title: DNA crosslinking and biological activity of a hairpin polyamide-chlorambucil conjugate.
abstract: A prototype of a novel class of DNA alkylating agents, which combines the DNA crosslinking moiety chlorambucil (Chl) with a sequence-selective hairpin pyrrole-imidazole polyamide ImPy-beta-ImPy-gamma-ImPy-beta-Dp (polyamide 1), was evaluated for its ability to damage DNA and induce biological responses. Polyamide 1-Chl conjugate (1-Chl) alkylates and interstrand crosslinks DNA in cell-free systems. The alkylation occurs predominantly at 5'-AGCTGCA-3' sequence, which represents the polyamide binding site. Conjugate-induced lesions were first detected on DNA treated for 1 h with 0.1 micro M 1-Chl, indicating that the conjugate is at least 100-fold more potent than Chl. Prolonged incubation allowed for DNA damage detection even at 0.01 micro M concentration. Treatment with 1-Chl decreased DNA template activity in simian virus 40 (SV40) in vitro replication assays. 1-Chl inhibited mammalian cell growth, genomic DNA replication and cell cycle progression, and arrested cells in the G2/M phase. Moreover, cellular effects were observed at 1-Chl concentrations similar to those needed for DNA damage in cell-free systems. Neither of the parent compounds, unconjugated Chl or polyamide 1, demonstrated any cellular activity in the same concentration range. The conjugate molecule 1-Chl possesses the sequence-selectivity of a polyamide and the enhanced DNA reactivity of Chl.
authors.affiliation: Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, NY 14263, USA.
authors.forename: Yong-Dong
authors.initials: YD
authors.lastname: Wang
authors.forename: Jaroslaw
authors.initials: J
authors.lastname: Dziegielewski
authors.forename: Nicholas R
authors.initials: NR
authors.lastname: Wurtz
authors.forename: Barbara
authors.initials: B
authors.lastname: Dziegielewska
authors.forename: Peter B
authors.initials: PB
authors.lastname: Dervan
authors.forename: Terry A
authors.initials: TA
authors.lastname: Beerman
mesh_terms: D000478:Alkylation; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002699:Chlorambucil / Q000737:chemistry* / Q000494:pharmacology; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004247:DNA / Q000096:biosynthesis / Q000737:chemistry* / Q000187:drug effects; D004261:DNA Replication / Q000187:drug effects; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D019169:Jurkat Cells; D015394:Molecular Structure; D009757:Nylons / Q000737:chemistry* / Q000494:pharmacology; D014176:Protein Biosynthesis; D011506:Proteins / Q000187:drug effects; D012313:RNA / Q000096:biosynthesis / Q000187:drug effects; D013539:Simian virus 40 / Q000235:genetics; D014407:Tumor Cells, Cultured
chemical_list: D003432:Cross-Linking Reagents; D004279:DNA, Viral; D009757:Nylons; D011506:Proteins; D002699:Chlorambucil; D012313:RNA; D004247:DNA