Abstract C041: Emerging role of P2X receptors as Golgi pH regulators in pancreatic cancer

Abstract Cancer cells reprogram their metabolism to meet their elevated energy demands, favoring energy production via glycolysis even with functional mitochondria. Upregulated glycolysis results in rapid production of lactate and protons in the cytoplasm. This would normally reduce the intracellular pH (pHi); however, cancer cells employ mechanisms such as ion transporters that remove excess protons from the cytoplasm to maintain an alkaline pHi, allowing for cell growth, evasion of cell death and cell proliferation. Our previous studies have shown that in pancreatic ductal adenocarcinoma (PDAC), the Golgi apparatus is among the intracellular compartments that can uptake excess protons, giving PDAC cells a cell fitness advantage. The underlying mechanisms that drive Golgi acidification in PDAC are incompletely understood. Here, we set out to comprehensively identify novel modulators that can affect this process. By using a fluorescent-protein-based ratiometric pH biosensor targeted to the Golgi membrane, we screened thousands of chemical compounds for an impairment in Golgi acidification, which would lead to pHi dysregulation and cell death. One of our hits from the screen was an inhibitor of the P2X family of receptors (P2XRs). P2XRs consist of seven subtypes (P2X1-7) and are ATP-gated ion channels that mediate the passage of non-selective cations through the plasma membrane and intracellular compartments. P2XRs have also been shown to regulate the pHi. We are elucidating the mechanism by which P2XRs may regulate pHi via the Golgi in PDAC. Our preliminary results show that concomitant with the alkalinization of the Golgi, P2XR inhibition leads to a pronounced decrease of pHi and results in cell death in PDAC while normal untransformed pancreas cells are unaffected. These data suggest that P2XRs play a role in pHi regulation and cell fitness maintenance through a function in the Golgi. Targeting this metabolic reprograming dependency may serve as a novel therapeutic tool for PDAC. Citation Format: Cheska Marie Galapate, Koen Galenkamp, Charles Fisher, Susanne Heynen-Genel, Cosimo Commisso. Emerging role of P2X receptors as Golgi pH regulators in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr C041.