Panobinostat HIV

Natural products originating from marine and plant materials are a rich source of chemical diversity and unique antimicrobials. Using an established in vitro model of HIV-1 latency, we screened 257 pure compounds from a marine natural product library and identified 4 (psammaplin A, aplysiatoxin, debromoaplysiatoxin, and previously-described alotaketal C) that induced expression of latent HIV-1 provirus in both cell line and primary cell models. Notably, aplysiatoxin induced similar levels of HIV-1 expression as prostratin but at up to 900-fold lower concentrations and without substantial effects on cell viability...

Histone deacetylase inhibitors (HDACi) modulate the transcriptional activity of all cells, including innate and adaptive immune cells. Therefore, we aimed to evaluate immunological effects of treatment with the HDACi panobinostat in HIV-infected patients during a clinical phase IIa latency reversal trial. Using flow cytometry, we investigated changes in T cell activation (CD69, CD38, HLA-DR) and the expression of CD39 and CTLA4 on regulatory T cells (Tregs). Whole-blood stimulations were performed and cytokine responses measured using Luminex...

We respond to Eyal et al.'s commentary focusing on how people living with HIV participating in HIV cure-related studies are defined. We argue that the types of participants enrolled in research cannot be dissociated from the study interventions, the types of anticipated risks, and the background standard of care. As the field of HIV cure research advances, more nuance and granularity will be needed to define research criteria and acceptable risk/benefit ratios for cure study participants, as well as specific tiered protocol designs that serve to protect various participant populations from untoward risks, especially in very early phase research with interventions known to have potentially serious toxicities...

Promising therapeutic approaches for eradicating HIV include transcriptional activation of provirus from latently infected cells using latency-reversing agents (LRAs) and immune-mediated clearance to purge reservoirs. Accurate detection of cells capable of producing viral antigens and virions, and the measurement of clearance of infected cells, is essential to assessing therapeutic efficacy. Here, we apply enhanced methodology extending the sensitivity limits for the rapid detection of subfemtomolar HIV gag p24 capsid protein in CD4+ T cells from ART-suppressed HIV+ individuals, and we show viral protein induction following treatment with LRAs...

There is growing interest in utilizing antibody-dependent cellular cytotoxicity (ADCC) to eliminate infected cells following reactivation from HIV-1 latency. A potential barrier is that HIV-1-specific ADCC antibodies decline in patients on long-term antiretroviral therapy (ART) and may not be sufficient to eliminate reactivated latently infected cells. It is not known whether reactivation from latency with latency-reversing agents (LRAs) could provide sufficient antigenic stimulus to boost HIV-1-specific ADCC...

Antiretroviral-free HIV remission requires substantial reduction of the number of latently infected cells and enhanced immune control of viremia. Latency-reversing agents (LRAs) aim to eliminate latently infected cells by increasing the rate of reactivation of HIV transcription, which exposes these cells to killing by the immune system. As LRAs are explored in clinical trials, it becomes increasingly important to assess the effect of an increased HIV reactivation rate on the decline of latently infected cells and to estimate LRA efficacy in increasing virus reactivation...

In an effort to clear persistent HIV infection and achieve a durable therapy-free remission of HIV disease, extensive pre-clinical studies and early pilot clinical trials are underway to develop and test agents that can reverse latent HIV infection and present viral antigen to the immune system for clearance. It is, therefore, critical to understand the impact of latency-reversing agents (LRAs) on the function of immune effectors needed to clear infected cells. We assessed the impact of LRAs on the function of natural killer (NK) cells, the main effector cells of the innate immune system...

The 'shock and kill' approach to cure human immunodeficiency virus (HIV) includes transcriptional induction of latent HIV-1 proviruses using latency-reversing agents (LRAs) with targeted immunotherapy to purge infected cells. The administration of LRAs (panobinostat or vorinostat) to HIV-1-infected individuals on antiretroviral therapy induces a significant increase in cell-associated unspliced (CA-US) HIV-1 RNA from CD4(+) T cells. However, it is important to discern whether the increases in CA-US HIV-1 RNA are due to limited or broad activation of HIV-1 proviruses...

BACKGROUND: The latent reservoir in resting CD4(+) T cells presents a major barrier to HIV cure. Latency-reversing agents are therefore being developed with the ultimate goal of disrupting the latent state, resulting in induction of HIV expression and clearance of infected cells. Histone deacetylase inhibitors (HDACi) have received a significant amount of attention for their potential as latency-reversing agents. RESULTS: Here, we have investigated the in vitro and systemic in vivo effect of panobinostat, a clinically relevant HDACi, on HIV latency...

BACKGROUND: While antiretroviral therapies have improved life expectancy and reduced viral loads in HIV-1-positive individuals, the cessation of treatment results in a rebound of viral replication. This suggests that a reservoir of latently-infected cells remains within these patients, the identity of which is ill-defined and therefore difficult to target therapeutically. Current strategies are aimed at using drugs such as histone deacetylase (HDAC) inhibitors to induce the expression of latent HIV-1 proviruses in order to activate and ultimately eradicate this reservoir of infected cells...

UNLABELLED: The existence of long-lived HIV-1-infected resting memory CD4 T cells is thought to be the primary obstacle to HIV-1 eradication. In the search for novel therapeutic approaches that may reverse HIV-1 latency, inhibitors of histone deacetylases (HDACis) have been tested to reactivate HIV-1 replication with the objective of rendering HIV-1-infected cells susceptible to elimination either by HIV-specific CD8 T cells or through virus-mediated cytopathicity. In the present study, we evaluated the efficiency of HDACis to reactivate HIV-1 replication from resting memory CD4 T cells isolated from aviremic long-term-treated HIV-1-infected subjects...

Viral reactivation from latently infected cells has become a promising therapeutic approach to eradicate HIV. Due to the complexity of the viral latency, combinations of efficient and available drugs targeting different pathways of latency are needed. In this work, we evaluated the effect of various combinations of bryostatin-1 (BRY) and novel histone deacetylase inhibitors (HDACIs) on HIV-reactivation and on cellular phenotype. The lymphocyte (J89GFP) or monocyte/macrophage (THP89GFP) latently infected cell lines were treated with BRY, panobinostat (PNB) and romidepsin (RMD) either alone or in combination...

Combination antiretroviral therapy (ART) is able to suppress HIV-1 replication to undetectable levels. However, the persistence of latent viral reservoirs allows for a rebound of viral load upon cessation of therapy. Thus, therapeutic strategies to eradicate the viral latent reservoir are critically needed. Employing a targeted RNAi screen, we identified the ubiquitin ligase BIRC2 (cIAP1), a repressor of the noncanonical NF-κB pathway, as a potent negative regulator of LTR-dependent HIV-1 transcription. Depletion of BIRC2 through treatment with small molecule antagonists known as Smac mimetics enhanced HIV-1 transcription, leading to a reversal of latency in a JLat latency model system...

Antiretroviral therapy (ART) is unable to cure HIV infection. The ability of HIV to establish a subset of latent infected CD4(+) T cells, which remain undetectable to the immune system, becomes a major roadblock to achieve viral eradication. Histone deacetylase inhibitors (HDACi) have been shown to potently induce the reactivation of latent HIV. Here, we show that a new thiol-based HDACi, the thioacetate-ω(γ-lactam carboxamide) derivative ST7612AA1, is a potent inducer of HIV reactivation. We evaluated HIV reactivation activity of ST7612AA1 compared to panobinostat (PNB), romidepsin (RMD) and vorinostat (VOR) in cell culture models of HIV-1 latency, in latently infected primary CD4(+) T lymphocytes and in PBMCs from HIV(+) patients...

Latency-reversing agents (LRAs), including histone deacetylase inhibitors (HDACi), are being investigated as a strategy to eliminate latency in HIV-infected patients on suppressive antiretroviral therapy. The effectiveness of LRAs in activating latent infection in HIV strains derived from the central nervous system (CNS) is unknown. Here we show that CNS-derived HIV-1 strains possess polymorphisms within and surrounding the Sp transcription factor motifs in the long terminal repeat (LTR). These polymorphisms result in decreased ability of the transcription factor specificity protein 1 to bind CNS-derived LTRs, reducing the transcriptional activity of CNS-derived viruses...

UNLABELLED: The pharmaceutical reactivation of dormant HIV-1 proviruses by histone deacetylase inhibitors (HDACi) represents a possible strategy to reduce the reservoir of HIV-1-infected cells in individuals treated with suppressive combination antiretroviral therapy (cART). However, the effects of such latency-reversing agents on the viral reservoir size are likely to be influenced by host immune responses. Here, we analyzed the immune factors associated with changes in proviral HIV-1 DNA levels during treatment with the potent HDACi panobinostat in a human clinical trial involving 15 cART-treated HIV-1-infected patients...

The human immunodeficiency virus type 1 (HIV-1) latent reservoir in resting CD4(+) T cells represents a major barrier to viral eradication. Small compounds capable of latency reversal have not demonstrated uniform responses across in vitro HIV-1 latency cell models. Characterizing compounds that demonstrate latency-reversing activity in resting CD4(+) T cells from aviremic patients ex vivo will help inform pilot clinical trials aimed at HIV-1 eradication. We have optimized a rapid ex vivo assay using resting CD4(+) T cells from aviremic HIV-1(+) patients to evaluate both the bioactivity and latency-reversing potential of candidate latency-reversing agents (LRAs)...

In a substudy of a clinical trial, we assessed whether activation of latent human immunodeficiency virus (HIV) by the histone deacetylase inhibitor panobinostat had detrimental effects on the central nervous system (CNS). Adults infected with HIV received oral panobinostat 20 mg 3 times per week every other week for 8 weeks. In cerebrospinal fluid (CSF), we assayed panobinostat concentration, HIV RNA, and the level of neuroinflammatory or degenerative biomarkers in 11 individuals before and during study therapy...

OBJECTIVE: To investigate the effect of the histone deacetylase inhibitor panobinostat on HIV-associated inflammation. DESIGN: Sub-study of a single-arm, phase I/II clinical trial. METHODS: HIV-infected adults on suppressive antiretroviral therapy received oral panobinostat 20 mg three times per week, every other week, for 8 weeks, that is, four cycles of treatment. Plasma levels of high-sensitivity C-reactive protein, matrix metalloproteinase 9, soluble CD40 ligand and interleukin-6 were determined using human ELISA kits...

Histone deacetylase inhibitors (HDACi) are being evaluated in a "shock-and-kill" therapeutic approach to reverse human immunodeficiency virus type-1 (HIV) latency from CD4(+) T cells. Using this approach, HDACi have induced HIV RNA synthesis in latently infected cells from some patients. The hope is that the increase in viral production will lead to killing of the infected cell either by the virus itself or by the patient's immune system, a "sterilizing cure." Although administered within the context of combination antiretroviral therapy, the infection of bystander cells remains a concern...