Purpose: Although several mechanisms have been proposed for the tumor-suppressive effect of exercise, little attention has been given to myokines even though skeletal muscle is heavily recruited during exercise resulting in myokine surges. We measured resting serum myokine levels before and after an exercise-based intervention and the effect of this serum on prostate cancer cell growth.
Methods: Ten prostate cancer patients undertaking androgen deprivation therapy (ADT) (age 73.3 ± 5.6 yrs) undertook a 12-week exercise-based intervention including supervised resistance training, self-directed aerobic exercise, and protein supplementation. Body composition was assessed by dual-energy x-ray absorptiometry (DXA) and muscle strength by the one-repetition maximum (1RM) method. Fasting blood was collected at baseline and post-intervention, and serum levels of myokines: SPARC, OSM, decorin, IGF-1, and IGFBP-3 were measured. The growth of the prostate cancer cell line DU145 with baseline and post-intervention serum was measured.
Results: Bodyweight (p = 0.011), fat mass (p = 0.012), and percent body fat (p = 0.033) were reduced, while percent lean mass (p = 0.001) increased as did strength (leg press, p = 0.006; chest press, p = 0.020) across the intervention. Serum OSM levels (p = 0.020) and relative serum OSM levels (p = 0.020) increased compared to baseline. A significant reduction in DU145 Cell Index (p = 0.012) and growth rate (p = 0.012) was observed after applying post-intervention serum compared to baseline serum.
Conclusion: This study provides evidence for enhanced myokine expression and tumor-suppressive effects of serum from chronically exercise-trained prostate cancer patients on ADT.