Metabolic CRISPR screening identifies RPE as a key regulator of acquired enzalutamide resistance through FKBP5 destabilization in prostate cancer.

Enzalutamide is a cornerstone therapy for castration-resistant prostate cancer (CRPC), yet acquired resistance remains a major clinical challenge. Although metabolic enzymes are increasingly recognized as modulators of therapeutic response, their specific roles-particularly their non-enzymatic functions-in sustaining enzalutamide resistance remain incompletely understood. In this study, we performed an in vivo screen using a custom metabolic CRISPR library in enzalutamide-treated xenografts and identified the pentose phosphate pathway enzyme ribulose-5-phosphate 3-epimerase (RPE) as a critical driver of enzalutamide resistance. Silencing RPE markedly restored enzalutamide sensitivity, enhanced apoptosis in vitro, and significantly suppressed tumor growth in both cell line-derived and patient-derived xenograft models. Mechanistically, RPE promoted resistance independently of its canonical enzymatic activity. Instead, RPE physically interacted with FKBP5 and promoted its ubiquitin-proteasome-mediated degradation. Loss of FKBP5 subsequently hyperactivated AKT signaling, leading to increased p-BAD and BCL-xL levels and suppression of enzalutamide-induced cell death. Conversely, disrupting the RPE-FKBP5 interaction or silencing RPE in vivo using a PSMA-targeted lipid nanoparticle system effectively abrogated these resistance phenotypes. Together, these findings illustrate how CRPC cells hijack the non-enzymatic function of a metabolic enzyme to evade antiandrogen therapy, establishing the RPE-driven degradation of FKBP5 and consequent AKT hyperactivation as a targetable vulnerability for overcoming enzalutamide resistance.