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Abstract
Oxadiazols: a new class of rationally designed anti-HIV compounds targeting nuclear localization signal of the viral matrix protein
Haffar O.1, Dubrovsky L.2, Bukrinsky M.2
1International Therapeutics Incorporated, Seattle, United States of America, 2The George Washington University, Washington, United States of America
Introduction: Despite recent progress in anti-HIV therapy, drug toxicity and emergence of drug-resistant isolates during long-term treatment of HIV-infected patients necessitate the search for new targets that can be used to develop novel anti-viral agents. One such target is the process of nuclear translocation of the HIV pre-integration complex. Previously, we described a class of arylene bis(methylketone) compounds that inhibit HIV-1 nuclear import by targeting the nuclear localization signal (NLS) in the matrix protein (MA). Here, we report a different class of compounds targeting MA NLS that were selected using computer-assisted drug design.
Methods: Anti-HIV activity was tested in PBMCs, monocyte-derived macrophages, and ex vivo cultured lymphoid tissues. Viral replication was analyzed by measuring RT activity. Specific effect on nuclear transport was demonstrated by measuring full-length HIV-1 DNA in the nucleus and cytoplasm by real-time PCR. Immunofluorescence analysis of the cells infected with the virus labeled with Alexa Fluor 488-5-dUTP during endogenous reverse transcription was used to visualize virus translocation from the cytoplasm to the nucleus in infected macrophages.
Results: The lead compound from this group, ITI-367, showed potent anti-HIV activity in cultures of T lymphocytes and macrophages, and also inhibited HIV-1 replication in ex vivo cultured lymphoid tissue. Analysis by real-time PCR demonstrated substantial reduction of nuclear HIV-1 DNA in ITI-367-treated macrophages, with minimal decrease in total HIV-1 DNA. Consistent with this result, immunofluorescent microscopy using fluorescently labeled HIV-1 demonstrated retention of the viral DNA in the cytoplasm of drug-treated macrophages, supporting the notion that the drug inhibited HIV nuclear import. The virus that acquired resistance to ITI-002, a compound from the arylene bis(methylketone) class, was partially resistant to ITI-367, supporting the notion that these drugs share the mechanism of action.
Conclusions: Compounds inhibiting HIV nuclear import are attractive additions to multidrug cocktails. Oxadiazols may be good candidates for further development.
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