Disulfiram/Copper Complex Induces Cytotoxicity in Pancreatic Cancer Cells and 5-Fluorouracil-Resistant Cells through Nuclear Factor E2-Related Factor-2 Suppression and Reactive Oxygen Species Modulation

Abstract

Background/Aims: Pancreatic ductal adenocarcinoma (PDAC) is a challenging cancer to treat and has a poor prognosis and limited treatment options. In this study, the anticancer effects of disulfiram combined with copper (DSF/Cu) on PDAC cells, including those resistant to 5-fluoro-uracil, was assessed. Methods: Human pancreatic cancer cells (BxPC-3 and CFPAC-1) and their 5-fluorouracil-re-sistant (5FUR) counterparts were treated with DSF/Cu to assess cytotoxicity. Expression levels of nuclear factor E2-related factor-2 (NRF-2) and heme oxygenase-1 (HO-1) were analyzed by reverse transcription quantitative polymerase chain reaction and Western blotting, while intracellular reactive oxygen species (ROS) levels were evaluated using H2DCFDA staining and flow cytometry. The effects of DSF/Cu on protein kinase B (Akt) and mitogen-activated protein kinase (MAPK) signaling pathways were evaluated by Western blot analysis. In vivo efficacy was investigated using a xenograft mouse model, in which mice were orally administered DSF (75 mg/kg) and Cu (2 mg/kg) twice weekly for 5 weeks. Results: We demonstrated that DSF/Cu effectively induced cytotoxicity in both pancreatic cancer cells and their 5FUR counterparts by modulating ROS levels, NRF-2 levels, and associated survival pathways. DSF/Cu treatment significantly decreased NRF-2 expression and reduced ROS levels, specifically in 5FUR cells. DSF/Cu facilitated NRF-2-independent HO-1 expression and differentially modulated Akt and MAPK signaling pathways in pancreatic cancer cells and their 5FUR counterparts. In vivo studies using a xenograft mouse model confirmed the antitumor efficacy of DSF/Cu, as evidenced by reduced tumor volumes and NRF-2 expression. Conclusions: These findings highlight the potential of DSF/Cu as a novel and effective therapeutic strategy for PDAC, specifically for overcoming resistance to standard therapies. (Gut Liver, Published online July 25, 2025)