3-Bromo-Isoxazoline Derivatives Inhibit GAPDH Enzyme in PDAC Cells Triggering Autophagy and Apoptotic Cell Death

Simple Summary Cancer cells largely use glycolysis to obtain both chemical energy (ATP) and metabolic intermediates for anabolic reactions, and several studies proved that the blockage of the glycolytic pathway is an efficient anticancer strategy. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a key tetrameric glycolytic enzyme, has raised considerable attention in recent years as a potential drug target in pathological conditions in which glycolytic flux has a crucial role. In cancers, a recognized involvement of the Warburg effect, as a key mechanism for cancer-cell energetic metabolism, favouring tumour progression and invasion, has contributed to highlight human GAPDH (hGAPDH) as an effective drug target to specifically hit cancer cells exhibiting metabolic dependence on glycolysis, without significantly affecting normal cells. In this study, we tested the effects of 3-bromo-isoxazoline derivatives specifically designed to bind and inhibit GAPDH activity, in pancreatic ductal-adenocarcinoma cells. A growing interest in the study of aerobic glycolysis as a key pathway for cancer-cell energetic metabolism, favouring tumour progression and invasion, has led to consider GAPDH as an effective drug target to specifically hit cancer cells. In this study, we have investigated a panel of 3-bromo-isoxazoline derivatives based on previously identified inhibitors of Plasmodium falciparum GAPDH (PfGAPDH). The compounds are active, to a different extent, as inhibitors of human-recombinant GAPDH. They showed an antiproliferative effect on pancreatic ductal-adenocarcinoma cells (PDAC) and pancreatic-cancer stem cells (CSCs), and among them two promising compounds were selected to be tested in vivo. Interestingly, these compounds were not effective in fibroblasts. The AXP-3019 derivative was able to block PDAC-cell growth in mice xenograft without apparent toxicity. The overall results support the assumption that selective inhibition of the glycolytic pathway, by targeting GAPDH, is an effective therapy for pancreatic cancer and that 3-bromo-isoxazoline derivatives represent a new class of anti-cancer compounds targeting glycolysis.