scholarly journals Axitinib and HDAC Inhibitors Interact to Kill Sarcoma Cells

2021 ◽  
Vol 11 ◽  
Author(s):  
Jane L. Roberts ◽  
Laurence Booth ◽  
Andrew Poklepovic ◽  
Paul Dent
Keyword(s):  
Hdac Inhibitor ◽  
Kinase Inhibitor ◽  
Hdac Inhibitors ◽  
Autophagic Flux ◽  
Drug Induced ◽  
Ampk Signaling ◽  
Knock Down ◽  
Reduce Tumor Growth ◽  
Sarcoma Cells

We have extended our analyses of HDAC inhibitor biology in sarcoma. The multi-kinase inhibitor axitinib interacted with multiple HDAC inhibitors to kill sarcoma cells. Axitinib and HDAC inhibitors interacted in a greater than additive fashion to inactivate AKT, mTORC1 and mTORC2, and to increase Raptor S722/S792 phosphorylation. Individually, all drugs increased phosphorylation of ATM S1981, AMPKα T172, ULK1 S317 and ATG13 S318 and reduced ULK1 S757 phosphorylation; this correlated with enhanced autophagic flux. Increased phosphorylation of ULK1 S317 and of Raptor S722/S792 required ATM-AMPK signaling. ULK1 S757 is a recognized site for mTORC1 and knock down of either ATM or AMPKα reduced the drug-induced dephosphorylation of this site. Combined exposure of cells to axitinib and an HDAC inhibitor significantly reduced the expression of HDAC1, HDAC2, HDAC3, HDAC4, HDAC6 and HDAC7. No response was observed for HDACs 10 and 11. Knock down of ULK1, Beclin1 or ATG5 prevented the decline in HDAC expression, as did expression of a constitutively active mTOR protein. Axitinib combined with HDAC inhibitors enhanced expression of Class I MHCA and reduced expression of PD-L1 which was recapitulated via knock down studies, particularly of HDACs 1 and 3. In vivo, axitinib and the HDAC inhibitor entinostat interacted to significantly reduce tumor growth. Collectively our findings support the exploration of axitinib and HDAC inhibitors being developed as a novel sarcoma therapy.

scholarly journals Tenovin-6 impairs autophagy by inhibiting autophagic flux

2017 ◽  
Vol 8 (2) ◽  
pp. e2608-e2608 ◽  
Author(s):  
Hongfeng Yuan ◽  
Brandon Tan ◽  
Shou-Jiang Gao
Keyword(s):  
Cell Types ◽  
Inhibitory Effect ◽  
Lymphocytic Leukemia ◽  
Autophagic Flux ◽  
Dependent Manner ◽  
Autophagy Pathway ◽  
Sarcoma Cells ◽  
Regulatory Functions

Abstract Tenovin-6 has attracted significant interest because it activates p53 and inhibits sirtuins. It has anti-neoplastic effects on multiple hematopoietic malignancies and solid tumors in both in vitro and in vivo studies. Tenovin-6 was recently shown to impair the autophagy pathway in chronic lymphocytic leukemia cells and pediatric soft tissue sarcoma cells. However, whether tenovin-6 has a general inhibitory effect on autophagy and whether there is any involvement with SIRT1 and p53, both of which are regulators of the autophagy pathway, remain unclear. In this study, we have demonstrated that tenovin-6 increases microtubule-associated protein 1 light chain 3 (LC3-II) level in diverse cell types in a time- and dose-dependent manner. Mechanistically, the increase of LC3-II by tenovin-6 is caused by inhibition of the classical autophagy pathway via impairing lysosomal function without affecting the fusion between autophagosomes and lysosomes. Furthermore, we have revealed that tenovin-6 activation of p53 is cell type dependent, and tenovin-6 inhibition of autophagy is not dependent on its regulatory functions on p53 and SIRT1. Our results have shown that tenovin-6 is a potent autophagy inhibitor, and raised the precaution in interpreting results where tenovin-6 is used as an inhibitor of SIRT1.

scholarly journals Antimalarial Activity of the Anticancer Histone Deacetylase Inhibitor SB939

2012 ◽  
Vol 56 (7) ◽  
pp. 3849-3856 ◽  
Author(s):  
Subathdrage D. M. Sumanadasa ◽  
Christopher D. Goodman ◽  
Andrew J. Lucke ◽  
Tina Skinner-Adams ◽  
Ishani Sahama ◽  
...  
Keyword(s):  
Cerebral Malaria ◽  
Histone Deacetylase ◽  
Hdac Inhibitor ◽  
Antimalarial Activity ◽  
Hdac Inhibitors ◽  
Parasite Life Cycle ◽  
Nonhistone Proteins ◽  
Content Type

ABSTRACTHistone deacetylase (HDAC) enzymes posttranslationally modify lysines on histone and nonhistone proteins and play crucial roles in epigenetic regulation and other important cellular processes. HDAC inhibitors (e.g., suberoylanilide hydroxamic acid [SAHA; also known as vorinostat]) are used clinically to treat some cancers and are under investigation for use against many other diseases. Development of new HDAC inhibitors for noncancer indications has the potential to be accelerated by piggybacking onto cancer studies, as several HDAC inhibitors have undergone or are undergoing clinical trials. One such compound, SB939, is a new orally active hydroxamate-based HDAC inhibitor with an improved pharmacokinetic profile compared to that of SAHA. In this study, thein vitroandin vivoantiplasmodial activities of SB939 were investigated. SB939 was found to be a potent inhibitor of the growth ofPlasmodium falciparumasexual-stage parasitesin vitro(50% inhibitory concentration [IC50], 100 to 200 nM), causing hyperacetylation of parasite histone and nonhistone proteins. In combination with the aspartic protease inhibitor lopinavir, SB939 displayed additive activity. SB939 also potently inhibited thein vitrogrowth of exoerythrocytic-stagePlasmodiumparasites in liver cells (IC50, ∼150 nM), suggesting that inhibitor targeting to multiple malaria parasite life cycle stages may be possible. In an experimentalin vivomurine model of cerebral malaria, orally administered SB939 significantly inhibitedP. bergheiANKA parasite growth, preventing development of cerebral malaria-like symptoms. These results identify SB939 as a potent new antimalarial HDAC inhibitor and underscore the potential of investigating next-generation anticancer HDAC inhibitors as prospective new drug leads for treatment of malaria.

Potent Induction of Human γ Globin Gene Expression by Largazole, a New Histone Deacetylase Inhibitor.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2022-2022
Author(s):  
Hua Cao ◽  
Rui Gao Fei ◽  
Albert A. Bowers ◽  
Thomas J. Greshock ◽  
Tenaya Newkirt ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Histone Deacetylase ◽  
Hdac Inhibitor ◽  
Globin Gene ◽  
Control Level ◽  
Hdac Inhibitors ◽  
Fetal Hemoglobin ◽  
Vitro Effect

Abstract Abstract 2022 Poster Board I-1044 Previous studies have demonstrated that Histone Deacetylase (HDAC) inhibitors such as butyrate and several short chain fatty acids, can induce fetal hemoglobin in humans and animal models; however induction of Hb F is achieved in relatively high concentrations of these compounds. We have previously investigated the induction of human γ globin gene activity by the prototypical HDAC inhibitor, FK228. The results demonstrated that FK228 is a more potent γ globin gene inducer compared to other HDAC inhibitors we have tested before (Am J Hematol. 12:981). In this study, we investigated the induction of human γ globin gene function of largazole and it's thiol analogue in vitro in cultures of normal human adult BFUe and in vivo in the mice carrying a human γ globin transgene. Largazole is a HDAC inhibitor which was recently isolated from a marine vyanobacterium by Luesch and co-workers. Structural features of largazole, a macrocyclic depsopeptide, closely resemble those of FK228, FR901375 and spiruchostatin. We have reported that largazole and numerous synthetic analogues are highly potent Class I histone deacetylase inhibitors (J Am Chem Soc. 130:11219, J Am Chem Soc. 2009 Feb 4). We used flow cytometry to measure the in vitro effect of largazole and it's derivatives on the frequency of HbF-positive erythroblasts in BFUe cultures from normal individuals; real-time quantitative PCR (RT-qPCR) and high performance liquid chromatography (HPLC) were used to measure the in vivo effects of largazole on human γ globin induction in γ transgenic mice carrying a human γ globin gene.. Our results show that largazole and it's thiol derivative are potent γ hemoglobin gene inducers. In the human BFUe cultures, largazole increased the levels of fetal hemoglobin positive cells from 21.9% (control level) to 62.8% at a concentration of 0.1μM; largazole thiol increased the levels of fetal hemoglobin positive cells to 62.0% at a concentration of 1μM. Transgenic mice carrying the human μLCR Aγ construct continue to express the human γ gene in the adult stage (Blood. 77:1326). Largazole was administered through IP injection at the dosages of 0.3mg/kg/day and 0.6mg/kg/day, 5 days per week, for 2 weeks to two cohorts of transgenic mice. Largazole at the dose of 0.3mg/kg/day increased the level of human γ mRNA at the end of injection by 160.7%; at a dose of 0.6mg/kg/day human γ mRNA increased by 174.7%. At the 0.6mg/kg/day dosage the level of fetal hemoglobin in the peripheral blood of the animals increased by 3.4 and 3.2 fold at day 21 and day 28, respectively. These results provide strong in vitro and in vivo evidence that Largazole and it's thiol analogue are potent HbF inducers acting at low concentrations, and thus provide promising alternatives to compounds currently considered for induction of Hb F in patients with sickle cell disease and thalassemia. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Selective Inhibition of Class II HDAC Isoforms 4 and 5 Provides a Promising Therapeutic Intervention for MLL-Rearranged Acute Lymphoblastic Leukemia in Infants

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2206-2206
Author(s):  
Tamara C.A.I. Verbeek ◽  
Susan Arentsen-Peters ◽  
Patricia Garrido Castro ◽  
Sandra Pinhancos ◽  
Kirsten Vrenken ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
Hdac Inhibitor ◽  
Lymphoblastic Leukemia ◽  
Hdac Inhibitors ◽  
Selective Inhibition ◽  
Class Ii ◽  
In Vivo Efficacy ◽  
Pdx Models

Abstract MLL-rearranged acute lymphoblastic leukemia (ALL) is characterized by deregulation of the epigenome and shows susceptibility towards epigenetic perturbators such as histone deacetylase (HDAC) inhibitors. Hence, HDACs represent attractive drug targets and a variety of small molecule HDAC inhibitors have been developed and evaluated for the treatment of hematological malignancies. However, most broad-spectrum inhibitors, which simultaneously target the majority of human HDAC isoforms, often induce toxicity, especially in combination with other therapeutic agents. Therefore, selective inhibition of only one or two HDAC isoforms may represent a better alternative, provided that disease-specific dependency on specific HDACs has been identified. We examined the effects of shRNA-mediated knock-down of the class II HDACs (i.e. HDAC4, HDAC5, HDAC6, HDAC7 and HDAC9) in the MLL-rearranged ALL cell lines SEM and ALL-PO. Except for HDAC9, loss of expression (both on the mRNA and protein level) of all HDACs led to strong reductions in viable cells (0.70 to 0.19-fold; p=0.02-0.0016) in both models due to apoptosis, cell cycle arrest, or a combination thereof. Next, we evaluated the in vitro efficacy of a variety of class II HDAC-specific inhibitors on a panel of MLL-rearranged ALL (n=5) using 4-day viability MTT assays. This revealed that the selective HDAC4/5 inhibitor LMK-235 was able to recapitulate the loss-of-function phenotype of HDAC4 and HDAC5. Dose response curves showed complete growth inhibition in MLL-rearranged ALL cell lines (n=5), as well as in primary MLL-rearranged infant ALL patient samples (n=4), with IC 50 values of ~100 nM and 40-100 nM, respectively. Importantly, at these concentrations, LMK-235 hardly affected whole bone marrow samples derived from healthy individuals (n=2), for which IC 50 values were ~1 µM. To further explore the potential of class II HDAC inhibitor-based therapeutic strategies, we performed a combinatorial drug screen to identify compounds that synergize with LMK-235. For this, a compound library (comprising >200 unique agents) was screened in the absence and presence of varying concentrations of LMK235 in the MLL-rearranged cell line models SEM and ALL-PO. This, and subsequent validation experiments in additional cell line models, revealed that Venetoclax (BCL2 inhibitor), Trametinib (MEK/ERK inhibitor), Ponatinib (multi-tyrosine kinase inhibitor) and Omipalisib (a PI3K/mTOR inhibitor) strongly synergized with LMK-235. Average ZIP synergy scores ranged from 10-30, with peak ZIP scores up to 40. Importantly, synergistic effects were consistent over all concentration combinations tested. The addition of 50-100 nM LMK-235 strongly reduced IC 50 values for Omipalisib, Ponatinib and Venetoclax (0.27-fold p=0.003, 0.11-fold p=0.0005, 0.75-fold p=0.0004, respectively) in both models. In preparation to assess the in vivo efficacy of LMK-235 in patient-derived xenograft (PDX) mouse models of MLL-rearranged infant ALL, pharmacokinetic/pharmacodynamic (PK/PD) analysis was performed in immunodeficient NSG mice (n=5). For this, mice were treated with 20 mg/kg of LMK-235, daily administered via intraperitoneal injections for a total of 29 days. While none of the mice showed signs of toxicity or weight loss, LMK-235 plasma levels were stably maintained at concentrations that are highly effective against MLL-rearranged ALL cells in vitro. Taken together, these data demonstrate that various class II HDAC isoforms are targetable vulnerabilities in MLL-rearranged ALL and that pharmaceutical inhibition of HDAC4/5 by LMK-235 represents an attractive therapeutic option. Moreover, high levels of synergy observed between this HDAC inhibitor and various agents belonging to drug classes already reported to be effective against MLL-rearranged ALL, warrants pre-clinical evaluation in vivo. Currently, the assessment of the in vivo efficacy of LMK-235 monotherapy in MLL-rearranged infant ALL PDX models is in progress, after which promising synergistic HDAC inhibitor-based drug combinations will be evaluated. To determine the additional therapeutic value, the efficacy of LMK-235 and promising synergistic combinations will be evaluated in the background of conventional combination chemotherapy, where PDX models will receive a mouse-adapted version of induction therapy currently applied for treatment of MLL-rearranged infant ALL patients. Disclosures No relevant conflicts of interest to declare.

scholarly journals Rapid In Vivo Validation of HDAC Inhibitor-Based Treatments in Neuroblastoma Zebrafish Xenografts

2020 ◽  
Vol 13 (11) ◽  
pp. 345
Author(s):  
Jagoda K Wrobel ◽  
Sara Najafi ◽  
Simay Ayhan ◽  
Charlotte Gatzweiler ◽  
Damir Krunic ◽  
...  
Keyword(s):  
Tumor Cell ◽  
Hdac Inhibitor ◽  
Drug Testing ◽  
Hdac Inhibitors ◽  
Metastatic Tumor ◽  
Tumor Cell Death ◽  
Tail Region ◽  
In Vivo Evaluation ◽  
Combination Treatments

The survival rate among children with relapsed neuroblastomas continues to be poor, and thus new therapeutic approaches identified by reliable preclinical drug testing models are urgently needed. Zebrafish are a powerful vertebrate model in preclinical cancer research. Here, we describe a zebrafish neuroblastoma yolk sac model to evaluate efficacy and toxicity of histone deacetylase (HDAC) inhibitor treatments. Larvae were engrafted with fluorescently labeled, genetically diverse, established cell lines and short-term cultures of patient-derived primary cells. Engrafted tumors progressed locally and disseminated remotely in an intact environment. Combination treatments involving the standard chemotherapy doxorubicin and HDAC inhibitors substantially reduced tumor volume, induced tumor cell death, and inhibited tumor cell dissemination to the tail region. Hence, this model allows for fast, cost-efficient, and reliable in vivo evaluation of toxicity and response of the primary and metastatic tumor sites to drug combinations.

Induction of Fetal Hemoglobin by Inactivation of HDAC1 or HDAC2 without Altering Cellular Proliferation

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 354-354
Author(s):  
Erica B. Esrick ◽  
Jian Xu ◽  
Katherine Lin ◽  
Marie Ellen McConkey ◽  
Alyse Frisbee ◽  
...  
Keyword(s):  
Hdac Inhibitor ◽  
Cell Cycle Progression ◽  
Hdac Inhibitors ◽  
Fetal Hemoglobin ◽  
Fold Increase ◽  
Globin Mrna ◽  
Gamma Globin ◽  
Hydroxyurea Treatment

Abstract Abstract 354 Histone deacetylase (HDAC) inhibitors are effective inducers of fetal hemoglobin, and prior studies have shown that selective inactivation of HDAC1 or HDAC2 is sufficient to induce fetal hemoglobin in vitro. In our current work, we demonstrate that HDAC1 and HDAC2 are attractive targets for clinical translation for two reasons: 1) Selective inhibition will decrease off-target effects that currently limit the use of hydroxyurea and pan-HDAC inhibitors, and 2) HDAC inhibitors induce fetal hemoglobin in various preclinical models, and they can be combined with hydroxyurea to achieve further fetal hemoglobin induction. To investigate off-target effects, we selectively inactivated HDAC1, HDAC2 or HDAC3 in human erythroid progenitor cells, and examined the effect of each knockdown on cellular cytotoxicity and cell cycle progression. Although knockdown of HDAC3 negatively influenced growth, selective knockdown of HDAC1 or HDAC2 had no effect on expansion of erythroid progenitors. In addition, knockdown of HDAC2 does not block cell cycle progression. These data support the possibility that an HDAC1- or HDAC2-specific inhibitor may offer a therapeutic advantage by reducing side effects, while maintaining robust HbF induction. Armed with this knockdown data, we are now investigating HDAC inhibitor compounds of various selectivity in in vitro and in vivo models. To perform optimal clinical trials, and ultimately to benefit the most sickle cell disease patients, it would be ideal to combine HDAC inhibitor treatment with hydroxyurea. A combination treatment approach may ameliorate some of the limitations of hydroxyurea use, such as the unpredictable effect on fetal hemoglobin levels, and the lack of benefit in beta thalassemia patients. First, we combined HDAC2 inactivation with hydroxyurea treatment in vitro. Human bone marrow-derived CD34+ cells were infected with lentiviruses containing an shRNA targeting either HDAC2 or a luciferase control gene. The cells were then treated on day 4 of erythroid differentiation with hydroxyurea (10–20 uM dose). Compared to the untreated luciferase control samples, we observed a 7–9-fold increase in gamma-globin expression in the untreated HDAC2-knockdown samples, a 2.5-fold increase in the hydroxyurea-treated luciferase control samples, and a trend toward an additive effect on gamma-globin induction in the cells where HDAC2 knockdown was combined with hydroxyurea treatment. To investigate the effects of HDAC inhibitors in vivo, we administered compounds to BCL11A conditional knockout transgenic mice (by erythroid-selective EpoR-GFP Cre) containing the human beta-globin locus. As reported previously, BCL11A inactivation powerfully de-repressed gamma-globin expression, and administration of an HDAC inhibitor, SAHA, led to a further elevation of gamma-globin mRNA. We now demonstrate that administration of another pan-HDAC inhibitor, panobinostat (LBH589), results in an additional 1.5- to 2.5-fold increase in gamma-globin mRNA relative to pre-treatment baseline. We are currently evaluating the combination of panobinostat and hydroxyurea in these mice to confirm that the compounds have an additive effect in vivo as well as in vitro. Taken together, these experiments indicate that inhibiting HDAC1 or HDAC2 is a promising therapeutic approach to increasing fetal hemoglobin levels in patients with beta-hemoglobinopathies, both alone and in combination with hydroxyurea. Disclosures: Bradner: Acetylon: .

scholarly journals Cytoplasmic Interactions between the Glucocorticoid Receptor and HDAC2 Regulate Osteocalcin Expression in VPA-Treated MSCs

Cells ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 217 ◽  
Author(s):  
Marcella La Noce ◽  
Luigi Mele ◽  
Luigi Laino ◽  
Giovanni Iolascon ◽  
Gorizio Pieretti ◽  
...  
Keyword(s):  
Glucocorticoid Receptor ◽  
Hdac Inhibitor ◽  
Histone Deacetylases ◽  
Molecular Mechanisms ◽  
Severe Combined Immunodeficiency ◽  
Hdac Inhibitors ◽  
Stem Cell Differentiation ◽  
Mechanistic Explanation ◽  
Nonobese Diabetic

Epigenetic regulation has been considered an important mechanism for influencing stem cell differentiation. In particular, histone deacetylases (HDACs) have been shown to play a role in the osteoblast differentiation of mesenchymal stem cells (MSCs). In this study, the effect of the HDAC inhibitor, valproic acid (VPA), on bone formation in vivo by MSCs was determined. Surprisingly, VPA treatment, unlike other HDAC inhibitors, produced a well-organized lamellar bone tissue when MSCs–collagen sponge constructs were implanted subcutaneously into nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice, although a decrease of osteocalcin (OC) expression was observed. Consequently, we decided to investigate the molecular mechanisms by which VPA exerts such effects on MSCs. We identified the glucocorticoid receptor (GR) as being responsible for that downregulation, and suggested a correlation between GR and HDAC2 inhibition after VPA treatment, as evidenced by HDAC2 knockdown. Furthermore, using co-immunoprecipitation analysis, we showed for the first time in the cytoplasm, binding between GR and HDAC2. Additionally, chromatin immunoprecipitation (ChIP) assays confirmed the role of GR in OC downregulation, showing recruitment of GR to the nGRE element in the OC promoter. In conclusion, our results highlight the existence of a cross-talk between GR and HDAC2, providing a mechanistic explanation for the influence of the HDAC inhibitor (namely VPA) on osteogenic differentiation in MSCs. Our findings open new directions in targeted therapies, and offer new insights into the regulation of MSC fate determination.

scholarly journals CAPN1 (Calpain1)-Mediated Impairment of Autophagic Flux Contributes to Cerebral Ischemia-Induced Neuronal Damage

Stroke ◽  
2021 ◽  
Author(s):  
Yueyang Liu ◽  
Xiaohang Che ◽  
Haotian Zhang ◽  
Xiaoxiao Fu ◽  
Yang Yao ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Kinase Inhibitor ◽  
Neuronal Damage ◽  
Neuronal Cell ◽  
In Vivo Model ◽  
Autophagic Flux ◽  
Autophagosome Formation

Background and Purpose: CAPN1 (calpain1)—an intracellular Ca 2+ -regulated cysteine protease—can be activated under cerebral ischemia. However, the mechanisms by which CAPN1 activation promotes cerebral ischemic injury are not defined. Methods: In the present study, we used adeno-associated virus-mediated genetic knockdown and pharmacological blockade (MDL-28170) of CAPN1 to investigate the role of CAPN1 in the regulation of the autophagy-lysosomal pathway and neuronal damage in 2 models, rat permanent middle cerebral occlusion in vivo model and oxygen-glucose–deprived primary neuron in vitro model. Results: CAPN1 was activated in the cortex of permanent middle cerebral occlusion–operated rats and oxygen-glucose deprivation–exposed neurons. Genetic and pharmacological inhibition of CAPN1 significantly attenuated ischemia-induced lysosomal membrane permeabilization and subsequent accumulation of autophagic substrates in vivo and in vitro. Moreover, inhibition of CAPN1 increased autophagosome formation by decreasing the cleavage of the autophagy regulators BECN1 (Beclin1) and ATG (autophagy-related gene) 5. Importantly, the neuron-protective effect of MDL-28170 on ischemic insult was reversed by cotreatment with either class III-PI3K (phosphatidylinositol 3-kinase) inhibitor 3-methyladenine or lysosomal inhibitor chloroquine (chloroquine), suggesting that CAPN1 activation-mediated impairment of autophagic flux is crucial for cerebral ischemia-induced neuronal damage. Conclusions: The present study demonstrates for the first time that ischemia-induced CAPN1 activation impairs lysosomal function and suppresses autophagosome formation, which contribute to the accumulation of substrates and aggravate the ischemia-induced neuronal cell damage. Our work highlights the vital role of CAPN1 in the regulation of cerebral ischemia–mediated autophagy-lysosomal pathway defects and neuronal damage.

scholarly journals HDAC Inhibitors Potentiate the Activity of the BCR/ABL Kinase Inhibitor KW-2449 in Imatinib-Sensitive or -Resistant BCR/ABL+ Leukemia Cells In Vitro and In Vivo

2011 ◽  
Vol 17 (10) ◽  
pp. 3219-3232 ◽  
Author(s):  
Tri Nguyen ◽  
Yun Dai ◽  
Elisa Attkisson ◽  
Lora Kramer ◽  
Nicholas Jordan ◽  
...  
Keyword(s):  
Kinase Inhibitor ◽  
Hdac Inhibitors ◽  
Leukemia Cells ◽  
Abl Kinase

A Critical Role for STAT-3 Dependent Induction of Indoleamine 2, 3 Dioxygenase in Histone Deacetylase Inhibitors Mediated the Regulation of GVHD.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 351-351
Author(s):  
Yaping Sun ◽  
Elizabeth Weisiger ◽  
Tomomi Toubai ◽  
Charles Dinarello ◽  
James L. Ferrara ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cell ◽  
Histone Deacetylase ◽  
Protein Interaction ◽  
Hdac Inhibitor ◽  
Luciferase Activity ◽  
Hdac Inhibitors ◽  
T Cell Proliferation ◽  
Indoleamine 2

Abstract Histone deacetylase (HDAC) inhibitors reduce experimental acute graft-versus-host disease (GVHD) and recent work by us and others suggest that HDAC inhibitors regulate dendritic cell (DC) function. However, the critical cellular and molecular mechanisms underpinning these observations are not known. We investigated the mechanisms by utilizing two HDAC inhibitors, suberoylanilide hydroxamic acid (SAHA) and ITF 2357. Pretreatment of murine bone marrow (BM) and human peripheral blood mononuclear cell derived DCs with either HDAC inhibtors and stimulated with TLR ligands such as LPS caused a significant reduction in the secretion of TNF-α compared to the untreated controls (P< 0.01). Pre-treatment also significantly reduced the DC mediated in vitro and in vivo stimulation of allogeneic T cell proliferation (P<0.05). SAHA and ITF 2357 increased expression of indoleamine 2, 3-dioxygenase (IDO) at both mRNA and protein levels. Blockade of IDO induction with specific small interfering RNA (siRNA) in the wild type (WT) DCs and those derived from IDO deficient (IDO−/−) animals confirmed a functional role for IDO in the HDAC inhibitor mediated regulation TNFα secretion and allo-T cell proliferation. DNA-protein interaction analysis with ChIP assay demonstrated that both acetylated histone(H) 4 and STAT3 bound to murine IDO promoter. Using TESS DNA soft-wear analysis we found two potential STAT3 binding Gamma Activated Sites (GAS sites) in the IDO promoter and it was recently reported that acetylation of STAT3 is sufficient for its activation (Yuan, et al. Science 2005). We therefore sought to determine whether direct acetylation of STAT3 by the HDAC inhibitors is critical for the induction of IDO in DCs. SAHA or ITF2357 treatment induced acetylation, activation and dimerization of STAT-3 as determined by protein-protein interaction studies. Co-culture studies with JSI-124, an inhibitor of STAT3 signaling, demonstrated that STAT3 is critical for induction of IDO by the HDAC inhibitors. Functional relevance was confirmed by the lack of HDAC inhibitor induced suppression of DC function when co-treated with JSI-124. We next cloned 1500bp DNA fragment upstream of mouse IDO gene start codon and attached it to luciferase gene and peformed mutagenesis studies to evaluate for luciferase activity. Deletion of the GAS regions or treatment with JSI-124 impaired luciferase activity of the IDO promoter constructs demonstrating that STAT3 is necessary and sufficient for transcriptional induction of IDO by the HDAC inhibitors. To specifically address the in vivo relevance of IDO induction by HDAC inhibitors in only the host type DCs, we generated [B6 → B6] and [IDO−/−B6 → B6] BM chimeras and utilized them in a well characterized [BALB/c B6] mouse model of acute GVHD. [B6 → B6] and [IDO−/− B6 → B6] animals received 800 Gy on day −1 and were treated orally with of 50mg/kg of ITF 2357 or diluent on days −1 to +2. Mice were transplanted on day 0 with 3 x 106 T cells and 5 x 106 BM from either syngeneic B6 or allogeneic BALB/c donors. Treatment with ITF 2357 resulted in significantly better survival in the allogeneic [B6 → B6] animals (80% vs. 40%, P < 0.02) but did not confer any survival benefit to the [IDO−/− B6 → B6] animals when compared with diluent treated recipients [20% vs. 30%, P = NS]. Our data thus demonstrate a novel molecular pathway in modulation of GVHD through a STAT3 dependent induction of IDO in the host DCs.

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