LncRNA-ATB promotes autophagy by activating Yes-associated protein and inducing autophagy-related protein 5 expression in hepatocellular carcinoma

BACKGROUND Long non-coding RNAs(lnc RNAs) play important roles in many diseases,including hepatocellular carcinoma(HCC). Autophagy is a metabolic pathway that facilitates cancer cell survival in response to stress. The relationship between autophagy and the lnc RNA-activated by transforming growth factor beta(lnc RNA-ATB) in HCC remains unknown.AIM To explore the influence of lnc RNA-ATB in regulating autophagy in HCC cells and the underlying mechanism.METHODS In the present study, we evaluated lnc RNA-ATB expression in tumor and adjacent non-tumor tissues from 72 HCC cases by real-time PCR. We evaluated the role of lnc RNA-ATB in the proliferation and clonogenicity of HCC cells in vitro. The effect of lnc RNA-ATB on autophagy was determined using a LC3-GFP reporter and transmission electron microscopy. Furthermore, the mechanism by which lnc RNA-ATB regulates autophagy was explored by immunofluorescence staining, RNA immunoprecipitation(RIP), and Western blot.RESULTS The expression of lnc RNA-ATB was higher in HCC tissues than in normal liver tissues, and lnc RNA-ATB expression was positively correlated with tumor size,TNM stage, and poorer survival of patients with HCC. Moreover, ectopic overexpression of lnc RNA-ATB promoted cell proliferation and clonogenicnity of HCC cells in vitro. Lnc RNA-ATB promoted autophagy by activating Yesassociated protein(YAP). Moreover, lnc RNA-ATB interacted with autophagy-related protein 5(ATG5) m RNA and increased ATG5 expression.CONCLUSION Lnc RNA-ATB regulates autophagy by activating YAP and increasing ATG5 expression. Our data demonstrate a novel function for lnc RNA-ATB in autophagy and suggest that lnc RNA-ATB plays an important role in HCC.