背景与目的：蛋白酶体抑制剂对不同组织来源的肿瘤均有抑制其增长和促进细胞凋亡的作用，其作用机制可能与Bcl-2相关抗凋亡基因2(Bcl-2-associated athanogene 2，BAG2)有关，本研究探讨BAG2在蛋白酶体抑制剂诱导甲状腺癌细胞凋亡中的作用。方法：选取人甲状腺未分化癌细胞系ARO、FRO、KTC1、KTC2、KTC3、8305C和8505C，分别设培养液处理空白对照组、蛋白酶体抑制剂MG132处理组；利用实时定量逆转录聚合酶链反应(quantitative real-time polymerase chain reaction，qRT-PCR)检测各组细胞BAG2 mRNA表达及MG132诱导其表达的时效性；利用蛋白质印迹法(Western blot)检测各组细胞BAG2蛋白表达。结果：MTT结果显示，FRO和KTC2细胞系对蛋白酶体抑制剂最为敏感，与空白对照组相比，MG132能不同程度的增加各种细胞BAG2 mRNA及蛋白的表达水平(P<0.01)，在FRO和KTC2细胞中，BAG2 mRNA水平较对照组增加20~25倍，蛋白质的表达水平也显著增加；时间效应实验中，敏感的FRO细胞BAG2 mRNA水平增加快，没有延迟期；并且增加的最高水平显著高于非敏感的ARO细胞(P<0.01)。结论：BAG2是由蛋白酶体抑制作用诱导产生的新型分子，在蛋白酶体抑制剂诱导的甲状腺癌细胞的死亡中起着促凋亡作用。%Background and purpose: For neoplasms with different sources, proteasome inhibitors can inhibit their growth and promote the cell apoptosis. Its mechanism may be associated with Bcl-2-associated athanogene 2 (BAG2). We aimed to investigate the involvement of in thyroid cancer cell death induced by proteasome inhibitors. Methods:A panel of thyroid cancer cells (ARO, FRO, KTC1, KTC2, KTC3, 8305C and 8505C) were treated with vehicle or proteasome inhibitor MG132;BAG2 mRNA and protein levels were analyzed using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot, respectively. Results:MTT results indicated that FRO and KTC2 cell lines were the most sensitive to proteasome inhibitors. MG132 induced BAG2 mRNA and protein expression in the panel of thyroid cancer cells with various degree (P<0.01), for FRO and KTC2 cell line, the BAG2 mRNA level was increased in 20 to 25 times, meanwhile the protein expression level also increased signiifcantly;Sensitive FRO cells demonstrated quicker induction of BAG2 compared with insensitive ARO cells. Moreover, the extents of BAG2 induction in FRO cells were higher than that in ARO cells. Conclusion: BAG2 is a novel molecule induced by proteasome inhibitor, which might function as a proapoptotic molecule in thyroid cancer cell death mediated by proteasome inhibitor.
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