In Vitro HUVEC model of chronic exercise protection of vascular endothelial toxicity of FEC-T chemotherapy treatment for breast cancer using ex vivo serum preconditioning

Chemotherapy treatments for breast cancer are toxic to the cardiovascular system and can lead to the development of cardiovascular disease. As the first point of contact with chemotherapy drugs, it is important to consider the role of the vascular endothelium in the development of cardiovascular toxicity and to identify potential therapeutics to protect against this toxicity. Exercise has been recognised as a possible adjunct therapy to counteract the detrimental effects of chemotherapy on the endothelium. Therefore, the aim of this study is to determine if there are protective effects of chronic exercise training on chemotherapy-induced vascular toxicity. Methods: Human umbilical vein endothelial cells (HUVECs) were cultured in endothelial cell growth medium supplemented with 5% serum from healthy trained (n=3) and untrained (n=3) females. After 24-hours of serum preconditioning, HUVECs were exposed to physiological concentrations of FEC-T (5-fluorouracil, epirubicin, cyclophosphamide, and docetaxel) drugs. At appropriate time-points (0-, 3-, 4-, 6-, 12-, 24-, and 48-hours), the effects of exercise and chemotherapy on HUVEC viability, apoptosis and eNOS activity were measured using intracellular flow cytometry. Results: All FEC-T drugs increased cell death, caspase-3 activity, and annexin-V expression, and reduced eNOS and Phospho-eNOS expression, in a dose-dependent manner. Preconditioning HUVECs with serum from exercise trained females showed a reduction in cell death, caspase-3, and annexin-V expression, when compared to untrained serum, reaching significance in 5-FU (viable HUVECs for trained: 73.08±6.96% vs untrained: 53.52±2.64%, p=0.03; caspase-3 expression for trained: 27.23±6.35% vs untrained: 59.77±8.95%, p=0.04) and epirubicin (caspase-3 expression for trained: 34.10±5.44% vs untrained 51.20±1.31%, p=0.04; annexin V expression for trained: 13.03±0.79% vs untrained: 17.73±1.11%, p=0.03). There was no between-group difference for eNOS and Phospho-eNOS expression. Conclusions: Our results confirm that FEC-T drugs commonly used in breast cancer treatment cause death and dysfunction of endothelial cells in a dose-dependent manner. For the first time, we have shown that this endothelial cell damage may be affected by training status.