Multi-targeting the entrance door to block HIV-1.

The multistep nature of HIV-1 entry provides multisite targeting at the entrance door of HIV-1 to cells. Blocking HIV-1 entry to its host cells has clear advantages over blocking subsequent stages in the life cycle of the virus. Indeed, potent cooperative and synergistic inhibition of HIV-1 proliferation has been observed in in vitro studies with several entry inhibitor combinations, interacting with different steps of the HIV-1-cell entry cascade. Targeting a compound to several steps of the viral-cell entry and also to subsequent steps in the viral life cycle promises an even more effective therapeutic, by reducing the probability of HIV-1 to develop resistance. Using one drug that can target multiple sites and/or steps in the viral life cycle will have obvious advantages in clinical use. In this article we review the multistep process of HIV-1 cell entry and the current repertoire of inhibitors of this critical stage in the viral life cycle, and introduce an example of multisite HIV-1 targeting of the cell entry and subsequent critical steps in the viral life cycle.