Publication Date
2023
Document Type
Dissertation
Committee Members
Kwang-jin Cho, Ph.D. (Advisor); David R. Ladle, Ph.D. (Committee Member); Kuppuswamy Arumugam, Ph.D. (Committee Member); David Cool, Ph.D. (Committee Member); Michael Leffak, Ph.D. (Committee Member)
Degree Name
Doctor of Philosophy (PhD)
Abstract
Ras proteins are small GTPases that regulate cell proliferation, differentiation and survival at the plasma membrane (PM). There are three Ras isoforms ubiquitously expressed in mammalian cells: H-, N- and K-Ras. Constitutively active Ras mutations are found in ~19% of all human cancers, with ~75% of those being in K-Ras. There are K-Ras inhibitors in clinic but they only target the oncogenic K-RasG12C mutant, which only makes up a small sub-set of K-Ras-driven cancers. Thus, there still exists a need for a pan anti-K-Ras drug. Ferrocene derivatives are a class of compounds that have been shown to inhibit the growth of a lung cancer cell line harboring an oncogenic mutant K-Ras via their elevation of cellular reactive oxygen species (ROS). Given that lung cancer cells harboring an oncogenic mutant K-Ras require K-Ras signaling for their survival, the effect of a novel ferrocene derivative, C16H20FeClNO, on K-Ras signaling was tested. C16H20FeClNO was found to specifically disrupt the K-Ras/MAPK signaling pathway and inhibit the growth of K-Ras-dependent human pancreatic and lung cancer cell lines. Given that localization to the PM is essential for K-Ras signaling, the effect of C16H20FeClNO on K-Ras PM localization was tested. C16H20FeClNO was found to dissociate K-Ras, but not other Ras isoforms, from the PM. Furthermore, other ROS-elevating drugs had a similar effect on K-Ras PM localization and K-Ras signal output. C16H20FeClNO was shown to elevate cellular ROS levels and supplementation of N-acetylcysteine (NAC), a general antioxidant, reversed these effects, suggesting that C16H20FeClNO disrupts K-Ras PM localization and K-Ras signaling through an ROS-mediated mechanism. Lastly, K-Ras histidine 95 (His95) residue in the G-domain was identified as the oxidative residue involved in C16H20FeClNO-induced K-Ras dissociation from the PM. Overall, C16H20FeClNO disrupts K-Ras PM localization and signal output through oxidation of His95. Taken together, this dissertation identifies C16H20FeClNO as a novel K-Ras inhibitor and provides the groundwork for C16H20FeClNO to be developed into an anti-cancer drug.
Page Count
154
Department or Program
Biomedical Sciences
Year Degree Awarded
2023
Copyright
Copyright 2023, all rights reserved. My ETD will be available under the "Fair Use" terms of copyright law.
ORCID ID
0000-0003-0853-179x
