title: BRACO19 analog dimers with improved inhibition of telomerase and hPot 1.
abstract: Human chromosomes terminate with telomeres, which contain double-stranded G-rich, repetitive DNA followed by a single-stranded overhang of the G-rich sequence. Single-stranded oligonucleotides containing G-rich telomeric repeats have been observed in vitro to fold into a variety of G-quadruplex topologies depending on the solution conditions. G-quadruplex structures are notable in part because G-quadruplex ligands inhibit both the enzyme telomerase and other telomere-binding proteins. Because telomerase is required for growth by the majority of cancers, G-quadruplex-stabilizing ligands have become an attractive platform for anticancer drug discovery. Here, we present the preparation and biochemical activities of a novel series of 3,6-disubstituted acridine dimers modeled after the known G-quadruplex ligand BRACO19. These BRACO19 Analog Dimer (BAD) ligands were shown to bind to human telomeric DNA and promote the formation of intramolecular G-quadruplexes in the absence of monovalent cations. As expected, the BAD ligands bound to telomeric DNA with a 1:1 stoichiometry, whereas the parent compound BRACO19, a monomer, bound with a 2:1 stoichiometry. The BAD ligands exhibited potent inhibition of human telomerase with IC(50) values similar to or lower than those of BRACO19. Furthermore, the BAD ligands displayed greater potency in the inhibition of hPot1 and increased selectivity for G-quadruplex DNA when compared to BRACO19. Collectively, these experiments support the hypothesis that there is an increased potency and selectivity to be gained in the design of G-quadruplex-stabilizing agents that incorporate multiple interactions.
authors.affiliation: Division of Medicinal Chemistry and Natural Products, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7360, USA.
authors.forename: Yuan-Te
authors.initials: YT
authors.lastname: Fu
authors.forename: Brian R
authors.initials: BR
authors.lastname: Keppler
authors.forename: Joana
authors.initials: J
authors.lastname: Soares
authors.forename: Michael B
authors.initials: MB
authors.lastname: Jarstfer
mesh_terms: D000166:Acridines / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D002942:Circular Dichroism; D019281:Dimerization; D054856:G-Quadruplexes; D006801:Humans; D020128:Inhibitory Concentration 50; D000089804:Shelterin Complex; D019098:Telomerase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D016615:Telomere / Q000737:chemistry; D034501:Telomere-Binding Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D000166:Acridines; C540822:BAD1 compound; C540821:BAD2 compound; C540820:BAD3 compound; C440849:POT1 protein, human; D000089804:Shelterin Complex; D034501:Telomere-Binding Proteins; D019098:Telomerase; C454064:BRACO-19