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 (1) is a potent first-in-class dipeptidyl boronic acid proteasome inhibitor employed in the treatment of patients with relapsed multiple myeloma where the disease is refractory to conventional lines of therapy. The potency of 1 is owed primarily to the presence of the boronic acid moiety, one which is suited to establish a tetrahedral intermediate with the active site N-terminal threonine residue of the proteasome. Hence, deboronation of 1 represents a deactivation pathway for this chemotherapeutic agent. Deboronation of 1 affords a near equal mixture of diastereomeric carbinolamide metabolites (M1/M2) and represents the principal metabolic pathway observed in humans. In vitro results from human liver microsomes and human cDNA-expressed cytochrome P450 enzymes (P450) indicate a role for P450 in the deboronation of 1. Use of 18O-labeled oxygen under controlled atmospheres confirmed an oxidative mechanism in the P450-mediated deboronation of 1, as 18O was found incorporated in both M1 and M2. Chemically generated reactive oxygen species (ROS), such as those generated as byproducts during P450 catalysis, were also found to deboronate 1 resulting in the formation of M1 and M2. Known to undergo efficient redox cycling, P450 2E1 was found to catalyze the deboronation of 1 predominantly to the carbinolamide metabolites M1 and M2, as well as to a pair of peroxycarbinolamides, 2 and 3. The presence of superoxide dismutase (SOD) and catalase prevented the deboronation of 1, thus, supporting the involvement of ROS in the P450 2E1-catalyzed deboronation reaction. The presence of SOD and catalase also protected 1 against P450 3A4-catalyzed deboronation, albeit to a lesser extent. The remaining deboronation activity observed in the P450 3A4 reaction may suggest the involvement of the more conventional activated enzyme-oxidants previously described for P450. Our present findings indicate that the oxidase activity of P450 (i.e., formation of ROS) represents a mechanism of deboronation.
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PMID:Oxidative deboronation of the peptide boronic acid proteasome inhibitor bortezomib: contributions from reactive oxygen species in this novel cytochrome P450 reaction. 1660 65

A macrokinetic model for a myeloma cell line is proposed. The model describes the dynamic balances of lactate, alanine, ATP and NADH during the metabolsim of glucose, glutamine and other amino acids. The metabolic pathways mainly include glycolysis, glutaminolysis, the trcicarboxylic acid cycle, the formation and utilization of amino acids, the respiratory chain, cell growth and cell death. The metabolic shift of glucose is especially considered because of a change in the rate of glycolysis. Thus the model functions in three modes to describe the behaviour of the myeloma cell line. On the basis of this model the macrokinetic bioreaction rates such as the specific substrate consumption rate, the specific growth rate, the specific acetyl-CoA formation rate, as well as the specific oxygen uptake rate, are estimated. The specific substrate consumption rate and the specific growth rate are then coupled into a bioreactor model such that the key variables, i.e., the cell density, the substrate and metabolite concentrations, are obtained. Experiments with batch and fed-batch cultures of a myeloma cell line (X63-Ag8.653) were used to validate the model. The prediction of the model was simulated by the rolling prediction approach.
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PMID:A macrokinetic model for myeloma cell culture based on stoichiometric balance. 1680 Aug 13

To investigate the effect of velcade on multiple myeloma cell line U266 apoptosis and its mechanism, cell viability was estimated by trypan blue dye exclusion. Annexin-V, mitochondrial transmembrane potential (delta psi m) and reactive oxygen species (ROS) labeled by DCFHDA were examined by flow cytometry, the expression of bcl-2 mRNA was detected by semi-quantitative RT-PCR. The results showed that the velcade inhibited the growth of U266 cells and reduced cell viability accompanied by appearance of morphologic characteristics of apoptosis. Velcade at 50 nmol/L increased Annexin V positivity and fluorescence intensity of DCF because of ROS generation while it decreased the delta psi m of U266 cells. Expression of anti-apoptotic gene bcl-2 mRNA also decreased. It is concluded that velcade inhibited the growth and reduce cell viability of U266 cells. Velcade can induce U266 cells apoptosis by intrinsic cell apoptotic pathway.
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PMID:[Multiple myeloma cell line U266 apoptosis induced by velcade]. 1692 2

Phosphatidylinositol-3-kinase (PI3K), and its downstream effector Akt, or protein kinase Balpha (PKBalpha), play a major regulatory role in control of apoptosis, proliferation, and angiogenesis. PI3K and Akt are amplified or overexpressed in a number of malignancies, including sarcomas, ovarian cancer, multiple myeloma, and melanoma. This pathway regulates production of the potent angiogenic factor vascular endothelial growth factor (VEGF), and protects tumor cells against both chemotherapy and reactive oxygen-induced apoptosis through phosphorylation of substrates such as apoptotic peptidase-activating factor-1 (APAF-1), forkhead proteins, and caspase 9. Given its diverse actions, compounds that suppress the PI3K/Akt pathway have potential pharmacologic utility as angiogenesis inhibitors and antineoplastic agents. Using the SVR angiogenesis assay, a screen of natural products, we isolated the alkaloid solenopsin, and found that it is a potent angiogenesis inhibitor. We also found that solenopsin inhibits the PI3K signaling pathway in cells upstream of PI3K, which may underlie its affects on angiogenesis. Consistent with inhibition of the activation of PI3K, solenopsin prevented the phosphorylation of Akt and the phosphorylation of its substrate forkhead box 01a (FOXO1a), a member of the forkhead family of transcription factors. Interestingly, solenopsin also inhibited Akt-1 activity in an ATP-competitive manner in vitro without affecting 27 of 28 other protein kinases tested.
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PMID:Solenopsin, the alkaloidal component of the fire ant (Solenopsis invicta), is a naturally occurring inhibitor of phosphatidylinositol-3-kinase signaling and angiogenesis. 1699 May 98

The effect and mode of action of the protein kinase C (PKC) inhibitor PKC412 on human multiple myeloma (MM) cell lines (HMCLs) and primary MM cells was explored. We found that PKC412 induced apoptosis of HMCLs and primary MM cells with variable efficacy; however, some activity was seen against all HMCLs and primary MM cells with at least 0.5 microM PKC412. PARP cleavage and decreased PKC activity was observed in all HMCLs tested. Furthermore, PKC412 inhibited C-FOS transcription and nuclear protein expression, induced reactive oxygen species (ROS) production, and induced both sustained C-JUN expression and phosphorylation. The latter was inhibited by cotreatment with the JNK inhibitor SP600125, which similarly abrogated PKC412-induced apoptosis, suggesting that PKC412-induced apoptosis is a JNK-dependent event. PKC412 treatment secondarily induced prosurvival stress responses as evidenced by activation of NFkappaB and increased expression of the heat shock proteins HSP70 and HSP90. Consistent with the former, sequential inhibition of NFkappaB activation with bortezomib or SN50 synergistically enhanced cell killing. Our results demonstrate that PKC412 induces JNK-dependent apoptosis of HMCLs and primary MM cells and that this effect is enhanced by NFkappaB inhibition. The further evaluation of PKC412 in the treatment of MM is justified.
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PMID:PKC412 demonstrates JNK-dependent activity against human multiple myeloma cells. 1703 22

A 60-year-old man with multiple myeloma (MM) (IgG-kappa, stage IIIA) had been treated with minodronate at 6 mg orally as a phase 1 clinical trial for myeloma bone disease for 13 months (total dose, 4032 mg). Then he received incadronate at 10mg intravenously every 1 to 4 weeks (total dose, 350 mg). In July 2005, he complained of mild right mandibular pain, and bone scintigram showed a hot spot at the right side of the mandible. Panoramic radiograph showed osteonecrosis of the jaw (ONJ) and axial and 3-dimensional computed tomography confirmed ONJ. Oral examination showed massive gingival swelling of the right side of the mandible without exposed necrotic bone. He was given clarithromycin in addition to levofloxacin, followed by hyperbaric oxygen (HBO) therapy, which resulted in the complete disappearance of the pain. This is a first reported case of ONJ induced by incadronate. The present case suggests that early detection of ONJ by regular dental check-ups is important in the management of patients with MM who have received bisphosphonate therapy, and HBO in combination with antibiotic therapy is effective in the early stage of ONJ.
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PMID:Hyperbaric oxygen in addition to antibiotic therapy is effective for bisphosphonate-induced osteonecrosis of the jaw in a patient with multiple myeloma. 1711 61

Osteonecrosis of the jaws is being increasingly reported in patients with bone metastasis from a variety of solid tumors and disseminated multiple myeloma receiving intravenous bisphosphonates. Agreement exists that these drugs can initiate vascular endothelial cell damage and accelerate disturbances in the microcirculation of the jaws, possibly resulting in thrombosis of nutrient-end arteries. The role of bisphosphonates in cancer patients with previously treated jaws has yet to be elucidated. The signs and symptoms that may occur before the appearance of evident osteonecrosis include changes in the health of periodontal tissues, nonhealing mucosal ulcers, loose teeth and unexplained soft tissue infection. A series of 30 periodontally involved patients showing osteonecrosis of the jaws that appeared following the intravenous use of bisphosphonates is reported. Clinical management of the avascular necrosis of the jaws in patients treated with bisphosphonates presents several problems. An analysis of the international medical literature shows that surgical treatment of the necrotic jaws in patients treated with bisphosphonates has proven to be ineffective in stopping the pathological process. The use of hyperbaric oxygen and antibiotics are not effective, either. The authors have developed a new protocol for the management of these lesions. Compared with other therapeutic choices, this protocol has introduced the use of ozone therapy as therapeutic support.
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PMID:New therapeutic protocol in the treatment of avascular necrosis of the jaws. 1711 9

Osteonecrosis of the jaw is an unremitting adverse outcome associated with bisphosphonate therapy in patients with multiple myeloma or bone metastases from solid tumors. Twelve patients who presented with exposed bone associated with bisphosphonates were reviewed to determine the type, dosage and duration of their bisphosphonate therapy, presenting findings, comorbidities and the event that incited the bone exposure. The discontinuation of bisphosphonate therapy has not helped reverse the presence of osteonecrosis, and the surgical manipulation of the involved site appears to worsen the underlying bone pathology. Hyperbaric oxygen, which has proven efficacious in other forms of osteonecrosis by establishing an oxygen gradient, is of no definitive benefit to patients with bisphosphonate-induced exposed bone. Antibiotic therapy is useful in controlling pain and swelling but ineffective in preventing the progression of the exposed bone. To date, prevention is the only currently possible therapeutic approach to the management of this complication.
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PMID:Bisphosphonate-associated osteonecrosis of the jaw in patients with multiple myeloma and breast cancer. 1716 81

Reactive oxygen species are known to be involved in several cellular processes, including cell signaling. SOD2 is a key enzyme in the conversion of reactive oxygen species and has been implicated in a host of disease states, including cancer. Using an integrated, whole-cell approach encompassing epigenetics, genomics, and proteomics, we have defined the role of SOD2 in multiple myeloma. We show that the SOD2 promoter is methylated in several cell lines and there is a correlative decrease in expression. Furthermore, myeloma patient samples have decreased SOD2 expression compared with healthy donors. Overexpression of SOD2 results in decreased proliferation and altered sensitivity to 2-methoxyestradiol-induced DNA damage and apoptosis. Genomic profiling revealed regulation of 65 genes, including genes involved in tumorigenesis, and proteomic analysis identified activation of the JAK/STAT pathway. Analysis of nearly 400 activated transcription factors identified 31 transcription factors with altered DNA binding activity, including XBP1, NFAT, forkhead, and GAS binding sites. Integration of data from our gestalt molecular analysis has defined a role for SOD2 in cellular proliferation, JAK/STAT signaling, and regulation of several transcription factors.
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PMID:Integrated molecular profiling of SOD2 expression in multiple myeloma. 1719 97

Bisphophonates (BP) were first named diphosphonates. They are potent inhibitors of osteoclastic activity and so reduce bone remodeling. Additionally they have anti-angiogenic properties and contribute to progressive disappearance of bony micro-vascular blood supply. Administrated orally, BP are generally used to prevent and treat osteoporosis. Injectable BP are used in patients with multiple myeloma and metastatic solid tumors. Scientific evidence dealing with a potentially devastating side effect of BP, osteochemonecrosis of the jaws, is growing rapidly. Clinical signs and symptoms include absent or delayed soft tissue healing with bony exposure following dental extraction or spontaneous gum dehiscence. Patients are usually asymptomatic but may develop pain if the bone becomes secondarily infected. At the beginning, no radiographic manifestations are seen, but in some cases a vast zone of necrotic bone can be seen on MRI, larger than what could be expected. Surgical debridements, bone curettage, local irrigation and or hyperbaric oxygen therapy have proven to be unsuccessful. Up to now, no definitive treatment strategy has been published to manage those patients leaving the dentist or the stomatologist resourceless. This article proposes recommendations for general practitioners, dentists, oral surgeons and designed for three types of patients: 1. patients to be treated with BP; 2. patients treated with BP without bisphosphonate-associated osteonecrosis; 3. patients with bisphosphonate-associated osteonecrosis. The proposed guidelines are not definitive and practitioners remain free to choose their treatment. Of upmost importance is to recognize the risks of oral complications before, during and after surgery in patients treated with BP and to inform them of such risks.
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PMID:[A proposed algorithm for medicodental care of patients treated with bisphosphonates]. 1719 96


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