LncRNA AFAP1-AS1 promotes proliferation ability and invasiveness of bladder cancer cells

OBJECTIVE: It was the aim of this study to explore the role and mechanism of long non-coding RNA (IncRNA) AFAP1-AS1 in the progression of bladder cancer (BCa) by in vitro experiments. PATIENTS AND METHODS: AFAP1-AS1 levels in 40 pairs of clinical BCa tissue samples and normal ones collected from BCa patients were determined, and paired sample t-test was applied to compare the differences between groups. The prognosis data of patients with BCa were collected, and survival analysis and t-test were performed to specify the interplay between AFAP1-AS1 and the prognosis of BCa patients. Subsequently. AFAP1-AS1 expression level in BCa and normal cells were further confirmed by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR), and Cell Counting Kit-8 (CCK-8), 5-Ethyny1-2'-deoxyuridine (EdU), and transwell assays were performed to figure out the influence of this IncRNA on the proliferation ability and invasiveness of BCa cells. Meanwhile, the interaction between AFAP1-AS1 and its sense mRNA was analyzed. We used co-transfection technology to simultaneously transfect si-AFAP1-AS1 and pcDNA3.1-AFAP1 or their corresponding negative controls into BCa cells, and cell proliferation and invasion ability in different subgroups were determined to explore the underlying mechanism through which AFAP1-AS1 plays a role in BCa progression. RESULTS: No matter in BCa tissues or in cell samples, compared to the corresponding normal controls, AFAP1-AS1 was found highly expressed; at the same time, in invasive bladder cancer tissues, the expression level of AFAP1-AS1 was also higher than that in non-invasive tissues. Meanwhile, survival analysis revealed that patients with BCa with high expression of AFAP1-AS1 owned a shorter overall survival rate than those with low expression, indicating a negative interplay between AFAP1-AS1 expression and patients' prognosis. In addition, in BCa cell lines, according to the results of CCK-8, EDU, and transwell assays, the proliferative capacity, as well as the invasive ability of BCa cells, were found weakened after downregulation of AFAP1-AS1. Meanwhile, a negative interplay was discovered between AFAP1-AS1 and its sense mRNA. Finally, the results of cell reversal experiment using co-trans- fection technique revealed that overexpression of AFAP1 can reverse the inhibitory impact of IncRNAAFAP1-AS1 on the malignant ability of BCa cells. CONCLUSIONS: AFAP1-AS1 may enhance the proliferation ability as well as the invasiveness of BCa cells so as to aggravate the degree of BCa malignancy.