MicroRNA-203a-3p may prevent the development of thyroid papillary carcinoma via repressing MAP3K1 and activating autophagy.

ABSTRACT

BACKGROUND: Papillary thyroid carcinoma (PTC) grows slowly but has a great risk of metastasis. MicroRNAs are well known as vital tumor-related gene regulators. In PTC, the role of miR-203a-3p and the underlying mechanisms remain not completely understood. METHODS: We conducted CCK8 assay, wound healing assay, transwell experiment and flow cytometry analyses to investigate the function of miRNA-203a-3p. The interaction of miRNA-203a-3p with its gene MAP3K1 was characterized by quantitative real-time polymerase chain reaction, western blotting and luciferase assay. RESULTS: We found that the levels of miRNA-203a-3p were statistically decreased in PTC tissues. When mimics were delivered to TPC-1 and KTC-1 cells to upregulate miR-203a-3p, it was observed that cell proliferation, metastatic abilities and cell cycle process were prevented but cell apoptosis was enhanced. Furthermore, we proved the interaction between MAP3K1 and miR-203a-3p. Intriguingly, similar to miR-203a-3p mimics, siMAP3K1 showed a tumor-suppressive effect, and this effect could be reversed when miR-203a-3p was simultaneously inhibited. Finally, selected autophagy-linked proteins such as LC3 Beclin-1 were detected and found to be increased when miR-203a-3p was upregulated or MAP3K1 was inhibited. CONCLUSION: Overall, miR-203a-3p inhibits the oncogenic characteristics of TPC-1 and KTC-1 cells via suppressing MAP3K1 and activating autophagy. Our findings might enrich the understanding and the therapeutic strategies of PTC.