miR-217 inhibits proliferation, migration, and invasion via targeting AKT3 in thyroid cancer.

Purpose: The aims of this study were to test the influence of miR-217 on the proliferation, invasion, migration of thyroid cancer and the relevant mechanism.

Method: miR-217 expression levels in thyroid cancer tissues and cell lines were detected by quantitative real-time PCR (qRT-PCR).Cell Counting Kit-8, flow cytometer, wound healing, transwell invasion assays were applied to evaluate the effect of miR-217 on proliferation, apoptosis, migration and invasion of thyroid cells. The luciferase reporter assay, qRT-PCR, and western blot were used to identify target of miR-217. Relative relationship of expression level between miR-217 and AKT3 was analyzed in thyroid cancer tissues. Xenograft transplantation was performed to test effect of miR-217 in vivo.

Results: We found that the expression of miR-217 was significantly decreased in thyroid cancer tissues cell lines. Significantly, decreased miR-217 expression were associated with the clinical stage and lymph node metastasis. Function studies revealed that miR-217 overexpression in thyroid cancer cells inhibited proliferation, migration, and invasion in vitro, as well as suppressed tumor growth in vivo. Subsequently, AKT3 was identified as a target of miR-217 in thyroid cancer. AKT3 expression was upregulated in thyroid cancer tissues, was inversely correlated with miR-217expression. Besides, overexpression of AKT3 efficiently abrogates suppressive effect on proliferation, migration and invasion in thyroid cancer cells caused by overexpression of miR-217.

Conclusion: These data demonstrated a tumor suppressor role for miR-217 in thyroid cancer development and progression by targeting AKT3, suggesting miR-217 might be a potential target for thyroid cancer.