A single bout of resistance or high-intensity interval training increases anti-cancer myokines and suppresses cancer cell growth in vitro in survivors of breast cancer

Purpose: Breast cancer is the leading cause of cancer-related death in women, highlighting the need for strategies to mitigate recurrence and mortality. We examined the effects of a single bout of resistance training (RT) versus high-intensity interval training (HIIT) on anti-cancer myokines and in vitro cancer cell suppression. Methods: Thirty-two survivors of breast cancer were randomly allocated to a single bout of RT (n = 16) or HIIT (n = 16). Blood was collected before, immediately post (0P) and 30 min post (30P) exercise. We measured serum levels of decorin, interleukin 6 (IL-6), secreted protein acidic and rich in cysteine (SPARC), and oncostatin M (OSM) and cell growth of MDA-MB-231 cells in vitro using real time cellular analysis at each time point. Results: Decorin, IL-6, and SPARC significantly increased (9 to 47%, p < 0.05) from baseline to 0P in both groups. IL-6 remained elevated in both groups at 30 min post-intervention (30P), while OSM levels were elevated only in the RT group at 30P. Between groups, IL-6 was significantly increased in HIIT at 0P (p = 0.001). Cancer cell growth was significantly reduced at 0P and 30P compared to baseline in RT (20 to 21%, p < 0.05) and HIIT (19 to 29%, p < 0.05), with significantly greater effects on MDA-MB-231 cell growth reduction in favour of HIIT at 0P (p = 0.001). Conclusion: A single bout of RT or HIIT can increase levels of anti-cancer myokines and reduce the growth of MDA-MB-231 cells in vitro in survivors of breast cancer, potentially contributing to a lower risk of recurrence. This highlights the importance of exercise as a treatment with promising anti-cancer effects.