miR-551b在甲状腺癌中的表达及对SW579细胞增殖和凋亡的影响

Expression of miR-551b in thyroid cancer and its effects on SW579 cell proliferation and apoptosis

目的探讨微小RNA(miR)-551b在甲状腺癌中的表达及对SW579细胞增殖、凋亡的影响。方法收集2017年10月至2019年10月本院获得的28例甲状腺癌组织及其癌旁正常组织标本,实时荧光定量PCR(qRT-PCR)法检测miR-551b在甲状腺癌组织及癌旁正常组织中的表达情况。体外培养甲状腺癌细胞SW579,分为对照组(不转染)、siRNA NC组(转染nonsense siRNA)、miR-551b siRNA组(转染miR-551b siRNA)、mimic NC组(转染negative control-miR-551b)和miR-551b mimic组(转染hsa-miR-551b mimic)。qRT-PCR法检测各组SW579细胞中miR-551b表达情况。CCK-8法检测各组SW579细胞增殖情况。流式细胞仪检测各组SW579细胞凋亡情况及其细胞周期分布情况。蛋白印迹法检测各组SW579细胞中增殖细胞核抗原(PCNA)、Bcl-2相关X蛋白(Bax)、细胞周期蛋白D1(Cyclin D1)蛋白表达情况。结果甲状腺癌组织中miR-551b表达水平较癌旁正常组织显著降低(P<0.05)。与siRNA NC组相比,miR-551b siRNA组SW579细胞中miR-551b水平、细胞凋亡率、G 0/G 1期细胞比例及Bax蛋白水平显著降低(P<0.05),细胞OD值、S期、G2/M期细胞比例及PCNA、Cyclin D1蛋白水平显著升高(P<0.05)。与mimic NC组相比,miR-551b mimic组SW579细胞中miR-551b水平、细胞凋亡率、G 0/G 1期细胞比例及Bax蛋白水平显著升高(P<0.05),细胞OD值、S期、G2/M期细胞比例及PCNA、Cyclin D1蛋白水平显著降低(P<0.05)。结论miR-551b在甲状腺癌组织中表达下调,可抑制癌细胞增殖并诱导其凋亡,可能与甲状腺癌发生发展密切相关。

Objective To investigate the expression of microRNA(miR)-551b in thyroid cancer and its effects on cell proliferation and apoptosis.Methods From October 2017 to October 2019,28 cases of thyroid cancer tissues and precancerous normal tissues were collected,and the expression of miR-551b in thyroid cancer tissues and precancerous normal tissues was detected by real-time fluorescence quantitative PCR(qRT-PCR).The thyroid cancer SW579 cells were cultured in vitro,and then divided into control group(no transfection),siRNA NC group(transfected with nonsense siRNA),miR-551b siRNA group(transfected with miR-551b siRNA),mimic NC group(transfected with negative control-miR-551b)and miR-551b mimic group(transfected with hsa-miR-551b mimic).Then the expression of miR-551b in SW579 cells was detected by qRT-PCR,the proliferation of SW579 cells was detected by CCK-8,the apoptosis of SW579 cells was detected by flow cytometry,the cell cycle distribution of SW579 was detected by flow cytometry,and the protein expression levels of proliferating cell nuclear antigen(PCNA),Bcl-2 related X protein(Bax)and Cyclin D1 in SW579 cells were detected by Western blot.Results The expression level of miR-551b in thyroid cancer tissues was significantly lower than that in precancerous normal tissues(P<0.05).Compared with siRNA NC group,the miR-551b level,the apoptosis rate,the cell proportion of G0/G1 phase and Bax protein level in SW579 cells were significantly decreased in miR-551b siRNA group(P<0.05),while the cell OD value,the cell proportions of S phase and G2/M phase,PCNA and Cyclin D1 protein levels were significantly increased(P<0.05).Compared with mimic NC group,the miR-551b level,the apoptosis rate,the cell proportion of G0/G1 phase and Bax protein level in SW579 cells were significantly increased in miR-551b mimic group(P<0.05),while the cell OD value,the cell proportions of S phase and G2/M phase,PCNA and Cyclin D1 protein levels were significantly decreased(P<0.05).Conclusion MiR-551b is down-regulated in thyroid cancer,and it can inhibit the proliferation and induce the apoptosis of thyroid cancer cells,which may be closely related to the occurrence and development of thyroid cancer.