Glycyrrhetinic Acid and Autocrine Motility Factor Converge on G6PD Suppression, Oxidative Stress, and Drug Retention to Impair Pancreatic Ductal Adenocarcinoma Cell Growth

Abstract

Background/Aim: Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal malignancies, driven by chemoresistance and metabolic reprogramming centered on glucose-6-phosphate dehydrogenase (G6PD)-dependent pentose phosphate pathway activity. Exogenously administered autocrine motility factor (AMF) suppresses G6PD at transcriptional and protein levels, elevating intracellular reactive oxygen species (ROS) to cytostatic thresholds. Glycyrrhetinic acid (GA), a bioactive triterpenoid from licorice root, amplifies oxidative stress through mitochondrial membrane disruption, while concurrently downregulating multidrug resistance-associated ABC transporters. Materials and Methods: Three PDAC cell lines were treated with AMF variants and GA. Cell viability was assessed by MTT assay and clonogenic survival assays. Mechanistic endpoints included DCFDA fluorescence, Western blotting, RT-qPCR, and doxorubicin/Hoechst 33342 fluorescence for drug retention analysis. Results: Among eight distinct AMF variants, HG-AMF demonstrated the greatest cytotoxic potency both alone and in combination with GA. HG-AMF suppressed G6PD mRNA and protein expression, inducing sustained ROS accumulation confirmed by DCFDA fluorescence. Co-treatment with GA produced enhanced ROS generation, clonogenic suppression, decreased mitochondrial membrane potential, and impaired drug efflux. Conclusion: HG-AMF and GA converge on G6PD-dependent metabolism and chemoresistance pathways, providing a rational basis for their combined application in PDAC therapy.