title: The new and less toxic protease inhibitor saquinavir-NO maintains anti-HIV-1 properties in vitro indistinguishable from those of the parental compound saquinavir.
abstract: Although, the antiviral activity, tolerability and convenience of protease inhibitors have improved significantly in recent years, toxicity-associated adverse events including diarrhea, lipid alterations, disturbance of glucose homeostasis and liver enzyme elevations still remain a major concern during treatment of HIV-1 patients. We have recently shown that the covalent attachment of the NO moiety to the HIV-1 protease inhibitor saquinavir (Saq-NO) reduces its toxicity. In this study, we evaluated in vitro the anti-HIV activity of Saq-NO vs. its parental compound Saq. Site directed mutants with the most frequently identified Saq associated resistance mutations and their combinations were generated on proviral AD8-based backbones. Phenotypic assays were conducted using wild type clinical isolates and fully replicating recombinant viruses with Saq and Saq-NO in parallel on purified CD4+ T cells. The following recombinant viruses were generated and tested: L33F, M46I, G48V, I54V, I84V + L90M, M46I + L90M, G48V + L90M, M46I + I54V + L90M, L33F + M46I + L90M. The fold change resistance compared to the wild type viruses was between 1.3 and 7 for all single mutants, between 3.4 and 20 for double mutants and between 16.7 and 28.5 for viruses carrying three mutations for both compounds. The results clearly demonstrate that Saq-NO maintains an anti-HIV-1 profile very similar to that of Saq. The possibility to reduce Saq associated side effects and to increase the concentration of the drug in vivo may allow a higher and possibly more effective dosage of Saq-NO in HIV-1-infected patients and to increase the genetic barrier of this PI thus impairing the selection of resistant clones.
authors.affiliation: Laboratory of Virology and Microbiology, University Vita-Salute San Raffaele, Milan, Italy. Canducci.filippo@hsr.it
authors.forename: Filippo
authors.initials: F
authors.lastname: Canducci
authors.forename: Elisa Rita
authors.initials: ER
authors.lastname: Ceresola
authors.forename: Diego
authors.initials: D
authors.lastname: Saita
authors.forename: Yousef
authors.initials: Y
authors.lastname: Al-Abed
authors.forename: Gianni
authors.initials: G
authors.lastname: Garotta
authors.forename: Massimo
authors.initials: M
authors.lastname: Clementi
authors.forename: Ferdinando
authors.initials: F
authors.lastname: Nicoletti
mesh_terms: D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000821:virology; D002470:Cell Survival / Q000187:drug effects; D017931:DNA Primers; D024882:Drug Resistance, Viral / Q000187:drug effects*; D015658:HIV Infections / Q000188:drug therapy* / Q000821:virology; D017320:HIV Protease Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D015497:HIV-1 / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D006801:Humans; D020128:Inhibitory Concentration 50; D016297:Mutagenesis, Site-Directed; D019258:Saquinavir / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: D017931:DNA Primers; D017320:HIV Protease Inhibitors; C557004:saquinavir-NO; D019258:Saquinavir