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1.
Cancer Treat Rev ; 82: 101929, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31770695

RESUMO

Autologous stem cell transplantation (ASCT) has been the mainstay of multiple myeloma (MM) treatment for approximately 30 years. Although the continuous introduction of novel agents in the armamentarium against MM has questioned its value, ASCT remains a backbone treatment for fit MM patients. However, there is no unanimous approach for several aspects including the positioning of ASCT in the therapeutic algorithm either upfront or following the first relapse, the need for single or tandem ASCT, as well as the role of ASCT as salvage therapy. Furthermore, the anti-CD38 monoclonal antibodies along with the next generation proteasome inhibitors and immunomodulatory drugs provide a platform for optimizing the induction and consolidation/maintenance regimens. In this review, we present current data pertaining to all aspects of ASCT in MM, whereas we highlight the open issues that should be addressed in the design of future clinical trials in the field.


Assuntos
Mieloma Múltiplo/terapia , Administração dos Cuidados ao Paciente , Transplante de Células-Tronco/métodos , Antineoplásicos Imunológicos/farmacologia , Humanos , Administração dos Cuidados ao Paciente/métodos , Administração dos Cuidados ao Paciente/normas , Inibidores de Proteassoma/farmacologia , Transplante Autólogo
2.
Virol Sin ; 34(5): 572-582, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31637631

RESUMO

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging hemorrhagic fever disease caused by SFTSV, a newly discovered phlebovirus that is named after the disease. Currently, no effective vaccines or drugs are available for use against SFTSV infection, as our understanding of the viral pathogenesis is limited. Bortezomib (PS-341), a dipeptide-boronic acid analog, is the first clinically approved proteasome inhibitor for use in humans. In this study, the antiviral efficacy of PS-341 against SFTSV infection was tested in human embryonic kidney HEK293T (293T) cells. We employed four different assays to analyze the antiviral ability of PS-341 and determined that PS-341 inhibited the proliferation of SFTSV in 293T cells under various treatment conditions. Although PS-341 did not affect the virus absorption, PS-341 treatment within a non-toxic concentration range resulted in a significant reduction of progeny viral titers in infected cells. Dual-luciferase reporter assays and Western blot analysis revealed that PS-341 could reverse the SFTSV-encoded non-structural protein (NS) mediated degradation of retinoic acid-inducible gene-1 (RIG-I), thereby antagonizing the inhibitory effect of NSs on interferons and blocking virus replication. In addition, we observed that inhibition of apoptosis promotes virus replication. These results indicate that targeting of cellular interferon pathways and apoptosis during acute infection might serve as the bases of future therapeutics for the treatment of SFTSV infections.


Assuntos
Antivirais/farmacologia , Bortezomib/farmacologia , Phlebovirus/efeitos dos fármacos , Inibidores de Proteassoma/farmacologia , Apoptose , Células HEK293 , Humanos , Transdução de Sinais , Carga Viral , Replicação Viral/efeitos dos fármacos
3.
Medicine (Baltimore) ; 98(39): e17148, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31574818

RESUMO

RATIONALE: Thrombotic microangiopathy (TMA) is a group of clinical syndromes characterized by excessive platelet activation and endothelial injury that leads to acute or chronic microvascular obliteration by intimal mucoid and fibrous thickening, with or without associated thrombi. It frequently involves the kidney but may involve any organ or system at variable frequencies depending on the underlying etiology. Among its numerous causes, drug toxicities and complement regulation abnormalities stand out as some of the most common. A more recently described association is with monoclonal gammopathy. Lung involvement by TMA is infrequent, but has been described in Cobalamin C deficiency and post stem-cell transplantation TMA. PATIENT CONCERNS: This is the case of a patient with smoldering myeloma who received proteasome-inhibitor therapy due to retinopathy and developed acute renal failure within one week of therapy initiation. DIAGNOSES: A renal biopsy showed thrombotic microangiopathy. At the time, mild pulmonary hypertension was also noted and presumed to be idiopathic. INTERVENTIONS: Given the known association of proteasome-inhibitor therapy with thrombotic microangiopathy, Bortezomib was discontinued and dialysis was initiated. OUTCOMES: Drug withdrawal failed to prevent disease progression and development of end-stage renal disease, as well as severe pulmonary hypertension that eventually lead to the patient's death. LESSONS: To our knowledge, this is the first reported case of pulmonary involvement by TMA associated with monoclonal gammopathy which appears to have been triggered by proteasome-inhibitor therapy. Clinicians should be aware of this possibility to allow for more prompt recognition of pulmonary hypertension as a potential manifestation of monoclonal gammopathy-associated TMA, especially in patients also receiving proteasome-inhibitors, so that treatment aiming to slow disease progression can be instituted.


Assuntos
Lesão Renal Aguda/induzido quimicamente , Hipertensão Pulmonar/induzido quimicamente , Inibidores de Proteassoma/efeitos adversos , Mieloma Múltiplo Latente/tratamento farmacológico , Microangiopatias Trombóticas/induzido quimicamente , Autopsia , Biópsia , Evolução Fatal , Feminino , Humanos , Rim/efeitos dos fármacos , Rim/patologia , Pulmão/efeitos dos fármacos , Pessoa de Meia-Idade , Paraproteinemias/complicações , Mieloma Múltiplo Latente/etiologia
4.
Rinsho Ketsueki ; 60(9): 1257-1264, 2019.
Artigo em Japonês | MEDLINE | ID: mdl-31597851

RESUMO

The introduction of proteasome inhibitors (PIs), such as bortezomib (BTZ), and immunomodulatory drugs (IMiDs), including thalidomide (THAL) and lenalidomide (LEN), as first-line therapies in multiple myeloma (MM) has markedly improved the clinical outcomes of patients. However, MM remains incurable, and most patients eventually relapse. Moreover, prognosis is poor in patients who exhibit resistance to BTZ or LEN, and novel therapeutic approaches for such patients are urgently needed. Currently, the following six drugs are available for use in relapsed patients: second generation PIs (carfilzomib and ixazomib), an IMiD (pomalidomide), a histone deacetylase (HDAC) inhibitor (panobinostat), and two monoclonal antibodies (elotuzumab and daratumumab). The choice of treatment should be individualized based on certain factors, such as age, presence of comorbidities, frailty, cytogenetic risk, efficacy and toxicity of prior treatments, and the duration of the previous response. A course of triplet therapy containing two novel agents along with DEX is recommended, on first relapse, in fit and healthy patients, whereas doublet therapy is preferred for unfit or frail patients. Retreatment of relapsed/refractory MM (RRMM) with monoclonal antibodies and IMiDs is promising because these drugs have immunostimulatory effects. In addition, novel agents, including an anti-BCMA antibody-drug conjugate, are being studied. Clinical trials are needed to define the optimal treatment strategy for RRMM.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Inibidores de Histona Desacetilases/uso terapêutico , Mieloma Múltiplo/terapia , Inibidores de Proteassoma/uso terapêutico , Humanos , Recidiva Local de Neoplasia
5.
Eur J Med Chem ; 182: 111646, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31521028

RESUMO

The immunoproteasome, a specialized form of proteasome, is mainly expressed in lymphocytes and monocytes of jawed vertebrates and responsible for the generation of antigenic peptides for cell-mediated immunity. Overexpression of immunoproteasome have been detected in a wide range of diseases including malignancies, autoimmune and inflammatory diseases. Following the successful approval of constitutive proteasome inhibitors bortezomib, carfilzomib and Ixazomib, and with the clarification of immunoproteasome crystal structure and functions, a variety of immunoproteasome inhibitors were discovered or rationally developed. Not only the inhibitory activities, the selectivities for immunoproteasome over constitutive proteasome are essential for the clinical potential of these analogues, which has been validated by the clinical evaluation of immunoproteasome-selective inhibitor KZR-616 for the treatment of systemic lupus erythematosus. In this review, structure, function as well as the current developments of various inhibitors against immunoproteasome are going to be summarized, which help to fully understand the target for drug discovery.


Assuntos
Antineoplásicos/farmacologia , Doenças Autoimunes/tratamento farmacológico , Neoplasias Hematológicas/tratamento farmacológico , Complexo de Endopeptidases do Proteassoma/metabolismo , Inibidores de Proteassoma/farmacologia , Animais , Antineoplásicos/química , Doenças Autoimunes/metabolismo , Compostos de Boro/química , Compostos de Boro/farmacologia , Bortezomib/química , Bortezomib/farmacologia , Glicina/análogos & derivados , Glicina/química , Glicina/farmacologia , Neoplasias Hematológicas/metabolismo , Humanos , Oligopeptídeos/química , Oligopeptídeos/farmacologia , Inibidores de Proteassoma/química
6.
Int J Mol Sci ; 20(18)2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31514384

RESUMO

Alpha-synuclein (α-Syn) can misfold and aggregate, causing the degeneration of dopaminergic neurons, as seen in Parkinson's disease (PD). We recently demonstrated that DNAJB6, a co-chaperone found in Lewy bodies (LB), suppresses the aggregation of α-Syn in cells and in vitro. In this study, we compared the capacities of DNAJB1 and DNAJB6 to suppress the seeded α-Syn aggregation in HEK293 cells expressing α-Syn tagged with cyan fluorescent protein (CFP) or yellow fluorescent protein (YFP). The aggregation of α-Syn was seeded by the transfection of the cells with recombinant α-Syn pre-formed fibrils (PFFs), following the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas9-mediated knockout (KO) of these two genes, respectively. We quantified the α-Syn aggregation by fluorescence microscopy and fluorescence resonance energy transfer (FRET) analysis. We detected significantly more aggregates in the DNAJB6 KO cells compared with the parental cells, whereas the DNAJB1 KO had no effect on the α-Syn aggregation. This is the first evidence that DNAJB6 can suppress α-Syn aggregation, induced by exogenous α-Syn seeds, in cells. Next, we explored whether this mechanism could be dependent on protein degradation pathways. We observed that the increase in the α-Syn PFF-induced aggregation in the DNAJB6 KO cells compared with the parental cells was strongly diminished upon the incubation of the cells with the proteasomal inhibitor MG132. These results consolidate that DNAJB6 is a suppressor of α-Syn aggregation, and suggest that DNAJB6 may target misfolded and/or aggregated α-Syn for proteasomal degradation.


Assuntos
Proteínas de Choque Térmico HSP40/metabolismo , Chaperonas Moleculares/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Agregados Proteicos , alfa-Sinucleína/metabolismo , Células HEK293 , Humanos , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismo , Inibidores de Proteassoma/farmacologia
7.
Bratisl Lek Listy ; 120(9): 646-649, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31475547

RESUMO

BACKGROUND: It has been demonstrated that proteasome inhibitors might be potential anticancer drugs. The copper complexes can be used as specific proteasome inhibitors in tumor cells able to induce apoptosis by the ubiquitin-proteasome pathway. The goal of our study was to test the cytotoxic and proteasome inhibitory effects of five Schiff base Cu(II) complexes - [Cu2(sal-D,L-glu)2(isoquinoline)2] . 2C2H5OH (1), [Cu(sal-5-met-L-glu)(H2O)].H2O (2), [Cu(ethanol)2(imidazole)4][Cu2(sal-D,L-glu)2(imidazole)2] (3), [Cu(sal-D,L-glu)(2-methylimidazole)] (4) on human lung carcinoma cells A549, cervix carcinoma cells HeLa and glioblastoma cells U-118MG. MATERIAL AND METHODS: For the cytotoxic analysis we used MTT test and for monitoring the proteasome inhibition western blot analysis. RESULTS: We have observed different cytotoxic effects of tested complexes on human cancer cells depending on the ligand present in their structure. Cu(II) complexes 4 and 5 were the most effective against A549 cells; all complexes were cytotoxic against HeLa cells and the complex 4 was the most effective against U-118MG. Moreover, we have detected the inhibition of the proteasome activity in human cancer cells A549 by Cu(II) complexes 1, 2 and 4 at IC50 concentration. CONCLUSION: Results of our study suggest that isoquinoline- and imidazole-based copper complexes could be used as inhibitors of the proteasome system in cancer cells A549 (Tab. 1, Fig. 1, Ref. 26).


Assuntos
Cobre/farmacologia , Inibidores de Proteassoma/farmacologia , Bases de Schiff/farmacologia , Células A549 , Antineoplásicos/farmacologia , Apoptose , Complexos de Coordenação/farmacologia , Células HeLa , Humanos , Complexo de Endopeptidases do Proteassoma
8.
Int J Mol Sci ; 20(14)2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31295808

RESUMO

Proteasome inhibitors have been actively tested as potential anticancer drugs and in the treatment of inflammatory and autoimmune diseases. Unfortunately, cells adapt to survive in the presence of proteasome inhibitors activating a variety of cell responses that explain why these therapies have not fulfilled their expected results. In addition, all proteasome inhibitors tested and approved by the FDA have caused a variety of side effects in humans. Here, we describe the different types of proteasome complexes found within cells and the variety of regulators proteins that can modulate their activities, including those that are upregulated in the context of inflammatory processes. We also summarize the adaptive cellular responses activated during proteasome inhibition with special emphasis on the activation of the Autophagic-Lysosomal Pathway (ALP), proteaphagy, p62/SQSTM1 enriched-inclusion bodies, and proteasome biogenesis dependent on Nrf1 and Nrf2 transcription factors. Moreover, we discuss the role of IRE1 and PERK sensors in ALP activation during ER stress and the involvement of two deubiquitinases, Rpn11 and USP14, in these processes. Finally, we discuss the aspects that should be currently considered in the development of novel strategies that use proteasome activity as a therapeutic target for the treatment of human diseases.


Assuntos
Complexo de Endopeptidases do Proteassoma/metabolismo , Inibidores de Proteassoma/farmacologia , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Autofagia/efeitos dos fármacos , Estresse do Retículo Endoplasmático , Humanos , Imunomodulação/efeitos dos fármacos , Lisossomos/metabolismo , Neoplasias/tratamento farmacológico , Neoplasias/etiologia , Neoplasias/metabolismo , Neoplasias/patologia , Inibidores de Proteassoma/uso terapêutico , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Resposta a Proteínas não Dobradas
9.
Transplant Proc ; 51(6): 1732-1738, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31301858

RESUMO

Plasma cell-rich acute rejection (PCAR) and antibody-mediated rejection (ABMR), for which a standard treatment has not yet been established, are associated with poor graft survival after kidney transplantation. Here, we report a case series of 3 Japanese patients diagnosed with PCAR accompanied by ABMR. Steroid pulse therapy and rabbit antithymocyte globulin, plasma exchange, intravenous immunoglobulin, and rituximab therapies were sequentially performed in the first case. A graft biopsy after each treatment showed that plasma cell infiltration persisted. Five months after the initiation of rejection therapy, the patient was subjected to bortezomib therapy, which led to the partial elimination of plasma cells from the graft. However, the graft function gradually deteriorated, and hemodialysis treatment was warranted. In the other 2 cases, the patients received the same combination of therapy including bortezomib within a short period. Graft biopsies performed subsequently showed a marked decrease in the number of infiltrated plasma cells, and stabilization of renal graft function was achieved in both cases. Bortezomib, which targets plasma cells, is a potent drug that eliminates infiltrated plasma cells from the graft in PCAR. Thus, in addition to conventional therapy comprising plasma exchange, intravenous immunoglobulin, and rituximab against ABMR, bortezomib may be necessary to administer without any delay to control PCAR.


Assuntos
Bortezomib/uso terapêutico , Terapia Combinada/métodos , Rejeição de Enxerto/tratamento farmacológico , Plasmócitos/efeitos dos fármacos , Inibidores de Proteassoma/uso terapêutico , Adolescente , Corticosteroides/administração & dosagem , Pré-Escolar , Feminino , Rejeição de Enxerto/imunologia , Rejeição de Enxerto/patologia , Sobrevivência de Enxerto , Humanos , Imunoglobulinas Intravenosas/administração & dosagem , Transplante de Rim/efeitos adversos , Masculino , Plasmócitos/patologia , Plasmaferese , Estudos Retrospectivos , Rituximab/administração & dosagem , Adulto Jovem
10.
J Enzyme Inhib Med Chem ; 34(1): 1307-1313, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31307247

RESUMO

Proteasome inhibition is a promising strategy for the treatment of multiple myeloma; unfortunately, this disease is often associated with an increasing chemoresistance. One novel approach may be to target the immunoproteasome, a proteasomal isoform mainly present in cells of hematopoietic origin. We investigated the activity of a panel of amides against immunoproteasome core particles as potential agents for the treatment of multiple myeloma (MM). Amide 6 showed an ideal profile since it was able to inhibit both the chymotrypsin-like activities of the immunoproteasome with Ki values of 4.90 µM and 4.39 µM for ß1i and ß5i, respectively, coupled with an EC50 =17.8 µM against MM.1R cells. Compound 6 inhibited also ubiquitinated protein degradation and was able to act on different phases of MM cell cycle reducing the levels of cyclin A/CDK1, cyclin B/CDK1 and cyclin D/CDK4/6 complexes, which turns in cell cycle arrest.


Assuntos
Antineoplásicos/farmacologia , Mieloma Múltiplo/tratamento farmacológico , Complexo de Endopeptidases do Proteassoma/metabolismo , Inibidores de Proteassoma/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Estrutura Molecular , Mieloma Múltiplo/metabolismo , Mieloma Múltiplo/patologia , Inibidores de Proteassoma/síntese química , Inibidores de Proteassoma/química , Relação Estrutura-Atividade
11.
Chem Biol Interact ; 310: 108733, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31276663

RESUMO

Plumbagin (PLB) is an active secondary metabolite extracted from the roots of Plumbago rosea. In this study, we report that plumbagin effectively induces paraptosis by triggering extensive cytoplasmic vacuolation followed by cell death in triple negative breast cancer cells (MDA-MB-231), cervical cancer cells (HeLa) and non-small lung cancer cells (A549) but not in normal lung fibroblast cells (WI-38). The vacuoles originated from the dilation of the endoplasmic reticulum (ER) and were found to be empty. The cell death induced by plumbagin was neither apoptotic nor autophagic. Plumbagin induced ER stress mainly by inhibiting the chymotrypsin-like activity of 26S proteasome as also evident from the accumulation of polyubiquitinated proteins. The vacuolation and cell death were found to be independent of reactive oxygen species generation but was effectively inhibited by thiol antioxidant suggesting that plumbagin could modify the sulfur homeostasis in the cellular milieu. Plumbagin also resulted in a decrease in mitochondrial membrane potential eventually decreasing the ATP production. This is the first study to show that Plumbagin induces paraptosis through proteasome inhibition and disruption of sulfhydryl homeostasis and thus further opens up the lead molecule to potential therapeutic strategies for apoptosis-resistant cancers.


Assuntos
Morte Celular/efeitos dos fármacos , Naftoquinonas/farmacologia , Neoplasias/patologia , Linhagem Celular , Linhagem Celular Tumoral , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Homeostase , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Naftoquinonas/uso terapêutico , Neoplasias/tratamento farmacológico , Inibidores de Proteassoma/farmacologia , Compostos de Sulfidrila/metabolismo , Vacúolos/metabolismo
12.
Phytomedicine ; 63: 153017, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31325684

RESUMO

BACKGROUND: The roots and tubers of several species of the Cyperus genus are used in several parts of the world as foodstuffs and beverages. The genus is rich in several classes of quinones, however their biological properties have not been studied before. PURPOSE: We evaluated the anticancer effect of several benzoquinones isolated from the genus and described their mechanism of action towards cancer cells. METHODS: The most potent molecules were selected according to their effect upon cell viability. The mechanism of cell death was studied by using pharmacological inhibitors of caspases, caspase-3/4/9 activity assays, annexin-V/7-AAD by flow cytometry and intracellular reactive oxygen species and calcium levels through fluorescence spectroscopy. Elucidation of the involvement of distinct branches of the ER stress pathway was pursued by RT-PCR and WB for mRNA and protein expression levels, respectively, as well as pharmacological inhibitors. Proteasome inhibitory activity was assessed by using purified 20S catalytic subunit with the fluorogenic substrate Suc-Leu-Leu-Val-Tyr-AMC. RESULTS: Cytotoxicity studies against cancer cell lines showed that the human gastric cancer cell line AGS was the most susceptible, the most potent molecule, hydroxycyperaquinone, exhibiting an IC50 close to 1 µM. Morphological and biochemical traits suggested that a process of regulated cell death was taking place, which was shown to be intrinsic pathway-independent. Results indicated that benzoquinones exert their toxicity by triggering ER stress, as shown by increased expression of CHOP (mRNA and protein levels), intracellular reactive oxygen species, changes in calcium dynamics and caspase-4 activation. Proteasome inhibition by these molecules is described for the first time. CONCLUSION: Hydroxycyperaquinone is a novel sub-micromolar inhibitor of the 20S catalytic core of the 26S proteasome, causing cell death via IRE1α-independent/PERK-dependent pathways in stomach cancer cells. Its presence in products consumed orally may be of relevance for gastric tumors.


Assuntos
Benzoquinonas/farmacologia , Cyperus/química , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Inibidores de Proteassoma/farmacologia , Neoplasias Gástricas/tratamento farmacológico , Células A549 , Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Caspases/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Endorribonucleases/metabolismo , Humanos , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Sesquiterpenos/farmacologia , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patologia , eIF-2 Quinase/metabolismo
13.
Molecules ; 24(14)2019 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-31315311

RESUMO

Large-scale virtual screening of boronic acid derivatives was performed to identify nonpeptidic covalent inhibitors of the ß5i subunit of the immunoproteasome. A hierarchical virtual screening cascade including noncovalent and covalent docking steps was applied to a virtual library of over 104,000 compounds. Then, 32 virtual hits were selected, out of which five were experimentally confirmed. Biophysical and biochemical tests showed micromolar binding affinity and time-dependent inhibitory potency for two compounds. These results validate the computational protocol that allows the screening of large compound collections. One of the lead-like boronic acid derivatives identified as a covalent immunoproteasome inhibitor is a suitable starting point for chemical optimization.


Assuntos
Ácidos Borônicos/química , Inibidores de Proteassoma/química , Ácidos Borônicos/farmacologia , Simulação por Computador , Avaliação Pré-Clínica de Medicamentos , Modelos Moleculares , Simulação de Acoplamento Molecular , Estrutura Molecular , Inibidores de Proteassoma/farmacologia , Relação Estrutura-Atividade
14.
PLoS One ; 14(5): e0217945, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31150519

RESUMO

Chemical proteasome inhibition has been a valuable animal model of neurodegeneration to uncover roles for the ubiquitin-proteasome system in the central nervous system. However, little is known about the effects of chemical proteasome inhibitors on retinal integrity. Therefore, we characterized the effects of structurally different chemical proteasome inhibitors on the retinal morphology and the mechanisms of their action in the normal adult rat eyes. Intravitreal injection of MG-262 and other proteasome inhibitors led to inner retinal degeneration. MG-262-induced inner retinal degeneration was accompanied by reduced proteasome activity, increased poly-ubiquitinated protein levels, and increased positive immunostaining of ubiquitin, 20S proteasome subunit and GADD153/CHOP in the retina. Its retinal degenerative effect was also associated with reduced retinal neurofilament light chain gene expression, reflecting retinal ganglion cell death. MG-262-induced neurofilament light chain downregulation was largely resistant to pharmacological modulation including endoplasmic reticulum stress, apoptosis or MAP kinase inhibitors. Thus, this study provides further evidence of roles for the ubiquitin-proteasome system in the maintenance of the retinal structural integrity. Chemical proteasome inhibition may be used as a novel animal model of inner retinal degeneration, including retinal ganglion cell loss, which warrants further analysis of the molecular mechanisms underlying its retinal degenerative effect.


Assuntos
Complexo de Endopeptidases do Proteassoma/genética , Inibidores de Proteassoma/farmacologia , Retina/patologia , Degeneração Retiniana/patologia , Animais , Apoptose/efeitos dos fármacos , Ácidos Borônicos/efeitos adversos , Ácidos Borônicos/farmacologia , Modelos Animais de Doenças , Retículo Endoplasmático/efeitos dos fármacos , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Humanos , Complexo de Endopeptidases do Proteassoma/efeitos dos fármacos , Ratos , Retina/efeitos dos fármacos , Degeneração Retiniana/induzido quimicamente , Degeneração Retiniana/metabolismo , Células Ganglionares da Retina/efeitos dos fármacos , Células Ganglionares da Retina/patologia , Tapsigargina/efeitos adversos , Tapsigargina/farmacologia , Tunicamicina/efeitos adversos , Tunicamicina/farmacologia
15.
PLoS Pathog ; 15(6): e1007722, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31170268

RESUMO

Therapeutics with novel modes of action and a low risk of generating resistance are urgently needed to combat drug-resistant Plasmodium falciparum malaria. Here, we report that the peptide vinyl sulfones WLL-vs (WLL) and WLW-vs (WLW), highly selective covalent inhibitors of the P. falciparum proteasome, potently eliminate genetically diverse parasites, including K13-mutant, artemisinin-resistant lines, and are particularly active against ring-stage parasites. Selection studies reveal that parasites do not readily acquire resistance to WLL or WLW and that mutations in the ß2, ß5 or ß6 subunits of the 20S proteasome core particle or in components of the 19S proteasome regulatory particle yield only hundred-fold decreases in susceptibility. We observed no cross-resistance between WLL and WLW. Moreover, most mutations that conferred a modest loss of parasite susceptibility to one inhibitor significantly increased sensitivity to the other. These inhibitors potently synergized multiple chemically diverse classes of antimalarial agents, implicating a shared disruption of proteostasis in their modes of action. These results underscore the potential of targeting the Plasmodium proteasome with covalent small molecule inhibitors as a means of combating multidrug-resistant malaria.


Assuntos
Antimaláricos/farmacologia , Resistência a Medicamentos/efeitos dos fármacos , Plasmodium falciparum/enzimologia , Complexo de Endopeptidases do Proteassoma/metabolismo , Inibidores de Proteassoma/farmacologia , Proteínas de Protozoários , Antimaláricos/química , Resistência a Medicamentos/genética , Sinergismo Farmacológico , Humanos , Plasmodium falciparum/genética , Inibidores de Proteassoma/química , Proteínas de Protozoários/antagonistas & inibidores , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo
16.
Methods Mol Biol ; 1988: 1-14, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31147928

RESUMO

Proteasomes are the main cytosolic proteases responsible for generating peptides for antigen processing and presentation in the MHC (major histocompatibility complex) class-I pathway. Purified 20S and 26S proteasomes have been widely used to study both specificity and efficiency of antigen processing. Here, we describe the purification of active human 20S and 26S proteasomes from human erythrocytes by DEAE-ion exchange chromatography, ammonium sulfate precipitation, glycerol density gradient centrifugation, and Superose-6 size exclusion chromatography and their characterization using fluorogenic substrates and specific inhibitors.


Assuntos
Bioensaio/métodos , Citosol/enzimologia , Complexo de Endopeptidases do Proteassoma/isolamento & purificação , Centrifugação com Gradiente de Concentração , Precipitação Química , Cromatografia em Gel , Cromatografia por Troca Iônica , Eritrócitos/enzimologia , Corantes Fluorescentes/metabolismo , Humanos , Inibidores de Proteassoma/farmacologia , Especificidade por Substrato/efeitos dos fármacos
17.
Jpn J Clin Oncol ; 49(8): 695-702, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31187860

RESUMO

The prognosis of multiple myeloma was quite poor in the last century, but it has significantly improved with the incorporation of novel agents, immunomodulatory drugs (IMiDs) and proteasome inhibitors. Thalidomide was first developed as a sedative in 1950s, but it was withdrawn from the market because of teratogenicity. In 1990s, however, thalidomide received attention due to the discovery of its anticancer potential derived from antiangiogenic and immunomodulatory activities, and its therapeutic effect on myeloma. In 2006, the U.S. Food and Drug Administration approved the use of thalidomide under strict control for the treatment of multiple myeloma. After that, two new IMiDs, lenalidomide and pomalidomide, were developed for the sake of more antitumor activity and less adverse events than thalidomide. The molecular mechanism of action of IMiDs remained unclear for a long time until 2010 when the protein cereblon (CRBN) was identified as a primary direct target. IMiDs binds to CRBN and alters the substrate specificity of the CRBN E3 ubiquitin ligase complex, resulting in breakdown of intrinsic downstream proteins such as IKZF1 (Ikaros) and IKZF3 (Aiolos). There are many clinical trials of multiple myeloma using IMiDs under various conditions, and most of them show the efficacy of IMiDs. Nowadays lenalidomide plays a central role in both newly diagnosed and relapsed/refractory settings, mainly in combination with other novel agents such as proteasome inhibitors and monoclonal antibodies. This review presents an overview of recent advances in immunomodulatory drugs in the treatment of multiple myeloma.


Assuntos
Fatores Imunológicos/uso terapêutico , Mieloma Múltiplo/tratamento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Humanos , Fatores Imunológicos/química , Inibidores de Proteassoma/uso terapêutico , Ensaios Clínicos Controlados Aleatórios como Assunto , Transplante de Células-Tronco
18.
Nat Chem ; 11(7): 644-652, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31182821

RESUMO

A promising approach in cancer therapy is to find ligands that directly bind ubiquitin (Ub) chains. However, finding molecules capable of tightly and specifically binding Ub chains is challenging given the range of Ub polymer lengths and linkages and their subtle structural differences. Here, we use total chemical synthesis of proteins to generate highly homogeneous Ub chains for screening against trillion-member macrocyclic peptide libraries (RaPID system). De novo cyclic peptides were found that can bind tightly and specifically to K48-linked Ub chains, confirmed by NMR studies. These cyclic peptides protected K48-linked Ub chains from deubiquitinating enzymes and prevented proteasomal degradation of Ub-tagged proteins. The cyclic peptides could enter cells, inhibit growth and induce programmed cell death, opening new opportunities for therapeutic intervention. This highly synthetic approach, with both protein target generation and cyclic peptide discovery performed in vitro, will make other elaborate post-translationally modified targets accessible for drug discovery.


Assuntos
Lisina/química , Peptídeos Cíclicos/metabolismo , Bibliotecas de Moléculas Pequenas/metabolismo , Ubiquitinas/metabolismo , Antineoplásicos/metabolismo , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cisteína Endopeptidases/metabolismo , Inibidores de Cisteína Proteinase/metabolismo , Inibidores de Cisteína Proteinase/farmacologia , Células HeLa , Humanos , Estrutura Molecular , Peptídeos Cíclicos/farmacologia , Complexo de Endopeptidases do Proteassoma/metabolismo , Inibidores de Proteassoma/metabolismo , Inibidores de Proteassoma/farmacologia , Ligação Proteica , Bibliotecas de Moléculas Pequenas/farmacologia , Ubiquitinas/síntese química , Ubiquitinas/química
19.
Biol Pharm Bull ; 42(5): 764-769, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31061318

RESUMO

Werner helicase-interacting protein 1 (WRNIP1) was originally identified as a protein that interacts with WRN, the product of the gene responsible for Werner syndrome. Our previous studies suggested that WRNIP1 is implicated in translesion synthesis (TLS), a process in which specialized TLS polymerases replace replicative DNA polymerase and take over DNA synthesis on damaged templates. We proposed that a novel error-free pathway involving DNA polymerase δ and primase-polymerase (PrimPol) functions to synthesize DNA on UV-damaged DNA templates in the absence of WRNIP1 and the TLS polymerase Polη. Hence, in the current study, we analyzed the relationship between WRNIP1 and PrimPol. We found that WRNIP1 and PrimPol form a complex in cells. PrimPol protein expression was reduced in cells overexpressing WRNIP1, but was increased in WRNIP1-depleted cells. The WRNIP1-mediated reduction in the amount of PrimPol was suppressed by treatment of the cells with proteasome inhibitors, suggesting that WRNIP1 is involved in the degradation of PrimPol via the proteasome.


Assuntos
ATPases Associadas a Diversas Atividades Celulares/metabolismo , DNA Primase/metabolismo , Proteínas de Ligação a DNA/metabolismo , DNA Polimerase Dirigida por DNA/metabolismo , Enzimas Multifuncionais/metabolismo , ATPases Associadas a Diversas Atividades Celulares/genética , DNA Primase/genética , DNA Complementar/genética , Proteínas de Ligação a DNA/genética , DNA Polimerase Dirigida por DNA/genética , Células HEK293 , Humanos , Enzimas Multifuncionais/genética , Plasmídeos , Inibidores de Proteassoma/farmacologia , RNA Mensageiro/metabolismo , Transfecção
20.
Yakugaku Zasshi ; 139(5): 651-661, 2019.
Artigo em Japonês | MEDLINE | ID: mdl-31061332

RESUMO

This review describes two novel synthetic routes from (S)-pyroglutaminol to (+)-lactacystin, a potent inhibitor of the 20S proteasome and from d-gluconolactone derivative to zaragozic acid C, a potent squalene synthase inhibitor. In lactacystin synthesis, the photoinduced intermolecular C(sp3)-H alkynylation and intramolecular C(sp3)-H acylation chemoselectively and stereoselectively constructed the tetrasubstituted and trisubstituted carbon centers, respectively. In the synthesis of zaragozic acid C, the stereoselective installation of the two contiguous tetrasubstituted carbons was achieved by the photochemical intramolecular C(sp3)-H acylation of a densely oxygenated intermediate.


Assuntos
Acetilcisteína/análogos & derivados , Produtos Biológicos/síntese química , Compostos Bicíclicos Heterocíclicos com Pontes/síntese química , Inibidores Enzimáticos/síntese química , Oxigênio/química , Processos Fotoquímicos , Inibidores de Proteassoma/síntese química , Acetilcisteína/síntese química , Acilação , Alquilação , Carbono/química , Farnesil-Difosfato Farnesiltransferase/antagonistas & inibidores , Radicais Livres/química , Gluconatos/química , Lactonas/química , Oxirredução , Complexo de Endopeptidases do Proteassoma , Pirróis/química , Estereoisomerismo
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