Macropinocytosis inhibits alkaliptosis in pancreatic cancer cells through fatty acid uptake.

Alkaliptosis, a form of regulated cell death, is characterized by lysosomal dysfunction and intracellular pH alkalinization. The pharmacological induction of alkaliptosis using the small molecule compound JTC801 has emerged as a promising anticancer strategy in various types of cancers, particularly pancreatic ductal adenocarcinoma (PDAC). In this study, we investigate a novel mechanism by which macropinocytosis, an endocytic process involving the uptake of extracellular material, promotes resistance to alkaliptosis in human PDAC cells. Through lipid metabolomics analysis and functional studies, we demonstrate that the inhibition of alkaliptosis by fatty acids, such as oleic acid, is not dependent on endogenous synthetic pathways but rather on exogenous uptake facilitated by macropinocytosis. Consequently, targeting macropinocytosis through pharmacological approaches (e.g. using EIPA or EHoP-016) or genetic interventions (e.g. RAC1 knockdown) effectively enhances JTC801-induced alkaliptosis in human PDAC cells. These findings provide compelling evidence that the modulation of macropinocytosis can increase the sensitivity of cancer cells to alkaliptosis inducers.