Objectives: To explore the molecular mechanism for thyroid cancer metastasis via analyzing the role of microRNA (miR)-21-5p and its target gene recombinant sclerostin domain containing protein 1 (SOSTDC1) in thyroid cancer.
Methods: The target miR-21-5p was screened through bioinformatics analysis and cell verification, and the thyroid cancer cell lines was transfected with miR-21-5p inhibitor. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) test, flow cytometry, and cell scratch test were used to detect the proliferation, apoptosis and migration of thyroid cancer cells in the miR-21-5p inhibitor group and the inhibitor control group, respectively. The luciferase report experiment was used to verify the relationship between miR-21-5p and SOSTDC1, Western blotting was used to detect the expression levels and phosphorylation levels of SOSTDC1,phosphatidylinositol 3 kinase (PI3K), protein kinase B (Akt) and mitogen-activated protein kinases (MAPK), extracellular regulated protein kinases (ERK) in thyroid cancer cells.
Results: MiR-21-5p was significantly increased in thyroid cancer cells,which was negatively correlated with SOSTDC1 (r=-0.24, P<0.01). The proliferation and migration of thyroid cancer cells in the miR-21-5p inhibitor group was significantly lower than that in the inhibitor control group (both P<0.01), and the apoptosis rate in the miR-21-5p inhibitor group was significantly higher than that in the inhibitor control group (P<0.01).The luciferase report experiment showed that miR-21-5p could target and regulate the expression level of SOSTDC1, and the expression of PI3K in the miR-21-5p inhibitor group was significantly lower than that in the inhibitor control group (P<0.01). There were no significant changes in Akt and ERK1/2 levels, but the phosphorylation levels of Akt and ERK1/2 in the miR-21-5p inhibitor group were significantly lower than those in the inhibitor control group (both P<0.01).
Conclusions: MiR-21-5p in thyroid cancer cells can target the expression of SOSTDC1 and affect the activities of PI3K/Akt and MAPK/ERK, thereby inhibiting the apoptosis of thyroid cancer cells and promoting cell proliferation and migration.
目的: 通过分析微RNA(microRNA，miR)-21-5p及其靶基因含硬化蛋白域蛋白1(recombinant sclerostin domain containing protein 1，SOSTDC1)在甲状腺癌中的作用，深入了解甲状腺癌转移的分子机制。方法: 通过生物信息学分析和细胞验证筛选出miR-21-5p，通过miR-21-5p 抑制剂转染甲状腺癌细胞系；采用MTT实验、流式细胞术和细胞划痕实验分别检测miR-21-5p抑制剂组和抑制剂对照组的甲状腺癌细胞增殖、凋亡和迁移的情况；采用荧光素酶报告实验验证miR-21-5p和SOSTDC1的靶向调控关系；采用蛋白质印迹法检测miR-21-5p抑制剂组和抑制剂对照组甲状腺癌细胞中SOSTDC1、下游磷脂酰肌醇3-激酶(phosphatidylinositol 3 kinase，PI3K)/蛋白激酶B(protein kinase B，Akt)和丝裂原活化蛋白激酶(mitogen-activated protein kinases，MAPK)/细胞外调节蛋白激酶(extracellular regulated protein kinases，ERK)信号通路因子的表达水平及磷酸化水平。结果: MiR-21-5p在甲状腺癌细胞中显著上升，且与SOSTDC1呈负相关(r=-0.24，P<0.01)；miR-21-5p抑制剂组甲状腺癌细胞增殖和迁移显著低于抑制剂对照组(均P<0.01)，细胞凋亡率显著高于抑制剂对照组(P<0.01)；荧光素酶报告实验表明miR-21-5p能够靶向调控SOSTDC1表达水平；甲状腺癌细胞中PI3K/Akt和MAPK/ERK信号通路检测显示miR-21-5p抑制剂组PI3K表达水平显著低于抑制剂对照组(P<0.01)，Akt和ERK1/2水平无显著变化，但miR-21-5p抑制剂组Akt和ERK1/2磷酸化水平显著低于抑制剂对照组(均P<0.01)。结论: 甲状腺癌细胞中miR-21-5p能够靶向抑制SOSTDC1的表达，影响PI3K/Akt和MAPK/ERK活性，从而抑制甲状腺癌细胞凋亡，促进细胞的增殖和迁移能力。.
Keywords: microRNA-21-5p; recombinant sclerostin domain containing protein 1; thyroid cancer.