title: Inhibition of proliferation and induction of differentiation in medulloblastoma- and astrocytoma-derived cell lines with phenylacetate.
abstract: The authors investigated the effects of a nontoxic differentiation inducer, phenylacetate (PA), on neuroectodermal tumor-derived cell lines. Treatment of medulloblastoma (Daoy and D283 MED) and glioma (U-251MG, C6, and RG2) cell lines resulted in a dose-dependent decline in DNA synthesis and cell proliferation, associated with accumulation in the G0/G1 phase of the cell cycle. Phenylacetate decreased transforming growth factor (TGF)-beta 2 production by medulloblastoma Daoy cells. Neutralizing antibodies against either TGF beta 2 or TGF beta 1 failed to block the growth arrest observed. This suggests that, unlike other differentiation agents, such as retinoic acid, the effect of PA on medulloblastoma proliferation is not mediated by a TGF beta pathway. In addition to cytostasis, PA induced marked morphological changes in U-251MG and C6 glioma cells associated with increased abundance of glial fibrillary acidic protein-positive processes. Although the morphology of PA-treated medulloblastoma cells was not significantly altered, the D283 MED cells exhibited increased expression of neurofilament proteins and Hu antigen, indicative of differentiation along a neuronal pathway. The effects of PA on the medulloblastoma cell lines were compared to its effects on the human neuroblastoma cell line BE(2)C, which is capable of a bidirectional differentiation toward a neuronal or a glial/schwann cell pathway. In BE(2)C cells, PA induced differentiation toward a schwann/glial cell-like phenotype, suggesting that the choice of differentiation pathway is cell type and agent specific. These in vitro antiproliferative and differentiation inducing effects of PA suggest that this agent warrants further evaluation as a potential therapeutic modality for the treatment of medulloblastoma and malignant glioma in humans.
authors.affiliation: Cotzias Laboratory of Neuro-Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York, USA.
authors.forename: G
authors.initials: G
authors.lastname: Stockhammer
authors.forename: G T
authors.initials: GT
authors.lastname: Manley
authors.forename: R
authors.initials: R
authors.lastname: Johnson
authors.forename: M K
authors.initials: MK
authors.lastname: Rosenblum
authors.forename: D
authors.initials: D
authors.lastname: Samid
authors.forename: F S
authors.initials: FS
authors.lastname: Lieberman
mesh_terms: D000818:Animals; D001254:Astrocytoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D004273:DNA, Neoplasm / Q000096:biosynthesis / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D051959:ELAV Proteins; D016193:G1 Phase / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D005904:Glial Fibrillary Acidic Protein / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008527:Medulloblastoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D051379:Mice; D009419:Nerve Tissue Proteins; D009447:Neuroblastoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D016900:Neurofilament Proteins / Q000187:drug effects / Q000235:genetics; D009457:Neuroglia / Q000187:drug effects; D009474:Neurons / Q000187:drug effects; D010641:Phenotype; D010648:Phenylacetates / Q000008:administration & dosage / Q000494:pharmacology*; D016601:RNA-Binding Proteins / Q000187:drug effects / Q000235:genetics; D051381:Rats; D016192:Resting Phase, Cell Cycle / Q000187:drug effects; D012583:Schwann Cells / Q000187:drug effects; D016212:Transforming Growth Factor beta / Q000096:biosynthesis / Q000187:drug effects
chemical_list: D004273:DNA, Neoplasm; D051959:ELAV Proteins; D005904:Glial Fibrillary Acidic Protein; D009419:Nerve Tissue Proteins; D016900:Neurofilament Proteins; D010648:Phenylacetates; D016601:RNA-Binding Proteins; D016212:Transforming Growth Factor beta; C025136:phenylacetic acid