High expression of long non-coding RNA SPRY4-IT1 predicts poor prognosis of clear cell renal cell carcinoma

Introduction: Long non-coding RNAs (lncRNAs) play a key role in cellular processes, such as cell growth, apoptosis, and carcinogenesis. lncRNAs SPRY4-IT1 has recently been identified to be involved in tumorigenesis of several cancers such as non-small cell lung cancer and esophageal squamous cell carcinoma. However, the role of SPRY4-IT1 in clear cell renal cell carcinoma (ccRCC) remains unclear. Methods: The expression of SPRY4-IT1 was examined in ccRCC patients and renal cancer cell lines by using quantitative real-time PCR (qRT-PCR). The relationship between SPRY4-IT1 level and clinicopathological parameters of ccRCC was analyzed with the Kaplan-Meier method and Cox proportional hazards model. Small interfering RNA (siRNA) was used to suppress SPRY4-IT1 expression in renal cancer cell line 786-O. In vitro assays were performed to further explore its role in renal cancer progressio. Results: The relative level of SPRY4-IT1 was significantly higher in ccRCC tissues compared to the adjacent normal renal tissues. And higher expression of SPRY4-IT1 was found in renal cancer cell lines compared with the normal human proximal tubule epithelial cell line HK-2. The ccRCC patients with higher SPRY4-IT1 expression had an advanced clinical stage and poorer prognosis than those with lower SPRY4-IT1 expression. Multivariate analyses by Cox's proportional hazard model revealed that expression of SPRY4-IT1 was an independent prognostic factor in ccRCC. In vitro assays, our results indicated that knockdown of SPRY4-IT1 reduced renal cancer cell proliferation, migration, and invasion. Conclusions: Our data suggested that lncRNA SPRY4-IT1 might be considered as a potential prognostic indicator and a potential target for therapeutic intervention in RC.