Up-regulation of miR-340-5p promotes progression of thyroid cancer by inhibiting BMP4.

Abstract

The incidence of thyroid cancer is increasing and the proliferation of thyroid cancer cells is incompletely understood. microRNAs may play key roles in thyroid cancer progression. We analyzed miR-340-5p in thyroid cancer tissue and normal tissue, and using informatics to predict its target. Cell lines and a mouse model were used to study the role of miR-340-5p in cancer proliferation. Overexpression of miR-340-5p was found in thyroid cancer specimens. Tumors with higher pathological grade had higher levels of miR-340-5p. Overexpression of miR-340-5p significantly enhanced cell viability and colony formation. Treatment of anti-miR-340-5p, however, showed opposite alterations. We predicted that bone morphogenetic protein 4 (BMP4) is a possible target, and found a negative correlation between miR-340-5p and BMP4 levels in thyroid cancer tissue. miR-340-5p reduced BMP4 expression. BMP4 overexpression attenuated the effects of miR-340-5p in cell viability and colony formation. In addition, using a xenograft mouse model we proved that anti-miR-340-5p was able to inhibit tumor growth. miR-340-5p promotes thyroid cancer proliferation by inhibiting BMP4. Anti-miR-340-5p can be a promising strategy to control thyroid cancer.