title: Bizelesin, a bifunctional cyclopropylpyrroloindole alkylating agent, inhibits simian virus 40 replication in trans by induction of an inhibitor.
abstract: Bizelesin, a bifunctional DNA minor groove alkylating agent, inhibits both cellular and viral (SV40) DNA replication in whole cells. Bizelesin inhibition of SV40 DNA replication was analyzed in SV40-infected cells, using two-dimensional (2D) neutral agarose gel electrophoresis, and in a cell-free SV40 DNA replication assay. Within 1 h of bizelesin addition to infected cells, a similar rapid decrease in both the level of SV40 replication intermediates and replication activity was observed, indicating inhibition of initiation of SV40 DNA replication. However, prolonged bizelesin treatment (>/=2 h) was associated with a reduced extent of elongation of SV40 replicons, as well as the appearance on 2D gels of intense spots, suggestive of replication pause sites. Inhibition of elongation and induction of replication pause sites may result from the formation of bizelesin covalent bonds on replicating SV40 molecules. The level of in vitro replication of SV40 DNA also was reduced when extracts from bizelesin-treated HeLa cells were used. This effect was not dependent upon the formation of bizelesin covalent bonds with the template DNA. Mixing experiments, using extracts from control and bizelesin-treated cells, indicated that reduced DNA replication competence was due to the presence of a trans-acting DNA replication inhibitor, rather than to decreased levels or inactivation of essential replication factor(s).
authors.affiliation: Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, New York 14263, USA.
authors.forename: M M
authors.initials: MM
authors.lastname: McHugh
authors.forename: S R
authors.initials: SR
authors.lastname: Kuo
authors.forename: M H
authors.initials: MH
authors.lastname: Walsh-O'Beirne
authors.forename: J S
authors.initials: JS
authors.lastname: Liu
authors.forename: T
authors.initials: T
authors.lastname: Melendy
authors.forename: T A
authors.initials: TA
authors.lastname: Beerman
mesh_terms: D000477:Alkylating Agents / Q000494:pharmacology*; D000818:Animals; D000998:Antiviral Agents / Q000096:biosynthesis* / Q000494:pharmacology* / Q000502:physiology; D002460:Cell Line; D002474:Cell-Free System; D002522:Chlorocebus aethiops; D018736:DNA Adducts / Q000096:biosynthesis; D004249:DNA Damage; D004261:DNA Replication / Q000187:drug effects; D004279:DNA, Viral / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000302:isolation & purification; D004305:Dose-Response Relationship, Drug; D000080890:Duocarmycins; D015180:Electrophoresis, Gel, Two-Dimensional; D006367:HeLa Cells; D006358:Hot Temperature; D006801:Humans; D007211:Indoles / Q000494:pharmacology*; D013539:Simian virus 40 / Q000737:chemistry / Q000187:drug effects* / Q000235:genetics; D015534:Trans-Activators / Q000096:biosynthesis; D014508:Urea / Q000031:analogs & derivatives* / Q000494:pharmacology; D014779:Virus Replication / Q000187:drug effects* / Q000235:genetics
chemical_list: D000477:Alkylating Agents; D000998:Antiviral Agents; D018736:DNA Adducts; D004279:DNA, Viral; D000080890:Duocarmycins; D007211:Indoles; D015534:Trans-Activators; D014508:Urea; C072257:bizelesin