Proteasome inhibitors as therapeutics

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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Carfilzomib: A Promising Proteasome Inhibitor for the Treatment of Relapsed and Refractory Multiple Myeloma

Frontiers in Oncology ◽

10.3389/fonc.2021.740796 ◽

2021 ◽

Vol 11 ◽

Author(s):

Shansa Pranami E. Jayaweera ◽

Sacheela Prasadi Wanigasinghe Kanakanamge ◽

Dharshika Rajalingam ◽

Gayathri N. Silva

Keyword(s):

Multiple Myeloma ◽

Proteasome Inhibitor ◽

Proteasome Inhibitors ◽

Biochemical Properties ◽

Regulatory Proteins ◽

Toxicity Profile ◽

The Us ◽

Intracellular Proteins ◽

Ubiquitin Proteasome ◽

Proteasome Pathway

The proteasome is crucial for the degradation of intracellular proteins and plays an important role in mediating a number of cell survival and progression events by controlling the levels of key regulatory proteins such as cyclins and caspases in both normal and tumor cells. However, compared to normal cells, cancer cells are more dependent on the ubiquitin proteasome pathway (UPP) due to the accumulation of proteins in response to uncontrolled gene transcription, allowing proteasome to become a potent therapeutic target for human cancers such as multiple myeloma (MM). Up to date, three proteasome inhibitors namely bortezomib (2003), carfilzomib (2012) and ixazomib (2015) have been approved by the US Food and Drug Administration (FDA) for the treatment of patients with relapsed and/or refractory MM. This review mainly focuses on the biochemical properties, mechanism of action, toxicity profile and pivotal clinical trials related to carfilzomib, a second-generation proteasome inhibitor that binds irreversibly with proteasome to overcome the major toxicities and resistance associated with bortezomib.

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PROTEASOME INHIBITION IN MULTIPLE MYELOMA: Therapeutic Implication

The Annual Review of Pharmacology and Toxicology ◽

10.1146/annurev.pharmtox.45.120403.100037 ◽

2005 ◽

Vol 45 (1) ◽

pp. 465-476 ◽

Cited By ~ 98

Author(s):

Dharminder Chauhan ◽

Teru Hideshima ◽

Kenneth C. Anderson

Keyword(s):

Multiple Myeloma ◽

Proteasome Inhibitors ◽

Proteasome Inhibition ◽

Protein Translation ◽

26S Proteasome ◽

Intracellular Protein ◽

Cycle Growth ◽

Intracellular Protein Degradation ◽

Ubiquitin Proteasome ◽

Proteasome Pathway

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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Abstract 37: Centrosome Destabilization Through the Ubiquitin-Proteasome Pathway Regulates Proplatelet Production

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.37.suppl_1.37 ◽

2017 ◽

Vol 37 (suppl_1) ◽

Author(s):

Kellie R Machlus ◽

Prakrith Vijey ◽

Thomas Soussou ◽

Joseph E Italiano

Keyword(s):

Protein Degradation ◽

Proteasome Inhibitors ◽

Aurora Kinase ◽

Proteasome Activity ◽

Major Pathway ◽

Ubiquitin Proteasome Pathway ◽

Ubiquitin Proteasome ◽

Proteasome Pathway ◽

Proplatelet Formation

Background: Proteasome inhibitors such as bortezomib, a chemotherapeutic used to treat multiple myeloma, induce thrombocytopenia within days of initiation. The mechanism for this thrombocytopenia has been tied to data revealing that proteasome activity is essential for platelet formation. The major pathway of selective protein degradation uses ubiquitin as a marker that targets proteins for proteolysis by the proteasome. This pathway is previously unexplored in megakaryocytes (MKs). Objectives: We aim to define the mechanism by which the ubiquitin-proteasome pathway affects MK maturation and platelet production. Results: Pharmacologic inhibition of proteasome activity blocks proplatelet formation in megakaryocytes. To further characterize how this degradation was occurring, we probed distinct ubiquitin pathways. Inhibition of the ubiquitin-activating enzyme E1 significantly inhibited proplatelet formation up to 73%. In addition, inhibition of the deubiquitinase proteins UCHL5 and USP14 significantly inhibited proplatelet formation up to 83%. These data suggest that an intact ubiquitin pathway is necessary for proplatelet formation. Proteomic and polysome analyses of MKs undergoing proplatelet formation revealed a subset of proteins decreased in proplatelet-producing megakaryocytes, consistent with data showing that protein degradation is necessary for proplatelet formation. Specifically, the centrosome stabilizing proteins Aurora kinase (Aurk) A/B, Tpx2, Cdk1, and Plk1 were decreased in proplatelet-producing MKs. Furthermore, inhibition of AurkA and Plk1, but not Cdk1, significantly inhibited proplatelet formation in vitro over 83%. Conclusions: We hypothesize that proplatelet formation is triggered by centrosome destabilization and disassembly, and that the ubiquitin-proteasome pathway plays a crucial role in this transformation. Specifically, regulation of the AurkA/Plk1/Tpx2 pathway may be key in centrosome integrity and initiation of proplatelet formation. Determination of the mechanism by which the ubiquitin-proteasome pathway regulates the centrosome and facilitates proplatelet formation will allow us to design better strategies to target and reverse thrombocytopenia.

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The Ubiquitin Proteasome Pathway from Bench to Bedside

Hematology ◽

10.1182/asheducation-2005.1.220 ◽

2005 ◽

Vol 2005 (1) ◽

pp. 220-225 ◽

Cited By ~ 18

Author(s):

Robert Z. Orlowski

Keyword(s):

Phase I ◽

Hematological Malignancies ◽

Expression Profiles ◽

Proteasome Inhibitors ◽

Rational Approach ◽

Significant Activity ◽

Ubiquitin Proteasome Pathway ◽

Gene And Protein Expression ◽

Ubiquitin Proteasome ◽

Proteasome Pathway

Abstract The validation of the ubiquitin-proteasome pathway as a target for therapy of hematological malignancies stands out as one salient example of the ability to translate laboratory-based findings from the bench to the bedside. Preclinical studies showed that proteasome inhibitors had significant activity against models of non-Hodgkin lymphoma and multiple myeloma, and identified some of the relevant mechanisms of action. These led to phase I through III trials of the first clinically available proteasome inhibitor, bortezomib, which confirmed its activity as a single agent in these diseases. Modulation of proteasome function was then found to be a rational approach to achieve both chemosensitization in vitro and in vivo, as well as to overcome chemotherapy resistance. Based on these findings, first-generation bortezomib-based regimens incorporating traditional chemotherapeutics such as alkylating agents, anthracyclines, immunomodulatory agents, or steroids have been evaluated, and many show promise of enhanced clinical anti-tumor efficacy. Further studies of the pro-and anti-apoptotic actions of proteasome inhibitors, and of their effects on gene and protein expression profiles, suggest that novel agents, such as those targeting the heat shock protein pathways, are exciting candidates for incorporation into these combinations. Phase I trials to test these concepts are just beginning, but have already shown some encouraging results. Finally, novel proteasome inhibitors are being developed with unique properties that may also have therapeutic applications. Taken together, these studies demonstrate the power of rational drug design and development to provide novel, effective therapies for patients with hematological malignancies.

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Ubiquitination and Ubiquitin-Like Modifications in Multiple Myeloma: Biology and Therapy

Cancers ◽

10.3390/cancers12123764 ◽

2020 ◽

Vol 12 (12) ◽

pp. 3764

Author(s):

Matthias Wirth ◽

Markus Schick ◽

Ulrich Keller ◽

Jan Krönke

Keyword(s):

Multiple Myeloma ◽

Translational Regulation ◽

Proteasome Inhibitors ◽

Ubiquitin Proteasome System ◽

Organ Damage ◽

Post Translational Modifications ◽

Damage Repair ◽

Ubiquitin Proteasome ◽

New Treatments ◽

Effective Drugs

Multiple myeloma is a genetically heterogeneous plasma cell malignancy characterized by organ damage and a massive production of (in-)complete monoclonal antibodies. Coping with protein homeostasis and post-translational regulation is therefore essential for multiple myeloma cells to survive. Furthermore, post-translational modifications such as ubiquitination and SUMOylation play key roles in essential pathways in multiple myeloma, including NFκB signaling, epigenetic regulation, as well as DNA damage repair. Drugs modulating the ubiquitin–proteasome system, such as proteasome inhibitors and thalidomide analogs, are approved and highly effective drugs in multiple myeloma. In this review, we focus on ubiquitin and ubiquitin-like modifications in the biology and current developments of new treatments for multiple myeloma.

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Activity of Circulating Proteasomes Correlates with Clinical Behavior in Patients with Chronic Myeloid Leukemia.

Blood ◽

10.1182/blood.v110.11.4546.4546 ◽

2007 ◽

Vol 110 (11) ◽

pp. 4546-4546

Author(s):

Wanlong Ma ◽

Hagop Kantarjian ◽

Amber Donahue ◽

Xi Zhang ◽

Susan O’Brien ◽

...

Keyword(s):

Chronic Myeloid Leukemia ◽

Healthy Volunteers ◽

Myeloid Leukemia ◽

Proteasome Inhibitors ◽

Continuous Variable ◽

Peptidase Activity ◽

Clinical Behavior ◽

Ubiquitin Proteasome ◽

Important Regulator ◽

Proteasome Pathway

Abstract The ubiquitin-proteasome pathway is implicated in the pathogenesis of many malignancies and is an important regulator of cell proliferation, apoptosis, DNA repair, and the stress response. Free circulating proteasomes have been reported in the plasma and sera of cancer patients. We measured proteasome peptidase activity in the plasma of patients with chronic myeloid leukemia (CML) and correlated these findings with clinical behaviour. Plasma samples from apparently healthy volunteers (n = 92) and patients in the chronic (n = 104) or accelerated/blast phase (n = 56) of CML were analysed with fluorogenic kinetic assays. Using peptide-AMC (7-amino-4-methylcoumaran) substrates, we measured the three reported proteasome enzymatic activities: chymotrypsin-like (Ch-L), trypsin-like (Tr-L), and caspase-like (Cas-L). All proteasome activities were significantly higher in CML patients than in healthy volunteers. Extensive characterization of proteasome activities revealed correlations between levels or ratios of specific peptidase activities and disease phase, progression, aggressiveness, and survival. High Ch-L activity correlated with shorter survival in both CP (P=0.037) and Acc/Bl phase (P=0.047). Patients in CP and a ratio of Cas-L: Tr-L activity >1.48 had significantly shorter survival (P=0.03). Cas-L: Tr-L activity ratio was predictor of survival in Acc/Bl patients as a continuous variable. These findings suggest that proteasome activity in the plasma of CML patients reflects disease activity and can be used as a biomarker for predicting clinical behavior. Studies exploring the role of proteasome inhibitors in CML are therefore warranted.

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Discovery of Therapeutic Deubiquitylase Effector Molecules

CrossRef Listing of Deleted DOIs ◽

10.1177/1087057114527312 ◽

2014 ◽

Vol 19 (7) ◽

pp. 989-999 ◽

Cited By ~ 7

Author(s):

B. Nicholson ◽

Suresh Kumar ◽

S. Agarwal ◽

M. J. Eddins ◽

J. G. Marblestone ◽

...

Keyword(s):

High Throughput Screening ◽

Proteasome Inhibitors ◽

Therapeutic Targets ◽

Cysteine Proteases ◽

Preclinical Development ◽

E3 Ligases ◽

The Past ◽

Novel Drugs ◽

Ubiquitin Proteasome ◽

Proteasome Pathway

The approval of proteasome inhibitors bortezomib and carfilzomib and the E3 ligase antagonist thalidomide and its analogs, lenalidomide and pomalidomide, validates the ubiquitin–proteasome pathway as a source of novel drugs for treating cancer and, potentially, a variety of devastating illnesses, including inflammation, cardiovascular disease, and neurodegenerative disease. All elements of this critical regulatory pathway—the proteasome itself, E3 ligases (which conjugate ubiquitin to target proteins), and deubiquitylating enzymes (which deconjugate ubiquitin, reversing ligase action)—are potential therapeutic targets, and all have been worked on extensively during the past decade. No deubiquitylase inhibitors or activators have yet progressed to clinical trial, however, despite compelling target validation and several years of high-throughput screening and preclinical development of hits by numerous pharmaceutical companies, biotechnology organizations, and academic groups. The appropriateness of deubiquitylases as therapeutic targets in many disease areas is reviewed, followed by evidence that selective inhibitors of these cysteine proteases can be discovered. Because the lack of progress in drug-discovery efforts with deubiquitylases suggests a need for improved discovery methodologies, currently available platforms and strategies are analyzed, and improved or completely novel, unrelated approaches are considered in terms of their likelihood of producing clinically viable effectors of deubiquitylases.

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Potent activity of carfilzomib, a novel, irreversible inhibitor of the ubiquitin-proteasome pathway, against preclinical models of multiple myeloma

Blood ◽

10.1182/blood-2007-01-065888 ◽

2007 ◽

Vol 110 (9) ◽

pp. 3281-3290 ◽

Cited By ~ 470

Author(s):

Deborah J. Kuhn ◽

Qing Chen ◽

Peter M. Voorhees ◽

John S. Strader ◽

Kevin D. Shenk ◽

...

Keyword(s):

Multiple Myeloma ◽

Cell Death ◽

Proteasome Inhibitor ◽

Hematologic Malignancies ◽

Irreversible Inhibitor ◽

Inhibition Of Proliferation ◽

Mitochondrial Membrane Depolarization ◽

Dependent Inhibition ◽

Ubiquitin Proteasome ◽

Proteasome Pathway

AbstractThe proteasome has emerged as an important target for cancer therapy with the approval of bortezomib, a first-in-class, reversible proteasome inhibitor, for relapsed/refractory multiple myeloma (MM). However, many patients have disease that does not respond to bortezomib, whereas others develop resistance, suggesting the need for other inhibitors with enhanced activity. We therefore evaluated a novel, irreversible, epoxomicin-related proteasome inhibitor, carfilzomib. In models of MM, this agent potently bound and specifically inhibited the chymotrypsin-like proteasome and immunoproteasome activities, resulting in accumulation of ubiquitinated substrates. Carfilzomib induced a dose- and time-dependent inhibition of proliferation, ultimately leading to apoptosis. Programmed cell death was associated with activation of c-Jun-N-terminal kinase, mitochondrial membrane depolarization, release of cytochrome c, and activation of both intrinsic and extrinsic caspase pathways. This agent also inhibited proliferation and activated apoptosis in patient-derived MM cells and neoplastic cells from patients with other hematologic malignancies. Importantly, carfilzomib showed increased efficacy compared with bortezomib and was active against bortezomib-resistant MM cell lines and samples from patients with clinical bortezomib resistance. Carfilzomib also overcame resistance to other conventional agents and acted synergistically with dexamethasone to enhance cell death. Taken together, these data provide a rationale for the clinical evaluation of carfilzomib in MM.

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Proteasome Inhibitors Block a Late Step in Lysosomal Transport of Selected Membrane but not Soluble Proteins

Molecular Biology of the Cell ◽

10.1091/mbc.12.8.2556 ◽

2001 ◽

Vol 12 (8) ◽

pp. 2556-2566 ◽

Cited By ~ 84

Author(s):

Peter van Kerkhof ◽

Cristina M. Alves dos Santos ◽

Martin Sachse ◽

Judith Klumperman ◽

Guojun Bu ◽

...

Keyword(s):

Membrane Proteins ◽

Proteasome Inhibitors ◽

Endocytic Pathway ◽

Endosomal Sorting ◽

Ubiquitin Proteasome Pathway ◽

Late Step ◽

Ubiquitin Proteasome ◽

Proteasome Pathway ◽

Lysosomal Transport

The ubiquitin-proteasome pathway acts as a regulator of the endocytosis of selected membrane proteins. Recent evidence suggests that it may also function in the intracellular trafficking of membrane proteins. In this study, several models were used to address the role of the ubiquitin-proteasome pathway in sorting of internalized proteins to the lysosome. We found that lysosomal degradation of ligands, which remain bound to their receptors within the endocytic pathway, is blocked in the presence of specific proteasome inhibitors. In contrast, a ligand that dissociates from its receptor upon endosome acidification is degraded under the same conditions. Quantitative electron microscopy showed that neither the uptake nor the overall distribution of the endocytic marker bovine serum albumin-gold is substantially altered in the presence of a proteasome inhibitor. The data suggest that the ubiquitin-proteasome pathway is involved in an endosomal sorting step of selected membrane proteins to lysosomes, thereby providing a mechanism for regulated degradation.

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