miR-31 Reduces Cell Growth of Papillary Thyroid Carcinoma by RNA-Binding Protein HuR.

BACKGROUND: Increasing evidence suggests that microRNAs are widely involved in cancer progression and metastasis. However, the specific role of miR-31 in papillary thyroid carcinoma (PTC) is still largely unknown. METHODS: The level of miR-31 and HuR was detected in 30 pairedcancerous and noncancerous tissue samples using real time PCR. The impact of miR-31 on PTC cell viability and apoptosis was explored using MTT assay and flow cytometry, respectively. To explore the effect of miR-31 on HuR expression, luciferase reporter assay was used. RESULTS: In papillary thyroid carcinoma patients, miR-31 was significantly down regulated. Furthermore, down regulation of miR-31 increased the proliferation, migration, and invasion of ovarian carcinoma cells. Vice versa, over expression of miR-31 repressed cell invasion and viability. The luciferase reporter assay revealed that HuR was a target for miR-31. Further analysis defined that knockdown of HuR resulted in enhanced cell viability and decreased cell migration rate. CONCLUSIONS: Down regulation of miR-31 contributed to the malignant progression of papillary thyroid carcinoma cells by targeting HuR.