Abstract 1156: GUK1 is a novel metabolic liability in oncogene-driven lung cancer
Authors: Schneider Jaime Laurel , Kurmi Kiran , Dhiman Ishita , Colapietro Roberta , Joshi Shakchhi , Johnson Christian , Yoda Satoshi , Paulo Joao , Ruiz Daniela , Stopka Sylwia , Baquer Gerard , Lin Jessica , Haigis Kevin , Agar Nathalie , Gygi Steven , Hata Aaron , Haigis Marcia 
Published: April 2023

Abstract
There is a longstanding desire to take therapeutic advantage of dysregulated metabolic states in cancer. While it has been appreciated that lung tumors rewire their cellular metabolic networks to support unrestrained proliferation, metabolic vulnerabilities have largely not been explored in the context of specific onco-genotypes. This represents a major gap in our understanding of how different oncogenic drivers in non-small cell lung cancer (NSCLC) confer reliance on discrete metabolic networks to sustain tumor growth. The goals of this project are (1) to investigate metabolic dependencies in distinct molecular subtypes of lung cancer and (2) to elucidate how metabolic reprogramming drives resistance to targeted therapy. Using patient-derived cell culture models and tumor specimens collected from patients with ALK-positive (ALK+) NSCLC, we identified that lung tumors with ALK rearrangements harbor a unique metabolic signature marked by reliance on anabolic nucleotide pathways. A phosphoproteomic screen in ALK+ patient-derived cells identified a novel metabolic target of ALK signaling, GUK1, the only known enzyme responsible for GDP synthesis. We show that ALK binds to and phosphorylates GUK1 and that ALK-mediated GUK1 phosphorylation augments GDP/GTP nucleotide biosynthesis. Steady-state and tracing metabolomic studies demonstrate that ALK inhibition and GUK1 phosphomutant are epistatic in guanine nucleotide production. Molecular dynamic modeling suggests that phosphorylation of GUK1 alters the dynamics of active site closure to enhance substrate processivity and protects GUK1 from a non-catalytic confirmation. Introduction of phosphomutant GUK1 into ALK+ patient-derived cell lines results in decreased tumor proliferation in vitro and in vivo in xenograft models. Spatially resolved mass spectrometry imaging of tumor specimens from ALK+ patients demonstrates significant enrichment of guanine nucleotides in ALK+ and phospho-GUK1+ tumor cells. We identified that other oncogenic fusion proteins regulate GUK1 phosphorylation, highlighting the need to further characterize GUK1 as a metabolic liability in NSCLC. Furthermore, a subset of patient-derived cell lines with resistance to ALK tyrosine kinase inhibitors (TKIs) exhibits increased expression and phosphorylation of GUK1, indicating that regulation of this metabolic enzyme may play a role in mediating acquired resistance. We anticipate these studies will pave the way for the development of new therapeutic approaches by exploiting metabolic vulnerabilities in oncogene-driven lung cancers.
Citation Format: Jaime Laurel Schneider, Kiran Kurmi, Ishita Dhiman, Roberta Colapietro, Shakchhi Joshi, Christian Johnson, Satoshi Yoda, Joao Paulo, Daniela Ruiz, Sylwia Stopka, Gerard Baquer, Jessica Lin, Kevin Haigis, Nathalie Agar, Steven Gygi, Aaron Hata, Marcia Haigis. GUK1 is a novel metabolic liability in oncogene-driven lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1156.