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Kao CC, Kung PH, Tai CJ, Tsai MC, Cheng YB, Wu CC. Juglone prevents human platelet aggregation through inhibiting Akt and protein disulfide isomerase. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2021; 82:153449. [PMID: 33387969 DOI: 10.1016/j.phymed.2020.153449] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/24/2020] [Accepted: 12/22/2020] [Indexed: 06/12/2023]
Abstract
BACKGROUND/PURPOSE Juglone, a natural compound widely found in Juglandaceae plants, has been suggested as a potential drug candidate for treating cancer, inflammation, and diabetic vascular complications. In the present study, the antiplatelet effect and underlying mechanisms of juglone were investigated for the first time. STUDY DESIGN/METHODS Human platelet aggregation and activation were measured by turbidimetric aggregometry, flow cytometry, and Western blotting. In vitro antithrombotic activity of juglone was assessed using collagen-coated flow chambers under whole-blood flow conditions. The effect of juglone on protein disulfide isomerase (PDI) activity was determined by the dieosin glutathione disulfide assay. RESULTS Juglone (1 - 5 μM) inhibited platelet aggregation and glycoprotein (GP) IIb/IIIa activation caused by various agonists. In a whole blood flow chamber system, juglone reduced thrombus formation on collagen-coated surfaces under arterial shear rates. Juglone abolished intracellular Ca2+ elevation and protein kinase C activation caused by collagen, but had no significant effect on that induced by G protein-coupled receptor agonists. In contrast, Akt activation caused by various agonists were inhibited in juglone-treated platelets. Additionally, juglone showed inhibitory effects on both recombinant human PDI and platelet surface PDI at concentrations similar to those needed to prevent platelet aggregation. CONCLUSION Juglone exhibits potent in vitro antiplatelet and antithrombotic effects that are associated with inhibition of Akt activation and platelet surface PDI activity.
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Affiliation(s)
- Ching-Chieh Kao
- Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Po-Hsiung Kung
- Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Chi-Jung Tai
- Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Family Medicine, Pingtung Hospital, Ministry of Health and Welfare, Pingtung, Taiwan
| | - Meng-Chun Tsai
- Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Yuan-Bin Cheng
- Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Chin-Chung Wu
- Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung, Taiwan; Drug Development and Value Creation Research Center, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
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Lin YC, Ko YC, Hung SC, Lin YT, Lee JH, Tsai JY, Kung PH, Tsai MC, Chen YF, Wu CC. Selective Inhibition of PAR4 (Protease-Activated Receptor 4)-Mediated Platelet Activation by a Synthetic Nonanticoagulant Heparin Analog. Arterioscler Thromb Vasc Biol 2020; 39:694-703. [PMID: 30727756 DOI: 10.1161/atvbaha.118.311758] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective- PAR4 (protease-activated receptor 4), one of the thrombin receptors in human platelets, has emerged as a promising target for the treatment of arterial thrombotic disease. Previous studies implied that thrombin exosite II, known as a binding site for heparin, may be involved in thrombin-induced PAR4 activation. In the present study, a heparin octasaccharide analog containing the thrombin exosite II-binding domain of heparin was chemically synthesized and investigated for anti-PAR4 effect. Approach and Results- PAR4-mediated platelet aggregation was examined using either thrombin in the presence of a PAR1 antagonist or γ-thrombin, which selectively activates PAR4. SCH-28 specifically inhibits PAR4-mediated platelet aggregation, as well as the signaling events downstream of PAR4 in response to thrombin. Moreover, SCH-28 prevents thrombin-induced β-arrestin recruitment to PAR4 but not PAR1 in Chinese Hamster Ovary-K1 cells using a commercial enzymatic complementation assay. Compared with heparin, SCH-28 is more potent in inhibiting PAR4-mediated platelet aggregation but has no significant anticoagulant activity. In an in vitro thrombosis model, SCH-28 reduces thrombus formation under whole blood arterial flow conditions. Conclusions- SCH-28, a synthetic small-molecular and nonanticoagulant heparin analog, inhibits thrombin-induced PAR4 activation by interfering with thrombin exosite II, a mechanism of action distinct from other PAR4 inhibitors that target the receptor. The characteristics of SCH-28 provide a new strategy for targeting PAR4 with the potential for the treatment of arterial thrombosis.
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Affiliation(s)
- Yu-Chuan Lin
- From the Graduate Institute of Natural Products (Y.-C.L., J.-H.L., J.-Y.T., P.-H.K., M.-C.T., Y.-F.C., C.-C.W.), Kaohsiung Medical University, Taiwan
| | - Yen-Chun Ko
- Genomics Research Center, Academia Sinica, Taipei, Taiwan (Y.-C.K., S.-C.H.)
| | - Shang-Cheng Hung
- Genomics Research Center, Academia Sinica, Taipei, Taiwan (Y.-C.K., S.-C.H.)
| | - Ying-Ting Lin
- Department of Biotechnology, College of Life Science (Y.-T.L., J.-H.L.), Kaohsiung Medical University, Taiwan
| | - Jia-Hau Lee
- From the Graduate Institute of Natural Products (Y.-C.L., J.-H.L., J.-Y.T., P.-H.K., M.-C.T., Y.-F.C., C.-C.W.), Kaohsiung Medical University, Taiwan.,Department of Biotechnology, College of Life Science (Y.-T.L., J.-H.L.), Kaohsiung Medical University, Taiwan
| | - Ju-Ying Tsai
- From the Graduate Institute of Natural Products (Y.-C.L., J.-H.L., J.-Y.T., P.-H.K., M.-C.T., Y.-F.C., C.-C.W.), Kaohsiung Medical University, Taiwan
| | - Po-Hsiung Kung
- From the Graduate Institute of Natural Products (Y.-C.L., J.-H.L., J.-Y.T., P.-H.K., M.-C.T., Y.-F.C., C.-C.W.), Kaohsiung Medical University, Taiwan
| | - Meng-Chun Tsai
- From the Graduate Institute of Natural Products (Y.-C.L., J.-H.L., J.-Y.T., P.-H.K., M.-C.T., Y.-F.C., C.-C.W.), Kaohsiung Medical University, Taiwan
| | - Yih-Fung Chen
- From the Graduate Institute of Natural Products (Y.-C.L., J.-H.L., J.-Y.T., P.-H.K., M.-C.T., Y.-F.C., C.-C.W.), Kaohsiung Medical University, Taiwan
| | - Chin-Chung Wu
- From the Graduate Institute of Natural Products (Y.-C.L., J.-H.L., J.-Y.T., P.-H.K., M.-C.T., Y.-F.C., C.-C.W.), Kaohsiung Medical University, Taiwan.,Department of Medical Research, Kaohsiung Medical University Hospital, Taiwan (C.-C.W.).,Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung, Taiwan (C.-C.W.)
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Ganesan K, Xu B. Telomerase Inhibitors from Natural Products and Their Anticancer Potential. Int J Mol Sci 2017; 19:ijms19010013. [PMID: 29267203 PMCID: PMC5795965 DOI: 10.3390/ijms19010013] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 12/10/2017] [Accepted: 12/19/2017] [Indexed: 12/25/2022] Open
Abstract
Telomeres and telomerase are nowadays exploring traits on targets for anticancer therapy. Telomerase is a unique reverse transcriptase enzyme, considered as a primary factor in almost all cancer cells, which is mainly responsible to regulate the telomere length. Hence, telomerase ensures the indefinite cell proliferation during malignancy—a hallmark of cancer—and this distinctive feature has provided telomerase as the preferred target for drug development in cancer therapy. Deactivation of telomerase and telomere destabilization by natural products provides an opening to succeed new targets for cancer therapy. This review aims to provide a fundamental knowledge for research on telomere, working regulation of telomerase and its various binding proteins to inhibit the telomere/telomerase complex. In addition, the review summarizes the inhibitors of the enzyme catalytic subunit and RNA component, natural products that target telomeres, and suppression of transcriptional and post-transcriptional levels. This extensive understanding of telomerase biology will provide indispensable information for enhancing the efficiency of rational anti-cancer drug design.
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Affiliation(s)
- Kumar Ganesan
- Food Science and Technology Program, Beijing Normal University-Hong Kong Baptist University United International College, Zhuhai 519087, China.
| | - Baojun Xu
- Food Science and Technology Program, Beijing Normal University-Hong Kong Baptist University United International College, Zhuhai 519087, China.
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Honokiol suppresses formyl peptide-induced human neutrophil activation by blocking formyl peptide receptor 1. Sci Rep 2017; 7:6718. [PMID: 28751674 PMCID: PMC5532207 DOI: 10.1038/s41598-017-07131-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 06/23/2017] [Indexed: 11/24/2022] Open
Abstract
Formyl peptide receptor 1 (FPR1) mediates bacterial and mitochondrial N-formyl peptides-induced neutrophil activation. Therefore, FPR1 is an important therapeutic target for drugs to treat septic or sterile inflammatory diseases. Honokiol, a major bioactive compound of Magnoliaceae plants, possesses several anti-inflammatory activities. Here, we show that honokiol exhibits an inhibitory effect on FPR1 binding in human neutrophils. Honokiol inhibited superoxide anion generation, reactive oxygen species formation, and elastase release in bacterial or mitochondrial N-formyl peptides (FPR1 agonists)-activated human neutrophils. Adhesion of FPR1-induced human neutrophils to cerebral endothelial cells was also reduced by honokiol. The receptor-binding results revealed that honokiol repressed FPR1-specific ligand N-formyl-Nle-Leu-Phe-Nle-Tyr-Lys-fluorescein binding to FPR1 in human neutrophils, neutrophil-like THP-1 cells, and hFPR1-transfected HEK293 cells. However, honokiol did not inhibit FPR2-specific ligand binding to FPR2 in human neutrophils. Furthermore, honokiol inhibited FPR1 agonist-induced calcium mobilization as well as phosphorylation of p38 MAPK, ERK, and JNK in human neutrophils. In conclusion, our data demonstrate that honokiol may have therapeutic potential for treating FPR1-mediated inflammatory diseases.
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Kung PH, Hsieh PW, Lin YT, Lee JH, Chen IH, Wu CC. HPW-RX40 prevents human platelet activation by attenuating cell surface protein disulfide isomerases. Redox Biol 2017; 13:266-277. [PMID: 28600983 PMCID: PMC5466588 DOI: 10.1016/j.redox.2017.05.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/22/2017] [Accepted: 05/25/2017] [Indexed: 01/01/2023] Open
Abstract
Protein disulfide isomerase (PDI) present at platelet surfaces has been considered to play an important role in the conformational change and activation of the integrin glycoprotein IIb/IIIa (GPIIb/IIIa) and thus enhances platelet aggregation. Growing evidences indicated that platelet surface PDI may serve as a potential target for developing of a new class of antithrombotic agents. In the present study, we investigated the effects of HPW-RX40, a chemical derivative of β-nitrostyrene, on platelet activation and PDI activity. HPW-RX40 inhibited platelet aggregation, GPIIb/IIIa activation, and P-selectin expression in human platelets. Moreover, HPW-RX40 reduced thrombus formation in human whole blood under flow conditions, and protects mice from FeCl3-induced carotid artery occlusion. HPW-RX40 inhibited the activity of recombinant PDI family proteins (PDI, ERp57, and ERp5) as well as suppressed cell surface PDI activity of platelets in a reversible manner. Exogenous addition of PDI attenuated the inhibitory effect of HPW-RX40 on GPIIb/IIIa activation. Structure-based molecular docking simulations indicated that HPW-RX40 binds to the active site of PDI by forming hydrogen bonds. In addition, HPW-RX40 neither affected the cell viability nor induced endoplasmic reticulum stress in human cancer A549 and MDA-MB-231 cells. Taken together, our results suggest that HPW-RX40 is a reversible and non-cytotoxic PDI inhibitor with antiplatelet effects, and it may have a potential for development of novel antithrombotic agents.
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Affiliation(s)
- Po-Hsiung Kung
- Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Pei-Wen Hsieh
- Graduate Institute of Natural Products, School of Traditional Chinese Medicine, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Department of Anesthesiology, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Ying-Ting Lin
- Department of Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Jia-Hau Lee
- Department of Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - I-Hua Chen
- Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Chin-Chung Wu
- Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung, Taiwan.
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Tsai JY, Rédei D, Forgo P, Li Y, Vasas A, Hohmann J, Wu CC. Isolation of Phorbol Esters from Euphorbia grandicornis and Evaluation of Protein Kinase C- and Human Platelet-Activating Effects of Euphorbiaceae Diterpenes. JOURNAL OF NATURAL PRODUCTS 2016; 79:2658-2666. [PMID: 27731641 DOI: 10.1021/acs.jnatprod.6b00603] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Human platelets contain conventional (α and β) and novel isoforms of PKC (δ and θ), and PKC activation can result in platelet aggregation and secretion reaction that are important for thrombus formation. Several tumor-promoting Euphorbiaceae diterpenes are known to act as direct activators of PKC, but many types of such diterpenes have not been studied as platelet stimulators. In the present study, two new and five known phorbol esters were isolated from Euphorbia grandicornis. Two of the isolated phorbol esters together with compounds representing ingenane, jatrophane, and myrsinane structural types were studied on PKC activation and platelet stimulation. The investigated phorbol esters and ingenane esters induced blood platelet aggregation and ATP secretion. PKC activation was demonstrated by inducing membrane translocation of PKCs, phosphorylation of PKC substrates, and activation of PKC signaling pathways. The PKC-activating effect of the compounds correlated well with their efficacy to cause platelet stimulation. Moreover, by using an isoform-specific PKC inhibitor, it was found that besides conventional PKCs novel PKCs also play a positive role in platelet activation caused by phorbol/ingenane esters, especially in regulating platelet aggregation. The present results suggest that platelets afford a useful model for studying PKC activators of natural origin or their chemical derivatives.
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Affiliation(s)
- Ju-Ying Tsai
- Graduate Institute of Natural Products and ‡Research Center for Natural Products and Drug Development, Kaohsiung Medical University , Kaohsiung 807, Taiwan
- Department of Pharmacognosy and ⊥Interdisciplinary Centre for Natural Products, University of Szeged , Eötvös u. 6, H-6720 Szeged, Hungary
| | - Dóra Rédei
- Graduate Institute of Natural Products and ‡Research Center for Natural Products and Drug Development, Kaohsiung Medical University , Kaohsiung 807, Taiwan
- Department of Pharmacognosy and ⊥Interdisciplinary Centre for Natural Products, University of Szeged , Eötvös u. 6, H-6720 Szeged, Hungary
| | - Peter Forgo
- Graduate Institute of Natural Products and ‡Research Center for Natural Products and Drug Development, Kaohsiung Medical University , Kaohsiung 807, Taiwan
- Department of Pharmacognosy and ⊥Interdisciplinary Centre for Natural Products, University of Szeged , Eötvös u. 6, H-6720 Szeged, Hungary
| | - Yu Li
- Graduate Institute of Natural Products and ‡Research Center for Natural Products and Drug Development, Kaohsiung Medical University , Kaohsiung 807, Taiwan
- Department of Pharmacognosy and ⊥Interdisciplinary Centre for Natural Products, University of Szeged , Eötvös u. 6, H-6720 Szeged, Hungary
| | - Andrea Vasas
- Graduate Institute of Natural Products and ‡Research Center for Natural Products and Drug Development, Kaohsiung Medical University , Kaohsiung 807, Taiwan
- Department of Pharmacognosy and ⊥Interdisciplinary Centre for Natural Products, University of Szeged , Eötvös u. 6, H-6720 Szeged, Hungary
| | - Judit Hohmann
- Graduate Institute of Natural Products and ‡Research Center for Natural Products and Drug Development, Kaohsiung Medical University , Kaohsiung 807, Taiwan
- Department of Pharmacognosy and ⊥Interdisciplinary Centre for Natural Products, University of Szeged , Eötvös u. 6, H-6720 Szeged, Hungary
| | - Chin-Chung Wu
- Graduate Institute of Natural Products and ‡Research Center for Natural Products and Drug Development, Kaohsiung Medical University , Kaohsiung 807, Taiwan
- Department of Pharmacognosy and ⊥Interdisciplinary Centre for Natural Products, University of Szeged , Eötvös u. 6, H-6720 Szeged, Hungary
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