ABSTRACT
As a typical RNA virus, the genetic information on HIV-1 is entirely stored in RNA. The reverse transcription activity of HIV-1 reverse transcriptase (RT) plays a crucial role in the replication and transmission of the virus. Non-nucleoside RT inhibitors (NNRTIs) block the function of RT by binding to the RNA binding site on RT, with very few targeting viral RNA. In this study, by transforming planar conjugated ligands into a spiro structure, we convert classical Ru(II) DNA intercalators into a nonintercalator. This enables selective binding to HIV-1 transactivation response (TAR) RNA on the outer side of nucleic acids through dual interactions involving hydrogen bonds and electrostatic attraction, effectively inhibiting HIV-1 RT and serving as a selective fluorescence probe for TAR RNA.
Subject(s)
HIV Reverse Transcriptase , HIV-1 , Reverse Transcriptase Inhibitors , Ruthenium , HIV Reverse Transcriptase/antagonists & inhibitors , HIV Reverse Transcriptase/metabolism , Reverse Transcriptase Inhibitors/chemistry , Reverse Transcriptase Inhibitors/pharmacology , Reverse Transcriptase Inhibitors/metabolism , Ligands , HIV-1/enzymology , HIV-1/drug effects , Ruthenium/chemistry , Ruthenium/pharmacology , RNA, Viral/metabolism , RNA, Viral/chemistry , Spiro Compounds/chemistry , Spiro Compounds/pharmacology , Spiro Compounds/metabolism , Coordination Complexes/chemistry , Coordination Complexes/pharmacology , Coordination Complexes/chemical synthesis , Intercalating Agents/chemistry , Intercalating Agents/pharmacology , Molecular Structure , Humans , Anti-HIV Agents/chemistry , Anti-HIV Agents/pharmacology , HIV Long Terminal Repeat , Binding SitesABSTRACT
A DNA-intercalating Ru(II) polypyridyl complex [Ru(bpy)2(appo)]2+ (bpy=2,2'-bipyridine, appo=11-aminopteridino[6,7-f][1,10]phenanthrolin-13(12H)-one) has been synthesized and characterized by elemental analysis, electrospray mass spectra, (1)H NMR, UV/Vis spectrum, fluorescent spectrum and electrochemistry. The DNA-binding, photocleavage, and topoisomerase inhibition of the complex was studied. Interestingly, the complex binds to DNA via an intercalative mode with preference for GC sequences and cleaves the pBR322 DNA upon irradiation. In addition, the complex shows high inhibition activity against topoisomerase II by interfere the DNA religation.
Subject(s)
Enzyme Inhibitors/chemical synthesis , Intercalating Agents/chemical synthesis , Intercalating Agents/pharmacology , Organometallic Compounds/chemical synthesis , Organometallic Compounds/pharmacology , Topoisomerase II Inhibitors , DNA/radiation effects , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Hot Temperature , Intercalating Agents/chemistry , Luminescent Measurements , Nucleic Acid Denaturation , Organometallic Compounds/chemistry , Photochemistry , Spectrophotometry, Ultraviolet , ThermodynamicsABSTRACT
Many antitumor drugs act as topoisomerase inhibitors, and the inhibitions are usually related to DNA binding. Here we designed and synthesized DNA-intercalating Ru(II) polypyridyl complexes Delta--[Ru(bpy)(2)(uip)](2+) and Lambda-[Ru(bpy)(2)(uip)](2+) (bpy is 2,2'-bipyridyl, uip is 2-(5-uracil)-1H-imidazo[4,5-f][1,10]phenanthroline). The DNA binding, photocleavage, topoisomerase inhibition, and cytotoxicity of the complexes were studied. As we expected, the synthesized Ru(II) complexes can intercalate into DNA base pairs and cleave the pBR322 DNA with high activity upon irradiation. The mechanism studies reveal that singlet oxygen ((1)O(2)) and superoxide anion radical (O (2) (*-) ) may play an important role in the photocleavage. The inhibition of topoisomerases I and II by the Ru(II) complexes has been studied. The results suggest that both complexes are efficient inhibitors towards topoisomerase II by interference with the DNA religation and direct topoisomerase II binding. Both complexes show antitumor activity towards HELA, hepG2, BEL-7402, and CNE-1 tumor cells.