Chemotherapeutic Properties of Factors Released from Contracting Skeletal Muscle: Early "Exercise" versus Fatigue

PURPOSEThe purpose of this study is to determine the chemotherapeutic effects of early and late secretions of contracting skeletal muscle on breast cancer cells in vitro. METHODS: MCF7 breast cancer cells were treated with exercise perfusate collected from a rat hemicorpus perfusion in which the hindlimb was electrically stimulated via the sciatic nerve. Study groups (n = 3 wells per group x 3 animals) include perfusate collected from quiescent muscle (NoEx), during the first 5 minutes of contraction, Early Exercise (EEx), during the last 5 minutes of contraction, Fatigue (FTG), as well as normal cell culture media (CON) as a control. Cell counts were taken in triplicate on Day 5 after four days of exposure (refreshed media daily, consisting of 10% perfusate). RESULTS: Average percent reduction in cell counts as compared to NoEx controls were 7% for EEx and 20% for FTG perfusate (P < 0.01 and P < 0.05, respectively).CONCLUSIONThese data support evidence for chemotherapeutic factors being released from contracting skeletal muscle which is more strongly associated with fatigue. These results have important implications for the clinical application of exercise in the prevention and treatment of breast cancer. Future studies will include isolation of candidates and determination of mechanisms of action.This work was funded by the TAMU Cancer Research Center, Cancer Research and Prevention Incentive Grant (SER).

Chemotherapeutic Properties of Factors Released from Contracting Skeletal Muscle: Early "Exercise" versus Fatigue Academic Article