Abstract 5972: Therapeutic modulation of rock overcomes metabolic adaption to oxphos inhibition and suppresses tumor growth
Authors: Blazanin Nicholas , Liang Xiaobing , Mahmud Iqbal , Kim Eiru , Tan Lin , Anvar Nazanin Esmaeili , Chan Waikin , Ha Min Jin , Minelli Rosalba , Peoples Michael , Lorenzi Philip , Hart Travar , Lissanu Yonathan , Blazanin Nicholas 
Published: March 2024

Abstract
Lung cancer is the top cause of cancer mortality. Despite recent advances, the majority of patients with lung cancer still lack effective therapeutic options, underscoring the dire need for additional treatment approaches. Genomic studies have identified frequent mutations in subunits of the SWI/SNF chromatin remodeling complex including SMARCA4 and ARID1A in non-small cell lung cancer with a frequency of up to 33% in advanced stage disease, making it the most frequently mutated complex in lung cancer. Previous work in our lab, as well as others, have identified a metabolic vulnerability in targeting oxidative phosphorylation (OXPHOS) in SMARCA4-mutant lung cancer. However, OXPHOS inhibitors are still not approved to treat cancer due to modest efficacy and adverse effects. This strongly suggests that novel, efficacious and tolerated agents that synergize with OXPHOS inhibition are urgently needed. To this end, we undertook a functional genomics screen by utilizing a focused CRISPR-Cas9 library targeting genes with available FDA approved therapeutics in genetically defined lung cancer cell lines. Importantly, we utilized low doses of the OXPHOS inhibitor IACS-10759 that are known to be well tolerated in patients. Among our top validated hits was ROCK1/2 kinases and we demonstrate that Belumasudil, a clinically approved ROCK inhibitor with a robust safety and tolerability profile, displays a synergistic combination with IACS-10759. Furthermore, low doses of IACS-10759 synergized with ROCK inhibition in vivo eliciting marked tumor growth inhibition. Mechanistically, we showed that the combination of Belumasudil and IACS-10759 induced a profound energetic stress. This was primarily due to ROCK inhibition-mediated suppression of the normally observed adaptive increase in glycolysis upon OXPHOS inhibition. Steady-state metabolomics and C13-glucose isotope tracing confirmed downregulation of multiple glycolytic metabolites and reduced glycolytic flux by the combination of ROCK inhibition and IACS-10759 and was associated with severe reduction in glucose uptake. In summary, our study identified a key role of ROCK kinases in metabolic adaptation of cancer cells and provides a strong rationale for pursuing ROCK inhibitors as novel combination agents with OXPHOS inhibition and lay the foundation for future clinical investigation in genetically defined subtypes of lung cancer.
Citation Format: Nicholas Blazanin, Xiaobing Liang, Iqbal Mahmud, Eiru Kim, Lin Tan, Nazanin Esmaeili Anvar, Waikin Chan, Min Jin Ha, Rosalba Minelli, Michael Peoples, Philip Lorenzi, Travar Hart, Yonathan Lissanu, Nicholas Blazanin. Therapeutic modulation of rock overcomes metabolic adaption to oxphos inhibition and suppresses tumor growth [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5972.