URM1 Promoted Tumor Growth and Suppressed Apoptosis via the JNK Signaling Pathway in Hepatocellular Carcinoma

Objective: Ubiquitin-related modifier 1 (URM1) is a member of the ubiquitin-like regulator family, which acts as a post-translational protein modifier in the oxidative emergency response mechanism. Previous studies have shown that URM1 may be involved in the process of apoptosis and may play a role in JNK signaling pathway. In this study, we aimed to investigate the role and possible mechanism of URM1 in HCC progression. Patients and Methods: Expression of URM1 was determined in 90 pairs of matched liver cancer and adjacent non-cancerous tissues by immunohistochemistry. The impacts of URM1 on HCC cell proliferation, apoptosis, migration and invasion capacities were verified by CCK-8, colony formation, TUNEL staining, wound healing assay and transwell, respectively. Then, the effect of URM1 on subcutaneous tumor formation in vitro was explored by nude mouse xenograft model of liver cancer. Finally, the expression of apoptosis-related proteins was analyzed in URM1 knockdown samples by Western blotting. Results: In this study, compared with paired adjacent non-cancerous tissues, the expression of URM1 was higher in liver cancer tissues (P <0.01). Kaplan-Meier survival analysis showed that high URM1 expression was significantly associated with poor prognosis (P <0.05). Moreover, URM1 knockdown inhibited liver cancer cell proliferation and migration. Furthermore, URM1 knockdown promoted apoptosis of liver cancer cells. At the same time, URM1 knockdown inhibited tumor growth in nude mouse xenograft model of liver cancer. In addition, URM1 knockdown downregulated the expression of the apoptosis-related factors INK1/2 and TP53 and upregulated the phosphorylation of INK1/2 and P53. Conclusion: In summary, our results suggested that URM1 expression is increased in liver cancer tissues, and URM1 knockdown inhibits the proliferation and migration of liver cancer cells and accelerates apoptosis. High URM1 expression is associated with poor prognosis in patients with HCC.