Inhibitors on Human Neuroblastoma (original) (raw)
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Molecular Cancer Therapeutics, 2007
All-trans retinoic acid (RA) causes differentiation of neuroblastoma cells, and retinoids have been used in clinical trials in children with advanced neuroblastoma. Combination of RA with histone deacetylase inhibitors (HDACi) could result in improved antitumorigenic activity. We have examined the effect of the HDACi trichostatin A (TSA), sodium butyrate, and suberoylanilide hydroxamic acid (SAHA), alone and in combination with RA in human neuroblastoma SH-SY5Y cells. At concentrations that cause sustained increase of histone H3 acetylation, HDACi produced extensive apoptotic cell death as shown by flow cytometry analysis and induction of poly(ADP-ribose) polymerase proteolysis. HDACi inhibited SH-SY5Y cell growth at a much larger extent than RA. This compound did not cause apoptosis and did not further increase HDACimediated cell death. In contrast, both types of drugs cooperated to inhibit cell growth, although synergistic effects were not found. In surviving cells, HDACi repressed cyclin D1 expression and increased the cyclin kinase inhibitors (CKI) p21 Waf1/Cip1 and p27 Kip1. Cyclin D1 was not affected by RA, but this retinoid also increased CKI levels. Induction of p21 Waf1/Cip1 and p27 Kip1 by HDACi was further enhanced in the presence of RA. This effect seems to be at least partially due to transcriptional stimulation of CKI gene expression because both types of drugs cooperated to increase CKI mRNA levels and to activate the CKI promoters in transient transfection assays. These results show the strong antitumorigenic effects of HDACi in neuroblastoma cells and reinforce the idea that combination therapy could be useful to inhibit tumor growth.
Cancer research, 2001
Histone deacetylase inhibitors (HDACIs) inhibit the growth of a variety of transformed cells in culture. We demonstrated previously that the hybrid-polar HDACI m-carboxycinnamic acid bis-hydroxamide (CBHA) induces apoptosis of human neuroblastoma in vitro and is effective in lower doses when combined with retinoids. The current study investigates the effect of CBHA on the growth of human neuroblastoma in vivo, both alone and in combination with all-trans retinoic acid (atRA), using a severe combined immunodeficiency-mouse xenograft model. CBHA (50, 100, and 200 mg/kg/day) inhibited growth of SMS-KCN-69n tumor xenografts in a dose-dependent fashion, with 200 mg/kg CBHA resulting in a complete suppression of tumor growth. The efficacy of 50 and 100 mg/kg CBHA was enhanced by the addition of 2.5 mg/kg atRA. This dose of atRA was ineffective when administered alone. Treatment was accompanied by mild weight loss in all groups except the lowest dose of CBHA. Our results suggest HDACIs alo...
Clinical Cancer Research, 2007
Histone acetylation is one of the main mechanisms involved in regulation of gene expression. During carcinogenesis, tumor-suppressor genes can be silenced by aberrant histone deacetylation. This epigenetic modification has become an important target for tumor therapy. The histone deacetylation inhibitor, suberoylanilide hydroxamic acid (SAHA), can induce growth arrest in transformed cells. The aim of this study is to examine the effects of SAHA on gene expression and growth of glioblastoma multiforme (GBM) cells in vitro and in vivo. Experimental Design: The effect of SAHA on growth of GBM cell lines and explants was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. Changes of the cell cycle and relative gene expression were detected by fluorescence-activated cell sorting, real-time reverse transcription-PCR, and Western blotting. After glioma cells were implanted in the brains of mice, the ability of SAHA to decrease tumor growth was studied. Results: Proliferation of GBM cell lines and explants were inhibited in vitro by SAHA (ED 50 , 2 Â 10 À6 to 2 Â 10 À5 mol/L, 5 days). SAHA exposure of human U87 and T98G glioma cell lines, DA66 and JM94 GBM explants, as well as a murine GL26 GBM cell line resulted in an increased accumulation of cells in G 2-M of the cell cycle. Many proapoptotic, antiproliferative genes increased in their expression (DR5, TNFa, p21 WAF1 , p27 KIP1), and many antiapoptotic, progrowth genes decreased in their levels (CDK2, CDK4, cyclin D1, cyclin D2) as measured by real-time reverse transcription-PCR and/or Western blot after these GBM cells were cultured with SAHA (2.5 Â 10 À6 mol/L, 1 day). Chromatin immunoprecipitation assay found that acetylation of histone 3 on the p21 WAF1 promoter was markedly increased by SAHA. In vivo murine experiments suggested that SAHA (10 mg/kg, i.v., or 100 mg/kg, i.p.) could cross the blood-brain barrier as shown by prominent increased levels of acetyl-H3 and acetyl-H4 in the brain tissue. Furthermore, the drug significantly (P < 0.05) inhibited the proliferation of the GL26 glioma cells growing in the brains of mice and increased their survival. Conclusions: Taken together, SAHA can slow the growth of GBM in vitro and intracranially in vivo. SAHA may be a welcome addition for the treatment of this devastating disease.
The efficacy of HDAC inhibitors in neoplasm treatment
2020
Introduction and purpose: Histone Deacetylases (HDACs) are associated with epigenetic regulation of gene expression. They are responsible of adequate action of not only histone proteins, but also crucial cell cycle proteins, such as p53, NF‐κB or alpha tubulin. Recent studies have shown the connection between expression of HDAC and carcinogenesis and impact of HDAC inhibitors on cancer therapy. The aim of the study was to review the recent studies on HDAC inhibitors efficiency in the treatment of hematologic neoplasms and solid tumors. It is a study review from 2010 to 2020 using the PubMed database and ClinicalTrials.gov.
Cell Death & Disease, 2015
For differentiation-defective malignancies, compounds that modulate transcription, such as retinoic acid and histone deacetylase (HDAC) inhibitors, are of particular interest. HDAC inhibitors are currently under investigation for the treatment of a broad spectrum of cancer diseases. However, one clinical drawback is class-specific toxicity of unselective inhibitors, limiting their full anticancer potential. Selective targeting of individual HDAC isozymes in defined tumor entities may therefore be an attractive alternative treatment approach. We have previously identified HDAC family member 8 (HDAC8) as a novel target in childhood neuroblastoma. Using small-molecule inhibitors, we now demonstrate that selective inhibition of HDAC8 exhibits antineuroblastoma activity without toxicity in two xenograft mouse models of MYCN oncogene-amplified neuroblastoma. In contrast, the unselective HDAC inhibitor vorinostat was more toxic in the same models. HDAC8-selective inhibition induced cell cycle arrest and differentiation in vitro and in vivo. Upon combination with retinoic acid, differentiation was significantly enhanced, as demonstrated by elongated neurofilament-positive neurites and upregulation of NTRK1. Additionally, MYCN oncogene expression was downregulated in vitro and tumor cell growth was markedly reduced in vivo. Mechanistic studies suggest that cAMP-response element-binding protein (CREB) links HDAC8-and retinoic acid-mediated gene transcription. In conclusion, HDAC-selective targeting can be effective in tumors exhibiting HDAC isozyme-dependent tumor growth in vivo and can be combined with differentiation-inducing agents.
2007
The retinoic acid receptor  (RAR) is a retinoic acid (RA)-inducible tumor suppressor, which plays an important role in the arrest of neuroblastoma cell growth. Using human neuroblastoma SH-SY5Y cells, we have examined the regulation of RAR expression by histone deacetylase inhibitors (HDACi), considered to be promising agents in anticancer therapy. Our results show that HDACi cooperated with RA to increase RAR mRNA levels and to activate the RAR2 promoter in transient transfection assays. Chromatin immunoprecipitation assays showed that the basal RAR2 promoter that contains the RA response element was refractory to acetylation by both HDACi and RA. In addition, HDACi caused a transient increase in acetylation of a downstream RAR2 region, even though global histones remain hyperacetylated after a prolonged treatment with the inhibitors. RA potentiated this response and maintained acetylation for a longer period. Despite the cooperation of RA with HDACi to increase transcription of the RAR gene, these inhibitors caused a paradoxical reduction of the cellular levels of the RAR protein in cells treated with the retinoid. This reduction is secondary to a change in the protein half-life that is decreased by the HDACi due to increased ubiquitin-independent proteasomal degradation. These results show that HDACi regulate expression of the tumor suppressor gene RAR by both transcriptional and posttranscriptional mechanisms and might then modulate sensitivity to the retinoid in neuroblastoma cells.
Molecular Endocrinology, 2007
The retinoic acid receptor  (RAR) is a retinoic acid (RA)-inducible tumor suppressor, which plays an important role in the arrest of neuroblastoma cell growth. Using human neuroblastoma SH-SY5Y cells, we have examined the regulation of RAR expression by histone deacetylase inhibitors (HDACi), considered to be promising agents in anticancer therapy. Our results show that HDACi cooperated with RA to increase RAR mRNA levels and to activate the RAR2 promoter in transient transfection assays. Chromatin immunoprecipitation assays showed that the basal RAR2 promoter that contains the RA response element was refractory to acetylation by both HDACi and RA. In addition, HDACi caused a transient increase in acetylation of a downstream RAR2 region, even though global histones remain hyperacetylated after a prolonged treatment with the inhibitors. RA potentiated this response and maintained acetylation for a longer period. Despite the cooperation of RA with HDACi to increase transcription of the RAR gene, these inhibitors caused a paradoxical reduction of the cellular levels of the RAR protein in cells treated with the retinoid. This reduction is secondary to a change in the protein half-life that is decreased by the HDACi due to increased ubiquitin-independent proteasomal degradation. These results show that HDACi regulate expression of the tumor suppressor gene RAR by both transcriptional and posttranscriptional mechanisms and might then modulate sensitivity to the retinoid in neuroblastoma cells.
DNA and histone deacetylases as targets for neuroblastoma treatment
Interdisciplinary Toxicology, 2010
Neuroblastoma, a tumor of the peripheral sympathetic nervous system, is the most frequent solid extra cranial tumor in children and is a major cause of death from neoplasia in infancy. Still little improvement in therapeutic options has been made, requiring a need for the development of new therapies. In our laboratory, we address still unsettled questions, which of mechanisms of action of DNA-damaging drugs both currently use for treatment of human neuroblastomas (doxorubicin, cis-platin, cyclophosphamide and etoposide) and another anticancer agent decreasing growth of neuroblastomas in vitro, ellipticine, are predominant mechanism(s) responsible for their antitumor action in neuroblastoma cell lines in vitro. Because hypoxia frequently occurs in tumors and strongly correlates with advanced disease and poor outcome caused by chemoresistance, the effects of hypoxia on efficiencies and mechanisms of actions of these drugs in neuroblastomas are also investigated. Since the epigenetic structure of DNA and its lesions play a role in the origin of human neuroblastomas, pharmaceutical manipulation of the epigenome may offer other treatment options also for neuroblastomas. Therefore, the effects of histone deacetylase inhibitors on growth of neuroblastoma and combination of these compounds with doxorubicin, cis-platin, etoposide and ellipticine as well as mechanisms of such effects in human neuroblastona cell lines in vitro are also investigated. Such a study will increase our knowledge to explain the proper function of these drugs on the molecular level, which should be utilized for the development of new therapies for neuroblastomas. KEY WORDS: neuroblastoma; DNA-damaging anticancer drugs; inhibitors of histone deacetylases; mechanisms of acticancer effects of drugs