Expression of SMAD proteins, TGF-beta/activin signaling mediators, in human thyroid tissues / Expressão de proteínas SMAD, mediadores da sinalização de TGF-beta/activina, em tecidos de tiroide humana
Matsuo, Sílvia E; Fiore, Ana Paula Z. P; Siguematu, Simone M; Ebina, Kátia N; Friguglietti, Celso U. M; Ferro, Maria C; Kulcsar, Marco A. V; Kimura, Edna T.
Arq. bras. endocrinol. metab
; 54(4): 406-412, jun. 2010. ilus, graf, tab
Artículo
en Inglés
| LILACS | ID: lil-550710
OBJECTIVE:
To investigate the expression of SMAD proteins in human thyroid tissues since the inactivation of TGF-β/activin signaling components is reported in several types of cancer. Phosphorylated SMAD 2 and SMAD3 (pSMAD2/3) associated with the SMAD4 induce the signal transduction generated by TGF-β and activin, while SMAD7 inhibits this intracellular signaling. Although TGF-β and activin exert antiproliferative roles in thyroid follicular cells, thyroid tumors express high levels of these proteins. MATERIALS ANDMETHODS:
The protein expression of SMADs was evaluated in multinodular goiter, follicular adenoma, papillary and follicular carcinomas by immunohistochemistry.RESULTS:
The expression of pSMAD2/3, SMAD4 and SMAD7 was observed in both benign and malignant thyroid tumors. Although pSMAD2/3, SMAD4 and SMAD7 exhibited high cytoplasmic staining in carcinomas, the nuclear staining of pSMAD2/3 was not different between benign and malignant lesions.CONCLUSIONS:
The finding of SMADs expression in thyroid cells and the presence of pSMAD2/3 and SMAD4 proteins in the nucleus of tumor cells indicates propagation of TGF-β/activin signaling. However, the high expression of the inhibitory SMAD7, mostly in malignant tumors, could contribute to the attenuation of the SMADs antiproliferative signaling in thyroid carcinomas.
Biblioteca responsable:
BR1.1
Texto completo
Documentos relacionados