The TWEAK-Fn14 Ligand Receptor Axis Promotes Glioblastoma Cell Invasion and Survival Via Activation of Multiple GEF-Rho GTPase Signaling Systems Item Type text; Electronic Dissertation Authors Fortin Ensign, Shannon Patricia Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 07/10/2021 15:22:11 Link to Item http://hdl.handle.net/10150/293463 THE TWEAK-FN14 LIGAND RECEPTOR AXIS PROMOTES GLIOBLASTOMA CELL INVASION AND SURVIVAL VIA ACTIVATION OF MULTIPLE GEF-RHO GTPASE SIGNALING SYSTEMS by Shannon Fortin Ensign _____________________________ Copyright © Shannon Fortin Ensign 2013 A Dissertation Submitted to the Faculty of the GRADUATE INTERDISCIPLINARY PROGRAM IN CANCER BIOLOGY In Partial Fulfillment of the Requirements For the Degree of DOCTOR OF PHILOSOPHY In the Graduate College THE UNIVERSITY OF ARIZONA 2013 2 THE UNIVERSITY OF ARIZONA GRADUATE COLLEGE As members of the Dissertation Committee, we certify that we have read the dissertation prepared by Shannon Fortin Ensign , titled The TWEAK-Fn14 Ligand Receptor Axis Promotes Glioblastoma Cell Invasion and Survival Via Activation of Multiple GEF-Rho GTPase Signaling Systems and recommend that it be accepted as fulfilling the dissertation requirement for the Degree of Doctor of Philosophy. _______________________________________________ Date: April 26, 2013 Nhan Tran, PhD _______________________________________________ Date: April 26, 2013 Suwon Kim, PhD _______________________________________________ Date: April 26, 2013 Jesse Martinez, PhD _______________________________________________ Date: April 26, 2013 Anne Cress, PhD _______________________________________________ Date: April 26, 2013 Maria Bishop, MD Final approval and acceptance of this dissertation is contingent upon the candidate’s submission of the final copies of the dissertation to the Graduate College. I hereby certify that I have read this dissertation prepared under my direction and recommend that it be accepted as fulfilling the dissertation requirement. ________________________________________________ Date: April 26, 2013 Dissertation Director: Nhan Tran, PhD ________________________________________________ Date: April 26, 2013 Dissertation Director: Suwon Kim, PhD 3 STATEMENT BY AUTHOR This dissertation has been submitted in partial fulfillment of the requirements for an advanced degree at the University of Arizona and is deposited in the University Library to be made available to borrowers under rules of the Library. Brief quotations from this dissertation are allowable without special permission, provided that accurate acknowledgment of source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the copyright holder. SIGNED: Shannon Fortin Ensign 4 ACKNOWLEDGEMENTS I would like to express my sincerest gratitude towards everyone who has helped me reach this stage in my career and path in life. I particularly would like to thank my mentor, Dr. Nhan Tran, for his support not only in my graduate studies but as a mentor to me in my undergraduate years as well. Your passion for science and teaching has inspired me to work hard to achieve my goals, and I truly appreciate your guidance, critiques, support and friendship. In addition, I would like to thank Dr. Michael Berens for his time and devotion also as a mentor during both my undergraduate and graduate studies. Your drive for success, caring personality, and remarkable ability for collaboration are inspirational. I hope to take what knowledge I have learned from these mentors and apply it to my own future career. I feel that both of these remarkable individuals keep paramount the understanding that so many patients are suffering from the disease of cancer and that there is an urgency and precision to our work as scientists. I will strive to follow in their lead and never lose sight of this most important aspect of research. I would also like to express my appreciation for the time and devotion of my committee members, Drs. Jesse Martinez, Anne Cress, Suwon Kim, and Maria Bishop. Thank you for sharing your resources, expertise, and critiques; I value your guidance both in my research and towards my personal future career. Thank you to the amazing and devoted undergraduate interns, Ian Mathews, Molly Kupfer, and Danielle Ennesser, who have worked with me during my dissertation. For me it has been so rewarding to mentor these future scientists, and so inspirational to witness their upmost enthusiasm for science and their desire to contribute towards a project in cancer research. I have learned so much in teaching, and these interactions have brought friendship and appreciation in cultivating their passions. I wish them all the best success for their future careers as researchers and clinicians to come. Thank you to the wonderful post-doctoral fellows with whom I have had the chance to work: Dr. Timothy Whitsett and Dr. Harshil Dhruv. Your friendship and guidance have been invaluable to me during my graduate studies and I have much gratitude for your mentorship, and for sharing your critiques and expertise with me. Thank you to everyone in the Berens and Tran labs for their friendship and support during my graduate research. Thank you to the Cancer Biology Interdisciplinary Graduate Program and to Anne Cione for always being so helpful in her assistance and for her genuine caring personality. Finally, I would like to express my deepest appreciation to my friends and family, whose love, support, and encouragement have been unwavering in all my years of education and who have made it possible for me to achieve my goals. 5 DEDICATION I would like to dedicate this dissertation to those all those individuals who have suffered from the illness of cancer, and to their family and friends who have endured this diagnosis with them. 6 TABLE OF CONTENTS LIST OF FIGURES ........................................................................................................ 11 LIST OF TABLES .......................................................................................................... 14 ABSTRACT ..................................................................................................................... 15 CHAPTER 1: INTRODUCTION .................................................................................. 17 Classification of brain tumors ................................................................................. 17 Clinical description and pathology of brain tumors ...................................... 17 The brain tumor microenvironment ............................................................... 20 Molecular classification and genetics of malignant gliomas ......................... 23 Epidemiology of malignant gliomas ....................................................................... 29 Current treatment strategies for glioblastoma ......................................................... 35 Mechanisms of glioma cell invasion ....................................................................... 39 RhoGTPase signaling .................................................................................... 40 Characteristics and regulation of RhoGTPases .................................... 40 Deregulation of RhoGTPase signaling in brain tumors ....................... 44 TWEAK-Fn14 signaling in glioblastoma ...................................................... 46 Statement of the problem ........................................................................................ 49 Hypotheses and Specific Aims ................................................................................ 50 CHAPTER 2: PRESENT STUDY ................................................................................. 52 REFERENCES ................................................................................................................ 56 7 TABLE OF CONTENTS - Continued APPENDIX A - CDC42 AND THE GUANINE NUCLEOTIDE EXCHANGE FACTORS ECT2 AND TRIO MEDIATE FN14-INDUCED MIGRATION AND INVASION OF GLIOBLASTOMA CELLS ............................................................... 78 Abstract ................................................................................................................... 78 Introduction ............................................................................................................. 79 Materials and Methods ............................................................................................ 81 Results ..................................................................................................................... 88 Ect2 binds to the Fn14 receptor and regulates TWEAK-stimulated Rac1 activation ........................................................................................................ 88 TWEAK regulation of Rac1 activation is dependent upon Cdc42 function . 88 Depletion of Cdc42 or Ect2 by siRNA suppresses TWEAK- or Fn14-induced cell migration and invasion ............................................................................ 91 Trio activates Rac1 downstream of Fn14 ...................................................... 94 Depletion of Rac1, Cdc42, Ect2, or Trio by siRNA suppresses TWEAK- induced