RNA 5-methylcytosine writer NSUN5 promotes hepatocellular carcinoma cell proliferation via a ZBED3-dependent mechanism

Hepatocellular carcinoma (HCC) is one of the leading contributors to cancer-related mortality worldwide. Nop2/Sun domain family member 5 (NSUN5), a conserved RNA 5-methylcytosine methyltransferase, is conventionally recognized as oncogenic. However, its role in HCC development remains unknown. In this study, we observed a remarkable upregulation of NSUN5 expression in both tumor tissues from patients with HCC, establishing a correlation with unfavorable clinical outcomes. NSUN5 knockdown and overexpression significantly inhibited and promoted HCC cell proliferation, respectively. Additionally, employing a combination of methylated RNA immunoprecipitation sequencing (MeRIP-seq) and RIP-seq techniques, we identified zinc finger BED domain-containing protein 3 (ZBED3) as a novel downstream target of NSUN5. Additionally, we found that the overexpression of ZBED3 counteracted the tumor-suppressing effect of NSUN5 knockdown and simultaneously reversed the inhibition of the Wnt/β-catenin signaling pathway. In summary, we elucidated the oncogenic role of NSUN5 in HCC development and identified the ZBED3/Wnt/β-catenin signaling pathway as its downstream target. This study provides a novel therapeutic target for further development in HCC treatment.