title: Genetic drivers of metastatic dissemination in sonic hedgehog medulloblastoma.
abstract: Leptomeningeal dissemination (LMD), the metastatic spread of tumor cells via the cerebrospinal fluid to the brain and spinal cord, is an ominous prognostic sign for patients with the pediatric brain tumor medulloblastoma. The need to reduce the risk of LMD has driven the development of aggressive treatment regimens, which cause disabling neurotoxic side effects in long-term survivors. Transposon-mediated mutagenesis studies in mice have revealed numerous candidate metastasis genes. Understanding how these genes drive LMD will require functional assessment using in vivo and cell culture models of medulloblastoma. We analyzed two genes that were sites of frequent transposon insertion and highly expressed in human medulloblastomas: Arnt (aryl hydrocarbon receptor nuclear translocator) and Gdi2 (GDP dissociation inhibitor 2). Here we show that ectopic expression of Arnt and Gdi2 promoted LMD in mice bearing Sonic hedgehog (Shh)-induced medulloblastomas. We overexpressed Arnt and Gdi2 in a human medulloblastoma cell line (DAOY) and an immortalized, nontransformed cell line derived from mouse granule neuron precursors (SHH-NPD) and quantified migration, invasiveness, and anchorage-independent growth, cell traits that are associated with metastatic competence in carcinomas. In SHH-NPD cells. Arnt and Gdi2 stimulated all three traits. In DAOY cells, Arnt had the same effects, but Gdi2 stimulated invasiveness only. These results support a mechanism whereby Arnt and Gdi2 cause cells to detach from the primary tumor mass by increasing cell motility and invasiveness. By conferring to tumor cells the ability to proliferate without surface attachment, Arnt and Gdi2 favor the formation of stable colonies of cells capable of seeding the leptomeninges.
authors: Noah C
authors: NC
authors: Jenkins
authors: Ricky R
authors: RR
authors: Kalra
authors: Adrian
authors: A
authors: Dubuc
authors: Walavan
authors: W
authors: Sivakumar
authors: Carolyn A
authors: CA
authors: Pedone
authors: Xiaochong
authors: X
authors: Wu
authors: Michael D
authors: MD
authors: Taylor
authors: Department of Neurosurgery, Clinical Neurosciences Center, University of Utah School of Medicine, 175 North Medical Drive East, Salt Lake City 84132, UT, USA. daniel.fults@hsc.utah.edu.
authors: Daniel W
authors: DW
authors: Fults
mesh_terms: D000818:Animals; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics; D002528:Cerebellar Neoplasms / Q000235:genetics* / Q000473:pathology*; D018014:Gene Transfer Techniques; D020730:Guanine Nucleotide Dissociation Inhibitors / Q000235:genetics / Q000378:metabolism; D053823:Hedgehog Proteins / Q000235:genetics*; D006801:Humans; D008527:Medulloblastoma / Q000235:genetics / Q000473:pathology / Q000556:secondary; D008577:Meningeal Neoplasms / Q000235:genetics / Q000556:secondary*; D051379:Mice; D008822:Mice, Transgenic; D016254:Mutagenesis, Insertional; D009154:Mutation / Q000235:genetics; D009362:Neoplasm Metastasis / Q000235:genetics; D059467:Transcriptome; D014410:Tumor Stem Cell Assay
chemical_list: C556293:GDI2 protein, human; D020730:Guanine Nucleotide Dissociation Inhibitors; D053823:Hedgehog Proteins; C509239:SHH protein, human; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator