Upregulation of long noncoding RNA LOC440040 promotes tumor progression and predicts poor prognosis in patients with prostate cancer

BACKGROUND/PURPOSE: Long noncoding RNAs (lncRNAs) play a functional role in the initiation and progression of prostate cancer (PCa). This study aimed to determine differentially expressed lncRNA through high-throughput sequencing technology and investigate its expression, biological function and clinical correlation with PCa. MATERIALS AND METHODS: Candidate lncRNAs were identified through microarray screening and bioanalysis. The expression of lncRNA LOC440040 in PCa tissues and cell lines was determined by reverse-transcription polymerase chain reaction. The relationship between LOC440040 level and clinicopathological characteristics was analyzed by paired t-test or chi-square test, and its association with patient prognosis was assessed by the Kaplan–Meier method. The effects of LOC440040 on PC-3 and 22RV1 cells were evaluated by Cell Counting Kit-8 (CCK-8), migration, invasion and colony formation assays. RESULTS: LOC440040 expression was upregulated in PCa tissues and cell lines. Clinicopathological analysis showed that patients with high LOC440040 expression exhibited more advanced clinical features and shorter overall survival than those with low LOC440040 expression. Multivariate regression analysis revealed that LOC440040 expression was an independent prognostic factor in patients with PCa. Knockdown of LOC440040 inhibited PCa cell proliferation, migration and invasion. CONCLUSION: LOC440040 may play an oncogenic role in PCa initiation and progression. This lncRNA could be a novel molecular prognostic biomarker and a potential therapeutic target for PCa.