Abstract B083: Defining a molecular basis and therapeutic approach for KEAP1-NRF2 mediated resistance to KRAS inhibition in KRAS-mutant pancreatic ductal adenocarcinoma

Abstract Mutational activation of KRAS is critical for driving the tumorigenic growth of pancreatic ductal adenocarcinoma (PDAC). Recent clinical observations with the approved KRASG12C selective inhibitors sotorasib and adagrasib support the therapeutic value of targeting KRAS in PDAC. However, long-term efficacy is hindered by both primary and treatment-associated acquired resistance, and it is likely applicable to other types of KRAS inhibitors targeting different mutant alleles. To define the mechanisms behind resistance to KRAS inhibition, we performed a CRISPR loss-of-function screen to identify genes modulating the sensitivity of PDAC cells to KRAS inhibition. The screen identified loss of KEAP1 as a significant driver of resistance to inhibitors targeting KRAS. KEAP1 negatively regulates the transcription factor NRF2, which orchestrates transcription of genes that drive the anti-oxidative stress response and promote cell survival. We verified that knockout of KEAP1 drove NRF2-dependent resistance to KRAS inhibition. To elucidate the mechanism of KEAP1 loss-mediated resistance, RNA-sequencing analyses in KEAP1-depleted cancer cells revealed that KEAP1 loss protected cancer cells from oxidative stress and cell cycle arrest induced by KRAS inhibition. We then established a PDAC KEAP1-deficient (PKD) gene signature, which was found prevalent in patients and models insensitive to KRAS inhibitor treatment. This gene set was distinct from transcriptional changes associated with other transcriptional signatures driving resistance to KRAS inhibitors (ERK, MYC and YAP/TAZ-TEAD). Finally, analysis of KEAP1-loss associated genes also identified the activation of glutamine metabolism, and we found the combination treatment with the glutamine antagonist DRP-104 enhanced KRAS inhibitor-mediated growth suppression in PDAC patient-derived organoids. In summary, our studies have established the molecular mechanisms underlying KEAP1-NRF2 pathway-driven resistance to KRAS inhibition and validated a potential therapeutic strategy to overcome this resistance. Citation Format: Wen-Hsuan Chang, Addison G. Stamey, Runying Yang, Ryan Robb, Jeffery A. Klomp, Clint A. Stalnecker, Andrew M. Waters, Antje Schaefer, Kirsten L. Bryant, Adrienne D. Cox, Channing J. Der. Defining a molecular basis and therapeutic approach for KEAP1-NRF2 mediated resistance to KRAS inhibition in KRAS-mutant pancreatic ductal adenocarcinoma abstract. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research—Emerging Science Driving Transformative Solutions; Boston, MA; 2025 Sep 28-Oct 1; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2025;85 (18Suppl₃): Abstract nr B083.