Specific inhibition of human immunodeficiency virus type 1 (HIV-1) integration in cell culture: Putative inhibitors of HIV-1 integrase

To study the effect of potential human immunodeficiency virus type 1 (HIV-1 ) integrase inhibitors during virus replication in cell culture, we used a modified nested Alu-PCR assay to quantify integrated HIV DNA in combination with the quantitative analysis of extrachromosomal HIV DNA. The two diketo acid integrase inhibitors (L-708,906 and L-731,988) blocked the accumulati on of integrated HIV-1 DNA in T cells following infection but did not alter levels of newly synthesized extrachromosomal HIV DNA. In contrast, we demo nstrated that L17 (a member of the bisaroyl hydrazine family of integrase i nhibitors) and AR177 (an oligonucleotide inhibitor) blocked the HIV replica tion cycle at, or prior to, reverse transcription, although both drug's inh ibited integrase activity in cell-free assays. Quercetin dihydrate (a flavo ne) was shown to not have any antiviral activity in our system despite repo rted anti-integration properties in cell-free assays. This refined Alu-PCR assay for HIV provirus is a useful tool for screening anti-integration comp ounds identified in biochemical assays for their ability to inhibit the acc umulation of integrated HIV DNA in cell culture, and it may be useful for s tudying the effects of these inhibitors in clinical trials.