as well as reduced lymphocyte and alveolar macrophage counts. Additionally, increased SFTPC expression together with hindered HIF1A expression and augmented levels of Gpx8 indicate that IGF1R deficiency protects against alveolar damage. These findings identify IGF1R as an important player in murine acute lung inflammation, suggesting that targeting IGF1R may counteract the inflammatory component of many lung diseases. Inflammation is a relevant component of many lung diseases including ARDS, COPD, asthma, cancer, fibrosis and pneumonia1–5.
    [Show full text]
  • Functional Dependency Analysis Identifies Potential Druggable
    cancers Article Functional Dependency Analysis Identifies Potential Druggable Targets in Acute Myeloid Leukemia 1, 1, 2 3 Yujia Zhou y , Gregory P. Takacs y , Jatinder K. Lamba , Christopher Vulpe and Christopher R. Cogle 1,* 1 Division of Hematology and Oncology, Department of Medicine, College of Medicine, University of Florida, Gainesville, FL 32610-0278, USA; yzhou1996@ufl.edu (Y.Z.); gtakacs@ufl.edu (G.P.T.) 2 Department of Pharmacotherapy and Translational Research, College of Pharmacy, University of Florida, Gainesville, FL 32610-0278, USA; [email protected]fl.edu 3 Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610-0278, USA; cvulpe@ufl.edu * Correspondence: [email protected]fl.edu; Tel.: +1-(352)-273-7493; Fax: +1-(352)-273-5006 Authors contributed equally. y Received: 3 November 2020; Accepted: 7 December 2020; Published: 10 December 2020 Simple Summary: New drugs are needed for treating acute myeloid leukemia (AML). We analyzed data from genome-edited leukemia cells to identify druggable targets. These targets were necessary for AML cell survival and had favorable binding sites for drug development. Two lists of genes are provided for target validation, drug discovery, and drug development. The deKO list contains gene-targets with existing compounds in development. The disKO list contains gene-targets without existing compounds yet and represent novel targets for drug discovery. Abstract: Refractory disease is a major challenge in treating patients with acute myeloid leukemia (AML). Whereas the armamentarium has expanded in the past few years for treating AML, long-term survival outcomes have yet to be proven. To further expand the arsenal for treating AML, we searched for druggable gene targets in AML by analyzing screening data from a lentiviral-based genome-wide pooled CRISPR-Cas9 library and gene knockout (KO) dependency scores in 15 AML cell lines (HEL, MV411, OCIAML2, THP1, NOMO1, EOL1, KASUMI1, NB4, OCIAML3, MOLM13, TF1, U937, F36P, AML193, P31FUJ).
    [Show full text]
  • Rho Family Gtpases and Rho Gefs in Glucose Homeostasis
    cells Review Rho Family GTPases and Rho GEFs in Glucose Homeostasis Polly A. Machin 1, Elpida Tsonou 1,2, David C. Hornigold 2 and Heidi C. E. Welch 1,* 1 Signalling Programme, The Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK; [email protected] (P.A.M.); [email protected] (E.T.) 2 Bioscience Metabolism, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Cambridge CB22 3AT, UK; [email protected] * Correspondence: [email protected]; Tel.: +44-(0)1223-496-596 Abstract: Dysregulation of glucose homeostasis leading to metabolic syndrome and type 2 diabetes is the cause of an increasing world health crisis. New intriguing roles have emerged for Rho family GTPases and their Rho guanine nucleotide exchange factor (GEF) activators in the regulation of glucose homeostasis. This review summates the current knowledge, focusing in particular on the roles of Rho GEFs in the processes of glucose-stimulated insulin secretion by pancreatic β cells and insulin-stimulated glucose uptake into skeletal muscle and adipose tissues. We discuss the ten Rho GEFs that are known so far to regulate glucose homeostasis, nine of which are in mammals, and one is in yeast. Among the mammalian Rho GEFs, P-Rex1, Vav2, Vav3, Tiam1, Kalirin and Plekhg4 were shown to mediate the insulin-stimulated translocation of the glucose transporter GLUT4 to the plasma membrane and/or insulin-stimulated glucose uptake in skeletal muscle or adipose tissue. The Rho GEFs P-Rex1, Vav2, Tiam1 and β-PIX were found to control the glucose-stimulated release of insulin by pancreatic β cells.
    [Show full text]
  • ERK/MAPK Signaling Drives Overexpression of the Rac-GEF, PREX1, in BRAF- and NRAS-Mutant Melanoma
    HHS Public Access Author manuscript Author ManuscriptAuthor Manuscript Author Mol Cancer Manuscript Author Res. Author Manuscript Author manuscript; available in PMC 2017 October 01. Published in final edited form as: Mol Cancer Res. 2016 October ; 14(10): 1009–1018. doi:10.1158/1541-7786.MCR-16-0184. ERK/MAPK Signaling Drives Overexpression of the Rac-GEF, PREX1, in BRAF- and NRAS-mutant Melanoma Meagan B. Ryan1, Alexander J. Finn2, Katherine H. Pedone4, Nancy E. Thomas2, Channing J. Der1,4,*, and Adrienne D. Cox1,3,4,* 1Department of Pharmacology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 2Department of Dermatology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 3Department of Radiation Oncology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 4Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina Abstract Recently we identified that PREX1 overexpression is critical for metastatic but not tumorigenic growth in a mouse model of NRAS-driven melanoma. In addition, a PREX1 gene signature correlated with and was dependent on ERK mitogen-activated protein kinase (MAPK) activation in human melanoma cell lines. In the current study, the underlying mechanism of PREX1 overexpression in human melanoma was assessed. PREX1 protein levels were increased in melanoma tumor tissues and cell lines compared with benign nevi and normal melanocytes, respectively. Suppression of PREX1 by siRNA impaired invasion but not proliferation in vitro. PREX1-dependent invasion was attributable to PREX1-mediated activation of the small GTPase RAC1 but not the related small GTPase CDC42.
    [Show full text]
  • 13168 PREX1 (D8O8D) Rabbit Mab
    Revision 1 C 0 2 - t PREX1 (D8O8D) Rabbit mAb a e r o t S Orders: 877-616-CELL (2355) [email protected] 8 Support: 877-678-TECH (8324) 6 1 Web: [email protected] 3 www.cellsignal.com 1 # 3 Trask Lane Danvers Massachusetts 01923 USA For Research Use Only. Not For Use In Diagnostic Procedures. Applications: Reactivity: Sensitivity: MW (kDa): Source/Isotype: UniProt ID: Entrez-Gene Id: WB, IF-IC H Mk Endogenous 190, 110 Rabbit IgG Q8TCU6 57580 Product Usage Information poor survival (15). Additional research studies suggest that PREX Rac-GEF activity is enhanced by phosphorylation in response to growth factors or hormones, and may require Application Dilution coincident dephosphorylation of two PH domain serine residues. The upstream kinases and precise regulatory mechanism remains elusive (15,17). Western Blotting 1:1000 1. Welch, H.C. et al. (2002) Cell 108, 809-21. Immunofluorescence (Immunocytochemistry) 1:400 2. Hill, K. et al. (2005) J Biol Chem 280, 4166-73. 3. Mayeenuddin, L.H. and Garrison, J.C. (2006) J Biol Chem 281, 1921-8. 4. Barber, M.A. et al. (2007) J Biol Chem 282, 29967-76. Storage 5. Welch, H.C. et al. (2005) Curr Biol 15, 1867-73. Supplied in 10 mM sodium HEPES (pH 7.5), 150 mM NaCl, 100 µg/ml BSA, 50% 6. Dong, X. et al. (2005) Curr Biol 15, 1874-9. glycerol and less than 0.02% sodium azide. Store at –20°C. Do not aliquot the antibody. 7. Zhao, T. et al. (2007) J Leukoc Biol 81, 1127-36.
    [Show full text]
  • PREX1 Integrates G Protein-Coupled Receptor and Phosphoinositide 3-Kinase Signaling to Promote Glioblastoma Invasion
    www.impactjournals.com/oncotarget/ Oncotarget, 2017, Vol. 8, (No. 5), pp: 8559-8573 Research Paper PREX1 integrates G protein-coupled receptor and phosphoinositide 3-kinase signaling to promote glioblastoma invasion Alexander Gont1,2, Manijeh Daneshmand1,3, John Woulfe1,3, Sylvie J. Lavictoire1, Ian A.J. Lorimer1,2,4 1Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Canada 2Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada 3Department of Pathology and Laboratory Medicine, University of Ottawa, Ottawa, Ontario, Canada 4Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada Correspondence to: Ian A.J. Lorimer, email: [email protected] Keywords: glioma, glioblastoma, invasion, PREX1, dopamine receptor Abbreviations: GEF, guanine nucleotide exchange factor Received: September 01, 2016 Accepted: December 06, 2016 Published: December 29, 2016 ABSTRACT A defining feature of the brain cancer glioblastoma is its highly invasive nature. When glioblastoma cells are isolated from patients using serum free conditions, they accurately recapitulate this invasive behaviour in animal models. The Rac subclass of Rho GTPases has been shown to promote invasive behaviour in glioblastoma cells isolated in this manner. However the guanine nucleotide exchange factors responsible for activating Rac in this context have not been characterized previously. PREX1 is a Rac guanine nucleotide exchange factor that is synergistically activated by binding of G protein bg subunits and the phosphoinositide 3-kinase pathway second messenger phosphatidylinositol 3,4,5 trisphosphate. This makes it of particular interest in glioblastoma, as the phosphoinositide 3-kinase pathway is aberrantly activated by mutation in almost all cases. We show that PREX1 is expressed in glioblastoma cells isolated under serum-free conditions and in patient biopsies.
    [Show full text]
  • Table S1. 103 Ferroptosis-Related Genes Retrieved from the Genecards
    Table S1. 103 ferroptosis-related genes retrieved from the GeneCards. Gene Symbol Description Category GPX4 Glutathione Peroxidase 4 Protein Coding AIFM2 Apoptosis Inducing Factor Mitochondria Associated 2 Protein Coding TP53 Tumor Protein P53 Protein Coding ACSL4 Acyl-CoA Synthetase Long Chain Family Member 4 Protein Coding SLC7A11 Solute Carrier Family 7 Member 11 Protein Coding VDAC2 Voltage Dependent Anion Channel 2 Protein Coding VDAC3 Voltage Dependent Anion Channel 3 Protein Coding ATG5 Autophagy Related 5 Protein Coding ATG7 Autophagy Related 7 Protein Coding NCOA4 Nuclear Receptor Coactivator 4 Protein Coding HMOX1 Heme Oxygenase 1 Protein Coding SLC3A2 Solute Carrier Family 3 Member 2 Protein Coding ALOX15 Arachidonate 15-Lipoxygenase Protein Coding BECN1 Beclin 1 Protein Coding PRKAA1 Protein Kinase AMP-Activated Catalytic Subunit Alpha 1 Protein Coding SAT1 Spermidine/Spermine N1-Acetyltransferase 1 Protein Coding NF2 Neurofibromin 2 Protein Coding YAP1 Yes1 Associated Transcriptional Regulator Protein Coding FTH1 Ferritin Heavy Chain 1 Protein Coding TF Transferrin Protein Coding TFRC Transferrin Receptor Protein Coding FTL Ferritin Light Chain Protein Coding CYBB Cytochrome B-245 Beta Chain Protein Coding GSS Glutathione Synthetase Protein Coding CP Ceruloplasmin Protein Coding PRNP Prion Protein Protein Coding SLC11A2 Solute Carrier Family 11 Member 2 Protein Coding SLC40A1 Solute Carrier Family 40 Member 1 Protein Coding STEAP3 STEAP3 Metalloreductase Protein Coding ACSL1 Acyl-CoA Synthetase Long Chain Family Member 1 Protein
    [Show full text]
  • Rho Gtpase Regulators and Effectors in Autism Spectrum Disorders
    cells Review Rho GTPase Regulators and Effectors in Autism Spectrum Disorders: Animal Models and Insights for Therapeutics Daji Guo , Xiaoman Yang and Lei Shi * JNU-HKUST Joint Laboratory for Neuroscience and Innovative Drug Research, College of Pharmacy, Jinan University, Guangzhou 510632, China; [email protected] (D.G.); [email protected] (X.Y.) * Correspondence: [email protected] or [email protected]; Tel.: +86-020-85222120 Received: 26 February 2020; Accepted: 26 March 2020; Published: 31 March 2020 Abstract: The Rho family GTPases are small G proteins that act as molecular switches shuttling between active and inactive forms. Rho GTPases are regulated by two classes of regulatory proteins, guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). Rho GTPases transduce the upstream signals to downstream effectors, thus regulating diverse cellular processes, such as growth, migration, adhesion, and differentiation. In particular, Rho GTPases play essential roles in regulating neuronal morphology and function. Recent evidence suggests that dysfunction of Rho GTPase signaling contributes substantially to the pathogenesis of autism spectrum disorder (ASD). It has been found that 20 genes encoding Rho GTPase regulators and effectors are listed as ASD risk genes by Simons foundation autism research initiative (SFARI). This review summarizes the clinical evidence, protein structure, and protein expression pattern of these 20 genes. Moreover, ASD-related behavioral phenotypes in animal models of these genes are reviewed, and the therapeutic approaches that show successful treatment effects in these animal models are discussed. Keywords: Rho GTPase; autism spectrum disorder; guanine nuclear exchange factor; GTPase-activating protein; animal model; behavior 1.
    [Show full text]
  • P-REX2, a Novel PI-3-Kinase Sensitive Rac Exchange Factor
    FEBS 28675 FEBS Letters 572 (2004) 167–171 P-REX2, a novel PI-3-kinase sensitive Rac exchange factor Hans Rosenfeldta, JoseVazquez-Prado b, J. Silvio Gutkinda,* aOral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, DHHS, Bethesda, MD 20892-4330, USA bDepartment of Pharmacology, CINVESTAV-IPN Av. Instituto Politecnico Nacional 2508 Col. San Pedro Zacatenco, 07360 Apartado postal 14-740, 07000 Mexico, D.F. Mexico Received 4 June 2004; accepted 22 June 2004 Available online 22 July 2004 Edited by Richard Marais domains, but contains a much shorter C-terminus. P-REX2 Abstract We have identified an activator of Rac, P-REX2, that is structurally related to the exchange factor PtdIns(3,4,5)- overexpression stimulated Rac- and Cdc42-GTP loading, and dependent Rac exchanger (P-REX1), but exhibits distinct tissue- serum response element (SRE) dependent transcription. specific expression. P-REX2 is spliced into two RNA species, Moreover, P-REX2 activation of Rac and the SRE was further 3.5 and 10 kb in size. The cDNA corresponding to the stimulated by PI-3 kinase, suggesting that P-REX2 may smaller transcript encodes a protein that exhibits strong simi- function as part of a tissue-specific mechanism by which larity with P-REX1 within its N-terminal domains, but differs in polypeptide growth factors and G protein-coupled receptors the C-terminal region. P-REX2 promoted increased levels of (GPCRs) regulate small GTPases. GTP-bound Rac that could be further stimulated by enhancing PI-3K activity. Thus, P-REX2 may serve as a novel link between Rac activation and the PI-3 kinase pathway.
    [Show full text]
  • Uncovering the Genomic Architecture of Gene Fusions Ken Chen University of Texas M.D
    Washington University School of Medicine Digital Commons@Becker Open Access Publications 2013 BreakTrans: Uncovering the genomic architecture of gene fusions Ken Chen University of Texas M.D. Anderson Cancer Center Nicholas E. Navin University of Texas M.D. Anderson Cancer Center Yong Wang University of Texas M.D. Anderson Cancer Center Heather K. Schmidt Washington University School of Medicine in St. Louis John W. Wallis Washington University School of Medicine in St. Louis See next page for additional authors Follow this and additional works at: https://digitalcommons.wustl.edu/open_access_pubs Recommended Citation Chen, Ken; Navin, Nicholas E.; Wang, Yong; Schmidt, Heather K.; Wallis, John W.; Niu, Beifang; Fan, Xian; Zhao, Hao; McLellan, Michael D.; Hoadley, Katherine A.; Mardis, Elaine R.; Ley, Timothy J.; Perou, Charles M.; Wilson, Richard K.; and Ding, Li, ,"BreakTrans: Uncovering the genomic architecture of gene fusions." Genome Biology.14,8. R87. (2013). https://digitalcommons.wustl.edu/open_access_pubs/1849 This Open Access Publication is brought to you for free and open access by Digital Commons@Becker. It has been accepted for inclusion in Open Access Publications by an authorized administrator of Digital Commons@Becker. For more information, please contact [email protected]. Authors Ken Chen, Nicholas E. Navin, Yong Wang, Heather K. Schmidt, John W. Wallis, Beifang Niu, Xian Fan, Hao Zhao, Michael D. McLellan, Katherine A. Hoadley, Elaine R. Mardis, Timothy J. Ley, Charles M. Perou, Richard K. Wilson, and Li Ding This open
    [Show full text]