Dihydrotestosterone-androgen receptor signaling suppresses EBV-positive gastric cancer through DNA demethylation-mediated viral reactivation.

[BACKGROUND] Our Kaplan-Meier analysis reveals that gastric cancer patients with high androgen receptor (AR) expression demonstrate poorer survival outcomes compared to those with low AR expression, particularly in patients with characteristics typical of EBV-positive gastric cancer. However, the molecular mechanisms driving this seemingly contradictory relationship have remained poorly understood, as our experimental findings suggest AR signaling actually suppresses tumor growth in EBVaGC.

[METHODS] The study utilized AR-positive EBV-infected gastric cancer cell lines treated with dihydrotestosterone (DHT) to investigate molecular pathways. Comprehensive analyses included examination of apoptosis, miRNA expression, signaling pathways, DNA methylation patterns, and viral gene expression. In vivo validation was performed using xenograft models with MKN1-EBV and SNU719 cells to assess tumor growth and immune response.

[RESULTS] DHT treatment triggered early apoptosis through upregulation of pro-apoptotic miRNAs, particularly miR-204-5p, while activating the PI3K-Akt pathway and enhancing DNA damage response through increased phosphorylation of key proteins. The treatment reduced DNMT3A expression, leading to genome-wide DNA demethylation and increased expression of both lytic (BZLF1) and latent (EBNA1, LMP1) EBV genes. Xenograft studies confirmed these findings, showing reduced tumor growth, increased lymphocyte infiltration, and enhanced viral gene expression specifically in AR-positive tumors.

[CONCLUSION] The study reveals that AR signaling suppresses EBV-positive gastric cancer by modulating both cellular apoptosis and EBV reactivation through epigenetic mechanisms. These findings suggest that AR agonists might have therapeutic potential in treating AR-positive EBV-associated gastric cancer.