miR-144对甲状腺乳头状癌细胞增殖及细胞周期的影响

目的：研究甲状腺乳头状癌（PTC）细胞株中miR-144的表达水平，探讨miR-144不同表达水平对甲状腺癌细胞增殖能力及细胞周期的影响。方法：通过qPCR检测人PTC细胞K1、TPC-1和人甲状腺细胞Nthy-ori 3-1中miR-144的表达水平。K1细胞分别转染miR-144 mimics、miR-144 inhibitor及阴性对照（NC）。应用MTT增殖实验、克隆形成实验和流式细胞术分别检测miR-144不同表达水平对K1细胞生物学功能的影响。Western blot检测细胞周期蛋白Cyclin D1的表达情况。结果：PTC细胞中miR-144相对表达量与正常甲状腺细胞相比显著降低（P＜0.05），其中K1细胞中miR-144的表达量最低。在K1细胞株中过表达miR-144后，细胞的增殖能力、单克隆形成能力显著下降，并且Cyclin D1表达水平降低，细胞被阻滞在G0/G1期（P＜0.05）。而miR-144表达下调则得到相反的结果。结论：miR-144在PTC细胞中低表达。通过抑制PTC细胞增殖、阻滞细胞周期，miR-144可能在PTC的发生发展中扮演抑癌基因的角色。

The influence of miR-144 on cell proliferation and cell cycle of papillary thyroid carcinoma cells

Objective: To evaluate the expression levels of miR-144 in papillary thyroid carcinoma (PTC) cell lines. To explore the influence of up-regulation/down-regulation of miR-144 on cell proliferation and cell cycle in PTC cells. Methods: The expression levels of miR-144 in PTC cells K1, TPC-1 and human thyroid cells Nthy-ori 3-1 were detected by qPCR. K1 cells were transiently transfected with miR-144 mimics, inhibitor, or the negative control (NC) by Lipo2000. After transfection, MTT assay, colony formation assay and flow cytometry were conducted to explore the impact of miR-144 on cell proliferation ability and cell cycle of K1 cells. Western blot was provided to detect the protein expression of Cyclin D1. Results: Compared with thyroid cells, the relative expression levels of miR-144 in PTC cells were significantly decreased (P<0.05). The expression of miR-144 in K1 cells was lowest. The overexpression of miR-144 suppressed K1 cell proliferation and colony formation, caused K1 cells arrested in G0/G1 phase, which relate to downregulation of Cyclin D1. Whereas, low expression of miR-144 promoted cell proliferation, colony formation and accelerate the process of cell cycle.Conclusion: miR-144 was down-regulated in PTC cells. miR-144 may act as a tumor suppressor in PTC by inhibiting cell proliferation and blocking cell cycle, suggesting its use as a potential therapeutic target.