PNO1 regulates autophagy and apoptosis of hepatocellular carcinoma via the MAPK signaling pathway

Background: Some studies have reported that the activated ribosomes are positively associated with malignant tumors, especially in hepatocellular carcinoma (HCC). The RNA-binding protein PNO1, as a critical ribosome has been rarely reported in human tumors. Thus, the roles of PNO1 in HCC should be explored. Methods We collected 150 formalin-fixed and paraffin-embedded (FFPE) samples and 8 fresh samples to explore the expression and prognosis of PNO1 in HCC by immunohistochemistry, Western Blotting and RT-PCR. Public databases (TCGA and GEO) were used to verify the expression and prognosis. The functions of PNO1 in HCC was verified by in vitro and in vivo experiments. The underlying molecular mechanisms of PNO1 were examined by RNA-seq analysis and a series of functional experiments. Results PNO1 expression was considerably higher in HCC tissues and the higher expression of PNO1 was associated with poor prognosis of HCC patients. In vitro experiments indicated that PNO1 overexpression promoted proliferation and depressed apoptosis of HCC cells. In addition, high expression of PNO1 increased autophagy of HCC cells. Consistent results were also observed in vivo experiments. The results of the RNA-seq analysis indicted that PNO1 as an oncogene promoted HCC progression through the MAPK signaling pathway. The results were also verified by in vivo experiments. Conclusions PNO1 was overexpressed in HCC, promoted autophagy and inhibited apoptosis of HCC cells via the MAPK signaling pathway.