title: Synthesis, biophysical characterization, and anti-HIV activity of glyco-conjugated G-quadruplex-forming oligonucleotides.
abstract: Novel hybrid oligonucleotides carrying the G-quadruplex-forming d(5'TGGGAG3') sequence, conjugated with mono- or disaccharides at the 3' or 5'-end through phosphodiester bonds, have been synthesized as potential anti-HIV agents, via a fully automated, online phosphoramidite-based solid-phase strategy. CD-monitored thermal denaturation studies on the resulting quadruplexes indicated the insertion of a single monosaccharide at the 3'-end as the optimal modification, conferring improved stability to the quadruplex complex. In addition, the 3'-conjugation with glucose or mannose converted the anti-HIV inactive unmodified oligomer into active compounds. On the contrary, the 5'-tethering with these monosaccharides, as well as the conjugation, either at the 5' or 3'-end, with sucrose, were in all cases detrimental to quadruplex stability and did not improve the biological activity. On the basis of the assumption that the kinetically and thermodynamically favored formation of the quadruplex complex is a prerequisite for efficient antiviral activity, a novel bis-conjugated oligonucleotide was designed. This combined a mannose residue at the 3'-phosphate end with bulky aromatic tert-butyldiphenylsilyl (TBDPS) group at the 5'-end, previously shown to markedly favor the formation of quadruplex complexes. The 5',3'-bis-conjugated 6-mer, for which a detailed biophysical characterization has been carried out, resulted in 3-fold greater antiviral activity against HIV-1 than the sole 3'-glyco-conjugated oligonucleotide.
authors.affiliation: Dipartimento di Chimica Organica e Biochimica and Dipartimento di Chimica Paolo Corradini, Università degli Studi di Napoli Federico II, Via Cintia 4, I-80126 Napoli, Italy.
authors.forename: Jennifer
authors.initials: J
authors.lastname: D'Onofrio
authors.forename: Luigi
authors.initials: L
authors.lastname: Petraccone
authors.forename: Luigi
authors.initials: L
authors.lastname: Martino
authors.forename: Giovanni
authors.initials: G
authors.lastname: Di Fabio
authors.forename: Alfonso
authors.initials: A
authors.lastname: Iadonisi
authors.forename: Jan
authors.initials: J
authors.lastname: Balzarini
authors.forename: Concetta
authors.initials: C
authors.lastname: Giancola
authors.forename: Daniela
authors.initials: D
authors.lastname: Montesarchio
mesh_terms: D019380:Anti-HIV Agents / Q000138:chemical synthesis* / Q000494:pharmacology*; D002460:Cell Line; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D006160:Guanosine Triphosphate / Q000737:chemistry; D015497:HIV-1 / Q000187:drug effects; D015498:HIV-2 / Q000187:drug effects; D006801:Humans; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008358:Mannose / Q000737:chemistry*; D009691:Nucleic Acid Denaturation; D009841:Oligonucleotides / Q000138:chemical synthesis* / Q000494:pharmacology*; D013395:Sucrose / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D019380:Anti-HIV Agents; D009841:Oligonucleotides; D013395:Sucrose; D006160:Guanosine Triphosphate; D008358:Mannose