Abstract:

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 mRNAlevel was increased in 20 to 25 times, meanwhile the protein expression level also increased significantly; 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.

Key words: Bcl-2-associated athanogene 2, Proteasome inhibitor, Apoptosis, Thyroid cancer