LncRNA TP73-AS1 predicts the prognosis of bladder cancer patients and functions as a suppressor for bladder cancer by EMT pathway

Highlights: • LncRNA TP73-AS1 is identified with downregulation in bladder cancer tissues and cell lines. • Patients with low TP73-AS1 have shorter overall survival and progression-free survival. • Overexpression of TP73-AS1 can inhibit cell growth, migration, and invasion in vitro study. • Overexpression of TP73-AS1 inhibits metastasis of bladder cancer cell through inactivating EMT pathway. • We firstly reported the tumor suppressor function of TP73-AS1 in bladder cancer. Long noncoding RNAs (lncRNAs) have been identified to have more and more important roles in tumorigenesis and may be novel biomarker for cancer therapy. LncRNA TP73-AS1 is a novel identified lncRNA that has been demonstrated to be increased in several cancers, however, its function in bladder cancer remains unknown. The aim of this work was to examine the expression and role of lncRNA TP73-AS1 in bladder cancer. The expression levels of lncRNA TP73-AS1 in bladder cancer tissues and cell lines were determined by quantitative real-time PCR (qRT-PCR), and its clinical significance was assessed by statistical analysis. Moreover, by gain-of-function assay, the effect of TP73-AS1 on proliferation, cell cycle, apoptosis, migration and invasion was examined in bladder cancer cells. We identified that the expression level of TP73-AS1 was significantly down-regulated in bladder cancer tissues and cells compared to adjacent non-tumor tissues. Kaplan-Meier survival analysis found that patients with low TP73-AS1 expression level had shorter overall survival and progression-free survival than those with high TP73-AS1 expression. Moreover, we showed that overexpression of TP73-AS1 could inhibit cell growth, arrest cell cycle, reduce cell migration and invasion, and promote cell apotosis in vitro study. In addition, overexpression of TP73-AS1 diminished epithelial-mesenchymal transition (EMT) through inhibiting the expression of vimentin, snail, MMP-2, and MMP-9 and upregulating the expression levels of E-cadherin. Collectively, our findings for the first time elucidated that lncRNA TP73-AS1 may serve as a tumor suppressor participated in bladder cancer progression, which provided a promising therapy strategy for patients with bladder cancer.