# Elucidating how a USP9X-COP1 axis regulates RIT1 protein abundance and reveals druggable targets in lung adenocarcinoma > **NIH NIH F31** · FRED HUTCHINSON CANCER CENTER · 2022 · $41,619 ## Abstract PROJECT SUMMARY Targeted therapies have revolutionized cancer treatment and are becoming standard of care over cytotoxic chemotherapy. In lung cancer, where approximately 50% of tumors harbor druggable mutations in genes such as EGFR and ALK, targeted therapies are highly effective at reducing tumor burden; however, many mutations are not clinically actionable. Up to 13% of lung adenocarcinoma tumors are driven by mutation or amplification of the RAS-family protein RIT1, and RIT1 mutations do not co-occur with other canonical driver mutations. Because of this, there is a major unmet clinical need to identify effective targeted therapies for patients with RIT1-driven diseases. My career goal is to become a translational research scientist focused on identifying novel therapeutic options for cancer patients. The lack of therapeutic strategies for the treatment of RIT1-mutant lung cancer offers opportunities for me to build the skills, techniques, and expertise to address this problem and move towards my career objectives. This motivation led me to my thesis lab, where Dr. Berger developed a genome-wide CRISPR screening assay in human RIT1-mutant lung cancer cells. I helped analyze the CRISPR screen data and identified the deubiquitinase (DUB) USP9X and the E3 ligase COP1 as key regulators of RIT1 function. Validation experiments confirmed that individual loss of USP9X reverses RIT1-induced cell survival in lung cancer while loss of COP1 maintains RIT1-driven drug resistance. The results of the CRISPR screen provide rigorous, key support for this proposed project. Recent work suggests that the protein abundance of RIT1 is important for its oncogenic function; however, the exact DUBs and E3 ligases involved in regulating mutant RIT1 protein abundance have yet to be fully elucidated. Driven by this question, I initiated experiments to confirm that genetic knockout of USP9X decreases the abundance and stability of RIT1. I have also found that pharmacological inhibition of USP9X in vitro reduces RIT1 protein abundance, and preliminary in vivo experiments revealed that USP9X loss abrogates RIT1-driven xenograft tumor formation. Additionally, work from our collaborators demonstrates that RIT1 physically interacts with USP9X and COP1. Together, these data propose a regulatory axis of RIT1 protein abundance mediated by USP9X and COP1. I hypothesize that USP9X de-ubiquitinates and stabilizes RIT1 and that COP1 counteracts this regulation. Pharmacological inhibition of USP9X could therefore specifically target oncogenic RIT1. Ultimately, this work will reveal a novel mechanism of RIT1 protein regulation and could uncover the utility of USP9X inhibitors to address a major unmet clinical need for patients with RIT1-mutant or -amplified diseases. This project will build upon my skills in genomics and biochemistry while providing necessary training with in vivo murine systems. I will be able to translate my findings at the bench to mouse models, thereby expandi... ## Key facts - **NIH application ID:** 10536485 - **Project number:** 1F31CA271637-01A1 - **Recipient organization:** FRED HUTCHINSON CANCER CENTER - **Principal Investigator:** Amanda Riley - **Activity code:** F31 (R01, R21, SBIR, etc.) - **Funding institute:** NIH - **Fiscal year:** 2022 - **Award amount:** $41,619 - **Award type:** 1 - **Project period:** 2022-08-01 → 2024-07-31 ## Primary source NIH RePORTER: https://reporter.nih.gov/project-details/10536485 ## Citation > US National Institutes of Health, RePORTER application 10536485, Elucidating how a USP9X-COP1 axis regulates RIT1 protein abundance and reveals druggable targets in lung adenocarcinoma (1F31CA271637-01A1). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10536485. Licensed CC0. --- *[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*