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)

More effective therapies are needed for non-small-cell lung cancer (NSCLC) and small-cell lung cancer (SCLC). Proteasome inhibitors are one class of molecularly targeted antineoplastic agents being investigated for these diseases. These agents block the activity of the 26S proteasome, which is responsible for the degradation of the vast majority of intracellular proteins and thus affect multiple signaling pathways within cells. Bortezomib is the first proteasome inhibitor to be evaluated in human studies and is approved for use in multiple myeloma. Bortezomib is now being investigated as a potential treatment for NSCLC and SCLC. Preclinical studies have shown that single-agent bortezomib causes growth inhibition and apoptosis in numerous NSCLC cell lines in vitro and has antitumor activity in vivo. Bortezomib affects the levels of several proteins known to be of significance in lung cancers. Studies of bortezomib in combination with other antitumor agents in vitro and in vivo demonstrate that these combination regimens can offer additive/synergistic effects compared with the single agents. Bortezomib has been investigated in combination with taxanes, gemcitabine, carboplatin, histone deactylase inhibitors, and other molecularly targeted agents in various NSCLC cell lines. The sequence of administration of the agents in preclinical combination regimens in vitro and in vivo has been shown to be of significance; further elucidation of the mechanism of efficacy of bortezomib in lung cancer is required. Numerous clinical studies have been carried out or are ongoing. Bortezomib has the potential to play a significant role in the future management of NSCLC and SCLC.
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PMID:Preclinical data with bortezomib in lung cancer. 1625 Sep 27

The 26S proteasome is a multicatalytic threonine protease complex that is responsible for intracellular protein turnover in eukaryotic cells. This complex degrades and processes proteins required for regulation of various cellular functions. Bortezomib is a novel proteasome inhibitor approved for therapy of multiple myeloma. Inhibition of ubiquitin-proteasome-mediated protein degradation by bortezomib leads to accumulation of its diverse substrates, including cyclins, transcriptional factors, tumor suppressor proteins, and protooncogenes. The sequelae of such profound perturbation of cellular function include cell cycle arrest and activation of apoptotic programs. As the development of this agent continues, there is interest in evaluating its interaction with other anticancer agents. This review provides an overview of selected interactions between bortezomib and other anticancer agents preclinically and in early clinical trials.
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PMID:Sequencing bortezomib with chemotherapy and targeted agents. 1625 Sep 28

The combination of chemotherapy and radiation has been validated for the treatment of locally advanced non-small-cell lung cancer (NSCLC). However, the results are still unsatisfactory, and there is a need to improve current treatment. One approach is to use new agents that have the potential to enhance the efficacy of chemotherapy, radiation therapy (RT), or both. One potential target is the ubiquitin-proteasome pathway. This pathway plays an essential role in the degradation of most short- and long-lived intracellular proteins in eukaryotic cells and therefore regulating the cell cycle, neoplastic growth, and metastasis. Bortezomib is a selective 26S proteasome inhibitor that has been approved for the treatment of multiple myeloma. Bortezomib has demonstrated in vitro chemotherapy- and RT-sensitizing properties as well as single-agent activity in lung cancer. This article will review the rationale for the use of bortezomib as part of the chemotherapy/RT strategy for the treatment of NSCLC.
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PMID:The potential role of bortezomib in combination with chemotherapy and radiation in non-small-cell lung cancer. 1625 Sep 30

Cellular homeostasis requires routine degradation of key regulatory proteins, including tumor suppressor gene products, transcription factors, cell-cycle proteins and their inhibitors, as well as damaged and misfolded proteins. A critical part of this process is mediated by the 26S proteasome, a multi-subunit enzyme found in the nucleus and cytoplasm of all eukaryotic cells. Because of its essential role in many cellular processes controlling growth and survival, the proteasome has been identified as a potential target for cancer therapy. Drugs known to inhibit proteasome activity have been shown to induce cell-cycle arrest and programmed cell death (apoptosis). The impact of this finding is heightened by research showing that cancer cells are more sensitive to the proapoptotic effects of proteasome inhibition than normal cells. Preclinical evidence using bortezomib, the only proteasome inhibitor to enter clinical trials, suggests that proteasome inhibition may be effective in the treatment of hematologic and solid malignancies by promoting apoptosis, retarding angiogenesis, and inhibiting tumor cell adhesion and production of growth factors by acting on molecules such as nuclear factor-kappaB. Further preclinical evidence suggests that the antitumor effects of cytotoxic chemotherapy or radiotherapy may be enhanced by the addition of a proteasome inhibitor. Bortezomib was recently approved for the treatment of multiple myeloma. It is currently being investigated, both as a single agent and in combination, in phase I and II trials in a variety of tumor types.
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PMID:Bortezomib: a novel therapy approved for multiple myeloma. 1625 56

Myeloma vaccines, based on dendritic cells pulsed with idiotype or tumor lysate, have been met with limited success, probably in part due to insufficient cross-priming of myeloma antigens. A powerful method to introduce myeloma-associated antigens into the cytosol of dendritic cells is protein transduction, a process by which proteins fused with a protein transduction domain (PTD) freely traverse membrane barriers. NY-ESO-1, an immunogenic antigen by itself highly expressed in 60% of high-risk myeloma patients, was purified to near homogeneity both alone and as a recombinant fusion protein with a PTD, derived from HIV-Tat. Efficient entry of PTD-NY-ESO-1 into dendritic cells, confirmed by microscopy, Western blotting, and intracellular flow cytometry, was achieved without affecting dendritic cell phenotype. Experiments with amiloride, which inhibits endocytosis, and N-acetyl-l-leucinyl-l-norleucinal, a proteasome inhibitor, confirmed that PTD-NY-ESO-1 entered dendritic cells by protein transduction and was degraded by the proteasome. Tetramer analysis indicated superior generation of HLA-A2.1, CD8+ T lymphocytes specific for NY-ESO-1(157-165) with PTD-NY-ESO-1 compared with NY-ESO-1 control protein (44% versus 2%, respectively). NY-ESO-1-specific T lymphocytes generated with PTD-NY-ESO-1 secreted IFN-gamma indicative of a Tc1-type cytokine response. Thus, PTD-NY-ESO-1 accesses the cytoplasm by protein transduction, is processed by the proteasome, and NY-ESO-1 peptides presented by HLA class I elicit NY-ESO-1-specific T lymphocytes.
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PMID:Protein transduction of dendritic cells for NY-ESO-1-based immunotherapy of myeloma. 1626 30

The success of bortezomib, a competitive proteasome inhibitor and a drug approved to treat multiple myeloma, spurred interest in compounds targeting catalytic sites of the enzyme. The aim of this chapter, however, is to focus attention on the small molecule, natural or synthetic compounds binding far away from the catalytic centers, yet modifying the performance of the proteasome. Defining allostery broadly as any kind of ligand-induced, long-distance transfer of conformational signals within a molecule, most such compounds are allosteric effectors capable of regulating the proteasome in vitro and in vivo in a manner more diverse and precise than competitive inhibitors. Proline- and arginine-rich peptides (PR peptides) are examples of such compounds and are currently being considered as potential drugs with anti-inflammatory and proangiogenic activities. This chapter describes a set of methods useful for characterizing the effects of such inhibitors on the proteasome.
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PMID:Characterization of noncompetitive regulators of proteasome activity. 1627 48

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

Although there is effective chemotherapy for many patients with leukemia, 20% of children and up to 65% of adults relapse. Novel therapies are needed to treat these patients. Leukemia cells are very sensitive to the proteasome inhibitor bortezomib (VELCADE(R), PS-341), which enhances the in vitro cytotoxic effects of dexamethasone and doxorubicin in multiple myeloma. To determine if bortezomib enhances the cytotoxicity of agents used in leukemia, we employed an in vitro tetrazolium-based colorimetric assay (MTT) to evaluate the cytotoxic effects of bortezomib alone and in combination with dexamethasone, vincristine, doxorubicin, cytarabine, asparaginase, geldanamycin, trichostatin A, and the bcl-2 inhibitor HA14.1. We demonstrated that primary leukemia lymphoblasts and leukemia cell lines are sensitive to bortezomib, with an average IC(50) of 12 nM. Qualitative and quantitative bortezomib-drug interactions were evaluated using the universal response surface approach (URSA). Bortezomib was synergistic with dexamethasone in dexamethasone-sensitive leukemia cells, and additive with vincristine, asparaginase, cytarabine, and doxorubicin. The anti-leukemic activity of bortezomib was also additive with geldanamycin and HA14.1, and additive or synergistic with trichostatin A. These results were compared to analysis using the median-dose effect method, which generated complex drug interactions due to differences in dose-response curve sigmoidicities. These data suggest bortezomib could potentiate the cytotoxic effects of combination chemotherapy in patients with leukemia.
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PMID:Bortezomib interactions with chemotherapy agents in acute leukemia in vitro. 1629 37

Proteasome inhibition is a novel approach to treating malignancy, and bortezomib is the first proteasome inhibitor in this class to be approved for clinical use. In preclinical studies, bortezomib caused cell cycle arrest and apoptosis in myeloma and lymphoma cell lines as well as in other neoplastic cell types. Phase I clinical trials established an optimal dosing strategy and demonstrated a manageable toxicity profile. Cyclical thrombocytopenia and peripheral neuropathy, which generally abate after cessation of treatment, are the most clinically significant toxicities. Two phase II trials, SUMMIT and CREST, demonstrated impressive activity with bortezomib 1.3 mg/m2 monotherapy in relapsed and refractory myeloma, with an impressive 35% response rate (complete+partial+minimal responses) in SUMMIT and a 50% response rate in CREST, using the rigorous European Group for Blood and Marrow Transplantation criteria. A recently completed phase III trial showed the significant clinical benefits of bortezomib over high-dose dexamethasone in patients with relapsed myeloma. Results of ongoing trials with bortezomib in the first-line treatment of myeloma have been extremely encouraging and have demonstrated the benefit of using bortezomib as part of an induction regimen prior to stem cell transplantation. Importantly, two clinical trials with bortezomib as monotherapy in refractory non-Hodgkin's lymphoma have shown impressive response rates, particularly in aggressive mantle cell lymphoma.
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PMID:Bortezomib, a novel proteasome inhibitor, in the treatment of hematologic malignancies. 1629 74

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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PMID:The ubiquitin proteasome pathway from bench to bedside. 1630 84


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