MiR-26a inhibits thyroid cancer cell proliferation by targeting ARPP19.

miRNA, which involves in pathogenesis of thyroid cancer via different targets, has been found aberrantly expressed in thyroid cancer. Modes of actions of miR-26a in papillary thyroid carcinoma (PTC), however, have not been fully understood to this date. In vitro results obtained from this research confirmed miR-26a was down-regulated in PTC cells (i.e. TPC-1 and BCPAP) where the down-regulation of miR-26a was found to be able to promote cell proliferation. In order to explore the mechanisms, potential targets of miR-26a were postulated: cAMP regulated phosphoprotein 19 (ARPP19) turned out to be the target of miR-26a and it was by depleting ARPP19 was the cell proliferation be suppressed. This suggested that miR-26a regulated cell proliferation by targeting ARPP19. In addition, such a depletion of ARPP19 sensitized PTC cells to tamoxifen (TMX) treatment. The above findings indicated miR-26a was a target of interest regarding the treatment of refractory thyroid carcinomas.