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Mubarak SJ, Gupta S, Vedagiri H. Scaffold Hopping and Screening for Potent Small Molecule Agonists for GRP94: Implications to Alleviate ER Stress-Associated Pathogenesis. Mol Biotechnol 2024; 66:737-755. [PMID: 36763304 DOI: 10.1007/s12033-023-00685-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 01/27/2023] [Indexed: 02/11/2023]
Abstract
Disparity in the activity of Endoplasmic reticulum (ER) leads to degenerative diseases, mainly associated with protein misfolding and aggregation leading to cellular dysfunction and damage, ultimately contributing to ER stress. ER stress activates the complex network of Unfolded Protein Response (UPR) signaling pathways mediated by transmembrane proteins IRE1, ATF6, and PERK. In addition to UPR, many ER chaperones have evolved to optimize the output of properly folded secretory and membrane proteins. Glucose-regulated protein 94 (GRP94), an ER chaperone of heat shock protein HSP90 family, directs protein folding through interaction with other components of the ER protein folding machinery and assists in ER-associated degradation (ERAD). Activation of GRP94 would increase the efficacy of protein folding machinery and regulate the UPR pathway toward homeostasis. The present study aims to screen for novel agonists for GRP94 based on Core hopping, pharmacophore hypothesis, 3D-QSAR, and virtual screening with small-molecule compound libraries in order to improve the efficiency of native protein folding by enhancing GRP94 chaperone activity, therefore to reduce protein misfolding and aggregation. In this study, we have employed the strategy of small molecule-dependent ER programming to enhance the chaperone activity of GRP94 through scaffold hopping-based screening approach to identify specific GRP94 agonists. New scaffolds generated by altering the cores of NECA, the known GRP94 agonist, were validated by employing pharmacophore hypothesis testing, 3D-QSAR modeling, and molecular dynamics simulations. This facilitated the identification of small molecules to improve the efficiency of native protein folding by enhancing GRP94 activity. High-throughput virtual screening of the selected pharmacophore hypothesis against Selleckchem and ZINC databases retrieved a total of 2,27,081 compounds. Further analysis on docking and ADMET properties revealed Epimedin A, Narcissoside, Eriocitrin 1,2,3,4,6-O-Pentagalloylglucose, Secoisolariciresinol diglucoside, ZINC92952357, ZINC67650204, and ZINC72457930 as potential lead molecules. The stability and interaction of these small molecules were far better than the known agonist, NECA indicating their efficacy in selectively alleviating ER stress-associated pathogenesis. These results substantiate the fact that small molecule-dependent ER reprogramming would activate the ER chaperones and therefore reduce the protein misfolding as well as aggregation associated with ER stress in order to restore cellular homeostasis.
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Affiliation(s)
| | - Surabhi Gupta
- Department of Reproductive Biology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Hemamalini Vedagiri
- Department of Bioinformatics, Bharathiar University, Coimbatore, Tamil Nadu, India.
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Significance of Targeting VEGFR-2 and Cyclin D1 in Luminal-A Breast Cancer. Molecules 2020; 25:molecules25204606. [PMID: 33050377 PMCID: PMC7594023 DOI: 10.3390/molecules25204606] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 09/29/2020] [Accepted: 10/06/2020] [Indexed: 12/24/2022] Open
Abstract
The hormonal luminal-A is the most pre-dominant sub type of breast cancer (BC), and it is associated with a high level of cyclin D1 in Saudi patients. Tamoxifen is the golden therapy for hormonal BC, but resistance of cancer cells to tamoxifen contributes to the recurrence of BC due to many reasons, including high levels of AIB1 and cyclin D1. Overcoming drug resistance could be achieved by exploring alternative targetable therapeutic pathways and new drugs or combinations. The objective of this study was to determine the differentially enriched pathways in 12 samples of Saudi women diagnosed with luminal-A using the PamChip peptide microarray-based kinase activity profiling, and to compare the activity of HAA2020 and dinaciclib with tamoxifen in singles and combinations in the MCF7 luminal-A cell line. Our results of network and pathway analysis of the 12 samples highlighted the importance of VEGFR and CDKs in promoting luminal-A breast cancer. The activation of VEGF signaling via VEGFR-2 leads to activation of PI3K/AKT kinases and an increase of cell survival, and leads to activation of Hsp90, which induces the phosphorylation of FAK1, resulting in cytoskeleton remodeling. PLC-gamma 1 is also activated, leading to FAK-2 and PKC activation. Notably, the G1/S cell cycle phases and phosphorylation processes contribute to the top seven tumorigenesis processes in the 12 samples. Further, the MTT combination of HAA2020 and dinaciclib showed the best combination index (CI), was more clonogenic against MCF7 cells compared to the other combinations, and it also showed the best selectivity index (SI) in normal MRC5 cells. Interestingly, HAA2020 and dinaciclib showed a synergistic apoptotic and G1 cell cycle effect in MCF7 cells, which was supported by their synergistic CDK2, cyclin D1, and PCNA inhibition activities. Additionally, the combination showed VEGFR-2 and Hsp90 inhibition activities in MCF7 cells. The results show the significance of targeting VEGFR-2 and cyclin D1 in Saudi luminal-A breast cancer patients, and the effect of combining HAA2020 and dinaciclib on those targets in the MCF7 model. It also warrants further preclinical and in vivo investigations for the combination of HAA2020 and dinaciclib as a possible future second-line treatment for luminal-A breast cancers.
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Stimulation of the ATPase activity of Hsp90 by zerumbone modification of its cysteine residues destabilizes its clients and causes cytotoxicity. Biochem J 2018; 475:2559-2576. [DOI: 10.1042/bcj20180230] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 07/13/2018] [Accepted: 07/16/2018] [Indexed: 12/14/2022]
Abstract
Hsp90 is an ATP-dependent molecular chaperone that assists folding and conformational maturation/maintenance of many proteins. It is a potential cancer drug target because it chaperones oncoproteins. A prokaryotic homolog of Hsp90 (HtpG) is essential for thermo-tolerance in some bacteria and virulence of zoonotic pathogens. To identify a new class of small molecules which target prokaryotic and eukaryotic Hsp90s, we studied the effects of a naturally occurring cyclic sesquiterpene, zerumbone, which inhibits proliferation of a wide variety of tumor cells, on the activity of Hsp90. Zerumbone enhanced the ATPase activity of cyanobacterial Hsp90 (Hsp90SE), yeast Hsp90, and human Hsp90α. It also enhanced the catalytic efficiency of Hsp90SE by greatly increasing kcat. Mass analysis showed that zerumbone binds to cysteine side chains of Hsp90SE covalently. Mutational studies identified 3 cysteine residues (one per each domain of Hsp90SE) that are involved in the enhancement, suggesting the presence of allosteric sites in the middle and C-terminal domains of Hsp90SE. Treatment of cyanobacterial cells with zerumbone caused them to become very temperature-sensitive, a phenotype reminiscent of cyanobacterial Hsp90 mutants, and also decreased the cellular level of linker polypeptides that are clients for Hsp90SE. Zerumbone showed cellular toxicity on cancer-derived mammalian cells by inducing apoptosis. In addition, zerumbone inhibited the binding of Hsp90/Cdc37 to client kinases. Altogether, we conclude that modification of cysteine residues of Hsp90 by zerumbone enhances its ATPase activity and inhibits physiological Hsp90 function. The activation of Hsp90 may provide new strategies to inhibit its chaperone function in cells.
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Jain P, Sethi SC, Pratyusha VA, Garai P, Naqvi N, Singh S, Pawar K, Puri N, Komath SS. Ras signaling activates glycosylphosphatidylinositol (GPI) anchor biosynthesis via the GPI- N-acetylglucosaminyltransferase (GPI-GnT) in Candida albicans. J Biol Chem 2018; 293:12222-12238. [PMID: 29907567 DOI: 10.1074/jbc.ra117.001225] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 04/17/2018] [Indexed: 01/08/2023] Open
Abstract
The ability of Candida albicans to switch between yeast to hyphal form is a property that is primarily associated with the invasion and virulence of this human pathogenic fungus. Several glycosylphosphatidylinositol (GPI)-anchored proteins are expressed only during hyphal morphogenesis. One of the major pathways that controls hyphal morphogenesis is the Ras-signaling pathway. We examine the cross-talk between GPI anchor biosynthesis and Ras signaling in C. albicans. We show that the first step of GPI biosynthesis is activated by Ras in C. albicans This is diametrically opposite to what is reported in Saccharomyces cerevisiae Of the two C. albicans Ras proteins, CaRas1 alone activates GPI-GnT activity; activity is further stimulated by constitutively activated CaRas1. CaRas1 localized to the cytoplasm or endoplasmic reticulum (ER) is sufficient for GPI-GnT activation. Of the six subunits of the GPI-N-acetylglucosaminyltransferase (GPI-GnT) that catalyze the first step of GPI biosynthesis, CaGpi2 is the key player involved in activating Ras signaling and hyphal morphogenesis. Activation of Ras signaling is independent of the catalytic competence of GPI-GnT. This too is unlike what is observed in S. cerevisiae where multiple subunits were identified as inhibiting Ras2. Fluorescence resonance energy transfer (FRET) studies indicate a specific physical interaction between CaRas1 and CaGpi2 in the ER, which would explain the ability of CaRas1 to activate GPI-GnT. CaGpi2, in turn, promotes activation of the Ras-signaling pathway and hyphal morphogenesis. The Cagpi2 mutant is also more susceptible to macrophage-mediated killing, and macrophage cells show better survival when co-cultured with Cagpi2.
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Affiliation(s)
- Priyanka Jain
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India
| | | | | | - Pramita Garai
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India
| | - Nilofer Naqvi
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India
| | - Sonali Singh
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India
| | - Kalpana Pawar
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India
| | - Niti Puri
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India
| | - Sneha Sudha Komath
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India.
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5
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Ras hyperactivation versus overexpression: Lessons from Ras dynamics in Candida albicans. Sci Rep 2018; 8:5248. [PMID: 29588468 PMCID: PMC5869725 DOI: 10.1038/s41598-018-23187-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 03/06/2018] [Indexed: 12/25/2022] Open
Abstract
Ras signaling in response to environmental cues is critical for cellular morphogenesis in eukaryotes. This signaling is tightly regulated and its activation involves multiple players. Sometimes Ras signaling may be hyperactivated. In C. albicans, a human pathogenic fungus, we demonstrate that dynamics of hyperactivated Ras1 (Ras1G13V or Ras1 in Hsp90 deficient strains) can be reliably differentiated from that of normal Ras1 at (near) single molecule level using fluorescence correlation spectroscopy (FCS). Ras1 hyperactivation results in significantly slower dynamics due to actin polymerization. Activating actin polymerization by jasplakinolide can produce hyperactivated Ras1 dynamics. In a sterol-deficient hyperfilamentous GPI mutant of C. albicans too, Ras1 hyperactivation results from Hsp90 downregulation and causes actin polymerization. Hyperactivated Ras1 co-localizes with G-actin at the plasma membrane rather than with F-actin. Depolymerizing actin with cytochalasin D results in faster Ras1 dynamics in these and other strains that show Ras1 hyperactivation. Further, ergosterol does not influence Ras1 dynamics.
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Lei W, Mullen N, McCarthy S, Brann C, Richard P, Cormier J, Edwards K, Bilsky EJ, Streicher JM. Heat-shock protein 90 (Hsp90) promotes opioid-induced anti-nociception by an ERK mitogen-activated protein kinase (MAPK) mechanism in mouse brain. J Biol Chem 2017; 292:10414-10428. [PMID: 28450396 DOI: 10.1074/jbc.m116.769489] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 04/13/2017] [Indexed: 12/26/2022] Open
Abstract
Recent advances in developing opioid treatments for pain with reduced side effects have focused on the signaling cascades of the μ-opioid receptor (MOR). However, few such signaling targets have been identified for exploitation. To address this need, we explored the role of heat-shock protein 90 (Hsp90) in opioid-induced MOR signaling and pain, which has only been studied in four previous articles. First, in four cell models of MOR signaling, we found that Hsp90 inhibition for 24 h with the inhibitor 17-N-allylamino-17-demethoxygeldanamycin (17-AAG) had different effects on protein expression and opioid signaling in each line, suggesting that cell models may not be reliable for predicting pharmacology with this protein. We thus developed an in vivo model using CD-1 mice with an intracerebroventricular injection of 17-AAG for 24 h. We found that Hsp90 inhibition strongly blocked morphine-induced anti-nociception in models of post-surgical and HIV neuropathic pain but only slightly blocked anti-nociception in a naive tail-flick model, while enhancing morphine-induced precipitated withdrawal. Seeking a mechanism for these changes, we found that Hsp90 inhibition blocks ERK MAPK activation in the periaqueductal gray and caudal brain stem. We tested these signaling changes by inhibiting ERK in the above-mentioned pain models and found that ERK inhibition could account for all of the changes in anti-nociception induced by Hsp90 inhibition. Taken together, these findings suggest that Hsp90 promotes opioid-induced anti-nociception by an ERK mechanism in mouse brain and that Hsp90 could be a future target for improving the therapeutic index of opioid drugs.
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Affiliation(s)
- Wei Lei
- From the Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona 85724
| | - Nathan Mullen
- the Department of Biomedical Sciences, College of Osteopathic Medicine, University of New England, Biddeford, Maine 04005, and
| | - Sarah McCarthy
- the Department of Biomedical Sciences, College of Osteopathic Medicine, University of New England, Biddeford, Maine 04005, and
| | - Courtney Brann
- the Department of Biomedical Sciences, College of Osteopathic Medicine, University of New England, Biddeford, Maine 04005, and
| | - Philomena Richard
- the Department of Biomedical Sciences, College of Osteopathic Medicine, University of New England, Biddeford, Maine 04005, and
| | - James Cormier
- the Department of Biomedical Sciences, College of Osteopathic Medicine, University of New England, Biddeford, Maine 04005, and
| | - Katie Edwards
- the Department of Biomedical Sciences, College of Osteopathic Medicine, University of New England, Biddeford, Maine 04005, and
| | - Edward J Bilsky
- the Department of Biomedical Sciences, College of Osteopathic Medicine, University of New England, Biddeford, Maine 04005, and.,the Department of Biomedical Sciences, College of Osteopathic Medicine, Pacific Northwest University, Yakima, Washington 98901
| | - John M Streicher
- From the Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona 85724,
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Olson KM, Lei W, Keresztes A, LaVigne J, Streicher JM. Novel Molecular Strategies and Targets for Opioid Drug Discovery for the Treatment of Chronic Pain. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2017; 90:97-110. [PMID: 28356897 PMCID: PMC5369049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Opioid drugs like morphine and fentanyl are the gold standard for treating moderate to severe acute and chronic pain. However, opioid drug use can be limited by serious side effects, including constipation, tolerance, respiratory suppression, and addiction. For more than 100 years, we have tried to develop opioids that decrease or eliminate these liabilities, with little success. Recent advances in understanding opioid receptor signal transduction have suggested new possibilities to activate the opioid receptors to cause analgesia, while reducing or eliminating unwanted side effects. These new approaches include designing functionally selective ligands, which activate desired signaling cascades while avoiding signaling cascades that are thought to provoke side effects. It may also be possible to directly modulate downstream signaling through the use of selective activators and inhibitors. Separate from downstream signal transduction, it has also been found that when the opioid system is stimulated, various negative feedback systems are upregulated to compensate, which can drive side effects. This has led to the development of multi-functional molecules that simultaneously activate the opioid receptor while blocking various negative feedback receptor systems including cholecystokinin and neurokinin-1. Other novel approaches include targeting heterodimers of the opioid and other receptor systems which may drive side effects, and making endogenous opioid peptides druggable, which may also reduce opioid mediated side effects. Taken together, these advances in our molecular understanding provide a path forward to break the barrier in producing an opioid with reduced or eliminated side effects, especially addiction, which may provide relief for millions of patients.
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Affiliation(s)
- Keith M. Olson
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ,Department of Chemistry and Biochemistry, College of Science, University of Arizona, Tucson, AZ
| | - Wei Lei
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ
| | - Attila Keresztes
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ
| | - Justin LaVigne
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ
| | - John M. Streicher
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ,To whom all correspondence should be addressed: John M. Streicher, Ph.D., University of Arizona, College of Medicine, Department of Pharmacology, Life Sciences North 563, Box 245050, 1501 N. Campbell Ave., Tucson, AZ 85724, 520-626-7495,
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Egeland NG, Lunde S, Jonsdottir K, Lende TH, Cronin-Fenton D, Gilje B, Janssen EAM, Søiland H. The Role of MicroRNAs as Predictors of Response to Tamoxifen Treatment in Breast Cancer Patients. Int J Mol Sci 2015; 16:24243-75. [PMID: 26473850 PMCID: PMC4632748 DOI: 10.3390/ijms161024243] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 09/28/2015] [Accepted: 09/30/2015] [Indexed: 12/13/2022] Open
Abstract
Endocrine therapy is a key treatment strategy to control or eradicate hormone-responsive breast cancer. However, resistance to endocrine therapy leads to breast cancer relapse. The recent extension of adjuvant tamoxifen treatment up to 10 years actualizes the need for identifying biological markers that may be used to monitor predictors of treatment response. MicroRNAs are promising biomarkers that may fill the gap between preclinical knowledge and clinical observations regarding endocrine resistance. MicroRNAs regulate gene expression by posttranscriptional repression or degradation of mRNA, most often leading to gene silencing. MicroRNAs have been identified directly in the primary tumor, but also in the circulation of breast cancer patients. The few available studies investigating microRNA in patients suggest that seven microRNAs (miR-10a, miR-26, miR-30c, miR-126a, miR-210, miR-342 and miR-519a) play a role in tamoxifen resistance. Ingenuity Pathway Analysis (IPA) reveals that these seven microRNAs interact more readily with estrogen receptor (ER)-independent pathways than ER-related signaling pathways. Some of these pathways are targetable (e.g., PIK3CA), suggesting that microRNAs as biomarkers of endocrine resistance may have clinical value. Validation of the role of these candidate microRNAs in large prospective studies is warranted.
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Affiliation(s)
- Nina G Egeland
- Department of Pathology, Stavanger University Hospital, Gerd Ragna Bloch Thorsens Gate 8, 4011 Stavanger, Norway.
- Department of Mathematics and Natural Sciences, University of Stavanger, 4036 Stavanger, Norway.
| | - Siri Lunde
- Department of Breast and Endocrine Surgery, Stavanger University Hospital, 4011 Stavanger, Norway.
| | - Kristin Jonsdottir
- Department of Pathology, Stavanger University Hospital, Gerd Ragna Bloch Thorsens Gate 8, 4011 Stavanger, Norway.
| | - Tone H Lende
- Department of Breast and Endocrine Surgery, Stavanger University Hospital, 4011 Stavanger, Norway.
- Department of Clinical Science, University of Bergen, Postboks 7804, 5020 Bergen, Norway.
| | - Deirdre Cronin-Fenton
- Department of Clinical Epidemiology, Aarhus University, Science Center Skejby, Olof Palmes Allé 43, Aarhus N, 8200 Aarhus, Denmark.
| | - Bjørnar Gilje
- Department of Haematology and Oncology, Stavanger University Hospital, Gerd Ragna Bloch Thorsens Gate 8, 4011 Stavanger, Norway.
| | - Emiel A M Janssen
- Department of Pathology, Stavanger University Hospital, Gerd Ragna Bloch Thorsens Gate 8, 4011 Stavanger, Norway.
- Department of Mathematics and Natural Sciences, University of Stavanger, 4036 Stavanger, Norway.
| | - Håvard Søiland
- Department of Breast and Endocrine Surgery, Stavanger University Hospital, 4011 Stavanger, Norway.
- Department of Clinical Science, University of Bergen, Postboks 7804, 5020 Bergen, Norway.
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Zierer BK, Weiwad M, Rübbelke M, Freiburger L, Fischer G, Lorenz OR, Sattler M, Richter K, Buchner J. Aktivatoren des molekularen Chaperons Hsp90 erleichtern geschwindigkeitsbestimmende Konformationsänderungen. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201406578] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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10
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Yokoyama Y, Ohtaki A, Jantan I, Yohda M, Nakamoto H. Goniothalamin enhances the ATPase activity of the molecular chaperone Hsp90 but inhibits its chaperone activity. J Biochem 2014; 157:161-8. [PMID: 25294885 DOI: 10.1093/jb/mvu061] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Hsp90 is an ATP-dependent molecular chaperone that is involved in important cellular pathways such as signal transduction pathways. It is a potential cancer drug target because it plays a critical role for stabilization and activation of oncoproteins. Thus, small molecule compounds that control the Hsp90 function are useful to elucidate potential lead compounds against cancer. We studied effect of a naturally occurring styryl-lactone goniothalamin on the activity of Hsp90. Although many drugs targeting Hsp90 inhibit the ATPase activity of Hsp90, goniothalamin enhanced rather than inhibited the ATPase activity of a cyanobacterial Hsp90 (HtpG) and a yeast Hsp90. It increased both K(m) and k(cat) of the Hsp90s. Domain competition assays and tryptophan fluorescence measurements with various truncated derivatives of HtpG indicated that goniothalamin binds to the N-terminal domain of HtpG. Goniothalamin did not influence on the interaction of HtpG with a non-native protein or the anti-aggregation activity of HtpG significantly. However, it inhibited the activity of HtpG that assists refolding of a non-native protein in cooperation with the Hsp70 chaperone system. This is the first report to show that a small molecule that binds to the N-terminal domain of Hsp90 activates its ATPase activity, while inhibiting the chaperone function of Hsp90.
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Affiliation(s)
- Yuhei Yokoyama
- Molecular Biology Course, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan; Faculty of Pharmacy, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Malaysia; and Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Aguru Ohtaki
- Molecular Biology Course, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan; Faculty of Pharmacy, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Malaysia; and Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Ibrahim Jantan
- Molecular Biology Course, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan; Faculty of Pharmacy, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Malaysia; and Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Masafumi Yohda
- Molecular Biology Course, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan; Faculty of Pharmacy, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Malaysia; and Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Hitoshi Nakamoto
- Molecular Biology Course, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan; Faculty of Pharmacy, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Malaysia; and Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
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11
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Zierer BK, Weiwad M, Rübbelke M, Freiburger L, Fischer G, Lorenz OR, Sattler M, Richter K, Buchner J. Artificial accelerators of the molecular chaperone Hsp90 facilitate rate-limiting conformational transitions. Angew Chem Int Ed Engl 2014; 53:12257-62. [PMID: 25244159 DOI: 10.1002/anie.201406578] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Indexed: 11/09/2022]
Abstract
The molecular chaperone Hsp90 undergoes an ATP-driven cycle of conformational changes in which large structural rearrangements precede ATP hydrolysis. Well-established small-molecule inhibitors of Hsp90 compete with ATP-binding. We wondered whether compounds exist that can accelerate the conformational cycle. In a FRET-based screen reporting on conformational rearrangements in Hsp90 we identified compounds. We elucidated their mode of action and showed that they can overcome the intrinsic inhibition in Hsp90 which prevents these rearrangements. The mode of action is similar to that of the co-chaperone Aha1 which accelerates the Hsp90 ATPase. However, while the two identified compounds influence conformational changes, they target different aspects of the structural transitions. Also, the binding site determined by NMR spectroscopy is distinct. This study demonstrates that small molecules are capable of triggering specific rate-limiting transitions in Hsp90 by mechanisms similar to those in protein cofactors.
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Affiliation(s)
- Bettina K Zierer
- Center for Integrated Protein Science Munich (CIPSM) Department Chemie, Technische Universität München, 85747 Garching (Germany)
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12
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Tamoxifen induces apoptosis through cancerous inhibitor of protein phosphatase 2A-dependent phospho-Akt inactivation in estrogen receptor-negative human breast cancer cells. Breast Cancer Res 2014; 16:431. [PMID: 25228280 PMCID: PMC4303112 DOI: 10.1186/s13058-014-0431-9] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 08/21/2014] [Indexed: 11/11/2022] Open
Abstract
Introduction Tamoxifen, a selective estrogen receptor (ER) modulator, may affect cancer cell survival through mechanisms other than ER antagonism. In the present study, we tested the efficacy of tamoxifen in a panel of ER-negative breast cancer cell lines and examined the drug mechanism. Methods In total, five ER-negative breast cancer cell lines (HCC-1937, MDA-MB-231, MDA-MB-468, MDA-MB-453 and SK-BR-3) were used for in vitro studies. Cellular apoptosis was examined by flow cytometry and Western blot analysis. Signal transduction pathways in cells were assessed by Western blot analysis. The in vivo efficacy of tamoxifen was tested in xenograft nude mice. Results Tamoxifen induced significant apoptosis in MDA-MB-231, MDA-MB-468, MDA-MB-453 and SK-BR-3 cells, but not in HCC-1937 cells. Tamoxifen-induced apoptosis was associated with inhibition of cancerous inhibitor of protein phosphatase 2A (CIP2A) and phospho-Akt (p-Akt) in a dose-dependent manner. Ectopic expression of either CIP2A or Akt protected MDA-MB-231 cells from tamoxifen-induced apoptosis. In addition, tamoxifen increased protein phosphatase 2A (PP2A) activity, and tamoxifen-induced apoptosis was attenuated by the PP2A antagonist okadaic acid in the sensitive cell lines, but not in resistant HCC-1937 cells. Moreover, silencing CIP2A by small interfering RNA sensitized HCC-1937 cells to tamoxifen-induced apoptosis. Furthermore, tamoxifen regulated CIP2A protein expression by downregulating CIP2A mRNA. Importantly, tamoxifen inhibited the in vivo growth of MDA-MB-468 xenograft tumors in association with CIP2A downregulation, whereas tamoxifen had no significant effect on CIP2A expression and anti-tumor growth in HCC-1937 tumors. Conclusions Inhibition of CIP2A determines the effects of tamoxifen-induced apoptosis in ER-negative breast cancer cells. Our data suggest a novel “off-target“ mechanism of tamoxifen and suggest that CIP2A/PP2A/p-Akt signaling may be a feasible anti-cancer pathway. Electronic supplementary material The online version of this article (doi:10.1186/s13058-014-0431-9) contains supplementary material, which is available to authorized users.
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Shahinas D, Folefoc A, Taldone T, Chiosis G, Crandall I, Pillai DR. A purine analog synergizes with chloroquine (CQ) by targeting Plasmodium falciparum Hsp90 (PfHsp90). PLoS One 2013; 8:e75446. [PMID: 24098696 PMCID: PMC3787104 DOI: 10.1371/journal.pone.0075446] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 08/18/2013] [Indexed: 12/31/2022] Open
Abstract
Background Drug resistance, absence of an effective vaccine, and inadequate public health measures are major impediments to controlling Plasmodium falciparum malaria worldwide. The development of antimalarials to which resistance is less likely is paramount. To this end, we have exploited the chaperone function of P. falciparum Hsp90 (PfHsp90) that serves to facilitate the expression of resistance determinants. Methods The affinity and activity of a purine analogue Hsp90 inhibitor (PU-H71) on PfHsp90 was determined using surface plasmon resonance (SPR) studies and an ATPase activity assay, respectively. In vitro, antimalarial activity was quantified using flow cytometry. Interactors of PfHsp90 were determined by LC-MS/MS. In vivo studies were conducted using the Plasmodium berghei infection mouse model. Results PU-H71 exhibited antimalarial activity in the nanomolar range, displayed synergistic activity with chloroquine in vitro. Affinity studies reveal that the PfHsp90 interacts either directly or indirectly with the P. falciparum chloroquine resistance transporter (PfCRT) responsible for chloroquine resistance. PU-H71 synergized with chloroquine in the P.berghei mouse model of malaria to reduce parasitemia and improve survival. Conclusions We propose that the interaction of PfHsp90 with PfCRT may account for the observed antimalarial synergy and that PU-H71 is an effective adjunct for combination therapy.
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Affiliation(s)
- Dea Shahinas
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Asongna Folefoc
- Department of Pathology & Laboratory Medicine and Medicine, The University of Calgary, Calgary, Alberta, Canada
| | - Tony Taldone
- Memorial Sloan-Kettering Cancer Center New York, New York, United States of America
| | - Gabriela Chiosis
- Memorial Sloan-Kettering Cancer Center New York, New York, United States of America
| | - Ian Crandall
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Dylan R. Pillai
- Department of Pathology & Laboratory Medicine and Medicine, The University of Calgary, Calgary, Alberta, Canada
- Department of Microbiology, Immunology, and Infectious Diseases, The University of Calgary, Calgary, Alberta, Canada
- * E-mail:
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Cruz IN, Zhang Y, de la Fuente M, Schatzlein A, Yang M. Functional characterization of heat shock protein 90 targeted compounds. Anal Biochem 2013; 438:107-9. [DOI: 10.1016/j.ab.2013.03.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2013] [Revised: 03/21/2013] [Accepted: 03/22/2013] [Indexed: 01/16/2023]
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Eckert K, Saliou JM, Monlezun L, Vigouroux A, Atmane N, Caillat C, Quevillon-Chéruel S, Madiona K, Nicaise M, Lazereg S, Van Dorsselaer A, Sanglier-Cianférani S, Meyer P, Moréra S. The Pih1-Tah1 cochaperone complex inhibits Hsp90 molecular chaperone ATPase activity. J Biol Chem 2010; 285:31304-12. [PMID: 20663878 DOI: 10.1074/jbc.m110.138263] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Hsp90 (heat shock protein 90) is an ATP-dependent molecular chaperone regulated by collaborating proteins called cochaperones. This machinery is involved in the conformational activation of client proteins like signaling kinases, transcription factors, or ribonucleoproteins (RNP) such as telomerase. TPR (TetratricoPeptide Repeat)-containing protein associated with Hsp90 (Tah1) and protein interacting with Hsp90 (Pih1) have been identified in Saccharomyces cerevisiae as two Hsp90 cochaperones involved in chromatin remodeling complexes and small nucleolar RNP maturation. Tah1 possesses a minimal TPR domain and binds specifically to the Hsp90 C terminus, whereas Pih1 displays no homology to other protein motifs and has been involved in core RNP protein interaction. While Pih1 alone was unstable and was degraded from its N terminus, we showed that Pih1 and Tah1 form a stable heterodimeric complex that regulates Hsp90 ATPase activity. We used different biophysical approaches such as analytical ultracentrifugation, microcalorimetry, and noncovalent mass spectrometry to characterize the Pih1-Tah1 complex and its interaction with Hsp90. We showed that the Pih1-Tah1 heterodimer binds to Hsp90 with a similar affinity and the same stoichiometry as Tah1 alone. However, the Pih1-Tah1 complex antagonizes Tah1 activity on Hsp90 and inhibits the chaperone ATPase activity. We further identified the region within Pih1 responsible for interaction with Tah1 and inhibition of Hsp90, allowing us to suggest an interaction model for the Pih1-Tah1/Hsp90 complex. These results, together with previous reports, suggest a role for the Pih1-Tah1 cochaperone complex in the recruitment of client proteins such as core RNP proteins to Hsp90.
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Affiliation(s)
- Kelvin Eckert
- Laboratoire d'Enzymologie et Biochimie Structurales, CNRS, 91198 Gif-sur-Yvette, France
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