title: Small Molecule, NSC95397, Inhibits the CtBP1-Protein Partner Interaction and CtBP1-Mediated Transcriptional Repression.
abstract: Carboxyl-terminal binding protein (CtBP) is a transcriptional corepressor that suppresses multiple proapoptotic and epithelial genes. CtBP is overexpressed in many human cancers, and its overexpression increases stem cell-like features, epithelial-mesenchymal transition, and cancer cell survival. Knockdown of CtBP also increases apoptosis independent of p53 in cell culture. Therefore, targeting CtBP with small molecules that disrupt its interaction with transcription factor partners may be an effective cancer therapy. To elicit its corepressing effect, CtBP binds to a conserved peptide motif in each transcription factor partner. We developed an AlphaScreen high-throughput screening assay to monitor the interaction between CtBP and E1A (which mimics the interaction between CtBP and its transcriptional partners). We screened the LOPAC library of 1280 bioactive compounds and identified NSC95397, which inhibits the CtBP-E1A interaction (IC50 = 2.9 µM). The inhibitory activity of NSC95397 was confirmed using two secondary assays and a counterscreen. NSC95397 also behaved as a weak substrate of CtBP dehydrogenase activity and did not inhibit another dehydrogenase, lactase dehydrogenase. Finally, NSC95397 was able to disrupt CtBP-mediated transcriptional repression of a target gene. These studies present a new possibility for the development of a therapeutic agent targeting tumors through disrupting the CtBP transcriptional complex.
authors.affiliation: Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, USA.
authors.forename: Melanie A
authors.initials: MA
authors.lastname: Blevins
authors.affiliation: Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, Rockville, MD, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Kouznetsova
authors.affiliation: Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, USA.
authors.forename: Aaron B
authors.initials: AB
authors.lastname: Krueger
authors.affiliation: Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, Rockville, MD, USA.
authors.forename: Rebecca
authors.initials: R
authors.lastname: King
authors.affiliation: Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, Rockville, MD, USA.
authors.forename: Lesley Mathews
authors.initials: LM
authors.lastname: Griner
authors.affiliation: Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, Rockville, MD, USA.
authors.forename: Xin
authors.initials: X
authors.lastname: Hu
authors.affiliation: Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, Rockville, MD, USA.
authors.forename: Noel
authors.initials: N
authors.lastname: Southall
authors.affiliation: Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, Rockville, MD, USA.
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Marugan
authors.affiliation: Department of Dermatology, University of Colorado School of Medicine, Aurora, CO, USA.
authors.forename: Qinghong
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, Rockville, MD, USA.
authors.forename: Marc
authors.initials: M
authors.lastname: Ferrer
authors.affiliation: Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, USA qinghong.zhang@ucdenver.edu marc.ferrer@nih.gov rui.zhao@ucdenver.edu.
authors.forename: Rui
authors.initials: R
authors.lastname: Zhao
mesh_terms: D000429:Alcohol Oxidoreductases / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D055808:Drug Discovery / Q000379:methods; D005786:Gene Expression Regulation / Q000187:drug effects*; D057166:High-Throughput Screening Assays / Q000379:methods; D006801:Humans; D009285:Naphthoquinones / Q000494:pharmacology*; D011485:Protein Binding / Q000187:drug effects; D015203:Reproducibility of Results; D054852:Small Molecule Libraries; D013379:Substrate Specificity; D014158:Transcription, Genetic / Q000187:drug effects*
chemical_list: C451261:2,3-bis(2-hydroxyethylsulfanyl)-(1,4)naphthoquinone; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D009285:Naphthoquinones; D054852:Small Molecule Libraries; D000429:Alcohol Oxidoreductases; C096794:C-terminal binding protein
keywords: AlphaScreen; CtBP1; E1A; NSC95397; protein-protein interaction