Ubiquitin-like modifier activating enzyme 2 promotes cell migration and invasion through Wnt/ß-catenin signaling in gastric cancer.

AIM: To investigate the function and mechanism of ubiquitin-like modifier activating enzyme 2 (Uba2) in progression of gastric cancer (GC) cells. METHODS: Uba2 level in patients with GC was analyzed by Western blotting and immunohistochemistry. MTT and colony formation assays were performed to examine cell proliferation. Flow cytometry was used for cell cycle analysis. Wound healing and Transwell assays were conducted to examine the effects of Uba2 on migration and invasion. Expression levels of cell cycle-related proteins, epithelial-mesenchymal transition (EMT) biomarkers, and involvement of the Wnt/ß-catenin pathway was assessed by Western blotting. Activation of the Wnt/ß-catenin pathway was confirmed by luciferase assay. RESULTS: Uba2 expression was higher in GC than in normal tissues. Increased Uba2 expression was correlated with tissue differentiation, Lauren's classification, vascular invasion, and TNM stage, as determined by the analysis of 100 GC cases (P < 0.05). Knock-down of Uba2 inhibited GC cell proliferation, induced cell cycle arrest, and altered expression of cyclin D1, P21, P27, and Bcl-2, while up-regulation of Uba2 showed the opposite effects. The wound healing and Transwell assays showed that Uba2 promoted GC cell migration and invasion. Western blotting revealed alterations in EMT biomarkers, suggesting the role of Uba2 in EMT. Furthermore, the luciferase reporter assay indicated the involvement of the Wnt/ß-catenin signaling pathway as a possible modulator of Uba2 oncogenic functions. CONCLUSION: Uba2 plays a vital role in GC cell migration and invasion, possibly by regulating the Wnt/ß-catenin signaling pathway and EMT.

UBA2 promotes proliferation of colorectal cancer.

Small ubiquitin­like modifier proteins are involved in tumorigenesis; however, the potential effects and functions of the family member ubiquitin­like modifier­activating enzyme 2 (UBA2) on colorectal cancer are not clear. The present study aimed to examine the effects of UBA2 on the proliferation of colorectal cancer cells in vitro and in vivo. The mRNA and protein expression levels of UBA2 in patients with colorectal cancer were measured by reverse transcription­quantitative polymerase chain reaction and immunohistochemistry, respectively. UBA2 expression levels in colorectal cancer tissues were significantly increased compared with the paracancerous normal tissues. The expression of UBA2 was also associated with higher stage colorectal cancer and poor prognosis. MTT and colony formation assays were used to examine proliferation in colorectal cancer cell lines. Flow cytometry was performed to examine the effects of UBA2 on the cell cycle and apoptosis of colorectal cancer cell lines and protein expression levels were examined by western blotting. Athymic nude mice were used to examine the ability of transfected colorectal cancer cells to form tumors in vivo. Downregulation of UBA2 inhibited the proliferation of colorectal cancer cell lines in vitro and in vivo through the regulation of cell cycle associated protein expression and apoptosis. Furthermore, downregulation of UBA2 decreased the expression levels of cyclin B1, B­cell lymphoma-2, phosphorylated protein kinase B and E3 ubiquitin­protein ligase MDM2 in colorectal cancer cells, whereas the expression levels of p21 and p27 were increased. UBA2 was demonstrated to serve an essential role in the proliferation of colorectal cancer and may be used as a potential biomarker to predict prognosis and as a therapeutic target in colorectal cancer.