The evolutionarily conserved genes that encode the tripartite motif (TRIM) protein family are involved in various biological processes, including cellular immunity, inflammatory reaction, antiviral activity, and tumor progression. One member of this protein family, Trim59, has been reported as a novel biomarker for the occurrence and progression of multiple human carcinomas, such as lung cancer, gastric cancer, cervical cancer, and osteosarcoma. However, little is known about the relationship between Trim59 and bladder carcinogenesis. In this study, we examined the expression of Trim59 in bladder cancer (Bca) specimens and cell lines, and investigated its biological roles in Bca cell lines. We found that Trim59 was upregulated in Bca tissues and cell lines. In addition, using transwell chamber assays and the cell scratch test, we determined that knockdown of Trim59 significantly inhibited the epithelial-mesenchymal transition (EMT) and the processes of cell invasion and migration in Bca cell lines. Furthermore, we found that downregulated Trim59 expression could also inhibit cell proliferation and promote apoptosis. As a result, we demonstrated that the effects of Trim59-induced EMT and invasion/migration in Bca cells were achieved by the activation of the transforming growth factor beta/Smad2/3 signaling pathway. Our findings also revealed that Trim59 can present oncogenic activity, and may serve as a novel candidate target for bladder carcinoma treatment.
Keywords: EMT; Smad2/3; TGF-β; Trim59; bladder carcinoma; metastasis.