WNT7A/β-catenin signaling induces FGF1 and influences sensitivity to niclosamide in ovarian cancer

We previously characterized the link between WNT7A and the progression of ovarian cancer. Other groups have identified FGF1 as a relevant risk factor in ovarian cancer. Here, we show a linkage between these two signaling pathways that may be exploited to improve treatment and prognosis of patients with ovarian cancer. High expression of WNT7A and FGF1 are correlated in ovarian carcinomas and poor overall patient survival. A chromatin immunoprecipitation assay demonstrated that WNT7A/β-catenin signaling directly regulates FGF1 expression via TCF binding elements in the FGF1-1C promoter locus. In vitro gene manipulation studies revealed that FGF1 is sufficient to drive the tumor promoting effects of WNT7A. In vivo xenograft studies confirmed that the stable overexpression of WNT7A or FGF1 induced a significant increase in tumor incidence, while FGF1 knockdown in WNT7A overexpressing cells caused a significant reduction in tumor size. Niclosamide most efficiently abrogated WNT7A/β-catenin signaling in our model, inhibited β-catenin transcriptional activity and cell viability, and increased cell death. Furthermore, niclosamide decreased cell migration following an increase in E-cadherin subsequent to decreased levels of SLUG. The effects of niclosamide on cell functions were more potent in WNT7A overexpressing cells. Oral niclosamide inhibited tumor growth and progression in an intraperitoneal xenograft mouse model representative of human ovarian cancer. Collectively, these results indicate that FGF1 is a direct downstream target of WNT7A/β-catenin signaling and this pathway has potential as a therapeutic target in ovarian cancer. Moreover, niclosamide is a promising inhibitor of this pathway and may have clinical relevance.

Adenine nucleotide metabolism during the aggregation of human platelets by bovine factor VIII

Human platelets, prelabelled with [3H]-adenine in vitro, were aggregated biphasically by bovine fibrinogen/factor VIII, and the amounts and specific radioactivity of ADP and ATP as well as the radioactivity of ATP, ADP, AMP, IMP and hypoxanthine + inosine were determined intracellularly and extracellularly. During the second phase of aggregation, ATP and ADP were released (50% of total) with a specific radioactivity 15-20 times lower than that of the ATP and ADP retained in the cells. The specific radioactivity of the ATP and ADP in the cells increased during release. Radioactive ATP was converted to radioactive hypoxanthine during release. These findings correlated well with those obtained with collagen, and indicate that bovine factor VIII induces the platelet release reaction whereby the storage (non-metabolic) pool of ATP and ADP is released while the metabolic pool is retained.