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Zhu Y, Zhao Y, Wen J, Liu S, Huang T, Hatial I, Peng X, Janabi HA, Huang G, Mittlesteadt J, Cheng M, Bhardwaj A, Ashfeld BL, Kao KR, Maeda DY, Dai X, Wiest O, Blagg BS, Lu X, Cheng L, Wan J, Lu X. Targeting the chromatin effector Pygo2 promotes cytotoxic T cell responses and overcomes immunotherapy resistance in prostate cancer. Sci Immunol 2023; 8:eade4656. [PMID: 36897957 PMCID: PMC10336890 DOI: 10.1126/sciimmunol.ade4656] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 02/16/2023] [Indexed: 03/12/2023]
Abstract
The noninflamed microenvironment in prostate cancer represents a barrier to immunotherapy. Genetic alterations underlying cancer cell-intrinsic oncogenic signaling are increasingly appreciated for their role in shaping the immune landscape. Recently, we identified Pygopus 2 (PYGO2) as the driver oncogene for the amplicon at 1q21.3 in prostate cancer. Here, using transgenic mouse models of metastatic prostate adenocarcinoma, we found that Pygo2 deletion decelerated tumor progression, diminished metastases, and extended survival. Pygo2 loss augmented the activation and infiltration of cytotoxic T lymphocytes (CTLs) and sensitized tumor cells to T cell killing. Mechanistically, Pygo2 orchestrated a p53/Sp1/Kit/Ido1 signaling network to foster a microenvironment hostile to CTLs. Genetic or pharmacological inhibition of Pygo2 enhanced the antitumor efficacy of immunotherapies using immune checkpoint blockade (ICB), adoptive cell transfer, or agents inhibiting myeloid-derived suppressor cells. In human prostate cancer samples, Pygo2 expression was inversely correlated with the infiltration of CD8+ T cells. Analysis of the ICB clinical data showed association between high PYGO2 level and worse outcome. Together, our results highlight a potential path to improve immunotherapy using Pygo2-targeted therapy for advanced prostate cancer.
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Affiliation(s)
- Yini Zhu
- Department of Biological Sciences, Boler-Parseghian Center for Rare and Neglected Diseases, Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556, USA
- Integrated Biomedical Sciences Graduate Program, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Yun Zhao
- Department of Biological Sciences, Boler-Parseghian Center for Rare and Neglected Diseases, Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Jiling Wen
- Department of Biological Sciences, Boler-Parseghian Center for Rare and Neglected Diseases, Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Sheng Liu
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Tianhe Huang
- Department of Biological Sciences, Boler-Parseghian Center for Rare and Neglected Diseases, Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Ishita Hatial
- Department of Chemistry and Biochemistry, Warren Family Research Center for Drug Discovery and Development, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Xiaoxia Peng
- Department of Biological Sciences, Boler-Parseghian Center for Rare and Neglected Diseases, Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Hawraa Al Janabi
- Department of Biological Sciences, Boler-Parseghian Center for Rare and Neglected Diseases, Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Gang Huang
- Department of Biological Sciences, Boler-Parseghian Center for Rare and Neglected Diseases, Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Jackson Mittlesteadt
- Department of Biological Sciences, Boler-Parseghian Center for Rare and Neglected Diseases, Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Michael Cheng
- Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Atul Bhardwaj
- Department of Chemistry and Biochemistry, Warren Family Research Center for Drug Discovery and Development, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Brandon L. Ashfeld
- Department of Chemistry and Biochemistry, Warren Family Research Center for Drug Discovery and Development, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Kenneth R. Kao
- Terry Fox Cancer Research Labs, Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John’s Campus, NL A1B 3V6, Canada
| | | | - Xing Dai
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, CA 92697, USA
| | - Olaf Wiest
- Department of Chemistry and Biochemistry, Warren Family Research Center for Drug Discovery and Development, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Brian S.J. Blagg
- Department of Chemistry and Biochemistry, Warren Family Research Center for Drug Discovery and Development, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Xuemin Lu
- Department of Biological Sciences, Boler-Parseghian Center for Rare and Neglected Diseases, Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Liang Cheng
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Pathology and Laboratory Medicine, Brown University Warren Alpert Medical School, Lifespan Academic Medical Center, and the Legorreta Cancer Center at Brown University, Providence, RI, USA
| | - Jun Wan
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- School of Informatics and Computing, Indiana University - Purdue University at Indianapolis, Indianapolis, IN 46202, USA
| | - Xin Lu
- Department of Biological Sciences, Boler-Parseghian Center for Rare and Neglected Diseases, Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556, USA
- Integrated Biomedical Sciences Graduate Program, University of Notre Dame, Notre Dame, IN 46556, USA
- Tumor Microenvironment and Metastasis Program, Indiana University Melvin and Bren Simon Comprehensive Cancer Center, Indianapolis, IN 46202, USA
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Nannapaneni DT, Chinthapally K, Hatial I, Ashfeld BL, Blagg BS. A succinct synthesis of (25R)-cholesta-5,7-diene-3β,26-diol from ergosterol. Tetrahedron Lett 2022. [DOI: 10.1016/j.tetlet.2022.153974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Serwetnyk MA, Blagg BS. The disruption of protein-protein interactions with co-chaperones and client substrates as a strategy towards Hsp90 inhibition. Acta Pharm Sin B 2021; 11:1446-1468. [PMID: 34221862 PMCID: PMC8245820 DOI: 10.1016/j.apsb.2020.11.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 10/12/2020] [Accepted: 11/13/2020] [Indexed: 12/16/2022] Open
Abstract
The 90-kiloDalton (kD) heat shock protein (Hsp90) is a ubiquitous, ATP-dependent molecular chaperone whose primary function is to ensure the proper folding of several hundred client protein substrates. Because many of these clients are overexpressed or become mutated during cancer progression, Hsp90 inhibition has been pursued as a potential strategy for cancer as one can target multiple oncoproteins and signaling pathways simultaneously. The first discovered Hsp90 inhibitors, geldanamycin and radicicol, function by competitively binding to Hsp90's N-terminal binding site and inhibiting its ATPase activity. However, most of these N-terminal inhibitors exhibited detrimental activities during clinical evaluation due to induction of the pro-survival heat shock response as well as poor selectivity amongst the four isoforms. Consequently, alternative approaches to Hsp90 inhibition have been pursued and include C-terminal inhibition, isoform-selective inhibition, and the disruption of Hsp90 protein-protein interactions. Since the Hsp90 protein folding cycle requires the assembly of Hsp90 into a large heteroprotein complex, along with various co-chaperones and immunophilins, the development of small molecules that prevent assembly of the complex offers an alternative method of Hsp90 inhibition.
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Key Words
- ADP, adenosine diphosphate
- ATP, adenosine triphosphate
- Aha1, activator of Hsp90 ATPase homologue 1
- CTD, C-terminal domain
- Cdc37, cell division cycle 37
- Disruptors
- Grp94, 94-kD glucose-regulated protein
- HIF-1α, hypoxia-inducing factor-1α
- HIP, Hsp70-interaction protein
- HOP, Hsp70‒Hsp90 organizing protein
- HSQC, heteronuclear single quantum coherence
- Her-2, human epidermal growth factor receptor-2
- Hsp90
- Hsp90, 90-kD heat shock protein
- MD, middle domain
- NTD, N-terminal domain
- Natural products
- PPI, protein−protein interaction
- Peptidomimetics
- Protein−protein interactions
- SAHA, suberoylanilide hydroxamic acid
- SAR, structure–activity relationship
- SUMO, small ubiquitin-like modifier
- Small molecules
- TPR2A, tetratricopeptide-containing repeat 2A
- TRAP1, Hsp75tumor necrosis factor receptor associated protein 1
- TROSY, transverse relaxation-optimized spectroscopy
- hERG, human ether-à-go-go-related gene
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Sanchez JN, Subramanian C, Chanda M, Gary S, Zhang N, Wang T, Timmermann BN, Blagg BS, Cohen MS. A novel C-terminal Hsp90 inhibitor KU758 synergizes efficacy in combination with BRAF or MEK inhibitors and targets drug-resistant pathways in BRAF-mutant melanomas. Melanoma Res 2021; 31:197-207. [PMID: 33904516 PMCID: PMC10565508 DOI: 10.1097/cmr.0000000000000734] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Melanoma remains the most aggressive and fatal form of skin cancer, despite several FDA-approved targeted chemotherapies and immunotherapies for use in advanced disease. Of the 100 350 new patients diagnosed with melanoma in 2020 in the US, more than half will develop metastatic disease leading to a 5-year survival rate <30%, with a majority of these developing drug-resistance within the first year of treatment. These statistics underscore the critical need in the field to develop more durable therapeutics as well as those that can overcome chemotherapy-induced drug resistance from currently approved agents. Fortunately, several of the drug-resistance pathways in melanoma, including the proteins in those pathways, rely in part on Hsp90 chaperone function. This presents a unique and novel opportunity to simultaneously target multiple proteins and drug-resistant pathways in this disease via molecular chaperone inhibition. Taken together, we hypothesize that our novel C-terminal Hsp90 inhibitor, KU758, in combination with the current standard of care targeted therapies (e.g. vemurafenib and cobimetinib) can both synergize melanoma treatment efficacy in BRAF-mutant tumors, as well as target and overcome several major resistance pathways in this disease. Using in vitro proliferation and protein-based Western Blot analyses, our novel inhibitor, KU758, potently inhibited melanoma cell proliferation (without induction of the heat shock response) in vitro and synergized with both BRAF and MEK inhibitors in inhibition of cell migration and protein expression from resistance pathways. Overall, our work provides early support for further translation of C-terminal Hsp90 inhibitor and mitogen-activated protein kinase pathway inhibitor combinations as a novel therapeutic strategy for BRAF-mutant melanomas.
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Affiliation(s)
- Jackee N. Sanchez
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan
| | | | - Monica Chanda
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan
| | - Shanguan Gary
- Department of Surgery, University of Michigan, Ann Arbor, Michigan
| | - Nina Zhang
- Department of Surgery, University of Michigan, Ann Arbor, Michigan
| | - Ton Wang
- Department of Surgery, University of Michigan, Ann Arbor, Michigan
| | | | - Brian S.J. Blagg
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana
| | - Mark S. Cohen
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan
- Department of Surgery, University of Michigan, Ann Arbor, Michigan
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5
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Keegan BM, Koren J, Blagg BS. Disruptors of the Hsp90/Aha1 complex that reduce tau aggregation. Alzheimers Dement 2020. [DOI: 10.1002/alz.045193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - John Koren
- University of Notre Dame Notre Dame IN USA
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6
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Jackson JW, Rivera-Marquez GM, Beebe K, Tran AD, Trepel JB, Gestwicki JE, Blagg BS, Ohkubo S, Neckers LM. Pharmacologic dissection of the overlapping impact of heat shock protein family members on platelet function. J Thromb Haemost 2020; 18:1197-1209. [PMID: 32022992 PMCID: PMC7497839 DOI: 10.1111/jth.14758] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 01/16/2020] [Accepted: 02/03/2020] [Indexed: 01/18/2023]
Abstract
BACKGROUND Platelets play a pivotal role in hemostasis, wound healing, and inflammation, and are thus implicated in a variety of diseases, including cancer. Platelet function is associated with release of granule content, cellular shape change, and upregulation of receptors that promote establishment of a thrombus and maintenance of hemostasis. OBJECTIVES The role of heat shock proteins (Hsps) in modulating platelet function has been studied for a number of years, but comparative roles of individual Hsps have not been thoroughly examined. METHODS We utilized a panel of specific inhibitors of Hsp40, Hsp70, Hsp90, and Grp94 (the endoplasmic reticulum homolog of Hsp90) to assess their impact on several aspects of platelet function. RESULTS Inhibition of each of the aforementioned Hsps reduced alpha granule release. In contrast, there was some selectivity in impacts on dense granule release. Thromboxane synthesis was impaired after exposure to inhibitors of Hsp40, Hsp90, and Grp94, but not after inhibition of Hsp70. Both expression of active glycoprotein IIb/IIIa (GPIIb/IIIa) and fibrinogen-induced platelet shape change were diminished by our inhibitors. In contrast, aggregation was selectively abrogated after inhibition of Hsp40 or Hsp90. Lastly, activated platelet-cancer cell interactions were reduced by inhibition of both Hsp70 and Grp94. CONCLUSIONS These data suggest the importance of Hsp networks in regulating platelet activity.
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Affiliation(s)
- Joseph W. Jackson
- Urologic Oncology Branch, Center for Cancer Research,
National Cancer Institute, NIH, Bethesda, Maryland
| | - Genesis M. Rivera-Marquez
- Urologic Oncology Branch, Center for Cancer Research,
National Cancer Institute, NIH, Bethesda, Maryland
| | - Kristin Beebe
- Urologic Oncology Branch, Center for Cancer Research,
National Cancer Institute, NIH, Bethesda, Maryland
| | - Andy D. Tran
- Confocal Microscopy Core Facility, Center for Cancer
Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - Jane B. Trepel
- Developmental Therapeutics Branch, Center for Cancer
Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - Jason E. Gestwicki
- Department of Pharmaceutical Chemistry and the
Institute for Neurodegenerative Disease, University of California at San Francisco,
San Francisco, California
| | - Brian S.J. Blagg
- Department of Chemistry and Biochemistry, The
University of Notre Dame, Notre Dame, Illinois
| | - Shuichi Ohkubo
- Tsukuba Research Center, Taiho
Pharmaceutical Co., Ltd., Tsukuba, Ibaraki, Japan
| | - Leonard M. Neckers
- Urologic Oncology Branch, Center for Cancer Research,
National Cancer Institute, NIH, Bethesda, Maryland
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7
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Shelton LB, Baker JD, Zheng D, Ghosh S, Blagg BS, Dickey CA, Blair LJ. [O2–03–05]: AHA1 ACCELERATES HSP90 ATPASE ACTIVITY TO DRIVE TAU AGGREGATION. Alzheimers Dement 2017. [DOI: 10.1016/j.jalz.2017.07.159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Lindsey B. Shelton
- University of South FloridaTampaFLUSA
- The University of KansasLawrenceKSUSA
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8
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Zhao H, Michaelis ML, Blagg BS. Hsp90 Modulation for the Treatment of Alzheimer’s Disease. Current State of Alzheimer's Disease Research and Therapeutics 2012; 64:1-25. [DOI: 10.1016/b978-0-12-394816-8.00001-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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9
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Penn HA, Manthe CA, Comer SB, Vielhauer GA, Rajewski RJ, Blagg BS, Holzbeierlein JM. 696 CHARACTERIZATION OF A C-TERMINAL HEAT SHOCK PROTEIN 90 INHIBITOR IN PROSTATE CANCER CELLS. J Urol 2010. [DOI: 10.1016/j.juro.2010.02.1095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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10
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Samadi AK, Mukerji R, Blagg BS, Cohen MS. Abstract A214: A novobiocin analogue HSP90 inhibitor induces apoptosis and has potent antitumor effects in head and neck squamous cell cancer in vivo. Mol Cancer Ther 2009. [DOI: 10.1158/1535-7163.targ-09-a214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Introduction: Small molecule n-terminal inhibitors of heat shock protein 90 (HSP90i) have been evaluated as anticancer agents in various stages of human clinical trials. This study evaluates a novel C-terminal HSP90 inhibitor derived as an analogue of novobiocin for its anti-tumor activity against head and neck squamous cell carcinoma (HNSCC) in vitro and in vivo.
Methods: Head and neck squamous cell carcinoma cells MDA1986 and JMAR were used to examine the efficacy of KU174 as an anti-cancer agent. Cell viability assay MTS and cell proliferation analysis were used to examine the concentration-dependent effect of KU174 on HNSCC cells. Cells were stained with propidium iodide and evaluated on flow cytometry (FC) to study the effects on cell cycle progression. Analysis of KU174 - induced apoptosis of HNSCC was evaluated first by annexin V/PI staining on FC after treatment with drug and confirmed by Western blot analysis for caspase activation and PARP cleavage. KU174 - induced modulation of kinases Akt and ERK1/2 was studied using Western blot analysis for levels of protein expression following treatment. Finally in vivo efficacy of KU174 was evaluated in an orthotopic mouse model of HNSCC following 3 weeks of daily i.p. injection with 5 mg/kg/d of drug.
Results: KU174 inhibited cell viability in both MDA1986 and JMAR cells (IC50 = 7.5 and 4.3 M respectively; novobiocin IC50>700 M for each; p<0.01). In addition, treatment of JMAR and MDA1986 cells by KU174 induced a 30% shift from G0/G1 arrest to G2/M cell cycle arrest. Cells treated with KU174 strongly stained with annexin V/PI indicating induction of apoptosis in these cells, quantitatively measured on FC at 80% with <3% necrosis. Apoptosis was confirmed by Western blot analysis demonstrating induced activation of caspase 3 and cleavage of PARP substrate in MDA1986 cells treated with KU174. HSP90 levels are reduced with drug treatment and both cell lines demonstrated downregulation of Akt activation without significant activation of ERK1/2. In vivo efficacy analysis demonstrates an 80% response rate with a 60% sustained complete response with treatment. Ex vivo immunohistochemistry staining indicate caspase 3 cleavage in animal tumor cells validating the role of apoptosis induction by this inhibitor.
Conclusion: These results show that the c-terminal HSP90 inhibitor KU174 is significantly more potent in antiproliferative activity in HNSCC cells than its parent compound novobiocin. Mechanistic studies suggest that the HNSCC cells treated with KU174 are likely dying by a combination of apoptosis, cell cycle arrest and modulation of proteins such as prosurvival kinases chaperoned by HSP90. Additionally this compound has potent antitumor efficacy in an orthotopic mouse model of HNSCC in vivo lending support for future preclinical proof-of-concept studies to translate its application as a potential human therapy in HNSCC.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):A214.
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Affiliation(s)
| | | | | | - Mark S. Cohen
- 1 University of Kansas Medical Center, Kansas City, KS
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11
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Tash JS, Chakrasali R, Jakkaraj SR, Hughes J, Smith SK, Hornbaker K, Heckert LL, Ozturk SB, Hadden MK, Kinzy TG, Blagg BS, Georg GI. Gamendazole, an Orally Active Indazole Carboxylic Acid Male Contraceptive Agent, Targets HSP90AB1 (HSP90BETA) and EEF1A1 (eEF1A), and Stimulates Il1a Transcription in Rat Sertoli Cells1. Biol Reprod 2008; 78:1139-52. [DOI: 10.1095/biolreprod.107.062679] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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13
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Hahn FM, Eubanks LM, Testa CA, Blagg BS, Baker JA, Poulter CD. 1-Deoxy-D-xylulose 5-phosphate synthase, the gene product of open reading frame (ORF) 2816 and ORF 2895 in Rhodobacter capsulatus. J Bacteriol 2001; 183:1-11. [PMID: 11114895 PMCID: PMC94844 DOI: 10.1128/jb.183.1.1-11.2001] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In eubacteria, green algae, and plant chloroplasts, isopentenyl diphosphate, a key intermediate in the biosynthesis of isoprenoids, is synthesized by the methylerythritol phosphate pathway. The five carbons of the basic isoprenoid unit are assembled by joining pyruvate and D-glyceraldehyde 3-phosphate. The reaction is catalyzed by the thiamine diphosphate-dependent enzyme 1-deoxy-D-xylulose 5-phosphate synthase. In Rhodobacter capsulatus, two open reading frames (ORFs) carry the genes that encode 1-deoxy-D-xylulose 5-phosphate synthase. ORF 2816 is located in the photosynthesis-related gene cluster, along with most of the genes required for synthesis of the photosynthetic machinery of the bacterium, whereas ORF 2895 is located elsewhere in the genome. The proteins encoded by ORF 2816 and ORF 2895, 1-deoxy-D-xylulose 5-phosphate synthase A and B, containing a His(6) tag, were synthesized in Escherichia coli and purified to greater than 95% homogeneity in two steps. 1-Deoxy-D-xylulose 5-phosphate synthase A appears to be a homodimer with 68 kDa subunits. A new assay was developed, and the following steady-state kinetic constants were determined for 1-deoxy-D-xylulose 5-phosphate synthase A and B: K(m)(pyruvate) = 0.61 and 3.0 mM, K(m)(D-glyceraldehyde 3-phosphate) = 150 and 120 microM, and V(max) = 1.9 and 1.4 micromol/min/mg in 200 mM sodium citrate (pH 7.4). The ORF encoding 1-deoxy-D-xylulose 5-phosphate synthase B complemented the disrupted essential dxs gene in E. coli strain FH11.
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Affiliation(s)
- F M Hahn
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
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14
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Koppisch AT, Blagg BS, Poulter CD. Synthesis of 2-C-methyl-D-erythritol 4-phosphate: the first pathway-specific intermediate in the methylerythritol phosphate route to isoprenoids. Org Lett 2000; 2:215-7. [PMID: 10814285 DOI: 10.1021/ol991299x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] 2-C-methyl-D-erythritol 4-phosphate (4), formed from 1-deoxy-D-xylulose 5-phosphate (3), is the first pathway-specific intermediate in the methylerythritol phosphate route for the biosynthesis of isoprenoid compounds in bacteria, algae, and plant chloroplasts. In this report, 4 was synthesized from 1,2-propanediol (7) in seven steps with an overall yield of 32% and in an enantiomeric excess of 78%.
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Affiliation(s)
- A T Koppisch
- Department of Chemistry, University of Utah, Salt Lake City 84112, USA
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