Abstract
TRIM59 has been recently implicated in the carcinogenesis of several cancers such as lung cancer, gastric cancer, and bladder cancer. However, its expression pattern and clinical significance has not been investigated in human breast cancer. In the present study, we examined TRIM59 protein expression in 95 cases of breast cancer tissues using immunohistochemistry. We found that TRIM59 was upregulated in 42 out of 95 cases and correlated with TNM stage (P = 0.0056), lymph node metastasis (P = 0.0088) and poor prognosis (P = 0.0092). Importantly, TRIM59 level was higher in triple-negative breast cancer (TNBC) (P = 0.0157). Expression of TRIM59 protein was also upregulated in breast cancer cell lines compared to normal MCF-10A cell line. TRIM59 plasmid and shRNA transfection was performed in MCF-7 and SK-BR-3 cells respectively. TRIM59 overexpression promoted cell proliferation, invasion, migration, cell cycle transition, and paclitaxel resistance, whereas TRIM59 depletion showed the opposite results. Further analysis showed that TRIM59 overexpression upregulated expression of cyclinA, cyclinE, Bcl-xl, Bcl-2, p-AKT, and downregulated expression of p21, p27, p53. AKT inhibitor treatment abolished the effect of TRIM59 on Bcl-2 expression. TRIM59 overexpression also upregulated the level of p53 ubiquitination. In conclusion, TRIM59 overexpression correlates with poor prognosis and promotes malignant behavior through regulation of AKT pathway in human breast cancer.