Evaluation of ß-Catenin Inhibition of Axitinib and Nitazoxanide in Human Monocyte-Derived Dendritic Cells.

Modulation of ß-catenin signaling has attractive therapeutic potential in cancer immunotherapy. Several studies have found that ß-catenin can mediate immune evasion in cancer and promote anti-inflammatory features of antigen-presenting dendritic cells. Many small molecular compounds that inhibit Wnt/ß-catenin signaling are currently in clinical development, but none have entered routine clinical use. New inhibitors of ß-catenin signaling are consequently desirable. Here, we have tested, in monocyte-derived dendritic cells, the effects of two small molecular compounds, axitinib and nitazoxanide, that previously have been discovered to inhibit ß-catenin signaling in colon cancer cells. Immature and lipopolysaccharide-matured dendritic cells prepared from healthy blood donor buffy coats were stimulated with 6-bromoindirubin-3'-oxime (6-BIO) to boost basal ß-catenin activity, and the effects of axitinib and nitazoxanide were compared with the commercial ß-catenin inhibitor ICG-001. Assays, including genome-wide RNA-sequencing, indicated that neither axitinib nor nitazoxanide demonstrated considerable ß-catenin inhibition. Both compounds were found to be less toxic to monocyte-derived dendritic cells than either 6-BIO or ICG-001. Axitinib stimulated several aspects of dendritic cell function, such as IL12-p70 secretion, and counteracted IL-10 secretion, according to the present study. However, neither axitinib nor nitazoxanide were found to be efficient ß-catenin inhibitors in monocyte-derived dendritic cells.

Dual Pro- and Anti-Inflammatory Features of Monocyte-Derived Dendritic Cells.

The transcription factor ß-catenin is able to induce tolerogenic/anti-inflammatory features in different types of dendritic cells (DCs). Monocyte-derived dendritic cells (moDCs) have been widely used in dendritic cell-based cancer therapy, but so far with limited clinical efficacy. We wanted to investigate the hypothesis that aberrant differentiation or induction of dual pro- and anti-inflammatory features may be ß-catenin dependent in moDCs. ß-catenin was detectable in both immature and lipopolysaccharide (LPS)-stimulated DCs. The ß-catenin inhibitor ICG-001 dose-dependently increased the pro-inflammatory signature cytokine IL-12p70 and decreased the anti-inflammatory signature molecule IL-10. The ß-catenin activator 6-bromoindirubin-3'-oxime (6-BIO) dose-dependently increased total and nuclear ß-catenin, and this was associated with decreased IL-12p70, increased IL-10, and reduced surface expression of activation markers, such as CD80 and CD86, and increased expression of inhibitory markers, such as PD-L1. 6-BIO and ICG-001 competed dose-dependently regarding these features. Genome-wide mRNA expression analyses further underscored the dual development of pro- and anti-inflammatory features of LPS-matured moDCs and suggest a role for ß-catenin inhibition in production of more potent therapeutic moDCs.