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Kumawat R, Tomar RS. Dissecting the role of mitogen-activated protein kinase Hog1 in yeast flocculation. FEBS J 2024. [PMID: 38648231 DOI: 10.1111/febs.17137] [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: 09/20/2023] [Revised: 01/25/2024] [Accepted: 04/05/2024] [Indexed: 04/25/2024]
Abstract
Living organisms are frequently exposed to multiple biotic and abiotic stress forms during their lifetime. Organisms cope with stress conditions by regulating their gene expression programs. In response to different environmental stress conditions, yeast cells activate different tolerance mechanisms, many of which share common signaling pathways. Flocculation is one of the key mechanisms underlying yeast survival under unfavorable environmental conditions, and the Tup1-Cyc8 corepressor complex is a major regulator of this process. Additionally, yeast cells can utilize different mitogen-activated protein kinase (MAPK) pathways to modulate gene expression during stress conditions. Here, we show that the high osmolarity glycerol (HOG) MAPK pathway is involved in the regulation of yeast flocculation. We observed that the HOG MAPK pathway was constitutively activated in flocculating cells, and found that the interaction between phosphorylated Hog1 and the FLO genes promoter region increased significantly upon sodium chloride exposure. We found that treatment of cells with cantharidin decreased Hog1 phosphorylation, causing a sharp reduction in the expression of FLO genes and the flocculation phenotype. Similarly, deletion of HOG1 in yeast cells reduced flocculation. Altogether, our results suggest a role for HOG MAPK signaling in the regulation of FLO genes and yeast flocculation.
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Affiliation(s)
- Ramesh Kumawat
- Stowers Institute for Medical Research, Kansas City, MO, USA
| | - Raghuvir Singh Tomar
- Laboratory of Chromatin Biology, Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, India
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2
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Pradhan RN, Shrestha B, Lee Y. Avoiding cantharidin through ionotropic receptors. JOURNAL OF HAZARDOUS MATERIALS 2024; 466:133497. [PMID: 38278077 DOI: 10.1016/j.jhazmat.2024.133497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 01/08/2024] [Accepted: 01/09/2024] [Indexed: 01/28/2024]
Abstract
The discernment and aversion of noxious gustatory stimuli profoundly influence homeostasis maintenance and survival of fauna. Cantharidin, a purported aphrodisiac, is a monoterpenoid compound secreted by many species of blister beetle, particularly by the Spanish fly, Lytta vesicatoria. Although the various advantageous functions of cantharidin have been described, its taste analysis and toxic properties in animalshave been rarely explored. Our study using Drosophila melanogaster examines the taste properties of cantharidin along with its potential hazardous effect in the internal organs of animals. Here, we find that cantharidin activates bitter taste receptors. Our findings show that specific ionotropic receptors (IR7g, IR51b, and IR94f) in labellar bitter-sensing neurons, along with co-receptors IR25a and IR76b, are responsible for detecting cantharidin. By introducing the IR7g and IR51b in sweet and bitter neurons, naturally expressing IR76b and IR25a, we show that these genes are sufficient for cantharidin perception. Moreover, we witness the deleterious ramifications of cantharidin on survival and visceral integrities, shedding light on its hazardous effect.
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Affiliation(s)
- Roshani Nhuchhen Pradhan
- Department of Bio & Fermentation Convergence Technology, Kookmin University, Seoul 02707, Republic of Korea
| | - Bhanu Shrestha
- Department of Bio & Fermentation Convergence Technology, Kookmin University, Seoul 02707, Republic of Korea
| | - Youngseok Lee
- Department of Bio & Fermentation Convergence Technology, Kookmin University, Seoul 02707, Republic of Korea.
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3
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Li D. Structure and Function of the Glycosylphosphatidylinositol Transamidase, a Transmembrane Complex Catalyzing GPI Anchoring of Proteins. Subcell Biochem 2024; 104:425-458. [PMID: 38963495 DOI: 10.1007/978-3-031-58843-3_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
Glycosylphosphatidylinositol (GPI) anchoring of proteins is a ubiquitous posttranslational modification in eukaryotic cells. GPI-anchored proteins (GPI-APs) play critical roles in enzymatic, signaling, regulatory, and adhesion processes. Over 20 enzymes are involved in GPI synthesis, attachment to client proteins, and remodeling after attachment. The GPI transamidase (GPI-T), a large complex located in the endoplasmic reticulum membrane, catalyzes the attachment step by replacing a C-terminal signal peptide of proproteins with GPI. In the last three decades, extensive research has been conducted on the mechanism of the transamidation reaction, the components of the GPI-T complex, the role of each subunit, and the substrate specificity. Two recent studies have reported the three-dimensional architecture of GPI-T, which represent the first structures of the pathway. The structures provide detailed mechanisms for assembly that rationalizes previous biochemical results and subunit-dependent stability data. While the structural data confirm the catalytic role of PIGK, which likely uses a caspase-like mechanism to cleave the proproteins, they suggest that unlike previously proposed, GPAA1 is not a catalytic subunit. The structures also reveal a shared cavity for GPI binding. Somewhat unexpectedly, PIGT, a single-pass membrane protein, plays a crucial role in GPI recognition. Consistent with the assembly mechanisms and the active site architecture, most of the disease mutations occur near the active site or the subunit interfaces. Finally, the catalytic dyad is located ~22 Å away from the membrane interface of the GPI-binding site, and this architecture may confer substrate specificity through topological matching between the substrates and the elongated active site. The research conducted thus far sheds light on the intricate processes involved in GPI anchoring and paves the way for further mechanistic studies of GPI-T.
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Affiliation(s)
- Dianfan Li
- CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences (CAS), Shanghai, China.
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4
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Tutanov OS, Glass SE, Coffey RJ. Emerging connections between GPI-anchored proteins and their extracellular carriers in colorectal cancer. EXTRACELLULAR VESICLES AND CIRCULATING NUCLEIC ACIDS 2023; 4:195-217. [PMID: 37840781 PMCID: PMC10569057 DOI: 10.20517/evcna.2023.17] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
Although extracellular vesicles (EVs) were discovered over 40 years ago, there has been a resurgence of interest in secreted vesicles and their attendant cargo as novel modes of intracellular communication. In addition to vesicles, two amembranous nanoparticles, exomeres and supermeres, have been isolated and characterized recently. In this rapidly expanding field, it has been challenging to assign cargo and specific functions to a particular carrier. Refinement of isolation methods, well-controlled studies, and guidelines detailed by Minimal Information for Studies of Extracellular Vesicles (MISEV) are being employed to "bring order to chaos." In this review, we will briefly summarize three types of extracellular carriers - small EVs (sEVs), exomeres, and supermeres - in the context of colorectal cancer (CRC). We found that a number of GPI-anchored proteins (GPI-APs) are overexpressed in CRC, are enriched in exosomes (a distinct subset of sEVs), and can be detected in exomeres and supermeres. This affords the opportunity to elaborate on GPI-AP biogenesis, modifications, and trafficking using DPEP1, a GPI-AP upregulated in CRC, as a prime example. We have cataloged the GPI-anchored proteins secreted in CRC and will highlight features of select CRC-associated GPI-anchored proteins we have detected. Finally, we will discuss the remaining challenges and future opportunities in studying these secreted GPI-APs in CRC.
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Affiliation(s)
- Oleg S. Tutanov
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
| | - Sarah E. Glass
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee 37232, USA
| | - Robert J. Coffey
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
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5
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Kundu S, Lin C, Jaiswal M, Mullapudi VB, Craig KC, Chen S, Guo Z. Profiling Glycosylphosphatidylinositol (GPI)-Interacting Proteins in the Cell Membrane Using a Bifunctional GPI Analogue as the Probe. J Proteome Res 2023; 22:919-930. [PMID: 36700487 PMCID: PMC9992086 DOI: 10.1021/acs.jproteome.2c00728] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Glycosylphosphatidylinositol (GPI) anchorage of cell surface proteins to the membrane is biologically important and ubiquitous in eukaryotes. However, GPIs do not contain long enough lipids to span the entire membrane bilayer. To transduce binding signals, GPIs must interact with other membrane components, but such interactions are difficult to define. Here, a new method was developed to explore GPI-interacting membrane proteins in live cell with a bifunctional analogue of the glucosaminylphosphatidylinositol motif conserved in all GPIs as a probe. This probe contained a diazirine functionality in the lipid and an alkynyl group on the glucosamine residue to respectively facilitate the cross-linkage of GPI-binding membrane proteins with the probe upon photoactivation and then the installation of biotin to the cross-linked proteins via a click reaction for affinity-based protein isolation and analysis. Profiling the proteins pulled down from the Hela cells revealed 94 unique and 18 overrepresented proteins compared to the control, and most of them are membrane proteins and many are GPI-related. The results have proved not only the concept of using the new bifunctional GPI probe to investigate GPI-binding membrane proteins but also the important role of inositol in the biological functions of GPI anchors and GPI-anchored proteins.
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Affiliation(s)
- Sayan Kundu
- Department of Chemistry, University of Florida, Gainesville, Florida32611, United States
| | - Chuwei Lin
- Department of Biology, Genetics Institute, University of Florida, Gainesville, Florida32611, United States
| | - Mohit Jaiswal
- Department of Chemistry, University of Florida, Gainesville, Florida32611, United States
| | | | - Kendall C Craig
- Department of Chemistry, University of Florida, Gainesville, Florida32611, United States
| | - Sixue Chen
- Department of Biology, Genetics Institute, University of Florida, Gainesville, Florida32611, United States
| | - Zhongwu Guo
- Department of Chemistry, University of Florida, Gainesville, Florida32611, United States
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Wang Q, Song W, Tian Y, Hu P, Liu X, Xu L, Gong Z. Targeted Lipidomics Reveal the Effect of Perchlorate on Lipid Profiles in Liver of High-Fat Diet Mice. Front Nutr 2022; 9:837601. [PMID: 35360694 PMCID: PMC8964020 DOI: 10.3389/fnut.2022.837601] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 02/08/2022] [Indexed: 01/05/2023] Open
Abstract
Perchlorate, commonly available in drinking water and food, acts on the iodine uptake by the thyroid affecting lipid metabolism. High-fat diets leading to various health problems continually raise public concern. In the present study, liver lipid metabolism profiles and metabolic pathways were investigated in C57BL/6J mice chronically exposed to perchlorate using targeted metabolomics. Mice were fed a high-fat diet and treated orally with perchlorate at 0.1 mg/kg bw (body weight), 1 mg/kg bw and 10 mg/kg bw daily for 12 weeks. Perchlorate induced disorders of lipid metabolism in vivo and hepatic lipid accumulation confirmed by serum biochemical parameters and histopathological examination. There were 34 kinds of lipid in liver detected by UHPLC-MS/MS and key metabolites were identified by multivariate statistical analysis evaluated with VIP > 1, p-value < 0.05, fold change > 1.2 or < 0.8. Perchlorate low, medium and high dose groups were identified with 11, 7 and 8 significantly altered lipid metabolites compared to the control group, respectively. The results of the metabolic pathway analysis revealed that the differential metabolites classified into different experimental groups contribute to the glycerophospholipid metabolic pathway. These findings provide insights into the effects of perchlorate on lipid metabolism during long-term exposure to high-fat diets and contribute to the evaluation of perchlorate liver toxic mechanisms and health effects.
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Affiliation(s)
- Qiao Wang
- Key Laboratory for Deep Processing of Major Grain and Oil (The Chinese Ministry of Education), College of Food Science and Engineering, Wuhan Polytechnic University, Wuhan, China
| | - Wanying Song
- Key Laboratory for Deep Processing of Major Grain and Oil (The Chinese Ministry of Education), College of Food Science and Engineering, Wuhan Polytechnic University, Wuhan, China
| | - Yimei Tian
- Key Laboratory for Deep Processing of Major Grain and Oil (The Chinese Ministry of Education), College of Food Science and Engineering, Wuhan Polytechnic University, Wuhan, China
| | - Peihao Hu
- Key Laboratory for Deep Processing of Major Grain and Oil (The Chinese Ministry of Education), College of Food Science and Engineering, Wuhan Polytechnic University, Wuhan, China
| | - Xin Liu
- Key Laboratory for Deep Processing of Major Grain and Oil (The Chinese Ministry of Education), College of Food Science and Engineering, Wuhan Polytechnic University, Wuhan, China
| | - Lin Xu
- Key Laboratory for Deep Processing of Major Grain and Oil (The Chinese Ministry of Education), College of Food Science and Engineering, Wuhan Polytechnic University, Wuhan, China
| | - Zhiyong Gong
- Key Laboratory for Deep Processing of Major Grain and Oil (The Chinese Ministry of Education), College of Food Science and Engineering, Wuhan Polytechnic University, Wuhan, China
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Swagatika S, Tomar RS. Cantharidin downregulates PSD1 expression and inhibits autophagic flux in yeast cells. FEBS Open Bio 2021; 12:1017-1035. [PMID: 33999504 PMCID: PMC9063437 DOI: 10.1002/2211-5463.13196] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 04/07/2021] [Accepted: 05/14/2021] [Indexed: 11/10/2022] Open
Abstract
Cantharidin is a terpenoid compound of insect origin, naturally produced by male blister beetles as an anti-predatory mechanism. Cantharidin has anticancer properties, which are attributed to its ability to induce cell cycle arrest, DNA damage, MAPK signalling pathway and apoptosis. Cantharidin has been reported to induce apoptosis in triple-negative breast cancer cells by suppressing autophagy via downregulation of Beclin 1 expression and autophagosome formation. However, it remains unclear which stage of the autophagic pathway is targeted by cantharidin. Herein, we report that yeast cells are sensitive to cantharidin, and external supplementation of ethanolamine (ETA) ameliorates the cytotoxicity. In addition, cantharidin downregulates phosphatidylserine decarboxylase1 (PSD1) expression. We also report that cantharidin inhibits autophagic flux, and external administration of ETA could rescue this inhibition. Additionally, co-treatment with chloroquine sensitized the autophagy inhibitory effects of cantharidin. We conclude that yeast cells are sensitive to cantharidin due to inhibition of autophagic flux.
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Affiliation(s)
- Swati Swagatika
- Laboratory of Chromatin Biology, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal-462066, MP, India
| | - Raghuvir Singh Tomar
- Laboratory of Chromatin Biology, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal-462066, MP, India
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8
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Swagatika S, Tomar RS. ABC transporter Pdr5 is required for cantharidin resistance in Saccharomyces cerevisiae. Biochem Biophys Res Commun 2021; 553:141-147. [PMID: 33770579 DOI: 10.1016/j.bbrc.2021.03.074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 03/15/2021] [Indexed: 01/22/2023]
Abstract
Cantharidin is a potent anti-cancer drug and is known to exert its cytotoxic effects in several cancer cell lines. Although we have ample knowledge about its mode of action, we still know a little about cantharidin associated drug resistance mechanisms which dictates the efficacy and cytotoxic potential of this drug. In this direction, in the present study we employed Sacharomyces cerevisiae as a model organism and screened mutants of pleiotropic drug resistance network of genes for their susceptibility to cantharidin. We show that growth of pdr1Δ and pdr1Δpdr3Δ was severely reduced in presence of cantharidin whereas that of pdr3Δ remain unaffected when compared to wildtype. Loss of one of the PDR1 target genes PDR5, encoding an ABC membrane efflux pump, rendered the cells hypersensitive whereas overexpression of it conferred resistance. Additionally, cantharidin induced the upregulation of both PDR1 and PDR5 genes. Interestingly, pdr1Δpdr5Δ double deletion mutants were hypersensitive to cantharidin showing a synergistic effect in its cellular detoxification. Furthermore, transcriptional activation of PDR5 post cantharidin treatment was majorly dependent on the presence of Pdr1 and less significantly of Pdr3 transcription factors. Altogether our findings suggest that Pdr1 acts to increase cantharidin resistance by elevating the level of Pdr5 which serves as a major detoxification safeguard under CAN stress.
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Affiliation(s)
- Swati Swagatika
- Laboratory of Chromatin Biology, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, 462066, MP, India
| | - Raghuvir Singh Tomar
- Laboratory of Chromatin Biology, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, 462066, MP, India.
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9
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Woydziak ZR, Yucel AJ, Chamberlin AR. Tautomycetin Synthetic Analogues: Selective Inhibitors of Protein Phosphatase I. ChemMedChem 2021; 16:839-850. [PMID: 33301228 PMCID: PMC8582298 DOI: 10.1002/cmdc.202000801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Indexed: 01/21/2023]
Abstract
Ser/Thr protein phosphatases (PPs) regulate a substantial range of cellular processes with protein phosphatases 1 (PP1) and 2 A (PP2A) accounting for over 90 % of the activity within cells. Nevertheless, tools to study PPs are limited as PPs inhibitors, particularly those selective for PP1 inhibition, are relatively scarce. Two examples of PP1-selective inhibitors, which share structural similarities, are tautomycin (TTM) and tautomycetin (TTN). This work describes the development of PP1/PP2A inhibitors that incorporate key structural features of TTM and TTN and are designed to conserve regions known to bind the active site of PP1/PP2A but vary regions that differentially contact the hydrophobic groove of PP1/PP2A. In all 28 TTN analogues were synthetically generated that inhibit PP1/PP2A activity at <250 mM; seven possessed inhibition activity at 100 nM. The IC50 values were determined for the seven most active analogues, which ranged from 34 to 1500 nM (PP1) and 70 to 6800 nM (PP2A). Four of the seven analogues possessed PP1 selectivity, and one demonstrated eightfold selectivity in the nanomolar range (PP1 IC50 =34 nM, PP2A IC50 =270 nM). A rationale is given for the observed differences in selectivity.
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Affiliation(s)
- Zachary R Woydziak
- Department of Physical and Life Sciences, Nevada State College, 1300, Nevada State Dr., Henderson, NV 89002, USA
| | - A John Yucel
- Department of Pharmaceutical Sciences, University of California, Irvine, 147 Biol. Sci. Admin., Irvine, CA 92697, USA
| | - A Richard Chamberlin
- Department of Pharmaceutical Sciences, University of California, Irvine, 147 Biol. Sci. Admin., Irvine, CA 92697, USA
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Potential Physiological Relevance of ERAD to the Biosynthesis of GPI-Anchored Proteins in Yeast. Int J Mol Sci 2021; 22:ijms22031061. [PMID: 33494405 PMCID: PMC7865462 DOI: 10.3390/ijms22031061] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/18/2021] [Accepted: 01/19/2021] [Indexed: 12/19/2022] Open
Abstract
Misfolded and/or unassembled secretory and membrane proteins in the endoplasmic reticulum (ER) may be retro-translocated into the cytoplasm, where they undergo ER-associated degradation, or ERAD. The mechanisms by which misfolded proteins are recognized and degraded through this pathway have been studied extensively; however, our understanding of the physiological role of ERAD remains limited. This review describes the biosynthesis and quality control of glycosylphosphatidylinositol (GPI)-anchored proteins and briefly summarizes the relevance of ERAD to these processes. While recent studies suggest that ERAD functions as a fail-safe mechanism for the degradation of misfolded GPI-anchored proteins, several pieces of evidence suggest an intimate interaction between ERAD and the biosynthesis of GPI-anchored proteins.
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Antitumor potential of the protein phosphatase inhibitor, cantharidin, and selected derivatives. Bioorg Med Chem 2021; 32:116012. [PMID: 33454654 DOI: 10.1016/j.bmc.2021.116012] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 12/31/2020] [Accepted: 01/04/2021] [Indexed: 12/21/2022]
Abstract
Cantharidin is a potent natural protein phosphatase monoterpene anhydride inhibitor secreted by several species of blister beetle, with its demethylated anhydride analogue, (S)-palasonin, occurring as a constituent of the higher plant Butea frondosa. Cantharidin shows both potent protein phosphatase inhibitory and cancer cell cytotoxic activities, but possible preclinical development of this anhydride has been limited thus far by its toxicity. Thus, several synthetic derivatives of cantharidin have been prepared, of which some compounds exhibit improved antitumor potential and may have use as lead compounds. In the present review, the potential antitumor activity, structure-activity relationships, and development of cantharidin-based anticancer drug conjugates are summarized, with protein phosphatase-related and other types of mechanisms of action discussed. Protein phosphatases play a key role in the tumor microenvironment, and thus described herein is also the potential for developing new tumor microenvironment-targeted cancer chemotherapeutic agents, based on cantharidin and its naturally occurring analogues and synthetic derivatives.
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12
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Structural base for the transfer of GPI-anchored glycoproteins into fungal cell walls. Proc Natl Acad Sci U S A 2020; 117:22061-22067. [PMID: 32839341 DOI: 10.1073/pnas.2010661117] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The correct distribution and trafficking of proteins are essential for all organisms. Eukaryotes evolved a sophisticated trafficking system which allows proteins to reach their destination within highly compartmentalized cells. One eukaryotic hallmark is the attachment of a glycosylphosphatidylinositol (GPI) anchor to C-terminal ω-peptides, which are used as a zip code to guide a subset of membrane-anchored proteins through the secretory pathway to the plasma membrane. In fungi, the final destination of many GPI-anchored proteins is their outermost compartment, the cell wall. Enzymes of the Dfg5 subfamily catalyze the essential transfer of GPI-anchored substrates from the plasma membrane to the cell wall and discriminate between plasma membrane-resident GPI-anchored proteins and those transferred to the cell wall (GPI-CWP). We solved the structure of Dfg5 from a filamentous fungus and used in crystallo glycan fragment screening to reassemble the GPI-core glycan in a U-shaped conformation within its binding pocket. The resulting model of the membrane-bound Dfg5•GPI-CWP complex is validated by molecular dynamics (MD) simulations and in vivo mutants in yeast. The latter show that impaired transfer of GPI-CWPs causes distorted cell-wall integrity as indicated by increased chitin levels. The structure of a Dfg5•β1,3-glycoside complex predicts transfer of GPI-CWP toward the nonreducing ends of acceptor glycans in the cell wall. In addition to our molecular model for Dfg5-mediated transglycosylation, we provide a rationale for how GPI-CWPs are specifically sorted toward the cell wall by using GPI-core glycan modifications.
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Naz F, Wu Y, Zhang N, Yang Z, Yu C. Anticancer Attributes of Cantharidin: Involved Molecular Mechanisms and Pathways. Molecules 2020; 25:E3279. [PMID: 32707651 PMCID: PMC7397086 DOI: 10.3390/molecules25143279] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/15/2020] [Accepted: 07/16/2020] [Indexed: 12/12/2022] Open
Abstract
Cancer is a preeminent threat to the human race, causing millions of deaths each year on the Earth. Traditionally, natural compounds are deemed promising agents for cancer treatment. Cantharidin (CTD)-a terpenoid isolated from blister beetles-has been used extensively in traditional Chinese medicines for healing various maladies and cancer. CTD has been proven to be protein phosphatase 2A (PP2A) and heat shock transcription factor 1 (HSF-1) inhibitor, which can be potential targets for its anticancer activity. Albeit, it harbors some toxicities, its immense anticancer potential cannot be overlooked, as the cancer-specific delivery of CTD could help to rescue its lethal effects. Furthermore, several derivatives have been designed to weaken its toxicity. In light of extensive research, the antitumor activity of CTD is evident in both in vitro as well as in vivo cancer models. CTD has also proven efficacious in combination with chemotherapy and radiotherapy and it can also target some drug-resistant cancer cells. This mini-review endeavors to interpret and summarize recent information about CTD anticancer potential and underlying molecular mechanisms. The pertinent anticancer strength of CTD could be employed to develop an effective anticarcinogenic drug.
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Affiliation(s)
| | | | | | - Zhao Yang
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China; (F.N.); (Y.W.); (N.Z.)
| | - Changyuan Yu
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China; (F.N.); (Y.W.); (N.Z.)
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Kumar P, Swagatika S, Dasari S, Tomar RS, Patra AK. Modulation of ruthenium anticancer drugs analogs with tolfenamic acid: Reactivity, biological interactions and growth inhibition of yeast cell. J Inorg Biochem 2019; 199:110769. [DOI: 10.1016/j.jinorgbio.2019.110769] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 07/05/2019] [Accepted: 07/10/2019] [Indexed: 12/13/2022]
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15
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Ji XL, He M. Sodium cantharidate targets STAT3 and abrogates EGFR inhibitor resistance in osteosarcoma. Aging (Albany NY) 2019; 11:5848-5863. [PMID: 31422383 PMCID: PMC6710037 DOI: 10.18632/aging.102193] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 08/10/2019] [Indexed: 12/16/2022]
Abstract
Osteosarcoma is the most common primary malignant bone tumor in children and adolescents. Overactive EGFR signaling is frequently seen in osteosarcoma cells, and represents a potential therapeutic target. However, feedback activation of STAT3 after EGFR inhibition is linked to treatment resistance, suggesting that combined EGFR/STAT3 inhibition may be needed to overcome this effect. Cantharidin and its analogues have shown strong anticancer effects, including STAT3 inhibition, in several tumor cells. Therefore, we investigated the effects of sodium cantharidate (SC), either as monotherapy and in combination with the EGFR inhibitor erlotinib, on STAT3 activation and osteosarcoma cell growth. Cell viability, migration, and apoptosis assays were performed in human MG63 and U2OS cells, and MG63 xenografts were generated in nude mice to verify the suppression of tumor growth in vivo. Additionally, western blotting and immunohistochemistry were used to verify the STAT3 and EGFR phosphorylation statuses in xenografts. We found that SC repressed cell viability and migration and induced apoptosis in vitro, while combined SC and erlotinib treatment enhanced osteosarcoma growth suppression by preventing feedback activation of STAT3. These data support further development of cantharidin-based combination therapies for metastatic and recurrent/refractory osteosarcoma.
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Affiliation(s)
- Xiang Lu Ji
- Department of Orthopedic Surgery, Shengjing Hospital of China Medical University, Shenyang 110004, People's Republic of China
| | - Ming He
- Department of Orthopedic Surgery, Shengjing Hospital of China Medical University, Shenyang 110004, People's Republic of China
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16
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Sahu PK, Chauhan S, Tomar RS. The Crg1 N-Terminus Is Essential for Methyltransferase Activity and Cantharidin Resistance in Saccharomyces cerevisiae. Biochemistry 2019; 58:1799-1809. [PMID: 30830767 DOI: 10.1021/acs.biochem.8b01277] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Crg1 is an S-adenosylmethionine (SAM)-dependent methyltransferase required for cantharidin resistance in yeast. Crg1 has a well-characterized methyltransferase domain that inactivates cantharidin by methylation. However, the remaining part of the Crg1 protein is yet to be functionally characterized. In this study, we identified an essential role of the N-terminus of Crg1 in methyltransferase activity and cantharidin resistance. Yeast cells lacking 41 residues of the N-terminus of Crg1 ( crg1ΔN) showed hypersensitivity to cantharidin as same as the null mutant, crg1. The mass spectrometry-based biochemical enzyme assay revealed a loss of methyltransferase activity in Crg1ΔN, which justifies the loss of cantharidin resistance, as well. The subcellular distribution of Crg1ΔN-daGFP showed cytoplasmic aggregates, whereas wild-type Crg1-daGFP was distributed normally in the cytoplasm. Interestingly, the Crg1-methyltransferase domain point mutants (D44A, D67A, and E105A/D108A) also showed the same cytoplasmic aggregates as Crg1ΔN-daGFP. In silico prediction of the tertiary structures of these mutants indicated an altered protein conformation. Altogether, these observations suggest that the N-terminal truncation, as well as the point mutations in the methyltransferase domain, alters the native folding of Crg1 methyltransferase, resulting in a loss of enzyme activity. Furthermore, the crg1ΔN mutant showed the same phenotypes as the crg1 null mutant in the presence of cantharidin, i.e., lethal cell growth, PE auxotrophy, temperature sensitivity, endoplasmic reticulum stress, GPI anchor missorting, and cell wall damage. Overall, this study identifies an essential role of the N-terminus of Crg1 in methyltransferase activity and cantharidin resistance.
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Affiliation(s)
- Pushpendra Kumar Sahu
- Laboratory of Chromatin Biology, Department of Biological Sciences , Indian Institute of Science Education and Research Bhopal , Bhopal 462066 , Madhya Pradesh , India
| | - Sakshi Chauhan
- Laboratory of Chromatin Biology, Department of Biological Sciences , Indian Institute of Science Education and Research Bhopal , Bhopal 462066 , Madhya Pradesh , India
| | - Raghuvir Singh Tomar
- Laboratory of Chromatin Biology, Department of Biological Sciences , Indian Institute of Science Education and Research Bhopal , Bhopal 462066 , Madhya Pradesh , India
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