1
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Sun C, Li S, Ding J. Biomaterials-Boosted Immunotherapy for Osteosarcoma. Adv Healthc Mater 2024:e2400864. [PMID: 38771618 DOI: 10.1002/adhm.202400864] [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: 03/06/2024] [Revised: 05/05/2024] [Indexed: 05/22/2024]
Abstract
Osteosarcoma (OS) is a primary malignant bone tumor that emanates from mesenchymal cells, commonly found in the epiphyseal end of long bones. The highly recurrent and metastatic nature of OS poses significant challenges to the efficacy of treatment and negatively affects patient prognosis. Currently, available clinical treatment strategies primarily focus on maximizing tumor resection and reducing localized symptoms rather than the complete eradication of malignant tumor cells to achieve ideal outcomes. The biomaterials-boosted immunotherapy for OS is characterized by high effectiveness and a favorable safety profile. This therapeutic approach manipulates the tumor microenvironments at the cellular and molecular levels to impede tumor progression. This review delves into the mechanisms underlying the treatment of OS, emphasizing biomaterials-enhanced tumor immunity. Moreover, it summarizes the immune cell phenotype and tumor microenvironment regulation, along with the ability of immune checkpoint blockade to activate the autoimmune system. Gaining a profound comprehension of biomaterials-boosted OS immunotherapy is imperative to explore more efficacious immunotherapy protocols and treatment options in this setting.
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Affiliation(s)
- Chao Sun
- Department of Orthopedic Surgery, Orthopedic Center, The First Hospital of Jilin University, 1 Xinmin Street, Changchun, 130061, P. R. China
- Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun, 130022, P. R. China
| | - Shuqiang Li
- Department of Orthopedic Surgery, Orthopedic Center, The First Hospital of Jilin University, 1 Xinmin Street, Changchun, 130061, P. R. China
| | - Jianxun Ding
- Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun, 130022, P. R. China
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2
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Faulkner RA, Yang Y, Tsien J, Qin T, DeBose-Boyd RA. Direct binding to sterols accelerates endoplasmic reticulum-associated degradation of HMG CoA reductase. Proc Natl Acad Sci U S A 2024; 121:e2318822121. [PMID: 38319967 PMCID: PMC10873557 DOI: 10.1073/pnas.2318822121] [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: 10/27/2023] [Accepted: 01/09/2024] [Indexed: 02/08/2024] Open
Abstract
The maintenance of cholesterol homeostasis is crucial for normal function at both the cellular and organismal levels. Two integral membrane proteins, 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) and Scap, are key targets of a complex feedback regulatory system that operates to ensure cholesterol homeostasis. HMGCR catalyzes the rate-limiting step in the transformation of the 2-carbon precursor acetate to 27-carbon cholesterol. Scap mediates proteolytic activation of sterol regulatory element-binding protein-2 (SREBP-2), a membrane-bound transcription factor that controls expression of genes involved in the synthesis and uptake of cholesterol. Sterol accumulation triggers binding of HMGCR to endoplasmic reticulum (ER)-localized Insig proteins, leading to the enzyme's ubiquitination and proteasome-mediated ER-associated degradation (ERAD). Sterols also induce binding of Insigs to Scap, which leads to sequestration of Scap and its bound SREBP-2 in the ER, thereby preventing proteolytic activation of SREBP-2 in the Golgi. The oxygenated cholesterol derivative 25-hydroxycholesterol (25HC) and the methylated cholesterol synthesis intermediate 24,25-dihydrolanosterol (DHL) differentially modulate HMGCR and Scap. While both sterols promote binding of HMGCR to Insigs for ubiquitination and subsequent ERAD, only 25HC inhibits the Scap-mediated proteolytic activation of SREBP-2. We showed previously that 1,1-bisphosphonate esters mimic DHL, accelerating ERAD of HMGCR while sparing SREBP-2 activation. Building on these results, our current studies reveal specific, Insig-independent photoaffinity labeling of HMGCR by photoactivatable derivatives of the 1,1-bisphosphonate ester SRP-3042 and 25HC. These findings disclose a direct sterol binding mechanism as the trigger that initiates the HMGCR ERAD pathway, providing valuable insights into the intricate mechanisms that govern cholesterol homeostasis.
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Affiliation(s)
- Rebecca A. Faulkner
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390-9046
| | - Yangyan Yang
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX75390-9046
| | - Jet Tsien
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX75390-9046
| | - Tian Qin
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX75390-9046
| | - Russell A. DeBose-Boyd
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390-9046
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3
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Kawamura K, Yoshioka H, Sato C, Yajima T, Furuyama Y, Kuramochi K, Ohgane K. Fine-tuning of nitrogen-containing bisphosphonate esters that potently induce degradation of HMG-CoA reductase. Bioorg Med Chem 2023; 78:117145. [PMID: 36580745 DOI: 10.1016/j.bmc.2022.117145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 12/20/2022] [Accepted: 12/20/2022] [Indexed: 12/25/2022]
Abstract
3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase is the rate-limiting enzyme in the cholesterol biosynthetic pathway, and competitive inhibitors targeting the catalytic domain of this enzyme, so-called statins, are widely used for the treatment of hyperlipidemia. The membrane domain mediates the sterol-accelerated degradation, a post-translational negative feedback mechanism, and small molecules triggering such degradation have been studied as an alternative therapeutic option. Such strategies are expected to provide benefits over catalytic site inhibitors, as the inhibition leads to transcriptional and post-translational upregulation of the enzyme, necessitating a higher dose of the inhibitors and concomitantly increasing the risk of serious adverse effects, including myopathies. Through our previous study on SR12813, a synthetic small molecule that induces degradation of HMG-CoA reductase, we identified a nitrogen-containing bisphosphonate ester SRP3042 as a highly potent HMG-CoA reductase degrader. Here, we performed a systematic structure-activity relationship study to optimize its activity and physicochemical properties, specifically focusing on the reduction of lipophilicity. Mono-fluorination of tert-butyl groups on the molecules was found to increase the HMG-CoA reductase degradation activity while reducing lipophilicity, suggesting the mono-fluorination of saturated alkyl groups as a useful strategy to balance potency and lipophilicity of the lead compounds.
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Affiliation(s)
- Kota Kawamura
- Department of Applied Bioscience, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8519, Japan
| | - Hiromasa Yoshioka
- Institute for Quantitative Biosciences, The University of Tokyo, 1-1 Yayoi, Bunkyo, Tokyo 13-0032, Japan
| | - Chikako Sato
- Department of Chemistry, Ochanomizu University, 2-1-1 Otsuka, Bunkyo, Tokyo 112-8610, Japan
| | - Tomoko Yajima
- Department of Chemistry, Ochanomizu University, 2-1-1 Otsuka, Bunkyo, Tokyo 112-8610, Japan
| | - Yuuki Furuyama
- Department of Applied Bioscience, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8519, Japan
| | - Kouji Kuramochi
- Department of Applied Bioscience, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8519, Japan
| | - Kenji Ohgane
- Department of Applied Bioscience, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8519, Japan; Department of Chemistry, Ochanomizu University, 2-1-1 Otsuka, Bunkyo, Tokyo 112-8610, Japan.
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4
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Ebetino FH, Sun S, Cherian P, Roshandel S, Neighbors JD, Hu E, Dunford JE, Sedghizadeh PP, McKenna CE, Srinivasan V, Boeckman RK, Russell RGG. Bisphosphonates: The role of chemistry in understanding their biological actions and structure-activity relationships, and new directions for their therapeutic use. Bone 2022; 156:116289. [PMID: 34896359 PMCID: PMC11023620 DOI: 10.1016/j.bone.2021.116289] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 11/16/2021] [Accepted: 12/03/2021] [Indexed: 12/13/2022]
Abstract
The bisphosphonates ((HO)2P(O)CR1R2P(O)(OH)2, BPs) were first shown to inhibit bone resorption in the 1960s, but it was not until 30 years later that a detailed molecular understanding of the relationship between their varied chemical structures and biological activity was elucidated. In the 1990s and 2000s, several potent bisphosphonates containing nitrogen in their R2 side chains (N-BPs) were approved for clinical use including alendronate, risedronate, ibandronate, and zoledronate. These are now mostly generic drugs and remain the leading therapies for several major bone-related diseases, including osteoporosis and skeletal-related events associated with bone metastases. The early development of chemistry in this area was largely empirical and only a few common structural features related to strong binding to calcium phosphate were clear. Attempts to further develop structure-activity relationships to explain more dramatic pharmacological differences in vivo at first appeared inconclusive, and evidence for mechanisms underlying cellular effects on osteoclasts and macrophages only emerged after many years of research. The breakthrough came when the intracellular actions on the osteoclast were first shown for the simpler bisphosphonates, via the in vivo formation of P-C-P derivatives of ATP. The synthesis and biological evaluation of a large number of nitrogen-containing bisphosphonates in the 1980s and 1990s led to the key discovery that the antiresorptive effects of these more complex analogs on osteoclasts result mostly from their potency as inhibitors of the enzyme farnesyl diphosphate synthase (FDPS/FPPS). This key branch-point enzyme in the mevalonate pathway of cholesterol biosynthesis is important for the generation of isoprenoid lipids that are utilized for the post-translational modification of small GTP-binding proteins essential for osteoclast function. Since then, it has become even more clear that the overall pharmacological effects of individual bisphosphonates on bone depend upon two key properties: the affinity for bone mineral and inhibitory effects on biochemical targets within bone cells, in particular FDPS. Detailed enzyme-ligand crystal structure analysis began in the early 2000s and advances in our understanding of the structure-activity relationships, based on interactions with this target within the mevalonate pathway and related enzymes in osteoclasts and other cells have continued to be the focus of research efforts to this day. In addition, while many members of the bisphosphonate drug class share common properties, now it is more clear that chemical modifications to create variations in these properties may allow customization of BPs for different uses. Thus, as the appreciation for new potential opportunities with this drug class grows, new chemistry to allow ready access to an ever-widening variety of bisphosphonates continues to be developed. Potential new uses of the calcium phosphate binding mechanism of bisphosphonates for the targeting of other drugs to the skeleton, and effects discovered on other cellular targets, even at non-skeletal sites, continue to intrigue scientists in this research field.
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Affiliation(s)
- Frank H Ebetino
- BioVinc LLC, 2265 E. Foothill Blvd, Pasadena, CA 91107, USA; Department of Chemistry, University of Rochester, Rochester, NY 14617, USA; Department of Oncology & Metabolism, University of Sheffield, Sheffield, UK.
| | - Shuting Sun
- BioVinc LLC, 2265 E. Foothill Blvd, Pasadena, CA 91107, USA.
| | - Philip Cherian
- BioVinc LLC, 2265 E. Foothill Blvd, Pasadena, CA 91107, USA
| | | | | | - Eric Hu
- BioVinc LLC, 2265 E. Foothill Blvd, Pasadena, CA 91107, USA
| | - James E Dunford
- Nuffield Department of Orthopaedics, Rheumatology & Musculoskeletal Sciences, The Oxford University Institute of Musculoskeletal Sciences, The Botnar Research Centre, Nuffield Orthopaedic Centre, Headington, Oxford OX3 7LD, UK
| | - Parish P Sedghizadeh
- Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA 90089, USA
| | - Charles E McKenna
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA
| | - Venkat Srinivasan
- Department of Chemistry, University of Rochester, Rochester, NY 14617, USA
| | - Robert K Boeckman
- Department of Chemistry, University of Rochester, Rochester, NY 14617, USA
| | - R Graham G Russell
- Department of Oncology & Metabolism, University of Sheffield, Sheffield, UK; Nuffield Department of Orthopaedics, Rheumatology & Musculoskeletal Sciences, The Oxford University Institute of Musculoskeletal Sciences, The Botnar Research Centre, Nuffield Orthopaedic Centre, Headington, Oxford OX3 7LD, UK; Mellanby Centre for Musculoskeletal Research, University of Sheffield, Sheffield, UK
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5
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Gesto DS, Pereira CMS, Cerqueira NMFS, Sousa SF. An Atomic-Level Perspective of HMG-CoA-Reductase: The Target Enzyme to Treat Hypercholesterolemia. Molecules 2020; 25:molecules25173891. [PMID: 32859023 PMCID: PMC7503714 DOI: 10.3390/molecules25173891] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 08/23/2020] [Accepted: 08/24/2020] [Indexed: 12/19/2022] Open
Abstract
This review provides an updated atomic-level perspective regarding the enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoAR), linking the more recent data on this enzyme with a structure/function interpretation. This enzyme catalyzes one of the most important steps in cholesterol biosynthesis and is regarded as one of the most important drug targets in the treatment of hypercholesterolemia. Taking this into consideration, we review in the present article several aspects of this enzyme, including its structure and biochemistry, its catalytic mechanism and different reported and proposed approaches for inhibiting this enzyme, including the commercially available statins or the possibility of using dimerization inhibitors.
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Affiliation(s)
- Diana S. Gesto
- UCIBIO, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal;
| | - Carlos M. S. Pereira
- UCIBIO/REQUIMTE, BioSIM, Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal; (C.M.S.P.); (N.M.F.S.C.)
| | - Nuno M. F. S. Cerqueira
- UCIBIO/REQUIMTE, BioSIM, Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal; (C.M.S.P.); (N.M.F.S.C.)
| | - Sérgio F. Sousa
- UCIBIO/REQUIMTE, BioSIM, Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal; (C.M.S.P.); (N.M.F.S.C.)
- Correspondence:
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6
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Toyota Y, Yoshioka H, Sagimori I, Hashimoto Y, Ohgane K. Bisphosphonate esters interact with HMG-CoA reductase membrane domain to induce its degradation. Bioorg Med Chem 2020; 28:115576. [PMID: 32616181 DOI: 10.1016/j.bmc.2020.115576] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 05/24/2020] [Accepted: 05/26/2020] [Indexed: 12/16/2022]
Abstract
HMG-CoA reductase (HMGCR) is a rate-limiting enzyme in the cholesterol biosynthetic pathway, and its catalytic domain is the well-known target of cholesterol-lowering drugs, statins. HMGCR is subject to layers of negative feedback loops; excess cholesterol inhibits transcription of the gene, and lanosterols and oxysterols accelerate degradation of HMGCR. A class of synthetic small molecules, bisphosphonate esters exemplified by SR12813, has been known to induce accelerated degradation of HMGCR and reduce the serum cholesterol level. Although genetic and biochemical studies revealed that the accelerated degradation requires the membrane domain of HMGCR and Insig, an oxysterol sensor on the endoplasmic reticulum membrane, the direct target of the bisphosphonate esters remains unclear. In this study, we developed a potent photoaffinity probe of the bisphosphonate esters through preliminary structure-activity relationship study and demonstrated binding of the bisphosphonate esters to the HMGCR membrane domain. These results provide an important clue to understand the elusive mechanism of the SR12813-mediated HMGCR degradation and serve as a basis to develop more potent HMGCR degraders that target the non-catalytic, membrane domain of the enzyme.
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Affiliation(s)
- Yosuke Toyota
- Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113 0032, Japan
| | - Hiromasa Yoshioka
- Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113 0032, Japan
| | - Ikuya Sagimori
- Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113 0032, Japan
| | - Yuichi Hashimoto
- Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113 0032, Japan
| | - Kenji Ohgane
- Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113 0032, Japan.
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7
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Sagimori I, Yoshioka H, Hashimoto Y, Ohgane K. Luciferase-based HMG-CoA reductase degradation assay for activity and selectivity profiling of oxy(lano)sterols. Bioorg Med Chem 2020; 28:115298. [PMID: 31902650 DOI: 10.1016/j.bmc.2019.115298] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/21/2019] [Accepted: 12/25/2019] [Indexed: 11/18/2022]
Abstract
HMG-CoA reductase (HMGCR) is the rate-limiting enzyme in the cholesterol biosynthetic pathway, and is the target of cholesterol-lowering drugs, statins. Previous studies have demonstrated that the enzyme activity is regulated by sterol-induced degradation in addition to transcriptional regulation through sterol-regulatory-element-binding proteins (SREBPs). While 25-hydroxycholesterol induces both HMGCR degradation and SREBP inhibition in a nonselective manner, lanosterol selectively induces HMGCR degradation. Here, to clarify the structural determinants of selectivity for the two activities, we established a luciferase-based assay monitoring HMGCR degradation and used it to profile the structure-activity/selectivity relationships of oxysterols and (oxy)lanosterols. We identified several sterols that selectively induce HMGCR degradation and one sterol, 25-hydroxycholest-4-en-3-one, that selectively inhibits the SREBP pathway. These results should be helpful in designing more potent and selective HMGCR degraders.
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Affiliation(s)
- Ikuya Sagimori
- Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Hiromasa Yoshioka
- Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Yuichi Hashimoto
- Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Kenji Ohgane
- Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
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8
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Becker CS, Chukanov NV, Grigor’ev IA. New Amino-Bisphosphonate Building Blocks in the Synthesis of Bisphosphonic Derivatives Based on Lead Compounds. PHOSPHORUS SULFUR 2015. [DOI: 10.1080/10426507.2014.979989] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Christina S. Becker
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Novosibirsk, Russian Federation
- Novosibirsk State University, Novosibirsk, Russian Federation
| | - Nikita V. Chukanov
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Novosibirsk, Russian Federation
- Novosibirsk State University, Novosibirsk, Russian Federation
| | - Igor A. Grigor’ev
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Novosibirsk, Russian Federation
- Academician E.N. Meshalkin State Research Institute of Circulation Pathology, Novosibirsk, Russian Federation
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9
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Schumacher MM, Elsabrouty R, Seemann J, Jo Y, DeBose-Boyd RA. The prenyltransferase UBIAD1 is the target of geranylgeraniol in degradation of HMG CoA reductase. eLife 2015; 4. [PMID: 25742604 PMCID: PMC4374513 DOI: 10.7554/elife.05560] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 03/04/2015] [Indexed: 01/18/2023] Open
Abstract
Schnyder corneal dystrophy (SCD) is an autosomal dominant disorder in humans characterized by abnormal accumulation of cholesterol in the cornea. SCD-associated mutations have been identified in the gene encoding UBIAD1, a prenyltransferase that synthesizes vitamin K2. Here, we show that sterols stimulate binding of UBIAD1 to the cholesterol biosynthetic enzyme HMG CoA reductase, which is subject to sterol-accelerated, endoplasmic reticulum (ER)-associated degradation augmented by the nonsterol isoprenoid geranylgeraniol through an unknown mechanism. Geranylgeraniol inhibits binding of UBIAD1 to reductase, allowing its degradation and promoting transport of UBIAD1 from the ER to the Golgi. CRISPR-CAS9-mediated knockout of UBIAD1 relieves the geranylgeraniol requirement for reductase degradation. SCD-associated mutations in UBIAD1 block its displacement from reductase in the presence of geranylgeraniol, thereby preventing degradation of reductase. The current results identify UBIAD1 as the elusive target of geranylgeraniol in reductase degradation, the inhibition of which may contribute to accumulation of cholesterol in SCD. DOI:http://dx.doi.org/10.7554/eLife.05560.001 People with a rare genetic disorder called ‘Schnyder corneal dystrophy’ gradually lose their vision, because their corneas become increasingly cloudy. This cloudiness is caused by a build-up of excessive amounts of cholesterol, and the disorder itself is caused by mutations in a gene that encodes a protein called UBIAD1. Researchers have previously discovered that the UBIAD1 protein is involved in making vitamin K2, but it is not clear how this protein also helps to control cholesterol levels in the cornea. An enzyme called HMG CoA reductase makes a molecule that is used to make cholesterol and many other similar sterol molecules. A ‘feedback loop’ operates in cells to control the amount of the reductase and prevent cholesterol from becoming too high or too low. Sterol molecules, together with another molecule called geranylgeraniol, participate in this feedback loop by promoting the destruction of the reductase enzyme. Here, Schumacher et al. reveal a link between UBIAD1 and the reductase that may explain how UBIAD1 contributes to the production of excess cholesterol in patients with Schnyder corneal dystrophy. The experiments show that, in the presence of sterol molecules, UBIAD1 can bind to HMG CoA reductase to protect the reductase from being destroyed by other proteins. Geranylgeraniol—which stops the UBIAD1 protein from binding to the enzyme—is required to completely destroy the reductase enzyme. However, when UBIAD1 is missing, the reductase enzyme is destroyed even in the absence of geranylgeraniol. Furthermore, the experiments show that the genetic mutations linked to Schnyder corneal dystrophy lead to the production of versions of the UBIAD1 protein that bind to the reductase enzyme even when geranylgeraniol molecules are present. This prevents the normal breakdown of the reductase enzyme, which could lead to the build up of cholesterol in the cornea of individuals with the disorder. Schumacher et al.'s findings show that the UBIAD1 protein helps to control the levels of cholesterol in cells by protecting the HMG CoA reductase enzyme from destruction. These findings may aid the development of new therapies to lower cholesterol levels in cells, which may help patients with Schnyder's corneal dystrophy and other conditions caused by high cholesterol levels. DOI:http://dx.doi.org/10.7554/eLife.05560.002
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Affiliation(s)
- Marc M Schumacher
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States
| | - Rania Elsabrouty
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States
| | - Joachim Seemann
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Youngah Jo
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States
| | - Russell A DeBose-Boyd
- Department of Molecular Genetics, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, United States
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10
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Morris LL, Hartman IZ, Jun DJ, Seemann J, DeBose-Boyd RA. Sequential actions of the AAA-ATPase valosin-containing protein (VCP)/p97 and the proteasome 19 S regulatory particle in sterol-accelerated, endoplasmic reticulum (ER)-associated degradation of 3-hydroxy-3-methylglutaryl-coenzyme A reductase. J Biol Chem 2014; 289:19053-66. [PMID: 24860107 DOI: 10.1074/jbc.m114.576652] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Accelerated endoplasmic reticulum (ER)-associated degradation (ERAD) of the cholesterol biosynthetic enzyme 3-hydroxy-3-methylglutaryl-coenzyme A reductase results from its sterol-induced binding to ER membrane proteins called Insig-1 and Insig-2. This binding allows for subsequent ubiquitination of reductase by Insig-associated ubiquitin ligases. Once ubiquitinated, reductase becomes dislocated from ER membranes into the cytosol for degradation by 26 S proteasomes through poorly defined reactions mediated by the AAA-ATPase valosin-containing protein (VCP)/p97 and augmented by the nonsterol isoprenoid geranylgeraniol. Here, we report that the oxysterol 25-hydroxycholesterol and geranylgeraniol combine to trigger extraction of reductase across ER membranes prior to its cytosolic release. This conclusion was drawn from studies utilizing a novel assay that measures membrane extraction of reductase by determining susceptibility of a lumenal epitope in the enzyme to in vitro protease digestion. Susceptibility of the lumenal epitope to protease digestion and thus membrane extraction of reductase were tightly regulated by 25-hydroxycholesterol and geranylgeraniol. The reaction was inhibited by RNA interference-mediated knockdown of either Insigs or VCP/p97. In contrast, reductase continued to become membrane-extracted, but not cytosolically dislocated, in cells deficient for AAA-ATPases of the proteasome 19 S regulatory particle. These findings establish sequential roles for VCP/p97 and the 19 S regulatory particle in the sterol-accelerated ERAD of reductase that may be applicable to the ERAD of other substrates.
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Affiliation(s)
| | | | | | | | - Russell A DeBose-Boyd
- From the Departments of Molecular Genetics and the Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9046
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11
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Elsabrouty R, Jo Y, Dinh TT, DeBose-Boyd RA. Sterol-induced dislocation of 3-hydroxy-3-methylglutaryl coenzyme A reductase from membranes of permeabilized cells. Mol Biol Cell 2013; 24:3300-8. [PMID: 24025715 PMCID: PMC3814148 DOI: 10.1091/mbc.e13-03-0157] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
This study establishes permeabilized cells as a viable system in which to elucidate mechanisms for Insig-mediated, sterol-induced ubiquitination and subsequent dislocation of HMG CoA reductase from endoplasmic reticulum membranes into the cytosol for degradation by 26S proteasomes. The polytopic endoplasmic reticulum (ER)–localized enzyme 3-hydroxy-3-methylglutaryl CoA reductase catalyzes a rate-limiting step in the synthesis of cholesterol and nonsterol isoprenoids. Excess sterols cause the reductase to bind to ER membrane proteins called Insig-1 and Insig-2, which are carriers for the ubiquitin ligases gp78 and Trc8. The resulting gp78/Trc8-mediated ubiquitination of reductase marks it for recognition by VCP/p97, an ATPase that mediates subsequent dislocation of reductase from ER membranes into the cytosol for proteasomal degradation. Here we report that in vitro additions of the oxysterol 25-hydroxycholesterol (25-HC), exogenous cytosol, and ATP trigger dislocation of ubiquitinated and full-length forms of reductase from membranes of permeabilized cells. In addition, the sterol-regulated reaction requires the action of Insigs, is stimulated by reagents that replace 25-HC in accelerating reductase degradation in intact cells, and is augmented by the nonsterol isoprenoid geranylgeraniol. Finally, pharmacologic inhibition of deubiquitinating enzymes markedly enhances sterol-dependent ubiquitination of reductase in membranes of permeabilized cells, leading to enhanced dislocation of the enzyme. Considered together, these results establish permeabilized cells as a viable system in which to elucidate mechanisms for postubiquitination steps in sterol-accelerated degradation of reductase.
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Affiliation(s)
- Rania Elsabrouty
- Howard Hughes Medical Institute and Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046
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12
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Wrzesinski K, Fey SJ. After trypsinisation, 3D spheroids of C3A hepatocytes need 18 days to re-establish similar levels of key physiological functions to those seen in the liver. Toxicol Res (Camb) 2013. [DOI: 10.1039/c2tx20060k] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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13
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Tsai YC, Leichner GS, Pearce MMP, Wilson GL, Wojcikiewicz RJH, Roitelman J, Weissman AM. Differential regulation of HMG-CoA reductase and Insig-1 by enzymes of the ubiquitin-proteasome system. Mol Biol Cell 2012; 23:4484-94. [PMID: 23087214 PMCID: PMC3510011 DOI: 10.1091/mbc.e12-08-0631] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
HMGCR is subject to Insig-dependent, sterol-accelerated ERAD. gp78 was reported to target HMGCR and Insig-1 for ubiquitination and degradation. Here gp78-mediated Insig-1 degradation is confirmed, but no role for gp78 is found in regulated ERAD of HMGCR. The identity of the HMGCR E3(s) and mechanistic details of HMGCR degradation await further study. The endoplasmic reticulum (ER)–resident enzyme 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase catalyzes the rate-limiting step in sterol production and is the therapeutic target of statins. Understanding HMG-CoA reductase regulation has tremendous implications for atherosclerosis. HMG-CoA reductase levels are regulated in response to sterols both transcriptionally, through a complex regulatory loop involving the ER Insig proteins, and posttranslationally, by Insig-dependent protein degradation by the ubiquitin-proteasome system. The ubiquitin ligase (E3) gp78 has been implicated in the sterol-regulated degradation of HMG-CoA reductase and Insig-1 through ER-associated degradation (ERAD). More recently, a second ERAD E3, TRC8, has also been reported to play a role in the sterol-accelerated degradation of HMG-CoA reductase. We interrogated this network in gp78−/− mouse embryonic fibroblasts and also assessed two fibroblast cell lines using RNA interference. Although we consistently observe involvement of gp78 in Insig-1 degradation, we find no substantive evidence to support roles for either gp78 or TRC8 in the robust sterol-accelerated degradation of HMG-CoA reductase. We discuss factors that might lead to such discrepant findings. Our results suggest a need for additional studies before definitive mechanistic conclusions are drawn that might set the stage for development of drugs to manipulate gp78 function in metabolic disorders.
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Affiliation(s)
- Yien Che Tsai
- Laboratory of Protein Dynamics and Signaling, National Cancer Institute, Frederick, MD 20712, USA
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14
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Leichner GS, Avner R, Harats D, Roitelman J. Metabolically regulated endoplasmic reticulum-associated degradation of 3-hydroxy-3-methylglutaryl-CoA reductase: evidence for requirement of a geranylgeranylated protein. J Biol Chem 2011; 286:32150-61. [PMID: 21778231 PMCID: PMC3173168 DOI: 10.1074/jbc.m111.278036] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 07/18/2011] [Indexed: 11/06/2022] Open
Abstract
In mammalian cells, the enzyme 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR), which catalyzes the rate-limiting step in the mevalonate pathway, is ubiquitylated and degraded by the 26 S proteasome when mevalonate-derived metabolites accumulate, representing a case of metabolically regulated endoplasmic reticulum-associated degradation (ERAD). Here, we studied which mevalonate-derived metabolites signal for HMGR degradation and the ERAD step(s) in which these metabolites are required. In HMGR-deficient UT-2 cells that stably express HMGal, a chimeric protein between β-galactosidase and the membrane region of HMGR, which is necessary and sufficient for the regulated ERAD, we tested inhibitors specific to different steps in the mevalonate pathway. We found that metabolites downstream of farnesyl pyrophosphate but upstream to lanosterol were highly effective in initiating ubiquitylation, dislocation, and degradation of HMGal. Similar results were observed for endogenous HMGR in cells that express this protein. Ubiquitylation, dislocation, and proteasomal degradation of HMGal were severely hampered when production of geranylgeranyl pyrophosphate was inhibited. Importantly, inhibition of protein geranylgeranylation markedly attenuated ubiquitylation and dislocation, implicating for the first time a geranylgeranylated protein(s) in the metabolically regulated ERAD of HMGR.
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Affiliation(s)
- Gil S. Leichner
- From the Department of Human Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978 and
- the Bert W. Strassburger Lipid Center, Sheba Medical Center, Tel Hashomer 52621, Israel
| | - Rachel Avner
- the Bert W. Strassburger Lipid Center, Sheba Medical Center, Tel Hashomer 52621, Israel
| | - Dror Harats
- the Bert W. Strassburger Lipid Center, Sheba Medical Center, Tel Hashomer 52621, Israel
| | - Joseph Roitelman
- From the Department of Human Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978 and
- the Bert W. Strassburger Lipid Center, Sheba Medical Center, Tel Hashomer 52621, Israel
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15
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Moriceau G, Roelofs AJ, Brion R, Redini F, Ebetion FH, Rogers MJ, Heymann D. Synergistic inhibitory effect of apomine and lovastatin on osteosarcoma cell growth. Cancer 2011; 118:750-60. [DOI: 10.1002/cncr.26336] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Revised: 05/16/2011] [Accepted: 05/16/2011] [Indexed: 11/07/2022]
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16
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Gamble RG, Jensen D, Suarez AL, Hanson AH, McLaughlin L, Duke J, Dellavalle RP. Outpatient Follow-up and Secondary Prevention for Melanoma Patients. Cancers (Basel) 2010; 2:1178-97. [PMID: 24281112 PMCID: PMC3835125 DOI: 10.3390/cancers2021178] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Revised: 06/02/2010] [Accepted: 06/03/2010] [Indexed: 02/07/2023] Open
Abstract
Health care providers and their patients jointly participate in melanoma prevention, surveillance, diagnosis, and treatment. This paper reviews screening and follow-up strategies for patients who have been diagnosed with melanoma, based on current available evidence, and focuses on methods to assess disease recurrence and second primary occurrence. Secondary prevention, including the roles of behavioral modification and chemoprevention are also reviewed. The role of follow-up dermatologist consultation, with focused physical examinations complemented by dermatoscopy, reflectance confocal microscopy, and/or full-body mapping is discussed. Furthermore, we address the inclusion of routine imaging and laboratory assessment as components of follow-up and monitoring of advanced stage melanoma. The role of physicians in addressing the psychosocial stresses associated with a diagnosis of melanoma is reviewed.
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Affiliation(s)
- Ryan G. Gamble
- Department of Dermatology, University of Colorado Denver, Aurora, CO, USA; E-Mail: (R.G.G.); (J.D.J.)
| | - Daniel Jensen
- Department of Dermatology, University of Colorado Denver, Aurora, CO, USA; E-Mail: (R.G.G.); (J.D.J.)
| | - Andrea L. Suarez
- Department of Dermatology, University of Colorado Denver, Aurora, CO, USA; E-Mail: (R.G.G.); (J.D.J.)
| | - Anne H. Hanson
- Kansas City University of Medicine and Biosciences, Kansas City, MO, USA; E-Mail:
| | - Lauren McLaughlin
- Rocky Vista University College of Osteopathic Medicine, Parker, CO, USA; E-Mail:
| | - Jodi Duke
- Department of Dermatology, University of Colorado Denver, Aurora, CO, USA; E-Mail: (R.G.G.); (J.D.J.)
- School of Pharmacy, University of Colorado, Aurora, CO, USA; E-Mail:
| | - Robert P. Dellavalle
- Department of Dermatology, University of Colorado Denver, Aurora, CO, USA; E-Mail: (R.G.G.); (J.D.J.)
- Dermatology Service, Denver Veterans Affairs Medical Center, Denver, CO, USA
- Epidemiology Department, Colorado School of Public Health, Aurora, CO, USA
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17
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Cho K, Kim SJ, Park SH, Kim S, Park T. Protective effect of Codonopsis lanceolata root extract against alcoholic fatty liver in the rat. J Med Food 2010; 12:1293-301. [PMID: 20041784 DOI: 10.1089/jmf.2009.0085] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Alcohol intake remains the most important cause of fatty liver throughout the world. The current study was undertaken to determine whether dietary supplementation with Codonopsis lanceolata root water extract attenuates the development of alcoholic fatty liver in rats and to elucidate the molecular mechanism for such an effect. Male Sprague-Dawley rats were fed normal diet (ND), ethanol diet (ED) (36% of total energy from ethanol), or 0.5% C. lanceolata root extract-supplemented ethanol diet (ED+C) for 8 weeks. C. lanceolata root water extract supplemented to rats with chronic alcohol consumption ameliorated the ethanol-induced accumulations of hepatic cholesterol and triglyceride. Chronic alcohol consumption up-regulated the hepatic expression of genes involved in inflammation, fatty acid synthesis, and cholesterol metabolism, including tumor necrosis factor alpha (TNFalpha), liver X receptor alpha (LXRalpha), sterol regulatory element-binding protein (SREBP)-1c, fatty acid synthase, acetyl-coenzyme A carboxylase alpha (ACC), stearoyl-coenzyme A desaturase 1, 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR), and low-density lipoprotein receptor (LDLR). The ethanol-induced up-regulations of TNFalpha, LXRalpha, SREBP-1c, HMGR, and LDLR genes in the liver were reversed by feeding C. lanceolata root water extract for 8 weeks. Moreover, ethanol-induced decreases in the ratio of phospho-5'-AMP-activated protein kinase (AMPK) alpha/AMPKalpha and phospho-ACC/ACC protein levels in the liver were significantly restored (135% and 35% increases, respectively, P < .05) by supplementing them with C. lanceolata root water extract. In conclusion, C. lanceolata root water extract appears to be protective against alcoholic fatty liver through the regulation of SREBP-1c, LXRalpha, HMGR, and LDLR genes and by the phosphorylation of AMPKalpha and ACC, which are implicated in lipid metabolism.
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Affiliation(s)
- Keunsook Cho
- Department of Food and Nutrition, Brain Korea 21 Project, Yonsei University, Seoul, Republic of Korea
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18
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Kuehl PJ, Stratton SP, Powell MB, Myrdal PB. Preformulation, formulation, and in vivo efficacy of topically applied apomine. Int J Pharm 2009; 382:104-10. [PMID: 19699284 DOI: 10.1016/j.ijpharm.2009.08.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Revised: 08/06/2009] [Accepted: 08/13/2009] [Indexed: 11/26/2022]
Abstract
Apomine is a novel compound that inhibits the mevalonate/isoprenoid pathway of cholesterol synthesis and may prove effective as a skin cancer chemoprevention therapy. This research was focused on the development of a new delivery approach for chemoprevention of melanoma using topically delivered apomine. This included evaluating the effect of several factors on the stability of apomine in solution, utilizing these to develop a topical formulation, and conducting efficacy studies with the developed topical formulation in the TPras mouse model. Preformulation included the influence of pH, buffer species, ionic strength, and organic solvents on the stability of apomine at four different temperatures. Apomine was determined to undergo apparent first-order degradation kinetics for all conditions evaluated. Apomine undergoes base-catalyzed degradation. Less than 15% degradation is observed after >200 days under acidic conditions. Long-term stability studies were performed on two different topical cream formulations and indicate that both formulations are chemically stable for over 1 year at both 4 and 23 degrees C. The efficacy of topically applied apomine, from ethanol and developed 1% cream, was evaluated in vivo against the incidence of melanoma. Regardless of delivery vehicle apomine treatment caused a significant reduction in tumor incidence. Ethyl alcohol application of apomine resulted in a greater tumor incidence reduction when compared to the development cream formulation; however, this difference was not significant.
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Affiliation(s)
- Philip J Kuehl
- Lovelace Respiratory Research Institute, 2425 Ridgecrest Drive SE, Albuquerque, NM 87108, United States.
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19
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Nguyen AD, Lee SH, DeBose-Boyd RA. Insig-mediated, sterol-accelerated degradation of the membrane domain of hamster 3-hydroxy-3-methylglutaryl-coenzyme A reductase in insect cells. J Biol Chem 2009; 284:26778-88. [PMID: 19638338 DOI: 10.1074/jbc.m109.032342] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sterol-accelerated degradation of the enzyme 3-hydroxy-3-methylglutaryl-coenzyme A reductase is one of several mechanisms through which cholesterol synthesis is controlled in mammalian cells. This degradation results from sterol-induced binding of the membrane domain of reductase to endoplasmic reticulum membrane proteins called Insig-1 and Insig-2, which are carriers of a ubiquitin ligase called gp78. The ensuing gp78-mediated ubiquitination of reductase is a prerequisite for its rapid, 26 S proteasome-mediated degradation from endoplasmic reticulum membranes, a reaction that slows a rate-limiting step in cholesterol synthesis. Here, we report that the membrane domain of hamster reductase is subject to sterol-accelerated degradation in Drosophila S2 cells, but only when mammalian Insig-1 or Insig-2 are co-expressed. This degradation mimics the reaction that occurs in mammalian cells with regard to its absolute requirement for the action of Insigs, sensitivity to proteasome inhibition, augmentation by nonsterol isoprenoids, and sterol specificity. RNA interference studies reveal that this degradation requires the Drosophila Hrd1 ubiquitin ligase and several other proteins, including a putative substrate selector, which associate with the enzyme in yeast and mammalian systems. These studies define Insigs as the minimal requirement for sterol-accelerated degradation of the membrane domain of reductase in Drosophila S2 cells.
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Affiliation(s)
- Andrew D Nguyen
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9046, USA
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20
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21
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Edwards CM, Mueller G, Roelofs AJ, Chantry A, Perry M, Russell RGG, Van Camp B, Guyon-Gellin Y, Niesor EJ, Bentzen CL, Vanderkerken K, Croucher PI. Apomine, an inhibitor of HMG-CoA-reductase, promotes apoptosis of myeloma cells in vitro and is associated with a modulation of myeloma in vivo. Int J Cancer 2007; 120:1657-63. [PMID: 17230522 DOI: 10.1002/ijc.22478] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Apomine, a novel 1,1 bisphosphonate ester, increases the rate of degradation of HMG-CoA reductase, inhibiting the mevalonate pathway and thereby blocking cholesterol biosynthesis. We have investigated whether Apomine can induce myeloma cell apoptosis in vitro and modulate myeloma disease in vivo. Apomine induced a dose-dependent increase in apoptosis in NCI H929, RPMI 8226 and JJN-3 human myeloma cells. Apomine, unlike the bisphosphonate, alendronate, had no measurable effect on osteoclastic bone resorption in vitro. To investigate the effect of Apomine in vivo, 5T2MM murine myeloma cells were injected into C57BL/KaLwRij mice. After 8 weeks all animals had a serum paraprotein and were treated with Apomine (200 mg/kg), or vehicle, for 4 weeks. Animals injected with 5T2MM cells and treated with vehicle developed osteolytic bone lesions, reduced cancellous bone area, decreased bone mineral density (BMD) and increased osteoclast number. Apomine caused a decrease in serum paraprotein and a decrease in tumor burden. Apomine inhibited the development of osteolytic lesions and prevented the tumor-induced decreases in BMD. Apomine had no effect on osteoclast number in contrast to what had been seen previously with the bisphosphonate, zoledronic acid, suggesting that these are direct effects of Apomine on myeloma cells. This demonstrates that Apomine is able to promote myeloma cell apoptosis in vitro and inhibit the development of multiple myeloma and lytic bone disease in vivo. The use of bisphosphonate esters such as Apomine represents a novel therapeutic approach in the treatment of myeloma and, indirectly, the associated bone disease.
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Affiliation(s)
- Claire M Edwards
- Institute of Musculoskeletal Sciences and the Nuffield Department of Orthopaedic Surgery, University of Oxford, Nuffield Orthopaedic Center, Oxford, United Kingdom
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22
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Roelofs AJ, Edwards CM, Russell RGG, Ebetino FH, Rogers MJ, Hulley PA. Apomine enhances the antitumor effects of lovastatin on myeloma cells by down-regulating 3-hydroxy-3-methylglutaryl-coenzyme A reductase. J Pharmacol Exp Ther 2007; 322:228-35. [PMID: 17412884 PMCID: PMC2820734 DOI: 10.1124/jpet.106.116467] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Apomine, a 1,1-bisphosphonate-ester with antitumor activity, has previously been reported to strongly down-regulate 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase), the rate-limiting enzyme in the mevalonate pathway responsible for the prenylation of proteins. Here, we show that although apomine down-regulated HMG-CoA reductase protein levels in myeloma cells, it did not inhibit protein prenylation, and apomine-induced apoptosis could not be prevented by mevalonate, indicating that apomine cytotoxicity is independent from its effects on HMG-CoA reductase. Instead, apomine cytotoxicity was prevented by the addition of phosphatidylcholine, which is similar to the previously reported ability of phosphatidylcholine to overcome the cytotoxicity of farnesol, whereas phosphatidylcholine had no effect on down-regulation of HMG-CoA reductase by apomine. These findings raised the possibility that apomine, independent from its own cytotoxic effects, could enhance the antitumor effects of the competitive HMG-CoA reductase inhibitor lovastatin via down-regulating HMG-CoA reductase. Indeed, treatment with apomine in combination with lovastatin resulted in synergistic decreases in viable cell number and induction of apoptosis. At the concentrations used, apomine down-regulated HMG-CoA reductase protein levels without being cytotoxic. Accumulation of unprenylated Rap1A by lovastatin was enhanced in the presence of apomine. Furthermore, synergy was completely prevented by mevalonate, and apomine did not synergize with desoxolovastatin, which does not inhibit HMG-CoA reductase. We conclude that the synergistic drug interaction results from an enhancement by apomine of the effects of lovastatin, mediated by down-regulation of HMG-CoA reductase by apomine. Thus, these findings demonstrate a novel strategy for enhancing the antitumor effects of lovastatin.
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Affiliation(s)
- Anke J Roelofs
- Bone Research Group, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK.
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23
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Abstract
HMG-CoA reductase inhibitors (statins) reduce cardiovascular disease morbidity and mortality with a high level of safety. Nonetheless, there are substantial numbers of people who either do not tolerate statins or whose low-density lipoprotein (LDL) levels are not lowered adequately. For these reasons, there is a need to develop other cholesterol-lowering drugs. A target for these new agents is provided by the enzymes distal to HMG-CoA reductase in the cholesterol biosynthesis pathway. Two classes of drugs have been developed: (i) squalene synthase inhibitors, which act at the first committed step in cholesterol biosynthesis, distal to the mevalonate-farnesyl diphosphate pathway; and (ii) oxidosqualene cyclase inhibitors, which act distal to the squalene intermediate. Of these, squalene synthase inhibitors have received more attention and are the subject of this review. Squalene synthase inhibitors decrease circulating LDL-cholesterol by the induction of hepatic LDL receptors in a similar manner to statins. They have fewer secondary effects mediated by a decrease in non-cholesterol products of mevalonate metabolism distal to HMG-CoA reductase, but have the potential to increase intermediates proximal to squalene. Squalene synthase inhibitors are just now entering clinical trials and data on how effectively they lower LDL-cholesterol and how they compliment the actions of statins and other agents is awaited with considerable interest.
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Affiliation(s)
- Valentine Charlton-Menys
- Division of Cardiovascular and Endocrine Sciences, Cardiovascular Research Group, Core Technology Facility, University of Manchester, Manchester, UK.
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Pourpak A, Dorr RT, Meyers RO, Powell MB, Stratton SP. Cytotoxic activity of Apomine is due to a novel membrane-mediated cytolytic mechanism independent of apoptosis in the A375 human melanoma cell line. Invest New Drugs 2006; 25:107-14. [PMID: 17024575 DOI: 10.1007/s10637-006-9015-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2006] [Accepted: 09/14/2006] [Indexed: 10/24/2022]
Abstract
Apomine, a novel bisphosphonate ester, has demonstrated anticancer activity in a variety of cancer cell lines; however, its mechanism of cytotoxicity is not well understood. Previous work has demonstrated that Apomine induces cell death by activation of caspase-3 in several cancer cell types. However, we have demonstrated that Apomine induces cell death in the A375 human melanoma cell line through a novel membrane-mediated mechanism that is independent of caspase-3 activation. This mechanism of membrane lysis may apply to other bisphosphonates and may be an important mechanism for overcoming resistance to apoptosis. Interestingly, Apomine-mediated cell death in the A375 and UACC 3093 human melanoma cell lines is also independent of N-Ras farnesylation, which was a previously described mechanism of action for Apomine in other cancer cell types. These data suggest that Apomine induces cell death through a novel plasma membrane-mediated cytolytic pathway, independent of caspase-3 activation and N-Ras farnesylation.
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Affiliation(s)
- Alan Pourpak
- Arizona Cancer Center, The University of Arizona, 1515 N, Campbell Avenue, Tucson, AZ 85724, USA
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Kuehl PJ, Angersbach BS, Stratton SP, Myrdal PB. Development of an HPLC method for the analysis of Apomine in a topical cream formulation. J Pharm Biomed Anal 2006; 40:975-80. [PMID: 16181759 DOI: 10.1016/j.jpba.2005.07.046] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2005] [Revised: 07/21/2005] [Accepted: 07/25/2005] [Indexed: 11/17/2022]
Abstract
A stability indicating, reversed-phase high performance liquid chromatographic method was developed for the quantification of Apomine, tetraisopropyl 2-(3,5-di-tert-butyl-4-hydroxyphenyl)-ethyl-1, 1-bisphosphonate, in a topical cream formulation. Analysis of Apomine in the cream formulation was performed through a dilution of the cream base with tetrahydrofuran. This allowed the current method to bypass extraction and/or centrifugation for direct injection and analysis. Separation was achieved using an Alltima C18 5 microm, 150 mm x 2.1 mm column and employed a gradient procedure, beginning with acetonitrile-water (65:35, v/v), at 0.6 mL/min for 9 min, followed by a rinse with isopropyl alcohol for 9 min. The complete gradient method has been optimized to separate Apomine from the nonpolar cream components, wash and equilibrate the column in a 30-min assay. This report demonstrates that this method is effective for quantification of Apomine in a cream formulation.
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Affiliation(s)
- Philip J Kuehl
- College of Pharmacy, University of Arizona, 1703 E. Mabel St., Tucson, AZ 85721, USA.
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26
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Pellicciari R, Costantino G, Fiorucci S. Farnesoid X receptor: from structure to potential clinical applications. J Med Chem 2005; 48:5383-403. [PMID: 16107136 DOI: 10.1021/jm0582221] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Roberto Pellicciari
- Dipartimento di Chimica e Tecnologia del Farmaco, Università di Perugia, Via del Liceo 1, I-06123 Perugia, Italy.
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Bonate PL, Floret S, Bentzen C. Population pharmacokinetics of APOMINE: a meta-analysis in cancer patients and healthy males. Br J Clin Pharmacol 2004; 58:142-55. [PMID: 15255796 PMCID: PMC1884594 DOI: 10.1111/j.1365-2125.2004.02111.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
AIMS 1) To characterize the population pharmacokinetics of apomine in healthy males and in male and female patients with solid tumours and 2) to understand more fully the influence of induction and between- and within-subject variability on exposure to drug using Monte Carlo simulation. METHODS Apomine was administered once- or twice-daily with or without food in single and multiple oral doses of 30-2100 mg to healthy males (n = 19) and patients with solid tumours (n = 19). The data were divided into model development and validation sets. Models were developed using standard population methods. These were the identification of an appropriate base model, calculation of the empirical Bayes estimates of the primary pharmacokinetic parameters, covariate screening, forward stepwise addition of covariates using the likelihood ratio test as a model selection criteria, and backwards elimination to obtain the final model. To study the influence of data from individual subjects, the model development dataset was subjected to the delete-1 jack-knife and the final model was fitted to each jack-knifed dataset. Principal components analysis of the jack-knifed matrix of model parameters identified two influential subjects who were removed from the dataset, and the final model contained data from the remaining subjects. Model validation was examined using goodness of fit statistics and relative error measures using independent datasets from cancer patients. The model provided a reasonable approximation to the pharmacokinetic measurements in the validation datasets. Computer simulations were undertaken to understand further the pharmacokinetics of apomine in otherwise healthy females, a population not yet studied. RESULTS Apomine pharmacokinetics were complex and consistent with a two-compartment model with a lag-time. Apparent oral clearance at baseline and apparent volume of distribution at steady-state were larger in healthy males than in cancer patients (41 ml h(-1) and 14.1 l vs 10 ml h(-1) and 8.9 l, respectively, for a 75 kg person). Clearance was time-variant showing a maximal increase with full induction of 320 ml h(-1), independent of patient type. The time to reach 50% maximal induction was about 2 days. The fraction of drug absorbed was relatively constant at doses less than 100-200 mg once daily but decreased at higher doses. Food also decreased relative bioavailability by 36%. Patient characteristics had no effect on apomine pharmacokinetics except for weight, which was proportional to the volume of the central compartment. Between-subject variability (68% for clearance, 30% for central volume, and 141% for peripheral volume) was moderate to large and independent of patient type. Inter-occasion variability was small (18% for both clearance and central volume). Residual variability was modelled with an additive and proportional error model. Cancer patients had slightly higher plasma concentrations than healthy males but this difference was probably not clinically significant. Steady-state was reached in about 3-4 days after once-daily drug administration. The half-life of apomine after three weeks of once-daily dosing was 41 h in cancer patients and 32 h in healthy males. CONCLUSIONS A population model for apomine has been developed has been developed that characterizes its pharmacokinetics in cancer patients and healthy subjects under a variety of conditions.
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Affiliation(s)
- Peter L Bonate
- ILEX Products, 4545 Horizon Hill Blvd, San Antonio, TX 78229, USA.
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28
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Sever N, Lee PCW, Song BL, Rawson RB, Debose-Boyd RA. Isolation of Mutant Cells Lacking Insig-1 through Selection with SR-12813, an Agent That Stimulates Degradation of 3-Hydroxy-3-methylglutaryl-Coenzyme A Reductase. J Biol Chem 2004; 279:43136-47. [PMID: 15247248 DOI: 10.1074/jbc.m406406200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Insig-1 and Insig-2 are membrane proteins of the endoplasmic reticulum that regulate lipid metabolism by the following two actions: 1) sterol-induced binding to 3-hydroxy-3-methylglutaryl-coenzyme A reductase, an action that leads to ubiquitination and degradation of the enzyme; and 2) sterol-induced binding to SREBP cleavage-activating protein, an action that blocks the proteolytic processing of sterol regulatory element-binding proteins (SREBPs), membrane-bound transcription factors that enhance the synthesis of cholesterol and fatty acids. Here we report the isolation of a new mutant line of Chinese hamster ovary cells, designated SRD-14, in which Insig-1 mRNA and protein are not produced due to a partial deletion of the INSIG-1 gene. The SRD-14 cells were produced by gamma-irradiation, followed by selection with the 1,1-bisphosphonate ester SR-12813, which mimics sterols in accelerating reductase degradation but does not block SREBP processing. SRD-14 cells fail to respond to sterols by promoting reductase ubiquitination and degradation. The rate at which sterols suppress SREBP processing is significantly slower in SRD-14 cells than wild type CHO-7 cells. Sterol regulation of reductase degradation and SREBP processing is restored when SRD-14 cells are transfected with expression plasmids encoding either Insig-1 or Insig-2. These results provide formal genetic proof for the essential role of Insig-1 in feedback control of lipid synthesis in cultured cells.
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Affiliation(s)
- Navdar Sever
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9046, USA
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