Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:5.99.1.3 (topoisomerase)
 9,911 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The present study assessed the role of adenoviral vector-mediated wild-type p53 gene transfer in B lymphoma cells. Deficiency of p53-mediated cell death is common in human cancer contributing to both tumorigenesis and chemoresistance. Lymphoma cells are being considered as suitable targets for gene therapy protocols. Recently, we reported an adenoviral protocol leading to highly efficient gene transfer to B lymphoma cells. All lymphoma cell lines (n=5) tested here showed mutations in the p53 gene locus. The aim of this work was to transduce lymphoma cells with the wild-type p53 gene. Using this protocol, 88% of Raji, 75% of Daudi, and 45% of OCI-Ly8-LAM53 cells were transfected with the reporter gene green fluorescent protein at a multiplicity of infection of 200. The expression of green fluorescent protein in CA46 and BL41 cells was 27% and 42%, respectively. At this multiplicity of infection, growth characteristics of lymphoma cell lines were not changed significantly. In contrast, cells transduced with wild-type p53 gene showed an inhibition of proliferation as well as an increase in apoptosis. Cell loss by apoptosis after p53 gene transfer was up to 40% as compared to transduction with an irrelevant vector. In addition, we determined the effects of DNA damage produced by the DNA topoisomerase II inhibitor etoposide on wild-type p53 transfected lymphoma cells. In Ad-p53-transfected Raji cells, treatment with the drug resulted in a marked increase of cell loss in comparison to Ad-beta-Gal-transfected cells (45% vs. 77%). Interestingly, performing cytotoxicity studies, we could show an increased sensitivity of Raji and Daudi cells against immunological effector cells. In conclusion, transduction of wild-type p53 into lymphoma cells expressing mutated p53 was efficient and led to inhibition of proliferation and increase in apoptotic rate in some cell lines dependent on p53 mutation. This protocol should have an impact on the use of lymphoma cells in cancer gene therapy protocols.
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PMID:Effects of adenoviral wild-type p53 gene transfer in p53-mutated lymphoma cells. 1149 63

p38 MAPK is mainly activated by stress stimuli and mediates signals that regulate various cellular responses, including cell-cycle progression and apoptosis, depending on cell types and stimuli. Here we examine the role of p38 in regulation of apoptosis and cell cycle checkpoint in Daudi B-cell lymphoma cells treated with the topoisomerase II inhibitor etoposide. Etoposide activated p38, inhibited the G2/M transition with the persistent inhibitory phosphorylation of Cdc2 on Tyr15, and caused apoptosis of Daudi cells. Inducible expression of a dominant negative p38alpha mutant in Daudi cells reduced the inhibition of Cdc2 as well as G2/M arrest and augmented apoptosis induced by etoposide. SB203580, a specific inhibitor of p38alpha and p38beta, similarly reduced the inhibitory phosphorylation of Cdc2 as well as G2/M arrest and augmented apoptosis of Daudi cells treated with etoposide. These results suggest that p38 plays a role in G2/M checkpoint activation through induction of the persistent inhibitory phosphorylation of Cdc2 and, thereby, inhibits apoptosis of Daudi cells treated with etoposide. The present study, thus, raises the possibility that p38 may represent a new target for sensitization of lymphoma cells to DNA-damaging chemotherapeutic agents.
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PMID:p38 MAP kinase plays a role in G2 checkpoint activation and inhibits apoptosis of human B cell lymphoma cells treated with etoposide. 1615 44

A functional relationship between the apoptotic endonuclease DNAS1L3 and the chemotherapeutic drug VP-16 was established. The lymphoma cell line, Daudi, exhibited a significant resistance to VP-16 treatment in comparison to the lymphoma/leukemia cell line, U-937. While U-937 cells degraded their DNA into internucleosomal fragments, Daudi cells failed to undergo such fragmentation in response to the drug. Activation of both caspase-3 and DNA fragmentation factor was not sufficient to trigger internucleosomal DNA fragmentation in Daudi cells. No correlation was found between expression levels of topoisomerase-II, Pgp, Bcl-2, Bax, or Bad and decreased sensitivity of Daudi cells to VP-16. Daudi cells failed to express DNAS1L3 and ectopic expression of this protein significantly sensitized the cells to VP-16. An enhancement of caspase-3 activity and collapse of mitochondrial membrane potential underlie DNAS1L3-mediated sensitization of Daudi cells to VP-16, which may be a direct result of DNAS1L3-mediated increase in PARP-1-activating DNA breaks after VP-16 treatment. Our results suggest that DNAS1L3 plays an active role in lymphoma cell sensitization to VP-16 and that its deficiency may constitute a novel mechanism of drug resistance in these cells.
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PMID:Correlation between decreased sensitivity of the Daudi lymphoma cells to VP-16-induced apoptosis and deficiency in DNAS1L3 expression. 1642 1

CPT-11, a derivative of camptothecin (CPT) that interacts with type-I DNA topoisomerase, induced apoptosis in HL60 and Daudi cells in vitro. This cytotoxic activity was time and dose dependent, and was prevented by cycloheximide (CHX), a protein synthesis inhibitor, indicating the requirement of new protein synthesis for CPT-11-induced apoptotic cell death. Ac-Tyr-Val-Ala-Asp-aldehyde (YVAD) and Ac-Asp-Glu-Val-Asp-aldehyde (DEVD), synthesized tetrapeptide inhibitors of interleukin(1beta)-converting enzyme (ICE)- and CPP32/Yama-like proteases, were used to examine the CPT-11-induced death signal transduction. These inhibitors blocked CPT-11-induced cytotoxicity in a time- and dose-dependent manner. Cytotoxic activity of SN-38, an active metabolite of CPT-11, was about 1000-fold that of CPT-11 and was also prevented by CHX, YVAD and DEVD. The doses of YVAD, however, were a little too high; the prevention by YVAD is then thought to be non-specific. In addition, lymphocytes obtained from normal and lpr(cg) mutant mice showed similar susceptibility to CPT-11 cytotoxicity. These results indicate the direct involvement of CPP32/Yama-like protease in the CPT-11-induced death signal transduction pathway, and no involvement of Fas antigen in the pathway.
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PMID:Involvement of CPP32/Yama-like protease in CPT-11-induced death signal transduction pathway. 2065 Feb 53

Interleukin-24 (IL-24) is a cytokine encoded by a tumor suppressor gene of the IL-10 family, also known as the melanoma differentiation associated gene-7 (Mda-7) and first discovered in human melanoma cells. Mda-7/IL-24 has been shown to inhibit the proliferation of various human tumor cell lines, but its effect on the sensitivity of B cell lymphoma to chemotherapy agents is not yet clear. The present study investigated the effects of Mda-7/IL-24 overexpression on the sensitivity of human B cell lymphoma cells to chemotherapy, as well as its mechanism of action. The sensitivity of stable Mda-7/IL-24 overexpressing Raji and Daudi cells to cis-diamminedichloroplatinum (CDDP), epirubicin and vinblastine (VCR) were assessed by the MTS method, and the IC50 value calculated. Cell apoptosis and the intracellular accumulation of Rhodamine-123 were assayed by flow cytometry. The expression of multidrug resistance gene 1 (MDR1), B-cell-specific Moloney murine leukemia virus insertion site 1 (BMI1), topoisomerase II (Topo II) and multidrug resistance-related protein 1 (MRP1) mRNA and protein were analyzed by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blotting, respectively. In addition, western blot analysis was also used to investigate the effect of Mda-7/IL-24 on activity of GTP-RhoA-ERK signaling pathway in Raji and Daudi cells. Growth inhibition and apoptosis rates of Mda-7/IL-24 overexpressing Raji and Daudi cells were higher than those of non-transfected cells and cells transfected with vector alone when treated with CDDP, epirubicin and VCR. The IC50 values of CDDP, epirubicin and VCR were lower for Mda-7/IL-24-overexpressing Raji and Daudi cells than for non-transfected cells and cells transfected with empty vector. Intracellular accumulation of Rhodamine-123 and the expression of Topo II were higher, while the levels of MDR1, BMI and MRP1 mRNA and protein were lower, in Mda-7/IL-24 overexpressing Raji and Daudi cells. Furthermore, the activities of GTP-RhoA-ERK signaling pathway in Raji and Daudi cells were suppressed. These results indicated that Mda-7/IL-24 enhanced the sensitivity of B lymphoma cells to chemotherapy agents by altering the expression of multidrug-resistance genes via downregulating GTP-RhoA-ERK signaling pathway, suggesting that treatment of B cell lymphomas with Mda-7/IL-24 could avoid MDR.
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PMID:Mda-7/IL-24 enhances sensitivity of B cell lymphoma to chemotherapy drugs. 2688 73