Norrin maintains malignancy of gastric cancer cells in part through activating AKT signaling.

Human tumorigenesis resembles embryogenesis by aberrant activation of several developmental pathways including Wnt/ß-catenin signaling. Norrin is an atypical ligand for Frizzled receptor that is preferentially expressed in the endothelium to promote retinal vascularization during development. However, its expression pattern and potential roles in human cancers remain unclear. Here we report that Norrin expression is elevated in the parenchymal cells, but not endothelial cells, in gastric cancer (GC). Moreover, Norrin is required for growth and invasion of GC cells and its expression status is associated with unfavorable outcomes. However, analysis of the TGCA database demonstrates that Norrin expression status is not correlated with key target genes of Wnt/ß-catenin signaling. Among several signaling pathways hyperactivated in cancer, Norrin-depleted GC cells also display down-regulated AKT signaling except the canonical Wnt/ß-catenin signaling. Consistently, small molecule-induced cytosolic activation of AKT partially rescues the proliferative and invasive capability of Norrin-depleted cells. Together, these findings suggest a novel role of Norrin in gastric tumorigenesis that could be exploited for adjuvant therapy against the deadly malignancy.

Optimized high-dose amoxicillin-proton-pump inhibitor dual therapies fail to achieve high cure rates in China.

Background\Aim: Quadruple daily administration of proton-pump inhibitor (PPI) therapy achieves potent acid inhibition, and combined with amoxicillin, with its pharmacodynamic and pharmacokinetic characteristics, may be efficient for Helicobacter pylori eradication. We compared the efficacy of two optimized high-dose dual therapies with a bismuth-containing quadruple regimen for treating H. pylori infection. Rabeprazole dosages for H. pylori eradication were also evaluated. PATIENTS AND METHODS: Treatment-naive and H. pylori-positive subjects were recruited and randomly apportioned to three treatment groups: Group A (n = 87), rabeprazole 10 mg plus amoxicillin 750 mg (4 times/day for 14 days); Group B (n = 87), rabeprazole 20 mg plus amoxicillin 750 mg (4 times/day for 14 days); and Group C (n = 89), bismuth-containing quadruple regimen consisting of rabeprazole 20 mg, bismuth 220 mg, amoxicillin 1000 mg, and clarithromycin 500 mg (2 times/day for 14 days). Four weeks after treatment discontinuation, patients were examined for H. pylori infection by 13C-urea breath test. The rates of adverse effects, compliance, and eradication were evaluated. RESULTS: Eradication rates in groups A, B, and C were 78.1, 81.6, and 84.3%, respectively, based on intention-to-treat analysis, or 79.1, 83.5, and 86.2%, according to per-protocol analysis. Rates of adverse events and compliance of the three groups were similar. CONCLUSION: For treating H. pylori infection, optimized high-dose amoxicillin-PPI dual therapies failed to achieve high cure rates in China and held no advantage over a bismuth-containing quadruple regimen.