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Edward Seto - One of the best experts on this subject based on the ideXlab platform.
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hdac11 regulates expression of c ebpβ and immunosuppressive molecules in myeloid derived suppressor cells
Journal of Leukocyte Biology, 2021Co-Authors: Jie Chen, Edward Seto, Eva Sahakian, John Powers, Fengdong Cheng, Jianguo Tao, Zi Wang, Javier Pinillaibarz, Eduardo M. SotomayorAbstract:Myeloid-derived suppressor cells (MDSCs) constitute a heterogeneous population of immature myeloid cells derived from bone marrow and negatively regulate both innate and adaptive immunity in the tumor microenvironment. Previously we have demonstrated that MDSCs lacking histone deacetylase 11 (HDAC11) displayed an increased suppressive activity against CD8+ T-cells. However, the mechanisms of HDAC11 that contribute to the suppressive function of MDSCs remain unclear. Here, we show that arginase activity and NO production is significantly higher in HDAC11 knockout MDSCs when compared with wild-type (WT) controls. In the absence of HDAC11, elevated arginase level and enzymatic activity were observed preferentially in the tumor-infiltrated granulocytic MDSCs, whereas iNOS expression and NO production were increased in the tumor-infiltrated monocytic MDSCs. Of note and for the first time, we demonstrated an association between the elevated expression of immunosuppressive molecules with up-regulation of the transcription factor C/EBPβ in MDSCs lacking HDAC11. Interestingly, the highest expression of C/EBPβ was observed among CD11b+ Gr-1+ MDSCs isolated from tumor-bearing mice. The additional demonstration that HDAC11 is recruited to the promoter region of C/EBPβ in WT MDSCs suggests a novel molecular mechanism by which HDAC11 influence the expression of immunosuppressive molecules in MDSCs through regulation of C/EBPβ gene expression.
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HDAC10 Regulates Cancer Stem-like Cell Properties in KRAS-driven Lung Adenocarcinoma
Cancer research, 2020Co-Authors: Xiangyang Zhang, Shaoqi Zhu, Eden A. Dejene, Weiqun Peng, Antonia R Sepulveda, Edward SetoAbstract:Activation of oncogenic KRAS is the most common driving event in lung adenocarcinoma development. Despite the existing rationale for targeting activated KRAS and its downstream effectors, the failure of clinical trials to date indicates that the mechanism of KRAS-driven malignancy remains poorly understood. Here we report that histone deacetylase 10 (HDAC10) might function as a putative tumor suppressor in mice carrying a spontaneously activated oncogenic Kras allele. HDAC10 deletion accelerated KRAS-driven early-onset lung adenocarcinomas, increased macrophage infiltration in the tumor microenvironment, and shortened survival time in mice. Highly tumorigenic and stem-like lung adenocarcinoma cells were increased in HDAC10-deleted tumors compared with HDAC10 wild-type tumors. HDAC10 regulated the stem-like properties of KRAS-expressing tumor cells by targeting SOX9. Expression of SOX9 was significantly increased in HDAC10-deleted tumor cells and depletion of SOX9 in HDAC10 knockout (KO) lung adenocarcinoma cells inhibited growth of tumorspheres. The genes associated with TGFβ pathway were enriched in HDAC10 KO tumor cells, and activation of TGFβ signaling contributed to SOX9 induction in HDAC10 KO lung adenocarcinoma cells. Overall, our study evaluates the functions and mechanisms of action of HDAC10 in lung carcinogenesis that will inform the rationale for targeting its related regulatory signaling as an anticancer strategy. SIGNIFICANCE: These findings linking HDAC10 and lung tumorigenesis identify potential novel strategies for targeting HDAC10 as a treatment for lung cancer.
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hdac11 regulates type i interferon signaling through defatty acylation of shmt2
Proceedings of the National Academy of Sciences of the United States of America, 2019Co-Authors: Edward Seto, Lei Sun, Hening Lin, Ji Cao, Pornpun Aramsangtienchai, Nicole A Spiegelman, Xiaoyu Zhang, Weishan HuangAbstract:The smallest histone deacetylase (HDAC) and the only class IV HDAC member, HDAC11, is reported to regulate immune activation and tumorigenesis, yet its biochemical function is largely unknown. Here we identify HDAC11 as an efficient lysine defatty-acylase that is >10,000-fold more efficient than its deacetylase activity. Through proteomics studies, we hypothesized and later biochemically validated SHMT2 as a defatty-acylation substrate of HDAC11. HDAC11-catalyzed defatty-acylation did not affect the enzymatic activity of SHMT2. Instead, it affects the ability of SHMT2 to regulate type I IFN receptor ubiquitination and cell surface level. Correspondingly, HDAC11 depletion increased type I IFN signaling in both cell culture and mice. This study not only demonstrates that HDAC11 has an activity that is much more efficient than the corresponding deacetylase activity, but also expands the physiological functions of HDAC11 and protein lysine fatty acylation, which opens up opportunities to develop HDAC11-specific inhibitors as therapeutics to modulate immune responses.
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programming and regulation of metabolic homeostasis by hdac11
EBioMedicine, 2018Co-Authors: Lei Sun, Elphine Telles, Caralina Marin De Evsikova, Ka Bian, Alexandra Achille, Huadong Pei, Edward SetoAbstract:Abstract Histone deacetylases (HDACs) are enzymes that regulate protein functions by catalyzing the removal of acetyl and acyl groups from lysine residues. They play pivotal roles in governing cell behaviors and are indispensable in numerous biological processes. HDAC11, the last identified and sole member of class IV HDACs, was reported over a decade ago. However, its physiological function remains poorly understood. Here, we report that HDAC11 knockout mice are resistant to high-fat diet-induced obesity and metabolic syndrome, suggesting that HDAC11 functions as a crucial metabolic regulator. Depletion of HDAC11 significantly enhanced insulin sensitivity and glucose tolerance, attenuated hypercholesterolemia, and decreased hepatosteatosis and liver damage. Mechanistically, HDAC11 deficiency boosts energy expenditure through promoting thermogenic capacity, which attributes to the elevation of uncoupling protein 1 (UCP1) expression and activity in brown adipose tissue. Moreover, loss of HDAC11 activates the adiponectin-AdipoR-AMPK pathway in the liver, which may contribute to a reversal in hepatosteatosis. Overall, our findings distinguish HDAC11 as a novel regulator of obesity, with potentially important implications for obesity-related disease treatment.
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HDAC11 Deficiency Prevents High-Fat Diet-Induced Obesity and Metabolic Syndrome
2018Co-Authors: Lei Sun, Elphine Telles, Caralina Marin De Evsikova, Ka Bian, Alexandra Achille, Edward SetoAbstract:Obesity and its associated metabolic syndromes are the consequence of susceptible genes and obesogenic environments. We report here that histone deacetylase 11 (HDAC11) plays a critical role in the development of obesity and in metabolic homeostasis. HDAC11 knockout mice display resistance to high-fat diet-induced obesity and associated syndromes by enhancing glucose tolerance and insulin sensitivity, attenuating hypercholesterolemia and hyperinsulinemia, and blocking hepatosteatosis and liver damage. Mechanistically, HDAC11 deficiency boosts energy expenditure through promoting thermogenic capacity, which attributes to the elevation of uncoupling protein 1 (UCP1) expression and activity in brown adipose tissue. Moreover, loss of HDAC11 stimulates mitochondrial oxidation, elevates plasma adiponectin, and activates the adiponectin-AdipoR-AMPK pathway in the liver, which may contribute to a reversal in hepatosteatosis. These findings establish HDAC11 as a key regulator of metabolism and indicate that HDAC11 inhibitors may hold promise for treating overweight and obesity related diseases.
Alejandro Villagra - One of the best experts on this subject based on the ideXlab platform.
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a novel role for histone deacetylase 10 HDAC10 in the regulation of pd l1 expression and immune tolerance mediated by antigen presenting cells apcs
Blood, 2017Co-Authors: Michael Wang, Edward Seto, Jie Chen, Fengdong Cheng, Alejandro Villagra, Mitchell R Smith, Eduardo SotomayorAbstract:Abstract Antigen-presenting cells (APCs) play a central role in determining T-cell activation versus T-cell anergy in the context of tumor growth. The inflammatory status of APCs at the time of tumor antigen presentation has been proposed as explanation for the induction of such divergent T-cell outcomes. This overall inflammatory status of APCs can be regulated epigenetically. HDAC10 is a member of the class IIb family of HDACs that represses gene transcription independent of its deacetylase activity when tethered to a promoter. It is normally expressed in liver, kidney, pancreas and spleen and its overexpression has been shown to accelerate cancer development. While we previously demonstrated a role for HDAC6, the other member of the class IIb family, in control of APC inflammatory vs tolerogenic status (Cheng F et al, J Immunol 2014), little is known about the role (if any) of HDAC10 in regulating APC's function. Here we show for the first time that knockdown of HDAC10 in APCs, using shRNA specific for murine HDAC10 or non-target control (NT), resulted in the induction of inflammatory APCs displaying an 20-30% increased expression of MHC class II molecules and abrogation of PD-L1 gene transcription (4 fold decreased) and expression as compared to controls. To further confirm these results in vivo, HDAC10 knock out (KO) mice were used. These HDAC10 KO mice, as compared to wild type (WT) mice, reveal no gross macroscopic abnormalities in any lymphoid organs. Macrophages isolated from HDAC10 KO mice demonstrated increased expression of MHC II molecules and decreased expression of PD-L1, analogous to the shRNA data. Furthermore, in vitro co-culture of these macrophages with antigen-specific CD4+ T cells lead to effective priming of naive CD4+ T-cells and restoration of the responsiveness of tolerant T-cells, as determined by their 3 fold increased production of IL-2 and IFN-g in response to cognate antigen. This demonstrates that APCs lacking HDAC10 are more immunogenic than control cells. Finally, to assess the role of HDAC10 in tumor immunity, we challenged HDAC10KO mice as well as WT control with murine mantle cell lymphoma (MCL) cells (FC-muMCL1 cells) given s.c. and measured tumor growth. A significant delay in MCL growth was observed in HDAC10KO mice as compared to WT controls (p In summary, our studies have unveiled previously unknown immunoregulatory properties of HDAC10. In particular, its regulatory effects upon the expression of the tolerogenic molecule PD-L1, opens new frontiers for the understanding of PD-L1 regulation and points to disruption of the HDAC10/PD-L1 axis as a novel epigenetic target for cancer immunotherapy. Disclosures Smith: Gilead: Research Funding; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Kite Pharma: Research Funding; Morphosys: Consultancy; Genentech: Membership on an entity's Board of Directors or advisory committees.
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Histone Deacetylase 11 (HDAC11) Interaction with Ikaros Represent a Novel Mechanism of Regulation of Essential Transcriptional Factors in CD4+ T Cells
Blood, 2016Co-Authors: Jie Chen, Edward Seto, Fengdong Cheng, David M Woods, Alejandro Villagra, Eduardo M. SotomayorAbstract:Histone deacetylase 11 (HDAC11), the most recently identified histone deacetylase, is the sole member of class IV HDACs [1]. Since its discovery, no biological function was assigned to this HDAC until we demonstrated its central role in negatively regulating IL-10 production in antigen presenting cells (APCs) [2]. More recently, we have found that disruption of HDAC11 in T cells is associated with an enhanced pro-inflammatory cytokine profile and effector molecule production. Furthermore, T-cells lacking HDAC11 were less susceptible to regulatory T-cell (Treg) suppression in vitro, were refractory to tolerance induction in vivo and displayed enhanced allo-reactivity and anti-tumor responses in murine models. Of note, T-cells lacking HDAC11 expressed higher levels of the transcription factors Eomes and Tbet. Conversely, overexpression of HDAC11 in T-cells decreased the expression of both transcription factors. The molecular mechanism(s) by which HDAC11 regulates the expression of these transcription factors have remained unknown. By using chromatin immunoprecipitation (ChIP) assay we found that in resting T-cells HDAC11 is present at the Eomes and Tbet gene promoters where it maintains histone deacetylation, a compacted chromatin and gene repression. Following T-cell stimulation, HDAC11 was largely absent from both promoters, which resulted in increased histone 3 (H3) acetylation and gene transcriptional activity. These findings were confirmed in T-cells isolated from HDAC11 knock out (KO) mice which also displayed an increase in H3 acetylation at the Tbet and Eomes gene promoter regions. Conversely, H3 acetylation was decreased in both gene promoters in T-cells overexpressing HDAC11 as compared to empty-vector transfected cells. Given that HDACs do not bind to DNA, we asked next which transcription factor(s) HDAC11 might be associated with, in order to regulate Tbet and Eomes gene transcriptional activity. In prior studies we have found that HDAC11 form a molecular complex with another member of the HDAC family, HDAC6, which physically interacts with the transcription factor, STAT3 in both the cytoplasmic and nuclear compartments. However, in T-cells no direct interaction of HDAC11 with STAT3 was detected in either compartment. In contrast, we found for the first time that HDAC11 physically associates with Ikaros (Ikzf1), a member of the Ikaros zinc finger transcription factor family that has been previously implicated in the regulation of T-bet gene expression and IFN-g production in T-cells [3-5]. The protein complex HDAC11-Ikaros was mainly detected in the nuclear compartment and both proteins were present at the T-bet gene promoter. Collectively, these results point to the HDAC11-Ikaros complex as a novel epigenetic mechanism of regulation of Tbet and Eomes, transcription factors that are essential for T cell development and function. Disclosures Woods:BMS: Other: Stock; HDAC11: Patents & Royalties: Patent for targeting HDAC11; Lion Biotech: Other: Stock.
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Expression and Function of Histone Deacetylase 10 (HDAC10) in B Cell Malignancies
Methods in molecular biology (Clifton N.J.), 2016Co-Authors: John Powers, Maritza Lienlaf, Patricio Perez-villarroel, Tessa Knox, Alejandro VillagraAbstract:Histone deacetylase 10 (HDAC10) belongs to the class IIb HDAC family and its biological role remains mostly unidentified. A decreased HDAC10 expression has been reported in patients with aggressive solid tumors (Osada et al. Int J Cancer 112: 26-32, 2004; Jin et al. Int J Clin Exp Pathol 7: 5872-5879, 2014), suggesting that loss of HDAC10 expression might confer a survival advantage to malignant cells. Consequently, results from our lab suggests that overexpression of HDAC10 in aggressive mantle cell lymphoma (MCL) and chronic lymphocytic leukemia (CLL) Z138c and MEC1 cells, respectively, resulted in a rapid induction of cell death in vitro with only 5 % of cells being alive at 48 h, cell cycle arrest, and up-regulation of co-stimulatory molecules. Here we present several standard methods to study the function of HDAC10 in B cell malignancies.
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A Novel Role for Histone Deacetylase 11 (HDAC11) in B Cell Lymphopoiesis and Plasma Cell Survival in Multiple Myeloma
Blood, 2014Co-Authors: Jason Brayer, Eva Sahakian, John Powers, Allison Distler, Mark B. Meads, Susan Deng, Melissa Alsina, Taiga Nishihori, Rachid Baz, Alejandro VillagraAbstract:While multiple myeloma (MM) remains incurable presently, expanded therapeutic options over the past decade have improved patient survival markedly. Proteasome inhibitors have redefined the treatment paradigm for myeloma, often serving as the backbone of front-line treatment. Histone deacetylase (HDAC) inhibitors (HDI), although only marginally active as single agent therapy in hematological malignancies, have demonstrated an ability to salvage bortezomib responsiveness in refractory patients, prompting heightened interest in this class of targeted therapeutics in myeloma. HDAC’s represent a family of enzymes, currently with 11 known members in the classical HDAC family, and subdivided into 4 sub-classes. HDAC11 is currently the only member of the sub-class IV and, as the newest member of the HDAC family, its impact on B cell lymphopoiesis and myeloma development is only starting to be unveiled. Intriguingly, we show that mice with germ-line silencing of HDAC11 (HDAC11KO mice) exhibit a 50% decrease in plasma cells in both the bone marrow and peripheral blood plasma cell compartments relative to wild-type mice. Consistent with this, Tg-HDAC11-eGFP mice, a transgenic strain engineered to express GFP under control of the HDAC11 promoter (Heinz, N Nat. Rev. Neuroscience 2001) reveals that HDAC11 expression is increased in the plasma cell population and to a lesser extent B1 B cells, as compared to earlier lineage stages. Similar observations based on measurements of HDAC11 mRNA were seen in normal human plasma cells. Significant increases in HDAC11 mRNA expression were observed in 7 of 11 primary human multiple myeloma samples and 11 of 12 human myeloma cell lines as compared to normal plasma cells, further emphasizing the potential relevance of HDAC11 to the underlying pathologic processes driving myeloma development and/or survival. Targeted silencing of HDAC11 in RPMI-8226 cells lines using siRNA results in a modest decrease in cell viability as measured by Annexin/PI staining and detection of activated caspase-3. Quisinostat, a second generation pan-HDI, has previously demonstrated activity against human myeloma cell lines in vitro (Stuhmer, Brit J Haematol, 2010), and suppressed bone destruction in an in vivo murine myeloma model (Deleu, Cancer Res, 2009). We similarly observe dose-dependent survival impairment in 10 human myeloma cell lines when cultured in the presence of quisinostat, with EC50’s consistently in the 1-10nM range. Importantly, quisinostat acts synergistically with proteasome inhibitiors (bortezomib and carfilzomib) in RPMI-8226 cells; more importantly, the degree of synergism is amplified in the RPMI-6226-B25 bortezomib-resistant cell line. Although a clear mechanism of action remains to be elucidated, preliminary data suggests that RPMI-8226 cells exposed to quisinostat appear to exhibit a decrease nuclear, but not cytosolic HDAC11. Collectively, these data illustrate a previously unknown role for HDAC11 in plasma cell differentiation and survival. Increased HDAC11 expression seen in myeloma patient specimens and primary myeloma cell lines highlights the potential of HDAC11 as a therapeutic target. Furthermore, we show that quisinostat, a pan-HDI with selectivity towards HDAC11 at lower dosing, acts synergistically with proteasome inhibitors in vitro in proteasome inhibitor sensitive and resistant cell lines. Future work will focus on further elucidating the role of HDAC11 in myeloma survival and drug response, with particular emphasis on proteasome inhibitors. Disclosures No relevant conflicts of interest to declare.
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Abstract 5537: Histone deacetylase 11 (HDAC11) regulates B cell lymphopoiesis and potentiates plasma cell survival in multiple myeloma
Experimental and Molecular Therapeutics, 2014Co-Authors: Eva Sahakian, John Powers, Allison Distler, Jason Brayer, Mark B. Meads, Susan Deng, Melissa Alsina, Taiga Nishihori, Rachid Baz, Alejandro VillagraAbstract:Initially studied mainly for its role as a regulator of neural cell differentiation and development, expression of HDAC11 was once thought to be restricted exclusively to brain, kidney and testes. Hence, our recent discovery that HDAC11 acts as an important modulator of antigen presentation and T cell activation, downregulating IL-10 transcription via interactions with the IL-10 promoter at the chromatin level, exposes a previously unknown capacity and tissue specificity for this enzyme. Transgenic mice harboring an eGFP reporter construct driven by the HDAC11 promoter (Tg-HDAC11-eGFP) (Heinz, N Nat. Rev. Neuroscience 2001) clearly illustrate the dynamic changes in HDAC11 gene expression in hematopoietic cell lineages, additionally unveiling an important role for HDAC11 in B cell lymphopoiesis and plasma cell biology. While common lymphoid progenitors appear to be devoid of HDAC11 transcriptional activation as indicated by minimal detectable eGFP expression, eGFP intensity markedly increases in the B-1 stage of differentiation in the periphery. Interestingly, examination of both the bone marrow (BM) and peripheral blood (PB) plasma cell compartment demonstrates an increase in expression of eGFP/HDAC11 mRNA at the steady-state, and these results are consistent with HDAC11 expression measured in PB from healthy human subjects. Furthermore, mice globally deficient in HDAC11 expression (HDAC11KO mice) exhibit a 50% decrease in plasma cells in both the bone marrow and peripheral blood plasma cell compartments relative to wild-type mice. The concordance of HDAC11 expression and plasma cell differentiation leads us to hypothesize that HDAC11 may also be critical to malignant plasma cell survival. A comparison of normal bone marrow and malignant plasma cells isolated from multiple myeloma patient samples reveals a significantly higher level of HDAC11 expression associated with malignancy. Similar results are observed in 8 of 12 myeloma cell lines suggesting that HDAC11 expression may provide a distinct survival advantage to malignant plasma cells. Further stratification of patients into “newly diagnosed” and “proteasome inhibitor resistant” categories defines a positive correlation between HDAC11 expression and refractory disease. Treatment of the myeloma cell lines with Quisinostat, a second-generation HDAC inhibitor with enhanced selectivity for HDAC 1, 2, 4, 10 and 11 induces growth retardation at low nanomolar concentrations. Future studies will entail direct targeting of HDAC11 in myeloma cell lines and patient specimens to determine the contribution of HDAC11 to Quinsinostat activity. Taken together, we have unveiled a previously unknown role for HDAC11 in plasma cell differentiation and survival. The demonstration of HDAC11 overexpression in primary human myeloma cells provides a framework for therapeutics targeting this HDAC in multiple myeloma. Citation Format: Eva Sahakian, Jason Brayer, John Powers, Mark Meads, Susan Deng, Allison Distler, Melissa Alsina, Taiga Nishihori, Rachid Baz, Alejandro Villagra, Javier Pinilla-Ibarz, Eduardo Sotomayor, Kenneth Shain. Histone deacetylase 11 (HDAC11) regulates B cell lymphopoiesis and potentiates plasma cell survival in multiple myeloma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5537. doi:10.1158/1538-7445.AM2014-5537
John Powers - One of the best experts on this subject based on the ideXlab platform.
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hdac11 regulates expression of c ebpβ and immunosuppressive molecules in myeloid derived suppressor cells
Journal of Leukocyte Biology, 2021Co-Authors: Jie Chen, Edward Seto, Eva Sahakian, John Powers, Fengdong Cheng, Jianguo Tao, Zi Wang, Javier Pinillaibarz, Eduardo M. SotomayorAbstract:Myeloid-derived suppressor cells (MDSCs) constitute a heterogeneous population of immature myeloid cells derived from bone marrow and negatively regulate both innate and adaptive immunity in the tumor microenvironment. Previously we have demonstrated that MDSCs lacking histone deacetylase 11 (HDAC11) displayed an increased suppressive activity against CD8+ T-cells. However, the mechanisms of HDAC11 that contribute to the suppressive function of MDSCs remain unclear. Here, we show that arginase activity and NO production is significantly higher in HDAC11 knockout MDSCs when compared with wild-type (WT) controls. In the absence of HDAC11, elevated arginase level and enzymatic activity were observed preferentially in the tumor-infiltrated granulocytic MDSCs, whereas iNOS expression and NO production were increased in the tumor-infiltrated monocytic MDSCs. Of note and for the first time, we demonstrated an association between the elevated expression of immunosuppressive molecules with up-regulation of the transcription factor C/EBPβ in MDSCs lacking HDAC11. Interestingly, the highest expression of C/EBPβ was observed among CD11b+ Gr-1+ MDSCs isolated from tumor-bearing mice. The additional demonstration that HDAC11 is recruited to the promoter region of C/EBPβ in WT MDSCs suggests a novel molecular mechanism by which HDAC11 influence the expression of immunosuppressive molecules in MDSCs through regulation of C/EBPβ gene expression.
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functional analysis of hdac11 in plasma cell development and multiple myeloma survival
Blood, 2018Co-Authors: A G M Mostofa, Eva Sahakian, John Powers, Allison Distler, Mark B. Meads, Melissa Alsina, Taiga Nishihori, Rachid Baz, Tuan Nguyen, Javier Pinilla IbarzAbstract:Abstract Background: Histone deacetylases (HDACs) are potential novel therapeutic targets for multiple myeloma (MM) treatment. A pan-HDAC inhibitor (HDI) panobinostat was approved by the FDA in 2015 to treat relapsed/refractory MM patients, and several other HDIs are currently in different phases of clinical trials. However, unfavorable side-effects of the non-selective HDIs necessitate further dissection of the roles of individual HDAC isoforms to best target plasma cell malignancies with minimal toxicity. HDAC11 was recently found to regulate function in key immune cell populations including regulatory T cells, effector T cells, neutrophils, and myeloid-derived suppressor cells (MDSC). Though HDAC11 expression is confirmed in B cells and plasma cells, its functions in these cells remain largely unknown. In this study, we attempted a functional analysis of HDAC11 in plasma cell development along with its pro-tumorigenic function in MM cells. Methods: Mouse models, including a transgenic mouse strain expressing eGFP under the regulation of the HDAC11 promoter (Tg-HDAC11-eGFP), and also an HDA11-deficient mouse (B6.HDAC11-/-) were studied to establish the importance of HDAC11 in plasma cell biology. Pharmacologic inhibition of HDAC11 in MM cell lines was accomplished by using elevenostat, a new HDAC11-selective inhibitor in comparison with pan-inhibitors quisinostat and panobinostat. Impact on viability in human-derived MM cell lines was assessed using the CCK-8 assay, while induction of cell death was measured via detection of activated Caspase-3 and annexin/propidium iodide staining by flow cytometry. Synergy studies were performed by following the Chou-Talalay method for drug combinations. Post-translational modifications and subcellular localization changes induced by HDIs exposure were assessed by western blotting of fractionated cell lysates, while immunoprecipitation and proximity ligation assays (in situ PLA) were used to identify a binding partner for HDAC11. Results: Studies in Tg-HDAC11-eGFP mice reveal that HDAC11 expression in B cell lymphopoiesis is minimally detectable prior to B cell activation but demonstrates strong induction upon maturation into a plasma cell. Consistent with this, plasma cell development is markedly impaired in the absence of HDAC11. The HDAC11-selective inhibitor elevenostat showed significant cytotoxic potential in different MM cell lines that express moderate to high level of HDAC11, with IC50 values ranging 0.6-2.0 µM. Consistently, MM cell lines expressing null/very low level of HDAC11 were insensitive to elevenostat. Moreover, combining elevenostat with proteasome inhibitors bortezomib (BTZ) and carfilzomib resulted in significant synergistic effects evident from combination index (CI) and dose-reduction index (DRI) values measured by CompuSyn software. Elevenostat was also able to re-sensitize BTZ-resistant sub-clones (e.g., RPMI-8226-B25, KAS-6-V10R, and ANBL6-V10R) to BTZ and exhibited superior synergistic effects. Furthermore, elevenostat-treated cells showed a time-dependent alteration in the subcellular localization of HDAC11. HDAC11 gradually disappeared from the nuclear fractions with simultaneous upregulation in cytoplasmic fractions; similar observations were made from pan HDIs (quisinostat and panobinostat) treatment. However, unlike pan HDIs, the elevenostat treatment caused global downregulation of HDAC11 in some MM cell lines at the later time points (72 or 96 hrs), suggesting differential effects of various HDIs. Inhibition of HDAC11 also caused downstream suppression of several pro-tumorigenic factors of MM cells including IRF4 and c-Myc. Additionally, a novel interaction between HDAC11 and IRF4, an essential regulator of PC differentiation and MM survival, was identified by using PLA. HDAC11 dynamically interacts with IRF4 which can be induced by LPS stimulation and inhibited by HDIs, indicating the involvement of HDAC11 in the IRF4-mediated regulatory circuit. Conclusions: We observe that targeted inhibition of HDAC11 can impair MM cell survival and overcome acquired resistance to proteasome inhibitors. Furthermore, we identify IRF4 as a nuclear binding partner of HDAC11 and propose this interaction as a candidate mechanism regulating PC maturation and survival. Disclosures No relevant conflicts of interest to declare.
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hdac11 is a candidate therapeutic target in multiple myeloma
Blood, 2017Co-Authors: Jason Brayer, Eva Sahakian, John Powers, Allison Distler, Mark B. Meads, Melissa Alsina, Taiga Nishihori, Rachid Baz, Tuan Nguyen, Javier PinillaibarzAbstract:Background: Histone deacetylase (HDAC) inhibitors (HDI), although only marginally active as single agent therapy in multiple myeloma (MM), demonstrate an ability to salvage proteasome inhibitors (PIs) and immunomodulatory drugs (IMiDs) responsiveness in refractory patients, thus raising interest in this class of targeted therapeutics. Selective inhibition of particular HDAC isoforms may further improve therapeutic efficacy. HDAC11, the newest member of the HDAC family, is expressed in a progressive manner during B cell development with greatest expression in mature plasma cells (PC). Methods: B cell lymphopoiesis was evaluated using Tg-HDAC11-eGFP mice expressing eGFP regulated by the HDAC11 promoter and congenic mouse strains deficient in HDAC11 expression globally (B6.HDAC11-/-) or targeted to the B cell lineage (CD19Cre.HDAC11-/-). In vitro assays were completed using established human myeloma cell lines that include RPMI-8226, RPMI-8226-B25, OPM2, H929, KMS11, KMS28, KAS6, KAS6R10R, MM1.S, and MM1R10R (kind gift from Dr. Orlowski). Inhibition of HDAC11 in MM cell lines was accomplished by both molecular and pharmacologic approaches. Viability was measured according to activated caspase-3 and Annexin/PI staining by flow cytometry, and by CCK-8 viability assay. Subcellular localization changes induced by HDI exposure were assessed by Western Blot of fractionated cell lysates, while immunoprecipitation and confocal microscopy, using both immunofluorescence and proximity ligation assay techniques, were used to identify IRF4 as a novel nuclear binding partner for HDAC11. Results: Profound eGFP increases in PC of Tg-HDAC11-eGFP mice suggest HDAC11 influences late stage B cell development. Consistent with this, HDAC11 deficiency results in dramatically reduced PC in the bone marrow and periphery. PC depletion in CD19Cre.HDAC11-/- mice, where HDAC11 ablation is restricted to the B cell lineage, suggests activity inherent in B cells rather than via externally derived signals. Initial studies evaluating the effects of quisinostat, a second-generation HDI with increased selectivity that includes HDAC11, showed dose-dependent cytotoxicity versus 10 myeloma cell lines with EC50 measurements in the 1-10nM range. This activity was synergistic with BTZ and carfilzomib (CFZ) in RPMI-8226 cells and degree of synergism was amplified in the BTZ-resistant RPMI-8226-B25 cell line. Subsequent experiments using HDTK-010 (FORMA Therapeutics), an HDAC11-selective HDI, showed dose-dependent cytotoxicity in 21 MM cell lines (EC50 1-10mM). Targeted siRNA-mediated silencing of HDAC11 in RPMI-8226 cells yielded a reduction in cell viability, as measured by Annexin/PI staining and detection of activated caspase-3. An important interaction between HDAC11 and IRF4, an essential regulator of PC differentiation and MM survival, was first identified by immunoprecipitation assay in 8226 cells. This interaction has been confirmed by confocal microscopy using immunofluorescent co-localization and proximity ligation techniques in 8226, MM1.S, OPM2 and H929 cell lines as well as in CD138-enriched MM cells from patient marrow aspirates. Furthermore, this interaction is disrupted by exposure to quisinostat, panobinostat, and HDTK-010. The identification of IRF4 as a putative binding partner for HDAC11 unveils a potential mechanism by which HDAC11 may regulate MM cell survival. Conclusions:We show that MM cell survival can be impaired by targeted inhibition of HDAC11. Furthermore, we identify IRF4 as a nuclear binding partner for HDAC11 and propose this interaction as a candidate mechanism regulating PC maturation and MM cell survival. Disclosures Baz: Sanofi: Research Funding; BMS: Research Funding; merck: Research Funding; takeda: Research Funding; celgene: Honoraria, Research Funding; karyopharm: Research Funding. Pinilla-Ibarz: ARIAD: Consultancy, Honoraria; BMS: Honoraria, Speakers Bureau; Pfizer: Honoraria, Speakers Bureau.
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Expression and Function of Histone Deacetylase 10 (HDAC10) in B Cell Malignancies
Methods in molecular biology (Clifton N.J.), 2016Co-Authors: John Powers, Maritza Lienlaf, Patricio Perez-villarroel, Tessa Knox, Alejandro VillagraAbstract:Histone deacetylase 10 (HDAC10) belongs to the class IIb HDAC family and its biological role remains mostly unidentified. A decreased HDAC10 expression has been reported in patients with aggressive solid tumors (Osada et al. Int J Cancer 112: 26-32, 2004; Jin et al. Int J Clin Exp Pathol 7: 5872-5879, 2014), suggesting that loss of HDAC10 expression might confer a survival advantage to malignant cells. Consequently, results from our lab suggests that overexpression of HDAC10 in aggressive mantle cell lymphoma (MCL) and chronic lymphocytic leukemia (CLL) Z138c and MEC1 cells, respectively, resulted in a rapid induction of cell death in vitro with only 5 % of cells being alive at 48 h, cell cycle arrest, and up-regulation of co-stimulatory molecules. Here we present several standard methods to study the function of HDAC10 in B cell malignancies.
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histone deacetylase 11 a novel epigenetic regulator of myeloid derived suppressor cell expansion and function
Molecular Immunology, 2015Co-Authors: Eva Sahakian, John Powers, Jie Chen, Susan L Deng, Fengdong Cheng, Allison Distler, David M Woods, Jennifer Rockklotz, Andressa L Sodre, Je In YounAbstract: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.
X Liu - One of the best experts on this subject based on the ideXlab platform.
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HDAC10 is positively associated with pd l1 expression and poor prognosis in patients with nsclc
Frontiers in Oncology, 2020Co-Authors: X Liu, Yuxi Wang, Rong Zhang, Ting Jin, Qianwen Jin, Jiasu Zheng, Jiaqi Sun, Linxi Wang, Tianxu Liu, Yinxu ZhangAbstract:Currently, non-small cell lung carcinoma (NSCLC) is remaining a major worldwide health problem. Meanwhile, accumulating evidences indicate that Histone deacetylase (HDACs) activation could induce PD-L1 expression in various types of cancer, especially in myeloma and B-cell lymphomas. Therefore, we hypothesized that high-level expression of HDAC10 is associated with PD-L1 induction and poor prognosis in patients with NSCLC. Totally, 180 NSCLC patients receiving complete pulmonary resection and systematic lymph node dissection were enrolled from April 2004 to August 2009. The patients with integrated clinicopathological records were followed up. The expression level of HDAC10 and PD-L1 in tissue samples was determined by immunohistochemistry. We observed that HDAC10 expression in lung cancer tissue is significantly higher than that in corresponding para-cancer tissue. Moreover, HDAC10 expression positively correlated with the expression level of PD-L1 (r=0.213, P<0.05) in NSCLC patients. In the subgroup, multivariate analysis showed that the expression level of HDAC10 can be an independent prognostic factor and high-level expression of HDAC10 indicated a poor overall survival in pulmonary carcinoma (r=0.540, P<0.001). Our findings suggest that the expression level of HDAC10 is positively associated with PD-L1 expression and may predict outcome of patients with NSCLC.
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high level expression of HDAC10 is associated with pd l1 expression and poor prognosis in patients with non small cell lung cancer receiving pulmonectomy
Annals of Oncology, 2019Co-Authors: X LiuAbstract:Abstract Background Recent studies showed that stimulation of HDACs could induce PD-1 dynamic expression on DCs, macrophages, colonic stromal cells, and cancer cells. Surprisingly, it is little is known about the specific expression of important HDAC10 in NSCLC tissue. In this study, we evaluated the expression level of HDAC10 and the correlation of HDAC10 and PD-L1 in NSCLC tissues and analyzed the predicting role of HDAC10 in cancer cells on postoperative survival in NSCLC patients receiving pulmonary lobectomy. Methods A total of 180 NSCLC patients receiving complete pulmonary resection and systematic lymph node dissection between April 2004 and August 2009 were enrolled. All the patients had integrated clinicopathological records and follow-up data. HDAC10 and PD-L1 expression on NSCLC samples were determined by using immunohistochemistry. Results Our results showed that HDAC10 expression level in cancer tissue was significantly higher than that in para-cancer tissue. HDAC10 expression level was also positively correlated with the PD-L1 expression level (r = 0.213, P Conclusions To our knowledge, this is the first time to associate HDAC10 with lung cancer patients’ survival status and to explore correlation between HDAC10 and PD-L1 expression. Our findings indicated that HDAC10 could be a valuable predicting marker that might provide help for clinicians to design effective therapeutic modality against NSCLC. Treatment response might be especially prominent in patients overexpressing HDAC10 in cancer cells. Our study suggest clinical relevance for the immune effects of HDAC10 and provide a rationale for the clinical evaluation of PD-L1 blockade in combination with HDAC10 inhibition. Legal entity responsible for the study The First Affiliated Hospital of Jinzhou Medical University. Funding This study was supported by the CSCO-HANSOH PHARMA Science Foundation of China (number Y-HS2019-29). Disclosure The author has declared no conflicts of interest.
Eva Sahakian - One of the best experts on this subject based on the ideXlab platform.
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hdac11 regulates expression of c ebpβ and immunosuppressive molecules in myeloid derived suppressor cells
Journal of Leukocyte Biology, 2021Co-Authors: Jie Chen, Edward Seto, Eva Sahakian, John Powers, Fengdong Cheng, Jianguo Tao, Zi Wang, Javier Pinillaibarz, Eduardo M. SotomayorAbstract:Myeloid-derived suppressor cells (MDSCs) constitute a heterogeneous population of immature myeloid cells derived from bone marrow and negatively regulate both innate and adaptive immunity in the tumor microenvironment. Previously we have demonstrated that MDSCs lacking histone deacetylase 11 (HDAC11) displayed an increased suppressive activity against CD8+ T-cells. However, the mechanisms of HDAC11 that contribute to the suppressive function of MDSCs remain unclear. Here, we show that arginase activity and NO production is significantly higher in HDAC11 knockout MDSCs when compared with wild-type (WT) controls. In the absence of HDAC11, elevated arginase level and enzymatic activity were observed preferentially in the tumor-infiltrated granulocytic MDSCs, whereas iNOS expression and NO production were increased in the tumor-infiltrated monocytic MDSCs. Of note and for the first time, we demonstrated an association between the elevated expression of immunosuppressive molecules with up-regulation of the transcription factor C/EBPβ in MDSCs lacking HDAC11. Interestingly, the highest expression of C/EBPβ was observed among CD11b+ Gr-1+ MDSCs isolated from tumor-bearing mice. The additional demonstration that HDAC11 is recruited to the promoter region of C/EBPβ in WT MDSCs suggests a novel molecular mechanism by which HDAC11 influence the expression of immunosuppressive molecules in MDSCs through regulation of C/EBPβ gene expression.
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functional analysis of hdac11 in plasma cell development and multiple myeloma survival
Blood, 2018Co-Authors: A G M Mostofa, Eva Sahakian, John Powers, Allison Distler, Mark B. Meads, Melissa Alsina, Taiga Nishihori, Rachid Baz, Tuan Nguyen, Javier Pinilla IbarzAbstract:Abstract Background: Histone deacetylases (HDACs) are potential novel therapeutic targets for multiple myeloma (MM) treatment. A pan-HDAC inhibitor (HDI) panobinostat was approved by the FDA in 2015 to treat relapsed/refractory MM patients, and several other HDIs are currently in different phases of clinical trials. However, unfavorable side-effects of the non-selective HDIs necessitate further dissection of the roles of individual HDAC isoforms to best target plasma cell malignancies with minimal toxicity. HDAC11 was recently found to regulate function in key immune cell populations including regulatory T cells, effector T cells, neutrophils, and myeloid-derived suppressor cells (MDSC). Though HDAC11 expression is confirmed in B cells and plasma cells, its functions in these cells remain largely unknown. In this study, we attempted a functional analysis of HDAC11 in plasma cell development along with its pro-tumorigenic function in MM cells. Methods: Mouse models, including a transgenic mouse strain expressing eGFP under the regulation of the HDAC11 promoter (Tg-HDAC11-eGFP), and also an HDA11-deficient mouse (B6.HDAC11-/-) were studied to establish the importance of HDAC11 in plasma cell biology. Pharmacologic inhibition of HDAC11 in MM cell lines was accomplished by using elevenostat, a new HDAC11-selective inhibitor in comparison with pan-inhibitors quisinostat and panobinostat. Impact on viability in human-derived MM cell lines was assessed using the CCK-8 assay, while induction of cell death was measured via detection of activated Caspase-3 and annexin/propidium iodide staining by flow cytometry. Synergy studies were performed by following the Chou-Talalay method for drug combinations. Post-translational modifications and subcellular localization changes induced by HDIs exposure were assessed by western blotting of fractionated cell lysates, while immunoprecipitation and proximity ligation assays (in situ PLA) were used to identify a binding partner for HDAC11. Results: Studies in Tg-HDAC11-eGFP mice reveal that HDAC11 expression in B cell lymphopoiesis is minimally detectable prior to B cell activation but demonstrates strong induction upon maturation into a plasma cell. Consistent with this, plasma cell development is markedly impaired in the absence of HDAC11. The HDAC11-selective inhibitor elevenostat showed significant cytotoxic potential in different MM cell lines that express moderate to high level of HDAC11, with IC50 values ranging 0.6-2.0 µM. Consistently, MM cell lines expressing null/very low level of HDAC11 were insensitive to elevenostat. Moreover, combining elevenostat with proteasome inhibitors bortezomib (BTZ) and carfilzomib resulted in significant synergistic effects evident from combination index (CI) and dose-reduction index (DRI) values measured by CompuSyn software. Elevenostat was also able to re-sensitize BTZ-resistant sub-clones (e.g., RPMI-8226-B25, KAS-6-V10R, and ANBL6-V10R) to BTZ and exhibited superior synergistic effects. Furthermore, elevenostat-treated cells showed a time-dependent alteration in the subcellular localization of HDAC11. HDAC11 gradually disappeared from the nuclear fractions with simultaneous upregulation in cytoplasmic fractions; similar observations were made from pan HDIs (quisinostat and panobinostat) treatment. However, unlike pan HDIs, the elevenostat treatment caused global downregulation of HDAC11 in some MM cell lines at the later time points (72 or 96 hrs), suggesting differential effects of various HDIs. Inhibition of HDAC11 also caused downstream suppression of several pro-tumorigenic factors of MM cells including IRF4 and c-Myc. Additionally, a novel interaction between HDAC11 and IRF4, an essential regulator of PC differentiation and MM survival, was identified by using PLA. HDAC11 dynamically interacts with IRF4 which can be induced by LPS stimulation and inhibited by HDIs, indicating the involvement of HDAC11 in the IRF4-mediated regulatory circuit. Conclusions: We observe that targeted inhibition of HDAC11 can impair MM cell survival and overcome acquired resistance to proteasome inhibitors. Furthermore, we identify IRF4 as a nuclear binding partner of HDAC11 and propose this interaction as a candidate mechanism regulating PC maturation and survival. Disclosures No relevant conflicts of interest to declare.
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hdac11 is a candidate therapeutic target in multiple myeloma
Blood, 2017Co-Authors: Jason Brayer, Eva Sahakian, John Powers, Allison Distler, Mark B. Meads, Melissa Alsina, Taiga Nishihori, Rachid Baz, Tuan Nguyen, Javier PinillaibarzAbstract:Background: Histone deacetylase (HDAC) inhibitors (HDI), although only marginally active as single agent therapy in multiple myeloma (MM), demonstrate an ability to salvage proteasome inhibitors (PIs) and immunomodulatory drugs (IMiDs) responsiveness in refractory patients, thus raising interest in this class of targeted therapeutics. Selective inhibition of particular HDAC isoforms may further improve therapeutic efficacy. HDAC11, the newest member of the HDAC family, is expressed in a progressive manner during B cell development with greatest expression in mature plasma cells (PC). Methods: B cell lymphopoiesis was evaluated using Tg-HDAC11-eGFP mice expressing eGFP regulated by the HDAC11 promoter and congenic mouse strains deficient in HDAC11 expression globally (B6.HDAC11-/-) or targeted to the B cell lineage (CD19Cre.HDAC11-/-). In vitro assays were completed using established human myeloma cell lines that include RPMI-8226, RPMI-8226-B25, OPM2, H929, KMS11, KMS28, KAS6, KAS6R10R, MM1.S, and MM1R10R (kind gift from Dr. Orlowski). Inhibition of HDAC11 in MM cell lines was accomplished by both molecular and pharmacologic approaches. Viability was measured according to activated caspase-3 and Annexin/PI staining by flow cytometry, and by CCK-8 viability assay. Subcellular localization changes induced by HDI exposure were assessed by Western Blot of fractionated cell lysates, while immunoprecipitation and confocal microscopy, using both immunofluorescence and proximity ligation assay techniques, were used to identify IRF4 as a novel nuclear binding partner for HDAC11. Results: Profound eGFP increases in PC of Tg-HDAC11-eGFP mice suggest HDAC11 influences late stage B cell development. Consistent with this, HDAC11 deficiency results in dramatically reduced PC in the bone marrow and periphery. PC depletion in CD19Cre.HDAC11-/- mice, where HDAC11 ablation is restricted to the B cell lineage, suggests activity inherent in B cells rather than via externally derived signals. Initial studies evaluating the effects of quisinostat, a second-generation HDI with increased selectivity that includes HDAC11, showed dose-dependent cytotoxicity versus 10 myeloma cell lines with EC50 measurements in the 1-10nM range. This activity was synergistic with BTZ and carfilzomib (CFZ) in RPMI-8226 cells and degree of synergism was amplified in the BTZ-resistant RPMI-8226-B25 cell line. Subsequent experiments using HDTK-010 (FORMA Therapeutics), an HDAC11-selective HDI, showed dose-dependent cytotoxicity in 21 MM cell lines (EC50 1-10mM). Targeted siRNA-mediated silencing of HDAC11 in RPMI-8226 cells yielded a reduction in cell viability, as measured by Annexin/PI staining and detection of activated caspase-3. An important interaction between HDAC11 and IRF4, an essential regulator of PC differentiation and MM survival, was first identified by immunoprecipitation assay in 8226 cells. This interaction has been confirmed by confocal microscopy using immunofluorescent co-localization and proximity ligation techniques in 8226, MM1.S, OPM2 and H929 cell lines as well as in CD138-enriched MM cells from patient marrow aspirates. Furthermore, this interaction is disrupted by exposure to quisinostat, panobinostat, and HDTK-010. The identification of IRF4 as a putative binding partner for HDAC11 unveils a potential mechanism by which HDAC11 may regulate MM cell survival. Conclusions:We show that MM cell survival can be impaired by targeted inhibition of HDAC11. Furthermore, we identify IRF4 as a nuclear binding partner for HDAC11 and propose this interaction as a candidate mechanism regulating PC maturation and MM cell survival. Disclosures Baz: Sanofi: Research Funding; BMS: Research Funding; merck: Research Funding; takeda: Research Funding; celgene: Honoraria, Research Funding; karyopharm: Research Funding. Pinilla-Ibarz: ARIAD: Consultancy, Honoraria; BMS: Honoraria, Speakers Bureau; Pfizer: Honoraria, Speakers Bureau.
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histone deacetylase 11 a novel epigenetic regulator of myeloid derived suppressor cell expansion and function
Molecular Immunology, 2015Co-Authors: Eva Sahakian, John Powers, Jie Chen, Susan L Deng, Fengdong Cheng, Allison Distler, David M Woods, Jennifer Rockklotz, Andressa L Sodre, Je In YounAbstract: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.
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A Novel Role for Histone Deacetylase 11 (HDAC11) in B Cell Lymphopoiesis and Plasma Cell Survival in Multiple Myeloma
Blood, 2014Co-Authors: Jason Brayer, Eva Sahakian, John Powers, Allison Distler, Mark B. Meads, Susan Deng, Melissa Alsina, Taiga Nishihori, Rachid Baz, Alejandro VillagraAbstract:While multiple myeloma (MM) remains incurable presently, expanded therapeutic options over the past decade have improved patient survival markedly. Proteasome inhibitors have redefined the treatment paradigm for myeloma, often serving as the backbone of front-line treatment. Histone deacetylase (HDAC) inhibitors (HDI), although only marginally active as single agent therapy in hematological malignancies, have demonstrated an ability to salvage bortezomib responsiveness in refractory patients, prompting heightened interest in this class of targeted therapeutics in myeloma. HDAC’s represent a family of enzymes, currently with 11 known members in the classical HDAC family, and subdivided into 4 sub-classes. HDAC11 is currently the only member of the sub-class IV and, as the newest member of the HDAC family, its impact on B cell lymphopoiesis and myeloma development is only starting to be unveiled. Intriguingly, we show that mice with germ-line silencing of HDAC11 (HDAC11KO mice) exhibit a 50% decrease in plasma cells in both the bone marrow and peripheral blood plasma cell compartments relative to wild-type mice. Consistent with this, Tg-HDAC11-eGFP mice, a transgenic strain engineered to express GFP under control of the HDAC11 promoter (Heinz, N Nat. Rev. Neuroscience 2001) reveals that HDAC11 expression is increased in the plasma cell population and to a lesser extent B1 B cells, as compared to earlier lineage stages. Similar observations based on measurements of HDAC11 mRNA were seen in normal human plasma cells. Significant increases in HDAC11 mRNA expression were observed in 7 of 11 primary human multiple myeloma samples and 11 of 12 human myeloma cell lines as compared to normal plasma cells, further emphasizing the potential relevance of HDAC11 to the underlying pathologic processes driving myeloma development and/or survival. Targeted silencing of HDAC11 in RPMI-8226 cells lines using siRNA results in a modest decrease in cell viability as measured by Annexin/PI staining and detection of activated caspase-3. Quisinostat, a second generation pan-HDI, has previously demonstrated activity against human myeloma cell lines in vitro (Stuhmer, Brit J Haematol, 2010), and suppressed bone destruction in an in vivo murine myeloma model (Deleu, Cancer Res, 2009). We similarly observe dose-dependent survival impairment in 10 human myeloma cell lines when cultured in the presence of quisinostat, with EC50’s consistently in the 1-10nM range. Importantly, quisinostat acts synergistically with proteasome inhibitiors (bortezomib and carfilzomib) in RPMI-8226 cells; more importantly, the degree of synergism is amplified in the RPMI-6226-B25 bortezomib-resistant cell line. Although a clear mechanism of action remains to be elucidated, preliminary data suggests that RPMI-8226 cells exposed to quisinostat appear to exhibit a decrease nuclear, but not cytosolic HDAC11. Collectively, these data illustrate a previously unknown role for HDAC11 in plasma cell differentiation and survival. Increased HDAC11 expression seen in myeloma patient specimens and primary myeloma cell lines highlights the potential of HDAC11 as a therapeutic target. Furthermore, we show that quisinostat, a pan-HDI with selectivity towards HDAC11 at lower dosing, acts synergistically with proteasome inhibitors in vitro in proteasome inhibitor sensitive and resistant cell lines. Future work will focus on further elucidating the role of HDAC11 in myeloma survival and drug response, with particular emphasis on proteasome inhibitors. Disclosures No relevant conflicts of interest to declare.
