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) pretreatment in preventing radiotherapy-induced alopecia (RIA). It was found that PGE2 reduced RIA by preventing premature termination of the anagen phase in hair follicles (HFs) and enhancing HF self-repair. PGE2 did not activate HF stem cells but preserved more transit amplifying cells (TACs) by transiently arresting them in the G1 phase, reducing TAC apoptosis and mitigating HF dystrophy. This preservation accelerated HF self-repair and bypassed premature catagen entry induced by radiotherapy. Additionally, promoting G1 arrest with palbociclib isethionate, a CDK4/6 inhibitor, offered similar protection. The findings suggested that PGE2 could be repurposed as a preventive treatment for RIA by protecting HF TACs and accelerating the regeneration of HF structures to resume anagen growth.