UBR5 oncogene as an indicator of poor prognosis in gastric cancer.

The human ubiquitin protein ligase E3 component N-recognin 5 (UBR5) gene, which is localized to chromosome 8q22, encodes an ~10 kb mRNA and a >300 kDa protein, which can be detected in a number of cell types. UBR5 is implicated in several types of cancer, including ovarian cancer, gallbladder cancer and lymphoma; however, its role in gastric cancer is not completely understood. In the present study, the expression levels of UBR5 in human gastric cancer tissues and cell lines were examined via immunohistochemistry, reverse transcription-quantitative PCR analysis and western blotting. Furthermore, the association between UBR5 expression and clinicopathological characteristics, as well as the prognosis of patients with gastric cancer, were examined. In addition, the role of UBR5 in gastric cancer cell proliferation, invasion and migration was investigated by conducting MTS, Transwell and wound healing assays, respectively. The results indicated that the mRNA and protein expression levels of UBR5 were significantly increased in gastric cancer tissues compared with para-carcinoma tissues. High UBR5 expression levels were significantly associated with larger tumor size, advanced TNM stage and lymph node metastasis. In addition, high UBR5 expression indicated a poor prognosis in patients with gastric cancer. Furthermore, in vitro experiments demonstrated that UBR5 knockdown was associated with reduced HGC-27 gastric cancer cell proliferation, invasion and migration compared with the small interfering RNA control group. Therefore, the results indicated that UBR5 may serve a key role in gastric cancer, indicating that UBR5 may also serve as an important prognostic biomarker.