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13th International HIV Drug Resistance Workshop8–12 June 2004, Tenerife Sur-Costa Adeje, Canary Islands, Spain |
BACKGROUND: Styrylquinolines (SQLs) have been reported to be HIV-1 integrase inhibitors in vitro. Although integrase is unique to the virus and does not have a host cell counterpart, numerous integrase inhibitors have been shown to inhibit multiple viral and non viral proteins. To get further insights into the SQL target, our aim was to determine the in vitro development of HIV-1 resistance to FZ41 lead compound of the SQLs family, and evaluate fitness.
METHODS: CEM 4fx cells were infected with NL43 wild-type virus in the presence of increasing concentrations of FZ41. Resistant viruses obtained were sequenced. Identified mutations were introduced into the NL43 strain by site-directed mutagenesis and phenotypically evaluated by determining FZ41 IC50 on P4 cells. Selected HIV-1 strains in the presence of FZ41 were examined for their ability to replicate in HeLa P4 cells in comparison with NL43 in the absence of drug.
RESULTS: Two mutants emerged after incubation in step by step increased FZ41 concentrations and a final selection with 20 µM: one contained a single mutation C280Y, the other contained two mutations V165I-V249I. IC50s confirmed that the selected mutations conferred resistance to SQLs. Double mutant IC50 was nearly ninefold higher than that of wild-type virus. IC50 of the other one, C280Y mutant was fivefold higher than that of the wild-type. Of note, IC50 of the diketo analogue L731-988 was not modified for either of these two mutants. Replication kinetics of the mutants, as evaluated by p24 measurements, was lower relative to the replication of HIV-1 NL43 strain. Seven days post-infection, for, respectively, C280Y and V165I-V249I mutants, only 68% and 5% of the p24 level of the control was detected.
CONCLUSIONS: Selection of resistance FZ41 is associated with the emergence of mutations at three residues within HIV-1 integrase, that have been previously involved for two of them with integrase non-catalytic function or drug interaction. With an in vitro resistance pattern different from those of diketo analogues, SQLs represent a new family of integrase inhibitors.
PRESENTING AUTHOR: A Chéret
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2004-06-08
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