RNA interference is a powerful tool used to inhibit human immunodeficiency virus type 1 (HIV-1) replication in vitro. Almost all HIV-1 genes have been targets for
small interfering RNA (
siRNA) molecules, and HIV-1 replication can be specifically and successfully inhibited by this technique. RNA interference has been proposed as an alternative strategy to inhibit replication of
drug-resistant viruses that emerge during suboptimal antiretroviral
therapy for HIV-1. To investigate specific inhibition of
drug-resistant HIV-1 by RNA interference, we designed
siRNA molecules that recognize
codons 181-188 of the
reverse transcriptase (RT) gene of wild-type HIV-1 and HIV-1 carrying the M184V mutation, which confers high-level resistance to the RT inhibitor
lamivudine. Using viral variants with single point mutations at
codon 184, we measured the impact of these mutations on virus replication. We have demonstrated that
siRNA targeting either wild-type HIV-1 or M184V variants inhibits replication of the corresponding virus, but does not influence replication of virus with a mismatch in the targeted region. Combining two effective siRNAs did not show synergistic inhibitory effect on HIV-1 replication. However, a combination of
lamivudine and siRNA-M184V was very effective in inhibiting replication of both wild-type and variant M184V viruses in
mixed infection experiments. Taken together, these results demonstrate that RNA interference might be useful in the treatment of
drug-resistant HIV-1
infection.