Knockdown of TRIM26 inhibits the proliferation, migration and invasion of bladder cancer cells through the Akt/GSK3β/β-catenin pathway.

Tripartite motif-containing protein 26 (TRIM26) is a member of the TRIM protein family and has been demonstrated to play crucial roles in several types of cancers. However, the biological role of TRIM26 in bladder cancer and the mechanism have not been studied. In this study, we investigated the expression of TRIM26 in bladder cancer tissues and their adjacent non-tumor tissues by Western blot and qRT-PCR. In vitro investigations were performed to assess the roles of TRIM26 in bladder cancer using TRIM26-silencing and TRIM26-overexpressing bladder cancer cell lines. MTT and EdU assays were performed to evaluate cell proliferation. Cell migration and invasion were determined by transwell assays. Western blot analysis was performed to detect the expression levels of p-Akt, Akt, p-GSK3β, GSK3β, β-catenin and c-Myc. Our results showed that TRIM26 expression was upregulated in human bladder cancer tissues and cell lines at both mRNA and protein levels. Knockdown of TRIM26 significantly inhibited the proliferation, migration and invasion of bladder cancer cells. In contrast, TRIM26 overexpression promoted bladder cancer cell proliferation, cell migration and invasion. Furthermore, knockdown of TRIM26 significantly decreased the levels of p-Akt, p-GSK3β, β-catenin and c-Myc in bladder cancer cells. Additionally, induction of Akt by SC79 treatment reversed the inhibitory effects of TRIM26 knockdown on the cellular behaviors of bladder cancer cells, while inhibition of β-catenin reversed the effects of TRIM26 overexpression on the behaviors. Finally, knockdown of TRIM26 attenuated the growth of tumor xenografts in nude mice. In conclusion, these findings demonstrated that TRIM26 exerted an oncogenic role in bladder cancer through regulation of cell proliferation, migration and invasion via the Akt/GSK3β/β-catenin pathway.