Abstract B040: WNK kinases in pancreatic cancer: Novel regulators of macropinocytosis and potentiators of glutamine-targeted therapy

Abstract Pancreatic ductal adenocarcinoma (PDAC) remains a highly treatment-resistant cancer, in part due to metabolic adaptations that sustain tumor growth in the nutrient-poor microenvironment. To survive such conditions, PDAC cells utilize glutamine to fuel many metabolic processes, making it a promising therapeutic vulnerability. PDAC cells meet their glutamine demand by stimulating macropinocytosis, an endocytic pathway that imports extracellular proteins and targets them for lysosome-dependent degradation, thus serving as an amino acid supply route. Here, we identify the With No Lysine Kinase (WNK) family of kinases as novel, targetable regulators of macropinocytosis. We demonstrate that loss of WNK activity by genetic depletion or pharmacological inhibition reduces macropinocytosis across human, murine, and primary cell models. Characterization of WNK isoform expression in both 2D and 3D patient-derived organoid models revealed several WNKs upregulated in PDAC relative to normal tissue. Mechanistically, we found that targeting the predominant WNK isoform in PDAC is sufficient to reduce macropinocytosis. To target glutamine pathways, we utilized the glutamine antagonist 6-diazo-5-oxo-L-norleucine (DON). We previously demonstrated that DON treatment suppresses tumor growth and leads to an increase in macropinocytosis as a metabolic adaptation, and we surmised that this macropinocytic induction could be dampening its effectiveness as a single agent. Notably, we identified a synergistic relationship between a WNK inhibitor and DON, suggesting that WNK inhibitors might represent a promising approach for combination therapies with DON. Altogether, these findings establish WNKs as key regulators of macropinocytosis, highlighting their potential as therapeutic targets in PDAC. Citation Format: Aaliyah N. Balagtas, Guillem Lambies, Isabella Ng, Hervé Tiriac, Andrew M. Lowy, Cosimo Commisso. WNK kinases in pancreatic cancer: Novel regulators of macropinocytosis and potentiators of glutamine-targeted therapy [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(18_Suppl_3):Abstract nr B040.