We have previously studied the function of microRNAs (miRNAs) in thyroid cells using the differentiated rat thyroid PC Cl 3 cells that need thyrotropin (TSH) for their growth. The miRNA expression profile examination allowed the detection of a set of miRNAs downregulated and upregulated by TSH. Here, we first demonstrated that upregulation of miR-130b-3p occurs through a protein kinase A-cAMP-responsive element binding protein (CREB)-dependent mechanism. Then, we analyzed its expression in human thyroid follicular adenomas, where a constitutive CREB activation is frequently present. miR-130b-3p results in upregulation with a high fold-change in most thyroid follicular adenomas. Then, we identified CCDC6, coding for a protein that interacts with CREB1 leading to the transcriptional repression of CREB1 target genes, as a target of this miRNA. The targeting of CCDC6 by miR-130b-3p likely accounts for the mechanism by which its upregulation contributes to the development of thyroid adenomas increasing CREB1 activity.
Keywords: Adenoma; Cell cycle; MicroRNA; Thyroid.