Abstract
Alice Augenlicht1, Manuel Saiselet1, Myriam Decaussin-Petrucci2, Guy Andry3, Jacques E. Dumont1 and Carine Maenhaut1
1 Institute of Interdisciplinary Research, Université libre de Bruxelles, Brussels, Belgium
2 Service d’Anatomie et Cytologie Pathologiques, Centre Hospitalier Lyon Sud, Université Lyon 1, Pierre Benite Cedex 69495, France
3 Surgery Department, J. Bordet Institute, Brussels 1000, Belgium
Correspondence to:
Carine Maenhaut, | email: | carine.maenhaut@ulb.be |
Keywords: miRNA; papillary thyroid carcinoma; IRS2; MAPK; PI3K
Received: December 15, 2020 Accepted: July 13, 2021 Published: August 03, 2021
ABSTRACT
The aberrant expression of miRNAs is often correlated to tumor development. MiR-7-5p is a recently discovered downregulated miRNA in thyroid papillary carcinoma (PTC). The goal of this project was to characterize its functional role in thyroid tumorigenesis and to identify the targeted modulated pathways. MiR-7-5p overexpression following transfection in TPC1 and HT-ori3 cells decreased proliferation of the two thyroid cell lines. Analysis of global transcriptome modifications showed that miR-7-5p inhibits thyroid cell proliferation by modulating the MAPK and PI3K signaling pathways which are both necessary for normal thyroid proliferation and play central roles in PTC tumorigenesis. Several effectors of these pathways are indeed targets of miR-7-5p, among which EGFR and IRS2, two upstream activators. We confirmed the upregulation of IRS2 and EGFR in human PTC and showed the existence of a negative correlation between the decreased expression of miR-7-5p and the increased expression of IRS2 or EGFR. Our results thus support a tumor-suppressor activity of miR-7-5p. The decreased expression of miR-7-5p during PTC tumorigenesis might give the cells a proliferative advantage and delivery of miR-7-5p may represent an innovative approach for therapy.