Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026764 (multiple myeloma)
 36,148 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bortezomib therapy has proven successful for the treatment of relapsed and/or refractory multiple myeloma (MM); however, prolonged treatment is associated with toxicity and development of drug resistance. Here, we show that the novel proteasome inhibitor NPI-0052 induces apoptosis in MM cells resistant to conventional and Bortezomib therapies. NPI-0052 is distinct from Bortezomib in its chemical structure, effects on proteasome activities, mechanisms of action, and toxicity profile against normal cells. Moreover, NPI-0052 is orally bioactive. In animal tumor model studies, NPI-0052 is well tolerated and prolongs survival, with significantly reduced tumor recurrence. Combining NPI-0052 and Bortezomib induces synergistic anti-MM activity. Our study therefore provides the rationale for clinical protocols evaluating NPI-0052, alone and together with Bortezomib, to improve patient outcome in MM.
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PMID:A novel orally active proteasome inhibitor induces apoptosis in multiple myeloma cells with mechanisms distinct from Bortezomib. 1628 48

Second mitochondria-derived activator of caspases (Smac) promotes apoptosis via activation of caspases. Here we show that a low-molecular-weight Smac mimetic LBW242 induces apoptosis in multiple myeloma (MM) cells resistant to conventional and bortezomib therapies. Examination of purified patient MM cells demonstrated similar results, without significant cytotoxicity against normal lymphocytes and bone marrow stromal cells (BMSCs). Importantly, LBW242 abrogates paracrine MM cell growth triggered by their adherence to BMSCs and overcomes MM cell growth and drug-resistance conferred by interleukin-6 or insulinlike growth factor-1. Overexpression of Bcl-2 similarly does not affect LBW242-induced cytotoxicity. Mechanistic studies show that LBW242-induced apoptosis in MM cells is associated with activation of caspase-8, caspase-9, and caspase-3, followed by PARP cleavage. In human MM xenograft mouse models, LBW242 is well tolerated, inhibits tumor growth, and prolongs survival. Importantly, combining LBW242 with novel agents, including tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) or the proteasome inhibitors bortezomib and NPI-0052, as well as with the conventional anti-MM agent melphalan, induces additive/synergistic anti-MM activity. Our study therefore provides the rationale for clinical protocols evaluating LBW242, alone and together with other anti-MM agents, to improve patient outcome in MM.
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PMID:Targeting mitochondrial factor Smac/DIABLO as therapy for multiple myeloma (MM). 1703 24

Proteasome inhibitor Bortezomib/Velcade has emerged as an effective anticancer therapy for the treatment of relapsed and/or refractory multiple myeloma (MM), but prolonged treatment can be associated with toxicity and development of drug resistance. In this review, we discuss the recent discovery of a novel proteasome inhibitor, NPI-0052, that is distinct from Bortezomib in its chemical structure, mechanisms of action, and effects on proteasomal activities; most importantly, it overcomes resistance to conventional and Bortezomib therapies. In vivo studies using human MM xenografts shows that NPI-0052 is well tolerated, prolongs survival, and reduces tumour recurrence. These preclinical studies provided the basis for Phase-I clinical trial of NPI-0052 in relapsed/refractory MM patients.
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PMID:A novel proteasome inhibitor NPI-0052 as an anticancer therapy. 1704 43

Salinosporamide A (NPI-0052; 3), a highly potent inhibitor of the 20S proteasome, is currently in phase I clinical trials for the treatment of cancer. During the course of purifying multigram quantities of 3 from Salinispora tropica fermentation extracts, several new salinosporamides were isolated and characterized, most of which represent modifications to the chloroethyl substituent at C-2. Specifically, 3 was isolated along with the known compound salinosporamide B (4), the previously undescribed methyl congener salinosporamide D (7), and C-2 epimers of 3 and 7 (salinosporamides F (9) and G (10), respectively). Salinosporamide I (13), in which the methyl group at the ring junction is replaced with an ethyl group, and the C-5 deshydroxyl analogue salinosporamide J (14), were also identified. Replacement of synthetic sea salt with sodium bromide in the fermentation media produced bromosalinosporamide (12), 4, and its C-2 epimer (11, salinosporamide H). In addition to these eight new salinosporamides, several thioester derivatives were generated semisynthetically. IC50 values for cytotoxicity against human multiple myeloma cell line RPMI 8226 and inhibition of the chymotrypsin-like (CT-L) activity of purified rabbit 20S proteasomes were determined for all compounds. The results indicate that thioesters may directly inhibit the proteasome, albeit with reduced potency compared to their beta-lactone counterparts.
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PMID:Salinosporamides D-J from the marine actinomycete Salinispora tropica, bromosalinosporamide, and thioester derivatives are potent inhibitors of the 20S proteasome. 1724 24

The proteasome has been successfully targeted for the treatment of multiple myeloma and mantle cell lymphoma; however, in other hematologic malignancies, bortezomib has been less effective as a single agent. Here, we describe effects of NPI-0052, a novel proteasome inhibitor, in leukemia model systems. In cell lines, NPI-0052 inhibits all 3 proteolytic activities associated with the proteasome: chymotrypsin-, trypsin-, and caspase-like. NPI-0052 also induces DNA fragmentation in leukemia lines and in mononuclear cells from a Ph + acute lymphoblastic leukemia (ALL) patient. Caspase-3 activation by NPI-0052 was seen in wild-type Jurkat cells, but was significantly lessened in Fas-associated death domain (FADD)-deficient or caspase-8-deficient counterparts. NPI-0052-induced apoptosis was further probed using caspase-8 inhibitors, which were more protective than caspase-9 inhibitors. N-acetyl cysteine (NAC) also conferred protection against NPI-0052-induced apoptosis, indicating a role for oxidative stress by NPI-0052. In support of the drug's in vitro activities, biweekly treatment with NPI-0052 lessened total white blood cell (WBC) burden over 35 days in leukemic mice. Interestingly, combining NPI-0052 with either MS-275 or valproic acid (VPA) induced greater levels of cell death than the combination of bortezomib with these histone deacetylase inhibitors (HDACi). These effects of NPI-0052, alone and in combination with HDACi, warrant further testing to determine the compound's clinical efficacy in leukemia.
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PMID:NPI-0052, a novel proteasome inhibitor, induces caspase-8 and ROS-dependent apoptosis alone and in combination with HDAC inhibitors in leukemia cells. 1735 34

Multiple myeloma (MM) remains incurable, but recent advances in genomics and proteomics have allowed for advances in our understanding of disease pathogenesis, identified novel therapeutic targets, allowed for molecular classification, and provided the scientific rationale for combining targeted therapies to increase tumor cell cytotoxicity and abrogate drug resistance. Besides these advances, recognition of the role of the bone marrow (BM) milieu in conferring growth, survival, and drug resistance in MM cells, both in laboratory and animal models, has allowed for the establishment of a new treatment paradigm targeting the tumor cell and its microenvironment to overcome drug resistance and improve patient outcomes in MM. In particular, thalidomide, bortezomib, and lenalidamide all overcome conventional drug resistance, not only by directly inducing tumor cell cytotoxicity, but by inhibiting adhesion of MM cells to BM. This abrogates constitutive and MM-binding-induced transcription and secretion of cytokines, inhibits angiogenesis, and augments host anti-MM immunity. These three drugs have rapidly translated from bench to bedside and in treatment protocols of MM, first in patients with relapsed refractory disease, and then alone and in combination in newly diagnosed patients. Promising novel targeted agents include the novel proteasome inhibitor NPI-0052 and the heat shock protein inhibitor KOS-953. Importantly, gene-array, proteomic, and cell-signaling studies have not only helped to identify in vivo mechanisms of action and drug resistance to novel agents, but also aided in the design of promising combination-therapy protocols.
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PMID:Targeted therapy of multiple myeloma based upon tumor-microenvironmental interactions. 1737 1

Our recent study demonstrated that a novel proteasome inhibitor NPI-0052 triggers apoptosis in multiple myeloma (MM) cells, and importantly, that is distinct from bortezomib (Velcade) in its chemical structure, effects on proteasome activities, and mechanisms of action. Here, we demonstrate that combining NPI-0052 and bortezomb induces synergistic anti-MM activity both in vitro using MM cell lines or patient CD138(+) MM cells and in vivo in a human plasmacytoma xenograft mouse model. NPI-0052 plus bortezomib-induced synergistic apoptosis is associated with: (1) activation of caspase-8, caspase-9, caspase-3, and PARP; (2) induction of endoplasmic reticulum (ER) stress response and JNK; (3) inhibition of migration of MM cells and angiogenesis; (4) suppression of chymotrypsin-like (CT-L), caspase-like (C-L), and trypsin-like (T-L) proteolytic activities; and (5) blockade of NF-kappaB signaling. Studies in a xenograft model show that low dose combination of NPI-0052 and bortezomib is well tolerated and triggers synergistic inhibition of tumor growth and CT-L, C-L, and T-L proteasome activities in tumor cells. Immununostaining of MM tumors from NPI-0052 plus bortezomib-treated mice showed growth inhibition, apoptosis, and a decrease in associated angiogenesis. Taken together, our study provides the preclinical rationale for clinical protocols evaluating bortezomib together with NPI-0052 to improve patient outcome in MM.
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PMID:Combination of proteasome inhibitors bortezomib and NPI-0052 trigger in vivo synergistic cytotoxicity in multiple myeloma. 1800 97

Within the last decade, several novel classes of anti-myeloma therapeutics have become available. The clinical successes achieved by thalidomide, lenalidomide, and the proteasome inhibitor bortezomib, and in particular the ability of these agents to lead to major clinical responses in patients resistant to conventional or high-dose chemotherapy, have highlighted the importance of expanding further the spectrum of classes of agents utilized for the treatment of myeloma. Herein, we review the current status for the development of novel anti-myeloma agents, with emphasis on classes of therapeutics which have already translated into clinical trials or those in advanced stages of preclinical development. These include second-generation proteasome inhibitors (NPI-0052 and PR-171), heat shock protein 90 (hsp90) inhibitors, 2-methoxyestradiol, histone deacetylase (HDAC) inhibitors (e.g. SAHA and LBH589), fibroblast growth factor receptor 3 (FGF-R3) inhibitors, insulin-like growth factor 1 receptor (IGF-1R) inhibitors, mTOR inhibitors, monoclonal antibodies, and agents specifically targeting the tumor microenvironment, such as defibrotide.
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PMID:From the bench to the bedside: emerging new treatments in multiple myeloma. 1807 Jul 20

Proteasome inhibitors (PIs), such as bortezomib, carfilzomib or NPI-0052, have excellent clinical activity in patients with multiple myeloma and mantle cell lymphoma, and they are currently being evaluated in combination with other agents in patients with solid tumors. Although they exert broad effects on cancer cells, their ability to (1) stabilize pro-apoptotic members of the BCL-2 family, (2) inhibit the two major pathways leading to NFkappaB activation, and (3) cause the build-up of misfolded proteins appear to be particularly important. In addition, PIs may disrupt tumor-stromal interactions that drive NFkappaB activation and angiogenesis and in such a way sensitize cancer cells to other agents. Still, drug resistance ultimately emerges in all tumors that initially respond to PIs. This review provides an overview of the current thinking about how PIs may kill cancer cells exemplified for pancreatic cancer and the possible mechanisms involved in resistance to PIs.
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PMID:Mechanisms of proteasome inhibitor action and resistance in cancer. 1881 17

New chemotherapeutic agents are still required to further optimise treatment of leukemia patients. Proteasome inhibition by bortezomib, PR-171 (carfilzomib) and NPI-0052 (salinosporamide A) has been successfully used for the treatment of multiple myeloma and mantle cell lymphoma and is considered also as novel treatment strategy in leukemia. Combination of proteasome inhibitors bortezomib and NPI-0052 induces synergistic anti-multiple myeloma activity both in vitro using multiple myeloma cells and in vivo in a human plasmacytoma xenograft mouse model. Cell death resulting from proteasome inhibition requires caspase activation and increased levels of reactive oxygen species. While bortezomib induces several caspases, NPI-0052 activates predominantly caspase-8-dependent pathway. We studied the effect of bortezomib (10 nM) on DNA synthesis and apoptosis in human acute myeloid cell lines KASUMI-1, ML-1, ML-2 and CTV-1 cells. Bortezomib was potent inhibitor of DNA synthesis in all four types of leukemia cells and induced apoptosis in KASUMI-1, ML-2 and CTV-1 cells but not in ML-1 cells. Other research groups showed that histone deacetylase inhibitors (valproic acid or benzamide derivative MS-275) in combination with NPI-0052 or PR-171 induced greater levels of acute leukemia cell death than in combination with bortezomib. Proteasome inhibition as monotherapy and its combination with many conventional therapies as novel treatment strategies in leukemia are promising. Malignant cells are more sensitive to this treatment than normal hematopoietic cells.
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PMID:Antiproliferative and proapoptotic effects of proteasome inhibitors and their combination with histone deacetylase inhibitors on leukemia cells. 1927 78


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