Combined Dihydroartemisinin and Eupatilin Suppress Prostate Cancer through AR-Associated Ferroptosis and Modulation of Macrophage-Tumor Crosstalk.

Persistent androgen receptor (AR) signaling, metabolic alterations, and changes in the immune microenvironment are contributing factors to the progression of prostate cancer (PCa); however, therapeutic strategies capable of simultaneously targeting these interconnected vulnerabilities remain limited. Here, we identify a combinatorial regimen consisting of dihydroartemisinin and eupatilin (D&E) as a suppressor of PCa progression through coordinated disruption of tumor-intrinsic survival signaling and protumor immune interactions. Functionally, D&E suppressed the proliferation of PCa cells. Mechanistically, D&E induces ferroptosis in PCa cells, as evidenced by lipid peroxidation, intracellular iron accumulation, malondialdehyde elevation, and glutathione reduction. We further identified AR as an important target of D&E and found that it promotes resistance to ferroptosis by sustaining the SLC7A11 antioxidant axis through transcriptional activation of SLC7A11. Upstream, D&E inhibited the NF-κB subunit p65, which transcriptionally maintains AR expression, thus establishing an NF-κB/AR/SLC7A11 signaling cascade underlying ferroptosis resistance in PCa. Beyond tumor-intrinsic effects, D&E also remodels the tumor microenvironment. Specifically, AR-high tumor cells were found to facilitate M2-like macrophage polarization. In turn, M2-like macrophages could secrete SPP1, which potentially augments malignant properties and AR signaling in tumor cells via the CD44 pathway, thereby constituting a protumorigenic positive feedback loop. Notably, D&E attenuated the M2-like phenotype, reduced SPP1 secretion, and reduced macrophage-mediated promotion of PCa proliferation. In immunocompetent mouse models, D&E further synergized with anti-PD-L1 to suppress PCa progression. Together, these findings indicate that D&E exert antitumor effects in PCa by promoting ferroptosis-associated cell death and modulating macrophage-associated microenvironmental signaling, with potential therapeutic relevance particularly in AR-positive PCa.