Long noncoding RNA ASAP1-IT1 promotes cancer stemness and predicts a poor prognosis in patients with bladder cancer

Urinary bladder cancer (UBC) is one of the most common urogenital malignancies. Cancer stem-like cells (CSCs) play a vital role in tumor development and recurrence. Long noncoding RNAs (lncRNAs) are reported to influence cancer progression via transcriptional, posttranscriptional or epigenetic regulation. Dysregulation of several lncRNAs has been implicated in UBC. In our study, we found that an uncharacterized lncRNA, ASAP1-IT1, was overexpressed in UBC tissues compared with adjacent non-malignant tissues. High ASAP1-IT1 expression levels in UBC specimens were correlated with advanced tumor stage, higher clinical stage, poor pathological differentiation and bad overall survival. We further found that depletion of ASAP1-IT1 in T24 cells by RNA interference reduced the stemness of bladder cancer, whereas forced overexpression of ASAP1-IT1 in J82 cells enhanced cancer cell stemness by sphere assay, ALDEFLUOR and flow cytometry assay on CD44(+) population. Our data suggest that ASAP1-IT1 plays an oncogenic role in bladder cancer and can be used as a potential prognostic and therapeutic target.