panobinostat and entinostat

Deacetylase (DAC) inhibitors are promising new anticancer drugs that have complex mechanisms of action, including induction of cell-cycle arrest and apoptosis, inhibition of angiogenesis and induction of a favorable anti-tumor immune response. Panobinostat, a potent inhibitor of DAC 1-11 enzymatic activity, has demonstrated a significant in vitro antiproliferative activity against classical Hodgkin's lymphoma (cHL) cell lines in addition to a promising clinical activity in early Phase I studies in patients with relapsed cHL. In a recently completed large Phase II study in patients with relapsed cHL, panobinostat reduced tumor measurements in 74% of patients, including 23% partial and 4% complete remissions. In this article, we review the status of panobinostat drug development and compare its activity to those of other DAC inhibitors in patients with relapsed cHL. Future investigations should focus on designing rational combination regimens and identifying predictive markers that will assist in selecting patients who are likely to benefit from this novel therapy.

Topics: Benzamides; Clinical Trials as Topic; Drug Evaluation, Preclinical; Histone Deacetylase Inhibitors; Histone Deacetylases; Hodgkin Disease; Humans; Hydroxamic Acids; Indoles; Panobinostat; Pyridines; Pyrimidines; Vorinostat

Over the last 5 years, a plethora of histone deacetylase inhibitors (HDACi) have been evaluated in clinical trials. These drugs have in common the ability to hyperacetylate both histone and nonhistone targets, resulting in a variety of effects on cancer cells, their microenvironment, and immune responses. To date, responses with single agent HDACi have been predominantly observed in advanced hematologic malignancies including T-cell lymphoma, Hodgkin lymphoma, and myeloid malignancies. Therefore, in this review we focus upon hematologic malignancies. Generally HDACi are well tolerated with the most common acute toxicities being fatigue, gastrointestinal, and transient cytopenias. Of note, few patients have been treated for prolonged periods of time and little is known about long-term toxicities. The use of the biomarker of histone hyperacetylation has been useful as a guide to target specificity, but generally does not predict for response and the search for more clinically relevant biomarkers must continue.

Topics: Antibiotics, Antineoplastic; Benzamides; Clinical Trials as Topic; Depsipeptides; Drug Therapy, Combination; Enzyme Inhibitors; Hematologic Neoplasms; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Indoles; Panobinostat; Pyridines; Pyrimidines; Sulfonamides; Vorinostat

Histone deacetylase inhibitors (HDACi) are a new class of antineoplastic agents with demonstrable preclinical antitumor activity in both in vitro and in vivo studies in a wide range of malignancies. Based on these preclinical findings, in recent years HDACi have undergone a rapid phase of clinical development with many HDACi entering Phase I-III clinical trials, both as single agents and in combination with other therapies. Favorable clinical responses have been demonstrated in cutaneous T-cell lymphoma with emerging evidence of clinical activity in other types of lymphoma and, to date, a good toxicity profile. Solid tumor responses to single agent and combination therapies have also been reported, paving the way for larger studies in this field. In this review we discuss the recent advances in the clinical development of HDACi and their current therapeutic role in lymphoma and solid malignancies.

Topics: Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Benzamides; Depsipeptides; Drug Resistance, Neoplasm; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Indoles; Lymphoma; Neoplasm Recurrence, Local; Neoplasms; Panobinostat; Pyridines; Pyrimidines; Vorinostat

Using rigorous and clinically relevant experimental design and analysis standards, in this study, we investigated the potential of histone deacetylase (HDAC) inhibitors panobinostat and entinostat to enhance recovery of motor function after photothrombotic stroke in male mice. Panobinostat, a pan-HDAC inhibitor, is a FDA-approved drug for certain cancers, whereas entinostat is a class-I HDAC inhibitor in late stage of clinical investigation. The drugs were administered every other day (panobinostat-3 or 10 mg/kg; entinostat-1.7 or 5 mg/kg) starting from day 5 to 15 after stroke. To imitate the current standard of care in stroke survivors, i.e., physical rehabilitation, the animals run on wheels (2 h daily) from post-stroke day 9 to 41. The predetermined primary end point was motor recovery measured in two tasks of spontaneous motor behaviors in grid-walking and cylinder tests. In addition, we evaluated the running distance and speed throughout the study, and the number of parvalbumin-positive neurons in medial agranular cortex (AGm) and infarct volumes at the end of the study. Both sensorimotor tests revealed that combination of physical exercise with either drug did not substantially affect motor recovery in mice after stroke. This was accompanied by negligible changes of parvalbumin-positive neurons recorded in AGm and comparable infarct volumes among experimental groups, while dose-dependent increase in acetylated histone 3 was observed in peri-infarct cortex of drug-treated animals. Our observations suggest that add-on panobinostat or entinostat therapy coupled with limited physical rehabilitation is unlikely to offer therapeutic modality for stroke survivors who have motor dysfunction.

Topics: Animals; Benzamides; Histone Deacetylase Inhibitors; Ischemic Stroke; Male; Mice; Panobinostat; Pyridines

High grade serous ovarian cancer (HGSOC) is the most common and aggressive ovarian cancer subtype with the worst clinical outcome due to intrinsic or acquired drug resistance. Standard treatment involves platinum compounds. Cancer development and chemoresistance is often associated with an increase in histone deacetylase (HDAC) activity. The purpose of this study was to examine the potential of HDAC inhibitors (HDACi) to increase platinum potency in HGSOC. Four HGSOC cell lines with different cisplatin sensitivity were treated with combinations of cisplatin and entinostat (class I HDACi), panobinostat (pan-HDACi), or nexturastat A (class IIb HDACi), respectively. Inhibition of class I HDACs by entinostat turned out superior in increasing cisplatin potency than pan-HDAC inhibition in cell viability assays (MTT), apoptosis induction (subG1), and caspase 3/7 activation. Entinostat was synergistic with cisplatin in all cell lines in MTT and caspase activation assays. MTT assays gave combination indices (CI values) < 0.9 indicating synergism. The effect of HDAC inhibitors could be attributed to the upregulation of pro-apoptotic genes (

Topics: Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Benzamides; Cell Line, Tumor; Cell Survival; Cisplatin; Cystadenocarcinoma, Serous; Drug Synergism; Female; Histone Deacetylase Inhibitors; Histone Deacetylases; Humans; Hydroxamic Acids; Ovarian Neoplasms; Panobinostat; Phenylurea Compounds; Pyridines

Class-selective histone deacetylase (HDAC) inhibitors were designed to improve safety profiles and therapeutic effectiveness in the treatment of multiple cancers relative to pan-HDAC inhibitors. However, the underlying mechanisms for their therapeutic and cardiotoxic potentials remain poorly understood. Cardiac sodium currents (I

Topics: Animals; Benzamides; Blotting, Western; Cells, Cultured; Connexin 43; Gap Junctions; Histone Deacetylase Inhibitors; Hydroxamic Acids; Indoles; Mice; Mice, Inbred C57BL; Myocytes, Cardiac; NAV1.5 Voltage-Gated Sodium Channel; Panobinostat; Patch-Clamp Techniques; Pyridines; Pyrimidines

Expression of MHC class II pathway proteins in ovarian cancer correlates with prolonged survival. Murine and human ovarian cancer cells were treated with epigenetic modulators - histone deacetylase inhibitors and a DNA methyltransferase inhibitor. mRNA and protein expression of the MHC II pathway were evaluated by qPCR and flow cytometry. Treatment with entinostat and azacytidine of ID8 cells in vitro increased mRNA levels of Cd74, Ciita, and H2-Aa, H2-Eb1. MHC II and CD74 protein expression were increased after treatment with either agent. A dose dependent response in mRNA and protein expression was seen with entinostat. Combination treatment showed higher MHC II protein expression than with single agent treatment. In patient derived xenografts, CIITA, CD74, and MHC II mRNA transcripts were significantly increased after combination treatment. Expression of MHC II on ovarian tumors in MISIIR-Tag mice was increased with both agents relative to control. Combination treatment significantly reduced ID8 tumor growth in immune-competent mice. Epigenetic treatment increases expression of MHC II on ovarian cancer cells and impedes tumor growth. This approach warrants further study in ovarian cancer patients.

Topics: Animals; Antimetabolites, Antineoplastic; Azacitidine; Benzamides; Cell Line, Tumor; Disease Models, Animal; DNA Methylation; Dose-Response Relationship, Drug; Drug Synergism; Epigenesis, Genetic; Female; Gene Expression Regulation, Neoplastic; Histocompatibility Antigens Class II; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Indoles; Mice; Ovarian Neoplasms; Panobinostat; Pyridines; RNA, Messenger; Transcription, Genetic; Tumor Burden; Xenograft Model Antitumor Assays

Aberrant histone deacetylase (HDAC) activity often correlates with neoplastic transformation and inhibition of HDACs by small molecules has emerged as a promising strategy to treat hematological malignancies in particular. Treatment with HDAC inhibitors (HDACis) often prompts tumor cells to undergo apoptosis, thereby causing a caspase-dependent cleavage of target proteins. An unexpectedly large number of proteins are in vivo caspase substrates and defining caspase-mediated substrate specificity is a major challenge. In this chapter we demonstrate that the hematopoietic transcription factor PU.1 becomes cleaved after treatment of acute myeloid leukemia (AML) cells with the HDACis LBH589 (panobinostat) or MS-275 (entinostat). To define caspase specificity for PU.1, an in vitro caspase assay including caspases 1-10 with in vitro-translated PU.1 is described in detail.

Topics: Antineoplastic Agents; Benzamides; Blotting, Western; Caspase 8; Electrophoresis, Polyacrylamide Gel; Enzyme Activation; Gene Expression Regulation, Neoplastic; HEK293 Cells; Histone Deacetylase Inhibitors; Histone Deacetylases; HL-60 Cells; Humans; Hydroxamic Acids; Indoles; K562 Cells; Panobinostat; Proteolysis; Proto-Oncogene Proteins; Pyridines; Substrate Specificity; Trans-Activators; Transfection

Histone deacetylase inhibitors (HDACi) are used as therapeutics for several B cell-derived malignancies. Furthermore, they have been shown to modulate the response of the immune system, like the B cell function. HDACi treatment affects differentiation, proliferation, and survival of B cells. Here we describe how to investigate the effects of HDACi treatment on naïve B cells regarding class-switch recombination (CSR) in vitro using flow cytometry.

Topics: Animals; B-Lymphocytes; Benzamides; Carbazoles; Cell Cycle; Cell Differentiation; Cell Proliferation; Cell Survival; Cytokines; Flow Cytometry; Histone Deacetylase Inhibitors; Histone Deacetylases; Hydroxamic Acids; Immunoglobulin Class Switching; Immunoglobulins; Immunomagnetic Separation; Indoles; Lipopolysaccharides; Mice; Mice, Inbred C57BL; Panobinostat; Primary Cell Culture; Pyridines; Recombination, Genetic

Histone deacetylases (HDACs) catalyze the deacetylation of lysine residues in their target proteins. This biochemical modification can have profound effects on the functions of these proteins and a dysregulation of HDAC activity contributes to severe diseases, including neoplastic transformation. In the following chapter, we present a strategy that allows to distinguish between the inhibition of the class I HDACs HDAC1, 2, and 3 and of the class IIb HDAC HDAC6. This method is based on Western blot and relies on the detection of hyperacetylated substrates of class I or class IIb HDACs in lysates from cells that were treated with histone deacetylase inhibitors (HDACi).

Topics: Acetylation; Animals; Benzamides; Blotting, Western; Cell Line, Tumor; Epigenesis, Genetic; Epithelial Cells; Histone Deacetylase 1; Histone Deacetylase 2; Histone Deacetylase 6; Histone Deacetylase Inhibitors; Histone Deacetylases; Histones; Humans; Hydroxamic Acids; Indoles; Mice; Monocytes; Panobinostat; Protein Processing, Post-Translational; Pyridines; Valproic Acid

The differentiation of hematopoietic stem cells into mature blood cells is a highly ordered process and dysregulation of this process can lead to leukemogenesis. Agents that are used to cure acute promyelocytic leukemia (APL) can induce differentiation and/or apoptosis. Here, we describe how effects of all-trans retinoic acid (ATRA) and histone deacetylase inhibitors (HDACi) on APL cell differentiation can be evaluated by immunoblotting and by flow cytometry. We show how the levels of differentiation-associated transcription factors of the CCAAT enhancer binding protein (C/EBP) family can be determined by Western blot and we explain how the cell surface expression of the leukocyte surface antigen CD11b can be measured by flow cytometry.

Topics: Apoptosis; Benzamides; CCAAT-Enhancer-Binding Protein-beta; CCAAT-Enhancer-Binding Proteins; CD11b Antigen; Cell Differentiation; Flow Cytometry; Gene Expression Regulation, Leukemic; Hematopoietic Stem Cells; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Immunoblotting; Indoles; Panobinostat; Pyridines; Tretinoin

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

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

We reported that the class I HDAC inhibitor entinostat induced apoptosis in erbB2-overexpressing breast cancer cells via downregulation of erbB2 and erbB3. Here, we study the molecular mechanism by which entinostat dual-targets erbB2/erbB3. Treatment with entinostat had no effect on erbB2/erbB3 mRNA, suggesting a transcription-independent mechanism. Entinostat decreased endogenous but not exogenous erbB2/erbB3, indicating it did not alter their protein stability. We hypothesized that entinostat might inhibit erbB2/erbB3 protein translation via specific miRNAs. Indeed, entinostat significantly upregulated miR-125a, miR-125b, and miR-205, that have been reported to target erbB2 and/or erbB3. Specific inhibitors were then used to determine whether these miRNAs had a causal role in entinostat-induced downregulation of erbB2/erbB3 and apoptosis. Transfection with a single inhibitor dramatically abrogated entinostat induction of miR-125a, miR-125b, or miR-205; however, none of the inhibitors blocked entinostat action on erbB2/erbB3. In contrast, co-transfection with two inhibitors not only reduced their corresponding miRNAs, but also significantly abrogated entinostat-mediated reduction of erbB2/erbB3. Moreover, simultaneous inhibition of two, but not one miRNA significantly attenuated entinostat-induced apoptosis. Interestingly, although the other HDAC inhibitors, such as SAHA and panobinostat, exhibited activity as potent as entinostat to induce growth inhibition and apoptosis in erbB2-overexpressing breast cancer cells, they had no significant effects on the three miRNAs. Instead, both SAHA- and panobinostat-decreased erbB2/erbB3 expression correlated with the reduction of their mRNA levels. Collectively, we demonstrate that entinostat specifically induces expression of miR-125a, miR-125b, and miR-205, which act in concert to downregulate erbB2/erbB3 in breast cancer cells. Our data suggest that epigenetic regulation via miRNA-dependent or -independent mechanisms may represent a novel approach to treat breast cancer patients with erbB2-overexpressing tumors.

Topics: Antineoplastic Agents; Apoptosis; Benzamides; Breast Neoplasms; Cell Line, Tumor; Epigenesis, Genetic; Gene Expression Regulation, Neoplastic; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Indoles; MicroRNAs; Panobinostat; Protein Biosynthesis; Pyridines; Receptor, ErbB-2; Receptor, ErbB-3; Signal Transduction

Chronic lymphocytic leukemia (CLL) demonstrates a global down-regulation of miR-15a and miR-16 and a selective silencing of the related miR-29b in aggressive disease. Deletions in chromosome 13 [del(13q14)] partially account for the loss of expression of miR-15a and miR-16, but the mechanisms by which miR-29b becomes silenced is unknown. In the present study, we show that the histone deacetylases (HDACs) are overexpressed in CLL and mediate the epigenetic silencing of miR-15a, miR-16, and miR-29b. HDAC inhibition triggered the accumulation of the transcriptionally activating chromatin modification H3K4me2 and restored the expression of miR-15a, miR-16, and miR-29b in approximately 35% of samples. Ectopic expression of miR-15a and miR-16 and HDAC inhibition-induced expression of miR-15a, miR-16, or miR-29b in primary CLL cells was associated with declines in the levels of Mcl-1, but not Bcl-2, mitochondrial dysfunction, and induction of cell death. Therefore, our results show that HDACs aberrantly silence the expression of the critical tumor suppressors miR-15a, miR-16, and miR-29b in CLL. Deacetylase inhibition may be a therapeutic strategy that restores the expression of these miRs to antagonize Mcl-1, an important survival protein in these cells. Consequently, CLL patients who exhibit such epigenetic silencing may benefit from HDAC inhibitor-based therapy.

Topics: Adult; Benzamides; Female; Gene Expression Regulation, Leukemic; Gene Silencing; Histone Deacetylase Inhibitors; Histone Deacetylases; Humans; Hydroxamic Acids; Indoles; Leukemia, Lymphocytic, Chronic, B-Cell; Male; MicroRNAs; Panobinostat; Primary Cell Culture; Pyridines; Tumor Cells, Cultured

Anaplastic thyroid cancer cells are characterized by a mesenchymal phenotype, as revealed by spindle-shaped cells and absent or reduced levels of E-cadherin. Epigenetic silencing is considered one of the leading mechanisms of E-cadherin impairment, which causes the acquisition of the invasive and metastatic phenotype of anaplastic thyroid cancer.. In this study we investigated the effects of histone deacetylase inhibition on E-cadherin expression, cell motility, and invasion in anaplastic thyroid cancer cell cultures.. Three stabilized cell lines and primary cultures of anaplastic thyroid cancer were treated with various histone deacetylase inhibitors. After treatment, we evaluated histone acetylation by Western blotting and E-cadherin expression by RT-real time PCR. The proper localization of E-cadherin/β-catenin complex was assessed by immunofluorescence and Western blot. Transcription activity of β-catenin was measured by luciferase reporter gene and cyclin D1 expression. The effect on cell motility and invasion was studied both in vitro using scratch-wound and transwell invasion assays and in anaplastic thyroid carcinomas tumor xenografts in mice in vivo.. Histone deacetylase inhibition induced the E-cadherin expression and the proper membrane localization of the E-cadherin/β-catenin complex, leading to reduced cancer cell migration and invasion.. We here demonstrate an additional molecular mechanism for the anticancer effect of histone deacetylase inhibition. The antiinvasive effect in addition to the cytotoxic activity of histone deacetylase inhibitors opens up therapeutic perspectives for the anaplastic thyroid tumor that does not respond to conventional therapy.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Benzamides; beta Catenin; Cadherins; Cell Movement; Down-Regulation; Gene Expression Regulation, Neoplastic; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Indoles; Mice; Mice, SCID; Neoplasm Invasiveness; Panobinostat; Protein Transport; Pyridines; Thyroid Carcinoma, Anaplastic; Thyroid Neoplasms; Tumor Cells, Cultured; Xenograft Model Antitumor Assays

Adult T-cell leukemia/lymphoma (ATL) is a highly aggressive disease with a poor prognosis in which nuclear factor kappa B (NF-kappaB) is thought to play a role. This study explored the effects of histone deacetylase inhibitors (HDACIs) MS-275, suberoylanilide hydroxamic acid (SAHA), and LBH589 on both human T-cell lymphotropic virus type I (HTLV-1)-infected T cells (MT-1, -2, -4, and HUT102) and freshly isolated ATL cells harvested from patients. HDACIs effectively inhibited the proliferation of these cells. For example, MS-275, SAHA, and LBH589 effectively inhibited the proliferation of MT-1 cells with ED(50s) of 6microM, 2.5microM, and 100nM, respectively, as measured by 3-(4,5-dimethylithiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay on day 2 of culture. In addition, HDACIs induced cell cycle arrest at the G2/M phase and apoptosis of HTLV-1-infected T-cells in conjunction with regulation of apoptosis-related proteins. Electrophoretic mobility shift assay showed that exposure of HTLV-1-infected T-cells to HDACIs for 48h inhibited formation of the NF-kappaB/DNA binding complex. Moreover, we found that HDACIs accumulated NF-kappaB and inhibitory subunit of NF-kappaB in the cytoplasm in conjunction with the down-regulation of NF-kappaB in the nucleus, suggesting that HDACIs blocked nuclear translocation of NF-kappaB. Based on these findings, we believe HDACIs can be useful for treating patients with ATL or other types of cancer in which NF-kappaB plays a role.

Topics: Antineoplastic Agents; Apoptosis; Benzamides; Blotting, Western; Cell Line; Cell Proliferation; Deltaretrovirus Infections; Electrophoretic Mobility Shift Assay; Enzyme Inhibitors; Flow Cytometry; Histone Deacetylase Inhibitors; Human T-lymphotropic virus 1; Humans; Hydroxamic Acids; Immunohistochemistry; Indoles; Leukemia-Lymphoma, Adult T-Cell; NF-kappa B; Panobinostat; Pyridines; Signal Transduction; Vorinostat