Expression of PD-1 ligands by tumors and interaction with PD-1-expressing T cells in the tumor microenvironment can result in tolerance. Therapies targeting this coinhibitory axis have proven ...clinically successful in the treatment of metastatic melanoma, non-small cell lung cancer, and other malignancies. Therapeutic agents targeting the epigenetic regulatory family of histone deacetylases (HDAC) have shown clinical success in the treatment of some hematologic malignancies. Beyond direct tumor cell cytotoxicity, HDAC inhibitors have also been shown to alter the immunogenicity and enhance antitumor immune responses. Here, we show that class I HDAC inhibitors upregulated the expression of PD-L1 and, to a lesser degree, PD-L2 in melanomas. Evaluation of human and murine cell lines and patient tumors treated with a variety of HDAC inhibitors in vitro displayed upregulation of these ligands. This upregulation was robust and durable, with enhanced expression lasting past 96 hours. These results were validated in vivo in a B16F10 syngeneic murine model. Mechanistically, HDAC inhibitor treatment resulted in rapid upregulation of histone acetylation of the PD-L1 gene leading to enhanced and durable gene expression. The efficacy of combining HDAC inhibition with PD-1 blockade for treatment of melanoma was also explored in a murine B16F10 model. Mice receiving combination therapy had a slower tumor progression and increased survival compared with control and single-agent treatments. These results highlight the ability of epigenetic modifiers to augment immunotherapies, providing a rationale for combining HDAC inhibitors with PD-1 blockade.
Expression of HDAC11 may be involved in myeloid cell biology.
Epigenetic changes in chromatin structure have been recently associated with the deregulated expression of critical genes in normal and ...malignant processes. HDAC11, the newest member of the HDAC family of enzymes, functions as a negative regulator of IL‐10 expression in APCs, as previously described by our lab. However, at the present time, its role in other hematopoietic cells, specifically in neutrophils, has not been fully explored. In this report, for the first time, we present a novel physiologic role for HDAC11 as a multifaceted regulator of neutrophils. Thus far, we have been able to demonstrate a lineage‐restricted overexpression of HDAC11 in neutrophils and committed neutrophil precursors (promyelocytes). Additionally, we show that HDAC11 appears to associate with the transcription machinery, possibly regulating the expression of inflammatory and migratory genes in neutrophils. Given the prevalence of neutrophils in the peripheral circulation and their central role in the first line of defense, our results highlight a unique and novel role for HDAC11. With the consideration of the emergence of new, selective HDAC11 inhibitors, we believe that our findings will have significant implications in a wide range of diseases spanning malignancies, autoimmunity, and inflammation.
Checkpoint inhibitor therapy has led to major treatment advances for several cancers including non-small cell lung cancer (NSCLC). Despite this, a significant percentage of patients do not respond or ...develop resistance. Potential mechanisms of resistance include lack of expression of programmed death ligand 1 (PD-L1), decreased capacity to present tumor antigens, and the presence of an immunosuppressive tumor microenvironment. Mocetinostat is a spectrum-selective inhibitor of class I/IV histone deacetylases (HDACs), a family of proteins implicated in epigenetic silencing of immune regulatory genes in tumor and immune cells. Mocetinostat upregulated
PD
-
L1
and antigen presentation genes including class I and II human leukocyte antigen (HLA) family members in a panel of NSCLC cell lines in vitro. Mocetinostat target gene promoters were occupied by a class I HDAC and exhibited increased active histone marks after mocetinostat treatment. Mocetinostat synergized with interferon γ (IFN-γ) in regulating class II transactivator (
CIITA
), a master regulator of class II HLA gene expression. In a syngeneic tumor model, mocetinostat decreased intratumoral T-regulatory cells (Tregs) and potentially myeloid-derived suppressor cell (MDSC) populations and increased intratumoral CD8+ populations. In ex vivo assays, patient-derived, mocetinostat-treated Tregs also showed significant down regulation of FOXP3 and HELIOS. The combination of mocetinostat and a murine PD-L1 antibody antagonist demonstrated increased anti-tumor activity compared to either therapy alone in two syngeneic tumor models. Together, these data provide evidence that mocetinostat modulates immune-related genes in tumor cells as well as immune cell types in the tumor microenvironment and enhances checkpoint inhibitor therapy.
Histone acetylation and the families of enzymes responsible for controlling these epigenetic marks have been implicated in regulating T-cell maturation and phenotype. Here, we demonstrate a ...previously undefined role of histone deacetylase 11 (HDAC11) in regulating T-cell effector functions. Using EGFP-HDAC11 transgenic reporter mice, we found that HDAC11 expression was lower in effector relative to naive and central memory T-cell populations, and activation of resting T cells resulted in its decreased expression. Experiments using HDAC11 knockout (KO) mice revealed that T cells from these mice displayed enhanced proliferation, proinflammatory cytokine production, and effector molecule expression. In addition, HDAC11KO T cells had increased expression of Eomesodermin (Eomes) and TBX21 (Tbet), transcription factors previously shown to regulate inflammatory cytokine and effector molecule production. Conversely, overexpression of HDAC11 resulted in decreased expression of these genes. Chromatin immunoprecipitation showed the presence of HDAC11 at the Eomes and Tbet gene promoters in resting T cells, where it rapidly disassociated following T-cell activation. In vivo, HDAC11KO T cells were refractory to tolerance induction. HDAC11KO T cells also mediated accelerated onset of acute graft-versus-host disease (GVHD) in a murine model, characterized by increased proliferation of T cells and expression of interferon-γ, tumor necrosis factor, and EOMES. In addition, adoptive transfer of HDAC11KO T cells resulted in significantly reduced tumor burden in a murine B-cell lymphoma model. Taken together, these data demonstrate a previously unknown role of HDAC11 as a negative epigenetic regulator of T-cell effector phenotype and function.
•T cells from HDAC11KO mice have increased effector functions and mediate more rapid and potent GVHD.•HDAC11 associates with the Eomes and Tbet gene promoter regions in resting cells and disassociates upon activation.
Myeloid-derived suppressor cells (MDSCs), a heterogeneous population of cells capable of suppressing anti-tumor T cell function in the tumor microenvironment, represent an imposing obstacle in the ...development of cancer immunotherapeutics. Thus, identifying elements essential to the development and perpetuation of these cells will undoubtedly improve our ability to circumvent their suppressive impact. HDAC11 has emerged as a key regulator of IL-10 gene expression in myeloid cells, suggesting that this may represent an important targetable axis through which to dampen MDSC formation. Using a murine transgenic reporter model system where eGFP expression is controlled by the HDAC11 promoter (Tg-HDAC11-eGFP), we provide evidence that HDAC11 appears to function as a negative regulator of MDSC expansion/function in vivo. MDSCs isolated from EL4 tumor-bearing Tg-HDAC11-eGFP display high expression of eGFP, indicative of HDAC11 transcriptional activation at steady state. In striking contrast, immature myeloid cells in tumor-bearing mice display a diminished eGFP expression, implying that the transition of IMC to MDSC's require a decrease in the expression of HDAC11, where we postulate that it acts as a gate-keeper of myeloid differentiation. Indeed, tumor-bearing HDAC11-knockout mice (HDAC11-KO) demonstrate a more suppressive MDSC population as compared to wild-type (WT) tumor-bearing control. Notably, the HDAC11-KO tumor-bearing mice exhibit enhanced tumor growth kinetics when compare to the WT control mice. Thus, through a better understanding of this previously unknown role of HDAC11 in MDSC expansion and function, rational development of targeted epigenetic modifiers may allow us to thwart a powerful barrier to efficacious immunotherapies.
Abstract
PD-1 blockade has remarkable response rates in the treatment of melanoma; however, many patients fail to respond, and biomarkers and mechanisms of response remain unknown. We investigated ...the roles of Tregs, a population of immunosuppressive T-cells, in patient response to nivolumab. Tregs had a decrease in suppressive function in patients with positive outcomes (p=0.03), but not in patients with negative outcomes. Patients with no evidence of disease (NED) displayed increased percentages of Tregs post-nivolumab (p=0.04), but relapsing patients did not. RNA-seq analysis revealed genes significantly changed after treatment were distinct between Tcons and Tregs (~13% overlap) and between NED and relapsing patient Tregs (~2% overlap). Pathway analysis showed an increase in proliferation associated pathways in NED patient Tregs, but not relapsing patients. We found increased phosphoSTAT3 (pSTAT3) expression in Tregs from patients with positive outcomes (p=0.01), but not in patients with negative outcomes. Mechanistically, in vitro culturing of T-cells with αPD-1 resulted in increases in pSTAT3 expression (p=0.03) and increased percentages of Tregs (p=0.001). Culturing with αPD-1 also enhanced production of IL-10 (p=0.02), and the addition of a STAT3 inhibitor reduced the increases in IL-10 levels (p=0.01) and Treg percentages (p=0.01). The addition of an IL-10 neutralizing antibody also reduced the increased Tregs resulting from αPD-1 (p=0.01). These results support a model in which PD-1 blockade increases pSTAT3 expression leading to enhanced IL-10 production and Treg percentages, suggesting that pSTAT3 induction and reduced suppressive function are biomarkers of melanoma patient response to nivolumab.
ABSTRACT Objective: To verify the possible relationship between serum uric acid concentrations and insulin resistance in adolescents. Methods: This is a cross-sectional study with 74 participants ...from a public school in São Luís, Maranhão, aged between 10 and 19 years. The study was approved by the Ethics and Research Committee of the University Hospital of the Universidade Federal do Maranhão (UFMA) under report 2,673,791. Anthropometric measurements, blood pressure and blood collection were performed. The participants were divided into two groups: group 1 (with hyperuricemia) and group 2 (without hyperuricemia). Data analysis was performed by means of the Stata program. Results: Anthropometric measurements, such as body mass index and waist circumference, had statistical significance (p < 0.05) among groups with hyperuricemia and without hyperuricemia, as well as the percentage of body fat (p = 0.0423) and systolic and diastolic blood pressure (p = 0.0235). Biochemical parameters for total cholesterol (p = 0.0172), triglycerides (p = 0.0268), glucose (p = 0.0284) and TyG index (p = 0.0416) had statistical significance in the hyperuricemia group when compared to the group without hyperuricemia. Conclusion: According to the obtained results, the participants with insulin resistance calculated by the TyG index presented high serum acid levels, demonstrating a statistically significant correlation.
PDF
