NAMPT Modulates Gemcitabine Resistance in Pancreatic Cancer via the p53 Signaling Pathway

Objective: Pancreatic ductal adenocarcinoma (PDAC) is often diagnosed at an advanced stage. Although gemcitabine (GEM) is commonly used as the first-line chemotherapy, many patients eventually develop resistance. This study aims to investigate the role of nicotinamide phosphoribosyltransferase (NAMPT) in mediating gemcitabine resistance in pancreatic ductal adenocarcinoma (PDAC), with a focus on identifying potential therapeutic targets within the nicotinate and nicotinamide metabolic pathways. Methods: We established the gemcitabine-resistant pancreatic cancer cell line BxPC-3-GR9 to simulate acquired resistance development. Subsequently, we conducted LC/MS metabolomics assays to identify altered metabolic pathways during gemcitabine resistance development. Additionally, molecular and functional experiments targeting key enzymes in KEGG-enriched metabolic pathways to identify genes exhibiting significant changes. Mechanistically, transcriptome sequencing and molecular assays were employed to elucidate the regulatory mechanisms governing these target genes. Results: Compared to parent BxPC-3 cell lines, significant alterations in the nicotinate and nicotinamide metabolic pathways were found in BxPC-3-GR9. Furthermore, nicotinamide was the only metabolite shared during the enrichment process; higher expression of NAMPT was also detected in gemcitabine-resistant cell lines. NAMPT knockdown increased gemcitabine sensitivity in gemcitabine-resistant cells, which validated in inherently resistant cell lines. Transcriptome analysis and molecular experiments demonstrated that NAMPT regulates the p53 signaling pathway via CCND1/2, contributing to gemcitabine resistance. Conclusion: These findings suggest that NAMPT could serve as a promising therapeutic target to overcome gemcitabine resistance in PDAC, laying the groundwork for future clinical investigations aimed at modulating nicotinate and nicotinamide metabolism to improve treatment outcomes.