Abstract:

Objective To explore the expression of microRNA ⁃7⁃5p（miR ⁃7⁃5p）in papillary thyroid carcinoma（PTC）tissues，para⁃carcinoma，as well as cell lines and its influenceon the proliferation，invasion and migration of PTC cells and its related molecular mechanism. Methods Quantitative Real⁃Time PCR（qRT⁃PCR） was used to detect the expression of miR⁃7⁃5p in 52 cases of PTC，para⁃carcinoma and human PTC cell lines TPC⁃1， BCPAP，K1 and human normal thyroid follicular cell line Nthy⁃ori 3⁃1，respectively. MiR⁃7⁃5p mimics and mimics ⁃NC were transfected into TPC⁃1 cells and K1cells with LipofectaminTM 3000 and divided into blank control group，negative control group（mimics⁃NC/NC⁃in group）and experimental group（mimics⁃7⁃5p/inhibitor⁃7⁃5p group）. The proliferation，invasion and migration abilities of cells in 3 groups were tested by growth curve，transwell invasion and scratch. The binding of miR ⁃7⁃5p to the TFF3⁃3′UTR was detected by dual luciferase reporter gene experi⁃ ment，and effect of miR⁃7⁃5p on TFF3 expression by western blot. Results The expression of miR⁃7⁃5p in PTC and the 3 PTC cell lines was significantly lower than that in adjacent tissues and Nthy⁃ori 3⁃1 cell（P < 0.01）. Mir⁃ 7⁃5p expression was significantly different in PTC patients with different clinical stages，tumor size and lymph node metastasis（P < 0.01）. After the up⁃regulation of miR⁃7⁃5p，the proliferation，invasion and migration abilities of TPC⁃1 and K1cells decreased significantly（P < 0.05）. The double luciferase reporter gene experiment showed that the luciferase activity value in mimics⁃7⁃5p/inhibitor⁃7⁃5p group was lower/or higher when compared that in the control group（P < 0.01）. Conclusion The expression of miR⁃7⁃5p is low in PTC tissues，and miR⁃7⁃5p can inhibit the proliferation，invasion and migration of PTC cells by targeting TFF3.

Key words:

miR?7?5p, papillary thyroid carcinoma, trefoil factor 3（TFF3）