Introduction and aims
Post-exercise human serum treatment can exhibit anti-viability properties in various cancer cell lines. However, whether the presence and/or magnitude of the effect differs in different participant populations is yet to be established. The aim of this study was to characterise baseline differences in serum-stimulated colorectal cancer cell viability and the acute exercise-induced response in males and females with varying levels of cardiorespiratory fitness (CRF).
Methods
Forty-one participants (13 female) were stratified by maximal exercise test-derived VO2peak into high (n = 20) and low CRF (n = 21) and completed two experimental trials in a randomised crossover design: (1) 30-min moderate-intensity aerobic exercise and (2) 30-min seated rest. Serum samples were collected before (pre), immediately after (post0), and 60-min after (post60) each trial and used to treat the human colorectal cancer cell line Caco-2 for 48 h, with cell viability assessed by MTT assay. Data were analysed using linear mixed-effects models.
Results
Exercise-induced alterations in Caco-2 cell viability were, at least in part, modulated by CRF and sex. Specifically, exercise serum significantly reduced cell viability compared with no-exercise control serum when derived from individuals with high (post0: -6.26%, P = 0.027; post60: -8.86%, P = 0.010) but not low CRF (post0: -3.19%, P = 0.21; post60: -7.71%, P = 0.085), and when derived from males (post0: -5.59%, P = 0.014; post60: -10.41%, P = 0.001) but not females (post0: -2.68%, P = 0.39; post60: -3.46%, P = 0.63). At rest, there were no CRF (P = 0.78) or sex differences (P = 0.90) in the effects of basal human serum on Caco-2 cell viability.
Conclusion
Acute aerobic exercise-induced changes in the circulating milieu can have suppressive effects on colorectal cancer cell viability in vitro, which may be CRF- and sex-dependent. These findings provide the first insights into the role of individual characteristics in determining the effects of exercise on colorectal cancer cells, with potential implications for increasing the precision of exercise recommendations for colorectal cancer risk reduction.