GSK3B Regulates Epithelial-Mesenchymal Transition and Cancer Stem Cell Properties and Is a Novel Drug Target for Triple-Negative Breast Cancer
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The Texas Medical Center Library DigitalCommons@TMC The University of Texas MD Anderson Cancer Center UTHealth Graduate School of The University of Texas MD Anderson Cancer Biomedical Sciences Dissertations and Theses Center UTHealth Graduate School of (Open Access) Biomedical Sciences 8-2017 GSK3B regulates epithelial-mesenchymal transition and cancer stem cell properties and is a novel drug target for triple-negative breast cancer Geraldine Vidhya Raja Follow this and additional works at: https://digitalcommons.library.tmc.edu/utgsbs_dissertations Part of the Life Sciences Commons, and the Medicine and Health Sciences Commons Recommended Citation Raja, Geraldine Vidhya, "GSK3B regulates epithelial-mesenchymal transition and cancer stem cell properties and is a novel drug target for triple-negative breast cancer" (2017). The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences Dissertations and Theses (Open Access). 806. https://digitalcommons.library.tmc.edu/utgsbs_dissertations/806 This Dissertation (PhD) is brought to you for free and open access by the The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences at DigitalCommons@TMC. It has been accepted for inclusion in The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences Dissertations and Theses (Open Access) by an authorized administrator of DigitalCommons@TMC. For more information, please contact [email protected]. GSK3β REGULATES EPITHELIAL-MESENCHYMAL TRANSITION AND CANCER STEM CELL PROPERTIES AND IS A NOVEL DRUG TARGET FOR TRIPLE-NEGATIVE BREAST CANCER. by Geraldine Vidhya Raja, MS. APPROVED: ______________________________ Sendurai Mani, Ph.D. Advisory Professor ______________________________ Joya Chandra, Ph.D. ______________________________ Jonathan Kurie, MD. ______________________________ Zahid Siddik, Ph.D. ______________________________ Rama Soundararajan, Ph.D. APPROVED: ___________________________ Dean, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences i GSK3β REGULATES EPITHELIAL-MESENCHYMAL TRANSITION AND CANCER STEM CELL PROPERTIES AND IS A NOVEL DRUG TARGET FOR TRIPLE-NEGATIVE BREAST CANCER. A DISSERTATION Presented to the Faculty of The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY by Geraldine Vidhya Raja, MS. Houston, Texas August, 2017 ii Dedicated to my husband who has been my pillar of support, for his unwavering faith in me even when I did not and for seeing me through all my frustrations and without whom I could not have withstood the rigors of Ph.D. iii Acknowledgement After I finished my Masters, I knew Ph.D. was the natural next step in my career but little did I know that Ph.D. is not a step but a journey. Now that the end is in sight, I would like to take a moment to express my gratitude to all the people who have guided, and supported me and served as beacons of hope throughout this journey. First and foremost, I would like to express my deepest gratitude to my mentor, Dr. Sendurai Mani, who gave me the opportunity to work in his lab and on his projects. He was always there whenever I needed him. He has been a very understanding and supportive mentor throughout my Ph.D. and I really appreciate all that he has done for me. I would also like to thank my committee members, Dr. Joya Chandra, Dr. Rama Soundararajan, Dr. Elsa Flores, Dr. Jonathan Kurie and Dr. Zahid Siddik for their constant guidance and support. Next, I would like to convey my vote of thanks to my lab family. Each and every lab member has been instrumental in making my time in Mani Lab a wonderful and memorable one. A special thanks to Dr. Petra Den Hollander and Dr. Rama Soundararajan for reading and editing my thesis and for being my scientific and career advisors. I would also like to extend my thanks to all the post-docs in the lab, present and past, Dr. Joseph Taube, Dr. Tapasree Roysarkar, Dr. Mike Pietila, Dr. Anurag Paranjape, Dr. Jenaro Garcia-Huidobro and Dr. Robiya Joseph for their guidance and support. I also have a very close friend in Esmeralda Ramirez-Pena who has been a wonderful companion as we navigated through Ph.D. together. Ms. Neeraja Bhangre, Dr. Rebeca Romero Aburto, Ms. Vinita Shivakumar, Ms. Yvette Gonzales, Dr. Saradhi Mallampati and Dr. Nathalie Sphyris have all an been integral part of this journey. Also a special thanks to Ms. Barbara Sadeghi who has been a very gracious and helpful person, always greeting me with iv a smile and helping me whatever was needed. I really appreciate ITERT for being so student oriented and going out of the way to help trainees forge a career. I would also like to take this opportunity to thank Dr. Jeffrey Chang, who is an excellent teacher and very patient with me while I tried my hand at Bioinformatics. It has been an honor and pride, being a part of GSBS and the cancer biology program. I am grateful to Ms. Bunny Perez, Ms. Joy Lademora and Ms. Lily Agustino for their constant support and guidance. I would like to thank the school for admitting me and making my dream come true. Finally, my wonderful family has stood by me, supported me and tolerated me through all these years and their love for me has been by driving force. A heartfelt thank you to all my friends at UT housing, who were with me when I need anything and are our family away from home. Without them and my precious labmates, I could not have survived living alone with a kid. So just like you need a village to bring up a baby, you need a whole world to nurture a doctoral candidate. Indeed I am blessed to have a whole loving community looking out for me and helping me realize my dreams and all I can say in return is THANK YOU from the bottom of my heart!!! God bless you all for all that you have done for me! v Abstract GSK3β regulates Epithelial-Mesenchymal-Transition and Cancer Stem Cell properties and is a novel drug target for Triple-Negative Breast Cancer. Geraldine Vidhya Raja, MS. Advisory Professor: Sendurai Mani, Ph.D. Triple-Negative breast cancers (TNBCs) are highly aggressive and lack the expression of Estrogen Receptor (ER), Progesterone Receptor (PR) as well as Human Epidermal Growth Factor Receptor (HER2). Consequently, patients diagnosed with TNBCs have poor overall- and disease-free survival rates compared to other subtypes of breast cancer due to lack of targeted therapies as well as de novo or acquired chemoresistance, disease recurrence, and lack of targeted therapy. Hence it is critical to identify novel targets to treat TNBCs. TNBCs are characterized by the presence of mesenchymal-like cells, which is indicative that EMT (epithelial- mesenchymal-transition) plays an important role in the progression of this disease. EMT has also been implicated in chemoresistance, tumor recurrence and generation of cancer stem cells (CSCs). The Wnt signaling pathway has been determined to be one of the major players in EMT and CSCs. Therefore, we analyzed patient survival data to determine a correlation between the expression of Wnt components and overall survival. Of the several possible players, higher expression of GSK3β correlated with poorer overall patient survival. In support of this observation, we identified a GSK3β inhibitor, BIO, in a drug screen as one of the most potent inhibitors of EMT. Since TNBCs are enriched with mesenchymal-like cells, we treated mesenchymal cell lines with the GSK3β inhibitors and found that GSK3β inhibitors were among the few drugs that could selectively kill mesenchymal-like TNBC cells compared to epithelial-like breast cancer cells. To determine if GSK3β inhibitors specifically target mesenchymal-like cells by affecting the CSC population, we employed the mammosphere assay and analyzed the CD44hi/24lo population of vi these cell lines. We found that GSK3β inhibitors indeed decreased the CSC properties of the mesenchymal-like cell lines, and also decreased the expression of mesenchymal markers. Inhibition of GSK3β decreased the migratory properties suggesting that the inhibition of EMT by GSK3β inhibitor could contribute to the inhibitory effect of GSK3β on the migratory potential of the mesenchymal-like cells. Taken together, our studies demonstrate that GSK3β is a novel target for TNBCs and suggest that the GSK3β inhibitors could serve as selective inhibitors of EMT and CSC properties of the aggressive TNBCs, and may hence be ideal for combination treatment with standard-of-care drugs for women with this deadly disease. vii GSK3β REGULATES EPITHELIAL-MESENCHYMAL TRANSITION AND CANCER STEM CELL PROPERTIES AND IS A NOVEL DRUG TARGET FOR TRIPLE-NEGATIVE BREAST CANCER. Contents Acknowledgement ................................................................................................................... iv Abstract .................................................................................................................................... vi List of tables ............................................................................................................................. xi List of figures .......................................................................................................................... xii Chapter 1 – TNBC and the potential role of EMT, CSCs and GSK3β. ................................... 1 1A. Introduction to Triple-Negative Breast Cancer (TNBC). ...............................................