1
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Rousseau A, Vincent G, Kouklovsky C. Preparation of an advanced intermediate for the synthesis of leustroducsins and phoslactomycins by heterocycloaddition. Beilstein J Org Chem 2022; 18:1385-1395. [PMID: 36262671 PMCID: PMC9551206 DOI: 10.3762/bjoc.18.143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 09/23/2022] [Indexed: 11/23/2022] Open
Abstract
A convergent strategy for the synthesis of leustroducsins and phoslactomycins has been designed, relying on the synthesis and the coupling of three main fragments. The central fragment was synthesized via a regio-and stereoselective nitroso Diels–Alder reaction with an enol phosphate, followed by reductive cleavage of the phosphate to the ketone 11b. Coupling studies of this fragment with the lactone fragment was accomplished in a stereoselective fashion through a vinyllithium intermediate. An advanced synthetic intermediate was then obtained after functional group transformation.
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Affiliation(s)
- Anaïs Rousseau
- Institut de Chimie Moléculaire et des Matériaux d’Orsay, Université Paris-Saclay, CNRS, F-91405 Orsay, France
| | - Guillaume Vincent
- Institut de Chimie Moléculaire et des Matériaux d’Orsay, Université Paris-Saclay, CNRS, F-91405 Orsay, France
| | - Cyrille Kouklovsky
- Institut de Chimie Moléculaire et des Matériaux d’Orsay, Université Paris-Saclay, CNRS, F-91405 Orsay, France
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2
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Güleç Alagöz L, Çalışkan A. Intraoral Repair of Dental Restorations with Resin Composite. CYPRUS JOURNAL OF MEDICAL SCIENCES 2022. [DOI: 10.4274/cjms.2020.2779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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3
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Della-Felice F, de Andrade Bartolomeu A, Pilli RA. The phosphate ester group in secondary metabolites. Nat Prod Rep 2022; 39:1066-1107. [PMID: 35420073 DOI: 10.1039/d1np00078k] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Covering: 2000 to mid-2021The phosphate ester is a versatile, widespread functional group involved in a plethora of biological activities. Its presence in secondary metabolites, however, is relatively rare compared to other functionalities and thus is part of a rather unexplored chemical space. Herein, the chemistry of secondary metabolites containing the phosphate ester group is discussed. The text emphasizes their structural diversity, biological and pharmacological profiles, and synthetic approaches employed in the phosphorylation step during total synthesis campaigns, covering the literature from 2000 to mid-2021.
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Affiliation(s)
- Franco Della-Felice
- Institute of Chemistry, University of Campinas (UNICAMP), P.O. Box 6154, CEP 13083-970 Campinas, Sao Paulo, Brazil.,Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007 Tarragona, Spain.
| | | | - Ronaldo Aloise Pilli
- Institute of Chemistry, University of Campinas (UNICAMP), P.O. Box 6154, CEP 13083-970 Campinas, Sao Paulo, Brazil
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4
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The potent protein phosphatase 2A inhibitors aminocytostatins: new derivatives of cytostatin. J Antibiot (Tokyo) 2021; 74:743-751. [PMID: 34290381 DOI: 10.1038/s41429-021-00455-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/07/2021] [Accepted: 06/07/2021] [Indexed: 02/06/2023]
Abstract
Specific inhibitors of protein phosphatase 2A (PP2A) mediate anticancer effects by augmenting the tumor-killing activity of natural killer (NK) cells. In this study, new PP2A inhibitors, aminocytostatins A-E, were isolated from Kitasatospora sp. MJ654-NF4 and structurally characterized. Aminocytostatins are derivatives of cytostatin, which is a specific PP2A inhibitor isolated from the same organism, and aminocytostatins have a characteristic amino group within the lactone moiety. Compared to cytostatin, aminocytostatin A showed a stronger inhibitory activity against PP2A in vitro and augmented the tumor-killing activity of NK cells in vivo. Furthermore, a docking model was generated to demonstrate the favorable activities of aminocytostatin A.
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5
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Anti-Metastatic Activity of an Anti-EGFR Monoclonal Antibody against Metastatic Colorectal Cancer with KRAS p.G13D Mutation. Int J Mol Sci 2020; 21:ijms21176037. [PMID: 32839411 PMCID: PMC7504481 DOI: 10.3390/ijms21176037] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 08/12/2020] [Accepted: 08/20/2020] [Indexed: 12/11/2022] Open
Abstract
The now clinically-used anti-epidermal growth factor receptor (EGFR) monoclonal antibodies have demonstrated significant efficacy only in patients with metastatic colorectal cancer (mCRC), with wild-type Kirsten rat sarcoma viral oncogene homolog (KRAS). However, no effective treatments for patients with mCRC with KRAS mutated tumors have been approved yet. Therefore, a new strategy for targeting mCRC with KRAS mutated tumors is desired. In the present study, we examined the anti-tumor activities of a novel anti-EGFR monoclonal antibody, EMab-17 (mouse IgG2a, kappa), in colorectal cancer (CRC) cells with the KRAS p.G13D mutation. This antibody recognized endogenous EGRF in CRC cells with or without KRAS mutations, and showed a high sensitivity for CRC cells in flow cytometry, indicating that EMab-17 possesses a high binding affinity to the endogenous EGFR. In vitro experiments showed that EMab-17 exhibited antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity activities against CRC cells. In vivo analysis revealed that EMab-17 inhibited the metastases of HCT-15 and HCT-116 cells in the livers of nude mouse metastatic models, unlike the anti-EGFR monoclonal antibody EMab-51 of subtype mouse IgG1. In conclusion, EMab-17 may be useful in an antibody-based therapy against mCRC with the KRAS p.G13D mutation.
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6
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Zunyimycin C inhibits the proliferation of lung cancer cells by inducing apoptosis through an AKT-related mechanism. Med Chem Res 2019. [DOI: 10.1007/s00044-019-02417-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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7
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Raman D, Pervaiz S. Redox inhibition of protein phosphatase PP2A: Potential implications in oncogenesis and its progression. Redox Biol 2019; 27:101105. [PMID: 30686777 PMCID: PMC6859563 DOI: 10.1016/j.redox.2019.101105] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 01/04/2019] [Accepted: 01/09/2019] [Indexed: 01/17/2023] Open
Abstract
Cellular processes are dictated by the active signaling of proteins relaying messages to regulate cell proliferation, apoptosis, signal transduction and cell communications. An intricate web of protein kinases and phosphatases are critical to the proper transmission of signals across such cascades. By governing 30–50% of all protein dephosphorylation in the cell, with prominent substrate proteins being key regulators of signaling cascades, the phosphatase PP2A has emerged as a celebrated player in various developmental and tumorigenic pathways, thereby posing as an attractive target for therapeutic intervention in various pathologies wherein its activity is deregulated. This review is mainly focused on refreshing our understanding of the structural and functional complexity that cocoons the PP2A phosphatase, and its expression in cancers. Additionally, we focus on its physiological regulation as well as into recent advents and strategies that have shown promise in countering the deregulation of the phosphatase through its targeted reactivation. Finally, we dwell upon one of the key regulators of PP2A in cancer cells-cellular redox status-its multifarious nature, and its integration into the reactome of PP2A, highlighting some of the significant impacts that ROS can inflict on the structural modifications and functional aspect of PP2A.
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Affiliation(s)
- Deepika Raman
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Shazib Pervaiz
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Medical Science Cluster Cancer Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; National University Cancer Institute, National University Health System, Singapore, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore.
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8
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Immunometabolism of T cells and NK cells: metabolic control of effector and regulatory function. Inflamm Res 2018; 67:813-828. [PMID: 30066126 DOI: 10.1007/s00011-018-1174-3] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 07/24/2018] [Accepted: 07/26/2018] [Indexed: 01/10/2023] Open
Abstract
Metabolic flux can dictate cell fate, including immune cell effector and regulatory function. The metabolic regulation of cell function is well characterized with respect to effector, memory, and regulatory T cells. This knowledge may allow for manipulation of T cell metabolic pathways that set the stage for more effective T cell therapy. Natural Killer (NK) and T-lymphocytes have complementary roles in the defense against pathogens. However, studies of NK cell metabolism are only beginning to emerge and there is comparatively little knowledge on the metabolic regulation of NK-cell activation and effector function. Given their common lymphoid lineage, effector functions and cellular memory potential our current knowledge on T cell metabolism could inform investigation of metabolic reprogramming in NK cells. In this review, we compare the current knowledge of metabolic regulation in T cell and NK cell development, activation, effector and memory function. Commonalties in glucose transport, hypoxia-inducible factors and mTOR highlight metabolic control points in both cells types. Contrasting the glycolytic and oxidative nodes of metabolic regulation in T cells versus NK cells may provide insight into the contribution of specific immune responses to disease and promote the development of immunotherapeutic approaches targeting both innate and adaptive immune responses.
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9
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Raghavan S, Patel JS. A Stereoselective Synthesis of the Carbon Backbone of Phoslactomycin B. European J Org Chem 2017. [DOI: 10.1002/ejoc.201700379] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Sadagopan Raghavan
- Natural Product Chemistry Division; Indian Institute of Chemical Technology; Hyderabad India
- Academy of Scientific and Innovative Research; Indian Institute of Chemical Technology; Hyderabad India
| | - Javed Sardar Patel
- Natural Product Chemistry Division; Indian Institute of Chemical Technology; Hyderabad India
- Academy of Scientific and Innovative Research; Indian Institute of Chemical Technology; Hyderabad India
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10
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A novel monoclonal antibody targeting coxsackie virus and adenovirus receptor inhibits tumor growth in vivo. Sci Rep 2017; 7:40400. [PMID: 28074864 PMCID: PMC5225458 DOI: 10.1038/srep40400] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 12/07/2016] [Indexed: 12/26/2022] Open
Abstract
To create a new anti-tumor antibody, we conducted signal sequence trap by retrovirus-meditated expression method and identified coxsackie virus and adenovirus receptor (CXADR) as an appropriate target. We developed monoclonal antibodies against human CXADR and found that one antibody (6G10A) significantly inhibited the growth of subcutaneous as well as orthotopic xenografts of human prostate cancer cells in vivo. Furthermore, 6G10A also inhibited other cancer xenografts expressing CXADR, such as pancreatic and colorectal cancer cells. Knockdown and overexpression of CXADR confirmed the dependence of its anti-tumor activity on CXADR expression. Our studies of its action demonstrated that 6G10A exerted its anti-tumor activity primarily through both antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity. Moreover, 6G10A reacted with human tumor tissues, such as prostate, lung, and brain, each of which express CXADR. Although we need further evaluation of its reactivity and safety in human tissues, our results show that a novel anti-CXADR antibody may be a feasible candidate for cancer immunotherapy.
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11
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Trost BM, Knopf JD, Brindle CS. Synthetic Strategies Employed for the Construction of Fostriecin and Related Natural Products. Chem Rev 2016; 116:15035-15088. [PMID: 28027648 PMCID: PMC5720176 DOI: 10.1021/acs.chemrev.6b00488] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Fostriecin and related natural products present a significant challenge for synthetic chemists due to their structural complexity and chemical sensitivity. This review will chronicle the successful efforts of synthetic chemists in the construction of these biologically active molecules. Key carbon-carbon bond forming reactions will be highlighted, as well as the methods used to install the numerous stereocenters present in this class of compounds.
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Affiliation(s)
- Barry M. Trost
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, United States
| | - Joshua D. Knopf
- Department of Chemistry, Trinity College, 300 Summit Street, Hartford, Connecticut 06106, United States
| | - Cheyenne S. Brindle
- Department of Chemistry, Trinity College, 300 Summit Street, Hartford, Connecticut 06106, United States
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12
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Trost BM, Biannic B, Brindle CS, O'Keefe BM, Hunter TJ, Ngai MY. A Highly Convergent Total Synthesis of Leustroducsin B. J Am Chem Soc 2015; 137:11594-7. [PMID: 26313159 PMCID: PMC4621997 DOI: 10.1021/jacs.5b07438] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Leustroducsin
B exhibits a large variety of biological activities
and unique structural features. An efficient and highly convergent
total synthesis of Leustroducsin B was achieved in 17 longest linear
and 39 total steps by disconnecting the molecule into three fragments
having similar levels of complexity. These pieces were connected via
a highly efficient chelate-controlled addition of a vinyl zincate
to an α-hydroxy ketone and a silicon-mediated cross-coupling.
The stereochemistry of the central and western fragments was set catalytically
in high yields and excellent de by a zinc-ProPhenol-catalyzed aldol
reaction and a palladium-catalyzed asymmetric allylic alkylation.
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Affiliation(s)
- Barry M Trost
- Department of Chemistry, Stanford University , Stanford, California 94305-5580, United States
| | - Berenger Biannic
- Department of Chemistry, Stanford University , Stanford, California 94305-5580, United States
| | - Cheyenne S Brindle
- Department of Chemistry, Stanford University , Stanford, California 94305-5580, United States
| | - B Michael O'Keefe
- Department of Chemistry, Stanford University , Stanford, California 94305-5580, United States
| | - Thomas J Hunter
- Department of Chemistry, Stanford University , Stanford, California 94305-5580, United States
| | - Ming-Yu Ngai
- Department of Chemistry, Stanford University , Stanford, California 94305-5580, United States
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13
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Fotso S, Graupner P, Xiong Q, Hahn D, Avila-Adame C, Davis G. Phoslactomycins from Streptomyces sp. MLA1839 and their biological activities. JOURNAL OF NATURAL PRODUCTS 2013; 76:1509-1513. [PMID: 23914940 DOI: 10.1021/np400232j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Phoslactomycins H (1) and I (2), two new members of the phoslactomycin class of chemistry, were isolated from Streptomyces sp. MLA1839 on the basis of their antifungal activities. Their structures were elucidated using extensive NMR spectroscopy and mass spectrometry. Phoslactomycin H (1) featured a rare and unprecedented N,N-dimethylamine substitution at C-4 and existed as a hydroxy acid rather than the more common lactone. Herein, we report the structure of these compounds and their biological activities.
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Affiliation(s)
- Serge Fotso
- Discovery Research, Dow AgroSciences , 9330 Zionsville Road, Indianapolis, Indiana 46268, USA.
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14
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Metastatic Lesions with and without Interleukin-18–Dependent Genes in Advanced-Stage Melanoma Patients. THE AMERICAN JOURNAL OF PATHOLOGY 2013; 183:69-82. [DOI: 10.1016/j.ajpath.2013.03.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 03/12/2013] [Accepted: 03/13/2013] [Indexed: 01/07/2023]
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15
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Abstract
Protein phosphatases of the type 2A family (PP2A) represent a major fraction of cellular Ser/Thr phosphatase activity in any given human tissue. In this review, we describe how the holoenzymic nature of PP2A and the existence of several distinct PP2A composing subunits allow for the generation of multiple structurally and functionally different PP2A complexes, explaining why PP2A is involved in the regulation of so many diverse cell biological and physiological processes. Moreover, in human disease, most notably in several cancers and Alzheimer's Disease, PP2A expression and/or activity have been found significantly decreased, underscoring its important functions as a major tumor suppressor and tau phosphatase. Hence, several recent preclinical studies have demonstrated that pharmacological restoration of PP2A activity, as well as pharmacological PP2A inhibition, under certain conditions, may be of significant future therapeutic value.
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16
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Chen YL, Zhao J, Liu W, Gao JF, Tao LM, Pan HX, Tang GL. Identification of phoslactomycin biosynthetic gene clusters from Streptomyces platensis SAM-0654 and characterization of PnR1 and PnR2 as positive transcriptional regulators. Gene 2012; 509:195-200. [PMID: 22940146 DOI: 10.1016/j.gene.2012.08.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 08/10/2012] [Accepted: 08/20/2012] [Indexed: 11/20/2022]
Abstract
Phoslactomycins (PLMs) are inhibitors of protein serine/threonine phosphatase 2A showing diverse and important antifungal, antibacterial and antitumor activity. PLMs are polyketide natural products and produced by several Streptomyces species. The PLMs biosynthetic gene clusters were identified from Streptomyces platensis SAM-0654 and localized in two separate genomic regions, consisting of 27 open reading frames that encode polyketide synthases (PKSs), enzymes for cyclohexanecarboxyl-CoA (CHC-CoA) and ethylmalonyl-CoA (Em-CoA) synthesis, enzymes for post-PKS modifications, proposed regulators, and putative resistance transporters. Bioinformatic analysis and inactivation experiment of regulatory genes suggest that PnR1 and PnR2 are two positive regulators of PLMs biosynthesis. Gene transcription analysis by reverse transcriptase PCR (RT-PCR) of the PLMs gene cluster demonstrated that PnR1 and PnR2 activate the transcription of the structural biosynthetic genes while PnR2 specially governs the transcription of pnR1 in a higher level.
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Affiliation(s)
- Yun-Liang Chen
- State Key Laboratory of Bio-organic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
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17
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Abstract
The ability of natural killer (NK) cells to kill malignant or infected cells depends on the integration of signals from different families of cell surface receptors, including cytokine receptors. How such signals then regulate NK-cell cytotoxicity is incompletely understood. Here we analyzed an endogenous inhibitor of protein phosphatase 2A (PP2A) activity called SET, and its role in regulating human NK-cell cytotoxicity and its mechanism of action in human NK cells. RNAi-mediated suppression of SET down-modulates NK-cell cytotoxicity, whereas ectopic overexpression of SET enhances cytotoxicity. SET knockdown inhibits both mRNA and protein granzyme B expression, as well as perforin expression, whereas SET overexpression enhances granzyme B expression. Treatment of NK cells with the PP2A activator 1,9-dideoxy-forskolin also inhibits both granzyme B expression and cytotoxicity. In addition, pretreatment with the PP2A inhibitor okadaic acid rescues declining granzyme B mRNA levels in SET knockdown cells. Down-modulation of SET expression or activation of PP2A also decreases human NK-cell antibody-dependent cellular cytotoxicity. Finally, the induction of granzyme B gene expression by interleukin-2 and interleukin-15 is inhibited by SET knockdown. These data provide evidence that granzyme B gene expression and therefore human NK-cell cytotoxicity can be regulated by the PP2A-SET interplay.
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18
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Druais V, Hall MJ, Corsi C, Wendeborn SV, Meyer C, Cossy J. A convergent approach toward phoslactomycins and leustroducsins. Tetrahedron 2010. [DOI: 10.1016/j.tet.2010.05.050] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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19
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Wada SI, Usami I, Umezawa Y, Inoue H, Ohba SI, Someno T, Kawada M, Ikeda D. Rubratoxin A specifically and potently inhibits protein phosphatase 2A and suppresses cancer metastasis. Cancer Sci 2010; 101:743-50. [PMID: 20028386 PMCID: PMC11158319 DOI: 10.1111/j.1349-7006.2009.01438.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Although cytostatin analog protein phosphatase 2A (PP2A)-specific inhibitors are promising candidates of a new type of anticancer drug, their development has been hindered because of their liability. To find new classes of PP2A-specific inhibitors, we conducted a screening with microbial metabolites and found that rubratoxin A, a classical mycotoxin, is a highly specific and potent inhibitor of the enzyme. While rubratoxin A inhibits PP2A at Ki = 28.7 nm, it hardly inhibited any other phosphatases examined. Rubratoxin B, a close analog, also specifically but weakly inhibits PP2A at Ki = 3.1 microM. The inhibition of intracellular PP2A in cultured cells is obviously observed with 20 microM rubratoxin A treatment for 3 h, inducing the overphosphorylation in PP2A substrate proteins. Although rubratoxins and cytostatin differ in the apparent structures, these compounds share similarities in the structures in detail and PP2A-binding manners. Rubratoxin A showed higher suppression of tumor metastasis and reduction of the primary tumor volume than cytostatin in mouse experiments. As a successor of cytostatin analogs, rubratoxin A should be a good compound leading to the development of antitumor drugs targeting PP2A.
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Affiliation(s)
- Shun-ichi Wada
- Numazu Bio-Medical Research Institute, Microbial Chemistry Research Foundation, Shizuoka
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20
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Swingle MR, Amable L, Lawhorn BG, Buck SB, Burke CP, Ratti P, Fischer KL, Boger DL, Honkanen RE. Structure-activity relationship studies of fostriecin, cytostatin, and key analogs, with PP1, PP2A, PP5, and( beta12-beta13)-chimeras (PP1/PP2A and PP5/PP2A), provide further insight into the inhibitory actions of fostriecin family inhibitors. J Pharmacol Exp Ther 2009; 331:45-53. [PMID: 19592665 PMCID: PMC2766224 DOI: 10.1124/jpet.109.155630] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Accepted: 07/08/2009] [Indexed: 01/29/2023] Open
Abstract
Fostriecin and cytostatin are structurally related natural inhibitors of serine/threonine phosphatases, with promising antitumor activity. The total synthesis of these antitumor agents has enabled the production of structural analogs, which are useful to explore the biological significance of features contained in the parent compounds. Here, the inhibitory activity of fostriecin, cytostatin, and 10 key structural analogs were tested in side-by-side phosphatase assays to further characterize their inhibitory activity against PP1c (Ser/Thr protein phosphatase 1 catalytic subunit), PP2Ac (Ser/Thr protein phosphatase 2A catalytic subunit), PP5c (Ser/Thr protein phosphatase 5 catalytic subunit), and chimeras of PP1 (Ser/Thr protein phosphatase 1) and PP5 (Ser/Thr protein phosphatase 5), in which key residues predicted for inhibitor contact with PP2A (Ser/Thr protein phosphatase 2A) were introduced into PP1 and PP5 using site-directed mutagenesis. The data confirm the importance of the C9-phosphate and C11-alcohol for general inhibition and further demonstrate the importance of a predicted C3 interaction with a unique cysteine (Cys(269)) in the beta12-beta13 loop of PP2A. The data also indicate that additional features beyond the unsaturated lactone contribute to inhibitory potency and selectivity. Notably, a derivative of fostriecin lacking the entire lactone subunit demonstrated marked potency and selectivity for PP2A, while having substantially reduced and similar activity against PP1 and PP1/PP2A- PP5/PP2A-chimeras that have greatly increased sensitivity to both fostriecin and cytostatin. This suggests that other features [e.g., the (Z,Z,E)-triene] also contribute to inhibitory selectivity. When considered together with previous data, these studies suggest that, despite the high structural conservation of the catalytic site in PP1, PP2A and PP5, the development of highly selective catalytic inhibitors should be feasible.
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Affiliation(s)
- Mark R Swingle
- Department of Biochemistry and Molecular Biology, University of South Alabama College of Medicine, Mobile, USA
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21
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McConnell JL, Wadzinski BE. Targeting protein serine/threonine phosphatases for drug development. Mol Pharmacol 2009; 75:1249-61. [PMID: 19299564 DOI: 10.1124/mol.108.053140] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
With the recent clinical success of drugs targeting protein kinase activity, drug discovery efforts are focusing on the role of reversible protein phosphorylation in disease states. The activity of protein phosphatases, enzymes that oppose protein kinases, can also be manipulated to alter cellular signaling for therapeutic benefits. In this review, we present protein serine/threonine phosphatases as viable therapeutic targets, discussing past successes, current challenges, and future strategies for modulating phosphatase activity.
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Affiliation(s)
- Jamie L McConnell
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-6600, USA
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22
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Olano C, Méndez C, Salas JA. Antitumor compounds from actinomycetes: from gene clusters to new derivatives by combinatorial biosynthesis. Nat Prod Rep 2009; 26:628-60. [PMID: 19387499 DOI: 10.1039/b822528a] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Covering: up to October 2008. Antitumor compounds produced by actinomycetes and novel derivatives generated by combinatorial biosynthesis are reviewed (with 318 references cited.) The different structural groups for which the relevant gene clusters have been isolated and characterized are reviewed, with a description of the strategies used for the generation of the novel derivatives and the activities of these compounds against tumor cell lines.
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Affiliation(s)
- Carlos Olano
- Departamento de Biología Funcional and Instituto Universitario de Oncología del Principado de Asturias (I.U.O.P.A.), Universidad de Oviedo, 33006, Oviedo, Spain
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23
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Druais V, Hall MJ, Corsi C, Wendeborn SV, Meyer C, Cossy J. A Convergent Approach toward the C1−C11 Subunit of Phoslactomycins and Formal Synthesis of Phoslactomycin B. Org Lett 2009; 11:935-8. [DOI: 10.1021/ol8029142] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Valérie Druais
- Laboratoire de Chimie Organique, ESPCI ParisTech, CNRS, 10 rue Vauquelin, 75231 Paris Cedex 05, France, and Syngenta Crop Protection Muenchwilen AG, WST-820.2.15, Schaffhauserestrasse, 4332 Stein, Switzerland
| | - Michael J. Hall
- Laboratoire de Chimie Organique, ESPCI ParisTech, CNRS, 10 rue Vauquelin, 75231 Paris Cedex 05, France, and Syngenta Crop Protection Muenchwilen AG, WST-820.2.15, Schaffhauserestrasse, 4332 Stein, Switzerland
| | - Camilla Corsi
- Laboratoire de Chimie Organique, ESPCI ParisTech, CNRS, 10 rue Vauquelin, 75231 Paris Cedex 05, France, and Syngenta Crop Protection Muenchwilen AG, WST-820.2.15, Schaffhauserestrasse, 4332 Stein, Switzerland
| | - Sebastian V. Wendeborn
- Laboratoire de Chimie Organique, ESPCI ParisTech, CNRS, 10 rue Vauquelin, 75231 Paris Cedex 05, France, and Syngenta Crop Protection Muenchwilen AG, WST-820.2.15, Schaffhauserestrasse, 4332 Stein, Switzerland
| | - Christophe Meyer
- Laboratoire de Chimie Organique, ESPCI ParisTech, CNRS, 10 rue Vauquelin, 75231 Paris Cedex 05, France, and Syngenta Crop Protection Muenchwilen AG, WST-820.2.15, Schaffhauserestrasse, 4332 Stein, Switzerland
| | - Janine Cossy
- Laboratoire de Chimie Organique, ESPCI ParisTech, CNRS, 10 rue Vauquelin, 75231 Paris Cedex 05, France, and Syngenta Crop Protection Muenchwilen AG, WST-820.2.15, Schaffhauserestrasse, 4332 Stein, Switzerland
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Salit AF, Meyer C, Cossy J, Delouvrié B, Hennequin L. Synthetic studies toward cytostatin, a natural product inhibitor of protein phosphatase 2A. Tetrahedron 2008. [DOI: 10.1016/j.tet.2008.05.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Miyashita K, Tsunemi T, Hosokawa T, Ikejiri M, Imanishi T. Total Synthesis of Leustroducsin B. J Org Chem 2008; 73:5360-70. [DOI: 10.1021/jo8005599] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kazuyuki Miyashita
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan, and Faculty of Pharmacy, Osaka Ohtani University, 3-11-1 Nishikiori-kita, Tondabayashi, Osaka 584-8540, Japan
| | - Tomoyuki Tsunemi
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan, and Faculty of Pharmacy, Osaka Ohtani University, 3-11-1 Nishikiori-kita, Tondabayashi, Osaka 584-8540, Japan
| | - Takafumi Hosokawa
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan, and Faculty of Pharmacy, Osaka Ohtani University, 3-11-1 Nishikiori-kita, Tondabayashi, Osaka 584-8540, Japan
| | - Masahiro Ikejiri
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan, and Faculty of Pharmacy, Osaka Ohtani University, 3-11-1 Nishikiori-kita, Tondabayashi, Osaka 584-8540, Japan
| | - Takeshi Imanishi
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan, and Faculty of Pharmacy, Osaka Ohtani University, 3-11-1 Nishikiori-kita, Tondabayashi, Osaka 584-8540, Japan
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26
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Shibahara S, Fujino M, Tashiro Y, Takahashi K, Ishihara J, Hatakeyama S. Asymmetric Total Synthesis of (+)-Phoslactomycin B. Org Lett 2008; 10:2139-42. [DOI: 10.1021/ol8004672] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Setsuya Shibahara
- Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521, Japan
| | - Masataka Fujino
- Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521, Japan
| | - Yasumasa Tashiro
- Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521, Japan
| | - Keisuke Takahashi
- Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521, Japan
| | - Jun Ishihara
- Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521, Japan
| | - Susumi Hatakeyama
- Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521, Japan
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27
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Trotta R, Ciarlariello D, Dal Col J, Allard J, Neviani P, Santhanam R, Mao H, Becknell B, Yu J, Ferketich AK, Thomas B, Modi A, Blaser BW, Perrotti D, Caligiuri MA. The PP2A inhibitor SET regulates natural killer cell IFN-gamma production. ACTA ACUST UNITED AC 2007; 204:2397-405. [PMID: 17875674 PMCID: PMC2118465 DOI: 10.1084/jem.20070419] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Monokines (i.e., interleukin [IL]-12, -18, and -15) induce natural killer (NK) cells to produce interferon-γ (IFN-γ), which is a critical factor for immune surveillance of cancer and monocyte clearance of infection. We show that SET, which is a potent inhibitor of protein phosphatase type 2A (PP2A) activity, is highly expressed in human CD56bright NK cells, which produce more IFN-γ than CD56dim NK cells. SET was up-regulated upon monokine stimulation of primary human NK cells. Furthermore, ectopic overexpression of SET significantly enhanced IFN-γ gene expression in monokine-stimulated NK cells. In contrast, RNAi-mediated suppression of SET expression renders NK cells inefficient in producing high levels of IFN-γ in response to monokine costimulation. Mechanistically, suppression of PP2A activity by SET is important for IFN-γ gene expression in NK cells. In fact, treatment of primary human NK cells with the PP2A activator 1,9-dideoxy-forskolin, as well as administration of the drug to C57BL/6 mice, significantly reduced NK-dependent IFN-γ production in response to monokine treatment. Further, SET knockdown or pharmacologic activation of PP2A diminished extracellular signal-regulated kinase 1/2, p65RelA, signal transducer and activator of transduction 4 (STAT4), and STAT5 activity in monokine-stimulated NK cells, potentially contributing to the reduction in IFN-γ gene expression. Thus, SET expression is essential for suppressing PP2A phosphatase activity that would otherwise limit NK cell antitumoral and/or antiinflammatory functions by impairing NK cell production of IFN-γ.
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Affiliation(s)
- Rossana Trotta
- Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University, Columbus, OH 43210, USA.
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28
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Miyashita K, Tsunemi T, Hosokawa T, Ikejiri M, Imanishi T. Total synthesis of leustroducsin B via a convergent route. Tetrahedron Lett 2007. [DOI: 10.1016/j.tetlet.2007.03.152] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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29
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Lawhorn BG, Boga SB, Wolkenberg SE, Colby DA, Gauss CM, Swingle MR, Amable L, Honkanen RE, Boger DL. Total synthesis and evaluation of cytostatin, its C10-C11 diastereomers, and additional key analogues: impact on PP2A inhibition. J Am Chem Soc 2006; 128:16720-32. [PMID: 17177422 PMCID: PMC2566737 DOI: 10.1021/ja066477d] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The total synthesis of cytostatin, an antitumor agent belonging to the fostriecin family of natural products, is described in full detail. The convergent approach relied on a key epoxide-opening reaction to join the two stereotriad units and a single-step late-stage stereoselective installation of the sensitive (Z,Z,E)-triene through a beta-chelation-controlled nucleophilic addition. The synthetic route provided rapid access to the C4-C6 stereoisomers of the cytostatin lactone, which were prepared and used to define the C4-C6 relative stereochemistry of the natural product. In addition to the natural product, each of the C10-C11 diastereomers of cytostatin was divergently prepared (11 steps from key convergence step) by this route and used to unequivocally confirm the relative and absolute stereochemistry of cytostatin. Each of the cytostatin diastereomers exhibited a reduced activity toward inhibition of PP2A (>100-fold), demonstrating the importance of the presence and stereochemistry of the C10-methyl and C11-hydroxy groups for potent PP2A inhibition. Extensions of the studies provided dephosphocytostatin, sulfocytostatin (a key analogue related to the natural product sultriecin), 11-deshydroxycytostatin, and an analogue lacking the entire C12-C18 (Z,Z,E)-triene segment, which were used to define the magnitude of the C9-phosphate (>4000-fold), C11-alcohol (250-fold), and triene (220-fold) contribution to PP2A inhibition. A model of cytostatin bound to the active site of PP2A is presented, compared to that of fostriecin, which is also presented in detail for the first time, and used to provide insights into the role of the key substituents. Notably, the alpha,beta unsaturated lactone of cytostatin, like that of fostriecin, is projected to serve as a key electrophile, providing a covalent adduct with Cys269 unique to PP2A, contributing to its potency (> or =200-fold for fostriecin) and accounting for its selectivity.
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Affiliation(s)
- Brian G. Lawhorn
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037
| | - Sobhana B. Boga
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037
| | - Scott E. Wolkenberg
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037
| | - David A. Colby
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037
| | - Carla-Maria Gauss
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037
| | - Mark R. Swingle
- Department of Biochemistry and Molecular Biology, University of South Alabama College of Medicine, Mobile, Alabama 36688
| | - Lauren Amable
- Department of Biochemistry and Molecular Biology, University of South Alabama College of Medicine, Mobile, Alabama 36688
| | - Richard E. Honkanen
- Department of Biochemistry and Molecular Biology, University of South Alabama College of Medicine, Mobile, Alabama 36688
| | - Dale L. Boger
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037
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Ghatge M, Palaniappan N, Das Choudhuri S, Reynolds K. Genetic manipulation of the biosynthetic process leading to phoslactomycins, potent protein phosphatase 2A inhibitors. J Ind Microbiol Biotechnol 2006; 33:589-99. [PMID: 16609856 DOI: 10.1007/s10295-006-0116-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Accepted: 03/16/2006] [Indexed: 11/27/2022]
Abstract
Phoslactomycins (PLMs) represent an unusual structural class of natural products secreted by various streptomycetes, containing an alpha,beta-unsaturated delta-lactone, an amino group, phosphate ester, conjugated diene and a cyclohexane ring. Phosphazomycins, phospholines and leustroducsins contain the same structural moieties, varying only in the acyl substituent at the C-18 hydroxyl position. These compounds possess either antifungal or antitumor activities or both. The antitumor activity of the PLM class of compounds has been attributed to a potent and selective inhibition of protein phosphatase 2A (PP2A). The cysteine-269 residue of PP2Ac-subunit has been shown to be the site of covalent modification by PLMs. In this article, we review previous work on the isolation, structure elucidation and biological activities of PLMs and related compounds and current status of our work on both PLM stability and genetic manipulation of the biosynthetic process. Our work has shown that PLM B is surprisingly stable in solution, with a pH optimum of 6. Preliminary biosynthetic studies utilizing isotopically labeled shikimic acid and cyclohexanecarboxylic acid (CHC) suggested PLM B to be a polyketide-type antibiotic synthesized using CHC as a starter unit. Using a gene (chcA) from a set of CHC-CoA biosynthesis genes from Streptomyces collinus as a probe, a 75 kb region of 29 ORFs encoding PLM biosynthesis was located in the genome of Streptomyces sp. strain HK803. Analysis and subsequent manipulation of plmS2 and plmR2 in the gene cluster has allowed for rational engineering of a strain that produces only one PLM analog, PLM B, at ninefold higher titers than the wild type strain. A strain producing PLM G (the penultimate intermediate in PLMs biosynthesis) has also been generated. Current work is aimed at selective in vitro acylation of PLM G with various carboxylic acids and a precursor-directed biosynthesis in a chcA deletion mutant with the aim of generating novel PLM analogs.
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Affiliation(s)
- Mohini Ghatge
- Department of Chemistry, Portland State University, P.O. Box 751, Portland, OR 97207-0751, USA
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31
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Masuda T, Ohba S, Kawada M, Iijima M, Inoue H, Osono M, Ikeda D, Kunimoto S. Augmentation of Cellular Immunity by Kigamicin D. J Antibiot (Tokyo) 2006; 59:215-9. [PMID: 16830888 DOI: 10.1038/ja.2006.30] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Kigamicin D did not show any immunosuppressive activity in mixed lymphocyte culture reaction and mitogen induced lymphocyte blastogenesis in vitro and graft versus host reaction in vivo. Natural killer cell activity in spleen cells was not affected by oral administration of kigamicin D. Instead, delayed-type hypersensitivity response to sheep red blood cells was stimulated at a broad dosage level. It is concluded that kigamicin D increases cellular immunity to specific antigen.
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Affiliation(s)
- Toru Masuda
- Numazu Bio-Medical Research Institute, Microbial Chemistry Research Center, 18-24 Miyamoto, Numazu-shi, Shizuoka 410-0301, Japan.
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Teruya T, Simizu S, Kanoh N, Osada H. Phoslactomycin targets cysteine-269 of the protein phosphatase 2A catalytic subunit in cells. FEBS Lett 2005; 579:2463-8. [PMID: 15848189 DOI: 10.1016/j.febslet.2005.03.049] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2005] [Revised: 03/06/2005] [Accepted: 03/16/2005] [Indexed: 01/17/2023]
Abstract
According to the chemical genetic approach, small molecules that bind directly to proteins are used to analyze protein function, thereby enabling the elucidation of complex mechanisms in mammal cells. Thus, it is very important to identify the molecular targets of compounds that induce a unique phenotype in a target cell. Phoslactomycin A (PLMA) is known to be a potent inhibitor of protein Ser/Thr phosphatase 2A (PP2A); however, the inhibitory mechanism of PP2A by PLMA has not yet been elucidated. Here, we demonstrated that PLMA directly binds to the PP2A catalytic subunit (PP2Ac) in cells by using biotinylated PLMA, and the PLMA-binding site was identified as the Cys-269 residue of PP2Ac. Moreover, we revealed that the Cys-269 contributes to the potent inhibition of PP2Ac activity by PLMA. These results suggest that PLMA is a PP2A-selective inhibitor and is therefore expected to be useful for future investigation of PP2A function in cells.
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Affiliation(s)
- Takayuki Teruya
- Antibiotics Laboratory, Discovery Research Institute, RIKEN, Wako, Saitama, Japan
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Torres A, Hochberg M, Pergament I, Smoum R, Niddam V, Dembitsky VM, Temina M, Dor I, Lev O, Srebnik M, Enk CD. A new UV-B absorbing mycosporine with photo protective activity from the lichenized ascomycete Collema cristatum. ACTA ACUST UNITED AC 2004; 271:780-4. [PMID: 14764094 DOI: 10.1111/j.1432-1033.2004.03981.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A novel photo protective mycosporine was isolated from the lichenized ascomycete Collema cristatum. Biological activity was measured in terms of protection against UV-B induced membrane destruction and pyrimidine dimer formation in cultured human keratinocytes, and prevention of UV-B induced erythema. It was found that the pure isolated compound prevented UV-B induced cell destruction in a dose-dependent manner, that the compound partially prevented pyrimidine dimer formation and completely prevented UV-B induced erythema when applied to the skin prior to irradiation.
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Affiliation(s)
- Avital Torres
- Department of Medicinal Chemistry and Natural Products, School of Pharmacy, Hebrew University of Jerusalem, Israel
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35
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Palaniappan N, Kim BS, Sekiyama Y, Osada H, Reynolds KA. Enhancement and selective production of phoslactomycin B, a protein phosphatase IIa inhibitor, through identification and engineering of the corresponding biosynthetic gene cluster. J Biol Chem 2003; 278:35552-7. [PMID: 12819191 DOI: 10.1074/jbc.m305082200] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phoslactomycins (PLMs), potent and selective inhibitors of serine threonine phosphatases, are of interest for their antitumor and antiviral activity. Multiple analogs and low titers in the fermentation process have hampered the development of this class of natural products. The entire 75-kb PLM biosynthetic gene cluster of Streptomyces sp. HK-803 was cloned, sequenced, and analyzed. The loading domain and seven extension modules of the PLM polyketide synthase generate an unusual linear unsaturated polyketide chain containing both E- and Z-double bonds from a cyclohexanecarboxylic acid (CHC) primer. Hydroxylation of the CHC-derived side chain of the resulting PLM-B by PlmS2, and a subsequent esterification, produces the remaining PLM analogs. A new PCR targeting technology allowed rapid and facile allelic replacement of plmS2. The resulting mutant selectively produced the PLM-B, at 6-fold higher titers than the wild type strain. This mutant and the biosynthetic gene cluster will facilitate engineered microbial production of hybrid PLMs with improved properties.
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Affiliation(s)
- Nadaraj Palaniappan
- Department of Medicinal Chemistry and Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia 23219, USA
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36
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Sekiyama Y, Palaniappan N, Reynolds KA, Osada H. Biosynthesis of phoslactomycins: cyclohexanecarboxylic acid as the starter unit. Tetrahedron 2003. [DOI: 10.1016/s0040-4020(03)01205-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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