title: Inhibitors of histone deacetylases as potential therapeutic tools for high-risk embryonal tumors of the nervous system of childhood.
abstract: The origin of malignant embryonal tumors is incompletely understood and certain risk groups remain difficult to treat. The epigenetic structure of DNA and its lesions play a role in the origin of these neoplasms. Manipulation of the epigenome may offer novel treatment options. The authors evaluated the cytotoxicity of histone deacetylase inhibitors (HDI) [MS-275, SAHA, TSA, M344, M360, D85, SW55, SW187 and valproic acid (VPA)] on 13 embryonal tumor cell lines [4 medulloblastomas, 5 neuroblastomas, 2 atypical teratoid/rhabdoid tumors (AT/RT), and 2 malignant rhabdoid tumors of the kidney (RTK)] in MTT assay. In addition, HDI effects on hyperacetylation, reexpression of growth regulatory genes and apoptosis were characterized by Western analysis, RT-PCR and annexin-V staining. All HDI inhibited cell proliferation in a time- and dose-dependent manner. VPA was least cytotoxic with GI50 values after 72 hr ranging from 53.6 to 332.9 microM, while TSA was most efficient with GI50 values after 72 hr ranging from 0.01 to 8.8 microM. M344 and M360 were also highly effective. Western blot revealed hyperacetylation of histone H4 after HDI treatment. Reactivation of several genes including the proapoptotic CASP8 was identified by RT-PCR. Annexin-V staining demonstrated a dose and time dependent induction of apoptosis. HDI inhibited the growth of medulloblastoma, neuroblastoma and rhabdoid tumors in vitro. Treatment with HDI induced the reactivation of growth regulatory genes and consequently apoptosis. Our results warrant further studies and may help in the design of new protocols geared at the treatment of high risk embryonal tumors.
authors.affiliation: Department of Pediatric Hematology and Oncology, University Children's Hospital Muenster, Muenster, Germany.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Furchert
authors.forename: Claudia
authors.initials: C
authors.lastname: Lanvers-Kaminsky
authors.forename: Heribert
authors.initials: H
authors.lastname: Juürgens
authors.forename: Manfred
authors.initials: M
authors.lastname: Jung
authors.forename: Adele
authors.initials: A
authors.lastname: Loidl
authors.forename: Michael C
authors.initials: MC
authors.lastname: Frühwald
mesh_terms: D000107:Acetylation; D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D001932:Brain Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D056572:Histone Deacetylase Inhibitors; D006657:Histones / Q000378:metabolism; D006801:Humans; D008527:Medulloblastoma / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology*; D009447:Neuroblastoma / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D016133:Polymerase Chain Reaction; D018335:Rhabdoid Tumor / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D012307:Risk Factors; D014635:Valproic Acid / Q000494:pharmacology
chemical_list: D017304:Annexin A5; D004791:Enzyme Inhibitors; D056572:Histone Deacetylase Inhibitors; D006657:Histones; D014635:Valproic Acid