Targeting Long Non-Coding RNA TTN-AS1 Suppresses Bladder Cancer Progression

Background: To explore the biological and clinical effects of titin-antisense RNA1 (TTN-AS1) in bladder cancer (BC) and the association between TTN-AS1 and activating transcription factor 2 (ATF2) in BC. Methods: The Kaplan-Meier method was performed to analyze the association between the expression of TTN-AS1 and prognosis of BC patients from TCGA data set and our institution. Quantitative real-time PCR (RT-PCR) was conducted to explore the expression of TTN-AS1 between the patients who underwent TURBT and Re-TURBT. MTT, colony formation, and tumor formation assays were conducted to evaluate the effect of TTN-AS1 on the ability of proliferation in BC cell lines. Transwell assay was performed to evaluate the effect of TTN-AS1 on the ability of invasion in BC cell lines. Bioinfomatics and immunohistochemical staining was used to identify the relationship between TTN-AS1 and ATF2. Results: The higher expression of TTN-AS1 was related to poorer disease-free survival (DFS) in patients with BC. The expression of TTN-AS1 was higher in BC patients who underwent Re-TURBT compared with BC patients who underwent TURBT. Knocking down TTN-AS1 resulted in inhibiting the ability of proliferation and invasion of BC cells. ATF2 may serve as a downstream target of TTN-AS1 in BC, and the high expression of ATF2 is also related to adverse DFS. Conclusion: Our study reveals that TTN-AS1 serves as an oncogene by activating ATF2 in BC. The findings suggest that TTN-AS1 may act as a novel therapeutic target for patients with BC.