Upregulation of valosin-containing protein (VCP) is associated with poor prognosis and promotes tumor progression of orbital B-cell lymphoma

OBJECTIVE: This study aimed to investigate the relationship between VCP expression and the prognosis of orbital B-cell lymphoma patients and the influence of downregulation of VCP on the apoptosis and invasion abilities of lymphoma cells. METHODS: We recruited 66 orbital B-cell lymphoma patients. VCP expression in 66 samples of orbital B-cell lymphoma was determined by immunohistochemistry using monoclonal VCP antibodies. Based on VCP-expression levels detected by immunohistochemistry, we chose ten cases of orbital tumor paraffin tissue from the patients. Total RNA was extracted and differences in VCP gene-expression levels compared among patients using quantitative reverse-transcription (qRT) PCR. We used siRNA to knock down VCP in the lymphoma cell lines Raji and SUDHL4. qRT-PCR and Western blot were applied to detect VCP mRNA and protein expression, respectively. SUDHL48 assays were applied to investigate cell proliferation. Hoechst 33258 staining and flow-cytometry analysis were applied to investigate cell apoptosis. Transwell assays were applied to investigate invasive ability. Survival analysis was used to evaluate prognostic values. RESULTS: Expression levels of VCP were correlated with the stage, tumor grade, and recurrence rate of patients. VCP mRNA-expression levels were consistent with VCP-expression levels in orbital B-cell lymphoma tissue. Moreover, survival analysis revealed that lower VCP-expression levels were correlated with longer overall survival of orbital B-cell lymphoma patients. Down-regulation of VCP with siRNA did not inhibit cell proliferation. However, it dramatically increased apoptosis and suppressed the invasion of B-cell lymphoma cells. CONCLUSION: VCP expression played an important role in the progression of orbital B-cell lymphoma. VCP could be a useful marker for predicting the prognosis of orbital B-cell lymphoma patients. VCP may be a potential therapeutic target for orbital B-cell lymphoma.