title: Identification and characterization of a novel small-molecule inhibitor of β-catenin signaling.
abstract: Hepatocellular carcinoma (HCC), the third most common cause of cancer-related deaths worldwide, lacks effective medical therapy. Large subsets of HCC demonstrate Wnt/β-catenin activation, making this an attractive therapeutic target. We report strategy and characterization of a novel small-molecule inhibitor, ICG-001, known to affect Wnt signaling by disrupting β-catenin-CREB binding protein interactions. We queried the ZINC online database for structural similarity to ICG-001 and identified PMED-1 as the lead compound, with ≥70% similarity to ICG-001. PMED-1 significantly reduced β-catenin activity in hepatoblastoma and several HCC cells, as determined by TOPflash reporter assay, with an IC50 ranging from 4.87 to 32 μmol/L. Although no toxicity was observed in primary human hepatocytes, PMED-1 inhibited Wnt target expression in HCC cells, including those with CTNNB1 mutations, and impaired cell proliferation and viability. PMED-1 treatment decreased β-catenin-CREB binding protein interactions without affecting total β-catenin levels or activity of other common kinases. PMED-1 treatment of Tg(OTM:d2EGFP) zebrafish expressing GFP under the β-catenin/Tcf reporter led to a notable decrease in β-catenin activity. The PMED effect on β-catenin signaling lasted from 12 to 24 hours in vitro and 6 to 15 hours in vivo. Thus, using a rapid and cost-effective computational methodology, we have identified a novel and specific small-molecule inhibitor of Wnt signaling that may have implications for HCC treatment.
authors.affiliation: Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
authors.forename: Evan R
authors.initials: ER
authors.lastname: Delgado
authors.affiliation: Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
authors.forename: Juhoon
authors.initials: J
authors.lastname: So
authors.affiliation: Department of Pharmacology, University of Virginia, Charlottesville, Virginia, Los Angeles, California.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Leimgruber
authors.affiliation: Department of Molecular Pharmacology and Toxicology, School of Pharmacy, Keck School of Medicine, University of Southern California, Los Angeles, California.
authors.forename: Michael
authors.initials: M
authors.lastname: Kahn
authors.affiliation: Division of Cell Regulation Systems, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.
authors.forename: Tohru
authors.initials: T
authors.lastname: Ishitani
authors.affiliation: Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
authors.forename: Donghun
authors.initials: D
authors.lastname: Shin
authors.affiliation: Department of Health Services and Health Administration, University of Southern Indiana, Evansville, Indiana. Electronic address: gmwilson@usi.edu.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Mustata Wilson
authors.affiliation: Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania. Electronic address: smonga@pitt.edu.
authors.forename: Satdarshan P
authors.initials: SP
authors.lastname: Monga
mesh_terms: D000818:Animals; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D050882:CREB-Binding Protein / Q000378:metabolism; D006528:Carcinoma, Hepatocellular / Q000378:metabolism; D045744:Cell Line, Tumor; D055808:Drug Discovery; D006801:Humans; D020128:Inhibitory Concentration 50; D008113:Liver Neoplasms / Q000378:metabolism; D011744:Pyrimidinones / Q000494:pharmacology; D013329:Structure-Activity Relationship; D060449:Wnt Signaling Pathway / Q000187:drug effects*; D015027:Zebrafish; D051176:beta Catenin / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; C495270:CTNNB1 protein, human; C492448:ICG 001; D011744:Pyrimidinones; D051176:beta Catenin; D050882:CREB-Binding Protein