Abstract 3395: Polyisoprenylated cysteinyl amide inhibitors: Effects on RAS signaling pathway intermediates and viability of mutant KRAS African American lung cancer cell line

Abstract Mutated KRAS is the most common cancer driver gene in lung adenocarcinomas in all racial and ethnic groups, including Blacks/African Americans (B/AAs). Drugs developed to combat KRAS-driven cancers become less effective due to intrinsic changes in the cells resulting in resistance and relapse. Due to the enormous challenges encountered in developing direct KRAS inhibitors, agents targeting alternative downstream RAS mediator kinase enzymes of the MAPK and PI3K/AKT signaling pathways have been developed. However, other avenues that directly target KRAS and similar cancer drivers must be explored to obtain alternative effective therapies. PCAIs constitute a group of potential anticancer agents that we developed to specifically disrupt and suppress signaling by hyperactive G-proteins such as mutated KRAS. In previous studies, PCAIs stimulated MEK1/2, ERK1/2, p90RSK and AKT phosphorylation resulting in cell death. The present study aims to determine whether specific inhibitors of the kinases can reverse PCAIs-stimulated phosphorylation and cell death. PCAIs were thus tested against the KRAS mutant NCI- cell line H23 (from a B/AA patient) and compared to KRASG12C inhibitor Sotorasib and other kinase inhibitors drugs. The EC50 values for the PCAIs NSL-YHJ-2-27 and NSL-AB-45 were 4. 1 ± 0. 3 and 5. 5 ± 0. 1 μM, respectively, compared to Gefitinib (EGFR), Sotorasib (KRASG12C), Dabrafenib (BRAF), Selumetinib (MEK1/2), Ulixertinib (ERK1/2) and Ipatasertib (AKT) whose EC50 values were 83 ± 12. 9 μM, 38 ± 5. 5 μM, 33 ± 1. 2 μM, 71 ± 5. 3 μM, 11 ± 0. 2 μM, 12 ± 1. 0 μM, respectively. The results indicate that the PCAIs are more effective against NCI-H23 than the other kinase inhibitor drugs. Future work will determine the effects of co-treating cells with the PCAIs and the respective kinase inhibitors on cell viability and PCAIs-induced phosphorylation of the kinases. Supported by grants U54CA233396, U54CA233444, and U54CA233465 from the National Institutes of Health (NIH) /National Cancer Institute (NCI) and the Norris Comprehensive Cancer Center core grant, award number P30CA014089 from the NIH/NCI Citation Format: Justin K. Mensah-Mamfo, Kweku Ofosu-Asante, Jassy Mary Lazarte, Amarender Goud Burra, Sofia A. Lugo, Yong Huang, Ite A. Offringa, Nazarius S. Lamango. Polyisoprenylated cysteinyl amide inhibitors: Effects on RAS signaling pathway intermediates and viability of mutant KRAS African American lung cancer cell line 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 (6Suppl): Abstract nr 3395.