Despite being the leading cause of cancer death, targeted therapy for gastric cancer is yet to be established. Wnt/β-catenin signaling is highly deregulated in cancers of gastrointestinal origin including gastric cancers. Stabilization and deregulation of β-catenin occurs at multiple levels and so is being needed to identify a spectrum of Wnt inhibitors to combat deregulated Wnt signaling at the level of various targets and also in different combinations. We developed a luciferase reporter based gastric cancer cellular assay system for Wnt pathway modulator screening and identified nimesulide, a known COX-2 inhibitor as an inhibitor of Wnt/β catenin signaling pathway. Comprehensive signaling pathway profiling revealed that nimesulide could inhibit STAT3, IRF1 and RXR signaling apart from inhibiting Wnt/β-catenin-Myc-E2F signaling cascade. Nimesulide elicits a strong anti-proliferative effect by promoting cell cycle arrest in multiple gastric cancer cell lines. Inhibition of Wnt and STAT3 signaling are found to be COX-2 independent, while the inhibition of RXR and IRF1 pathways are due to the COX-2 inhibiting feature of nimesulide. While nimesulide is capable of activating Notch signaling in gastric cancer cells, celecoxib inhibits Wnt, Myc, E2F, RXR, STAT3, MAPK and Notch signaling pathways in gastric cancer cells. Signaling pathway focused analysis of gastric cancer transcriptome revealed that Wnt, STAT3, IRF1 and RXR signaling pathways are highly deregulated in majority of gastric tumors and indicates the potential of nimesulide and celecoxib class of drugs for targeted gastric cancer therapeutics. The differential inhibition of multiple signaling by nimesulide and celecoxib deserve further investigation.
All Science Journal Classification (ASJC) codes
- Cancer Research