Synthesis and Evaluation of a Triplex-Forming Oligonucleotide-Pyrrolobenzodiazepine Conjugate

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• 作者：Zhanna V. Zhilina ; Amy J. Ziemba ; John O. Trent ; Michael W. Reed ; Vladimir Gorn ; Qun Zhou ; Wenhu Duan ; Laurence Hurley ; and Scot W. Ebbinghaus
• 刊名：Bioconjugate Chemistry
• 出版年：2004
• 出版时间：November 2004
• 年：2004
• 卷：15
• 期：6
• 页码：1182 - 1192
• 全文大小：440K
• 年卷期：v.15,no.6(November 2004)
• ISSN：1520-4812

文摘

In most cases, unmodified oligonucleotides designed as antigene molecules are incapable of bindingto DNA with sufficient stability to prevent gene expression. To stabilize binding to a polypurine tractin the HER-2/neu promoter, a triplex forming oligonucleotide (TFO) was conjugated to a pyrrolo[1,4]benzodiazepine (PBD), desmethyltomaymycin, and site-specific DNA binding was evaluated. Anactivated ester of the PBD moiety was conjugated by an acylation reaction to a free primary amine ona 50-atom aliphatic linker at the 5' end of the TFO. This long aliphatic linker was designed to providea bridge from the major groove binding site of the TFO to the minor groove binding site of the PBD.Triplex formation by the resulting TFO-PBD conjugate occurred more slowly and with a nearly 30-fold lower affinity compared to an unconjugated TFO. PBD binding to the triplex target wasdemonstrated by protection from restriction enzyme digestion, and covalent binding to the exocyclicamino group of guanine was inferred by substituting specific guanines with inosines. Although thebinding of the TFO was less efficient, this report demonstrates that in principle, TFOs can be used todirect the binding of a PBD to specific location. Further optimization of TFO-PBD conjugate design,likely involving optimization of the linker and perhaps placing a PBD at both ends of the TFO, willbe needed to make gene modification robust.