title: Pyridine N-oxide derivatives inhibit viral transactivation by interfering with NF-kappaB binding.
abstract: Pyridine N-oxide derivatives represent a new class of anti-HIV compounds for which some members exclusively inhibit HIV-1 RT, whereas other members act, additionally or alternatively, at a post-integrational event in the replicative cycle of HIV. A prototype pyridine N-oxide derivative, JPL-32, inhibited tumor necrosis factor alpha (TNF-alpha)-induced HIV-1 expression in latently HIV-1-infected OM-10.1 and U1 cells, which could be reversed by the addition of N-acetyl-L-cysteine (NAC). The reversal of the antiviral activity of JPL-32 by NAC suggested the possible role of a redox-sensitive factor as target of inhibition. Indeed, when nuclear extracts of TNF-alpha-stimulated OM-10.1 and U1 cells cultured in the presence of JPL-32 were analyzed by an electrophoretic mobility shift assay (EMSA), a dose-dependent inhibition of DNA binding of nuclear NF-kappaB was observed, which could be reversed by the addition of NAC. JPL-32 did not inhibit the release and subsequent degradation of IkappaBalpha, nor did JPL-32 affect the nuclear translocation of NF-kappaB. EMSA revealed that the inhibition of the NF-kappaB DNA binding activity by JPL-32 could be reversed by the addition of reducing agents such as dithiothreitol or beta-mercaptoethanol. Moreover, JPL-32 was able to directly oxidize the thiol groups on the purified p50 subunit of recombinant NF-kappaB. The oxidative modification of the thiol groups on NF-kappaB by JPL-32 could be ascribed to the intracellular pro-oxidant effect of JPL-32. Consequently, JPL-32 was able to increase the intracellular glutathione (GSH) levels and to induce apoptosis in a dose-dependent way.
authors.affiliation: Rega Institute for Medical Research, Katholieke Universiteit Leuven, Belgium.
authors.forename: Miguel
authors.initials: M
authors.lastname: Stevens
authors.forename: Christophe
authors.initials: C
authors.lastname: Pannecouque
authors.forename: Erik
authors.initials: E
authors.lastname: De Clercq
authors.forename: Jan
authors.initials: J
authors.lastname: Balzarini
mesh_terms: D000818:Animals; D019380:Anti-HIV Agents / Q000737:chemistry / Q000494:pharmacology*; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D024202:Electrophoretic Mobility Shift Assay; D005978:Glutathione / Q000378:metabolism; D015497:HIV-1 / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D015394:Molecular Structure; D016328:NF-kappa B / Q000037:antagonists & inhibitors*; D018384:Oxidative Stress / Q000187:drug effects; D011485:Protein Binding; D011725:Pyridines / Q000737:chemistry / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014775:Virus Activation / Q000187:drug effects*
chemical_list: D019380:Anti-HIV Agents; D016328:NF-kappa B; D011725:Pyridines; D014409:Tumor Necrosis Factor-alpha; C013229:pyridine N-oxide; D005978:Glutathione