SUV family histone methyltransferases correlate with nuclear lamina remodeling and clinical outcome in cancer: integrative pan-cancer TCGA analysis and experimental evidence.

Epigenetic regulation of chromatin structure is a key determinant of transcriptional control and nuclear organization in cancer. Among histone lysine methyltransferases, SUV39H1 and SUV39H2 catalyze the trimethylation of histone H3 lysine 9 (H3K9me3), establishing repressive heterochromatin domains that are important for genomic stability. However, their pan-cancer expression dynamics, prognostic value, and structural implications remain poorly defined. In this study, we performed an integrative analysis of SUV39H1 and SUV39H2 across the Cancer Genome Atlas (TCGA) cohort to investigate their expression, prognostic relevance, associations with the immune landscape, and interactions with nuclear lamina genes. Both enzymes were significantly overexpressed in multiple tumor types, with SUV39H2 showing particularly high expression in high-grade serous ovarian cancer (HGSOC), where elevated levels correlated with poor overall survival (HR = 3.27, p < 0.001). Immune infiltration analysis revealed that high SUV39H2 expression was inversely associated with tumor-infiltrating lymphocytes, indicating reduced immune infiltration. Correlation studies demonstrated strong positive associations between SUV39H1/H2 and Lamin B genes (LMNB1, LMNB2), suggesting an association with nuclear lamina-linked heterochromatin. Conversely, Lamin A (LMNA) exhibited weak or negative correlation with SUV39 enzymes. Functional validation in A2780 ovarian cancer cells demonstrated that pharmacological inhibition of SUV39H2 by Chaetocin resulted in the upregulation of Lamin A, suggesting that SUV39H1/H2 inhibition is associated with Lamin A regulation. Collectively, our findings uncover a previously underappreciated association between SUV39H2, chromatin-lamina interactions, and immune evasion in ovarian cancer, highlighting SUV39H2 as a potential chromatin-associated biomarker and regulator of nuclear organization and providing a rationale for targeting SUV39H2 in therapeutic epigenetic interventions.