title: Expression of the RET oncogene induces differentiation of SK-N-BE neuroblastoma cells.
abstract: Expression of the RET proto-oncogene, a cell surface receptor for an as yet unknown ligand, is associated with tumors, tissues, and cell lines of neural crest origin. Accumulating evidence suggests that RET activity is involved in the process of neuronal differentiation. Moreover, induction of phenotypic differentiation of neuroblastoma cell lines is associated with the rapid accumulation of RET transcripts. To verify the role of RET in neuronal differentiation, we introduced into the human neuroblastoma cell line SK-N-BE four versions of the RET oncogene, activated by different mechanisms: RET/PTC1 and RET/PTC3, which are activated by rearrangement with heterologous genes; and two activated RET mutants, which carry the single amino acid substitution found associated to the inheritance of the multiple endocrine neoplasia type 2A (retMEN2A allele) and type2B (retMEN2B allele), respectively. We demonstrate that, after transfection with the RET oncogenes, SK-N-BE cells display a reduced growth rate and acquire a neurite-bearing phenotype accompanied by enhanced expression of the axonal growth-associated protein, GAP-43, and the high molecular weight neurofilament, NF200. These results indicate that, when activated, RET is able to cause growth inhibition and to promote neuronal differentiation of neuroblastoma cells.
authors.affiliation: Endocrinology and Experimental Oncology Center, Consiglio Nazionale delle Ricerche, Italy.
authors.forename: A
authors.initials: A
authors.lastname: D'Alessio
authors.forename: G
authors.initials: G
authors.lastname: De Vita
authors.forename: G
authors.initials: G
authors.lastname: Calì
authors.forename: L
authors.initials: L
authors.lastname: Nitsch
authors.forename: A
authors.initials: A
authors.lastname: Fusco
authors.forename: G
authors.initials: G
authors.lastname: Vecchio
authors.forename: G
authors.initials: G
authors.lastname: Santelli
authors.forename: M
authors.initials: M
authors.lastname: Santoro
authors.forename: V
authors.initials: V
authors.lastname: de Franciscis
mesh_terms: D015152:Blotting, Northern; D002454:Cell Differentiation / Q000502:physiology; D002455:Cell Division / Q000502:physiology; D029721:Drosophila Proteins; D005455:Fluorescent Antibody Technique; D006801:Humans; D009154:Mutation / Q000502:physiology; D009447:Neuroblastoma; D009857:Oncogenes / Q000502:physiology*; D010641:Phenotype; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000502:physiology*; D051096:Proto-Oncogene Proteins c-ret; D012333:RNA, Messenger / Q000032:analysis; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000502:physiology*; D014212:Tretinoin / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000166:cytology / Q000502:physiology
chemical_list: D029721:Drosophila Proteins; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D014212:Tretinoin; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases; C416649:Ret protein, Drosophila