title: Bone morphogenetic protein-7 is a MYC target with prosurvival functions in childhood medulloblastoma.
abstract: Medulloblastoma (MB) is the most common malignant brain tumor in children. It is known that overexpression and/or amplification of the MYC oncogene is associated with poor clinical outcome, but the molecular mechanisms and the MYC downstream effectors in MB remain still elusive. Besides contributing to elucidate how progression of MB takes place, most importantly, the identification of novel MYC-target genes will suggest novel candidates for targeted therapy in MB. A group of 209 MYC-responsive genes was obtained from a complementary DNA microarray analysis of a MB-derived cell line, following MYC overexpression and silencing. Among the MYC-responsive genes, we identified the members of the bone morphogenetic protein (BMP) signaling pathway, which have a crucial role during the development of the cerebellum. In particular, the gene BMP7 was identified as a direct target of MYC. A positive correlation between MYC and BMP7 expression was documented by analyzing two distinct sets of primary MB samples. Functional studies in vitro using a small-molecule inhibitor of the BMP/SMAD signaling pathway reproduced the effect of the small interfering RNA-mediated silencing of BMP7. Both approaches led to a block of proliferation in a panel of MB cells and to inhibition of SMAD phosphorylation. Altogether, our findings indicate that high MYC levels drive BMP7 overexpression, promoting cell survival in MB cells. This observation suggests the potential relevance of targeting the BMP/SMAD pathway as a novel therapeutic approach for the treatment of childhood MB.
authors.affiliation: Department of Oncology, University Children's Hospital, Zurich, Switzerland.
authors.forename: G
authors.initials: G
authors.lastname: Fiaschetti
authors.forename: D
authors.initials: D
authors.lastname: Castelletti
authors.forename: S
authors.initials: S
authors.lastname: Zoller
authors.forename: A
authors.initials: A
authors.lastname: Schramm
authors.forename: C
authors.initials: C
authors.lastname: Schroeder
authors.forename: M
authors.initials: M
authors.lastname: Nagaishi
authors.forename: D
authors.initials: D
authors.lastname: Stearns
authors.forename: M
authors.initials: M
authors.lastname: Mittelbronn
authors.forename: A
authors.initials: A
authors.lastname: Eggert
authors.forename: F
authors.initials: F
authors.lastname: Westermann
authors.forename: H
authors.initials: H
authors.lastname: Ohgaki
authors.forename: T
authors.initials: T
authors.lastname: Shalaby
authors.forename: M
authors.initials: M
authors.lastname: Pruschy
authors.forename: A
authors.initials: A
authors.lastname: Arcaro
authors.forename: M A
authors.initials: MA
authors.lastname: Grotzer
mesh_terms: D015153:Blotting, Western; D055419:Bone Morphogenetic Protein 7 / Q000235:genetics*; D002470:Cell Survival / Q000235:genetics*; D002528:Cerebellar Neoplasms / Q000235:genetics* / Q000473:pathology; D002648:Child; D004797:Enzyme-Linked Immunosorbent Assay; D020868:Gene Silencing; D016259:Genes, myc; D006801:Humans; D008527:Medulloblastoma / Q000235:genetics* / Q000473:pathology; D010766:Phosphorylation; D051785:Smad Proteins / Q000378:metabolism
chemical_list: C525819:BMP7 protein, human; D055419:Bone Morphogenetic Protein 7; D051785:Smad Proteins