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Investigating the Roles of P63 and P73 Isoforms to Therapeutically Treat P53-Altered Cancers

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Investigating the Roles of P63 and P73 Isoforms to Therapeutically Treat P53-Altered Cancers 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 5-2015 Investigating the roles of p63 and p73 isoforms to therapeutically treat p53-altered cancers Avinashnarayan Venkatanarayan Follow this and additional works at: https://digitalcommons.library.tmc.edu/utgsbs_dissertations Part of the Cancer Biology Commons, Molecular Biology Commons, Molecular Genetics Commons, and the Translational Medical Research Commons Recommended Citation Venkatanarayan, Avinashnarayan, "Investigating the roles of p63 and p73 isoforms to therapeutically treat p53-altered cancers" (2015). The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences Dissertations and Theses (Open Access). 576. https://digitalcommons.library.tmc.edu/utgsbs_dissertations/576 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]. INVESTIGATING THE ROLES OF P63 AND P73 ISOFORMS TO THERAPEUTICALLY TREAT P53-ALTERED CANCERS By Avinashnarayan Venkatanarayan, M.S. APPROVED: ______________________________ Elsa R. Flores, Ph.D. Advisory Professor ______________________________ Mong Hong Lee, Ph.D. ______________________________ Michael J. Galko, Ph.D. ______________________________ Kenneth Y. Tsai, M.D., Ph.D. ______________________________ Sendurai Mani, Ph.D. ______________________________ Preethi H. Gunaratne, Ph.D. APPROVED: ____________________________ Dean, The University of Texas Graduate School of Biomedical Sciences at Houston INVESTIGATING THE ROLES OF P63 AND P73 ISOFORMS TO THERAPEUTICALLY TREAT P53-ALTERED CANCERS A DISSERTATION Presented to the Faculty of The University of Texas Health Science Center at Houston and The University of Texas MD Anderson Cancer Center Graduate School of Biomedical Sciences in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY By Avinashnarayan Venkatanarayan, M.S. Houston, Texas May, 2015 Dedication To my grandmothers Janakavalli A & Shanthakumari P who have been a tremendous source of will power, dedication and humility iii Acknowledgements My training and success in the graduate school would have not been possible without the support, mentorship and blessings of many people. First and foremost, I would like to thank God, the Almighty for giving me the energy and health to complete this endeavor successfully. I would like to thank my mentor, Dr. Elsa Flores for accepting me as a graduate student in her laboratory; training me and importantly helping me achieve my goals. Dr. Flores has not only been a great mentor, but also a role model from whom I often draw inspiration, sometimes as my friend with whom I tend to chat and sometimes as my scientific mom for the care and affection she has provided me. I learnt to not only appreciate and perform science but more importantly the purpose we serve as scientists and the hope we give to the people by advancing cancer research. I am also fortunate to have the support and guidance of an excellent committee. Dr. Mong Hong Lee, Dr. Michael Galko, Dr. Sendurai Mani, Dr. Kenneth Tsai and Dr. Preethi Gunaratne have been excellent mentors and always provided me with constructive suggestions and helped me progress in my scientific career. I also wanted to to acknowledge three people, Dr. Elsa Flores, Dr. Michael Galko and Dr. Andreas Bergmann who offered me rotation positions in there labs and made my dream of pursuing a PhD program a reality. Also, I had the support and guidance of a small but highly talented group of people in the lab. I would like to thank all the present and former members of the Flores Lab. I would like to thank Dr. Min Soon Cho for helping me learn the basics iv when I was a rotation student. I had lot of help with the mouse work from Young Jin Gi, Lingzhi Liu and Payal Raulji. Dr. Xiaohua Su is an expert in our lab and she has always been my go to person. Dr. Marco Napoli has been a good friend and excellent person to bounce ideas from him. Marlese Pisegna has been our always- positive lab manager and my bench buddy. She has provided me with moral support and she was always there to share with me my failures and success. And finally, I would like to acknowledge my fellow graduate students Dr. Ramon Flores Gonzalez, Andrew Davis, Ngoc Bui and Sarah Wu. I think we started as lab mates and now we have become friends for life. Our repeated discussions on performing and improving experiments have made our lab a happening place. I would also like to thank and acknowledge the rotation and summer students who worked closely with me. Particularly, I would like to thank Pruthali Kulkarni and Eliot F. Sananikone for their motivation and enthusiasm while performing experiments in the lab. I would also like to thank my collaborators, Dr. William Norton (Veterinary Medicine) for his help with the mouse surgeries. Dr. James Bankson and members of the Small Animal Imaging Facility (SAIF) for their help with mouse imaging. Dr. Cristian Coarfa for his help with Bioinformatic analysis and Dr. Anil Sood, Dr. Mangala Selenere and Aguayo Cristian for their help with the liposomal siRNA particles. My success in graduate school is also greatly attributed to help and guidance from Dr. Abinav Jain and Dr. Srikanth Appikonda (Barton Lab), Dr. James Jackson and Dr. Vinod Pant (Lozano Lab) and Dr. Parameshwar Djardiane. We have become good friends over the last few years and I really cherish the time I spent with v all of them. I would also like to thank Elisabeth Lindheim, the Genes and Development program coordinator for her help and support for the last 6 years. Also, I would like to thank and acknowledge my family for their unconditional love and support during my training as a graduate student. My parents Mr. A. Venkatanarayan and Mrs. V. Ashalatha have always given me the freedom to pursue my interests and never doubted my actions. My brother Dr. Ajay Venkatanarayan, in many ways made sacrifices on my behalf so that I could complete my graduate school, by supporting my parents and being self-less. I also would like to thank my uncle Dr. A. Srinivasan who has always reminded me that hard work leads to success. Finally, I would like to thank my fiancée Ms. Amritha Sathish for her love, support and positive attitude. She has been highly understanding of my busy schedule and helped me stay focused. Finally, I would like to thank my friends who have been my pillars of strength throughout my graduate school. My friends have become like my family and I am excited to see what the future holds for each of us. I would like to thank Dr. Rajesha Rupaimoole my friend and roommate for the past 8 years. Rajesha and myself have a special understanding and we both have taken similar steps in our life at the same time. Also, I would like to thank Dr. Anantha and Anil Chukkapalli, Dr. Zeynep and Dr. Kadir Akdemir, Uphanya and Dr. Sridhar Eshwaran for their love, friendship and support. Also, a special thanks to Dr. Shankar Venugopalan and my buddies Bharat Chaganty and Dr. Kalyan Nallaparaju for always giving the best and positive advice. vi Investigating the roles of p63 & p73 isoforms to therapeutically treat p53-altered cancers Avinashnarayan Venkatanarayan, M.S. Supervisory Professor: Elsa R. Flores, Ph.D. The TP53 tumor suppressor is mutated in approximately 50% of human cancers rendering cancer therapies ineffective. p53 reactivation suppresses tumor formation in mice. However, this strategy has proven difficult to implement therapeutically. An alternate approach to overcome p53 loss is to manipulate the p53-family members, p63 and p73, which interact and share structural similarities to p53. p63 and p73, unlike p53 are less frequently mutated and have two major isoforms with distinct functions which makes them unique targets for therapeutic intervention. The full-length acidic transactivation (TA) isoforms of p63 and p73 function similar to p53. While the deltaN (ΔN) isoforms of p63 and p73, which lack the acidic transactivation domain, are overexpressed in cancers and function in a dominant negative manner against p53, TAp63 and TAp73. As result of the opposing isoform-specific function, the roles of p63 and p73 in tumorigenesis requires further characterization. In an attempt to identify novel therapeutic approaches to treat p53-altered cancers by utilizing the p53-family members, I aim to delineate the roles of ΔN isoforms of p63 and p73 in tumorigenesis. I have demonstrated that deletion of ΔNp63 or ΔNp73 in p53-deficient tumors mediates tumor regression through the upregulation of tumor suppressive isoforms, TAp63 and TAp73. Upon loss of ΔNp63 or ΔNp73, TAp63 and TAp73 activate IAPP vii a metabolic regulator, which induces metabolic reprogramming resulting in tumor regression in p53-deficient mice. I have shown that IAPP, which encodes amylin, a 37-amino acid peptide functions as a tumor suppressor in p53-deficient cancers. IAPP functions through the calcitonin and RAMP3 receptors to limit glucose uptake and reduce glycolysis in the cancer cells resulting in ROS accumulation and apoptosis. Additionally, I have also shown that use of Pramlintide, a synthetic analog of IAPP, mediates tumor regression in p53-deficient mice and apoptosis in multiple p53-mutant human cancer cell lines. Further, to therapeutically treat p53-deficient cancers in vivo, liposomal nanoparticle siRNA’s targeting ΔNp63 and ΔNp73 were administered into p53- deficient mouse thymic lymphomas, which resulted in tumor regression.
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