New Insights into the Development of Papillary Thyroid Cancer: The Roles of miR-1179 and ELF3

Thyroid cancer is the most prevalent endocrine malignancy, and papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer. Although the prognosis is generally favorable, a better understanding of the molecular mechanisms involved in this pathology could lead to new treatment opportunities. Dysregulation of miRNA expression has been correlated with tumor development, and miR-1179 has been previously identified as one of the most downregulated miRNAs in PTC. This study aimed to explore the role of miR-1179 in thyroid tumorigenesis. miR-1179 was overexpressed in the TPC-1, B-CPAP, and HTori-3 thyroid cell lines to characterize its function and identify mRNA targets. The relevance of our data for human PTC was then addressed by analyzing TCGA and independent PTC. We showed that miR-1179 triggered apoptosis and inhibited cell migration. We identified ELF3 as a direct target of miR-1179 and other effectors, including NOTCH3 and CX3CL1. Finally, we revealed the existence of an inverse correlation between decreased expression of miR-1179 and increased expression of ELF3, NOTCH3, and CX3CL1 mRNA in human PTC. Our findings suggest that miR-1179 is a tumor suppressor gene and that its loss may contribute to thyroid tumor progression by promoting the expression of ELF3, NOTCH3, and CX3CL1.