A novel lncRNA PLK4 up-regulated by talazoparib represses hepatocellular carcinoma progression by promoting YAP-mediated cell senescence

A growing number of studies recognize that long non-coding RNAs (lncRNAs) are essential to mediate multiple tumorigenic processes, including hepatic tumorigenesis. However, the pathological mechanism of lncRNA-regulated liver cancer cell growth remains poorly understood. In this study, we identified a novel function lncRNA, named polo-like kinase 4 associated lncRNA (lncRNA PLK4, GenBank Accession No. RP11-50D9.3), whose expression was dramatically down-regulated in hepatocellular carcinoma (HCC) tissues and cells. Interestingly, talazoparib, a novel and highly potent poly-ADP-ribose polymerase 1/2 (PARP1/2) inhibitor, could increase lncRNA PLK4 expression in HepG2 cells. Importantly, we showed that talazoparib-induced lncRNA PLK4 could function as a tumour suppressor gene by Yes-associated protein (YAP) inactivation and induction of cellular senescence to inhibit liver cancer cell viability and growth. In summary, our findings reveal the molecular mechanism of talazoparib-induced anti-tumor effect, and suggest a potential clinical use of talazoparib-targeted lncRNA PLK4/YAP-dependent cellular senescence for the treatment of HCC.