A single bout of physical activity could fill the bloodstream with cancer-busting allies.
In an experiment involving 32 breast cancer survivors, a 45-minute session of either resistance training or high-intensity interval training resulted in a surge of messenger proteins in the blood.
When these players, called myokines, were introduced to breast cancer samples in the lab, they suppressed the growth of tumors by up to 30 percent.
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“The results from the study show that both types of exercise really work to produce these anti-cancer myokines in breast cancer survivors,” says lead author and exercise researcher Francesco Bettariga from Edith Cowan University in Australia.
“The results from this study are excellent motivators to add exercise as standard care in the treatment of cancer.”
The current experiments tested the blood of participants for myokines before exercise, immediately following, and 30 minutes after.
Those allocated to the resistance training group performed chest presses, seated rows, shoulder presses, lat pulldowns, leg presses, leg extensions, leg curls, and lunges. Those allocated to the high-intensity interval training, meanwhile, performed sets on the stationary cycle, treadmill, rower, and cross-trainer.
Ultimately, these exercises drove a short-term uptick in three types of myokine: decorin, IL-6, and SPARC.
Skeletal muscle secretes myokines into the bloodstream in response to exercise to stimulate growth or burn fat, though the proteins are known to also have anti-inflammatory effects. Preclinical and experimental studies have shown these effects suppress growth in different tumors, including breast cancer. Until now, it was not known if the same phenomenon occurred among cancer survivors.
Triple negative cancer cells which form certain kinds of breast cancer lack hormone receptors, so they were not expected to respond to hormonal fluctuations linked to exercise. Nevertheless, Bettariga and colleagues found that the cancer cells were impacted by exercise-associated myokines in the lab.
The findings join a growing number of studies that suggest myokines may have the potential to fight cancer.
“Our findings demonstrate that both resistance training and high-intensity interval training elicit acute changes in circulating myokines and reduced cancer cell growth, which may contribute to proposed biological pathways involved in cancer control,” conclude the authors; “however, further research is needed to determine the long-term relevance of these responses for disease recurrence in breast cancer survivors.”
The study was published in Breast Cancer Research and Treatment.
