Does Training Status Influence Myokine Levels and Cancer Cell Survival In Vitro? Effects of a Single Bout of Exercise in Breast Cancer Survivors

PURPOSE: We investigated the impact of training status (untrained versus trained) on acute myokines with anti-cancer properties and cancer cell suppression before (untrained) and after (trained) a 12-week resistance training (RT) vs high-intensity interval training (HIIT) program. METHODS: Twenty-eight breast cancer survivors completed a single bout (defined as one complete exercise session) of RT or HIIT before and after a 12-week structured RT or HIIT program. Blood was collected before, immediately and 30 minutes after each acute RT or HIIT session to measure serum levels of myokines (decorin, interleukin 6 [IL-6], secreted protein acidic and rich in cysteine [SPARC], and oncostatin M [OSM]) and MDA-MB-231 cell growth in vitro. RESULTS: The acute session after a 12-week RT or HIIT significantly increased myokine levels compared to the acute session pre-training (p < 0.05), with elevations observed for IL-6 and OSM in RT (generalized eta squared [ges] = 0.029 to 0.131) and decorin and OSM in HIIT (ges = 0.016 to 0.031). The acute exercise session performed after 12 weeks of RT or HIIT induced significantly greater cancer-suppressive effects on MDA-MB-231 cells in vitro compared to the pre-training session (p < 0.05), with inhibitory effects observed in RT (ges = 0.156) and HIIT (ges = 0.052). CONCLUSIONS: A single exercise bout, whether RT or HIIT, elevates myokines and suppresses breast cancer cell growth in vitro, with greater effects after 12 weeks of training (trained individuals). RT and HIIT showed comparable outcomes, highlighting that regular exercise enhances myokines with anti-cancer properties and reduces in vitro cell growth.