Michael Mattern

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Results of filter elution assays of lesions produced in the DNA of cultured L1210 cells by the antineoplastic alkaloid camptothecin support the notion that topoisomerase I is an intracellular target of this drug. One to 10 microM camptothecin induced DNA single-strand, but not double-strand, breaks when incubated with intact cells or with their isolated(More)
Marine natural products provide a rich source of chemical diversity that can be used to design and develop new, potentially useful therapeutic agents. We report here that scytonemin, a pigment isolated from cyanobacteria, is the first described small molecule inhibitor of human polo-like kinase, a serine/threonine kinase that plays an integral role in(More)
Resistance to chemotherapy targeting microtubules could be partially because of the delay in chromosome condensation and segregation during mitosis. The Chfr pathway has been defined recently, and its activation causes a delay in chromosome condensation in response to mitotic stress. Because Chfr contains a RING-finger domain, we tested whether Chfr(More)
The free radical scavengers, dimethyl sulfoxide (Me2SO) and thiourea, were used to assess the role of free radicals in the production of intercalator-induced DNA breaks and cytotoxicity in mouse leukemia L1210 cells. Both agents decreased X-ray break production, and this decrease was comparable in magnitude to the degree of inhibition of X-ray-induced cell(More)
Merbarone has previously been shown to have antitumor activity of unknown mechanism in P38S and 1,1210 tumor models (A. D. Brewer et a/., Biochem. Pharmacol., 34:2047-2050,1985) and is currently undergo ing Phase I clinical trials. Here we report that merbarone is an inhibitor of topoisomerase II. Merbarone inhibited purified mammalian topoisom-erase II(More)
  • Xun Zuo, Shuisen Li, +6 authors Tauseef R Butt
  • 2005
Severe acute respiratory syndrome coronavirus (SARS-CoV) membrane protein and 5-lipoxygenase-activating protein (FLAP) are among a large number of membrane proteins that are poorly expressed when traditional expression systems and methods are employed. Therefore to efficiently express difficult membrane proteins, molecular biologists will have to develop(More)
The activity of topoisomerase II and the cellular content of the 170kD and 180kD forms of the enzyme were studied as functions of transformation and growth state by using normal and ras-transformed NIH-3T3 cells. Total topoisomerase II activity, as measured by the unknotting of P4 DNA, was higher in ras-transformed than in normal cells in similar growth(More)
DMA intercalating drugs and the epipodophyllotoxins etopo-side and teniposide interfere with the action of mammalian DNA topoisomerase II by trapping an intermediate complex of the enzyme covalently linked to the 5'-termini of DNA breaks. This effect can be observed in intact cells by alkaline elution mea surement of protein-associated DNA strand breaks. To(More)
The ubiquitin pathway regulates diverse functions including protein localization and stability. The complexity of the pathway involving nearly 40 identified E2 conjugating enzymes and over 600 E3 ligases raises the issue of specificity. With the E2s and E3s fitting into a limited number of classes based on bioinformatics, structures, and proven activities,(More)
A combination of tumor necrosis factor (INI) and the topoisomerase I inhibitor, camptothecin, or the topoisomerase II inhibitors, teniposide and amsacrine, produced dose-dependent synergistic cytotoxicity against the murine L929 fibrosarcoma cells. Similar synergy was not observed with a combination of TNF and bleomycin. To define the role of TNF in the(More)