title: Glial cell line-derived neurotrophic factor induces proliferative inhibition of NT2/D1 cells through RET-mediated up-regulation of the cyclin-dependent kinase inhibitor p27(kip1).
abstract: Growth factors of the glial cell line-derived neurotrophic factor (GDNF) family control the differentiation of neuronal cells of the central and peripheral nervous systems. Intracellular signalling of these growth factors is, at least in part, mediated by activation of the RET receptor tyrosine kinase. Here, we demonstrate that GDNF triggering inhibits the proliferation of the embryonal carcinoma cell line NT2/D1. This anti-proliferative effect is accompanied by down-regulation of the SSEA-3 antigen, a marker typical of undifferentiated NT2/D1 cells. We show that these effects are mediated by activation of RET signalling. The block of RET by a kinase-deficient dominant negative mutant impairs GDNF-dependent growth inhibition, whereas the adoptive expression of a constitutively active RET, the RET-MEN2A oncogene, promotes effects similar to those exerted by GDNF. We show that RET signalling increases the expression of the cyclin-dependent kinase inhibitor p27(kip1) in NT2/D1 cells. Both DNA synthesis inhibition and SSEA-3 down-regulation are prevented if p27(kip1) expression is blocked by an antisense construct, which demonstrates that RET-triggered effects are mediated by p27(kip1).
authors.affiliation: Istituto Nazionale Tumori, via M. Semmola, 80131, Naples, Italy.
authors.forename: Gustavo
authors.initials: G
authors.lastname: Baldassarre
authors.forename: Paola
authors.initials: P
authors.lastname: Bruni
authors.forename: Angelo
authors.initials: A
authors.lastname: Boccia
authors.forename: Giuliana
authors.initials: G
authors.lastname: Salvatore
authors.forename: Rosa Marina
authors.initials: RM
authors.lastname: Melillo
authors.forename: Maria Letizia
authors.initials: ML
authors.lastname: Motti
authors.forename: Maria
authors.initials: M
authors.lastname: Napolitano
authors.forename: Barbara
authors.initials: B
authors.lastname: Belletti
authors.forename: Alfredo
authors.initials: A
authors.lastname: Fusco
authors.forename: Massimo
authors.initials: M
authors.lastname: Santoro
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Viglietto
mesh_terms: D000818:Animals; D015295:Antigens, Tumor-Associated, Carbohydrate; D018797:Cell Cycle Proteins / Q000096:biosynthesis*; D002454:Cell Differentiation; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D050760:Cyclin-Dependent Kinase Inhibitor p27; D029721:Drosophila Proteins; D004789:Enzyme Activation; D051100:Glial Cell Line-Derived Neurotrophic Factor; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D006028:Glycosphingolipids / Q000032:analysis; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins / Q000494:pharmacology*; D009474:Neurons / Q000502:physiology; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases / Q000502:physiology*; D055746:Stage-Specific Embryonic Antigens; D025521:Tumor Suppressor Proteins / Q000096:biosynthesis*; D015854:Up-Regulation
chemical_list: D015295:Antigens, Tumor-Associated, Carbohydrate; D018797:Cell Cycle Proteins; D029721:Drosophila Proteins; D051100:Glial Cell Line-Derived Neurotrophic Factor; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D006028:Glycosphingolipids; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D011518:Proto-Oncogene Proteins; D055746:Stage-Specific Embryonic Antigens; D025521:Tumor Suppressor Proteins; C052924:stage-specific embryonic antigen-3; D050760:Cyclin-Dependent Kinase Inhibitor p27; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases; C416649:Ret protein, Drosophila