51
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Hong SH, Kim J, Kim JM, Lee SY, Shin DS, Son KH, Han DC, Sung YK, Kwon BM. Apoptosis induction of 2′-hydroxycinnamaldehyde as a proteasome inhibitor is associated with ER stress and mitochondrial perturbation in cancer cells. Biochem Pharmacol 2007; 74:557-65. [PMID: 17606223 DOI: 10.1016/j.bcp.2007.05.016] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Revised: 05/18/2007] [Accepted: 05/21/2007] [Indexed: 11/27/2022]
Abstract
2'-Hydroxycinnamaldehyde (HCA), isolated from the stem bark of Cinnamomum cassia, and 2'-benzoyloxycinnamaldehyde (BCA), one of HCA derivatives, have antiproliferative activities on several human cancer cell lines. Our previous study suggested that reactive oxygen species (ROS) and caspase-3 are the major regulators of HCA-induced apoptosis. In the present study, we demonstrated a novel molecular target using in vitro pull-down assay by biotin-labeled HCA (biotin-HCA) in SW620 cells. We analyzed 11 differential spots of 2-dimensional gel prepared with pull-downed proteins by biotin-HCA. Among them, five spots were identified as proteasome subunits. An in vitro 26S proteasome function assay using specific fluorogenic substrates showed that HCA potently inhibits L3-like activity of the proteasome. In addition, HCA showed inhibitory action against chymotrypsin-like, trypsin-like, and PGPH-like activities. DNA microarray showed that HCA induced heat shock family and ER stress-responsive genes, which reflects the accumulation of misfolded proteins by proteasome inhibition. On western blot analysis, it was confirmed that HCA induces glucose-regulated protein, 78 kDa (GRP78) and some representative endoplasmic reticulum (ER) stress-responsive proteins. Furthermore, HCA treatment decreased mitochondrial membrane potential. The effect of HCA on cytochrome c and Bax translocation between cytosol and mitochondrial membrane was clarified using western blot analysis. These results suggest that HCA-induced apoptosis is associated with the inhibition of the proteasome activity that leads in turn to the increase of ER stress and mitochondrial perturbation.
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Affiliation(s)
- Su Hyung Hong
- Department of Dental Microbiology, School of Dentistry, Kyungpook National University, Daegu 700-412, Republic of Korea
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52
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Borissenko L, Groll M. 20S proteasome and its inhibitors: crystallographic knowledge for drug development. Chem Rev 2007; 107:687-717. [PMID: 17316053 DOI: 10.1021/cr0502504] [Citation(s) in RCA: 332] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Ljudmila Borissenko
- Charité (CCM), Institut für Biochemie, AG Strukturforschung, Monbijoustrasse 2, 10117 Berlin, Germany
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53
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Howell GJ, Holloway ZG, Cobbold C, Monaco AP, Ponnambalam S. Cell biology of membrane trafficking in human disease. ACTA ACUST UNITED AC 2007; 252:1-69. [PMID: 16984815 PMCID: PMC7112332 DOI: 10.1016/s0074-7696(06)52005-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Understanding the molecular and cellular mechanisms underlying membrane traffic pathways is crucial to the treatment and cure of human disease. Various human diseases caused by changes in cellular homeostasis arise through a single gene mutation(s) resulting in compromised membrane trafficking. Many pathogenic agents such as viruses, bacteria, or parasites have evolved mechanisms to subvert the host cell response to infection, or have hijacked cellular mechanisms to proliferate and ensure pathogen survival. Understanding the consequence of genetic mutations or pathogenic infection on membrane traffic has also enabled greater understanding of the interactions between organisms and the surrounding environment. This review focuses on human genetic defects and molecular mechanisms that underlie eukaryote exocytosis and endocytosis and current and future prospects for alleviation of a variety of human diseases.
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Affiliation(s)
- Gareth J Howell
- Endothelial Cell Biology Unit, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
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54
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Fu Y, Xu B, Zou X, Ma C, Yang X, Mou K, Fu G, Lü Y, Xu P. Design and synthesis of a novel class of furan-based molecules as potential 20S proteasome inhibitors. Bioorg Med Chem Lett 2007; 17:1102-6. [PMID: 17134894 DOI: 10.1016/j.bmcl.2006.11.020] [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] [Received: 06/23/2006] [Revised: 10/11/2006] [Accepted: 11/07/2006] [Indexed: 10/23/2022]
Abstract
A novel class of furan-based compounds as potential 20S proteasome inhibitors have been designed and synthesized, among which nine compounds are peptide derivatives and six molecules are statine peptidomimetics. The C-terminal furanyl moiety was introduced to target molecules as furan-based amino acids. All the compounds were obtained steadily with moderate to high yield. Compound 12 was a selective moderate potent proteasome peptidomimetic inhibitor. It inhibited HepG2 and HL-60 proliferation effectively.
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Affiliation(s)
- Yiqiu Fu
- Department of Medicinal Chemistry, State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100083, PR China
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55
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Caravita T, de Fabritiis P, Palumbo A, Amadori S, Boccadoro M. Bortezomib: efficacy comparisons in solid tumors and hematologic malignancies. ACTA ACUST UNITED AC 2006; 3:374-87. [PMID: 16826218 DOI: 10.1038/ncponc0555] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2005] [Accepted: 04/04/2006] [Indexed: 12/20/2022]
Abstract
Proteasome inhibition represents a new anticancer approach, with the potential effect of arresting tumor growth, metastasis and angiogenesis through the activation of multiple mechanisms. Bortezomib is a biologically active agent, producing predictable, dose-related and reversible proteasome inhibition; it has shown antitumor activity in various malignancies and is the first proteasome inhibitor to be used in clinical practice. Several trials demonstrated that bortezomib is relatively well tolerated, causing manageable nonhematologic and hematologic toxicity. The drug was approved in 2003 by the FDA for the treatment of patients with multiple myeloma who had received at least two prior therapies and demonstrated disease progression on the last therapy; its application was expanded recently for second-line treatment. This article summarizes the principal clinical trials of bortezomib and discusses its efficacy in solid and hematologic tumors.
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Affiliation(s)
- Tommaso Caravita
- Myeloma Unit, Hematology Department, St Eugenio Hospital, Rome, Italy.
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56
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Ying WZ, Zhang HG, Sanders PW. EGF receptor activity modulates apoptosis induced by inhibition of the proteasome of vascular smooth muscle cells. J Am Soc Nephrol 2006; 18:131-42. [PMID: 17151333 DOI: 10.1681/asn.2006040333] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The observation that intracellular protein turnover rates participate directly in cell viability led to the development and clinical use of potent proteasome inhibitors. This study determined that the mechanism of apoptosis that is induced by inhibition of the proteasome of vascular smooth muscle cells (VSMC) was related to the intracellular accumulation of Bad, a BH3-only member of the Bcl-2 family of apoptosis regulators. Experiments confirmed that the apoptotic process was mitochondria- and caspase-dependent. Ubiquitination and accumulation of Bad in VSMC followed inhibition of the proteasome, and depletion of Bad using RNA interference prevented apoptosis that was induced by proteasome inhibition with PS-341. EGF receptor (EGFR) activation produced posttranslational modifications of Bad, providing the pro-survival signals that prevented apoptosis of smooth muscle cells during proteasome inhibition. Antagonists of the EGFR potentiated the apoptotic rate. In summary, the activities of the EGFR and the proteasome focused on Bad and the intrinsic apoptotic pathway and were involved integrally in determining viability of VSMC. These findings might prove useful in the management of diseases in which proliferation of vascular smooth muscle cells plays a central role.
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MESH Headings
- Animals
- Apoptosis/drug effects
- Apoptosis/physiology
- Boronic Acids/pharmacology
- Bortezomib
- Caspases/metabolism
- Cell Proliferation
- Cells, Cultured
- ErbB Receptors/antagonists & inhibitors
- ErbB Receptors/metabolism
- Mitochondria/metabolism
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/cytology
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Protease Inhibitors/pharmacology
- Proteasome Inhibitors
- Protein Processing, Post-Translational
- Pyrazines/pharmacology
- Quinazolines/pharmacology
- RNA Interference
- Rats
- bcl-Associated Death Protein/antagonists & inhibitors
- bcl-Associated Death Protein/genetics
- bcl-Associated Death Protein/metabolism
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Affiliation(s)
- Wei-Zhong Ying
- Division of Nephrology/Department of Medicine, niversity of Alabama at Birmingham, Birmingham, AL 35294-0007, USA
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57
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Hol EM, Fischer DF, Ovaa H, Scheper W. Ubiquitin proteasome system as a pharmacological target in neurodegeneration. Expert Rev Neurother 2006; 6:1337-47. [PMID: 17009921 DOI: 10.1586/14737175.6.9.1337] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Ubiquitinated protein aggregates are observed in the brains of Alzheimer's, Parkinson's and Huntington's disease patients and in other neurodegenerative disorders. These aggregates indicate that the ubiquitin proteasome system may be impaired in these diseases. To date no therapy is available that specifically targets this system, although preventing aggregate formation or stimulating the degradation of already formed aggregates by targeting components of the ubiquitin proteasome system is an attractive therapeutic approach. Here, we review the role of the ubiquitin proteasome system in aggregate formation with respect to neurodegenerative diseases, discussing the unfolded protein response, endoplasmic reticulum-associated degradation, aggresome formation and accumulation as well as aggregation and neurotoxicity of proteins involved in neurodegeneration. The potential of pharmacological intervention within this system in patients suffering from neurodegenerative diseases will be evaluated.
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Affiliation(s)
- Elly M Hol
- Netherlands Institute for Neuroscience, Research Group Cellular Quality Control, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands.
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58
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Legnani FG, Pradilla G, Thai QA, Fiorindi A, Recinos PF, Tyler BM, Gaini SM, DiMeco F, Brem H, Olivi A. Lactacystin exhibits potent anti-tumor activity in an animal model of malignant glioma when administered via controlled-release polymers. J Neurooncol 2006; 77:225-32. [PMID: 16609837 PMCID: PMC1635004 DOI: 10.1007/s11060-005-6937-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Lactacystin, a proteasome-inhibitor, has been shown to induce apoptosis of experimental gliomas in vitro. However, its systemic toxicity prevents further clinical use. To circumvent this problem, lactacystin can be delivered intratumorally. We tested the efficacy of lactacystin incorporated into controlled-release polymers for treating experimental gliomas. 9L-gliosarcoma and F98-glioma cell lines were treated with lactacystin (10-100 microg/ml) for 72 h in vitro. Cell-viability was measured with MTT-assays. Toxicity of lactacystin/polycarboxyphenoxypropane-sebacic-acid (pCPP : SA) polymers was tested in vivo using Fischer-344 rats intracranially implanted with lactacystin polymers loaded from 0.1 to 2% lactacystin by weight. The efficacy of 1, 1.3, 1.5 and 1.7% lactacystin/pCPP : SA polymers was determined in Fischer-344 rats intracranially challenged with 9L and treated either simultaneously or 5 days after tumor implantation. Lactacystin was cytotoxic in 9L cells, causing a 16 +/- 8% growth inhibition at 10-microg/ml that increased to 78 +/- 4% at 100-microg/ml. Similarly, lactacystin inhibited growth of F98 by 18 +/- 8% at 10-microg/ml and 74 +/- 2% at 100-microg/ml in vitro. Polymers released lactacystin for 21 days and intracranial implantation in rats neither generate local nor systemic toxicity at doses lower than 2%. Treatment with lactacystin/pCPP : SA polymers with loading concentrations of 1.0, 1.3, and 1.5% prolonged survival of animals intracranially challenged with 9L when polymers where inserted in the day of tumor implantation. In conclusion, lactacystin exhibits potent cytotoxic-activity against 9L and F98 in vitro, it can be efficiently incorporated and delivered using controlled-release polymers, and at the proposed concentrations lactacystin polymers are safe for CNS delivery and prolong survival in the 9L model.
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Affiliation(s)
- Federico G. Legnani
- Department of Neurosurgery and Oncology Johns Hopkins University, School of Medicine
- Department of Neurosurgery University of Milan, School of Medicine Italy
| | - Gustavo Pradilla
- Department of Neurosurgery and Oncology Johns Hopkins University, School of Medicine
| | - Quoc-Anh Thai
- Department of Neurosurgery and Oncology Johns Hopkins University, School of Medicine
| | | | - Pablo F. Recinos
- Department of Neurosurgery and Oncology Johns Hopkins University, School of Medicine
| | - Betty M. Tyler
- Department of Neurosurgery and Oncology Johns Hopkins University, School of Medicine
| | - Sergio M. Gaini
- Department of Neurosurgery University of Milan, School of Medicine Italy
| | - Francesco DiMeco
- Department of Neurosurgery and Oncology Johns Hopkins University, School of Medicine
- Istituto Nazionale Neurologico “Carlo Besta”, Milan, Italy
| | - Henry Brem
- Department of Neurosurgery and Oncology Johns Hopkins University, School of Medicine
- Department of Neurosurgery and Oncology, Johns Hopkins University, School of Medicine
| | - Alessandro Olivi
- Department of Neurosurgery and Oncology Johns Hopkins University, School of Medicine
- Department of Neurosurgery and Oncology, Johns Hopkins University, School of Medicine
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59
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Montagut C, Rovira A, Albanell J. The proteasome: a novel target for anticancer therapy. Clin Transl Oncol 2006; 8:313-7. [PMID: 16760005 DOI: 10.1007/s12094-006-0176-8] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The proteasome is an ubiquituous enzyme complex that plays a critical role in the degradation of many proteins involved in cell cycle regulation, apoptosis and angiogenesis. Since these pathways are fundamental for cell survival and proliferation, particularly in cancer cells, the inhibition of proteasome is an attractive potential anticancer therapy. Bortezomib (Velcade, formerly PS-341) is an extremely potent and selective proteasome inhibitor that shows strong activity in in vitro and in vivo laboratory studies against many solid and hematologic tumor types. Moreover, bortezomib, mainly by inhibition of the NF-kappaB pathway, has a chemosensitizing effect when administered together with other antitumoral drugs. Clinical phase I trials, showed good tolerance of bortezomib at doses that achieved a desired degree of proteasome inhibition. Phase II studies showed high response rates in refractory multiple myeloma patients, which led to the accelerated approval of bortezomib by the Food and Drug Administration (FDA) and the European Medicines Agency (EMEA) for this indication. A phase III trial comparing bortezomib to dexamethasone in refractory/relapsed multiple myeloma patients had to be halted due to a survival advantage in the bortezomib arm. Additional studies are focusing in the potential benefit of bortezomib in newly diagnosed multiple myeloma patients. In other solid and hematological malignancies, phase II studies with bortezomib alone or in combination are ongoing with encouraging results, particularly in lung cancer and lymphoma.
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Affiliation(s)
- C Montagut
- Medical Oncology Department & Experimental Cancer Therapeutics Unit, URTEC, Hospital del Mar, Barcelona, Spain
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60
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Dikshit P, Chatterjee M, Goswami A, Mishra A, Jana NR. Aspirin induces apoptosis through the inhibition of proteasome function. J Biol Chem 2006; 281:29228-35. [PMID: 16880202 DOI: 10.1074/jbc.m602629200] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Aspirin and other nonsteroidal anti-inflammatory drugs inhibit cell proliferation and induce apoptosis in various cancer cell lines, which is considered to be an important mechanism for their anti-tumor activity and prevention of carcinogenesis. However, the molecular mechanisms through which these compounds induce apoptosis are not well understood. Here we have found that aspirin treatment of the mouse Neuro 2a cells impaired the proteasome function and caused severe mitochondrial abnormalities. Treatment with aspirin lead to a dose- and time-dependent decrease in proteasome activity and an increase in the accumulation of ubiquitylated proteins in the cells, which correlated with its effect on cell death. Aspirin exposure also resulted in an increase in the half-life of pd1EGFP, a model substrate of proteasome, as well as various intracellular substrates like Bax, IkappaB-alpha, p53, and p27(kip1). Aspirin-induced proteasomal malfunction might be responsible, at least in part, for the down-regulation of NF-kappaB activity and neurite outgrowth. Finally, we have shown that aspirin treatment caused changes in the mitochondrial membrane potential, release of cytochrome c from mitochondria, and activation of caspase-9 and -3, which could be because of the proteasomal dysfunction.
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Affiliation(s)
- Priyanka Dikshit
- Cellular and Molecular Neuroscience Laboratory, National Brain Research Centre, Manesar, Gurgaon 122050, India
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61
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Dikshit P, Goswami A, Mishra A, Chatterjee M, Jana NR. Curcumin induces stress response, neurite outgrowth and prevent NF-kappaB activation by inhibiting the proteasome function. Neurotox Res 2006; 9:29-37. [PMID: 16464750 DOI: 10.1007/bf03033305] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Curcumin, a natural polyphenolic compound, has long been known as an anti-tumour and anti-inflammatory compound; although, the common mechanism through which it exhibits such properties are remains unclear. Recently, we reported that the curcumin-induced apoptosis is mediated through the impairment of ubiquitin proteasome system (UPS). Here, we show that curcumin disrupts UPS function by directly inhibiting the enzyme activity of the proteasome's 20S core catalytic component. Like other proteasome inhibitors, curcumin exposure induces neurite outgrowth and the stress response, as evident from the induction of various cytosolic and endoplasmic reticulum chaperones as well as induction of transcription factor CHOP/GADD153. The direct inhibition of proteasome activity also causes an increase in half-life of IkappaB-alpha that ultimately leads to the down-regulation of NF-kappaB activation. These results suggest that curcumin-induced proteasomal malfunction might be linked with both anti-proliferative and anti-inflammatory activities.
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Affiliation(s)
- Priyanka Dikshit
- Cellular and Molecular Neuroscience Laboratory, National Brain Research Centre, Manesar, Gurgaon - 122 050, India
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62
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Bazzaro M, Lee MK, Zoso A, Stirling WLH, Santillan A, Shih IM, Roden RBS. Ubiquitin-Proteasome System Stress Sensitizes Ovarian Cancer to Proteasome Inhibitor–Induced Apoptosis. Cancer Res 2006; 66:3754-63. [PMID: 16585202 DOI: 10.1158/0008-5472.can-05-2321] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The ubiquitin-proteasome system (UPS) mediates targeted protein degradation. Notably, the UPS determines levels of key checkpoint proteins controlling apoptosis and proliferation by controlling protein half-life. Herein, we show that ovarian carcinoma manifests an overstressed UPS by comparison with normal tissues by accumulation of ubiquitinated proteins despite elevated proteasome levels. Elevated levels of total ubiquitinated proteins and 19S and 20S proteasome subunits are evident in both low-grade and high-grade ovarian carcinoma tissues relative to benign ovarian tumors and in ovarian carcinoma cell lines relative to immortalized surface epithelium. We find that ovarian carcinoma cell lines exhibit greater sensitivity to apoptosis in response to proteasome inhibitors than immortalized ovarian surface epithelial cells. This sensitivity correlates with increased cellular proliferation rate and UPS stress rather than absolute proteasome levels. Proteasomal inhibition in vitro induces cell cycle arrest and the accumulation of p21 and p27 and triggers apoptosis via activation of caspase-3. Furthermore, treatment with the licensed proteasome inhibitor PS-341 slows the growth of ES-2 ovarian carcinoma xenograft in immunodeficient mice. In sum, elevated proliferation and metabolic rate resulting from malignant transformation of the epithelium stresses the UPS and renders ovarian carcinoma more sensitive to apoptosis in response to proteasomal inhibition.
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Affiliation(s)
- Martina Bazzaro
- Department of Pathology, The Johns Hopkins School of Medicine, Cancer Research Building 2, 1550 Orleans Street, Baltimore, MD 21231, USA
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63
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Roccaro AM, Hideshima T, Raje N, Kumar S, Ishitsuka K, Yasui H, Shiraishi N, Ribatti D, Nico B, Vacca A, Dammacco F, Richardson PG, Anderson KC. Bortezomib mediates antiangiogenesis in multiple myeloma via direct and indirect effects on endothelial cells. Cancer Res 2006; 66:184-91. [PMID: 16397231 DOI: 10.1158/0008-5472.can-05-1195] [Citation(s) in RCA: 211] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Bone marrow angiogenesis plays an important role in the pathogenesis and progression in multiple myeloma. Recent studies have shown that proteasome inhibitor bortezomib (Velcade, formerly PS-341) can overcome conventional drug resistance in vitro and in vivo; however, its antiangiogenic activity in the bone marrow milieu has not yet been defined. In the present study, we examined the effects of bortezomib on the angiogenic phenotype of multiple myeloma patient-derived endothelial cells (MMEC). At clinically achievable concentrations, bortezomib inhibited the proliferation of MMECs and human umbilical vein endothelial cells in a dose-dependent and time-dependent manner. In functional assays of angiogenesis, including chemotaxis, adhesion to fibronectin, capillary formation on Matrigel, and chick embryo chorioallantoic membrane assay, bortezomib induced a dose-dependent inhibition of angiogenesis. Importantly, binding of MM.1S cells to MMECs triggered multiple myeloma cell proliferation, which was also abrogated by bortezomib in a dose-dependent fashion. Bortezomib triggered a dose-dependent inhibition of vascular endothelial growth factor (VEGF) and interleukin-6 (IL-6) secretion by the MMECs, and reverse transcriptase-PCR confirmed drug-related down-regulation of VEGF, IL-6, insulin-like growth factor-I, Angiopoietin 1 (Ang1), and Ang2 transcription. These data, therefore, delineate the mechanisms of the antiangiogenic effects of bortezomib on multiple myeloma cells in the bone marrow milieu.
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Affiliation(s)
- Aldo Maria Roccaro
- Jerome Lipper Multiple Myeloma Center, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts 02115, USA
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64
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Mitsiades CS, Mitsiades N, Hideshima T, Richardson PG, Anderson KC. Proteasome inhibition as a therapeutic strategy for hematologic malignancies. Expert Rev Anticancer Ther 2006; 5:465-76. [PMID: 16001954 DOI: 10.1586/14737140.5.3.465] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The ubiquitin-proteasome pathway is a principal intracellular mechanism for controlled protein degradation and has recently emerged as an attractive target for anticancer therapies since several cell cycle regulators and modulators of apoptosis are degraded through this pathway. The current state of the field of proteasome inhibitors and their prototypic member, bortezomib, which was recently approved by the US Food and Drug Administration for the treatment of advanced multiple myeloma, is reviewed. Particular emphasis is placed on the preclinical research data that became the basis for eventual clinical applications of proteasome inhibitors, an overview of the clinical development of this exciting drug class in multiple myeloma, and an appraisal of possible uses in other hematologic malignancies, such as non-Hodgkin's lymphomas.
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Affiliation(s)
- Constantine S Mitsiades
- Jerome Lipper Multiple Myeloma Center, Department of Medical Oncology, Dana Farber Cancer Institute, Harvard Medical School, 44 Binney Street, Boston, MA, USA.
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65
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Tsukamoto O, Minamino T, Okada KI, Shintani Y, Takashima S, Kato H, Liao Y, Okazaki H, Asai M, Hirata A, Fujita M, Asano Y, Yamazaki S, Asanuma H, Hori M, Kitakaze M. Depression of proteasome activities during the progression of cardiac dysfunction in pressure-overloaded heart of mice. Biochem Biophys Res Commun 2005; 340:1125-33. [PMID: 16403436 DOI: 10.1016/j.bbrc.2005.12.120] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2005] [Accepted: 12/15/2005] [Indexed: 12/19/2022]
Abstract
The ubiquitin-proteasome system contributes to regulation of apoptosis degrading apoptosis-regulatory proteins. Marked accumulation of ubiquitinated proteins in cardiomyocytes of human failing hearts suggested impaired ubiquitin-proteasome system in heart failure. Since cardiomyocyte apoptosis contributes to the progression of cardiac dysfunction in pressure-overloaded hearts, we investigated the role of ubiquitin-proteasome system in such conditions. We found that proteasome activities already depressed before the onset of cardiac dysfunction in pressure-overloaded hearts of mice. Cardiomyocyte apoptosis was observed along with depression of proteasome activities and elevation of proapoptotic/antiapoptotic protein ratio in failing hearts. In cultured cardiomyocytes, pharmacological inhibition of proteasome accumulated proapoptotic proteins such as p53 and Bax. Gene silencing of these proapoptotic proteins by RNA interference prevented the accumulation of respective proteins and attenuated cardiomyocyte apoptosis induced by proteasome inhibition. We conclude that depression of proteasome activities contributes to cardiac dysfunction resulting from cardiomyocyte apoptosis through accumulation of proapoptotic proteins by impaired degradation.
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Affiliation(s)
- Osamu Tsukamoto
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
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66
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Chauhan D, Hideshima T, Mitsiades C, Richardson P, Anderson KC. Proteasome inhibitor therapy in multiple myeloma. Mol Cancer Ther 2005; 4:686-92. [PMID: 15827343 DOI: 10.1158/1535-7163.mct-04-0338] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Multiple myeloma remains incurable despite available therapies, and novel therapies that target both tumor cell and bone marrow microenvironment are urgently needed. Preclinical in vitro and in vivo studies show remarkable anti-multiple myeloma activity of the proteasome inhibitor bortezomib/PS-341 even in multiple myeloma cells refractory to multiple prior therapies, including dexamethasone, melphalan, and thalidomide. Based on these findings, the U.S. Food and Drug Administration recently approved the first proteasome inhibitor bortezomib (Velcade), formerly known as PS-341, for the treatment of relapsed/refractory multiple myeloma. Bortezomib therapy has set an outstanding example of translational research in the field of oncology. Genomics and proteomic studies further provide rationale for combining bortezomib with conventional and novel agents to inhibit multiple myeloma growth, overcome drug resistance, reduce attendant toxicity, and improve patient outcome in multiple myeloma.
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Affiliation(s)
- Dharminder Chauhan
- The Jerome Lipper Multiple Myeloma Center, Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, 44 Binney Street, Boston, Massachusetts 02115, USA
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67
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Abstract
The ubiquitin–proteasome pathway is a principle intracellular mechanism for controlled protein degradation and has recently emerged as an attractive target for anticancer therapies, because of the pleiotropic cell-cycle regulators and modulators of apoptosis that are controlled by proteasome function. In this chapter, we review the current state of the field of proteasome inhibitors and their prototypic member, bortezomib, which was recently approved by the U.S. Food and Drug Administration for the treatment of advanced multiple myeloma. Particular emphasis is placed on the pre-clinical research data that became the basis for eventual clinical applications of proteasome inhibitors, an overview of the clinical development of this exciting drug class in multiple myeloma, and a appraisal of possible uses in other haematological malignancies, such non-Hodgkin's lymphomas.
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68
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Chauhan D, Hideshima T, Anderson KC. PROTEASOME INHIBITION IN MULTIPLE MYELOMA: Therapeutic Implication. Annu Rev Pharmacol Toxicol 2005; 45:465-76. [PMID: 15822185 DOI: 10.1146/annurev.pharmtox.45.120403.100037] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Normal cellular functioning requires processing of proteins regulating cell cycle, growth, and apoptosis. The ubiquitin-proteasome pathway (UBP) modulates intracellular protein degradation. Specifically, the 26S proteasome is a multienzyme protease that degrades misfolded or redundant proteins; conversely, blockade of the proteasomal degradation pathways results in accumulation of unwanted proteins and cell death. Because cancer cells are more highly proliferative than normal cells, their rate of protein translation and degradation is also higher. This notion led to the development of proteasome inhibitors as therapeutics in cancer. The FDA recently approved the first proteasome inhibitor bortezomib (Velcade™), formerly known as PS-341, for the treatment of newly diagnosed and relapsed/refractory multiple myeloma (MM). Ongoing studies are examining other novel proteasome inhibitors, in addition to bortezomib, for the treatment of MM and other cancers.
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Affiliation(s)
- Dharminder Chauhan
- The Jerome Lipper Multiple Myeloma Center, Department of Medical Oncology, Dana Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
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69
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70
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71
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Elsässer A, Vogt AM, Nef H, Kostin S, Möllmann H, Skwara W, Bode C, Hamm C, Schaper J. Human hibernating myocardium is jeopardized by apoptotic and autophagic cell death. J Am Coll Cardiol 2004; 43:2191-9. [PMID: 15193679 DOI: 10.1016/j.jacc.2004.02.053] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2002] [Revised: 01/21/2004] [Accepted: 02/17/2004] [Indexed: 10/26/2022]
Abstract
OBJECTIVES The aim of the present study was to objectify the loss of myocytes and the mechanism by which myocytes die in human hibernating myocardium (HHM). BACKGROUND Intracellular degeneration, reduced cellular protein synthesis, and the replacement fibrosis contribute to structural disintegration of HHM. METHODS In 14 patients, HHM was diagnosed by dobutamine echocardiography, radionuclide ventriculography, and thallium-201 scintigraphy. Functional recovery was documented by repeating the preoperative clinical investigations three months after successful coronary artery bypass graft surgery (CABG). During CABG, transmural biopsies were taken from the center of HHM regions and studied by electron microscopy, immunohistochemistry, the terminal deoxynucleotidyl transferase-mediated nick end-labeling (TUNEL) method, reverse transcription-polymerase chain reaction, and Western blotting. Control samples were taken from nondiseased human myocardium. RESULTS All patients showed significant improvement or normalization of the regional function of HHM. Ubiquitin-related autophagic cell death was evident ultrastructurally by the occurrence of autophagic vacuoles, cellular degeneration, and nuclear disassembly. Ubiquitin-protein complexes were found in 0.03 +/- 0.008% (control: 0%, p < 0.005) of all myocytes. The proteasome 20S subunit/total myocytes were reduced from 63.3 +/- 9.6% in control myocardium to 36.9 +/- 8.4% in HHM. Complement-9, indicating oncosis, was found in only one of 14 biopsies. TUNEL-positive myocytes were 0.002 +/- 0.0003%. Electron microscopy showed apoptotic cells in 3 of 14 samples. However, the bcl-2/bax ratio was significantly reduced. Moreover, caspase-3 messenger ribonucleic acid was 8.5 times upregulated, and caspase-3 was activated. Cell death was absent in controls. CONCLUSIONS In HHM, ubiquitin-related autophagic cell death and apoptosis cause a loss of myocytes. This plays an important role in progressive tissue damage and causes a reduction of the extent of functional recovery of HHM.
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Kaiser WJ, Kaufman JL, Offermann MK. IFN-alpha sensitizes human umbilical vein endothelial cells to apoptosis induced by double-stranded RNA. THE JOURNAL OF IMMUNOLOGY 2004; 172:1699-710. [PMID: 14734752 DOI: 10.4049/jimmunol.172.3.1699] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The ability of endothelial cells to mount an efficient antiviral response is important in restricting viral dissemination and eliminating viral infection from the endothelium and surrounding tissues. We demonstrate that dsRNA, a molecular signature of viral infection, induced apoptosis in HUVEC, and priming with IFN-alpha shortened the time between when dsRNA was encountered and when apoptosis was initiated. IFN-alpha priming induced higher levels of mRNA for dsRNA-activated protein kinase, 2'5'-oligoadenylate synthetase, and Toll-like receptor 3, transcripts that encode dsRNA-responsive proteins. dsRNA induced activation of dsRNA-activated protein kinase and nuclear translocation of transcription factors RelA and IFN regulatory factor-3 in IFN-alpha-primed HUVECs before the activation of intrinsic and extrinsic apoptotic pathways. These changes did not occur in the absence of dsRNA, and apoptosis resulting from incubation with dsRNA occurred much later when cells were not primed with IFN-alpha. The entire population of IFN-alpha-primed HUVECs underwent nuclear translocation of RelA and IFN regulatory factor-3 in response to dsRNA, whereas less than one-half of the population responded with apoptosis. When IFN-alpha-primed HUVECs were coincubated with dsRNA and proteasome inhibitors, all HUVECs were rendered susceptible to dsRNA-induced apoptosis. These studies provide evidence that many endothelial cells that are alerted to the risk of infection by IFN-alpha would undergo apoptosis sooner in response to dsRNA than non-IFN-alpha-primed cells, and this would enhance the likelihood of eliminating infected cells prior to the production of progeny virions.
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Affiliation(s)
- William J Kaiser
- Winship Cancer Institute, Emory University, Atlanta, GA 30322, USA
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Abstract
The ubiquitin-proteasome pathway plays a central role in the targeted destruction of cellular proteins, including cell cycle regulatory proteins. Because these pathways are critical for the proliferation and survival of all cells, and in particular cancerous cells, proteasome inhibition is a potentially attractive anticancer therapy. Based on encouraging cytotoxic activity, bortezomib was the first proteasome inhibitor to be evaluated in clinical trials. Efficacy and safety results from a phase 2 clinical trial contributed to approval of bortezomib for use in patients with relapsed and refractory multiple myeloma who have received at least 2 prior therapies and have demonstrated disease progression on their last therapy.
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Affiliation(s)
- Julian Adams
- Infinity Pharmaceuticals, Inc., 780 Memorial Drive, Cambridge, MA 02139, USA.
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Affiliation(s)
- Julian Adams
- Infinity Pharmaceuticals, Inc., 780 Memorial Drive, Cambridge, Massachusetts 02139, USA.
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75
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Oka T, Ungar D, Hughson FM, Krieger M. The COG and COPI complexes interact to control the abundance of GEARs, a subset of Golgi integral membrane proteins. Mol Biol Cell 2004; 15:2423-35. [PMID: 15004235 PMCID: PMC404034 DOI: 10.1091/mbc.e03-09-0699] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The conserved oligomeric Golgi (COG) complex is a soluble hetero-octamer associated with the cytoplasmic surface of the Golgi. Mammalian somatic cell mutants lacking the Cog1 (ldlB) or Cog2 (ldlC) subunits exhibit pleiotropic defects in Golgi-associated glycoprotein and glycolipid processing that suggest COG is involved in the localization, transport, and/or function of multiple Golgi processing proteins. We have identified a set of COG-sensitive, integral membrane Golgi proteins called GEARs (mannosidase II, GOS-28, GS15, GPP130, CASP, giantin, and golgin-84) whose abundances were reduced in the mutant cells and, in some cases, increased in COG-overexpressing cells. In the mutants, some GEARs were abnormally localized in the endoplasmic reticulum and were degraded by proteasomes. The distributions of the GEARs were altered by small interfering RNA depletion of epsilon-COP in wild-type cells under conditions in which COG-insensitive proteins were unaffected. Furthermore, synthetic phenotypes arose in mutants deficient in both epsilon-COP and either Cog1 or Cog2. COG and COPI may work in concert to ensure the proper retention or retrieval of a subset of proteins in the Golgi, and COG helps prevent the endoplasmic reticulum accumulation and degradation of some GEARs.
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Affiliation(s)
- Toshihiko Oka
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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76
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Sawada H, Kohno R, Kihara T, Izumi Y, Sakka N, Ibi M, Nakanishi M, Nakamizo T, Yamakawa K, Shibasaki H, Yamamoto N, Akaike A, Inden M, Kitamura Y, Taniguchi T, Shimohama S. Proteasome Mediates Dopaminergic Neuronal Degeneration, and Its Inhibition Causes α-Synuclein Inclusions. J Biol Chem 2004; 279:10710-9. [PMID: 14672949 DOI: 10.1074/jbc.m308434200] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Parkinson's disease is characterized by dopaminergic neuronal death and the presence of Lewy bodies. alpha-Synuclein is a major component of Lewy bodies, but the process of its accumulation and its relationship to dopaminergic neuronal death has not been resolved. Although the pathogenesis has not been clarified, mitochondrial complex I is suppressed, and caspase-3 is activated in the affected midbrain. Here we report that a combination of 1-methyl-4-phenylpyridinium ion (MPP(+)) or rotenone and proteasome inhibition causes the appearance of alpha-synuclein-positive inclusion bodies. Unexpectedly, however, proteasome inhibition blocked MPP(+)- or rotenone-induced dopaminergic neuronal death. MPP(+) elevated proteasome activity, dephosphorylated mitogen-activating protein kinase (MAPK), and activated caspase-3. Proteasome inhibition reversed the MAPK dephosphorylation and blocked caspase-3 activation; the neuroprotection was blocked by a p42 and p44 MAPK kinase inhibitor. Thus, the proteasome plays an important role in both inclusion body formation and dopaminergic neuronal death but these processes form opposite sides on the proteasome regulation in this model.
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Affiliation(s)
- Hideyuki Sawada
- Department of Neurology, Graduate School of Medicine, Sakyoku, Kyoto 606-8507, Japan
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Richardson PG, Hideshima T, Anderson KC. Bortezomib (PS-341): a novel, first-in-class proteasome inhibitor for the treatment of multiple myeloma and other cancers. Cancer Control 2004; 10:361-9. [PMID: 14581890 DOI: 10.1177/107327480301000502] [Citation(s) in RCA: 219] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Multiple myeloma (MM) is an incurable malignancy that is diagnosed in approximately 15,000 people in the United States each year. The novel proteasome inhibitor bortezomib has shown antitumor activity in preclinical studies and has entered clinical trials, with encouraging results to date. METHODS We review and summarize preclinical work demonstrating the tumoricidal effects of proteasome inhibition, focusing on the potent and selective proteasome inhibitor bortezomib, the first such agent to progress to clinical trials. We also address the potential for bortezomib as a therapy for MM. RESULTS In preclinical studies bortezomib appears not only to have activity against MM cells, but also to downregulate protective interactions with bone marrow stromal cells and to inhibit blood vessel development. Proteasome inhibition also has been shown to interfere with protective interactions between MM cells and the bone marrow, and to restrict tumor-associated angiogenesis in preclinical models. CONCLUSIONS Proteasome inhibition is a promising new investigational avenue for cancer therapy. Bortezomib is currently available for the treatment of relapsed and refractory MM. Further trials are underway to assess the safety and efficacy of this agent in MM and a range of other cancers.
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Affiliation(s)
- Paul G Richardson
- Jerome Lipper Myeloma Center, Division of Hematologic Oncology, Department of Adult Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA.
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78
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Laurent N, de Boüard S, Guillamo JS, Christov C, Zini R, Jouault H, Andre P, Lotteau V, Peschanski M. Effects of the proteasome inhibitor ritonavir on glioma growth in vitro and in vivo. Mol Cancer Ther 2004. [DOI: 10.1158/1535-7163.129.3.2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Glioblastoma is a therapeutic challenge as a highly infiltrative, proliferative, and resistant tumor. Among novel therapeutic approaches, proteasome inhibition is very promising in controlling cell cycle and inducing apoptosis. This study investigated the effect of ritonavir, a protease inhibitor of the HIV and a proteasome modulator, on glioma cells. The hypothesis was that proteasome modulation, mainly by only inhibiting proteasome chymotrypsin-like activity, could be sufficient to control tumor progression. The experiments were done on a human glioblastoma-derived GL15 cell line and a rat nitrosourea-induced gliosarcoma 9L cell line. Culturing conditions included monolayer cultures, transplantations into brain slices, and transplantations into rat striata. The study demonstrates that ritonavir, by inhibiting the chymotrypsin-like activity of the proteasome, has cytostatic and cytotoxic effects on glioma cells, and can induce resistances in vitro. Ritonavir was unable to control tumor growth in vivo, likely because the therapeutic dose was not reached in the tumor in vivo. Nevertheless, ritonavir might also be beneficial, by decreasing tumor infiltration, in the reduction of the deleterious peritumor edema in glioblastoma.
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Affiliation(s)
- Nathalie Laurent
- 1INSERM U421, Faculté de Médecine 2ème étage, Creteil, France
| | | | | | - Christo Christov
- 1INSERM U421, Faculté de Médecine 2ème étage, Creteil, France
| | - Roland Zini
- 2Département de pharmacologie, Faculté de Médecine 1er étage, Creteil, France
| | - Hélène Jouault
- 3Service d'hématologie, Hôpital Henri Mondor, Creteil, France; and
| | | | | | - Marc Peschanski
- 1INSERM U421, Faculté de Médecine 2ème étage, Creteil, France
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Jana NR, Dikshit P, Goswami A, Nukina N. Inhibition of proteasomal function by curcumin induces apoptosis through mitochondrial pathway. J Biol Chem 2003; 279:11680-5. [PMID: 14701837 DOI: 10.1074/jbc.m310369200] [Citation(s) in RCA: 183] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Curcumin is a natural polyphenolic compound having an antiproliferative property, which recent evidence suggests is due to its ability to induce apoptosis. However, the molecular mechanisms through which curcumin induces apoptosis are not fully understood. Here, we report that the curcumin-induced apoptosis is mediated through the impairment of the ubiquitin-proteasome system. Exposure of curcumin to the mouse neuro 2a cells causes a dose-dependent decrease in proteasome activity and an increase in ubiquitinated proteins. Curcumin exposure also decreases the turnover of the destabilized enhanced green fluorescence protein, a model substrate for proteasome and cellular p53 protein. Like other proteasome inhibitors, curcumin targets proliferative cells more efficiently than differentiated cells and induces apoptosis via mitochondrial pathways. Addition of curcumin to neuro 2a cells induces a rapid decrease in mitochondrial membrane potential and the release of cytochrome c into cytosol, followed by activation of caspase-9 and caspase-3.
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Affiliation(s)
- Nihar Ranjan Jana
- Cellular and Molecular Neuroscience Laboratory, National Brain Research Centre, Manesar, Gurgaon 122050, India.
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80
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Rao RV, Poksay KS, Castro-Obregon S, Schilling B, Row RH, del Rio G, Gibson BW, Ellerby HM, Bredesen DE. Molecular components of a cell death pathway activated by endoplasmic reticulum stress. J Biol Chem 2003; 279:177-87. [PMID: 14561754 DOI: 10.1074/jbc.m304490200] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Alterations in Ca2+ homeostasis and accumulation of misfolded proteins in the endoplasmic reticulum (ER) cause ER stress that ultimately leads to programmed cell death. Recent studies have shown that ER stress triggers programmed cell death via an alternative intrinsic pathway of apoptosis that, unlike the intrinsic pathway described previously, is independent of Apaf-1 and cytochrome c. In the present work, we have used a set of complementary approaches, including two-dimensional gel electrophoresis coupled with matrix-assisted laser desorption ionization-time-of-flight mass spectrometry and nano-liquid chromatography-electrospray ionization mass spectrometry with tandem mass spectrometry, RNA interference, co-immunoprecipitation, immunodepletion of candidate proteins, and reconstitution studies, to identify mediators of the ER stress-induced cell death pathway. Our data identify two molecules, valosin-containing protein and apoptosis-linked gene-2 (ALG-2), that appear to play a role in mediating ER stress-induced cell death.
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Affiliation(s)
- Rammohan V Rao
- The Buck Institute for Age Research, Novato, California 94945, USA
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81
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King AR, Francis SE, Bridgeman CJ, Bird H, Whyte MKB, Crossman DC. A role for caspase-1 in serum withdrawal-induced apoptosis of endothelial cells. J Transl Med 2003; 83:1497-508. [PMID: 14563951 DOI: 10.1097/01.lab.0000093096.62765.85] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Mouse lung endothelial cells (MLEC) and HUVEC were used under serum withdrawal (SW) conditions as a model of endothelial cell (EC) apoptosis. Apoptosis was quantified by time-lapse video microscopy. Mouse lung ECs from caspase-1(-/-) mice had significantly reduced rates of SW-induced apoptosis compared with wild-type mice, specifically implicating caspase-1 in proapoptotic signaling in ECs. SW conditions induced HUVEC apoptosis with concomitant activation of caspase-1. Further studies demonstrated that the caspase-1 inhibitors z-VAD and z-YVAD significantly reduced the rate of SW-induced HUVEC apoptosis. HUVEC, when transfected with caspase-1, showed a highly significant increase in apoptosis. SW was associated with increases in reactive oxygen species production that were significantly inhibited by the antioxidant N-acetyl-L-cysteine, although rates of apoptosis and caspase-1 activation were unaffected. These results demonstrate the involvement of caspase-1 in SW-induced EC apoptosis, independently of reactive oxygen species production.
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Affiliation(s)
- Andrea R King
- Cardiovascular Research Group, Division of Clinical Sciences (North), Clinical Sciences Centre, University of Sheffield, Northern General Hospital, Sheffield, United Kingdom.
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82
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Chondrogianni N, Stratford FLL, Trougakos IP, Friguet B, Rivett AJ, Gonos ES. Central role of the proteasome in senescence and survival of human fibroblasts: induction of a senescence-like phenotype upon its inhibition and resistance to stress upon its activation. J Biol Chem 2003; 278:28026-37. [PMID: 12736271 DOI: 10.1074/jbc.m301048200] [Citation(s) in RCA: 239] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Normal human fibroblasts undergo a limited number of divisions in culture and progressively they reach a state of irreversible growth arrest, a process termed as replicative senescence. The proteasome is the major cellular proteolytic machinery, the function of which is impaired during replicative senescence. However, the exact causes of its malfunction in these conditions are unknown. Using WI38 fibroblasts as a model for cellular senescence we have observed reduced levels of proteasomal peptidase activities coupled with increased levels of both oxidized and ubiquitinated proteins in senescent cells. We have found the catalytic subunits of the 20 S complex and subunits of the 19 S regulatory complex to be down-regulated in senescent cells. This is accompanied by a decrease in the level of both 20 S and 26 S complexes. Partial inhibition of proteasomes in young cells caused by treatment with specific inhibitors induced a senescence-like phenotype, thus demonstrating the fundamental importance of the proteasome for retaining cellular maintenance and homeostasis. Stable overexpression of beta1 and beta5 subunits in WI38 established cell lines was shown to induce elevated expression levels of beta1 subunit in beta5 transfectants and vice versa. Transfectants possess increased proteasome activities and most importantly, increased capacity to cope better with various stresses. In summary these data demonstrate the central role of the proteasome during cellular senescence and survival as well as provide insights toward a better understanding of proteasome regulation.
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Affiliation(s)
- Niki Chondrogianni
- National Hellenic Research Foundation, Institute of Biological Research and Biotechnology, 48 Vas. Constantinou Ave., Athens 11635, Greece
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83
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Koczulla R, von Degenfeld G, Kupatt C, Krötz F, Zahler S, Gloe T, Issbrücker K, Unterberger P, Zaiou M, Lebherz C, Karl A, Raake P, Pfosser A, Boekstegers P, Welsch U, Hiemstra PS, Vogelmeier C, Gallo RL, Clauss M, Bals R. An angiogenic role for the human peptide antibiotic LL-37/hCAP-18. J Clin Invest 2003. [PMID: 12782669 DOI: 10.1172/jci200317545] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Antimicrobial peptides are effector molecules of the innate immune system and contribute to host defense and regulation of inflammation. The human cathelicidin antimicrobial peptide LL-37/hCAP-18 is expressed in leukocytes and epithelial cells and secreted into wound and airway surface fluid. Here we show that LL-37 induces angiogenesis mediated by formyl peptide receptor-like 1 expressed on endothelial cells. Application of LL-37 resulted in neovascularization in the chorioallantoic membrane assay and in a rabbit model of hind-limb ischemia. The peptide directly activates endothelial cells, resulting in increased proliferation and formation of vessel-like structures in cultivated endothelial cells. Decreased vascularization during wound repair in mice deficient for CRAMP, the murine homologue of LL-37/hCAP-18, shows that cathelicidin-mediated angiogenesis is important for cutaneous wound neovascularization in vivo. Taken together, these findings demonstrate that LL-37/hCAP-18 is a multifunctional antimicrobial peptide with a central role in innate immunity by linking host defense and inflammation with angiogenesis and arteriogenesis.
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Affiliation(s)
- Rembert Koczulla
- Hospital of the University of Marburg, Department of Internal Medicine, Philipps Universtät Marburg, Marburg, Germany
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84
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Koczulla R, von Degenfeld G, Kupatt C, Krötz F, Zahler S, Gloe T, Issbrücker K, Unterberger P, Zaiou M, Lebherz C, Karl A, Raake P, Pfosser A, Boekstegers P, Welsch U, Hiemstra PS, Vogelmeier C, Gallo RL, Clauss M, Bals R. An angiogenic role for the human peptide antibiotic LL-37/hCAP-18. J Clin Invest 2003; 111:1665-72. [PMID: 12782669 PMCID: PMC156109 DOI: 10.1172/jci17545] [Citation(s) in RCA: 607] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Antimicrobial peptides are effector molecules of the innate immune system and contribute to host defense and regulation of inflammation. The human cathelicidin antimicrobial peptide LL-37/hCAP-18 is expressed in leukocytes and epithelial cells and secreted into wound and airway surface fluid. Here we show that LL-37 induces angiogenesis mediated by formyl peptide receptor-like 1 expressed on endothelial cells. Application of LL-37 resulted in neovascularization in the chorioallantoic membrane assay and in a rabbit model of hind-limb ischemia. The peptide directly activates endothelial cells, resulting in increased proliferation and formation of vessel-like structures in cultivated endothelial cells. Decreased vascularization during wound repair in mice deficient for CRAMP, the murine homologue of LL-37/hCAP-18, shows that cathelicidin-mediated angiogenesis is important for cutaneous wound neovascularization in vivo. Taken together, these findings demonstrate that LL-37/hCAP-18 is a multifunctional antimicrobial peptide with a central role in innate immunity by linking host defense and inflammation with angiogenesis and arteriogenesis.
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Affiliation(s)
- Rembert Koczulla
- Hospital of the University of Marburg, Department of Internal Medicine, Philipps Universtät Marburg, Marburg, Germany
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85
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Kim JM, Bae HR, Park BS, Lee JM, Ahn HB, Rho JH, Yoo KW, Park WC, Rho SH, Yoon HS, Yoo YH. Early mitochondrial hyperpolarization and intracellular alkalinization in lactacystin-induced apoptosis of retinal pigment epithelial cells. J Pharmacol Exp Ther 2003; 305:474-81. [PMID: 12606642 DOI: 10.1124/jpet.102.047811] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated the induction and underlying mechanism of apoptosis in retinal pigment epithelial cells by the inhibition of proteasome activity using lactacystin. Rat retinal pigment epithelial cell line retinal pigment epithelial (RPE)-J was used in this study. Apoptosis was evaluated by light and electron microscopies, DNA electrophoresis, and terminal deoxynucleotidyl transferase dUTP nick-end labeling assay. The apoptosis-related proteins were localized in the cells by immunofluorescent microscopy, and the changes of their protein contents and the enzyme activation were monitored by Western blot. Mitochondrial membrane potential was quantified by measuring J aggregate (5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazol carbocyanine iodide) fluorescence. To measure changes in intracellular pH, cells were loaded with 2',7'-bis(carboxyethyl)-5(6')-carboxyfluorescein and assayed by flow cytometry. To elucidate the type of transport system involving intracellular pH regulation, several transporter inhibitors were used, and their effect on pH and membrane potential was assayed as described above. Lactacystin treatment significantly induced apoptosis in RPE-J cells. During the RPE cell apoptosis, 1) cytochrome c and Smac/DIABLO were released into cytosol from mitochondria, 2) translocation of apoptosis-inducing factor to the nucleus was evident, 3) Bax protein seemed to translocate to mitochondria, 4) procaspase-3 and poly(ADP-ribose) polymerase were cleaved, and 5) nuclear condensation and DNA fragmentation were clearly observed. Noticeably, a transient increase of mitochondrial membrane potential was coincidentally detected with the intracellular alkalinization after lactacystin administration. Furthermore, the lactacystin-induced early alkalinization was inhibited by 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonate, an inhibitor of Cl(-)/HCO(3)(-) anion exchanger, which also prevented early mitochondrial hyperpolarization and apoptosis. Lactacystin-induced apoptosis in RPE-J cells is closely associated with an early mitochondrial hyperpolarization induced by intracellular alkalinization.
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Affiliation(s)
- Jong-M Kim
- Department of Anatomy and Cell Biology, Dong-A University College of Medicine, 3-1 Dongdaesin-Dong, Seo-Gu, Busan, South Korea 602-714
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86
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Drexler HCA, Pebler S. Inducible p27(Kip1) expression inhibits proliferation of K562 cells and protects against apoptosis induction by proteasome inhibitors. Cell Death Differ 2003; 10:290-301. [PMID: 12700629 DOI: 10.1038/sj.cdd.4401159] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Overexpression of the cyclin-dependent kinase inhibitor p27(Kip1) has been demonstrated to induce cell cycle arrest and apoptosis in various cancer cell lines, but has also been associated with the opposite effect of enhanced survival of tumor cells and increased resistance towards chemotherapeutic treatment. To address the question of how p27(Kip1) expression is related to apoptosis induction, we studied doxycycline-regulated p27(Kip1) expression in K562 erythroleukemia cells. p27(Kip1) expression effectively retards proliferation, but it is not sufficient to induce apoptosis in K562 cells. p27(Kip1)-expressing K562 cells, however, become resistant to apoptosis induction by the proteasome inhibitors PSI, MG132 and epoxomicin, in contrast to wild-type K562 cells that are efficiently killed. Cell cycle arrest in the S phase by aphidicolin, which is not associated with an accumulation of p27(Kip1) protein, did not protect K562 cells against the cytotoxic effect of the proteasome inhibitor PSI. The expression levels of p27(Kip1) thus constitute an important parameter, which decides on the overall sensitivity of cells against the cytotoxic effect of proteasome inhibitors.
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Affiliation(s)
- H C A Drexler
- Max Planck Institute for Physiological and Clinical Research, Department of Molecular Cell Biology, Bad Nauheim, Germany.
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87
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Seo SY, Jun EJ, Jung SM, Kim KH, Lim YJ, Park BS, Kim JK, Lee S, Suh H, Kim ND, Yoo YH. Synthetic chenodeoxycholic acid derivative HS-1200-induced apoptosis of p815 mastocytoma cells is augmented by co-treatment with lactacystin. Anticancer Drugs 2003; 14:219-25. [PMID: 12634616 DOI: 10.1097/00001813-200303000-00005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The antitumor activity of a synthetic chenodeoxycholic acid derivative, HS-1200, on the p815 mastocytoma cell line was investigated. We present several lines of evidence indicating that HS-1200 at 35 microM induced apoptosis of p815 cells. Reduction of mitochondrial membrane potential, the release of cytochrome to cytosol, activation of caspase-3, nuclear condensation, production of poly(ADP-ribose) polymerase cleavage, generation of DNA fragmentation and nuclear condensation were demonstrated. Importantly, HS-1200 inhibited proteasome activity. Next, the combination treatment of HS-1200 or a proteasome inhibitor lactacystin was undertaken. Although the single treatment of 20 microM HS-1200 or 1 microM lactacystin induced apoptosis slightly, the combination treatment of them augmented prominently the extent of apoptosis. The combination therapy of HS-1200 and lactacystin could be potentially a therapeutic strategy reducing the extent and severity of treatment-related toxicity.
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Affiliation(s)
- Su Yeong Seo
- Department of Microbiology and Immunology, Dong-A University College of Medicine and Institute of Medical Science, Seo Gu, Busan, South Korea
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88
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Bogner C, Schneller F, Hipp S, Ringshausen I, Peschel C, Decker T. Cycling B-CLL cells are highly susceptible to inhibition of the proteasome: involvement of p27, early D-type cyclins, Bax, and caspase-dependent and -independent pathways. Exp Hematol 2003; 31:218-25. [PMID: 12644019 DOI: 10.1016/s0301-472x(02)01076-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Although peripheral blood B-CLL cells are arrested in G0 phase of the cell cycle, a proliferating pool of cells in proliferation centers might be involved in disease progression. We have previously described an in vitro model of this proliferating pool of cells using B-CLL cells stimulated with immunostimulatory oligonucleotides (CpG-ODN) and interleukin-2. Lactacystin is a specific inhibitor of the proteasome and is a potent apoptosis inductor in resting peripheral B-CLL cells. In the present study, we investigated the effect of proteasome inhibition in proliferating B-CLL cells. METHODS The effect of proteasome inhibition was analyzed using thymidine incorporation, annexin V assays, and TUNEL staining. Immunoblots were performed to evaluate expression of proteins involved in cell cycle and apoptosis regulation. RESULTS Lactacystin blocked cell cycle progression in activated B-CLL cells and inhibited degradation of p27. Upregulation of cyclin D2 and D3 in activated B-CLL cells was inhibited while the expression of cdk2, cdk4, and cyclin E remained unchanged. Activated B-CLL cells were more susceptible to apoptosis induction as compared to resting B-CLL cells. Apoptosis induction was accompanied by cleavage of Bax, procaspase 8, procaspase 9, and procaspase 3. However, a broad-spectrum caspase inhibitor (z-VAD.fmk) only partially inhibited cell death although DNA degradation was completely inhibited. CONCLUSION Proteasome inhibition is highly effective in proliferating B-CLL cells and induces apoptosis using a caspase-dependent and -independent pathway.
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Affiliation(s)
- Christian Bogner
- IIIrd Department of Medicine, Technical University of Munich, Munich, Germany
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89
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Issbrücker K, Marti HH, Hippenstiel S, Springmann G, Voswinckel R, Gaumann A, Breier G, Drexler HCA, Suttorp N, Clauss M. p38 MAP kinase--a molecular switch between VEGF-induced angiogenesis and vascular hyperpermeability. FASEB J 2003; 17:262-4. [PMID: 12490545 DOI: 10.1096/fj.02-0329fje] [Citation(s) in RCA: 140] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Vascular endothelial growth factor (VEGF) is not only essential for vasculogenesis and angiogenesis but also is a potent inducer of vascular permeability. Although a dissection of the molecular pathways between angiogenesis- and vascular permeability-inducing properties would be desirable for the development of angiogenic and anti-angiogenic therapies, such mechanisms have not been identified yet. Here we provide evidence for a role of the p38 MAPK as the signaling molecule that separates these two processes. Inhibition of p38 MAPK activity enhances VEGF-induced angiogenesis in vitro and in vivo, a finding that was accompanied by prolonged Erk1/2 MAPK activation, increased endothelial survival, and plasminogen activation. Conversely, the same inhibitors abrogate VEGF-induced vascular permeability in vitro and in vivo. These dualistic properties of p38 MAPK are relevant not only for therapeutic angiogenesis but also for reducing edema formation and enhancing tissue repair in ischemic diseases.
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Affiliation(s)
- Katja Issbrücker
- Department of Molecular Cell Biology, Max-Planck-Institute for Physiological and Clinical Research, 61231 Bad Nauheim, Germany
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90
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Fang S, Lorick KL, Jensen JP, Weissman AM. RING finger ubiquitin protein ligases: implications for tumorigenesis, metastasis and for molecular targets in cancer. Semin Cancer Biol 2003; 13:5-14. [PMID: 12507552 DOI: 10.1016/s1044-579x(02)00095-0] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Covalent modification of proteins with ubiquitin regulates almost all aspects of eukaryotic cellular function. Ubiquitin protein ligases (E3s) play central regulatory roles in that they provide substrate specificity to this process and therefore, represent attractive molecular targets for disease therapy. We summarize recent advances in our understanding of RING finger and RING finger-related E3s with emphasis on BRCA1 and the tumor autocrine motility factor receptor (gp78), as well as discuss the potential for components of the ubiquitin pathway for proteasomal degradation as molecular targets.
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Affiliation(s)
- Shengyun Fang
- Regulation of Protein Function Laboratory, Center for Cancer Research, National Cancer Institute at Frederick, Building 560, Room 22-95, 1050 Boyles Street, Frederick, MD 21702, USA
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91
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Abstract
The targeted degradation of key regulatory proteins is an essential element of cell cycle control. The proteasome plays a central role in the degradation of such proteins and has therefore become an important therapeutic target for diseases involving cell proliferation, notably cancer. This review summarizes numerous studies demonstrating that proteasome inhibition induces apoptosis and sensitizes cancer cells to traditional tumoricidal agents both and The potent and selective proteasome inhibitor, PS-341, is particularly promising from a therapeutic perspective, and it is the only such inhibitor that has progressed to clinical trials. Preliminary data indicate that the drug is well tolerated by patients with cancer, and further trials are underway to assess the safety and efficacy of proteasome inhibition in hematologic and solid tumors, both as a monotherapy and in combination with other chemotherapeutics.
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Affiliation(s)
- Julian Adams
- Millennium Pharmaceuticals, Cambridge, Massachusetts 02139, USA.
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92
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Abstract
The 26S proteasome constitutes the central proteolytic machinery of the highly conserved ubiquitin/proteasome system, the cell's major tool for extralysosomal protein degradation. Recently, a plethora of cell proteins implicated in the regulation of basic cellular processes, such as proliferation, differentiation, cell cycling, and apoptosis have been discovered to undergo processing and functional limitation by entering the ubiquitin/proteasome pathway with the final destination to be proteolytically degraded by the 26S proteasome. Because both negative and positive regulators of proliferation and apoptosis undergo proteasomal degradation in a tightly regulated and temporally controlled fashion, the 26S proteasome can play opposite roles in the regulation of proliferation and apoptosis. These roles are apparently defined by the cell's environment and proliferative state. Finally, proteasomal protein degradation is deregulated in a number of human diseases, including cancer and neurodegenerative and myodegenerative diseases, which all exhibit an imbalance of proliferation and apoptosis. An improved understanding of the modes of proteasomal action should lead to the development of beneficial therapeutic and diagnostic strategies in the future.
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Affiliation(s)
- Cord Naujokat
- Institute of Immunology (CN), Department of Transplantation Immunology, University of Heidelberg, Germany.
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93
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Almond JB, Cohen GM. The proteasome: a novel target for cancer chemotherapy. Leukemia 2002; 16:433-43. [PMID: 11960320 DOI: 10.1038/sj.leu.2402417] [Citation(s) in RCA: 390] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2001] [Accepted: 11/09/2001] [Indexed: 02/07/2023]
Abstract
The ubiquitin-proteasome system is an important regulator of cell growth and apoptosis. The potential of specific proteasome inhibitors to act as novel anti-cancer agents is currently under intensive investigation. Several proteasome inhibitors exert anti-tumour activity in vivo and potently induce apoptosis in tumour cells in vitro, including those resistant to conventional chemotherapeutic agents. By inhibiting NF-kappaB transcriptional activity, proteasome inhibitors may also prevent angiogenesis and metastasis in vivo and further increase the sensitivity of cancer cells to apoptosis. Proteasome inhibitors also exhibit some level of selective cytotoxicity to cancer cells by preferentially inducing apoptosis in proliferating or transformed cells or by overcoming deficiencies in growth-inhibitory or pro-apoptotic molecules. High expression of oncogene products like c-Myc also makes cancer cells more susceptible to proteasome inhibitor-induced apoptosis. The induction of apoptosis by proteasome inhibitors varies between cell types but often occurs following an initial accumulation of short-lived proteins such as p53, p27, pro-apoptotic Bcl-2 family members or activation of the stress kinase JNK. These initial events often result in a perturbation of mitochondria with concomitant release of cytochrome c and activation of the Apaf-1 containing apoptosome complex. This results in activation of the apical caspase-9 followed by activation of effector caspases-3 and -7, which are responsible for the biochemical and morphological changes associated with apoptosis.
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Affiliation(s)
- J B Almond
- MRC Toxicology Unit, University of Leicester, Leicester, UK
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94
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Kisselev AF, Goldberg AL. Proteasome inhibitors: from research tools to drug candidates. CHEMISTRY & BIOLOGY 2001; 8:739-58. [PMID: 11514224 DOI: 10.1016/s1074-5521(01)00056-4] [Citation(s) in RCA: 873] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The 26S proteasome is a 2.4 MDa multifunctional ATP-dependent proteolytic complex, which degrades the majority of cellular polypeptides by an unusual enzyme mechanism. Several groups of proteasome inhibitors have been developed and are now widely used as research tools to study the role of the ubiquitin-proteasome pathway in various cellular processes, and two inhibitors are now in clinical trials for treatment of multiple cancers and stroke.
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Affiliation(s)
- A F Kisselev
- Department of Cell Biology, Harvard Medical School, 240 Longwood Ave., Boston, MA 02115, USA.
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95
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Abstract
OBJECTIVE To examine the role of nuclear factor kappaB (NF-kappaB) and caspases 3, 8, and 9 in CD95-mediated apoptosis of normal chondrocytes. METHODS First-passage chondrocytes from normal human knee cartilage were stimulated with CD95 antibody, and cell death was determined by annexin V binding and by an enzyme-linked immunosorbent assay. Activation of caspases 3, 8, and 9 was measured by Western blotting, and their role in death signaling was evaluated using caspase-specific small peptide inhibitors. The influence of NF-kappaB was determined by electrophoretic mobility shift assay (EMSA) and proteasome inhibition-dependent blocking of the degradation of inhibitor of NF-kappaB. RESULTS Low levels of NF-kappaB activity were detected by EMSA in unstimulated chondrocytes. NF-kappaB activity was increased in response to agonistic CD95 antibody. CD95 antibody-induced apoptosis was potentiated by the proteasome inhibitors MG-132 and PS1, and this was associated with a reduced nuclear translocation of NF-kappaB. Proteasome inhibitors also caused the induction of DNA fragmentation by tumor necrosis factor alpha. Procaspase 3 processing was enhanced by the proteasome inhibitor MG-132. Procaspase 8 was undetectable by immunoblotting in whole cell lysates of chondrocytes, but caspase 8 messenger RNA was detected by reverse transcription-polymerase chain reaction. Furthermore, apoptosis induced by CD95 stimulation and proteasome inhibitors was blocked by the caspase 8-specific inhibitor Ac-IETD-CHO. Processing of procaspase 9 was not observed, and inhibition of CD95-dependent cell death by the caspase 9 inhibitor Ac-LEHD-CHO was not significant. CONCLUSION These results suggest that CD95-dependent cell death is enhanced by NF-kappaB inhibition at and/or downstream of caspase 8 activation and that caspase 9 activation is not involved in CD95-mediated apoptosis in chondrocytes.
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Affiliation(s)
- K Kühn
- The Scripps Research Institute, La Jolla, California 92037, USA
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96
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Tenev T, Marani M, McNeish I, Lemoine NR. Pro-caspase-3 overexpression sensitises ovarian cancer cells to proteasome inhibitors. Cell Death Differ 2001; 8:256-64. [PMID: 11319608 DOI: 10.1038/sj.cdd.4400808] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2000] [Revised: 09/22/2000] [Accepted: 11/02/2000] [Indexed: 11/09/2022] Open
Abstract
The ubiquitin-proteasome pathway plays a critical role in the degradation of several proteins involved in the cell cycle. Dysregulation of this pathway leads to inhibition of cellular proliferation and the induction of apoptosis. Ubiquitination and its downstream consequences have been investigated intensively as targets for the development of drugs for tumour therapy. Here we have investigated the mechanism of apoptosis induced by the proteasome inhibitors MG-132, lactacystin and calpain inhibitor I (ALLN), in the HEK 293 cell line and the ovarian cancer cell lines SKOV3 and OVCAR3. We have found strong caspase-3-like and caspase-6-like activation upon treatment of HEK 293 cells with MG-132. Using a tricistronic expression vector based on a tetracycline-responsive system we generated stable SKOV3 nd OVCAR3 cell lines with inducible expression of pro-caspase-3. Induction of pro-caspase-3 expression in normally growing cells does not induce apoptosis. However, in the presence of the proteasome inhibitors MG-132, lactacystin or ALLN we found that cells overexpressing pro-caspase-3 are rapidly targeted for apoptosis. Our results demonstrate that pro-caspase-3 can sensitise ovarian cancer cells to proteasome inhibitor-induced apoptosis, and a combination of these approaches might be exploited for therapy of ovarian and other cancers.
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Affiliation(s)
- T Tenev
- ICRF Molecular Oncology Unit, Imperial College School of Medicine at Hammersmith Hospital, London W12 ONN, UK
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97
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Levkau B, Garton KJ, Ferri N, Kloke K, Nofer JR, Baba HA, Raines EW, Breithardt G. xIAP induces cell-cycle arrest and activates nuclear factor-kappaB : new survival pathways disabled by caspase-mediated cleavage during apoptosis of human endothelial cells. Circ Res 2001; 88:282-90. [PMID: 11179195 DOI: 10.1161/01.res.88.3.282] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Survival of human vascular endothelial cells depends on their ability to activate the transcription factor nuclear factor-kappaB (NF-kappaB), a regulator of antiapoptotic genes, such as the X chromosome-linked inhibitor of apoptosis protein (xIAP). In the present study, we demonstrated expression of xIAP in the endothelial lining of normal human arteries and veins and elevated levels in highly malignant human endothelial tumors. Using retroviral infection of human endothelial cells, we identified two novel survival mechanisms mediated by xIAP in endothelial cells. First, xIAP can activate the transcription factor NF-kappaB, a known survival factor for human endothelial cells. This positive feedback loop induced by xIAP is mediated via phosphorylation and sustained degradation of inhibitor (I) kappaBalpha. Second, xIAP can inhibit cell proliferation via downregulation of cyclins A and D1 and induction of the cyclin-dependent kinase inhibitors p21(Cip1/Waf1) and p27(Kip1). Cleavage of xIAP by caspases during endothelial cell apoptosis disables both of these biological functions of xIAP. Thus, caspase-mediated cleavage of xIAP interrupts a positive regulatory cytoprotective loop between NF-kappaB and xIAP and increases the vulnerability of the cell to apoptosis by releasing it from an xIAP-mediated quiescent state.
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Affiliation(s)
- B Levkau
- Institute of Arteriosclerosis Research, University of Münster, Münster, Germany
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98
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Kupatt C, Wichels R, Becker BF, Boekstegers P. Inhibition of post-ischaemic inflammation as a therapeutic approach to myocardial ischaemia reperfusion injury. Expert Opin Ther Pat 2000. [DOI: 10.1517/13543776.10.9.1395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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99
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100
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Abstract
The ubiquitin (Ub)-proteasome pathway is the major nonlysosomal pathway of proteolysis in human cells and accounts for the degradation of most short-lived, misfolded or damaged proteins. This pathway is important in the regulation of a number of key biological regulatory mechanisms. Proteins are usually targeted for proteasome-mediated degradation by polyubiquitinylation, the covalent addition of multiple units of the 76 amino acid protein Ub, which are ligated to 1-amino groups of lysine residues in the substrate. Polyubiquitinylated proteins are degraded by the 26S proteasome, a large, ATP-dependent multicatalytic protease complex, which also regenerates monomeric Ub. The targets of this pathway include key regulators of cell proliferation and cell death. An alternative form of the proteasome, termed the immunoproteasome, also has important functions in the generation of peptides for presentation by MHC class I molecules. In recent years there has been a great deal of interest in the possibility that proteasome inhibitors, through elevation of the levels of proteasome targets, might prove useful as a novel class of anti-cancer drugs. Here we review the progress made to date in this area and highlight the potential advantages and weaknesses of this approach.
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Affiliation(s)
- R Z Murray
- Imperial Cancer Research Fund Molecular Oncology Laboratory, University of Oxford Institute of Molecular Medicine, John Radcliffe Hospital, UK
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