panobinostat and Neuroblastoma

The molecular mechanisms and gene regulatory networks sustaining cell proliferation in neuroblastoma (NBL) cells are still not fully understood. In this tumor context, it has been proposed that anti-proliferative drugs, such as the pan-HDAC inhibitor panobinostat, could be tested to mitigate tumor progression. Here, we set out to investigate the effects of panobinostat treatment at the unprecedented resolution offered by single-cell sequencing. We identified a global senescence signature paired with reduction in proliferation in treated Kelly cells and more isolated transcriptional responses compatible with early neuronal differentiation. Using master regulator analysis, we identified BAZ1A, HCFC1, MAZ, and ZNF146 as the transcriptional regulators most significantly repressed by panobinostat. Experimental silencing of these transcription factors (TFs) confirmed their role in sustaining NBL cell proliferation in vitro.

Topics: Apoptosis; Chromosomal Proteins, Non-Histone; Humans; Hydroxamic Acids; Indoles; Neuroblastoma; Panobinostat

Development of new anticancer drugs with currently available animal models is hampered by the fact that human cancer cells are embedded in an animal-derived environment. Neuroblastoma is the most common extracranial solid malignancy of childhood. Major obstacles include managing chemotherapy-resistant relapses and resistance to induction therapy, leading to early death in very-high-risk patients. Here, we present a three-dimensional (3D) model for neuroblastoma composed of IMR-32 cells with amplified genes of the

Topics: Anaplastic Lymphoma Kinase; Antineoplastic Agents; Apoptosis; Cell Death; Cell Line; Cell Line, Tumor; Cell Proliferation; Fibroblasts; HEK293 Cells; Humans; Kidney; N-Myc Proto-Oncogene Protein; Neuroblastoma; Panobinostat; Tumor Microenvironment

We investigated whether targeting chromatin stability through a combination of the curaxin CBL0137 with the histone deacetylase (HDAC) inhibitor, panobinostat, constitutes an effective multimodal treatment for high-risk neuroblastoma.. The effects of the drug combination on cancer growth were examined. The combination of CBL0137 and panobinostat enhanced nucleosome destabilization, induced an IFN response, inhibited DNA damage repair, and synergistically suppressed cancer cell growth. Similar synergistic effects were observed when combining CBL0137 with other HDAC inhibitors. The CBL0137/panobinostat combination significantly delayed cancer progression in xenograft models of poor outcome high-risk neuroblastoma. Complete tumor regression was achieved in the transgenic Th-MYCN neuroblastoma model which was accompanied by induction of a type I IFN and immune response. Tumor transplantation experiments further confirmed that the presence of a competent adaptive immune system component allowed the exploitation of the full potential of the drug combination.. The combination of CBL0137 and panobinostat is effective and well-tolerated in preclinical models of aggressive high-risk neuroblastoma, warranting further preclinical and clinical investigation in other pediatric cancers. On the basis of its potential to boost IFN and immune responses in cancer models, the drug combination holds promising potential for addition to immunotherapies.

Topics: Animals; Carbazoles; Chromatin; Drug Combinations; Drug Evaluation, Preclinical; Histone Deacetylase Inhibitors; Mice; Neuroblastoma; Panobinostat; Tumor Cells, Cultured

Neuroblastoma commonly required multimodal therapy containing surgery, chemotherapy, radiotherapy, and immunotherapy.. In our case, who had refractory metastatic neuroblastoma, we use histone deacetylase inhibitor (panobinostat) in combination with chemotherapy agents and iodine-131-meta-iodobenzylguanidine (MIBG) therapy.. This approach leads to successfully treat the patient. MIBG scan and bone marrow examination after therapy revealed no evidence of tumor. Now, she underwent autologous transplantation six months ago and free of tumor.. Panobinostat can cause apoptosis induction in refractory metastatic neuroblastoma in combination with MIBG therapy and chemotherapy.

Topics: 3-Iodobenzylguanidine; Antineoplastic Combined Chemotherapy Protocols; Brain Neoplasms; Child; Combined Modality Therapy; Female; Histone Deacetylase Inhibitors; Humans; Iodine Radioisotopes; Neoplasms, Second Primary; Neuroblastoma; Panobinostat; Radiopharmaceuticals; Stem Cell Transplantation; Transplantation, Autologous; Treatment Outcome

Chromosome 17q gains are almost invariably present in high-risk neuroblastoma cases. Here, we perform an integrative epigenomics search for dosage-sensitive transcription factors on 17q marked by H3K27ac defined super-enhancers and identify TBX2 as top candidate gene. We show that TBX2 is a constituent of the recently established core regulatory circuitry in neuroblastoma with features of a cell identity transcription factor, driving proliferation through activation of p21-DREAM repressed FOXM1 target genes. Combined MYCN/TBX2 knockdown enforces cell growth arrest suggesting that TBX2 enhances MYCN sustained activation of FOXM1 targets. Targeting transcriptional addiction by combined CDK7 and BET bromodomain inhibition shows synergistic effects on cell viability with strong repressive effects on CRC gene expression and p53 pathway response as well as several genes implicated in transcriptional regulation. In conclusion, we provide insight into the role of the TBX2 CRC gene in transcriptional dependency of neuroblastoma cells warranting clinical trials using BET and CDK7 inhibitors.

Topics: Antineoplastic Agents; Azepines; Brain Neoplasms; Cell Line, Tumor; Cell Survival; Cyclin-Dependent Kinase-Activating Kinase; Cyclin-Dependent Kinases; DNA Copy Number Variations; Epigenesis, Genetic; Forkhead Box Protein M1; Gene Expression Regulation, Neoplastic; HEK293 Cells; Histones; Humans; Kv Channel-Interacting Proteins; N-Myc Proto-Oncogene Protein; Neuroblastoma; Organoids; Panobinostat; Phenylenediamines; Pyrimidines; Repressor Proteins; Signal Transduction; T-Box Domain Proteins; Triazoles; Tumor Suppressor Protein p53

Patients with neuroblastoma associated with MYCN oncogene amplification experience a very poor prognosis. BET bromodomain inhibitors are among the most promising novel anticancer agents as they block BRD3 and BRD4 from activating oncogene transcription. However, treatment with BET bromodomain inhibitors alone does not result in cancer remission in many murine models.. MYCN-amplified neuroblastoma cells were treated with vehicle control, the BET bromodomain inhibitor JQ1, the histone deacetylase inhibitor panobinostat, or the combination of JQ1 and panobinostat. Genes modulated by JQ1, panobinostat, or the combination therapy were identified by Affymetrix microarray, and cell proliferation and apoptosis were examined by Alamar blue assays and flow cytometry analysis. Modulation of LIN28B promoter activity by BRD3 and BRD4 was examined by chromatin immunoprecipitation and luciferase assays. In addition, neuroblastoma-bearing mice were treated with vehicle control, JQ1, and/or panobinostat.. LIN28B was one of the top genes synergistically reduced by JQ1 and panobinostat. BRD3 and BRD4 directly bound to the LIN28B gene promoter and activated LIN28B gene transcription, and knocking down LIN28B reduced the expression of N-Myc protein, but not N-Myc mRNA. JQ1 and panobinostat synergistically reduced LIN28B gene and N-Myc protein expression, and synergistically induced growth inhibition and apoptosis in neuroblastoma cells, but not normal nonmalignant cells in vitro In neuroblastoma-bearing mice, JQ1 and panobinostat synergistically and considerably reduced N-Myc protein expression in tumor tissues and blocked tumor progression.. Our findings have identified a novel strategy to reduce the N-Myc oncoprotein expression and a novel therapeutic approach for the treatment of aggressive neuroblastoma. Clin Cancer Res; 22(10); 2534-44. ©2016 AACR.

Topics: Animals; Antineoplastic Agents; Apoptosis; Azepines; Cell Line, Tumor; Cell Proliferation; Female; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Indoles; Mice; Mice, Inbred BALB C; Neuroblastoma; Nuclear Proteins; Oncogene Proteins; Panobinostat; Promoter Regions, Genetic; Proteins; Proto-Oncogene Proteins c-myc; Transcription, Genetic; Triazoles; Xenograft Model Antitumor Assays

Neuroblastoma is the most common extra-cranial malignancy in childhood and accounts for ∼15% of childhood cancer deaths. Amplification of MYCN in neuroblastoma is associated with aggressive disease and predicts for poor prognosis. Novel therapeutic approaches are therefore essential to improving patient outcomes in this setting. The histone deacetylases are known to interact with N-Myc and regulate numerous cellular processes via epigenetic modulation, including differentiation. In this study, we used the TH-MYCN mouse model of neuroblastoma to investigate the antitumor activity of the pan-HDAC inhibitor, panobinostat. In particular we sought to explore the impact of long term, continuous panobinostat exposure on the epigenetically driven differentiation process. Continuous treatment of tumor bearing TH-MYCN transgenic mice with panobinostat for nine weeks led to a significant improvement in survival as compared with mice treated with panobinostat for a three-week period. Panobinostat induced rapid tumor regression with no regrowth observed following a nine-week treatment period. Initial tumor response was associated with apoptosis mediated via upregulation of BMF and BIM. The process of terminal differentiation of neuroblastoma into benign ganglioneuroma, with a characteristic increase in S100 expression and reduction of N-Myc expression, occurred following prolonged exposure to the drug. RNA-sequencing analysis of tumors from treated animals confirmed significant upregulation of gene pathways associated with apoptosis and differentiation. Together our data demonstrate the potential of panobinostat as a novel therapeutic strategy for high-risk neuroblastoma patients.

Topics: Animals; Apoptosis; Cell Differentiation; Cell Line, Tumor; Cell Proliferation; Disease Models, Animal; Female; Gene Expression Regulation, Neoplastic; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Indoles; Male; Mice; Mice, Transgenic; Neuroblastoma; Panobinostat; Proto-Oncogene Proteins c-myc; S100 Proteins; Survival Analysis

Despite advances in treatment regimens, patients with high-risk neuroblastoma have long-term survival rates of < 40%. Wee1 inhibition in combination with CHK1 inhibition has shown promising results in neuroblastoma cells. In addition, it has been demonstrated that panobinostat can downregulate CHK1. Therefore, combination of panobinostat and MK-1775 may result in synergistic cytotoxicity against neuroblastoma cell lines.. In vitro cytotoxicities of panobinostat and MK-1775 at clinically achievable concentrations, either alone or in combination, were evaluated in SK-N-AS, SK-N-DZ, and SK-N-BE(2) high-risk neuroblastoma cell lines using MTT assays. The mechanism of antitumor interaction was investigated using propidium iodide (PI) staining and flow cytometry analysis to determine apoptosis, as well as Western blotting to assess expression of phosphorylated CDK1/2, CHK1, and H2AX.. Treatment of neuroblastoma cell lines with 500 nM MK-1775 caused growth arrest and apoptosis in SK-N-DZ and SK-N-AS, while it had minimal effect on the SK-N-BE(2) cell line. The combination of panobinostat and MK-1775 resulted in synergistic antitumor interactions in all three of the cell lines tested. MK-1775 treatment in SK-N-BE(2) cells induced increased levels of p-CHK1(S345) , which could be decreased by the addition of panobinostat. This was accompanied by increased DNA damage and apoptosis.. The combination of panobinostat and MK-1775 has synergistic antitumor activity against neuroblastoma cell lines and holds promise as a potential treatment strategy for the management of high-risk neuroblastoma patients.

Topics: Apoptosis; Blotting, Western; Cell Cycle; Cell Cycle Proteins; Cell Proliferation; Drug Synergism; Drug Therapy, Combination; Histone Deacetylase Inhibitors; Histone Deacetylases; Humans; Hydroxamic Acids; Indoles; Neuroblastoma; Nuclear Proteins; Panobinostat; Protein-Tyrosine Kinases; Pyrazoles; Pyrimidines; Pyrimidinones; Risk Factors; Tumor Cells, Cultured

Neuroblastoma is an embryonic solid tumor of neural crest origin and accounts for 11% of all cancer-related deaths in children. Novel therapeutic strategies are therefore urgently required. MYCN oncogene amplification, which occurs in 20% of neuroblastomas, is a hallmark of high risk. Here, we aimed to exploit molecular mechanisms that can be pharmacologically addressed with epigenetically modifying drugs, such as histone deacetylase (HDAC) inhibitors. Grainyhead-like 1 (GRHL1), a gene critical for Drosophila neural development, belonged to the genes most strongly responding to HDAC inhibitor treatment of neuroblastoma cells in a genome-wide screen. An increase in the histone H4 pan-acetylation associated with its promoter preceded transcriptional activation. Physically adjacent, HDAC3 and MYCN colocalized to the GRHL1 promoter and repressed its transcription. High-level GRHL1 expression in primary neuroblastomas correlated on transcriptional and translational levels with favorable patient survival and established clinical and molecular markers for favorable tumor biology, including lack of MYCN amplification. Enforced GRHL1 expression in MYCN-amplified neuroblastoma cells with low endogenous GRHL1 levels abrogated anchorage-independent colony formation, inhibited proliferation, and retarded xenograft growth in mice. GRHL1 knockdown in MYCN single-copy cells with high endogenous GRHL1 levels promoted colony formation. GRHL1 regulated 170 genes genome-wide, and most were involved in pathways regulated during neuroblastomagenesis, including nervous system development, proliferation, cell-cell adhesion, cell spreading, and cellular differentiation. In summary, the data presented here indicate a significant role of HDAC3 in the MYCN-mediated repression of GRHL1 and suggest drugs that block HDAC3 activity and suppress MYCN expression as promising candidates for novel treatment strategies of high-risk neuroblastoma.

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Cell Proliferation; Disease-Free Survival; Female; Gene Expression Regulation, Neoplastic; Gene Silencing; Genes, Tumor Suppressor; Histone Deacetylase Inhibitors; Histone Deacetylases; Humans; Hydroxamic Acids; Indoles; Infant; Kaplan-Meier Estimate; Mice; Mice, SCID; N-Myc Proto-Oncogene Protein; Neoplasm Transplantation; Neuroblastoma; Nuclear Proteins; Oncogene Proteins; Panobinostat; Repressor Proteins; Transcription, Genetic; Tumor Burden

High-risk neuroblastoma remains a therapeutic challenge with a long-term survival rate of less than 40%. Therefore, new agents are urgently needed to overcome chemotherapy resistance so as to improve the treatment outcome of this deadly disease. Histone deacetylase (HDAC) inhibitors (HDACIs) represent a novel class of anticancer drugs. Recent studies demonstrated that HDACIs can down-regulate the CHK1 pathway by which cancer cells can develop resistance to conventional chemotherapy drugs. This prompted our hypothesis that combining HDACIs with DNA damaging chemotherapeutic drugs for treating neuroblastoma would result in enhanced anti-tumor activities of these drugs. Treatment of high-risk neuroblastoma cell lines with a novel pan-HDACI, panobinostat (LBH589), resulted in dose-dependent growth arrest and apoptosis in 4 high-risk neuroblastoma cell lines. Further, the combination of panobinostat with cisplatin, doxorubicin, or etoposide resulted in highly synergistic antitumor interactions in the high-risk neuroblastoma cell lines, independent of the sequence of drug administration. This was accompanied by cooperative induction of apoptosis. Furthermore, panobinostat treatment resulted in substantial down-regulation of CHK1 and its downstream pathway and abrogation of the G2 cell cycle checkpoint. Synergistic antitumor interactions were also observed when the DNA damaging agents were combined with a CHK1-specific inhibitor, LY2603618. Contrary to panobinostat treatment, LY2603618 treatments neither resulted in abrogation of the G2 cell cycle checkpoint nor enhanced cisplatin, doxorubicin, or etoposide-induced apoptosis in the high-risk neuroblastoma cells. Surprisingly, LY2603618 treatments caused substantial down-regulation of total CDK1. Despite this discrepancy between panobinostat and LY2603618, our results indicate that suppression of the CHK1 pathway by panobinostat is at least partially responsible for the synergistic antitumor interactions between panobinostat and the DNA damaging agents in high-risk neuroblastoma cells. The results of this study provide a rationale for clinical evaluation of the combination of panobinostat and cisplatin, doxorubicin, or etoposide for treating children with high-risk neuroblastoma.

Topics: Antineoplastic Agents; Apoptosis; Blotting, Western; Cell Line, Tumor; Cell Proliferation; Checkpoint Kinase 1; Cisplatin; Dose-Response Relationship, Drug; Doxorubicin; Drug Synergism; Etoposide; G2 Phase Cell Cycle Checkpoints; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Indoles; Neuroblastoma; Panobinostat; Phenylurea Compounds; Protein Kinases; Pyrazines