Upregulated NOX1 expression in gallbladder cancer-associated fibroblasts predicts a poor prognosis

Gallbladder cancer (GBC) is a lethal aggressive malignant neoplasm of the biliary tract. Potential prognostic markers and therapeutic targets for this disease are urgently required. Cancer-associated fibroblasts (CAFs) play a key role in tumorigenesis and the development of cancer. Nicotinamide adenine dinucleotide phosphate oxidase 1 (NOX1) expression has been reported to be involved in tumorigenesis and useful for tumor prognosis. However, NOX1 expression in the stroma of GBCs, particularly gallbladder cancer-associated fibroblasts (GCAFs), and its prognostic significance in GBC patients remains unclear. In the present study, NOX1 expression in the stroma of human gallbladder lesions in vivo was investigated, as well as in GCAFs and co-cultures of GBC-SD+GCAFs in vitro, and their correlation with clinicopathological parameters and the prognosis of GBC patients were evaluated. The results revealed that NOX1 expression was significantly upregulated in the stroma of GBCs compared with precancerous and benign lesions of the gallbladder; NOX1 expression was localized to gallbladder stromal fibroblasts expressing alpha-smooth muscle actin and fibroblast secreted protein-1. Furthermore, these observations were confirmed by the fact that NOX1 expression was upregulated in GCAFs as determined by Affymetrix gene profile chip analysis and reverse transcription-quantitative PCR. In addition, overexpression was observed in formed spheroids of GBC-SD+GCAF co-cultures by immunohistochemistry and western blotting in vitro. Thus, it was verified that NOX1 expression was upregulated in GCAFs. Furthermore, upregulated stromal NOX1 expression was correlated with aggressive characteristics such as differentiation degree (P=0.042), venous invasion (P=0.041), resection methods (P=0.002), and a lower survival rate (P=0.025, log-rank test) of patients with GBC. Stromal NOX1 expression (P=0.047) was an independent prognostic factor for the overall survival rate of patients with GBC. GBC patients with upregulated NOX1 expression in GCAFs had a poorer prognosis. These results revealed that stromal NOX1 may be a novel biomarker and/or target, and may contribute to the discovery of new tumor markers and potential targeted therapeutics for human GBCs.