Studies were conducted to determine the possible involvement of DNA topoisomerase II (Topo II) in the induction of differentiation in two human promyeloc)tic 111 (ill leukemia cell variants that are either sus ceptible or resistant to differentiation induced by phorbol-12-myristate13-acetate (I'M \). a protein kinase C activator. The acquisition of maturation markers and changes in the activity...

Class III β-tubulin (TUBB3) and Topoisomerase-II (topo-II) are considered to be the predictors of therapeutic efficacy and outcome in several types of human neoplasm. However, whether TUBB3 or topo-II may predict the response to combination chemotherapy and prognosis in patients with advanced thymic carcinoma (ATC) remains unclear. The aim of the present study was to investigate the prognostic ...

Topoisomerase II (topo II) is a ubiquitous enzyme that is essential for cell survival through its role in regulating DNA topology and chromatid separation. Topo II can be poisoned by common chemotherapeutics (such as doxorubicin and etoposide), leading to the accumulation of cytotoxic enzyme-linked DNA doublestranded breaks. In contrast, nonbreak-inducing topo II catalytic inhibitors have also ...

Ataxia telangiectasia (AT) cell lines are characterised by their hypersensitivity to ionizing radiation and bleomycin, and their failure to inhibit DNA synthesis after DNA damage. A recent report [Singh et al. (1988) Nucl. Acids Res. 16, 3919-3929] indicated that a reduction in topoisomerase II (topo II) activity was a feature of AT lymphoblast cell lines. We have studied the possible role of D...

INTRODUCTION Sumoylation is involved in nucleolus-nucleoplasm transport of DNA topoisomerase I (topo I), which may associate with changes of cellular and topo I functions. Skin fibroblasts of patients with systemic sclerosis (SSc) exhibit profibrotic cellular changes. The aims of this study were to examine the catalytic function and sumoylation of topo I in the nuclei of SSc fibroblasts, a majo...

We have demonstrated that, in Escherichia coli, quinolone antimicrobial agents target topoisomerase IV (topo IV). The inhibition of topo IV becomes apparent only when gyrase is mutated to quinolone resistance. In such mutants, these antibiotics caused accumulation of replication catenanes, which is diagnostic of a loss of topo IV activity. Mutant forms of topo IV provided an additional 10-fold ...

DNA topoisomerase I (Topo I) specifically phosphorylates arginineserine-rich (SR proteins) splicing factors and is potentially involved in pre-mRNA-splicing regulation. Using a Topo I-deficient murine B lymphoma-derived subclone (P388-45/C) selected for its resistance to high dosage of the antitumor drug camptothecin, we show that Topo I depletion results in the hypophosphorylation of SR protei...

DNA topoisomerase II (topo II) is involved in unlinking replicating DNA and organizing mitotic chromosomes. Topo II is the target of many antitumour drugs. Topo II inhibition results in extensive catenation of newly replicated DNA and may potentially perturb chromatin assembly. Here, we show that the topo II inhibitor ICRF-193 does not prevent the bulk of nucleosome deposition, but perturbs nuc...

DNA topoisomerases (topo) are the cellular targets of several anticancer drugs used today in the clinic. Our previous work demonstrated that certain tyrphostin derivatives, known as protein tyrosine kinase antagonists, are catalytic inhibitors of DNA topoisomerases I (topo I) in vitro. In this study, we examined the ability of tyrphostin derivatives to affect the activity of topo I in the cell ...

A number of established and investigational anticancer drugs slow the religation step of DNA topoisomerase I (topo I). These agents induce cytotoxicity by stabilizing topo I-DNA covalent complexes, which in turn interact with advancing replication forks or transcription complexes to generate lethal lesions. Despite the importance of topo I-DNA covalent complexes, it has been difficult to detect...