ABSTRACT
CONTEXT: Papillary thyroid carcinoma (PTC) is the most common thyroid malignancy. Dysregulated expression of miR-146b and androgen receptor (AR) has been shown to play critical roles in tumorigenesis in PTC. However, the mechanistic and clinical association between AR and miR-146b is not fully understood. OBJECTIVE: The purpose was to investigate miR-146b as the potential AR target miRNA and its involvement in advanced tumor characteristics of PTC. METHODS: Expression of AR and miR-146b were assessed in frozen and formalin-fixed paraffin-embedded tissue samples from PTC and adjacent normal thyroid specimens by quantitative real-time polymerase chain reaction, and their correlation was examined. Human thyroid cancer cell lines BCPAP and TPC-1 were used to evaluate the effect of AR on miR-146b signaling. Chromatin immunoprecipitation (ChIP) assays were performed to determine whether AR binds to the miR-146b promoter region. RESULTS: Pearson correlation analysis confirmed significant inverse correlation between miR-146b and AR expression. Overexpressing AR BCPAP and TPC-1 cells showed relatively lower miR-146b expression. ChIP assay revealed that AR might bind to the androgen receptor element located on the promoter region of miRNA-146b gene, and overexpression of AR suppresses miR-146b-mediated tumor aggressiveness. The low AR/high miR-146b PTC patient group was associated with advanced tumor characteristics, including higher tumor stage, lymph node metastasis, and worse treatment response. CONCLUSION: To sum up, miR-146b is a molecular target of AR transcriptional repression; therefore, AR suppresses miR-146b expression to reduce PTC tumor aggressiveness.
Subject(s)
Carcinoma, Papillary , MicroRNAs , Receptors, Androgen , Thyroid Cancer, Papillary , Thyroid Neoplasms , Humans , Androgens , Carcinoma, Papillary/genetics , Carcinoma, Papillary/metabolism , Cell Line, Tumor , Gene Expression Regulation, Neoplastic , MicroRNAs/metabolism , Receptors, Androgen/genetics , Receptors, Androgen/metabolism , Thyroid Cancer, Papillary/genetics , Thyroid Cancer, Papillary/pathology , Thyroid Neoplasms/genetics , Thyroid Neoplasms/pathologyABSTRACT
Papillary thyroid carcinomas (PTC), which is derived from thyroid follicular cells, is the most commonly differentiated thyroid cancer with sex disparity. However, the role of estrogen receptors (ERs) in the pathogenesis of PTC remains unclear. The present study aimed to determine the association of ER mRNA expression levels with clinicopathologic features in PTC. To that aim, the mRNA levels of ESR1 (ERα66), ESR1 (ERα36), ESR2, and G-protein-coupled estrogen receptor 1 (GPER1) in snap-frozen tissue samples from PTCs and adjacent normal thyroid tissues were determined using quantitative reverse transcription polymerase chain reaction (RT-qPCR), and the correlation between ER mRNA expression levels and clinicopathologic features was analyzed. The expression of ERα66, ERα36, ERß, and GPER1 was lower in PTC specimens than in adjacent normal thyroid tissues. Moreover, low GPER1 expression was associated with extrathyroidal extension. There was no obvious difference in expression of ERs between PTC specimens from male and female patients. In conclusion, our findings highlight the importance of ERs in PTC tumorigenesis.
Subject(s)
Estrogen Receptor alpha/genetics , Estrogen Receptor beta/genetics , Receptors, Estrogen/genetics , Receptors, G-Protein-Coupled/genetics , Thyroid Cancer, Papillary/pathology , Thyroid Neoplasms/pathology , Adult , Alternative Splicing , Cell Line, Tumor , Down-Regulation , Female , Gene Expression Regulation, Neoplastic , Humans , Male , Middle Aged , Neoplasm Staging , Prospective Studies , Thyroid Cancer, Papillary/genetics , Thyroid Neoplasms/geneticsABSTRACT
Male gender is a risk factor for mortality in patients with papillary thyroid carcinoma (PTC). This study investigated the impact of androgen receptor (AR) gene expression on the clinical features and progression of PTC. The levels of AR mRNA and protein in frozen, formalin-fixed, paraffin-embedded tissue samples from PTC and adjacent normal thyroid tissue were assessed by quantitative real-time polymerase chain reaction and immunohistochemical staining, respectively, and the relationships between AR expression and clinical features were analyzed. The thyroid cancer cell lines, BCPAP and TPC-1, were used to evaluate the effects of AR on the regulation of cell migration, and key epithelial-mesenchymal transition (EMT) markers. AR mRNA expression was significantly higher in normal thyroid tissue from men than women. The sex difference in AR mRNA expression diminished during PTC tumorigenesis, as AR mRNA expression levels were lower in PTC than normal thyroid tissues from both men and women. AR mRNA expression was significantly decreased in PTC patients with higher risk and in those with extrathyroidal extension. Overexpression of AR in BCPAP cells decreased cell migration and repressed the EMT process by down-regulating mRNA expression of N-cadherin, Snail1, Snail2, Vimentin, and TWIST1 and up-regulating E-cadherin gene expression. These results suggest that suppression of the androgen-AR axis may lead to aggressive tumor behavior in patients with PTC.
