1
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Park JE, Lee H, Oliva P, Kirsch K, Kim B, Ahn JI, Alverez CN, Gaikwad S, Krausz KW, O’Connor R, Rai G, Simeonov A, Mock BA, Gonzalez FJ, Lee KS, Jacobson KA. Structural Optimization and Anticancer Activity of Polo-like Kinase 1 (Plk1) Polo-Box Domain (PBD) Inhibitors and Their Prodrugs. ACS Pharmacol Transl Sci 2023; 6:422-446. [PMID: 36926457 PMCID: PMC10012257 DOI: 10.1021/acsptsci.2c00250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Indexed: 02/22/2023]
Abstract
Polo-like kinase 1 (Plk1), a mitotic kinase whose activity is widely upregulated in various human cancers, is considered an attractive target for anticancer drug discovery. Aside from the kinase domain, the C-terminal noncatalytic polo-box domain (PBD), which mediates the interaction with the enzyme's binding targets or substrates, has emerged as an alternative target for developing a new class of inhibitors. Various reported small molecule PBD inhibitors exhibit poor cellular efficacy and/or selectivity. Here, we report structure-activity relationship (SAR) studies on triazoloquinazolinone-derived inhibitors, such as 43 (a 1-thioxo-2,4-dihydrothieno[2,3-e][1,2,4]triazolo[4,3-a]pyrimidin-5(1H)-one) that effectively block Plk1, but not Plk2 and Plk3 PBDs, with improved affinity and drug-like properties. The range of prodrug moieties needed for thiol group masking of the active drugs has been expanded to increase cell permeability and mechanism-based cancer cell (L363 and HeLa) death. For example, a 5-thio-1-methyl-4-nitroimidazolyl prodrug 80, derived from 43, showed an improved cellular potency (GI50 4.1 μM). As expected, 80 effectively blocked Plk1 from localizing to centrosomes and kinetochores and consequently induced potent mitotic block and apoptotic cell death. Another prodrug 78 containing 9-fluorophenyl in place of the thiophene-containing heterocycle in 80 also induced a comparable degree of anti-Plk1 PBD effect. However, orally administered 78 was rapidly converted in the bloodstream to parent drug 15, which was shown be relatively stable toward in vivo oxidation due to its 9-fluorophenyl group in comparison to unsubstituted phenyl. Further derivatization of these inhibitors, particularly to improve the systemic prodrug stability, could lead to a new class of therapeutics against Plk1-addicted cancers.
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Affiliation(s)
- Jung-Eun Park
- Cancer
Innovation Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Hobin Lee
- Cancer
Innovation Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
- Laboratory
of Bioorganic Chemistry, National Institute
of Diabetes and Digestive and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United States
| | - Paola Oliva
- Laboratory
of Bioorganic Chemistry, National Institute
of Diabetes and Digestive and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United States
| | - Klara Kirsch
- Cancer
Innovation Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Bora Kim
- Cancer
Innovation Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Jong Il Ahn
- Cancer
Innovation Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Celeste N. Alverez
- Cancer
Innovation Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
- Division
of Preclinical Innovation, National Center
for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850, United States
| | - Snehal Gaikwad
- Laboratory
of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of
Health, Bethesda, Maryland 20892, United States
| | - Kristopher W. Krausz
- Cancer
Innovation Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Robert O’Connor
- Laboratory
of Bioorganic Chemistry, National Institute
of Diabetes and Digestive and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United States
| | - Ganesha Rai
- Division
of Preclinical Innovation, National Center
for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850, United States
| | - Anton Simeonov
- Division
of Preclinical Innovation, National Center
for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850, United States
| | - Beverly A. Mock
- Laboratory
of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of
Health, Bethesda, Maryland 20892, United States
| | - Frank J. Gonzalez
- Cancer
Innovation Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Kyung S. Lee
- Cancer
Innovation Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Kenneth A. Jacobson
- Laboratory
of Bioorganic Chemistry, National Institute
of Diabetes and Digestive and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United States
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Stafford JM, Wyatt MD, McInnes C. Inhibitors of the PLK1 polo-box domain: drug design strategies and therapeutic opportunities in cancer. Expert Opin Drug Discov 2023; 18:65-81. [PMID: 36524399 DOI: 10.1080/17460441.2023.2159942] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
INTRODUCTION Polo Like Kinase 1 (PLK1) is a key regulator of mitosis and its overexpression is frequently observed in a wide variety of human cancers, while often being associated with poor survival rates. Therefore, it is considered a potential and attractive target for cancer therapeutic development. The Polo like kinase family is characterized by the presence of a unique C terminal polobox domain (PBD) involved in regulating kinase activity and subcellular localization. Among the two functionally essential, druggable sites with distinct properties that PLK1 offers, targeting the PBD presents an alternative approach for therapeutic development. AREAS COVERED Significant progress has been made in progressing from the peptidic PBD inhibitors first identified, to peptidomimetic and recently drug-like small molecules. In this review, the rationale for targeting the PBD over the ATP binding site is discussed, along with recent progress, challenges, and outlook. EXPERT OPINION The PBD has emerged as a viable alternative target for the inhibition of PLK1, and progress has been made in using compounds to elucidate mechanistic aspects of activity regulation and in determining roles of the PBD. Studies have resulted in proof of concept of in vivo efficacy suggesting promise for PBD binders in clinical development.
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Affiliation(s)
- Jessy M Stafford
- Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC, USA
| | - Michael D Wyatt
- Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC, USA
| | - Campbell McInnes
- Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC, USA
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3
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Zhang J, Zhang L, Wang J, Ouyang L, Wang Y. Polo-like Kinase 1 Inhibitors in Human Cancer Therapy: Development and Therapeutic Potential. J Med Chem 2022; 65:10133-10160. [PMID: 35878418 DOI: 10.1021/acs.jmedchem.2c00614] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Polo-like kinase 1 (PLK1) plays an important role in a variety of cellular functions, including the regulation of mitosis, DNA replication, autophagy, and the epithelial-mesenchymal transition (EMT). PLK1 overexpression is often associated with cell proliferation and poor prognosis in cancer patients, making it a promising antitumor target. To date, at least 10 PLK1 inhibitors (PLK1i) have been entered into clinical trials, among which the typical kinase domain (KD) inhibitor BI 6727 (volasertib) was granted "breakthrough therapy designation" by the FDA in 2013. Unfortunately, many other KD inhibitors showed poor specificity, resulting in dose-limiting toxicity, which has greatly impeded their development. Researchers recently discovered many PLK1i with higher selectivity, stronger potency, and better absorption, distribution, metabolism, and elimination (ADME) characteristics. In this review, we emphasize the structure-activity relationships (SARs) of PLK1i, providing insights into new drugs targeting PLK1 for antitumor clinical practice.
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Affiliation(s)
- Jifa Zhang
- Targeted Tracer Research and Development Laboratory, Institute of Respiratory Health, Frontiers Science Center for Disease-related Molecular Network, Joint Research Institution of Altitude Health, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China.,State Key Laboratory of Biotherapy and Cancer Center, Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
| | - Lele Zhang
- Targeted Tracer Research and Development Laboratory, Institute of Respiratory Health, Frontiers Science Center for Disease-related Molecular Network, Joint Research Institution of Altitude Health, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China.,State Key Laboratory of Biotherapy and Cancer Center, Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
| | - Jiaxing Wang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis 38163, Tennessee, United States
| | - Liang Ouyang
- Targeted Tracer Research and Development Laboratory, Institute of Respiratory Health, Frontiers Science Center for Disease-related Molecular Network, Joint Research Institution of Altitude Health, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China.,State Key Laboratory of Biotherapy and Cancer Center, Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
| | - Yuxi Wang
- Targeted Tracer Research and Development Laboratory, Institute of Respiratory Health, Frontiers Science Center for Disease-related Molecular Network, Joint Research Institution of Altitude Health, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China.,State Key Laboratory of Biotherapy and Cancer Center, Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
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Alverez CN, Park JE, Toti KS, Xia Y, Krausz KW, Rai G, Bang JK, Gonzalez FJ, Jacobson KA, Lee KS. Identification of a New Heterocyclic Scaffold for Inhibitors of the Polo-Box Domain of Polo-like Kinase 1. J Med Chem 2020; 63:14087-14117. [PMID: 33175530 PMCID: PMC7769008 DOI: 10.1021/acs.jmedchem.0c01669] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
As a mitotic-specific target widely deregulated in various human cancers, polo-like kinase 1 (Plk1) has been extensively explored for anticancer activity and drug discovery. Although multiple catalytic domain inhibitors were tested in preclinical and clinical studies, their efficacies are limited by dose-limiting cytotoxicity, mainly from off-target cross reactivity. The C-terminal noncatalytic polo-box domain (PBD) of Plk1 has emerged as an attractive target for generating new protein-protein interaction inhibitors. Here, we identified a 1-thioxo-2,4-dihydro-[1,2,4]triazolo[4,3-a]quinazolin-5(1H)-one scaffold that efficiently inhibits Plk1 PBD but not its related Plk2 and Plk3 PBDs. Structure-activity relationship studies led to multiple inhibitors having ≥10-fold higher inhibitory activity than the previously characterized Plk1 PBD-specific phosphopeptide, PLHSpT (Kd ∼ 450 nM). In addition, S-methyl prodrugs effectively inhibited mitotic progression and cell proliferation and their metabolic stability was determined. These data describe a novel class of small-molecule inhibitors that offer a promising avenue for future drug discovery against Plk1-addicted cancers.
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Affiliation(s)
- Celeste N Alverez
- Chemistry Section, Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850, United States
| | - Jung-Eun Park
- Chemistry Section, Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Kiran S Toti
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Yangliu Xia
- Chemistry Section, Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Kristopher W Krausz
- Chemistry Section, Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Ganesha Rai
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850, United States
| | - Jeong K Bang
- Division of Magnetic Resonance, Korea Basic Science Institute, Cheongju 28119, Republic of Korea
| | - Frank J Gonzalez
- Chemistry Section, Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Kyung S Lee
- Chemistry Section, Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
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5
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Park JE, Hymel D, Burke TR, Lee KS. Current progress and future perspectives in the development of anti-polo-like kinase 1 therapeutic agents. F1000Res 2017; 6:1024. [PMID: 28721210 PMCID: PMC5497816 DOI: 10.12688/f1000research.11398.1] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/23/2017] [Indexed: 12/21/2022] Open
Abstract
Although significant levels of side effects are often associated with their use, microtubule-directed agents that primarily target fast-growing mitotic cells have been considered to be some of the most effective anti-cancer therapeutics. With the hope of developing new-generation anti-mitotic agents with reduced side effects and enhanced tumor specificity, researchers have targeted various proteins whose functions are critically required for mitotic progression. As one of the highly attractive mitotic targets, polo-like kinase 1 (Plk1) has been the subject of an extensive effort for anti-cancer drug discovery. To date, a variety of anti-Plk1 agents have been developed, and several of them are presently in clinical trials. Here, we will discuss the current status of generating anti-Plk1 agents as well as future strategies for designing and developing more efficacious anti-Plk1 therapeutics.
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Affiliation(s)
- Jung-Eun Park
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - David Hymel
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD, 21702, USA
| | - Terrence R Burke
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD, 21702, USA
| | - Kyung S Lee
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
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6
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Kim TG, Lee JH, Lee MY, Kim KU, Lee JH, Park CH, Lee BH, Oh KS. Development of a High-Throughput Assay for Inhibitors of the Polo-Box Domain of Polo-Like Kinase 1 Based on Time-Resolved Fluorescence Energy Transfer. Biol Pharm Bull 2017; 40:1454-1462. [PMID: 28867728 DOI: 10.1248/bpb.b17-00283] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although enzyme-linked immunosorbent assay (ELISA) technology has been widely accepted for binding assays against the polo-box domain (PBD) of polo-like kinase-1 (Plk1), these assays have a limitation-related heterogeneous procedure, such as multiple incubations and washing steps to apply high-throughput screenings (HTSs). In the present study, a Plk1-PBD binding assay based on time-resolved fluorescence energy transfer (TR-FRET) was developed for HTS of PBD-binding inhibitors. The TR-FRET-based Plk1-PBD binding assay is sensitive and robust and can be miniaturized into the 384-well plate-based format. Compared with the ELISA-based Plk1-PBD binding assay (Z' factor, 0.53; signal-to-background ratio, 4.19), the TR-FRET-based Plk1-PBD binding assay improved the Z' factor (0.72) and signal-to-background ratio (8.16). Using TR-FRET based Plk1-PBD binding assay, pilot library screening of 1019 natural compounds was conducted and five hit compounds such as haematoxylin, verbascoside, menadione, lithospermic acid and (1,3-dioxolo[4,5-g]isoquinolinium 5,6,7,8-tetrahydro-4-methoxy-6,6-dimethyl-5-[2-oxo-2-(2-pyridinyl)ethyl]-iodide) (DITMD) were identified as Plk1-PBD inhibitor. In a functional assay to validate the hit compounds, five hit compounds exhibited suppression of HeLa cells proliferation. These results suggest that TR-FRET-based Plk1-PBD binding assay can be applied for an efficient and less time-consuming HTS of compound libraries.
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Affiliation(s)
- Tae Gi Kim
- Bio-Organic Science Division, Korea Research Institute of Chemical Technology
- Graduate School of New Drug Discovery and Development, Chungnam National University
| | - Ju Hee Lee
- Bio-Organic Science Division, Korea Research Institute of Chemical Technology
| | - Mi Young Lee
- Bio-Organic Science Division, Korea Research Institute of Chemical Technology
| | - Ka-Ul Kim
- Bio-Organic Science Division, Korea Research Institute of Chemical Technology
- Department of Medicinal and Pharmaceutical Chemistry, University of Science and Technology
| | - Jeong Hyun Lee
- Bio-Organic Science Division, Korea Research Institute of Chemical Technology
- Department of Medicinal and Pharmaceutical Chemistry, University of Science and Technology
| | - Chi Hoon Park
- Bio-Organic Science Division, Korea Research Institute of Chemical Technology
- Department of Medicinal and Pharmaceutical Chemistry, University of Science and Technology
| | - Byung Ho Lee
- Bio-Organic Science Division, Korea Research Institute of Chemical Technology
- Graduate School of New Drug Discovery and Development, Chungnam National University
| | - Kwang-Seok Oh
- Bio-Organic Science Division, Korea Research Institute of Chemical Technology
- Department of Medicinal and Pharmaceutical Chemistry, University of Science and Technology
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7
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Normandin K, Lavallée JF, Futter M, Beautrait A, Duchaine J, Guiral S, Marinier A, Archambault V. Identification of Polo-like kinase 1 interaction inhibitors using a novel cell-based assay. Sci Rep 2016; 5:37581. [PMID: 27874094 PMCID: PMC5118709 DOI: 10.1038/srep37581] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 10/31/2016] [Indexed: 02/08/2023] Open
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.
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Affiliation(s)
- Karine Normandin
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada
| | - Jean-François Lavallée
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada
| | - Marie Futter
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada
| | - Alexandre Beautrait
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada
| | - Jean Duchaine
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada
| | - Sébastien Guiral
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada
| | - Anne Marinier
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada
- Département de chimie, Université de Montréal, Montréal, Canada
| | - Vincent Archambault
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada
- Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, Canada
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8
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Park JE, Kim TS, Meng L, Bang JK, Kim BY, Lee KS. Putting a bit into the polo-box domain of polo-like kinase 1. J Anal Sci Technol 2015; 6:27. [PMID: 26500787 PMCID: PMC4610673 DOI: 10.1186/s40543-015-0069-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 09/27/2015] [Indexed: 01/11/2023] Open
Abstract
Polo-like kinase 1 (Plk1) plays key roles in regulating various mitotic processes that are critical for cellular proliferation. A growing body of evidence suggests that Plk1 overexpression is tightly associated with the development of human cancers. Interestingly, various types of cancer cells are shown to be addicted to a high level of Plk1, and the reversal of Plk1 addiction appears to be an effective strategy for selectively killing cancer cells, but not normal cells. Therefore, Plk1 is considered an attractive anticancer drug target. Over the years, a large number of inhibitors that target the catalytic activity of Plk1 have been developed. However, these inhibitors exhibit significant levels of cross-reactivity with related kinases, including Plk2 and Plk3. Consequently, as an alternative approach for developing anti-Plk1 therapeutics, substantial effort is under way to develop inhibitors that target the C-terminal protein–protein interaction domain of Plk1, called the polo-box domain (PBD). In this communication, I will discuss the pros and cons of targeting the PBD in comparison to those of targeting the ATP-binding site within the kinase domain.
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Affiliation(s)
- Jung-Eun Park
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 9000 Rockville Pike, Building 37, Room 3118, Bethesda, MD 20892 USA
| | - Tae-Sung Kim
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 9000 Rockville Pike, Building 37, Room 3118, Bethesda, MD 20892 USA
| | - Lingjun Meng
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 9000 Rockville Pike, Building 37, Room 3118, Bethesda, MD 20892 USA
| | - Jeong K Bang
- Division of Magnetic Resonance, Korea Basic Science Institute, 804-1, Yangcheong Ri, Ochang, 363-883 Chungbuk Republic of Korea
| | - Bo Y Kim
- World Class Institute, Korea Research Institute of Bioscience and Biotechnology, Ochang, 363-883 Republic of Korea
| | - Kyung S Lee
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 9000 Rockville Pike, Building 37, Room 3118, Bethesda, MD 20892 USA
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