Long Noncoding RNA p53‐Stabilizing and Activating RNA Promotes p53 Signaling by Inhibiting Heterogeneous Nuclear Ribonucleoprotein K deSUMOylation and Suppresses Hepatocellular Carcinoma

To identify hepatocellular carcinoma (HCC)‐implicated long noncoding RNAs (lncRNAs), we performed an integrative omics analysis by integrating mRNA and lncRNA expression profiles in HCC tissues. We identified a collection of candidate HCC‐implicated lncRNAs. Among them, we demonstrated that an lncRNA, which is named as p53‐stabilizing and activating RNA (PSTAR), inhibits HCC cell proliferation and tumorigenicity through inducing p53‐mediated cell cycle arrest. We further revealed that PSTAR can bind to heterogeneous nuclear ribonucleoprotein K (hnRNP K) and enhance its SUMOylation and thereby strengthen the interaction between hnRNP K and p53, which ultimately leads to the accumulation and transactivation of p53. PSTAR is down‐regulated in HCC tissues, and the low PSTAR expression predicts poor prognosis in patients with HCC, especially those with wild‐type p53. Conclusion: This study sheds light on the tumor suppressor role of lncRNA PSTAR, a modulator of the p53 pathway, in HCC.