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Peleg R, Romzova M, Kogan-Zviagin I, Apte RN, Priel E. Modification of topoisomerases in mammospheres derived from breast cancer cell line: clinical implications for combined treatments with tyrosine kinase inhibitors. BMC Cancer 2014; 14:910. [PMID: 25472619 PMCID: PMC4289278 DOI: 10.1186/1471-2407-14-910] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 11/25/2014] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Accumulating evidences suggest that tumors are driven by a small population of cells, termed "cancer stem cells" (CSCs), which may be resistant to current therapeutic approaches. In breast carcinoma, the CSCs have been identified as a CD44+/CD24- cell population. These rare cells are able to grow as non-adherent sphere-like structures, termed "mammospheres", which enables their isolation and expansion in culture. To design efficient strategies for the complete eradication of CSCs, it is important to identify enzymes and proteins that are known as anti-cancer targets, and differ in their properties from those present in the none CSCs. Here we investigated the activity and expression of type I and type II DNA topoisomerases (topo I and topo II) in CSCs and their response to anti-topoisomerase inhibitors. METHODS MCF7 breast cancer cells, PC3 prostate cancer cells and 4 T1-Luc-Oct3/4pG mouse mammary carcinoma cells were grown on low-attachment dishes in specific medium and allowed to form spheres. Enrichment of CSC population was verified by immunostaining, flow cytometry or fluorescent microscopy imaging. Nuclear protein extracts were prepared and topoisomerases activity and protein levels were determined. Cell viability was examined by the MTT and Neutral Red assays. RESULTS Unlike the adherent MCF7 cell line, topo I activity is decreased and topo II activity is increased in the CSCs. However, the relative levels of the enzyme proteins were similar in both mammospheres and adherent cells. Topo I activity in mammospheres is regulated, at least in part, by PARP-1, as observed by the recovery of topo I activity after treatment with PARP-1 inhibitor 3-Aminobenzamide. Mammosphere-derived cells show reduced sensitivity to topo I inhibitor, camptothecin, and increased sensitivity to topo II inhibitor etoposide. Intact mammospheres show increased resistance to both drugs. A combined treatment of intact mammospheres with either CPT and gefitinib, or etoposide and erlotinib, increased the anti-cancer effect of both drugs. CONCLUSIONS The data of this study suggest that the understanding of biological behavior of essential enzymes such as topoisomerases, in CSCs' progression and early stages of tumor development, is important for developing new strategies for cancer treatment as well as new therapies for advanced disease.
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Affiliation(s)
| | | | | | | | - Esther Priel
- The Shraga Segal Department of Microbiology, Immunology & Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel.
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2
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Park ES, Kang SI, Yoo KD, Lee MY, Yoo HS, Hong JT, Shin HS, Kim B, Yun YP. Camptothecin inhibits platelet-derived growth factor-BB-induced proliferation of rat aortic vascular smooth muscle cells through inhibition of PI3K/Akt signaling pathway. Exp Cell Res 2013; 319:982-91. [PMID: 23328306 DOI: 10.1016/j.yexcr.2012.12.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 12/27/2012] [Accepted: 12/29/2012] [Indexed: 11/26/2022]
Abstract
The abnormal proliferation of vascular smooth muscle cells (VSMCs) in arterial wall is a major cause of vascular disorders such as atherosclerosis and restenosis after angioplasty. In this study, we investigated not only the inhibitory effects of camptothecin (CPT) on PDGF-BB-induced VSMC proliferation, but also its molecular mechanism of this inhibition. CPT significantly inhibited proliferation with IC50 value of 0.58 μM and the DNA synthesis of PDGF-BB-stimulated VSMCs in a dose-dependent manner (0.5-2 μM ) without any cytotoxicity. CPT induced the cell cycle arrest at G0/G1 phase. Also, CPT decreased the expressions of G0/G1-specific regulatory proteins including cyclin-dependent kinase (CDK)2, cyclin D1 and PCNA in PDGF-BB-stimulated VSMCs. Pre-incubation of VSMCs with CPT significantly inhibited PDGF-BB-induced Akt activation, whereas CPT did not affect PDGF-receptor beta phosphorylation, extracellular signal-regulated kinase (ERK) 1/2 phosphorylation and phospholipase C (PLC)-γ1 phosphorylation in PDGF-BB signaling pathway. Our data showed that CPT pre-treatment inhibited VSMC proliferation, and that the inhibitory effect of CPT was enhanced by LY294002, a PI3K inhibitor, on PDGF-BB-induced VSMC proliferation. In addition, inhibiting the PI3K/Akt pathway by LY294002 significantly enhanced the suppression of PCNA expression and Akt activation by CPT. These results suggest that the anti-proliferative activity of CPT is mediated in part by downregulating the PI3K/Akt signaling pathway.
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Affiliation(s)
- Eun-Seok Park
- Department of Applied Biochemistry, Division of Life Science, College of Health and Biomedical Science, Konkuk University, Chungju, Chungbuk, South Korea
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3
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DNA-Binding and Topoisomerase-I-Suppressing Activities of Novel Vanadium Compound Van-7. Bioinorg Chem Appl 2012; 2012:756374. [PMID: 23055949 PMCID: PMC3465879 DOI: 10.1155/2012/756374] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 08/17/2012] [Accepted: 08/17/2012] [Indexed: 11/18/2022] Open
Abstract
Vanadium compounds were studied during recent years to be considered as a representative of a new class of nonplatinum metal anticancer agents in combination to its low toxicity. Here, we found a vanadium compound Van-7 as an inhibitor of Topo I other than Topo II using topoisomerase-mediated supercoiled DNA relaxation assay. Agarose gel electrophoresis and comet assay showed that Van-7 treatment did not produce cleavable complexes like HCPT, thereby suggesting that Topo I inhibition occurred upstream of the relegation step. Further studies revealed that Van-7 inhibited Topo I DNA binding involved in its intercalating DNA. Van-7 did not affect the catalytic activity of DNase I even up to100 μM. Van-7 significantly suppressed the growth of cancer cell lines with IC(50) at nanomolar concentrations and arrested cell cycle of A549 cells at G2/M phase. All these results indicate that Van-7 is a potential selective Topo I inhibitor with anticancer activities as a kind of Topo I suppressor, not Topo I poison.
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4
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Cha DS, Hollis SE, Datla US, Lee S, Ryu J, Jung HR, Kim E, Kim K, Lee M, Li C, Lee MH. Differential subcellular localization of DNA topoisomerase-1 isoforms and their roles during Caenorhabditis elegans development. Gene Expr Patterns 2012; 12:189-95. [PMID: 22452997 DOI: 10.1016/j.gep.2012.03.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2011] [Revised: 03/03/2012] [Accepted: 03/11/2012] [Indexed: 10/28/2022]
Abstract
DNA topoisomerase-1 (TOP-1) resolves the topological problems associated with DNA replication, transcription and recombination by introducing temporary single-strand breaks in the DNA. Caenorhabditis elegans TOP-1 has two isoforms, TOP-1α and TOP-1β. TOP-1β is broadly localized to the nuclei of many cells at all developmental stages and concentrated in nucleoli in embryo gut and oogenic cells. However, TOP-1α is specifically localized to centrosomes, neuronal cells, excretory cells and chromosomes of germ cells in embryonic and larval stages. Reporter gene analysis also shows that top-1 transcription is highly activated in several sensory neurons, speculating the possible role of TOP-1α in neuronal development. From RNA interference (RNAi) experiments, we demonstrated that C. elegans TOP-1 is required for chromosomal segregation, germline proliferation and gonadal migration, which are all correlated with the expression and activity of TOP-1. Therefore, our findings may provide an insight into a new role of TOP-1 in development of multicellular organisms.
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Affiliation(s)
- Dong Seok Cha
- Division of Hematology/Oncology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
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5
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Goswami A, Qiu S, Dexheimer TS, Ranganathan P, Burikhanov R, Pommier Y, Rangnekar VM. Par-4 binds to topoisomerase 1 and attenuates its DNA relaxation activity. Cancer Res 2008; 68:6190-8. [PMID: 18676842 DOI: 10.1158/0008-5472.can-08-0831] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The regulation of DNA relaxation by topoisomerase 1 (TOP1) is essential for DNA replication, transcription, and recombination events. TOP1 activity is elevated in cancer cells, yet the regulatory mechanism restraining its activity is not understood. We present evidence that the tumor suppressor protein prostate apoptosis response-4 (Par-4) directly binds to TOP1 and attenuates its DNA relaxation activity. Unlike camptothecin, which binds at the TOP1-DNA interface to form cleavage complexes, Par-4 interacts with TOP1 via its leucine zipper domain and sequesters TOP1 from the DNA. Par-4 knockdown by RNA interference enhances DNA relaxation and gene transcription activities and promotes cellular transformation in a TOP1-dependent manner. Conversely, attenuation of TOP1 activity either by RNA interference or Par-4 overexpression impedes DNA relaxation, cell cycle progression, and gene transcription activities and inhibits transformation. Collectively, our findings suggest that Par-4 serves as an intracellular repressor of TOP1 catalytic activity and regulates DNA topology to suppress cellular transformation.
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Affiliation(s)
- Anindya Goswami
- Department of Radiation Medicine, Graduate Center for Toxicology, University of Kentucky, Lexington, Kentucky 40536, USA
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6
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Ricart AD, Hammond LA, Kuhn JG, Takimoto CH, Goetz A, Forouzesh B, Forero L, Ochoa-Bayona JL, Berg K, Tolcher AW, Rowinsky EK. Phase I and Pharmacokinetic Study of Sequences of the Rebeccamycin Analogue NSC 655649 and Cisplatin in Patients with Advanced Solid Tumors. Clin Cancer Res 2005; 11:8728-36. [PMID: 16361560 DOI: 10.1158/1078-0432.ccr-05-1572] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE To evaluate the feasibility of administering NSC 655649, a water-soluble rebeccamycin analogue that inhibits both topoisomerases I and II, in combination with cisplatin (CDDP) in adults with solid malignancies. Major toxicologic and pharmacologic differences between the two sequences of drug administration were also assessed. EXPERIMENTAL DESIGN NSC 655649 was administered as a 60-minute i.v. infusion; CDDP was given i.v. before or after NSC 655649 on day 1. Each patient was treated with alternating drug sequences every 3 weeks; doses of each drug were escalated in separate cohorts of new patients. Sequential dose escalation of NSC 655649 or CDDP resulted in three dosage permutations of NSC 655649/CDDP: 440/50, 550/50, and 440/75 mg/m2. After the maximum tolerated dose level was determined, the feasibility of using granulocyte colony-stimulating factor to permit further dose escalation was explored. RESULTS Twenty patients were treated with 70 courses of NSC 655649/CDDP. Myelosuppression was the principal toxicity. The incidence of severe neutropenia, often associated with severe thrombocytopenia, was unacceptably high in minimally pretreated patients at the NSC 655649/CDDP dose level of 550/50 mg/m2 without and with granulocyte colony-stimulating factor. Major pharmacokinetic interactions between NSC 655649 and CDDP were not apparent. No relevant sequence-dependent differences in toxicity or pharmacokinetic variables occurred. Three patients had partial responses. CONCLUSIONS NSC 655649 and CDDP were well tolerated by minimally pretreated subjects at 440 and 50 mg/m2, respectively. Neither pharmacokinetic interactions between the agents nor sequence-dependent toxicologic or pharmacokinetic effects were apparent. The tolerance and preliminary activity observed with this combination suggest that disease-directed evaluations of the regimen are warranted.
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Affiliation(s)
- Alejandro D Ricart
- Institute for Drug Development, Cancer Therapy and Research Center, and Department of Pharmacology, University of Texas Health Science Center at San Antonio 78229, USA.
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7
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Engel R, Valkov NI, Gump JL, Hazlehurst L, Dalton WS, Sullivan DM. The cytoplasmic trafficking of DNA topoisomerase IIalpha correlates with etoposide resistance in human myeloma cells. Exp Cell Res 2004; 295:421-31. [PMID: 15093741 DOI: 10.1016/j.yexcr.2004.01.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2003] [Revised: 01/08/2004] [Indexed: 10/26/2022]
Abstract
In this study we have investigated the role of topoisomerase (topo) IIalpha trafficking in cellular drug resistance. To accomplish this, it was necessary to separate the influence of cell cycle, drug uptake, topo protein levels, and enzyme trafficking on drug sensitivity. Thus, we developed a cell model (called accelerated plateau) using human myeloma H929 cells that reproducibly translocates topo IIalpha to the cytoplasm. Compared to log-phase cells, the cytoplasmic redistribution of topo IIalpha in plateau-phase cells correlated with a 10-fold resistance to VP-16 and a 40-60% reduction in the number of drug-induced double-strand DNA breaks. In addition, 7-fold more VP-16 was necessary to achieve 50% topo IIalpha band depletion, suggesting that there are fewer drug-induced topo-DNA complexes formed in quiescent cells than in log-phase cells. The total cellular amount of topo IIalpha and topo IIbeta protein in log- and plateau-phase cells was similar as determined by Western blot analysis. There was a 25% reduction in S-phase cell number in plateau cells (determined by bromodeoxyuridine (BrdU) incorporation), while there was no significant difference in the equilibrium concentrations of [(3)H]-VP-16 when log cells were compared with plateau cells. Furthermore, the nuclear/cytoplasmic ratio of topo IIalpha is increased 58-fold in accelerated-plateau H929 cells treated with leptomycin B (LMB) when compared to untreated cells. It appears that the nuclear-cytoplasmic shuttling of topo IIalpha, which decreases the amount of nuclear target enzyme, is a major mechanism of drug resistance to topo II inhibitors in plateau-phase myeloma cells.
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MESH Headings
- Antibiotics, Antineoplastic/pharmacokinetics
- Antibiotics, Antineoplastic/therapeutic use
- Antineoplastic Agents/pharmacokinetics
- Antineoplastic Agents/therapeutic use
- Antineoplastic Agents, Phytogenic/pharmacokinetics
- Antineoplastic Agents, Phytogenic/therapeutic use
- Blotting, Western
- Cell Line, Tumor
- Cell Nucleus/enzymology
- Comet Assay
- Cytoplasm/enzymology
- DNA Topoisomerases, Type II/drug effects
- DNA Topoisomerases, Type II/genetics
- DNA Topoisomerases, Type II/metabolism
- Drug Resistance, Neoplasm
- Electrophoresis, Gel, Two-Dimensional
- Etoposide/pharmacokinetics
- Etoposide/therapeutic use
- Fatty Acids, Unsaturated/pharmacokinetics
- Fatty Acids, Unsaturated/therapeutic use
- Flow Cytometry
- HL-60 Cells
- Humans
- Microscopy, Fluorescence
- Mitoxantrone/pharmacokinetics
- Mitoxantrone/therapeutic use
- Multiple Myeloma/drug therapy
- Multiple Myeloma/enzymology
- Plasmacytoma/drug therapy
- Plasmacytoma/enzymology
- Protein Transport
- Subcellular Fractions
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Affiliation(s)
- Roxane Engel
- Experimental Therapeutics Program, Departments of Interdisciplinary Oncology and Biochemistry and Molecular Biology, H. Lee Moffitt Cancer Center and Research Institute, University of South Florida, Tampa, FL 33612, USA
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8
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Tolcher AW, Eckhardt SG, Kuhn J, Hammond L, Weiss G, Rizzo J, Aylesworth C, Hidalgo M, Patnaik A, Schwartz G, Felton S, Campbell E, Rowinsky EK. Phase I and pharmacokinetic study of NSC 655649, a rebeccamycin analog with topoisomerase inhibitory properties. J Clin Oncol 2001; 19:2937-47. [PMID: 11387367 DOI: 10.1200/jco.2001.19.11.2937] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PURPOSE To assess the feasibility of administering NSC 655649, a water-soluble, rebeccamycin analog with topoisomerase inhibitory properties, as a brief intravenous (IV) infusion once every 3 weeks and to determine the maximum-tolerated dose (MTD) of NSC 655649, characterize its pharmacokinetic behavior, and seek preliminary evidence of antitumor activity. PATIENTS AND METHODS Patients with advanced solid malignancies were treated with escalating doses of NSC 655649 administered over 30 to 60 minutes IV once every 3 weeks. An accelerated dose-escalation method was used to guide dose escalation. After three patients were treated at the first dose level, doses were escalated in increments that ranged up to 150% using single patient cohorts until moderate toxicity was observed, when a more conservative dose-escalation scheme was invoked. MTD was defined as the highest dose level at which the incidence of dose-limiting toxicity did not exceed 20%. MTD was determined for both minimally pretreated (MP) and heavily pretreated (HP) patients. Plasma and urine were sampled to characterize the pharmacokinetic and excretory behavior of NSC 655649. RESULTS Forty-five patients were treated with 130 courses of NSC 655649 at doses ranging from 20 mg/m(2) to 744 mg/m(2). Myelosuppression was the principal toxicity. Severe neutropenia, which was often associated with thrombocytopenia, was unacceptably high in HP and MP patients treated at 572 mg/m(2) and 744 mg/m(2), respectively. Nausea, vomiting, and diarrhea were common but rarely severe. The pharmacokinetics of NSC 655649 were dose dependent and fit a three-compartment model. The clearance and terminal elimination half-lives for NSC 655649 averaged 7.57 (SD = 4.2) L/h/m(2) and 48.85 (SD = 23.65) hours, respectively. Despite a heterogeneous population of MP and HP patients, the magnitude of drug exposure correlated well with the severity of myelosuppression. Antitumor activity was observed in two HP ovarian cancer patients and one patient with a soft tissue sarcoma refractory to etoposide and doxorubicin. CONCLUSION Recommended phase II doses are 500 mg/m(2) and 572 mg/m(2) IV once every 3 weeks for HP and MP patients, respectively. The absence of severe nonhematologic toxicities, the encouraging antitumor activity in HP patients, and the unique mechanism of antineoplastic activity of NSC 655649 warrant further clinical development.
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Affiliation(s)
- A W Tolcher
- Institute for Drug Development, Cancer Therapy and Research Center, San Antonio, Texas 78229, USA.
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9
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Brehm BR, Bock C, Wesselborg S, Pfeiffer S, Schüler S, Schulze-Osthoff K. Prevention of human smooth muscle cell proliferation without induction of apoptosis by the topoisomerase I inhibitor topotecan. Biochem Pharmacol 2001; 61:119-27. [PMID: 11137716 DOI: 10.1016/s0006-2952(00)00514-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Despite significant improvements in the treatment of atherosclerotic disease involving procedures such as angioplasty, bypass grafting, endartherectomy, or stent implantation, secondary failure due to late restenosis still occurs in 30-50% of individuals. Restenosis and later stages of atherosclerotic lesions arise from a complex series of fibroproliferative responses to vascular injury that are triggered by potent growth-regulatory molecules and finally result in vascular smooth muscle cell proliferation, migration, and neointima formation. The aim of this study was to investigate the antiproliferative effects of the topoisomerase I inhibitor topotecan on human arterial coronary smooth muscle cells. Following incubation of cells with different drug concentrations, mitotic indices were measured by bromodeoxyuridine incorporation, while cellular mitochondrial activity was evaluated using the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test. Continuous incubation with topotecan for 7 days resulted in a complete and dose-dependent reduction of smooth muscle cell proliferation, and topotecan inhibited cell proliferation in the presence of growth factors as well. In contrast, mitochondrial activity was only partially decreased. Remarkably, although even short-term incubations for 20 min were sufficient to induce a long-lasting growth inhibition, topotecan did not induce apoptosis. Our results therefore suggest that, based on its drug profile, the topoisomerase I inhibitor topotecan may be a promising drug to inhibit restenosis occurring after coronary angioplasty with local devices.
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Affiliation(s)
- B R Brehm
- Department of Cardiology, University of Tübingen, Tübingen, Germany
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10
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Valkov NI, Gump JL, Engel R, Sullivan DM. Cell density-dependent VP-16 sensitivity of leukaemic cells is accompanied by the translocation of topoisomerase IIalpha from the nucleus to the cytoplasm. Br J Haematol 2000; 108:331-45. [PMID: 10691864 DOI: 10.1046/j.1365-2141.2000.01832.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The resistance of several leukaemic and myeloma cell lines (CCRF, L1210, HL-60, KG-1a and RPMI 8226) to VP-16 was found to increase with cell density and to be maximal (3.5- to 39-fold) in plateau phase cell cultures, as measured by clonogenic and MTT assays. Non-transformed confluent Flow 2000 human fibroblasts and Chinese hamster ovary (CHO) cells were also five- and 15-fold resistant to VP-16 respectively. The transition from log to plateau phase was accompanied by a drastic decrease in topoisomerase (topo) IIalpha content in CHO cells and human fibroblasts, while the leukaemic cells maintained constant cellular levels of topo IIalpha and topo IIbeta. However, the nuclear topo IIalpha content was found to decrease as a result of translocation of the enzyme to the cytoplasmic compartment in the leukaemic cells. This was confirmed by subcellular fractionation experiments, Western blotting analyses and immunocytochemistry studies. The quantity of topo IIalpha in plateau phase cytoplasmic fractions ranged from 18% in L1210 cells to 50% in HL-60 and 8226 cells, as measured by both immunoblotting and quantification of the label in immunofluorescent images. The cytoplasmic fraction from plateau phase cells retained topo II catalytic activity, as measured by the decatenation of kinetoplast DNA. The nuclear-cytoplasmic ratio of topo IIalpha may be critical in determining the sensitivity of leukaemic cells to topo II inhibitors. Cytoplasmic trafficking of topo IIalpha was observed in plasma cells obtained from patients with multiple myeloma, and perhaps contributes to drug resistance in this disease.
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Affiliation(s)
- N I Valkov
- Department of Internal Medicine, H. Lee Moffitt Cancer Center and Research Institute, University of South Florida, Tampa, FL 33612, USA
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11
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Tosh K, Cheesman S, Horrocks P, Kilbey B. Plasmodium falciparum: stage-related expression of topoisomerase I. Exp Parasitol 1999; 91:126-32. [PMID: 9990340 DOI: 10.1006/expr.1998.4362] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The expression and activity of topoisomerase I (PfTopoI) has been examined during the intraerythrocytic stages of the Plasmodium falciparum life cycle. The promoter is inactive during the early ring stage and becomes active only during the later trophozoite and schizont stages. The PfTOP1 transcript starts to accumulate in the trophozoite stage parasite, decreasing again in the schizont stage. Using both stage-specific Western analysis and immunofluorescent assays we show that PfTopoI is present at low levels in rings and accumulates to approximately equal levels in the trophozoite and schizont stages. Experiments to determine the activity of PfTopoI, using a topoisomerase I relaxation assay, show that there is a low level of PfTopoI activity in both ring and trophozoite stages, but activity increases dramatically in the schizont stage. The PfTopoI activity can be inhibited by treatment with specific antiserum and by the type I topoisomerase-specific inhibitor camptothecin.
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MESH Headings
- Animals
- Antibodies, Protozoan/chemistry
- Blotting, Northern
- Blotting, Western
- Camptothecin/pharmacology
- DNA Topoisomerases, Type I/genetics
- DNA Topoisomerases, Type I/metabolism
- DNA, Protozoan/chemistry
- Electrophoresis, Agar Gel
- Electrophoresis, Polyacrylamide Gel
- Enzyme Inhibitors/pharmacology
- Fluorescent Antibody Technique
- Gene Expression Regulation, Enzymologic
- Malaria, Falciparum/enzymology
- Malaria, Falciparum/parasitology
- Nucleic Acid Hybridization
- Plasmodium falciparum/drug effects
- Plasmodium falciparum/enzymology
- Plasmodium falciparum/genetics
- Promoter Regions, Genetic/physiology
- Rabbits
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Affiliation(s)
- K Tosh
- Institute of Cell and Molecular Biology, University of Edinburgh, United Kingdom
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12
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Hashimoto S, Jing Y, Kawazoe N, Masuda Y, Nakajo S, Yoshida T, Kuroiwa Y, Nakaya K. Bufalin reduces the level of topoisomerase II in human leukemia cells and affects the cytotoxicity of anticancer drugs. Leuk Res 1997; 21:875-83. [PMID: 9393603 DOI: 10.1016/s0145-2126(97)00061-1] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
When human leukemia HL-60 cells were treated with 10(-7) M bufalin, the amounts of both topoisomerase (topo) II alpha and II beta and the activity of topo II decreased markedly and were almost undetectable 18 h after the start of treatment. The level of topo II mRNA started to decrease immediately after the start of treatment with bufalin, with a subsequent decrease in the amount of topo II alpha protein. These changes preceded the fragmentation of DNA, a typical feature of apoptosis. The results suggest that bufalin caused a marked decrease in the steady-state level of topo II alpha mRNA, which led to a decrease in the amount and activity of the enzyme and to the induction of apoptosis. A reduction in the level of topo II alpha by bufalin was also observed in other lines of human leukemia cells such as ML1 and U937. The results were exploited to potentiate the effects of cisplatin and retinoic acid (RA) on HL-60 cells: pretreatment of HL-60 cells with 10(-7) M bufalin for 6 h increased the inhibitory effects of cisplatin and RA on cell growth and enhanced the induction of cell death.
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Affiliation(s)
- S Hashimoto
- Laboratory of Biological Chemistry, School of Pharmaceutical Sciences, Showa University, Tokyo, Japan
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13
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Meyer KN, Kjeldsen E, Straub T, Knudsen BR, Hickson ID, Kikuchi A, Kreipe H, Boege F. Cell cycle-coupled relocation of types I and II topoisomerases and modulation of catalytic enzyme activities. J Biophys Biochem Cytol 1997; 136:775-88. [PMID: 9049244 PMCID: PMC2132491 DOI: 10.1083/jcb.136.4.775] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
We visualized DNA topoisomerases in A431 cells and isolated chromosomes by isoenzyme-selective immunofluorescence microscopy. In interphase, topoisomerase I mainly had a homogeneous nuclear distribution. 10-15% of the cells exhibited granular patterns, 30% showed bright intranucleolar patches. Topoisomerase II isoenzymes showed spotted (alpha) or reticular (beta) nuclear patterns throughout interphase. In contrast to topoisomerase IIalpha, topoisomerase IIbeta was completely excluded from nucleoli. In mitosis, topoisomerase IIbeta diffused completely into the cytosol, whereas topoisomerases I and IIalpha remained chromosome bound. Chromosomal staining of topoisomerase I was homogeneous, whereas topoisomerase IIalpha accumulated in the long axes of the chromosome arms and in the centriols. Topoisomerase antigens were 2-3-fold higher in mitosis than in interphase, but specific activities of topoisomerase I and II were reduced 5- and 2.4-fold, respectively. These changes were associated with mitotic enzyme hyperphosphorylation. In interphase, topoisomerases could be completely linked to DNA by etoposide or camptothecin, whereas in mitosis, 50% of topoisomerase IIalpha escaped poisoning. Refractoriness to etoposide could be assigned to the salt-stable scaffold fraction of topoisomerase IIalpha, which increased from <2% in G1 phase to 48% in mitosis. Topoisomerases I and IIbeta remained completely extractable throughout the cell cycle. In summary, expression of topoisomerases increases towards mitosis, but specific activities decrease. Topoisomerase IIbeta is released from the heterochromatin, whereas topoisomerase I and IIalpha remain chromosome bound. Scaffold-associated topoisomerase IIalpha appears not to be involved in catalytic DNA turnover, though it may play a role in the replicational cycle of centriols, where it accumulates during M phase.
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Affiliation(s)
- K N Meyer
- Medizinische Poliklinik, University of Wurzburg, Germany
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14
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Warburton PE, Earnshaw WC. Untangling the role of DNA topoisomerase II in mitotic chromosome structure and function. Bioessays 1997; 19:97-9. [PMID: 9046238 DOI: 10.1002/bies.950190203] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
DNA topoisomerase II (topo II) is involved in chromosome structure and function, although its exact location and role in mitosis are somewhat controversial. This is due in part to the varied reports of its localization on mitotic chromosomes, which has been described at different times as uniformly distributed, axial on the chromosome arms and predominantly centromeric. These disparate results are probably due to several factors, including use of different preparation and fixation techniques, species differences and changes in distribution during the cell cycle. Recently, several papers have re-investigated the distribution of topo II on chromosomes as a function of cell cycle and species(1-3). The new studies suggest that Topo II has a dynamic pattern of distribution on the chromosomes, in general becoming axial as chromosomes condense during prophase and then concentrating at centromeres during metaphase. These experiments suggest a novel role for topo II in centromere structure and function.
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Affiliation(s)
- P E Warburton
- Institute of Cell and Molecular Biology, University of Edinburgh, UK
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15
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Balestrazzi A, Toscano I, Bernacchia G, Luo M, Otte S, Carbonera D. Cloning of a cDNA encoding DNA topoisomerase I in Daucus carota and expression analysis in relation to cell proliferation. Gene 1996; 183:183-90. [PMID: 8996105 DOI: 10.1016/s0378-1119(96)00557-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
DNA topoisomerase I is an enzyme involved in several processes related to DNA metabolism. Despite the physiological importance, the regulation of top1 gene expression has not yet been investigated in plants. In order to monitor the possible correlation between levels of top1 transcripts and the proliferative state of the cell, two partially overlapping cDNAs encoding DNA topoisomerase I from Daucus carota have been isolated from a poly(A)(+)-primed library, using an Arabidopsis thaliana probe, and from a cDNA library spanning the 5' region of the top1 transcript, which was constructed using an antisense specific oligonucleotide. The top1 nucleotide sequence encoded an open reading frame of 2370 bp, predicting a protein of 90 kDa. The deduced amino acid sequence showed a similarity of 51% with A. thaliana, 41% with S. cerevisiae, 40% with S. pombe and 31% with H. sapiens, respectively. Southern blot analysis, performed under moderate stringency conditions, showed the presence of a single-copy gene. Evaluation of the top1 mRNA steady-state level revealed, besides a constitutive expression in vegetative carrot tissues, an induced expression related to cell proliferation.
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Affiliation(s)
- A Balestrazzi
- Department of Genetics and Microbiology A. Buzzati-Traverso, University of Pavia, Italy
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16
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Ng CE, Bussey AM, Raaphorst GP. Sequence of treatment is important in the modification of camptothecin induced cell killing by hyperthermia. Int J Hyperthermia 1996; 12:663-78; discussion 679-80. [PMID: 8886892 DOI: 10.3109/02656739609027674] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We investigated the modification of camptothecin (CPT)-induced cell killing by hyperthermia in a radioresistant human melanoma (Sk-Mel-3) and a human normal (AG1522) cell line. CPT, a topoisomerase (topo) I inhibitor, was given as a 1 h exposure at variable doses up to 34 microM; hyperthermia was given either before or following CPT treatment. Hyperthermia was given either as a treatment of 41 degrees C for 8 h (termed lower temperature hyperthermia, LTH) or 45 degrees C for 15 min (termed higher temperature hyperthermia, HTH). LTH preceding CPT treatment had no effect on Sk-Mel-3 but potentiated killing of AG1522 cells. HTH preceding CPT treatment, however, almost completely abrogated the toxicity of CPT to both Sk-Mel-3 and AG1522 cells. These results therefore provided evidence for a lack of enhancement of CPT toxicity towards Sk-Mel-3 cells when hyperthermia preceded treatment with CPT. There was also no potentiation of killing of both cell lines when LTH followed treatment with CPT. In contrast, the killing of Sk-Mel-3 cells was slightly potentiated, whereas that of AG1522 cells was reduced, when HTH followed CPT. These results therefore suggested a potential for enhancement of killing of Sk-Mel-3 relative to AG1522 cells when HTH, but not LTH, followed CPT treatment. In addition, we found that a preceding exposure ot HTH did not affect either accumulation or efflux of[3H]CPT in both cell lines. Thus the significantly reduced cytotoxicity observed under those conditions was not related simply to a modification of accumulation or efflux of CPT. We found no significant differences in the atalytic activities of topo I extracted from the nuclei of Sk-Mel-3 and AG1522 cells that were either heated under HTH conditions or that were no subjected to such treatment. These results therefore suggested that the substantial reduction of cytotoxicity seen when HTH preceded CPT treatment was also not due to an effect on topo I catalytic activity. Our results therefore demonstrate that the sequence of application of hyperthermia and CPT is very important in determining the amount and, possibly, selective potentiation of tumour relative to normal cell cytotoxicity.
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Affiliation(s)
- C E Ng
- Ottawa Regional Cancer Centre, Canada
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17
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Matsuzaki Y, Kurokawa N, Terai S, Matsumura Y, Kobayashi N, Okita K. Cell death induced by baicalein in human hepatocellular carcinoma cell lines. Jpn J Cancer Res 1996; 87:170-7. [PMID: 8609066 PMCID: PMC5921056 DOI: 10.1111/j.1349-7006.1996.tb03155.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
We examined the action of baicalein, a flavonoid contained in the herbal medicine sho-saiko-to (TJ-9), on three cell lines of human hepatocellular carcinoma (HCC). Treatment with baicalein strongly inhibited the activity of topoisomerase II and suppressed the proliferation of all three HCC cell lines. But the mode of cell death induced by baicalein differed according to the cell line. Baicalein induced apoptosis in a concentration-dependent manner in only one cell line, and an increased concentration of baicalein produced cell death via necrosis in the other two lines. These results suggest that the inhibition of topoisomerase II is not by itself sufficient for induction of apoptosis, and that there is a more important mechanism which can account for the difference in susceptibility of cells to apoptosis induced by baicalein.
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Affiliation(s)
- Y Matsuzaki
- First Department of Internal Medicine, Yamaguchi University School of Medicine, Japan
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18
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Pantazis P. The water-insoluble camptothecin analogues: promising drugs for the effective treatment of haematological malignancies. Leuk Res 1995; 19:775-88. [PMID: 8551794 DOI: 10.1016/0145-2126(95)00048-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
After failing to exhibit benefits in clinical studies with cancer patients in the early 1970s, camptothecin (CPT) and its water-insoluble analogues are re-emerging as promising drugs with multiple actions in the treatment of human haematological malignancies. CPT analogues interfere with the mechanism of action of the nuclear enzyme topoisomerase I, while the cells progress through the S-phase of the cell cycle and this results in cell death by apoptosis. Modulations of topoisomerase I phosphorylation may indirectly modulate the cytotoxic activity of CPT analogues. In vitro, CPT analogues have exhibited increased or unaltered killing activity against leukaemia cells resistant to epipodophyllotoxins, anthracyclines, anthracenediones, and Vinca alkaloids, while development of resistance to CPT analogues renders leukaemia and lymphoma cells more sensitive to topoisomerase II-directed drugs, inducers of cell differentiation, and immunotoxins. Oral administration of the CPT analogues has circumvented the inconvenience of solubility of these drugs. Metabolic conversion of the CPT analogue 9-nitro-CPT to equally or more potent 9-amino-CPT practically makes unnecessary treatment of the patient with 9-amino-CPT, which, in addition, is costlier to prepare than 9-nitro-CPT. Considering the therapeutic, economic and handling viewpoints, the overall conclusion is that the water-insoluble CPT analogues are very promising antileukaemia/antilymphoma agents that warrant further preclinical and clinical studies.
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Affiliation(s)
- P Pantazis
- Stehlin Foundation for Cancer Research, St. Joseph Hospital, Houston, Texas, USA
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19
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Pani B, Barbisin M, Russo E, Tamaro M, Baccichetti F, Carlassare F, Marzano C, Rodighiero P, Bordin F. DNA damage and topoisomerase II inhibition induced by a benzopsoralen derivative. Mutat Res 1994; 311:277-85. [PMID: 7526193 DOI: 10.1016/0027-5107(94)90186-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The ability of 4-hydroxymethyl-4',5'-benzopsoralen (HMBP) to damage DNA of Chinese hamster ovary cells (CHO) and to inhibit the activity of topoisomerase II in vitro has been studied. This compound is characterized by a fourth ring condensed at the furan-side in the psoralen molecule. Contrary to other known furocoumarin derivatives, HMBP induces chromosomal aberrations in mammalian cells without UVA activation. The lesions induced in the dark by HMBP in DNA were studied by alkaline and neutral elution in CHO cells; comparable amounts of single-strand breaks and DNA-protein cross-links as well as the formation of double-strand breaks were detected. Moreover, HMBP appeared to inhibit the activity of mammalian topoisomerase II in vitro, in both the catenation and the decatenation assay. In these experiments the drug was effective only when it was pre-incubated with DNA substrate. These results are also consistent with the cytotoxic and mutagenic activity of HMBP in the dark, as tested on V79 Chinese hamster cells (V79/HGPRT system).
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Affiliation(s)
- B Pani
- Dipartimento di Biochimica, Biofisica e Chimica delle Macromolecole, Università di Trieste, Italy
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20
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Tsao YP, Tsao LT, Hsu SL, Chen SL. Retinoic acid represses the gene expression of topoisomerase II in HEP3B cells. Cancer Lett 1994; 87:73-7. [PMID: 7954372 DOI: 10.1016/0304-3835(94)90411-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
All-trans-retinoic acid (RA) affects cell growth and regulates gene expression. We examined the expression of topoisomerase 11 gene in Hep3B cells treated with RA. At low RA concentration which did not significantly affect the growth rate of Hep3B cells, RA inhibited the synthesis of topoisomerase II mRNA as revealed by Northern analysis and nuclear run-on analysis. These results indicated that the repression of topoisomerase II gene expression could be directly induced by RA rather than was a secondary event which occurred after cell growth was inhibited by RA. An unexpected finding is that after up to 72 h continuous exposure to RA, the topoisomerase II protein concentration remained unchanged.
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MESH Headings
- Blotting, Northern
- Carcinoma, Hepatocellular
- Cell Division/drug effects
- DNA Topoisomerases, Type II/biosynthesis
- DNA Topoisomerases, Type II/genetics
- Dose-Response Relationship, Drug
- Gene Expression Regulation, Enzymologic/drug effects
- Genes, fos/drug effects
- Genes, jun/drug effects
- Genes, p53/drug effects
- Humans
- Immunoblotting
- Liver Neoplasms
- Transcription, Genetic/drug effects
- Tretinoin/pharmacology
- Tumor Cells, Cultured
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Affiliation(s)
- Y P Tsao
- Department of Microbiology and Immunology, National Defense Medical Center, Taipei, Taiwan R.O.C
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21
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Larsen AK. Involvement of DNA topoisomerases and DNA topoisomerase inhibitors in the induction of leukemia cell differentiation. Ann Oncol 1994; 5:679-88. [PMID: 7826899 DOI: 10.1093/oxfordjournals.annonc.a058969] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Affiliation(s)
- A K Larsen
- Institut Gustave Roussy, Villejuif, France
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22
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Samuels DS, Shimizu Y, Nakabayashi T, Shimizu N. Phosphorylation of DNA topoisomerase I is increased during the response of mammalian cells to mitogenic stimuli. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1223:77-83. [PMID: 8061056 DOI: 10.1016/0167-4889(94)90075-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
DNA topoisomerase I is phosphorylated after mitogenic stimulation of 3T3-L1 mouse fibroblasts by 12-O-tetradecanoylphorbol 13-acetate (TPA), a phorbol ester tumor promoter. In vivo labeling with [32P]orthophosphate and immunoprecipitation with an anti-DNA topoisomerase I antibody has demonstrated an increase in the phosphorylation of DNA topoisomerase I in Swiss/3T3 mouse fibroblasts treated with epidermal growth factor (EGF) and H35 rat hepatoma cells treated with insulin. The only phosphorylated form of DNA topoisomerase I observed was the 100-kDa protein Digestion of DNA topoisomerase I with trypsin revealed two phosphopeptides. In addition, VT-1, a non-responsive genetic variant of 3T3-L1, and the DNA topoisomerase I inhibitor camptothecin were used to further study TPA-induced DNA topoisomerase I phosphorylation. Our results indicate that the phosphorylation of DNA topoisomerase I may be an ubiquitous response of cultured mammalian cells to mitogenic agents, even in the absence of DNA replication.
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Affiliation(s)
- D S Samuels
- Department of Molecular and Cellular Biology, University of Arizona, Tucson
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23
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Jing Y, Ohizumi H, Kawazoe N, Hashimoto S, Masuda Y, Nakajo S, Yoshida T, Kuroiwa Y, Nakaya K. Selective inhibitory effect of bufalin on growth of human tumor cells in vitro: association with the induction of apoptosis in leukemia HL-60 cells. Jpn J Cancer Res 1994; 85:645-51. [PMID: 8063619 PMCID: PMC5919529 DOI: 10.1111/j.1349-7006.1994.tb02408.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
We found that bufalin, an active principle of the Chinese medicine chan'su, has selective inhibitory effects on the growth of various human cancer cells. In order to examine whether the growth-inhibitory effect of bufalin on human cancer cells is associated with apoptosis, human leukemia cells were treated with bufalin. HL-60, ML1, and U937 leukemia cells treated with bufalin at 10(-8) M and above had condensed and fragmented nuclei. Flow cytometric analysis of these cells treated with bufalin showed fragmented DNA smaller than that of the G1 phase. DNA of HL-60 cells treated with bufalin showed a ladder pattern characteristic of apoptosis, as analyzed by agarose gel electrophoretic analysis. DNA synthesis and topoisomerase II activity of HL-60 cells were markedly inhibited as the concentration of bufalin was increased. The concentration needed for inducing apoptosis of HL-60 cells was 10(-8) M, which is comparable to that of camptothecin, but lower than those of other antitumor drugs such as cisplatin, VP16 and all-trans retinoic acid. Apoptosis was not observed when human mononuclear and polymorphonuclear cells were treated with 10(-6) M bufalin for 24 h. These results indicate the association of the growth-inhibitory effect of bufalin with the induction of apoptosis, at least in HL-60 cells, and suggest the usefulness of bufalin for differentiation-apoptosis-inducing therapy for cancer.
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MESH Headings
- Antineoplastic Agents/pharmacology
- Apoptosis/drug effects
- Bufanolides/pharmacology
- Cell Death/drug effects
- Cell Division/drug effects
- DNA, Neoplasm/analysis
- DNA, Neoplasm/biosynthesis
- Electrophoresis, Agar Gel
- HeLa Cells
- Humans
- Kinetics
- Leukemia, Myeloid/drug therapy
- Leukemia, Myeloid/metabolism
- Leukemia, Myeloid/pathology
- Leukocytes, Mononuclear/chemistry
- Leukocytes, Mononuclear/metabolism
- Materia Medica/pharmacology
- Neoplasm Proteins/biosynthesis
- Neutrophils/chemistry
- Neutrophils/metabolism
- RNA, Neoplasm/biosynthesis
- Tumor Cells, Cultured/drug effects
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Affiliation(s)
- Y Jing
- Department of Biological Chemistry, School of Pharmaceutical Sciences, Showa University, Tokyo
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24
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Hwang J, Hwong CL. Cellular regulation of mammalian DNA topoisomerases. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 1994; 29A:167-89. [PMID: 7826857 DOI: 10.1016/s1054-3589(08)60545-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- J Hwang
- Institute of Molecular Biology, Academia Sinica, Yang Ming Medical College, Taipei, Taiwan, Republic of China
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25
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Hwong C, Chen C, Shang H, Hwang J. Increased synthesis and degradation of DNA topoisomerase I during the initial phase of human T lymphocyte proliferation. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(17)46723-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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26
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Burden DA, Goldsmith LJ, Sullivan DM. Cell-cycle-dependent phosphorylation and activity of Chinese-hamster ovary topoisomerase II. Biochem J 1993; 293 ( Pt 1):297-304. [PMID: 8392338 PMCID: PMC1134354 DOI: 10.1042/bj2930297] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Cell-cycle-dependent protein levels and phosphorylation of DNA topoisomerase II in relation to its catalytic and cleavage activities were studied in Chinese-hamster ovary cells. Immunoreactive topoisomerase II protein levels were maximal in G2-phase cells, intermediate in S- and M-phase cells, and minimal in a predominantly G1-phase population. When the phosphorylation of topoisomerase II in vivo was corrected for differences in specific radioactivity of intracellular ATP, the apparent phosphorylation of S- and M-phase topoisomerase II was altered significantly. Relative phosphorylation in vivo was found to be greatest in M-phase cells and decreased in the other populations in the order: S > G2 > asynchronous. Phosphoserine was detected in every phase of the cell cycle, with a minor contribution of phosphothreonine demonstrated in M-phase cells. Topoisomerase II activity measured in vivo as 9-(4,6-O-ethylidene-beta-D-glucopyranosyl)-4'-demethylepipodophylloto xin (VP-16)-induced DNA double-strand breaks (determined by neutral filter elution) increased in the order: asynchronous < S < G2 < M. Topoisomerase II cleavage activity, assayed in vitro as the formation of covalent enzyme-DNA complexes, was lowest in S phase, intermediate in asynchronous and G2-phase cells, and maximal in M phase. Topoisomerase II decatenation activity was 1.6-1.8-fold greater in S-, G2- and M-phase populations relative to asynchronous cells. Therefore DNA topoisomerase II activity measured both in vivo and in vitro is maximal in M phase, that phase of the cell cycle with an intermediate level of immunoreactive topoisomerase II but the highest level of enzyme phosphorylation. The discordance between immunoreactive topoisomerase II protein levels, adjusted relative phosphorylation, catalytic activity, cleavage activity and amino acid residue(s) modified, suggests that the site of phosphorylation may be cell-cycle-dependent and critical in determining catalytic and cleavage activity.
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Affiliation(s)
- D A Burden
- James Graham Brown Cancer Center, Department of Medicine, University of Louisville, KY 40292
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27
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Cardenas ME, Gasser SM. Regulation of topoisomerase II by phosphorylation: a role for casein kinase II. J Cell Sci 1993; 104 ( Pt 2):219-25. [PMID: 8389373 DOI: 10.1242/jcs.104.2.219] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- M E Cardenas
- Swiss Institute for Experimental Cancer Research (ISREC), Lausanne
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28
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Tuccari G, Rizzo A, Giuffrè G, Barresi G. Immunocytochemical detection of DNA topoisomerase type II in primary breast carcinomas: correlation with clinico-pathological features. VIRCHOWS ARCHIV. A, PATHOLOGICAL ANATOMY AND HISTOPATHOLOGY 1993; 423:51-5. [PMID: 8212534 DOI: 10.1007/bf01606432] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
DNA topoisomerase type II (DT-II) is a major component of interphase nuclear matrix fractions, present in S-phase of the cell cycle. A series of 80 carcinomatous breast surgical samples was evaluated by immunohistochemistry, using a polyclonal antibody in a comparison with Ki-67 antiserum. A correlation with clinico-pathological data was also performed. Infiltrating ductal and lobular carcinomas constantly express DT-II with varying intensity of nuclear staining; a similar immunohistochemical pattern is observed with Ki-67. A frequent co-expression of DT-II and Ki-67 is encountered with double immunostaining; accordingly to these data, a linear relationship is evident when linear regression is employed. In addition, significant relationships between DT-II values and tumour size, histological grade and node involvement are shown, while an inverse correlation is appreciable between DT-II and oestrogen receptors and progesterone receptors. DT-II may be considered to be an additional operational marker for the proliferating fraction of cells in breast carcinomas.
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Affiliation(s)
- G Tuccari
- Department of Human Pathology, University of Messina, Italy
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29
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Tournier MF, Sobczak J, de Nechaud B, Duguet M. Comparison of biochemical properties of DNA-topoisomerase I from normal and regenerating liver. EUROPEAN JOURNAL OF BIOCHEMISTRY 1992; 210:359-64. [PMID: 1332866 DOI: 10.1111/j.1432-1033.1992.tb17429.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Biochemical properties of topoisomerase I from normal and regenerating rat liver were analysed using crude or fractionated nuclear extracts. We could not detect significative change in topoisomerase I content or activity (magnesium stimulation and inhibition by ATP) during the course of liver regeneration. Topoisomerase I can be resolved into two species of 97 kDa and 100 kDa, with the same pI of 8.2-8.6 as shown by two dimensional gel electrophoresis. The two polypeptides contained a non-phosphorylated precursor and others forms with variable degrees of phosphorylation. In-vitro dephosphorylation with alkaline phosphatase leads to the disappearance of the phosphorylated forms and inactivation of the enzyme. The affinity of topoisomerase I for chromatin (measured by salt elution) differs markedly between normal and regenerating liver: nearly 50% of topoisomerase I remained bound to the chromatin from normal liver at 250 mM NaCl whereas it was completely eluted from 24-h-regenerating-liver nuclei. The biological significance of these results is discussed.
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Affiliation(s)
- M F Tournier
- Laboratoire d'Enzymologie des acides nucléiques, Université Pierre et Marie Curie, Paris, France
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30
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Constantinou A, Grdina D, Kiguchi K, Huberman E. The effect of topoisomerase inhibitors on the expression of differentiation markers and cell cycle progression in human K-562 leukemia cells. Exp Cell Res 1992; 203:100-6. [PMID: 1330653 DOI: 10.1016/0014-4827(92)90044-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Treatment of human K-562-J leukemia cells for 1 h with the topoisomerase II-reactive drugs VP-16, VM-26, or mAMSA resulted in a dose-dependent inhibition of proliferation and in an increase in the percentage of cells staining positive for hemoglobin, a marker of erythroid differentiation. Staining for hemoglobin of up to about 60% of the cells was observed at 20 microM VP-16, 1 microM VM-26, and 8 microM mAMSA. Such treatment also caused a G2/M arrest in the cell cycle. Incubation of the cells with radiolabeled VP-16 indicated that the induced erythroid differentiation was not due to continuous cell exposure to a residual amount of the drug. VP-16-induced erythroid differentiation was also not affected by DNA, RNA, or protein synthesis inhibitors. Differentiation induction and the G2/M arrest evoked by VP-16, VM-26, and mAMSA were, however, reduced in the presence of novobiocin. Our results indicate that topo-reactive drugs that cause G2/M arrest in the K-562-J cell cycle can induce in these cells erythroid differentiation after a short and irreversible interaction with their target molecule(s).
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Affiliation(s)
- A Constantinou
- Biological and Medical Research Division, Argonne National Laboratory, Argonne, Illinois 60436-4833
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31
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Staron K, Kowalska-Loth B, Czerwiński RM. Effects of fluorodeoxyuridine and nalidixic acid on the activity of topoisomerase I in plasmodia of Physarum polycephalum. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1992; 24:1303-6. [PMID: 1379557 DOI: 10.1016/0020-711x(92)90205-f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
1. A regulatory coupling between the rate of cellular transcription and the activity of topoisomerase I was investigated in plasmodia of Physarum polycephalum treated with fluorodeoxyuridine or nalidixic acid. 2. Fluorodeoxyuridine at concentrations above 40 micrograms/ml lowered both the incorporation of [3H]uridine and the activity of topoisomerase I to 10% of corresponding control values. 3. Nalidixic acid, in the range of concentrations between 20-50 micrograms/ml did not inhibit the incorporation of [3H]uridine but lowered the activity of topoisomerase I by about half. 4. It is suggested that a coupling between the level of transcription and the activity of topoisomerase I in Physarum plasmodia involves only about a half of the topoisomerase I activity and is limited to transcription occurring on ribosomal genes.
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Affiliation(s)
- K Staron
- Institute of Biochemistry, Warsaw University, Poland
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32
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Bruno S, Giaretti W, Darzynkiewicz Z. Effect of camptothecin on mitogenic stimulation of human lymphocytes: involvement of DNA topoisomerase I in cell transition from G0 to G1 phase of the cell cycle and in DNA replication. J Cell Physiol 1992; 151:478-86. [PMID: 1338332 DOI: 10.1002/jcp.1041510306] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The possible involvement of DNA topoisomerase I in cell transition from G0 to G1 and in progression through the cell cycle was studied by estimating the ability of human peripheral blood lymphocytes to undergo mitogenic stimulation in the presence of the topoisomerase I inhibitor camptothecin (CAM). Exposure of quiescent G0 lymphocytes to up to 3 microM CAM for 24 h had no significant effect on their ability to subsequently undergo mitogenic stimulation in the presence of phytohemagglutinin (PHA); higher doses of CAM, although not immediately cytotoxic, impaired the mitogenic response. Stimulation of lymphocytes with PHA in the presence of < or = 1.5 microM CAM resulted in unperturbed transition of these cells from G0 to G1 characterized as an increase in cellular rRNA content, appearance of interleukin-2 receptor, and, after removal of CAM, response to interleukin-2 by entering S phase of the cell cycle. However, lymphocytes were prevented from entering S phase in the presence of CAM at a concentration of > or = 30 nM, and their rate of progression through S was minimal even at CAM concentration as low as 3 nM. When cycling lymphocytes (48 h after stimulation by PHA) were treated with CAM, the cell progression through S and G2 was also very sensitive to the inhibitor: the cells were "frozen" in S and G2 at > or = 6 nM CAM. These cells died within 24 h; their selective loss from the cultures (with only G0/G1 cells remaining) coincided with the appearance of cells with fractional DNA content, typical of apoptotic cells. Human lymphocytic leukemic MOLT-4 cells were arrested in S and G2 at > or = 7.5 nM CAM. Thus, progressions through S and G2 of both normal and leukemic lymphocytes were perturbed at approximately two orders of magnitude lower CAM concentration than the G0 to G1 transition. These data suggest that DNA replication and chromosomal events during G2 are more sensitive to inhibition of DNA topoisomerase I, compared with the early events of lymphocyte stimulation, which involve activation and transcription of numerous genes associated with the G0 to G1 transition. The antitumor properties of CAM may be related to its high cytostatic/cytotoxic activity toward cycling cells and relative resistance of cells in G0 or undergoing transition from G0 to G1.
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Affiliation(s)
- S Bruno
- Cancer Research Institute, New York Medical College, Valhalla 10595
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33
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Abstract
The DNA topoisomerase I inhibitor camptothecin (CAM) is selectively cytotoxic to S-phase cells of HL-60, and some other myelogenous leukemic lines. The early effects of cell exposure to 0.05-0.2 micrograms/ml CAM are seen after 2 h; at that time a progressive degradation of DNA in the chromatin of S-phase cells is initiated. The degradation manifests by "pulverization" of chromatin followed by coalescence of the fine granules and nuclear disintegration. Between 2 and 6 h of treatment, a loss of about 30-70% of DNA from S-phase nuclei is detected by flow cytometry. A 10-min pulse of CAM is adequate to trigger subsequent DNA degradation. Agarose gel electrophoresis of DNA from CAM-treated cells reveals a typical nucleosome core particles "ladder," suggestive of preferential degradation of spacer DNA. Despite extensive loss of DNA and nuclear disintegration, the cell membrane of CAM-treated S-phase cells remains intact for several hours, excluding trypan blue or propidium iodide. Mitochondria, assayed for their ability to maintain a transmembrane potential (rhodamine 123 retention), as well as the lysosomal proton pump (probed by supravital uptake of acridine orange) also remain unchanged in these cells. G1 cells are refractory to CAM under these conditions. Synchronization of cells in S phase by aphidicolin increases the sensitivity of the whole cell population to CAM. The data suggest that CAM or other topoisomerase I inhibitors may be effective in some myelogenous leukemias, especially in combination with treatments synchronizing cells in S phase.
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34
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Staron K, Kowalska-Loth B, Czerwinski RM, Bandorowska J, Guberska J. Topoisomerase I in actively growing plasmodia and during differentiation of the slime mold Physarum polycephalum. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1088:36-40. [PMID: 1846567 DOI: 10.1016/0167-4781(91)90150-k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A type I topoisomerase has been purified from nuclei of a slime mold Physarum polycephalum and its activity was tested during spherulation. The final preparation contained a single polypeptide of about 100 kDa. Basic properties of Physarum topoisomerase I (substrate specificity, ionic requirement, sensitivity to inhibitors) were similar to those of topoisomerases from higher eukaryotes. Specific features of Physarum enzyme were that it was rapidly inactivated at 45 degrees C and did not react with antibodies against human topoisomerase I. The activity of topoisomerase I in developed dormant spherules decreased approx. 2-fold, as compared with a 4-fold decrease of RNA and a 10-fold decrease of DNA synthesis. Basic properties of the enzyme remained unchanged during spherulation.
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Affiliation(s)
- K Staron
- Department of Biochemistry, Warsaw University, Poland
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35
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Okuda Y, Fujisawa M, Matsumoto O, Kamidono S. Testosterone dependent regulation of the enzymes involved in DNA synthesis in the rat ventral prostate. J Urol 1991; 145:188-91. [PMID: 1845773 DOI: 10.1016/s0022-5347(17)38288-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The effects of testosterone on the activities of DNA polymerase alpha, beta, and gamma as well as topoisomerase I (all enzymes involved in DNA synthesis) were examined in the rat ventral prostate. The activities of these four enzymes decreased gradually after castration in comparison with normal controls, and continued to decrease until the 14th day. Enzyme activities were almost restored to normal within 48 to 72 hr. of the commencement of daily testosterone injections (0.3 mg./0.2 ml.), and increased successively until the 14th day. The wet weight, protein content, and DNA content of the rat ventral prostate decreased after castration, while following testosterone therapy all these parameters increased to equal or exceed the control levels. These results suggested that the activities of DNA polymerase alpha, beta, and gamma and topoisomerase I are at least partially regulated by testosterone, and that these enzymes play an important role in the regulation of prostatic cellular proliferation.
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Affiliation(s)
- Y Okuda
- Department of Urology, Kobe University School of Medicine, Japan
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36
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Abstract
Studies examining the mechanisms of resistance to camptothecin and its water-soluble analogs have been reported only recently. None of these studies have involved resistance derived in vivo in humans. Some of the mechanisms already describe could be predicted from the mechanism of action of the drug and from prior studies in yeast. It is interesting that, to date, the only mechanisms of resistance relate directly to the target of the drug, DNA topoisomerase I, and that the drugs are active in cell lines exhibiting the multidrug-resistant phenotype. Should camptothecin analogs prove as active in human clinical trials as animal tests predict, it will be interesting to see if additional mechanisms of resistance emerge from studies in treated patients. On the other hand, if clinical activity is similar to that demonstrated by camptothecin 15 years ago, the issue will be of academic interest only.
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37
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Romig H, Richter A. Expression of the topoisomerase I gene in serum stimulated human fibroblasts. BIOCHIMICA ET BIOPHYSICA ACTA 1990; 1048:274-80. [PMID: 2157495 DOI: 10.1016/0167-4781(90)90067-c] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We have determined the levels of mRNA coding for human type I DNA topoisomerase (EC 5.99.1.2.) in resting and proliferating human cells in culture. After addition of serum to growth arrested cells, we observed an continuous increase in the amount of topoisomerase I mRNA, starting after serum addition and reaching a maximum at 25 h after stimulation. At the end of the S-phase, a 6-fold higher amount of topoisomerase I mRNA was present in these cells. Nuclear run on transcription experiments showed, that the increase of topoisomerase I mRNA was preceded by a 3- to 4-fold increase in de novo mRNA synthesis. In contrast, during the same time period the amount of topoisomerase I increased only by a factor of 2, and the specific activity (enzymatic activity/mg protein) remained constant.
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Affiliation(s)
- H Romig
- University of Konstanz, Department of Biology
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38
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Ghosh (Datta) R, Bhattacharjee SB. Killing and mutation induction in quiescent V79 cells as influenced by nalidixic acid. ACTA ACUST UNITED AC 1990. [DOI: 10.1016/0165-7992(90)90116-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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39
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Abstract
The induction of mammalian cell proliferation requires the expression of a specific set of genes. Tumor promoters stimulate cell growth by activating the Ca2+ and phospholipid-dependent protein kinase, protein kinase C (PKC). DNA topoisomerase I, a nuclear enzyme involved in transcription, was phosphorylated by activated PKC in vitro. Phosphorylation by PKC stimulated the DNA relaxation activity of topoisomerase I two- to three-fold. Therefore, DNA topoisomerase I is a substrate for PKC-mediated activation by phosphorylation and may serve as a nuclear target of mitogenic signals generated by tumor promoters in vivo.
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Affiliation(s)
- D S Samuels
- Department of Molecular and Cellular Biology, University of Arizona, Tucson 85721
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40
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Gene expression of human DNA polymerase alpha during cell proliferation and the cell cycle. Mol Cell Biol 1989. [PMID: 3211134 DOI: 10.1128/mcb.8.11.5016] [Citation(s) in RCA: 91] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We studied the expression of the human DNA polymerase alpha gene during cell proliferation, during cell progression through the cell cycle, and in transformed cells compared with normal cells. During the activation of quiescent cells (G0 phase) to proliferate (G1/S phases), the steady-state mRNA levels, rate of synthesis of nascent polymerase protein, and enzymatic activity in vitro exhibited a substantial and concordant increase prior to the peak of in vivo DNA synthesis. In transformed cells, the respective values were amplified greater than 10-fold. In actively growing cells separated into discrete stages of the cell cycle by counterflow elutriation or by mitotic shakeoff, levels of steady-state transcripts, translation rates, and enzymatic activities of polymerase alpha were constitutively and concordantly expressed at all stages of the cell cycle, with only a moderate elevation prior to the S phase and a slight decline in the G2 phase. These findings support the conclusion that the regulation of human DNA polymerase alpha gene expression is at the transcriptional level and strongly suggest that the regulatory mechanisms that are operative during the entrance of a cell into the mitotic cycle are fundamentally different from those that modulate polymerase alpha expression in continuously cycling cells.
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41
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Fujisawa M, Yoshida S, Kojima K, Kamidono S. Biochemical changes in testicular varicocele. ARCHIVES OF ANDROLOGY 1989; 22:149-59. [PMID: 2665680 DOI: 10.3109/01485018908986765] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The precise mechanism of the hypospermatogenesis associated with varicocele has remained uncertain, although there have been a number of speculations on the etiology of the associated infertility. The altered spermatogenesis has been attributed to the reflux of toxic metabolites from either adrenal or renal origin, disturbed hormone status, spermatic venous hypertension, testicular hypoxia secondary to stasis, and abnormal temperature regulation. However, the biochemical changes of the testicular tissue with varicocele have been only partially explored. This overview includes the available information on the biochemical change in the testes associated with varicocele as well as the introduction of basic biochemical aspects on the testes, which may give new insights into the possible pathophysiological mechanism of male infertility.
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Affiliation(s)
- M Fujisawa
- Department of Urology, Kobe University School of Medicine, Japan
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42
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Wahl AF, Geis AM, Spain BH, Wong SW, Korn D, Wang TS. Gene expression of human DNA polymerase alpha during cell proliferation and the cell cycle. Mol Cell Biol 1988; 8:5016-25. [PMID: 3211134 PMCID: PMC365595 DOI: 10.1128/mcb.8.11.5016-5025.1988] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
We studied the expression of the human DNA polymerase alpha gene during cell proliferation, during cell progression through the cell cycle, and in transformed cells compared with normal cells. During the activation of quiescent cells (G0 phase) to proliferate (G1/S phases), the steady-state mRNA levels, rate of synthesis of nascent polymerase protein, and enzymatic activity in vitro exhibited a substantial and concordant increase prior to the peak of in vivo DNA synthesis. In transformed cells, the respective values were amplified greater than 10-fold. In actively growing cells separated into discrete stages of the cell cycle by counterflow elutriation or by mitotic shakeoff, levels of steady-state transcripts, translation rates, and enzymatic activities of polymerase alpha were constitutively and concordantly expressed at all stages of the cell cycle, with only a moderate elevation prior to the S phase and a slight decline in the G2 phase. These findings support the conclusion that the regulation of human DNA polymerase alpha gene expression is at the transcriptional level and strongly suggest that the regulatory mechanisms that are operative during the entrance of a cell into the mitotic cycle are fundamentally different from those that modulate polymerase alpha expression in continuously cycling cells.
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Affiliation(s)
- A F Wahl
- Department of Pathology, Medical School, Stanford University, California 94305
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43
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Ackerman P, Glover CV, Osheroff N. Phosphorylation of DNA topoisomerase II in vivo and in total homogenates of Drosophila Kc cells. The role of casein kinase II. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)37803-7] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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44
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Abstract
Sc1-70, an autoantigen in systemic sclerosis, may accelerate collagen gene transcription by virtue of its activity as a topoisomerase I (topo I), a DNA template-modifying enzyme. A survey of sequences corresponding to all or part of the known topo I binding sequence AGAACTTAGAGAAAATTTAAA in four fibrillar collagen genes (three of them dermal) and sixteen non-collagen genes showed a striking preponderance of the tetramer 5'-CTTA-3', comprising the core of this binding sequence, at the exon-intron junctions of the fibrillar collagen genes (59% compared with 16% in the control group). In addition, a non-random clustering of three potential topo I binding sites was seen within 350 base-pairs of 5' flanking DNA in the dermal collagen gene alpha 2(I), and a fourth site occurred in the promoter region of the alpha 1(III) gene. The findings suggest that a selective vulnerability to the action of Sc1-70/topo I is built into the structure of the dermal collagen genes.
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Affiliation(s)
- A Douvas
- Clinical Immunology and Rheumatic Disease Section, University of Southern California, Los Angeles 90033
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45
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46
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Schneider E, Darkin SJ, Robbie MA, Wilson WR, Ralph RK. Mechanism of resistance of non-cycling mammalian cells to 4'-[9-acridinylamino]methanesulphon-m-anisidide: role of DNA topoisomerase II in log- and plateau-phase CHO cells. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 949:264-72. [PMID: 2831986 DOI: 10.1016/0167-4781(88)90151-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
CHO-AA8 cells were used as a model system to study the role of DNA topoisomerase II in the resistance of non-cycling cells to amsacrine. Plateau-phase AA8 cells have previously been shown to be resistant to amsacrine and to contain fewer DNA breaks than log-phase cells after drug treatment (Robbie, M.A., Baguley, B.C., Denny, W.A., Gavin, J.R. and Wilson, W.R. (1988) Cancer Res., in press). The phage P4-unknotting activity of nuclear extracts decreased 2-fold when AA8 cells entered into the non-cycling state, but there was no difference in sensitivity to amsacrine between log- and plateau-phase nuclear extracts. Drug stimulation of protein-DNA complex formation was similar in whole cells, isolated nuclei and nuclear extracts from either log- or plateau-phase cells. However, stimulation of complex formation in cells, nuclei or nuclear extracts was approx. 4-fold lower in plateau-phase than in log-phase. The data presented suggested that drug-enzyme interaction was altered in plateau-phase cells.
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Affiliation(s)
- E Schneider
- Department of Cellular and Molecular Biology, University of Auckland, New Zealand
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47
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Leduc Y, Lawrence JJ, De Murcia G, Poirier GG. Cell cycle regulation of poly(ADP-ribose) synthetase in FR3T3 cells. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 968:275-82. [PMID: 3125857 DOI: 10.1016/0167-4889(88)90018-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The properties of poly(ADP-ribose) synthetase were studied throughout the cell cycle progression of non-synchronized rat FR3T3 fibroblasts using an immunological and biochemical approach. Cells in the various phases of the cell cycle were sorted from an asynchronously growing population by using flow cytofluorometry. G1, S and G2 + M fractions were used for enzymatic assays in the presence of saturating concentrations of DNAase I for the analysis of total poly(ADP-ribose) synthetase; maximal enzyme activity was found in the G2 + M phase. Purified IgG, specific for the FR3T3 poly(ADP-ribose) synthetase were used for the labelling of endogenous synthetase in order to quantify the enzyme immunologically. Localization of nuclear immunofluorescence was observed and analysis of poly(ADP-ribose) synthetase content throughout the cell cycle were carried out using double fluorescent staining and cytofluorometry. Poly(ADP-ribose) synthetase content as measured immunologically was found to increase from G1 to S and G2 + M phases. Quiescent cells showed a lower content as measured immunologically of poly(ADP-ribose) synthetase than cells in the G1 phase. In exponentially growing cells, the ratio between enzyme activity of poly(ADP-ribose) synthetase over the amount of enzyme measured immunologically was found to be higher in the G2 + M phase. These results show that a cell-cycle specific event activates poly(ADP-ribose) synthetase in the G2 + M phase.
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Affiliation(s)
- Y Leduc
- Centre de recherche sur les mécanismes de sécrétion, Faculté des Sciences, Université de Sherbrooke, Québec, Canada
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48
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Crespi MD, Mladovan AG, Baldi A. Increment of DNA topoisomerases in chemically and virally transformed cells. Exp Cell Res 1988; 175:206-15. [PMID: 2831071 DOI: 10.1016/0014-4827(88)90267-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The activities of topoisomerases I and II were assayed in subcellular extracts obtained from nontumorigenic BALB/c 3T3 A31 and normal rat kidney (NRK) cell lines and from the same cells transformed by benzo[a]pyrene (BP-A31), Moloney (M-MSV-A31) and Kirsten (K-A31) sarcoma viruses, and simian virus 40 (SV-NRK). The enzymatic activity of topoisomerase I was monitored by the relaxation of negatively supercoiled pBR322 DNA and by the formation of covalent complexes between 32P-labeled DNA and topoisomerase I. Topoisomerase II activity was determined by decatenation of kinetoplast DNA (k-DNA). It was found that nuclear and cytoplasmic type I topoisomerase specific activities were higher in every transformed cell line than in the normal counterparts. These differences cannot be attributed to an inhibitory factor present in A31 cells. When chromatin was treated at increasing ionic strengths, the 0.4 M NaCl extract showed the highest topoisomerase I specific activity. Moreover, in this fraction the transformed cells exhibited the most significant increment in the enzymatic activity as compared with nontransformed cultures. Spontaneously transformed A31 cells showed topoisomerase I activity similar to that of extracts of cells transformed by benzo[a]pyrene. Topoisomerase II specific activity was also increased in SV-NRK cells, as judged by the assay for decatenation of k-DNA to yield minicircle DNA.
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Affiliation(s)
- M D Crespi
- Instituto de Biología y Medicina Experimental, Buenos Aires, Argentina
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49
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Fujisawa M, Yoshida S, Matsumoto O, Kojima K, Kamidono S. Decrease of topoisomerase I activity in the testes of infertile men with varicocele. ARCHIVES OF ANDROLOGY 1988; 21:45-50. [PMID: 2847665 DOI: 10.3109/01485018808986732] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Topoisomerase I, which is involved in DNA metabolism, was measured in the testes of 37 infertile men with varicocele, using a minute amount of testicular biopsy specimen. In 38% of infertile men topoisomerase I activity was lower than that of normal men. Forty-six percent of patients with high grade varicocele (grade III) showed reduced topoisomerase I activity, while only 26% of patients with low grade varicocele (grades I and II) showed reduced levels of topoisomerase I. Johnsen's score of the patients with low topoisomerase I activity was lower than that of patients with normal levels of topoisomerase I. The decrease of topoisomerase I activity may be correlated with at least some fraction of hypospermatogenesis associated with varicocele.
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Affiliation(s)
- M Fujisawa
- Department of Urology, Kobe University School of Medicine, Japan
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50
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Kaplan JG, Brown DL, Chaly N, Greer WL, Prasad KV, Severini A, Sahai BM. Structural and evolutionary implications of the packaging of DNA for differentiation and proliferation in the lymphocyte. J Mol Evol 1987; 26:173-9. [PMID: 2834558 DOI: 10.1007/bf02099849] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
During the differentiation of the clonally distributed lymphocytes of mouse and man into mature resting B and T cells, their DNA becomes tightly packed into dense heterochromatin masses and exhibits very little transcriptional activity; it also becomes extensively nicked, containing some 3000-4000 single-strand breaks per diploid genome. The nuclear matrix is sparse and poorly organized and there are but trace amounts of the matrix-linked enzyme DNA topoisomerase II; the nucleus of these small cells is surrounded by a thin rim of cytoplasm. The resting cell can thus be considered (by analogy to a sperm cell) as a vector for transporting tightly packed and relatively inert genetic information to all parts of the body. When the lymphocyte is stimulated to enter a proliferative cycle by binding of appropriately presented antigen or mitogen to relevant membrane receptors, the cell enlarges, due to increased synthesis of protein; the dense heterochromatin is pulled out into very small clumps, as a result of an enormous growth in size as well as complexity of the nuclear matrix, and a great increase in transcriptional activity occurs. We have identified four nuclear matrix antigens that are very widely conserved in the evolution of eucaryotes and that occupy distinctive domains in interphase nuclei. Of particular interest is antigen P1, detected in organisms ranging from algae to mammals. By virtue of its location at the interface between nuclear envelope and chromatin, we propose that it plays a major and evolutionarily conserved role in chromatin organization and orientation in all eucaryotic cell types.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J G Kaplan
- Department of Biochemistry, University of Alberta, Edmonton, Canada
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