The potential role of AhR/NR4A1 in androgen-dependent prostate cancer: focus on TCDD-induced ferroptosis.

Prostate cancer (PCa) is a complex disease with diverse molecular alterations. The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that exhibits pleiotropic roles in PCa, and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a potent ligand for AhR. While targeting ferroptosis is an innovative PCa therapeutic strategy, the impact of AhR on this process remains unclear. This study aimed to investigate the influence of AhR on lipid peroxidation and ferroptosis. Results showed that TCDD activated AhR, as evidenced by increased CYP1A1 expression, leading to reduced cell viability. TCDD caused mitochondria shrinkage, decreased the GSH/GSSG ratio, and elevated the MDA levels and lipid peroxidation. Interestingly, AhR knockdown reversed these effects, similar to the action of ferroptosis inhibitors. Mechanistically, TCDD suppressed nuclear receptor subfamily 4 group A member 1 (NR4A1) expression, in part due to AhR activation. This suppression subsequently led to a reduction in the expression of the NR4A1 downstream target stearoyl-CoA desaturase 1 (SCD1). NR4A1 overexpression counteracted the effects of TCDD. In vivo, TCDD activated AhR, downregulated NR4A1 and SCD1 expression, induced mitochondria shrinkage, and increased the MDA and 4-hydroxynonenal (4-HNE) levels. In summary, TCDD promotes ferroptosis in androgen-dependent PCa via inhibiting the NR4A1/SCD1 axis, in part dependent on AhR activation.