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

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 PDAC, with a focus on identifying potential therapeutic targets within the nicotinate and nicotinamide metabolic pathways.

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. In addition, 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.

Compared with 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 was 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.

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.