Expression-based screening identifies the combination of histone deacetylase inhibitors and retinoids for neuroblastoma differentiation

Department of Pediatric Oncology, Dana-Farber Cancer Institute and Children's Hospital Boston, Harvard Medical School, Boston, MA 02115, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.81). 08/2008; 105(28):9751-6. DOI: 10.1073/pnas.0710413105
Source: PubMed

ABSTRACT The discovery of new small molecules and their testing in rational combination poses an ongoing problem for rare diseases, in particular, for pediatric cancers such as neuroblastoma. Despite maximal cytotoxic therapy with double autologous stem cell transplantation, outcome remains poor for children with high-stage disease. Because differentiation is aberrant in this malignancy, compounds that modulate transcription, such as histone deacetylase (HDAC) inhibitors, are of particular interest. However, as single agents, HDAC inhibitors have had limited efficacy. In the present study, we use an HDAC inhibitor as an enhancer to screen a small-molecule library for compounds inducing neuroblastoma maturation. To quantify differentiation, we use an enabling gene expression-based screening strategy. The top hit identified in the screen was all-trans-retinoic acid. Secondary assays confirmed greater neuroblastoma differentiation with the combination of an HDAC inhibitor and a retinoid versus either alone. Furthermore, effects of combination therapy were synergistic with respect to inhibition of cellular viability and induction of apoptosis. In a xenograft model of neuroblastoma, animals treated with combination therapy had the longest survival. This work suggests that testing of an HDAC inhibitor and retinoid in combination is warranted for children with neuroblastoma and demonstrates the success of a signature-based screening approach to prioritize compound combinations for testing in rare diseases.

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Available from: Renee D. Wright-Michaud, Jul 29, 2015
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    • "Efforts to establish a consensus on what constitutes the RA-induced differentiation has recently led to recognition of a set of 10 genes as a potential signature and a more general yet reliable predictor of differentiation in NBs (Hahn et al., 2008). Moreover, a gene-expression high-throughput screening of small molecule libraries revealed a synergistic action of RA (all trans RA and 13-cis RA) and histone deacetylase inhibitors towards induction of NB differentiation, both in culture and in vivo (Hahn et al., 2008). "
    Neuroblastoma - Present and Future, 02/2012; , ISBN: 978-953-307-016-2
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    • "We studied the effect of VPA on MAO A and its molecular mechanisms in a human neuronal BE(2)C cell line, which expresses MAO A (Chen et al., 2005) and well responds to VPA in terms of the activation of known VPA downstream target genes (Hahn et al., 2008). "
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    ABSTRACT: Valproic acid (VPA) has been widely used in clinics for the treatment of multiple neuropsychiatric disorders, such as epilepsy and bipolar disorder. One of the mechanisms by which VPA exerts its effect is through regulating the brain levels of serotonin. However, the molecular basis of this VPA action is not fully understood. Here, we report for the first time that VPA activates monoamine oxidase (MAO) A catalytic activity, mRNA level, and promoter activity. MAO A is a key enzyme that degrades a number of monoamine neurotransmitters, including serotonin. Our results show that VPA increased the phosphorylation of both Akt and Forkhead box O1 (FoxO1), whereas pretreatment of cells with 2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride (LY294002) (a phosphoinositide 3-kinase inhibitor) reduced the VPA activation of MAO A. Overexpression of FoxO1 dramatically repressed both the basal and VPA-induced MAO A catalytic and promoter activities to 30 to 60%. Small interfering RNA knockdown of FoxO1 attenuated the stimulating effect of VPA on MAO A. Moreover, introduction of a constitutively active form of FoxO1 abolished the activation of MAO A by VPA and Akt. These results suggest that FoxO1 is a repressor for MAO A transcription, and its phosphorylation is involved in VPA activation of MAO A. Sequence analysis, electrophoretic mobility shift and chromatin immunoprecipitation assays further showed the presence of a functional FoxO1-binding site in MAO A core promoter. Taken together, these results demonstrate that MAO A is a novel target for VPA via Akt/FoxO1 signaling pathway. This information provides new insights into the pharmacological mechanisms and therapeutic implications of VPA action.
    Molecular pharmacology 07/2011; 80(4):714-23. DOI:10.1124/mol.111.072744 · 4.12 Impact Factor
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    • "In another example, neuroblastoma cells differentiate in response to RA (Sidell et al., 1983; Turano et al., 2006; Muley et al., 2008); and, after completion of chemoradiotherapy, differentiation therapy with RA significantly improves survival in high risk neuroblastoma patients (Reynolds et al., 2003). More recently, differentiation therapy with RA plus histone deacetylase inhibitors, drugs which modify the epigenetic state of cells, was shown to be a powerful combination for neuroblastoma treatment (Hahn et al., 2008). An interaction of the zinc-finger protein Zfp423 (Gene ID: 94187) with the RXRα/RARα complex at RAREs was recently shown to be required for RA to induce cell proliferation arrest and differentiation of neuroblastoma cells (Huang et al., 2009). "
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    ABSTRACT: Retinoids are ubiquitous signaling molecules that influence nearly every cell type, exert profound effects on development, and complement cancer chemotherapeutic regimens. All-trans retinoic acid (RA) and other active retinoids are generated from vitamin A (retinol), but key aspects of the signaling pathways required to produce active retinoids remain unclear. Retinoids generated by one cell type can affect nearby cells, so retinoids also function in intercellular communication. RA induces differentiation primarily by binding to RARs, transcription factors that associate with RXRs and bind RAREs in the nucleus. Binding of RA: (1) initiates changes in interactions of RAR/RXRs with co-repressor and co-activator proteins, activating transcription of primary target genes; (2) alters interactions with proteins that induce epigenetic changes; (3) induces transcription of genes encoding transcription factors and signaling proteins that further modify gene expression (e.g., FOX03A, Hoxa1, Sox9, TRAIL, UBE2D3); and (4) results in alterations in estrogen receptor α signaling. Proteins that bind at or near RAREs include Sin3a, N-CoR1, PRAME, Trim24, NRIP1, Ajuba, Zfp423, and MN1/TEL. Interactions among retinoids, RARs/RXRs, and these proteins explain in part the powerful effects of retinoids on stem cell differentiation. Studies of this retinol signaling cascade enhance our ability to understand and regulate stem cell differentiation for therapeutic and scientific purposes. In cancer chemotherapeutic regimens retinoids can promote tumor cell differentiation and/or induce proteins that sensitize tumors to drug combinations. Mechanistic studies of retinoid signaling continue to suggest novel drug targets and will improve therapeutic strategies for cancer and other diseases, such as immune-mediated inflammatory diseases.
    Journal of Cellular Physiology 02/2011; 226(2):322-30. DOI:10.1002/jcp.22417 · 3.87 Impact Factor
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