Prostaglandin E2 Prevents Radiotherapy-Induced Alopecia by Attenuating Transit Amplifying Cell Apoptosis Through Promoting G1 Arrest

The study investigated the effect of prostaglandin E2 (PGE2) in preventing radiotherapy-induced alopecia (RIA) by focusing on its impact on hair follicle (HF) transit amplifying cells (TACs). PGE2 pretreatment was found to reduce RIA by enhancing HF self-repair and preventing premature termination of the anagen phase. It achieved this by transiently arresting TACs in the G1 phase, which reduced their radiosensitivity and apoptosis, thus mitigating HF dystrophy. This process preserved more TACs for regeneration, accelerating HF self-repair and avoiding premature catagen entry. Additionally, systemic administration of the CDK4/6 inhibitor palbociclib isethionate showed similar protective effects. The findings suggested that PGE2 could be repurposed as a preventive treatment for RIA by promoting G1 arrest and accelerating HF regeneration.