The Role Of MicroRNA In Papillary Thyroid Carcinoma

Objective:To explore the roles of microRNA in the papillary thyroid carcinoma.Methods:(1) Total RNA was extracted from 13 PTC tissues,13 FA tissues,13 normal thyroid tissues, and the expressions of miRNAs were examined using miRNA microarray chip. The most significant changed miRNAs from microarray were verified by qPCR. (2) Quantitative PCR was used to detect and compare the expression of microRNA-21 in 12 pairs of PTC and normal thyroid tissue. The expression of miR-21 in K1 cell was down-regulated by Anti-miR-21 and mimic-miR-21 transient transfection with Lipofectamine2000, and the effect was identified by real-time quantitative PCR. Cell proliferation after transfection with anti-miR-21 was analyzed using MTT assay. The cell apoptosis was analyzed by flow cytometry. Western blotting was employed to test the expressions of Bcl-2, Bax protein in Kl cell. Results:(1) Microarray chip analysis indicated that miR-222, miR-221, miR-146b-5p, miR-21 were overexpressed and miR-26b was underexpressed in PTC, miR-222、miR-221、miR-140-3p、miR-3613-3p were overexpressed and miR-26b was underexpressed in FA. (p<0.01)Among of them, the most significant up regulation of miRNAs (miR-222, miR-221, miR-146b-5p, miR-21) and down regulation (miR-26b) of miRNAs were further verified with qRT-PCR. The result showed that miR-146b-5p was significant different between PTC and follicular adenoma tissues (p<0.01). (2) Compared with adjacent normal tissue, miR-21 in PTC was significantly up-regulated(P<0.05), The miR-21 expression of K1 cell was significantly down-regulated 24 hours after Anti-miR-21 transfection(P<0.01),Suppression of miR-21 expression significantly reduced the proliferation (P<0.05) and increased the apoptosis rate to19.5%,compared with the negative control(Anti-miR-NC) group 9.4%.The expressions of Bcl-2 were down-regulated and that of Bax was up-regulated in the anti-miR-21 treated K1 cells as compared with the negative control(Anti-miR-NC) group. Conclusion:(1) Some miRNAs expressed differently between PTC、follicular adenoma and control groups, particularly miR-146b-5p, might potentially be adjunct markers for diagnosing papillary thyroid carcinoma.(2) The expression of miR-21 is up-regulated in PTC. Down-regulating expression of miR-21 significantly inhibits proliferation while promotes apoptosis of K1 cell.