title: Rewiring of the apoptotic TGF-β-SMAD/NFκB pathway through an oncogenic function of p27 in human papillary thyroid cancer.
abstract: Papillary thyroid carcinoma (PTC), the most frequent thyroid cancer, is characterized by low proliferation but no apoptosis, presenting frequent lymph-node metastasis. Papillary thyroid carcinoma overexpress transforming growth factor-beta (TGF-β). In human cells, TGF-β has two opposing actions: antitumoral through pro-apoptotic and cytostatic activities, and pro-tumoral promoting growth and metastasis. The switch converting TGF-β from a tumor-suppressor to tumor-promoter has not been identified. In the current study, we have quantified a parallel upregulation of TGF-β and nuclear p27, a CDK2 inhibitor, in samples from PTC. We established primary cultures from follicular epithelium in human homeostatic conditions (h7H medium). TGF-β-dependent cytostasis occurred in normal and cancer cells through p15/CDKN2B induction. However, TGF-β induced apoptosis in normal and benign but not in carcinoma cultures. In normal thyroid cells, TGF-β/SMAD repressed the p27/CDKN1B gene, activating CDK2-dependent SMAD3 phosphorylation to induce p50 NFκB-dependent BAX upregulation and apoptosis. In thyroid cancer cells, oncogene activation prevented TGF-β/SMAD-dependent p27 repression, and CDK2/SMAD3 phosphorylation, leading to p65 NFκB upregulation which repressed BAX, induced cyclin D1 and promoted TGF-β-dependent growth. In PTC samples from patients, upregulation of TGF-β, p27, p65 and cyclin D1 mRNA were significantly correlated, while the expression of the isoform BAX-β, exclusively transcribed in apoptotic cells, was negatively correlated. Additionally, combined ERK and p65 NFκB inhibitors reduced p27 expression and potentiated apoptosis in thyroid cancer cells while not affecting survival in normal thyroid cells. Our results therefore suggest that the oncoprotein p27 reorganizes the effects of TGF-β in thyroid cancer, explaining the slow proliferation but lack of apoptosis and metastatic behavior of PTC.
authors.affiliation: Centre for Investigations in Molecular Medicine and Chronic Disease (CIMUS) and Institute of Investigaciones Sanitarias (IDIS), Group of Endocrine Neoplasia and Differentiation, University of Santiago de Compostela (USC), Santiago de Compostela, Spain.
authors.forename: A R
authors.initials: AR
authors.lastname: Garcia-Rendueles
authors.affiliation: Centre for Investigations in Molecular Medicine and Chronic Disease (CIMUS) and Institute of Investigaciones Sanitarias (IDIS), Group of Endocrine Neoplasia and Differentiation, University of Santiago de Compostela (USC), Santiago de Compostela, Spain.
authors.forename: J S
authors.initials: JS
authors.lastname: Rodrigues
authors.affiliation: Centre for Investigations in Molecular Medicine and Chronic Disease (CIMUS) and Institute of Investigaciones Sanitarias (IDIS), Group of Endocrine Neoplasia and Differentiation, University of Santiago de Compostela (USC), Santiago de Compostela, Spain.
authors.forename: M E R
authors.initials: ME
authors.lastname: Garcia-Rendueles
authors.affiliation: Centre for Investigations in Molecular Medicine and Chronic Disease (CIMUS) and Institute of Investigaciones Sanitarias (IDIS), Group of Endocrine Neoplasia and Differentiation, University of Santiago de Compostela (USC), Santiago de Compostela, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Suarez-Fariña
authors.affiliation: Centre for Investigations in Molecular Medicine and Chronic Disease (CIMUS) and Institute of Investigaciones Sanitarias (IDIS), Group of Endocrine Neoplasia and Differentiation, University of Santiago de Compostela (USC), Santiago de Compostela, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Perez-Romero
authors.affiliation: Department of Surgery, University Hospital of Santiago de Compostela (CHUS) & University of Santiago de Compostela (USC), Santiago de Compostela, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Barreiro
authors.affiliation: Department of Endocrinology, University Hospital of Santiago de Compostela (CHUS) & University of Santiago de Compostela (USC), Santiago de Compostela, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Bernabeu
authors.affiliation: Department of Clinical Biochemistry, University Hospital of Santiago de Compostela (CHUS) & University of Santiago de Compostela (USC), Santiago de Compostela, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Rodriguez-Garcia
authors.affiliation: Endocrine Unit, Fondazione IRCCS Ca' Granda Policlinico, Milan, Italy.|Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Fugazzola
authors.affiliation: Department of Molecular-Targeting Cancer Prevention, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Sakai
authors.affiliation: Center for Advanced Biotechnology and Medicine, Susan Lehman Cullman Laboratory for Cancer Research, Ernest Mario School of Pharmacy, Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, NJ, USA.
authors.forename: F
authors.initials: F
authors.lastname: Liu
authors.affiliation: Department of Pathology, University Hospital of Santiago de Compostela (CHUS) & University of Santiago de Compostela (USC), Santiago de Compostela, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Cameselle-Teijeiro
authors.affiliation: Department of Proteomics, University Hospital of Santiago de Compostela (CHUS), Santiago de Compostela, Spain.
authors.forename: S B
authors.initials: SB
authors.lastname: Bravo
authors.affiliation: Centre for Investigations in Molecular Medicine and Chronic Disease (CIMUS) and Institute of Investigaciones Sanitarias (IDIS), Group of Endocrine Neoplasia and Differentiation, University of Santiago de Compostela (USC), Santiago de Compostela, Spain.
authors.forename: C V
authors.initials: CV
authors.lastname: Alvarez
mesh_terms: D017209:Apoptosis / Q000502:physiology; D002277:Carcinoma / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D002291:Carcinoma, Papillary; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D016328:NF-kappa B / Q000378:metabolism*; D015398:Signal Transduction; D051785:Smad Proteins / Q000378:metabolism*; D051900:Smad3 Protein / Q000378:metabolism; D051901:Smad4 Protein / Q000378:metabolism; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000378:metabolism*
chemical_list: C436291:CDKN1B protein, human; D016328:NF-kappa B; C497790:SMAD3 protein, human; C497796:SMAD4 protein, human; D051785:Smad Proteins; D051900:Smad3 Protein; D051901:Smad4 Protein; D016212:Transforming Growth Factor beta; D050760:Cyclin-Dependent Kinase Inhibitor p27