Long noncoding RNA AFAP1-AS1 indicates a poor prognosis of hepatocellular carcinoma and promotes cell proliferation and invasion via upregulation of the RhoA/Rac2 signaling

It has been shown that long noncoding RNAs (lncRNAs) play a critical role in the regulation of cellular processes including cancer progression and metastasis. However, the biological functions and clinical significance of lncRNA AFAP1-AS1 in hepatocellular carcinoma (HCC) remain unclear. Expression of AFAP1-AS1 was analyzed in 78 HCC tissues by real-time PCR. The effect of AFAP1-AS1 on cell proliferation was examined by MTT assay, cell apoptosis was detected by flow cytometric analysis and cell invasion was determined by Transwell assay. RhoA/Rac2 signaling and downstream factors were verified by western blotting. HCC cells infected with si-AFAP1-AS1 were injected into nude mice to investigate the effect of AFAP1-AS1 on the tumorigenesis in vivo. We found that increased expression of AFAP1-AS1 was significantly correlated with pathological staging (P=0.024) and lymph-vascular space invasion (LVSI) in HCC patients (P=0.007). Multivariate analyses indicated that AFAP1-AS1 represented an independent predictor for overall survival of HCC (P=0.029). Further experiments showed that knockdown of AFAP1-AS1 by si-AFAP1-AS1 decreased the proliferation and invasion in vitro and in vivo, induced cell apoptosis and blocked cell cycle in S phase via inhibition of the RhoA/Rac2 signaling. Taken together, our findings indicate that AFAP1-AS1 may promote the HCC development through upregulation of RhoA/Rac2 signaling and provide a potential therapeutic target for HCC.