Methylation levels of sodium-iodide symporter (NIS) promoter in benign and malignant thyroid tumors with reduced NIS expression

Autor(es)

Galrao, A. L. ^[1] ; Sodre, A. K. ^[1] ; Camargo, R. Y. ^[1] ; Friguglietti, C. U. ^[2] ; Kulcsar, M. A. ^[3] ; Lima, E. U. ^[1] ; Medeiros-Neto, G. ^[1] ; Rubio, I. G. S. ^[4]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Fac Med, LIM 25, Cellular & Mol Endocrine Lab, Thyroid Unit, Sao Paulo - Brazil

^[2] Santa Catarina Hosp, Sao Paulo - Brazil

^[3] ICESP, Sao Paulo - Brazil

^[4] Fed Univ Sao Paulo UNIFESP, Dept Biol Sci, BR-09972270 Diadema, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: ENDOCRINE; v. 43, n. 1, p. 225-229, FEB 2013.
• Citações Web of Science: 13

Resumo

DNA methylation regulates gene expression. Aberrant methylation plays an important role in human tumorigenesis. We have previously detected reduced NIS mRNA expression in thyroid tumors as compared to non-tumor tissues. Thus, in this study we investigated whether the methylation of the CpG-island located in the NIS gene promoter was associated with reduced mRNA expression in thyroid tumors. Methylation levels of 30 pairs of samples from 10 benign and 20 malignant thyroid tumors (T) along with matched non-tumor (NT) areas were determined by semiquantitative methylation specific-PCR. NIS methylation was detected in all samples. Methylation levels and frequencies did not differ between the groups and were not associated with BRAF mutational status. Highest methylation levels and frequencies were detected in the 5' region of the CpG-island decreasing toward the 3' end. Intraindividual analysis (T versus NT) showed high tumor methylation levels in 40 % of the samples in the benign group and 30 % in the malignant group, associated with low NIS mRNA expression. No quantitative correlation was detected between methylation levels and mRNA expression in any the groups. The results of this study showed that methylation of NIS promoter is a very frequent event in both benign and malignant tumors as well as in their surrounding tissues, and characterized a non-homogeneous methylation pattern along the CpG island. Therefore, further investigations involving other sites that may be implicated in methylation regulation of NIS expression are warranted. (AU)

• Processo FAPESP: 07/51236-3 - Metilacao do gene simportador sodio-iodo (nis) em tumores de tireoide.
• Beneficiário: Ana Luiza Resende Galrão
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 07/51235-7 - Metilacao do gene simportador sodio-iodo (nis) em tumores de tireoide.
• Beneficiário: Geraldo Antônio de Medeiros Neto
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 09/52517-1 - Metilação do gene simportador sódio-iodo (NIS) em tumores de tireoide
• Beneficiário: Ana Luiza Resende Galrão
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto