Abstract 1833: Polyisoprenylated cysteinyl amide inhibitors suppress growth, induce cytoskeletal and transcriptomic remodeling in multiple <i>KRAS</i> -mutated lung cancer cells.

Abstract Lung cancer remains the leading cause of cancer-related deaths globally, with KRAS mutations driving approximately 30% of cases. Although KRASG12C protein inhibitors such as Sotorasib and Adagrasib have improved therapeutic outcomes, intrinsic resistance and mutation heterogeneity such as KRASG12A limit their long-term efficacy. Therefore, novel agents capable of targeting multiple mutant KRAS variants are urgently needed. Polyisoprenylated cysteinyl amide inhibitors (PCAIs) are molecular mimics of the essential post-translational modifications of G-proteins such as KRAS, RHOA, CDC42, and RAC1 that are important for their interactions as part of functional protein complexes. PCAIs were designed to interfere with and disrupt the polyisoprenylation-dependent protein-protein interactions required for KRAS signaling. Here we evaluated the long-term effects of PCAIs (NSL-YHJ-2-27), versus Adagrasib and Sotorasib on NCI-H23, which normally carries mutant KRASG12C, and a derivative in which KRASG12C was replaced by KRASG12A. Treatment of NCI-H23 carrying KRASG12C with 3 µM Adagrasib or NSL-YHJ-2-27 showed consistent inhibition of cell proliferation, down by 82 and 87% respectively. However, Adagrasib at 3 µM inhibited proliferation of NCI-H23 carrying KRASG12A by just 19%, while Sotorasib had little to no effect. At the same time NSL-YHJ-2-27 inhibited NCI-H23 carrying KRASG12A by 88%. Proliferation of Sotorasib-treated mutant KRASG12C NCI-H23 rebounded to 54% by day 18 of continuous treatment, showing KRASG12C mutants can quickly adapt to resist Sotorasib. NSL-YHJ-2-27 inhibited the viability of NCI-H23 carrying either KRASG12C or KRASG12A, with respective EC50 values of 2.0 and 2.5 µM. NSL-YHJ-2-27 and Adagrasib at 2 µM disrupted F-actin filaments, increased cell rounding, and reduced mean cell area by 89 and 92%, respectively. Sotorasib showed a slight decrease in mean cell area of 15%. Transcriptomic profiling of NSL-YHJ-2-27-treated NCI-H23 cells carrying KRASG12C revealed three genes that were significantly upregulated and two that were downregulated. Proapoptotic genes such as CXCL2, WNT9A, PTX3 were elevated by 9, 12 and 10-fold, whereas motility and angiogenesis-associated genes such as TMSB15A and POSTN were downregulated by30 and 9-fold, respectively. Pathway enrichment highlighted alterations in cytoskeletal organization, adhesion, and KRAS-associated signaling networks. These findings support PCAIs as promising pan-mutant-KRAS-targeting therapeutic candidates against lung cancer. Citation Format: Desmond Kwakye, Chase Lilly, Kweku Ofosu-Asante, Jahnissi Frimpomah Odoom, Joshua Kofi Ablordeppey, Bianca Dal Bó, KARLA GONZALEZ, Chunli Yan, Matthew A. Gladstone, Kyle R. Phillips, Benjamin J. Ryder, Yong Huang, Ite A. Offringa, Nazarius Lamango. Polyisoprenylated cysteinyl amide inhibitors suppress growth, induce cytoskeletal and transcriptomic remodeling in multiple KRAS-mutated lung cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 1833.