Open Access

ARTICLE

Upregulated miR-9-3p Promotes Cell Growth and Inhibits Apoptosis in Medullary Thyroid Carcinoma by Targeting BLCAP

by

Department of Otolaryngology Head and Neck Surgery, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi, P.R. China

Oncology Research 2017, 25(8), 1215-1222. https://doi.org/10.3727/096504016X14791715355957

Abstract

Medullary thyroid carcinoma (MTC) is a neuroendocrine cancer derived from parafollicular C cells in the thyroid gland. It has great interest as a research focus because of its unusual genetic, clinical, and prognostic characteristics. However, the pathogenesis in MTC is not completely clear. We investigated the role of miR- 9-3p and bladder cancer-associated protein (BLCAP) in MTC TT cells. First, miR-9-3p expression was upregulated in human MTC tissues and TT cells and compared to the control by RT-PCR. Flow cytometric analysis indicated that the cell cycle progression in TT cells was significantly inhibited by the miR-9-3p inhibitor but was increased by the miR-9-3p mimic. On the contrary, the apoptosis of TT cells was significantly increased by the miR-9-3p inhibitor and suppressed by the miR-9-3p mimic. A similar change pattern was observed in the expression of apoptosis-regulated protein caspase 3 induced by the miR-9-3p mimic or inhibitor in TT cells. We then identified that BLCAP is a target of miR-9-3p by bioinformatic prediction and luciferase reporter assay. The expression of BLCAP was also significantly downregulated by the miR-9-3p mimic while being upregulated by the miR-9-3p inhibitor in TT cells. Furthermore, we confirmed that the inhibited apoptosis of TT cells induced by the miR-9-3p mimic was enhanced by BLCAP overexpression. The levels of apoptosis were strongly decreased by BLCAP silencing in TT cells, which were not further influenced by the miR-9-3p inhibitor. In summary, upregulated miR-9-3p has a positive role in human MTC progression by regulating the growth and apoptosis of cancer cells via targeting BLCAP. This might represent a possible diagnosis or therapeutic target for MTC.

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