Neuropilin-1 is up-regulated by cancer-associated fibroblast-secreted IL-8 and associated with cell proliferation of gallbladder cancer

We previously demonstrated that cancer‐associated fibroblasts (CAFs) promoted the proliferation of gallbladder cancer (GBC) cells, but the mechanism is not clear. Neuropilin‐1 (NRP‐1) plays an important role in various malignancies as transmembrane glycoprotein. Our goal was to reveal the relationship between CAFs and NRP‐1 and their potential functions in GBC. In this study, we found NRP‐1 was overexpressed in GBC tissue, associated with poor survival and was up‐regulated by CAFs. The cytokine array cluster analysis revealed IL‐8 secreted by CAFs facilitated the up‐regulation of NRP‐1 in tumour cells. NRP‐1 knockdown suppressed tumour growth in vivo. Gene expression microarray analysis showed 581 differentially regulated genes under NRP‐1 knockdown conditions. Ingenuity pathway analysis demonstrated that NRP‐1 knockdown may inhibit tumour progression by affecting cell proliferation. We then confirmed that NRP‐1 knockdown in NOZ and GBC‐SD cells significantly inhibited cell proliferation. Additionally, the IL‐8 mediated MDM2 and CCNA2 expression were affected by NRP‐1 knockdown. Our findings suggested that NRP‐1 was up‐regulated by CAF‐secreted IL‐8, which subsequently promoted GBC cell proliferation, and these molecules may serve as useful prognostic biomarkers and therapeutic targets for GBC.