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)

Permeabilized nuclei from mammalian cells encapsulated within agarose microbeads in an isotonic buffer are active in transcription and replication (Jackson, D. A., and P. R. Cook. 1985. EMBO (Eur. Mol. Biol. Organ.) J. 4:913-918). Their DNA is intact and the nuclei are accessible to macromolecules. Myeloma nuclei prepared in this way were used to probe the extent of DNA negative supercoiling and the effects of altering torsional strain by binding radioactively labeled monoclonal antibodies to Z-DNA. Control experiments used monoclonal antibodies against a nonhistone chromosomal protein, HMG-17. On increasing the amount of anti-HMG-17 added, a binding plateau was reached encompassing a 200-fold range of antibody concentration. On binding anti-Z-DNA antibody, a similar broad plateau of constant binding was found encompassing a 100-fold range of antibody concentration. The latter result was taken as a measure of preexisting Z-DNA in the nuclei. Additional anti-Z-DNA antibody binding can be "induced" in the presence of much higher concentration of antibody, apparently by perturbing the B-DNA/Z-DNA equilibrium. On inhibiting topoisomerase I with camptothecin, an elevated antibody binding plateau was found, suggesting that elastic torsional strain in the DNA is responsible for stabilizing the preexisting Z-DNA. This interpretation is supported by the fact that addition of small, nicking amounts of DNase I leads to a complete loss of antibody binding in the Z-DNA plateau region but not in the region of "induced" Z-DNA.
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PMID:The level of Z-DNA in metabolically active, permeabilized mammalian cell nuclei is regulated by torsional strain. 292 Dec 82

In order to clarify the mechanism of drug resistance in human myeloma cells, we investigated the expressions of DNA topoisomerase I and topoisomerase II gene and the genes possibly related to drug resistance; multi-drug resistant gene 1 (MDR-1), glutathione S-transferase class pi gene (GST-pi), by Northern blotting. Myeloma cells in eight of 15 cases prior to chemotherapy expressed topoisomerase I mRNA considerably, while the expression of topoisomerase II mRNA was detected weakly in only one of 16 myeloma patients. There was not any correlation between expression of topoisomerase I mRNA and clinical drug resistance. Significant expression of MDR-1 mRNA and P-glycoprotein was not detected in 25 cases of multiple myeloma prior to chemotherapy and even after several courses of VAD (vincristine, adriamycin and dexamethasone) therapy by Northern blotting and immunostaining using monoclonal anti-P-glycoprotein antibody (MRK-16), respectively. On the other hand, 16 of 21 myeloma cases showed significant expression of GST-pi protein and GST-pi mRNA with the various strengths, but there was no apparent correlation between GST-pi mRNA expression and clinical response. Therefore these data suggest that expression of the genes we tested may not determine the level of drug resistance in multiple myeloma, but lower or no significant expression of topoisomerase II mRNA in most myeloma cells indicates the possibility that topoisomerase II inhibitors such as VP-16 and topoisomerase II-mediated cytotoxic drugs such as adriamycin, are not so effective for the treatment of multiple myeloma.
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PMID:Expressions of DNA topoisomerase I and II gene and the genes possibly related to drug resistance in human myeloma cells. 809 26

The standard treatment of multiple myeloma is systemic chemotherapy. Despite 30 years of drug development in myeloma, there are no new drug regimens significantly superior to melphalan and prednisone. In addition, phase II studies of new drugs in myeloma have been disappointing, with low response rates and no prolongation in survival. The topoisomerase I (topo I) inhibitors are a new class of anticancer agents with a wide spectrum of activity in human malignancies. Recent evaluation of the topo I inhibitor topotecan demonstrated activity in advanced myeloma, suggesting a possible role for these drugs in the treatment of this disease. Further evaluation of the mechanisms of resistance to topo I inhibitors, study of combination therapy with topotecan, and evaluation of other topo I poisons in multiple myeloma is proposed.
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PMID:The use of topoisomerase I inhibitors in multiple myeloma. 977 80

Topotecan, a soluble semisynthetic derivative of camptothecin, is a specific inhibitor of topoisomerase I and is endowed of potent antiproliferative effect in vitro and in vivo on tumoral cell lines as well as on endothelial cells. Moreover, topotecan is able to interfere with the development of blood vessels in many in vivo experimental models. During the last years, several phase I clinical studies have demonstrated that the five-daily schedule is the most effective for the treatment of neoplastic diseases of children and adults. In particular, the best clinical results have been obtained in patients affected by metastatic ovarian cancer, small cell (SCLC) and non-small cell lung carcinoma (NSCLC), as well as mammary and gastrointestinal neoplasms. High response rates have been observed in myelodysplastic syndromes and myeloma. The clinical effectiveness of topotecan has been also demonstrated in ovarian carcinoma, even after failure of first or second line chemotherapy and in SCLC, where the response rate is 39%, while the percentage decreases up to 7% in case of drug resistance, with a median survival of 5.4 months. Toxicologic profile of topotecan is foreseeable and manageable, and the most frequent and severe toxicity is represented by myelosuppression. Leukopenia and neutropenia, which follow the administration of topotecan, are non-cumulative and self-limiting and unfrequently complicated by infections, whereas non-hematologic toxicities are uncommon and generally of mild-to-moderate degree. Topotecan is under continuous clinical evaluation for the treatment of neoplasms other than those reported above, alone or in combination with antineoplastic drugs in poly-chemotherapeutic protocols.
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PMID:[Preclinical pharmacology and clinical uses of topotecan]. 1078 94

Topotecan, a semi-synthetic derivative of the alkaloid camptothecin is an antitumor drug that like other camptothecin derivatives, targets DNA topoisomerase I, an enzyme that is present in cells in concentration relatively independent of the stage in the cell cycle. Topotecan stabilizes the complex formed between topoisomerase I and DNA, leading to DNA strand breakage and cell death. In accordance with preclinical studies, clinical efficacy of topotecan was documented in ovarian carcinoma, in small cell lung cancer and in childhood solid tumors. Myelosuppression is the dose-limiting toxicity and nonhematologic side effects are generally mild. The activity of topotecan against a number of hematological malignancies is now increasingly exploited as well as its role in high-dose chemotherapy programs with stem cell support. In both lymphoblastic and myeloid acute leukemias, topotecan has been widely utilised both as single agent or associated to other cytostatic drugs with proven efficacy in these diseases. Most of the published phase II studies demonstrated that heavily pre-treated, relapsing patients achieve a high percentage of overall responses with manageable toxicity. In myelodisplastic syndromes and acute myelomonocitic leukemias a recently published study shows positive results for the combination of topotecan and cytarabin. Topotecan seems to preferentially affect the abnormal cytogenetic clones and in patients achieving a complete response, a conversion from an aneuploid to a diploid karyotipe was documented. In non-Hodgkin lymphomas, several schedules have been tested in the phase I setting. When utilized alone and at very low dosage, the drug yielded 15% of objective responses and a lack of extrahematologic toxicity. Of particular interest seems to be the association of topotecan with taxanes that needs to be supported by growth factors. In multiple myeloma Topotecan has been utilized as single agent in heavily pre-treated patients. The obtained results show good activity and again myelosuppression as preminent toxicity. The use of topotecan in high-dose chemotherapy regimens for multiple myeloma has been proposed. The utilization of topotecan in high-dose chemotherapy is one of the newer and more interesting applications. Solid tumors (i.e. ovarian cancer and small cell lung cancer) are actually investigated by many authors, who have indicated that this drug can be used preferentially as a part of diversified programs containing overlimit dosages of different cytostatics. Furthermore, topotecan demonstrated to be an effective drug to mobilize CD34+ cells for autografting. A general conclusion is that topotecan is an interesting addition to the actual chemotherapy scenario, both because of its mechanism of action and its toxicity profile. The present review of the new possibility of utilization, give us the idea that topotecan has activity in several hematologic neoplasias; further investigations in these diseases (i.e., induction treatment, combination chemotherapy) are then warranted. The broad spectrum of antitumor activity and the characteristics of toxicity make it also interesting for use in both the circulating progenitor cell mobilization and in the consolidation phase of high-dose chemotherapy programs.
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PMID:[Topotecan: a new field of use]. 1078 97

The aim of this study was to assess the effect of systemic chemotherapy on the monoclonal protein levels of patients with solid tumors who also have a monoclonal gammopathy of undetermined significance (MGUS). All patients with solid tumors who were referred to our department for consideration of systemic chemotherapy were evaluated with serum protein electrophoresis (SPEP) for the presence of MGUS. When MGUS was confirmed with immunofixation, serial SPEP was performed during and after completion of chemotherapy. Over a 6-year period, 21 patients with solid tumors and MGUS were prospectively identified and assessed. At least 50% reduction of serum monoclonal protein was noted in 4 of 11 patients treated with paclitaxel or docetaxel with a platinum analogue and in 5 of 7 patients who received an irinotecan-containing regimen. Our data indicate that in MGUS patients treated with irinotecan-containing chemotherapy regimens, a high incidence of reduction in their monoclonal protein levels is observed. Since topotecan, another topoisomerase I inhibitor, has some activity in multiple myeloma, further evaluation of irinotecan may be warranted. Evaluation of larger numbers of MGUS patients treated with chemotherapy for their underlying malignancy may help identify "in vivo" potentially active agents and regimens for patients with overt myeloma.
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PMID:Monoclonal gammopathy of undetermined significance (MGUS) in patients with solid tumors: effects of chemotherapy on the monoclonal protein. 1527 96

Topoisomerase I inhibitors are effective anticancer therapies and have shown activity in hematologic malignancies. Here we show for the first time that SN38, the potent active metabolite of irinotecan, induces c-Jun NH(2)-terminal kinase activation, Fas up-regulation, and caspase 8-mediated apoptosis in multiple myeloma (MM) cells. Proteasomal degradation of nuclear topoisomerase I has been proposed as a resistance mechanism in solid malignancies. SN38-induced proteasomal degradation of topoisomerase I was observed during SN38-mediated cytotoxicity against MM.1S myeloma cell line but occurred after c-Jun NH(2)-terminal kinase activation, Fas up-regulation, and poly(ADP-ribose) polymerase cleavage and failed to protect cells from apoptosis. Differential toxicity was observed against MM cells versus bone marrow stromal cells, and SN38 inhibited adhesion-induced up-regulation of MM cell proliferation when MM cells adhere to bone marrow stromal cells. In addition, SN38 directly inhibited constitutive and inducible interleukin 6 and vascular endothelial growth factor secretion by bone marrow stromal cells. Synergy was observed when SN38 was used in combination with doxorubicin, bortezomib, as well as poly(ADP-ribose) polymerase inhibitor NU1025 and Fas-activator CH11. These findings have clinical significance, because identification of downstream apoptotic signaling after topoisomerase I inhibition will both elucidate mechanisms of resistance and optimize future combination chemotherapy against MM.
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PMID:Proteasomal degradation of topoisomerase I is preceded by c-Jun NH2-terminal kinase activation, Fas up-regulation, and poly(ADP-ribose) polymerase cleavage in SN38-mediated cytotoxicity against multiple myeloma. 1557 86

Inactivation of poly(ADP-ribose) polymerase-1 (PARP-1) has been shown to potentiate the cytotoxicity of distinct DNA targeting agents including topoisomerase I inhibitors. On the other hand, the PARP-1 deficient cells exhibited resistance to conventional inhibitors of topoisomerase II such as etoposide or doxorubicin (DOX). Recently, we observed the extreme sensitivity of PARP-1 knock-out (KO) cells to C-1305, a new biologically active triazoloacridone compound. C-1305 permanently arrested the cells in G2-phase of the cell-cycle. These observations prompted us to investigate more thoroughly the susceptibility of PARP-1 KO cells to DOX and to examine the effect of DOX on the progression of cell-cycle. We determined the uptake of DOX and P-glycoprotein (P-gp) expression in mouse cells and compared it with that in human myeloma 8226/Dox40 cells overexpressing P-gp. Exposure of mouse cells to DOX revealed a reduced drug uptake in cells lacking PARP-1. However, combined treatment with verapamil, a potent MDR modulator increased the DOX accumulation. Detailed immunoblotting experiments revealed an approximately threefold higher P-gp level in PARP-1 KO cells as compared with normal counterparts. Interestingly, DOX induced in normal fibroblasts very rapidly G2 arrest whereas in PARP-1 KO cells it blocked primarily the transition between S and G2 resulting in the increase of cells remaining in S-phase. This coincided with the lack of the site-specific phosphorylation of CDK2. Simultaneous inhibition of P-gp in cells lacking PARP-1 resulted in an accumulation of cells in G2. Exposure of mouse cells to high DOX dose activated significantly caspase-3/7 in PARP-1 KO cells.
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PMID:Major contribution of the multidrug transporter P-glycoprotein to reduced susceptibility of poly(ADP-ribose) polymerase-1 knock-out cells to doxorubicin action. 1586 98

Multiple myeloma (MM) remains an incurable disease and further development of novel agents is needed. Because constitutive expression of topoisomerase I (TopoI) in MM cells and the efficacy of SN-38, an active metabolite of irinotecan (CPT-11), have been reported, we investigated the therapeutic potential of CPT-11. Of the eight MM cell lines analyzed, four showed 50% inhibitory concentration values of less than 2 microg/mL for CPT-11 and less than 2 ng/mL for SN-38. This efficacy was partly explained by the high expression level of human carboxylesterase-2 (hCE-2) in MM cells. Interestingly, high expression of hCE-2 represented the nature of normal plasma cells, suggesting that hCE-2 could efficiently generate SN-38 within the plasma cells. As expected, higher sensitivity to CPT-11 was observed in hCE-2-overexpressing U266 cells than mock U266 cells. On the other hand, the expression levels of hCE-1, TopoI, UGT1A and ABCG2 did not seem to be associated with the sensitivity of MM cells to CPT-11. In a murine xenograft model inoculated s.c. with RPMI8226 cells, administration of CPT-11 alone significantly reduced the tumor volume. When a combination of CPT-11 and bortezomib was administered, the subcutaneous tumors completely disappeared. Thus, clinical trials on CPT-11 in patients with relapsed or refractory MM are warranted.
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PMID:Overexpression of carboxylesterase-2 results in enhanced efficacy of topoisomerase I inhibitor, irinotecan (CPT-11), for multiple myeloma. 1877 27

Objective Multiple myeloma (MM) is the second most common hematological cancer. An attempt to treat MM using a topoisomerase I inhibitor was made based on our previous non-clinical studies suggesting the usefulness of an SN-38 derivative. Our aim was to conduct a phase I/II study of NK012, a micelle-forming SN-38 conjugate, in patients with relapsed/refractory multiple myeloma (RRMM). Methods NK012 was administered at doses of 12-24 mg/m2 and the safety, pharmacokinetics and preliminary efficacy were evaluated. Results Neutropenia was the most common grade 3 or 4 adverse drug reaction. Grade 4 neutropenia accounted for the majority of dose-limiting toxicities and only appeared at a dose of 24 mg/m2. The maximum concentrations and the area under the concentration-time curves from time zero to infinity for both NK012 and its active metabolite SN-38 increased in a dose-dependent manner. The best overall response was stable disease, which was achieved in 12 out of 16 patients. Conclusion The recommended dose of NK012 monotherapy for RRMM patients was concluded to be 20 mg/m2. However, this phase I/II study was terminated at the end of the phase I stage because no patients showed an objective response. Additional clinical studies of combination therapy with NK012 and other agents are warranted.
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PMID:A Phase I/II Study for Dose-finding, and to Investigate the Safety, Pharmacokinetics and Preliminary Efficacy of NK012, an SN-38-Incorporating Macromolecular Polymeric Micelle, in Patients with Multiple Myeloma. 2922 63


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