The Wnt signaling pathway is required during embryonic development and for the maintenance of homeostasis in adult tissues. However, aberrant activation of the pathway is implicated in a number of human disorders, including cancer of the gastrointestinal tract, breast, liver, melanoma, and hematologic malignancies. In this study, we identified monensin, a polyether ionophore antibiotic, as a potent inhibitor of Wnt signaling. The inhibitory effect of monensin on the Wnt/β-catenin signaling cascade was observed in mammalian cells stimulated with Wnt ligands, glycogen synthase kinase-3 inhibitors, and in cells transfected with β-catenin expression constructs. Furthermore, monensin suppressed the Wnt-dependent tail fin regeneration in zebrafish and Wnt- or β-catenin-induced formation of secondary body axis in Xenopus embryos. In Wnt3a-activated HEK293 cells, monensin blocked the phoshorylation of Wnt coreceptor low-density lipoprotein receptor related protein 6 and promoted its degradation. In human colorectal carcinoma cells displaying deregulated Wnt signaling, monensin reduced the intracellular levels of β-catenin. The reduction attenuated the expression of Wnt signaling target genes such as cyclin D1 and SP5 and decreased the cell proliferation rate. In multiple intestinal neoplasia (Min) mice, daily administration of monensin suppressed progression of the intestinal tumors without any sign of toxicity on normal mucosa. Our data suggest monensin as a prospective anticancer drug for therapy of neoplasia with deregulated Wnt signaling.

Authors' Affiliations Department of Cell and Developmental Biology CZ OPENSCREEN Institute of Molecular Genetics AS CR; Department of Organic Chemistry Faculty of Science Charles University Prague Prague; and Central European Institute of Technology Masaryk University Brno Czech Republic; and Zoologisches Institut 2 Universität Karlsruhe Karlsruhe Germany

References provided by Crossref.org

TROP2 Represents a Negative Prognostic Factor in Colorectal Adenocarcinoma and Its Expression Is Associated with Features of Epithelial-Mesenchymal Transition and Invasiveness

Msx1 loss suppresses formation of the ectopic crypts developed in the Apc-deficient small intestinal epithelium

Wnt Effector TCF4 Is Dispensable for Wnt Signaling in Human Cancer Cells

Wnt Signaling Inhibition Deprives Small Intestinal Stem Cells of Clonogenic Capacity