title: Identification of Polo-like kinase 1 interaction inhibitors using a novel cell-based assay.
abstract: Polo-like kinase 1 (Plk1) plays several roles in cell division and it is a recognized cancer drug target. Plk1 levels are elevated in cancer and several types of cancer cells are hypersensitive to Plk1 inhibition. Small molecule inhibitors of the kinase domain (KD) of Plk1 have been developed. Their selectivity is limited, which likely contributes to their toxicity. Polo-like kinases are characterized by a Polo-Box Domain (PBD), which mediates interactions with phosphorylation substrates or regulators. Inhibition of the PBD could allow better selectivity or result in different effects than inhibition of the KD. In vitro screens have been used to identify PBD inhibitors with mixed results. We developed the first cell-based assay to screen for PBD inhibitors, using Bioluminescence Resonance Energy Transfer (BRET). We screened through 112 983 compounds and characterized hits in secondary biochemical and biological assays. Subsequent Structure-Activity Relationship (SAR) analysis on our most promising hit revealed that it requires an alkylating function for its activity. In addition, we show that the previously reported PBD inhibitors thymoquinone and Poloxin are also alkylating agents. Our cell-based assay is a promising tool for the identification of new PBD inhibitors with more drug-like profiles using larger and more diverse chemical libraries.
authors.affiliation: Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada.
authors.forename: Karine
authors.initials: K
authors.lastname: Normandin
authors.affiliation: Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Lavallée
authors.affiliation: Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada.
authors.forename: Marie
authors.initials: M
authors.lastname: Futter
authors.affiliation: Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Beautrait
authors.affiliation: Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada.
authors.forename: Jean
authors.initials: J
authors.lastname: Duchaine
authors.affiliation: Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Guiral
authors.affiliation: Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada.|Département de chimie, Université de Montréal, Montréal, Canada.
authors.forename: Anne
authors.initials: A
authors.lastname: Marinier
authors.affiliation: Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada.|Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, Canada.
authors.forename: Vincent
authors.initials: V
authors.lastname: Archambault
mesh_terms: D000477:Alkylating Agents / Q000737:chemistry / Q000494:pharmacology; D001565:Benzoates / Q000737:chemistry / Q000494:pharmacology; D016227:Benzoquinones / Q000737:chemistry / Q000494:pharmacology; D060807:Bioluminescence Resonance Energy Transfer Techniques; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors*; D057809:HEK293 Cells; D057166:High-Throughput Screening Assays; D006801:Humans; D054730:Protein Interaction Domains and Motifs; D047428:Protein Kinase Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors*; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors*; D011809:Quinones / Q000737:chemistry / Q000494:pharmacology; D054852:Small Molecule Libraries / Q000737:chemistry / Q000494:pharmacology; D013329:Structure-Activity Relationship; D000097869:Polo-Like Kinase 1
chemical_list: D000477:Alkylating Agents; D001565:Benzoates; D016227:Benzoquinones; D018797:Cell Cycle Proteins; D047428:Protein Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D011809:Quinones; D054852:Small Molecule Libraries; D000097869:Polo-Like Kinase 1; C569433:poloxin; C003466:thymoquinone