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

Cancers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3764
Author(s):  
Matthias Wirth ◽  
Markus Schick ◽  
Ulrich Keller ◽  
Jan Krönke

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.

Cancers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 2235
Author(s):  
Jonathan J. Morgan ◽  
Lisa J. Crawford

Faithful DNA replication during cellular division is essential to maintain genome stability and cells have developed a sophisticated network of regulatory systems to ensure its integrity. Disruption of these control mechanisms can lead to loss of genomic stability, a key hallmark of cancer. Ubiquitination is one of the most abundant regulatory post-translational modifications and plays a pivotal role in controlling replication progression, repair of DNA and genome stability. Dysregulation of the ubiquitin proteasome system (UPS) can contribute to the initiation and progression of neoplastic transformation. In this review we provide an overview of the UPS and summarize its involvement in replication and replicative stress, along with DNA damage repair. Finally, we discuss how the UPS presents as an emerging source for novel therapeutic interventions aimed at targeting genomic instability, which could be utilized in the treatment and management of cancer.


2020 ◽  
Vol 10 (12) ◽  
Author(s):  
Yanyan Gu ◽  
Benjamin G. Barwick ◽  
Mala Shanmugam ◽  
Craig C. Hofmeister ◽  
Jonathan Kaufman ◽  
...  

AbstractProtein homeostasis is critical for maintaining eukaryotic cell function as well as responses to intrinsic and extrinsic stress. The proteasome is a major portion of the proteolytic machinery in mammalian cells and plays an important role in protein homeostasis. Multiple myeloma (MM) is a plasma cell malignancy with high production of immunoglobulins and is especially sensitive to treatments that impact protein catabolism. Therapeutic agents such as proteasome inhibitors have demonstrated significant benefit for myeloma patients in all treatment phases. Here, we demonstrate that the 11S proteasome activator PA28α is upregulated in MM cells and is key for myeloma cell growth and proliferation. PA28α also regulates MM cell sensitivity to proteasome inhibitors. Downregulation of PA28α inhibits both proteasomal load and activity, resulting in a change in protein homeostasis less dependent on the proteasome and leads to cell resistance to proteasome inhibitors. Thus, our findings suggest an important role of PA28α in MM biology, and also provides a new approach for targeting the ubiquitin-proteasome system and ultimately sensitivity to proteasome inhibitors.


2020 ◽  
Vol 318 (3) ◽  
pp. C451-C462 ◽  
Author(s):  
Paula Saavedra-García ◽  
Francesca Martini ◽  
Holger W. Auner

Cellular protein homeostasis (proteostasis) depends on the controlled degradation of proteins that are damaged or no longer required by the ubiquitin-proteasome system (UPS). The 26S proteasome is the principal executer of substrate-specific proteolysis in eukaryotic cells and regulates a myriad of cellular functions. Proteasome inhibitors were initially developed as chemical tools to study proteasomal function but rapidly became widely used anticancer drugs that are now used at all stages of treatment for the bone marrow cancer multiple myeloma (MM). Here, we review the mechanisms of action of proteasome inhibitors that underlie their preferential toxicity to MM cells, focusing on endoplasmic reticulum stress, depletion of amino acids, and effects on glucose and lipid metabolism. We also discuss mechanisms of resistance to proteasome inhibition such as autophagy and metabolic rewiring and what lessons we may learn from the success and failure of proteasome inhibition in MM for treating other cancers with proteostasis-targeting drugs.


2005 ◽  
Vol 41 ◽  
pp. 205-218
Author(s):  
Constantine S. Mitsiades ◽  
Nicholas Mitsiades ◽  
Teru Hideshima ◽  
Paul G. Richardson ◽  
Kenneth C. Anderson

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.


2007 ◽  
Vol 18 (11) ◽  
pp. 4279-4291 ◽  
Author(s):  
Sean M. Kelly ◽  
Judy K. VanSlyke ◽  
Linda S. Musil

ER-associated, ubiquitin-proteasome system (UPS)-mediated degradation of the wild-type (WT) gap junction protein connexin32 (Cx32) is inhibited by mild forms of cytosolic stress at a step before its dislocation into the cytosol. We show that the same conditions (a 30-min, 42°C heat shock or oxidative stress induced by arsenite) also reduce the endoplasmic reticulum (ER)-associated turnover of disease-causing mutants of Cx32 and the cystic fibrosis transmembrane conductance regulator (CFTR), as well as that of WT CFTR and unassembled Ig light chain. Stress-stabilized WT Cx32 and CFTR, but not the mutant/unassembled proteins examined, could traverse the secretory pathway. Heat shock also slowed the otherwise rapid UPS-mediated turnover of the cytosolic proteins myoD and GFPu, but not the degradation of an ubiquitination-independent construct (GFP-ODC) closely related to the latter. Analysis of mutant Cx32 from cells exposed to proteasome inhibitors and/or cytosolic stress indicated that stress reduces degradation at the level of substrate polyubiquitination. These findings reveal a new link between the cytosolic stress-induced heat shock response, ER-associated degradation, and polyubiquitination. Stress-denatured proteins may titer a limiting component of the ubiquitination machinery away from pre-existing UPS substrates, thereby sparing the latter from degradation.


2010 ◽  
Vol 84 (18) ◽  
pp. 9625-9631 ◽  
Author(s):  
Ivy Widjaja ◽  
Erik de Vries ◽  
Donna M. Tscherne ◽  
Adolfo García-Sastre ◽  
Peter J. M. Rottier ◽  
...  

ABSTRACT We have demonstrated that influenza A virus (IAV) RNA synthesis depends on the ubiquitin-proteasome system. IAV replication was reduced both by proteasome inhibitors and in E36ts20 cells, which contain the thermolabile ubiquitin-activating enzyme E1. While virus entry was not affected in E36ts20 cells, the proteasome inhibitor MG132 retained viral particles in the cytoplasm. Addition-removal experiments of MG132 in combination with bafilomycin A1, a well-established inhibitor of IAV entry and fusion, showed that MG132 affected IAV infection at a postfusion step. This was confirmed by the lack of inhibition of IAV entry by proteasome inhibitors in a virus-like particle fusion assay.


2021 ◽  
Vol 22 (24) ◽  
pp. 13309
Author(s):  
Magdalena Staszczak

The ubiquitin–proteasome system (UPS) is the major non-lysosomal pathway responsible for regulated degradation of intracellular proteins in eukaryotes. As the principal proteolytic pathway in the cytosol and the nucleus, the UPS serves two main functions: the quality control function (i.e., removal of damaged, misfolded, and functionally incompetent proteins) and a major regulatory function (i.e., targeted degradation of a variety of short-lived regulatory proteins involved in cell cycle control, signal transduction cascades, and regulation of gene expression and metabolic pathways). Aberrations in the UPS are implicated in numerous human pathologies such as cancer, neurodegenerative disorders, autoimmunity, inflammation, or infectious diseases. Therefore, the UPS has become an attractive target for drug discovery and development. For the past two decades, much research has been focused on identifying and developing compounds that target specific components of the UPS. Considerable effort has been devoted to the development of both second-generation proteasome inhibitors and inhibitors of ubiquitinating/deubiquitinating enzymes. With the feature of unique structure and bioactivity, secondary metabolites (natural products) serve as the lead compounds in the development of new therapeutic drugs. This review, for the first time, summarizes fungal secondary metabolites found to act as inhibitors of the UPS components.


2019 ◽  
Author(s):  
Esther Fernández-Simón ◽  
Cinta Lleixà ◽  
Xavier Suarez-Calvet ◽  
Jordi Diaz-Manera ◽  
Isabel Illa ◽  
...  

Abstract Background: Dysferlin is a type-II transmembrane protein and the causative gene of dysferlinopathies, which are characterized by absence or marked reduction in dysferlin protein and muscle weakness. Dysferlin is implicated in vesicle fusion, trafficking, and membrane repair. The muscle biopsy of patients with dysferlinopathy is characterized by the presence of inflammatory infiltrates. Release of thrombospondin-1 (TSP-1) by dysferlin deficient muscle has been reported as a possible factor of the inflammation observed in the muscle of both human and mouse models of dysferlinopathy. It has also been reported that treatment with vitamin D3 enhances dysferlin expression. The ubiquitin-proteasome system recognizes and removes proteins that fail to fold or assemble properly and previous studies suggest that its inhibition could have a therapeutic implication in muscle dystrophies. Here we assessed whether inhibition of the ubiquitin proteasome system prevented degradation of dysferlin in immortalized myoblasts from a patient carrying two missense mutationsMethods: Dysferlin deficient myotubes were treated with EB1089, a vitamin D3 analog, oprozomib and ixazomib to assess proteasome inhibition. Western blot was performed to analyze the effect of the different treatments on the recovery of dysferlin and myogenin expression. TSP-1 was quantified using Enzyme Linked Immunosorbent Assay to analyze the effect of these drugs on its release.A membrane repair assay was designed to assess the ability of treated myotubes to recover after membrane injury. Data were analyzed using a one-way ANOVA test followed by by Tukey post hoc test and analysis of variance. Ap≤0.05 was considered statistically significant. Results : Treatment with proteasome inhibitors and EB1089 resulted in a slight increase of dysferlin expression which was accompanied by a low increase of myogenin expression. Also, EB1089 and proteasome inhibitors reduced the release of TSP-1 in myotubes from a dysferlinopathy patient. However, the increase of dysferlin had no effect on the repair of muscle membrane after injury. Conclusions: Our findings indicate that the ubiquitin-proteasome system might not be the main mechanism of mutant dysferlin degradation. However, its inhibition could help to improve muscle inflammation by reducing TSP-1 release.


2021 ◽  
Vol 11 ◽  
Author(s):  
Shansa Pranami E. Jayaweera ◽  
Sacheela Prasadi Wanigasinghe Kanakanamge ◽  
Dharshika Rajalingam ◽  
Gayathri N. Silva

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.


Author(s):  
Chengjun Cao ◽  
Chaoyang Xue

Ubiquitin-proteasome mediated protein turnover is an important regulatory mechanism of cellular function in eukaryotes. Extensive studies have linked the ubiquitin-proteasome system (UPS) to human diseases, and an array of proteasome inhibitors have been successfully developed for cancer therapy. Although still an emerging field, research on UPS regulation of fungal development and virulence has been rapidly advancing and has generated considerable excitement in its potential as a target for novel drugs. In this review, we summarize UPS composition and regulatory function in pathogenic fungi, especially in stress responses, host adaption, and fungal pathogenesis. Emphasis will be given to UPS regulation of pathogenic factors that are important for fungal pathogenesis. We also discuss future potential therapeutic strategies for fungal infections based on targeting UPS pathways.


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