D10 is the first Tat activator available and the first LRA that targets an HIV protein, and induces strong HIV production by latent cell lines and latent cells from people living with HIV-1.
Abstract
Despite its efficiency to prevent viral multiplication, antiretroviral therapy does not affect HIV-1 latently-infected cells. These cells do not produce significant amounts of viruses and constitute HIV-1 reservoir. To purge this long-lived viral reservoir, the "shock and kill" strategy relies on the use of latency reversing agents (LRAs) to induce activation of latent cells. All LRAs developed until now target cellular proteins and are therefore not specific for HIV-infected cells. Here we present a new LRA that binds and activates HIV-1 Tat which is the key regulator for viral transcription and latency reversal. This molecule termed D10 was designed to bind to the major groove of the Tat protein, and found to activate Tat transcriptional activity by stabilizing the HIV transcription complex. This LRA induces strong HIV production by latent cell lines and latent cells from people living with HIV-1. On latent cells from PBMCs, D10 is active at ∼50 nM, the concentration required to stabilize HIV transcription complex. D10 is the first Tat activator available and the first LRA that targets an HIV protein.
ABSTRACT Human immunodeficiency virus type 1 (HIV-1) persists in latent reservoirs, mainly within CD4+ T cells, which are refractory to antiretroviral therapy, and can lead to rapid viral rebound upon treatment interruption. The “shock and kill” strategy aims to eliminate latent reservoirs by inducing viral transcription through latency-reversing agents (LRAs), thereby exposing infected cells to immune-mediated clearance. We developed and validated a simple, low-cost, and highly reproducible in vitro screening protocol to evaluate the efficacy and safety of LRAs, using a two-color flow cytometry assay on ACH2 cells, a well-characterized model of HIV-1 latency. Using this method, we identified PEP005 and CUDC-907 as the most potent LRAs across multiple experimental settings. Their reactivation capacity was further confirmed through transcriptomic analysis, which revealed a significant upregulation of viral RNA copies following stimulation. In addition, we collaborated with Dompé for using the Exscalate platform, an innovative computer-aided drug discovery approach, together with the experimental validation, which led to the identification of Tandutinib, a tyrosine kinase and mTOR inhibitor, as a novel LRA candidate with appreciable latency-reversing activity in the ACH2 model. While the ACH2 cell line does not fully recapitulate the complexity of HIV latency in vivo, it offers a robust and scalable system for early-stage screening and prioritization of candidate LRAs. Importantly, the future application of these LRAs in ex vivo samples derived from people living with HIV, with a particular focus on pediatric samples, will be crucial to deepen our understanding of latency reactivation in clinically relevant settings and age-specific immune environments. IMPORTANCE This study addresses a major obstacle to curing human immunodeficiency virus type 1 (HIV-1) infection: the persistence of latent viral reservoirs that are not eliminated by current therapies. We developed a simple and reproducible assay to identify compounds capable of reactivating latent virus, a key step in cure strategies. Using this approach, we identified effective latency-reversing compounds and, through collaboration with Dompé using the EXSCALATE platform, we also identified Tandutinib as a promising new candidate for further investigation. This study addresses a major obstacle to curing human immunodeficiency virus type 1 (HIV-1) infection: the persistence of latent viral reservoirs that are not eliminated by current therapies. We developed a simple and reproducible assay to identify compounds capable of reactivating latent virus, a key step in cure strategies. Using this approach, we identified effective latency-reversing compounds and, through collaboration with Dompé using the EXSCALATE platform, we also identified Tandutinib as a promising new candidate for further investigation.
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