Downregulated m⁵C regulator NSUN6 enhances proliferation, migration and affects immune regulation in ovarian cancer

Ovarian cancer (OC) remains one of the most lethal gynecological malignancies, largely due to late diagnosis and high metastatic potential. RNA 5-methylcytosine (m⁵C) modification has emerged as a key regulatory mechanism in cancer biology, yet the role of m⁵C-related genes such as NSUN6 in OC remains poorly understood. In this study, we first obtained three OC datasets and one m5C-related dataset from the GEO database and identified differentially expressed genes (co-DEGs) using Venn diagram analysis. Kaplan Meier plotter showed that NSUN6 was the only regulator significantly associated with patient prognosis. Additionly, Western Blot, Online database analysis and immunohistochemical staining evaluation showed that NSUN6 was significantly downregulated in OC and negatively correlated with tumor stage, metastasis and survival. Next, we overexpressed NSUN6 in OC cell lines. CCK8, wound healing and Transwell assays demonstrated that NSUN6 overexpression inhibited OC cell proliferation, migration, and invasion. Rescue experiments confirmed NSUN6-mediated suppression of AKT phosphorylation. In vivo xenograft models confirmed the tumor-suppressive effect of NSUN6, showing reduced tumor burden in both intraperitoneal and subcutaneous models. Bioinformatic analyses revealed enrichment in immune-related pathways and correlations with immune infiltration markers, which were further validated using ovarian cancer clinical samples. Collectively, our results demonstrate that NSUN6 is downregulated in OC and suppresses OC proliferation, migration, and invasion by inhibiting AKT activity, highlighting its potential as a therapeutic target in OC.