title: Modulation of DNA topoisomerase II activity and expression in melanoma cells with acquired drug resistance.
abstract: The role of DNA topoisomerases (Topo) IIalpha and IIbeta was investigated in various drug-resistant melanoma cells. Melanoma cells resistant to etoposide, exhibited an up to tenfold reduced Topo II activity corresponding to an increasing degree of drug resistance indicating that modulation of Topo II activity contribute to the drug-resistant phenotype. The reduction of Topo II activity was reflected by decreased nuclear amounts of both Topo II isoforms.
authors.affiliation: Institute of Pathology, Charité, Humboldt University Berlin, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Lage
authors.forename: H
authors.initials: H
authors.lastname: Helmbach
authors.forename: M
authors.initials: M
authors.lastname: Dietel
authors.forename: D
authors.initials: D
authors.lastname: Schadendorf
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D001483:Base Sequence; D017931:DNA Primers; D004250:DNA Topoisomerases, Type II / Q000096:biosynthesis* / Q000378:metabolism; D019008:Drug Resistance, Neoplasm; D005047:Etoposide / Q000494:pharmacology; D006801:Humans; D008545:Melanoma / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D008969:Molecular Sequence Data; D020033:Protein Isoforms; D014407:Tumor Cells, Cultured
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D017931:DNA Primers; D020033:Protein Isoforms; D005047:Etoposide; D004250:DNA Topoisomerases, Type II