Running session-conditioned human serum lowers prostate cancer cell spheroid formation

Purpose: Physical activity is associated with a lower mortality and recurrence risk in cancer, yet the underlying mechanisms remain unclear. This study aimed to evaluate the effects of running sessions on the tumorigenic potential of prostate cancer cells using a 3D in vitro model. Methods: Fifteen healthy males completed two outdoor running sessions (5 km and 10 km), interspersed by 1 month of wash-out time. Blood samples were collected before (PRE), immediately after (POST), and 3 h after (POST-3 h) sessions. Human serum (HS) samples were used to stimulate LNCaP and PC3 cell lines in 3D in vitro culture technique. The spheroid formation ability was quantified after 21 days of incubation, using GelCount. Results: In both prostate cancer cell lines, a reduction in spheroid number was shown, by both running sessions and in all timepoints considered (LNCaP cells: 5 km: - 23.8%; 10 km: - 5.6% POST HS; 5 km: - 37.8%; 10 km: - 34.8% POST-3 h HS; PC3 cells: 5 km: - 14%; 10 km: - 15.9% POST HS; 5 km: - 14.2%; 10 km: - 13% POST-3 h HS). The spheroid volume was reduced by 42.6% (5 km) and 51.1% (10 km) with POST-3 h HS, in LNCaP cells; no significant reduction was observed in PC3 cells. No differences were found between the running sessions, while higher muscle mass, cardiorespiratory fitness and age were associated with greater reductions in spheroid number and volume, especially in LNCaP cells. Conclusion: Running sessions reduce prostate cancer cell spheroid formation, especially in participants with higher physical fitness. Shorter running distances showed comparable effects to longer ones, highlighting practical implications for real-world exercise prescriptions in oncology.