Unveiling the 4-aminoquinoline derivatives as potent agents against pancreatic ductal adenocarcinoma (PDAC) cell lines.

Common antimalarials such as artemisinins, chloroquine and their derivatives also possess potent anti-inflamantory, antiviral and anticancer properties. In the search for new therapeutics to combat difficult-to-treat pancreatic carcinomas, we unveiled that 4-aminoquinoline derivatives, with significant antiplasmodial properties and a great safety profile in vivo, have remarkable anticancer activity against pancreatic ductal adenocarcinoma (PDAC) and considerable efficacy in the xenograft model in vivo. The aim of the present study was to further investigate anticancer properties of these compounds in a drug-repurposing manner. The compounds showed profound cytotoxic effects at nanomolar to low micromolar concentration in 2D cultured cells (in vitro) and in the zebrafish PDAC xenograft model (in vivo). A deeper insight into their mechanisms of cytotoxic action showed these compounds induce apoptosis while increasing reactive oxygen species levels along with autophagy inhibition. Additional investigation of the autophagy modulation proved that tested quinoline derivatives cause P62 and LC3-II accumulation in PDAC cells alongside lysosomal alkalinization. Further, in vivo toxicity studies in the zebrafish model showed low toxicity without developmental side effects of the investigated 4-aminoquinolines, while the applied compounds effectively inhibited tumor growth and prevented the metastasis of xenografted pancreatic cells. Taken together, these results highlight the 4-aminoquinolines as privileged structures that ought to be investigated further for potential application in pancreatic carcinoma treatment.