Inhibition of Androgen Receptor Exposes Replication Stress Vulnerability in Prostate Cancer

Standard systemic treatment for metastatic prostate cancer typically involves agents that inhibit androgen receptor (AR) signaling. Although patients initially respond well to these AR pathway inhibitors (ARPIs), the development of resistance presents a major therapeutic challenge. Our study reveals that enzalutamide, a frontline ARPI, induces DNA replication stress in AR-positive prostate cancer cells. This stress is intensified when translesion DNA synthesis (TLS) is suppressed, leading to the abnormal accumulation of single-stranded DNA (ssDNA) gaps and persistent DNA damage markers. Additionally, we show that JH-RE-06, a TLS inhibitor, significantly enhances the sensitivity of AR-positive prostate cancer cells to enzalutamide without affecting AR-negative benign cells. In a syngeneic murine tumor model, the combination of enzalutamide and JH-RE-06 suppresses tumor growth more effectively than either treatment alone or the control. These findings suggest that AR inhibition induces DNA replication stress in hormone-sensitive prostate cancer, revealing a therapeutic vulnerability that can be exploited through TLS-targeting combination therapy.