NSUN5 promotes progression and predicts poor prognosis in hepatocellular carcinoma

The 5-methylcytosine (m5C) RNA methyltransferase NOP2/Sun RNA methyltransferase 5 (NSUN5) has been reported to serve important roles in numerous diseases. However, the functions and clinical significance of NSUN5 in hepatocellular carcinoma (HCC) remain unknown. Clinical information and NSUN5 mRNA sequencing data for 374 patients with HCC were downloaded from The Cancer Genome Atlas (TCGA) database, and NSUN5 mRNA and protein expression levels in 120 patients with HCC (present study cohorts) were assessed using reverse transcription-quantitative PCR, western blotting or immunohistochemistry. The association between NSUN5 mRNA and protein expression levels and the clinical characteristics (or prognosis) of patients with HCC was analyzed using the χ(2) or log-rank test. The functions of NSUN5 in HCC were evaluated using in vitro and in vivo experiments, and the mechanism by which NSUN5 affected the progression of HCC was assessed using bioinformatics analysis using LinkedOmics. NSUN5 was significantly upregulated and predicted poor prognosis in HCC according to data from both TCGA database and present study cohorts. NSUN5 significantly promoted HCC proliferation and migration in vitro and significantly induced HCC tumor growth in vivo. Bioinformatics analysis demonstrated that NSUN5 was positively correlated with genes associated with translation in HCC. It was hypothesized that overexpression of NSUN5 strengthened ribosome functions and global protein translation, which may promote the proliferation and migration of HCC. In conclusion, NSUN5 may promote the progression of HCC by enhancing translation, thus making it a potential target for HCC treatment.