Exploring Epigenetic Dynamics Unveils a Super-Enhancer-Mediated NDRG1-β-Catenin Axis in Modulating Gemcitabine Resistance in Pancreatic Cancer

Chemoresistance remains a formidable challenge in pancreatic ductal adenocarcinoma (PDAC) treatment, necessitating a comprehensive exploration of underlying molecular mechanisms. This work aims to investigate the dynamic epigenetic landscape during the development of gemcitabine resistance in PDAC, with a specific focus on super-enhancers and their regulatory effects. We employed well-established gemcitabine-resistant (Gem-R) PDAC cell lines to perform high-throughput analyses of the epigenome, enhancer connectome, and transcriptome. Our findings revealed notable alterations in the epigenetic landscape and genome architecture during the transition from gemcitabine-sensitive to -resistant PDAC cells. Remarkably, we observed substantial plasticity in the activation status of super-enhancers, with a considerable proportion of these cis-elements becoming deactivated in chemo-resistant cells. Furthermore, we pinpointed the NDRG1 super-enhancer (NDRG1-SE) as a crucial regulator in gemcitabine resistance among the loss-of-function super-enhancers. NDRG1-SE deactivation induced activation of WNT/β-catenin signaling, thereby conferring gemcitabine resistance. This work underscores a NDRG1 super-enhancer deactivation-driven β-catenin pathway activation as a crucial regulator in the acquisition of gemcitabine-resistance. These findings advance our understanding of PDAC biology and provide valuable insights for the development of effective therapeutic approaches against chemoresistance in this malignant disease.