ИСТИНА

I. Background: The human immunodeficiency virus type 1 integrase (IN) is an essential enzyme in the life cycle of the virus and is therefore an attractive target for the development of new antiviral drugs. Currently one integrase inhibitor, Isentress (Raltegravir), a selective strand transfer inhibitor, is approved by the FDA for the HIV infection treatment, and a few currently under clinical trials. However, resistance has already been observed in patients treated with Raltegravir, leading to virologic failure. There is therefore an ongoing constant need for the development of new inhibitors. II. Methods: We studied the effect of short single-strand oligonucleotides conjugated with hydrophobic molecules on the integrase catalytic activity. Step-by-step modifications in both oligonucleotide and hydrophobic parts of the conjugate were carried out and the modification influence on the inhibitory effect was determined. The most efficient inhibitors were then used to study HIV-1 replication inhibition in cell culture. Their delivery into cells was investigated by using different cell-penetrating peptides. One of them promotes an efficient cellular uptake of the conjugates. III. Results We have shown that short single-strand oligonucleotides conjugated with hydrophobic molecules inhibit the catalytic activity of recombinant HIV-1 integrase. These compounds may be considered as promising integrase inhibitors due to their capacity to interact with and to disrupt integrase complex with DNA. It was found that both parts of the conjugate, oligonucleotide and hydrophobic, play an important role in the integrase inhibition process. Conjugates of 11-mer phosphorothioate oligonucleotides with 6-carboxy-4,7,2',4',5',7'-hexachlorofluorescein (HEX) were found to be the most efficient inhibitors (IC50 20 nM), and might be considered as lead compounds for further development of integrase inhibitors. When complexed to the cell-penetrating peptide, the conjugates containing HEX or eosin exhibit a potent antiviral activity (IC50 < 10 nM) and low cytotoxicity. IV. Conclusion: Conjugates of short single-strand oligonucleotides with HEX or eosin may be considered as promising inhibitors of HIV replication. Their inhibitory activity against drug resistant strains of HIV-1 is under study.