title: Distamycin A, a minor groove binder, changes enediyne-induced DNA cleavage sites and enhances apoptosis.
abstract: We examined the effects of a minor groove binder, distamycin A, on DNA cleavage and apoptosis induced by an enediyne antitumor antibiotic, C1027, using 32P-labeled DNA fragments obtained from human genes. C1027 alone induced DNA cleavage particularly at the 5'-TTTT-3'/3'-AAAA-5' sequence (cutting sites are underlined). The addition of distamycin A enhanced the double-strand DNA cleavage at the 5'-CCT-3'/3'-GGA-5' and 5'-CCA-3'/3'-GGT-5' sequences, with a two-nucleotide 3'-stagger of the cleaved residues. These results suggest that distamycin A forms a heterodimer with C1027 to bind to DNA at GC-rich regions, resulting in amplification of DNA cleavage at these regions. Distamycin A enhanced C1027-induced DNA ladder formation and cytotoxicity in HL-60 cells. Therefore, amplification of DNA cleavage at GC-rich regions may result in enhancement of apoptosis. The present study on amplifiers of antitumor agents showed a novel approach to the potentially effective antitumor therapy.
authors.affiliation: Department of Environmental and Molecular Medicine, Mie University School of Medicine, Tsu, Mie, 514-8507, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Hiraku
authors.forename: Shinji
authors.initials: S
authors.lastname: Oikawa
authors.forename: Shosuke
authors.initials: S
authors.lastname: Kawanishi
mesh_terms: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001483:Base Sequence; D001665:Binding Sites; D004247:DNA / Q000378:metabolism*; D004214:Distamycins / Q000378:metabolism / Q000494:pharmacology*; D053281:Enediynes; D008969:Molecular Sequence Data
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D004214:Distamycins; D053281:Enediynes; C058024:C 1027; C030000:stallimycin; D004247:DNA