panobinostat and HIV-Infections

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Topics: Animals; British Columbia; CD4-Positive T-Lymphocytes; HIV Infections; HIV-1; Porifera; Sesterterpenes; Virus Latency

Despite the advances in Human Immunodeficiency Virus (HIV) treatment, the cure for all HIV patients still poses a major challenge, which needs to be surpassed in the coming years. Among the strategies pursuing this aim, the 'kick-and-kill' approach, which involves the reactivation and elimination of a latent HIV reservoir that resides in some CD4

Topics: Anti-HIV Agents; CD4-Positive T-Lymphocytes; Histone Deacetylase Inhibitors; HIV Infections; HIV-1; Humans; Molecular Structure; Virus Latency

To summarize the state of chronic, treated HIV infection and its contribution to accelerated aging, and to evaluate recent research relevant to the study and treatment of aging and senescence.. Chronic treated HIV-1 infection is associated with significant risk of end-organ impairment, non-AIDS-associated malignancies, and accelerated physiologic aging. Coupled with the chronologic aging of the HIV-1-positive population, the development of therapies that target these processes is of great clinical importance. Age-related diseases are partly the result of cellular senescence. Both immune and nonimmune cell subsets are thought to mediate this senescent phenotype, a state of stable cell cycle arrest characterized by sustained release of pro-inflammatory mediators. Recent research in the field of aging has identified a number of 'senotherapeutics' to combat aging-related diseases, pharmacologic agents that act either by selectively promoting the death of senescent cells ('senolytics') or modifying senescent phenotype ('senomorphics').. Senescence is a hallmark of aging-related diseases that is characterized by stable cell cycle arrest and chronic inflammation. Chronic HIV-1 infection predisposes patients to aging-related illnesses and is similarly marked by a senescence-like phenotype. A better understanding of the role of HIV-1 in aging will inform the development of therapeutics aimed at eliminating senescent cells that drive accelerated physiologic aging.

Topics: Aging; Aniline Compounds; Antibiotics, Antineoplastic; Antineoplastic Agents; Antiretroviral Therapy, Highly Active; Bridged Bicyclo Compounds, Heterocyclic; Cardiovascular Diseases; CD4-CD8 Ratio; Cell Cycle Checkpoints; Cellular Senescence; Histone Deacetylase Inhibitors; HIV Infections; HIV-1; Humans; Inflammation; Janus Kinases; Nitriles; Panobinostat; Pyrazoles; Pyrimidines; Sirolimus; Sulfonamides; T-Lymphocyte Subsets

Despite the success of antiretroviral therapy (ART), there is currently no HIV cure and treatment is life long. HIV persists during ART due to long-lived and proliferating latently infected CD4+ T cells. One strategy to eliminate latency is to activate virus production using latency reversing agents (LRAs) with the goal of triggering cell death through virus-induced cytolysis or immune-mediated clearance. However, multiple studies have demonstrated that activation of viral transcription alone is insufficient to induce cell death and some LRAs may counteract cell death by promoting cell survival. Here, we review new approaches to induce death of latently infected cells through apoptosis and inhibition of pathways critical for cell survival, which are often hijacked by HIV proteins. Given advances in the commercial development of compounds that induce apoptosis in cancer chemotherapy, these agents could move rapidly into clinical trials, either alone or in combination with LRAs, to eliminate latent HIV infection.

Topics: Anti-HIV Agents; Bryostatins; CD4-Positive T-Lymphocytes; Depsipeptides; HIV Infections; HIV-1; Humans; Hydroxamic Acids; Indoles; Panobinostat; Phosphoinositide-3 Kinase Inhibitors; Proto-Oncogene Proteins c-bcl-2; Virus Activation; Virus Latency; Vorinostat

Histone deacetylase inhibitors (HDACi) have proven to induce HIV-RNA and antigen expression in resting CD4 T cells of antiretroviral therapy (ART)-treated HIV-infected individuals. However, to achieve viral eradication, immune clearance must follow latency reversal, and thus it is essential to understand the impact of latency reversal agents on immune function.. Here we evaluate the impact of in-vivo administration of vorinostat (VOR) and panobinostat (PNB) during clinical trials on natural killer (NK) cell function and phenotype.. Cryopreserved peripheral blood mononuclear cells from HIV-positive participants receiving VOR (NCT01319383) or PNB (NCT01680094) were selected to assess the impact of the drugs on cell composition, activation, NK cell phenotype (CD16, NKG2D, NKp30, NKp46 and DNAM-1), cytotoxic activity (CD107a), and interferon (IFN)-γ production.. No impairment of NK cell function was observed during treatment with either VOR or PNB. An increase in the frequency of CD3CD56 NK cells was consistently observed. Interestingly, after VOR administration, NK cells increased expression of NKp46 and CD16, and showed improved degranulation and IFN-γ production capacity. Moreover, taking together VOR and PNB samples, HIV DNA levels in CD4 cells were negatively correlated with NK cell frequency and NK cell expression of CD16.. In-vivo treatment with HDACi does not have measurable negative effects on NK cell function, with some evidence of improved function in vitro. These results have important implications for potential combinatorial approaches to target HIV reservoirs, suggesting that the use of HDACis as a latency reversal agent could be paired with interventions to enhance NK cell activity or recruitment.

Topics: Histone Deacetylase Inhibitors; HIV Infections; Humans; Killer Cells, Natural; Panobinostat; Treatment Outcome; Vorinostat

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. Here we use single-genome sequencing to find that the RNA transcripts observed following LRA administration are genetically diverse, indicating activation of transcription from an extensive range of proviruses. Defective sequences are more frequently found in CA HIV-1 RNA than in HIV-1 DNA, which has implications for developing an accurate measure of HIV-1 reservoir size. Our findings provide insights into the effects of panobinostat and vorinostat as LRAs for latent HIV-1.

Topics: Adult; Anti-HIV Agents; CD4-Positive T-Lymphocytes; DNA, Viral; Drug Administration Schedule; HIV Infections; HIV-1; Humans; Hydroxamic Acids; Indoles; Middle Aged; Panobinostat; RNA, Viral; Viremia; Virus Latency; Vorinostat

To investigate the effect of the histone deacetylase inhibitor panobinostat on HIV-associated inflammation.. Sub-study of a single-arm, phase I/II clinical trial.. 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. Soluble endothelia selectin (E-selectin) was measured by a multiplex immunoassay. Total monocyte count, phenotype changes on monocytes and monocyte histone acetylation were analyzed using flow cytometry. Whole-genome expression in peripheral blood mononuclear cells was analyzed at baseline and on-panobinostat employing the Affymetrix Human Transcriptome Array 2.0 microarray assay. Changes from baseline were analyzed using Wilcoxon signed-rank test. For the gene-expression analyses, fold-changes, P values and false detection rate were computed using TAC software.. Panobinostat treatment led to significant reductions in multiple established plasma markers of inflammation. Notably, high-sensitivity C-reactive protein decreased by a median of 58% during treatment and this change persisted for 4 weeks after treatment. Plasma levels of interleukin-6, matrix metalloproteinase 9, E-selectin and soluble CD40 ligand also significantly decreased on and/or postpanobinostat. Additionally, we observed a significant reduction in the proportions of intermediate monocytes and tissue factor-positive monocytes. This suppression of cardiovascular risk biomarkers was associated with a prominent reduction in the expression of genes related to inflammation and atherosclerosis.. Collectively, these data indicate that panobinostat may have therapeutic potential to target excess inflammation in HIV patients with high cardiovascular risk.

Topics: Adult; Anti-Retroviral Agents; Biomarkers; Cardiovascular Diseases; Histone Deacetylase Inhibitors; HIV Infections; Humans; Hydroxamic Acids; Indoles; Inflammation; Panobinostat; Treatment Outcome

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. We observed that the magnitude, breadth, and cytokine secretion profile of HIV-1-specific CD8 T cell responses were unrelated to changes in HIV-1 DNA levels in CD4 T cells during panobinostat treatment. In contrast, the proportions of CD3(-) CD56(+) total NK cells and CD16(+) CD56(dim) NK cells were inversely correlated with HIV-1 DNA levels throughout the study, and changes in HIV-1 DNA levels during panobinostat treatment were negatively associated with the corresponding changes in CD69(+) NK cells. Decreasing levels of HIV-1 DNA during latency-reversing treatment were also related to the proportions of plasmacytoid dendritic cells, to distinct expression patterns of interferon-stimulated genes, and to the expression of the IL28B CC genotype. Together, these data suggest that innate immune activity can critically modulate the effects of latency-reversing agents on the viral reservoir and may represent a target for future immunotherapeutic interventions in HIV-1 eradication studies.. Currently available antiretroviral drugs are highly effective in suppressing HIV-1 replication, but the virus persists, despite treatment, in a latent form that does not actively express HIV-1 gene products. One approach to eliminate these cells, colloquially termed the "shock-and-kill" strategy, focuses on the use of latency-reversing agents that induce active viral gene expression in latently infected cells, followed by immune-mediated killing. Panobinostat, a histone deacetylase inhibitor, demonstrated potent activities in reversing HIV-1 latency in a recent pilot clinical trial and reduced HIV-1 DNA levels in a subset of patients. Interestingly, we found that innate immune factors, such as natural killer cells, plasmacytoid dendritic cells, and the expression patterns of interferon-stimulated genes, were most closely linked to a decline in the HIV-1 DNA level during treatment with panobinostat. These data suggest that innate immune activity may play an important role in reducing the residual reservoir of HIV-1-infected cells.

Topics: Antigens, CD; Antiretroviral Therapy, Highly Active; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Cell Count; Dendritic Cells; DNA, Viral; Drug Administration Schedule; Gene Expression; Genotype; Histone Deacetylase Inhibitors; Histone Deacetylases; HIV Infections; HIV-1; Humans; Hydroxamic Acids; Immunity, Innate; Indoles; Interferons; Interleukins; Killer Cells, Natural; Panobinostat; Virus Latency

Despite antiretroviral treatment efficacy, it does not lead to the complete eradication of HIV infection. Consequently, reactivation of the virus from latently infected cell reservoirs is a major challenge toward cure efforts. Two strategies targeting viral latency are currently under investigation: the "shock and kill" and the "block and lock." The "Block and Lock" methodology aims to control HIV-1 latency reactivation, promoting a functional cure. We utilized the CRISPR/dCas9-KRAB platform, which was initially developed to suppress cellular genes transcription, to block drug-induced HIV-1 reactivation in latently infected T cells and myeloid cells.. We identified a set of five sgRNAs targeting the HIV-1 proviral genome (LTR1-LTR5), having the lowest nominated off-target activity, and transduced them into the latently infected lymphoid (J-Lat 10.6) and myeloid (U1) cell lines. One of the sgRNAs (LTR5), which binds specifically in the HIV-1 LTR NFκB binding site, was able to promote robust repression of HIV-1 reactivation in latently infected T cells stimulated with Phorbol 12-Myristate 13-Acetate (PMA) and Ingenol B (IngB), both potent protein kinase C (PKC) stimulators. Reactivation with HDAC inhibitors, such as SAHA and Panobinostat, showed the same strong inhibition of reactivation. Additionally, we observed a hundred times reduction of HIV-1 RNA expression levels in the latently infected myeloid cell line, U1 induced with IngB.. Taken together, our results show that the KRAB fused CRISPR/dCas9 system can robustly prevent the HIV-1 latency reactivation process, mediated by PMA or IngB and SAHA or Panobinostat, both in myeloid and lymphoid HIV-1 latently infected cells. In addition, we demonstrated that KRAB repressor protein is crucial to reactivation resistance phenotype, and we have identified some useful hotspots sequences in HIV-1 LTR for the design sgRNAs.

Topics: Clustered Regularly Interspaced Short Palindromic Repeats; HIV Infections; HIV-1; Humans; Myeloid Cells; Panobinostat; Virus Activation; Virus Latency

Topics: CD4-Positive T-Lymphocytes; Histone Deacetylase Inhibitors; HIV Infections; HIV-1; Humans; Interleukin-15; Killer Cells, Natural; Panobinostat; Virus Activation; Virus Latency

Highly active antiretroviral therapy (HAART) can turn human immunodeficiency virus-1 (HIV-1) infection into a controllable chronic disease, but because of the presence of an HIV reservoir, it cannot completely eliminate the virus in HIV-infected patients. The activation of latent reservoirs is the key to the successful treatment of acquired immune deficiency syndrome (AIDS). As a class of latency-reversing agents (LRAs), histone deacetylase inhibitors (HDACis), such as panobinostat, have been the most widely investigated, but most of them have resulted in only a modest and transient activation of HIV latency. To improve the potency of latency activation, an injectable peptide self-assembly nanoparticle loaded with panobinostat (PNP-P) was designed with the ability to efficiently penetrate the cell to achieve better drug delivery and activation of latent HIV. The results confirmed that these nanoparticles could activate latently infected cells

Topics: CD4-Positive T-Lymphocytes; HIV Infections; HIV-1; Humans; Hydroxamic Acids; Indoles; Leukocytes, Mononuclear; Nanoparticles; Panobinostat; Peptides; Virus Activation; Virus Latency

The major obstacle impeding human immunodeficiency virus-1 (HIV-1) eradication in antiretroviral treatment (ART) treated HIV-1 subjects is the establishment of long-lived latently infected resting CD4. J89GFP lymphocyte and THP89GFP monocyte derived cell lines latently infected with HIV-1 p89GFP were used as an in vitro model of latency for our study. Viability assays by 3-(4-5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) were performed to determine the working concentrations of dendrimers and LRAs. Both cell lines were treated with G1-S4, G2-S16 and G3-S16 either alone or in combination with bryostatin (BRY), romidepsin (RMD) or panobinostat (PNB) for 24 and 48 h. The expression pattern of GFP was measured by flow cytometry and referred as measure of viral reactivation.. The combination treatment of the dendrimers with the protein kinase C (PKC) agonist did not modify the antilatency activity in J89GFP lymphocyte cell line. Interestingly enough, G3-S16 dendrimer alone and its combination with BRY, RMD or PNB showed a significant increased expression of GFP in the THP89GFP monocyte cell line.. We showed for the first time that nanoparticles, in this case, G3-S16 anionic carbosilan dendrimer may play an important role in new treatments against HIV-1 infection.

Topics: Adjuvants, Immunologic; Anti-HIV Agents; Bryostatins; Cell Line; Cell Survival; Dendrimers; Depsipeptides; Drug Liberation; Drug Therapy, Combination; HIV Infections; HIV-1; Humans; Lymphocytes; Monocytes; Panobinostat; Particle Size; Polyelectrolytes; Polymers; Silanes; Surface Properties

Natural products originating from marine and plant materials are a rich source of chemical diversity and unique antimicrobials. Using an established

Topics: Anti-HIV Agents; Aquatic Organisms; Biological Products; CD4-Positive T-Lymphocytes; Cell Line; Cell Survival; Disulfides; Drug Discovery; High-Throughput Screening Assays; HIV Infections; HIV-1; Humans; Panobinostat; Phorbol Esters; Proviruses; Tyrosine; Virus Activation; Virus Latency

Persistence of latent HIV-1 in macrophages (MACs) and T-helper lymphocytes (THLs) remain a major therapeutic challenge. Currently available latency reversing agents (LRAs) are not very effective in vivo. Therefore, understanding of physiologic mechanisms that dictate HIV-1 latency/reactivation in reservoirs is clearly needed. Mesenchymal stromal/stem cells (MSCs) regulate the function of immune cells; however, their role in regulating virus production from latently-infected MACs & THLs is not known. We documented that exposure to MSCs or their conditioned media (MSC-CM) rapidly increased HIV-1 p24 production from the latently-infected U1 (MAC) & ACH2 (THL) cell lines. Exposure to MSCs also increased HIV-1 long terminal repeat (LTR) directed gene expression in the MAC and THL reporter lines, U937-VRX and J-Lat (9.2), respectively. MSCs exposed to CM from U1 cells (U1-CM) showed enhanced migratory ability towards latently-infected cells and retained their latency-reactivation potential. Molecular studies showed that MSC-mediated latency-reactivation was dependent upon both the phosphatidyl inositol-3-kinase (PI3K) and nuclear factor-κB (NFκB) signaling pathways. The pre-clinically tested inhibitors of PI3K (PX-866) and NFκB (CDDO-Me) suppressed MSC-mediated HIV-1 reactivation. Furthermore, coexposure to MSC-CM enhanced the latency-reactivation efficacy of the approved LRAs, vorinostat and panobinostat. Our findings on MSC-mediated latency-reactivation may provide novel strategies against persistent HIV-1 reservoirs.

Topics: Anti-HIV Agents; Cell Line; Culture Media, Conditioned; Drug Evaluation, Preclinical; Gene Expression Regulation, Viral; Gonanes; HIV Infections; HIV Long Terminal Repeat; HIV-1; Humans; Mesenchymal Stem Cells; NF-kappa B; Oleanolic Acid; Panobinostat; Phosphatidylinositol 3-Kinases; Signal Transduction; Virus Activation; Virus Latency; Vorinostat

Topics: Adaptive Immunity; Adult; Anti-Retroviral Agents; Antibody-Dependent Cell Cytotoxicity; Female; HIV Antibodies; HIV Infections; HIV-1; Humans; Hydroxamic Acids; Indoles; Male; Middle Aged; Panobinostat; Time Factors

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. However, whether the extent of HIV reactivation is a good predictor of the rate of decline of the number of latently infected cells is dependent on a number of factors. Our modeling shows that the mechanisms of maintenance and clearance of the reservoir, the life span of cells with reactivated HIV, and other factors may significantly impact the relationship between measures of HIV reactivation and the decline in the number of latently infected cells. The usual measures of HIV reactivation are the increase in cell-associated HIV RNA (CA RNA) and/or plasma HIV RNA soon after administration. We analyze two recent studies where CA RNA was used to estimate the impact of two novel LRAs, panobinostat and romidepsin. Both drugs increased the CA RNA level 3- to 4-fold in clinical trials. However, cells with panobinostat-reactivated HIV appeared long-lived (half-life > 1 month), suggesting that the HIV reactivation rate increased by approximately 8%. With romidepsin, the life span of cells that reactivated HIV was short (2 days), suggesting that the HIV reactivation rate may have doubled under treatment.

Topics: Anti-HIV Agents; Depsipeptides; HIV Infections; HIV-1; Humans; Hydroxamic Acids; Indoles; Models, Theoretical; Panobinostat; RNA, Viral; Transcription, Genetic; Viremia; Virus Activation; Virus Latency

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. These mutations result in CNS-derived viruses being less responsive to activation by the HDACi panobinostat and romidepsin compared with lymphoid-derived viruses from the same subjects. Our findings suggest that HIV-1 strains residing in the CNS have unique transcriptional regulatory mechanisms, which impact the regulation of latency, the consideration of which is essential for the development of HIV-1 eradication strategies.

Topics: Adult; Brain; CD4-Positive T-Lymphocytes; Central Nervous System; Cohort Studies; Depsipeptides; Histone Deacetylase Inhibitors; HIV Infections; HIV-1; Humans; Hydroxamic Acids; Indoles; Jurkat Cells; Male; Middle Aged; Panobinostat; Polymorphism, Genetic; Terminal Repeat Sequences; Transcriptional Activation; Virus Latency

Cessation of highly active antiretroviral therapy (HAART) in HIV-infected individual leads to a rebound of viral replication due to reactivation of a viral reservoir composed largely of latently infected memory CD4(+) T cells. Efforts to deplete this reservoir have focused on reactivation of transcriptionally silent latent proviruses. HIV provirus transcription depends critically on the positive transcription elongation factor b (P-TEFb), whose core components are cyclin-dependent kinase 9 (CDK9) and cyclin T1. In resting CD4(+) cells, the functional levels of P-TEFb are extremely low. Cellular activation upregulates cyclin T1 protein levels and CDK9 T-loop (T186) phosphorylation. The broad-spectrum histone deacetylase inhibitors (HDACis) vorinostat and panobinostat have been shown to reactivate latent virus in vivo in HAART-treated individuals. In this study, we have found that vorinostat and panobinostat activate P-TEFb in resting primary CD4(+) T cells through induction of CDK9 T-loop phosphorylation. In contrast, tacedinaline and romidepsin, HDAC 1 and 2 inhibitors, were unable to activate CDK9 T-loop phosphorylation. We used a CCL19 primary CD4(+) T-cell model HIV latency to assess the correlation between induction of CDK9 T-loop phosphorylation and reactivation of latent HIV virus by HDACis. Vorinostat and panobinostat treatment of cells harboring latent HIV increased CDK9 T-loop phosphorylation and reactivation of latent virus, whereas tacedinaline and romidepsin failed to induce T-loop phosphorylation or reactivate latent virus. We conclude that the ability of vorinostat and panobinostat to induce latent HIV is, in part, likely due to the ability of the broad-spectrum HDACis to upregulate P-TEFb through increased CDK9 T-loop phosphorylation.

Topics: Antiretroviral Therapy, Highly Active; Benzamides; CD4-Positive T-Lymphocytes; Cells, Cultured; Cyclin T; Cyclin-Dependent Kinase 9; Depsipeptides; Enzyme Activation; Gene Expression Regulation, Viral; Histone Deacetylase Inhibitors; HIV Infections; HIV-1; Humans; Hydroxamic Acids; Indoles; Panobinostat; Phenylenediamines; Phosphorylation; Positive Transcriptional Elongation Factor B; Proviruses; Virus Activation; Virus Latency; Virus Replication; Vorinostat

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.. Here, we have investigated the in vitro and systemic in vivo effect of panobinostat, a clinically relevant HDACi, on HIV latency. We showed that panobinostat induces histone acetylation in human PBMCs. Further, we showed that panobinostat induced HIV RNA expression and allowed the outgrowth of replication-competent virus ex vivo from resting CD4(+) T cells of HIV-infected patients on suppressive antiretroviral therapy (ART). Next, we demonstrated that panobinostat induced systemic histone acetylation in vivo in the tissues of BLT humanized mice. Finally, in HIV-infected, ART-suppressed BLT mice, we evaluated the effect of panobinostat on systemic cell-associated HIV RNA and DNA levels and the total frequency of latently infected resting CD4(+) T cells. Our data indicate that panobinostat treatment resulted in systemic increases in cellular levels of histone acetylation, a key biomarker for in vivo activity. However, panobinostat did not affect the levels of cell-associated HIV RNA, HIV DNA, or latently infected resting CD4(+) T cells.. We have demonstrated robust levels of systemic histone acetylation after panobinostat treatment of BLT humanized mice; and we did not observe a detectable change in the levels of cell-associated HIV RNA, HIV DNA, or latently infected resting CD4(+) T cells in HIV-infected, ART-suppressed BLT mice. These results are consistent with the modest effects noted in vitro and suggest that combination therapies may be necessary to reverse latency and enable clearance. Animal models will contribute to the progress towards an HIV cure.

Topics: Acetylation; Animals; Anti-HIV Agents; CD4-Positive T-Lymphocytes; DNA, Viral; Histone Deacetylase Inhibitors; Histones; HIV Infections; HIV-1; Humans; Hydroxamic Acids; Indoles; Leukocytes, Mononuclear; Mice; Mice, Transgenic; Panobinostat; RNA, Viral; Virus Activation; Virus Latency; Virus Replication

Despite the extraordinary success of HIV-1 antiretroviral therapy in prolonging life, infected individuals face lifelong therapy because of a reservoir of latently-infected cells that harbor replication competent virus. Recently, compounds have been identified that can reverse HIV-1 latency in vivo. These latency- reversing agents (LRAs) could make latently-infected cells vulnerable to clearance by immune cells, including cytolytic CD8+ T cells. We investigated the effects of two leading LRA classes on CD8+ T cell phenotype and function: the histone deacetylase inhibitors (HDACis) and protein kinase C modulators (PKCms). We observed that relative to HDACis, the PKCms induced much stronger T cell activation coupled with non-specific cytokine production and T cell proliferation. When examining antigen-specific CD8+ T cell function, all the LRAs except the HDACi Vorinostat reduced, but did not abolish, one or more measurements of CD8+ T cell function. Importantly, the extent and timing of these effects differed between LRAs. Panobinostat had detrimental effects within 10 hours of drug treatment, whereas the effects of the other LRAs were observed between 48 hours and 5 days. These observations suggest that scheduling of LRA and CD8+ T cell immunotherapy regimens may be critical for optimal clearance of the HIV-1 reservoir.

Topics: Adult; CD4-Positive T-Lymphocytes; Cell Proliferation; Cytokines; Histone Deacetylase Inhibitors; HIV Infections; HIV-1; Humans; Hydroxamic Acids; Indoles; Lymphocyte Activation; Male; Middle Aged; Panobinostat; Protein Kinase Inhibitors; T-Lymphocytes, Cytotoxic; Virus Latency; Vorinostat

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). Using this assay, we characterize the properties of two candidate compounds from promising LRA classes, ingenol 3,20-dibenzoate (a protein kinase C agonist) and panobinostat (a histone deacetylase inhibitor), in cells from HIV-1(+) antiretroviral therapy (ART)-treated aviremic participants, including the effects on cellular activation and cytotoxicity. Ingenol induced viral release at levels similar to those of the positive control (CD3/28 receptor stimulation) in cells from a majority of participants and represents an exciting LRA candidate, as it combines a robust viral reactivation potential with a low toxicity profile. At concentrations that blocked histone deacetylation, panobinostat displayed a wide range of potency among participant samples and consistently induced significant levels of apoptosis. The protein kinase C agonist ingenol 3,20-dibenzoate demonstrated significant promise in a rapid ex vivo assay using resting CD4(+) T cells from treated HIV-1-positive patients to measure latent HIV-1 reactivation.

Topics: Adult; Anti-HIV Agents; Antiretroviral Therapy, Highly Active; Case-Control Studies; CD4-Positive T-Lymphocytes; Diterpenes; DNA, Viral; Enzyme Activators; Female; Histone Deacetylase Inhibitors; HIV Infections; HIV-1; Humans; Hydroxamic Acids; Indoles; Male; Middle Aged; Panobinostat; Primary Cell Culture; Protein Kinase C; Viral Load; Virus Activation; Virus Latency

HIV-1 persists in a latent reservoir despite antiretroviral therapy (ART). This reservoir is the major barrier to HIV-1 eradication. Current approaches to purging the latent reservoir involve pharmacologic induction of HIV-1 transcription and subsequent killing of infected cells by cytolytic T lymphocytes (CTLs) or viral cytopathic effects. Agents that reverse latency without activating T cells have been identified using in vitro models of latency. However, their effects on latently infected cells from infected individuals remain largely unknown. Using a new ex vivo assay, we demonstrate that none of the latency-reversing agents (LRAs) tested induced outgrowth of HIV-1 from the latent reservoir of patients on ART. Using a quantitative reverse transcription PCR assay specific for all HIV-1 mRNAs, we demonstrate that LRAs that do not cause T cell activation do not induce substantial increases in intracellular HIV-1 mRNA in patient cells; only the protein kinase C agonist bryostatin-1 caused significant increases. These findings demonstrate that current in vitro models do not fully recapitulate mechanisms governing HIV-1 latency in vivo. Further, our data indicate that non-activating LRAs are unlikely to drive the elimination of the latent reservoir in vivo when administered individually.

Topics: Anti-HIV Agents; Azepines; Bryostatins; CD4-Positive T-Lymphocytes; Cell Cycle Proteins; Depsipeptides; Disulfiram; Histone Deacetylase Inhibitors; HIV Infections; HIV-1; Humans; Hydroxamic Acids; Indoles; Ionomycin; Lymphocyte Activation; Nuclear Proteins; Panobinostat; Tetradecanoylphorbol Acetate; Transcription Factors; Triazoles; Virus Latency; Vorinostat

Resting memory CD4+ T-cells harboring latent HIV proviruses represent a critical barrier to viral eradication. Histone deacetylase inhibitors (HDACis), such as suberanilohydroxamic acid (SAHA), romidepsin, and panobinostat have been shown to induce HIV expression in these resting cells. Recently, it has been demonstrated that the low levels of viral gene expression induced by a candidate HDACi may be insufficient to cause the death of infected cells by viral cytopathic effects, necessitating their elimination by immune effectors, such as cytotoxic T-lymphocytes (CTL). Here, we study the impact of three HDACis in clinical development on T-cell effector functions. We report two modes of HDACi-induced functional impairment: i) the rapid suppression of cytokine production from viable T-cells induced by all three HDACis ii) the selective death of activated T-cells occurring at later time-points following transient exposures to romidepsin or, to a lesser extent, panobinostat. As a net result of these factors, HDACis impaired CTL-mediated IFN-γ production, as well as the elimination of HIV-infected or peptide-pulsed target cells, both in liquid culture and in collagen matrices. Romidepsin exerted greater inhibition of antiviral function than SAHA or panobinostat over the dose ranges tested. These data suggest that treatment with HDACis to mobilize the latent reservoir could have unintended negative impacts on the effector functions of CTL. This could influence the effectiveness of HDACi-based eradication strategies, by impairing elimination of infected cells, and is a critical consideration for trials where therapeutic interruptions are being contemplated, given the importance of CTL in containing rebound viremia.

Topics: Cell Proliferation; Cell Survival; Cytotoxicity, Immunologic; Depsipeptides; Histone Deacetylase Inhibitors; HIV Infections; Humans; Hydroxamic Acids; Indoles; Panobinostat; T-Lymphocytes, Cytotoxic; Virus Replication

Histone deacetylase inhibitors (HDACi) can induce human immunodeficiency virus (HIV) transcription from the HIV long terminal repeat (LTR). However, ex vivo and in vivo responses to HDACi are variable and the activity of HDACi in cells other than T-cells have not been well characterised. Here, we developed a novel assay to determine the activity of HDACi on patient-derived HIV LTRs in different cell types. HIV LTRs from integrated virus were amplified using triple-nested Alu-PCR from total memory CD4+ T-cells (CD45RO+) isolated from HIV-infected patients prior to and following suppressive antiretroviral therapy. NL4-3 or patient-derived HIV LTRs were cloned into the chromatin forming episomal vector pCEP4, and the effect of HDACi investigated in the astrocyte and epithelial cell lines SVG and HeLa, respectively. There were no significant differences in the sequence of the HIV LTRs isolated from CD4+ T-cells prior to and after 18 months of combination antiretroviral therapy (cART). We found that in both cell lines, the HDACi panobinostat, trichostatin A, vorinostat and entinostat activated patient-derived HIV LTRs to similar levels seen with NL4-3 and all patient derived isolates had similar sensitivity to maximum HDACi stimulation. We observed a marked difference in the maximum fold induction of luciferase by HDACi in HeLa and SVG, suggesting that the effect of HDACi may be influenced by the cellular environment. Finally, we observed significant synergy in activation of the LTR with vorinostat and the viral protein Tat. Together, our results suggest that the LTR sequence of integrated virus is not a major determinant of a functional response to an HDACi.

Topics: Adult; Aged; Anti-HIV Agents; Benzamides; Cell Line; HeLa Cells; Histone Deacetylase Inhibitors; HIV Infections; HIV Long Terminal Repeat; Humans; Hydroxamic Acids; Indoles; Observational Studies as Topic; Panobinostat; Phylogeny; Pyridines; T-Lymphocytes; tat Gene Products, Human Immunodeficiency Virus; Vorinostat