Exercise decreases the risk of breast cancer, and some research suggests it may lengthen survival. A recent cell study may help explain the link, showing that a protein potentially released when exercising prevents breast cancer cell growth.
The new study was published in the International Journal of Cancer and focuses on the protein irisin.
Research on how our body produces irisin is ongoing, but it is thought that skeletal muscle cells release irisin following exercise. Some studies also show that blood irisin levels increase with lean body mass and exposure to the cold. Due to earlier studies suggesting irisin has an effect on cellular metabolism, this study’s authors hypothesized that irisin may affect breast cancer cell growth.
The authors found that treating aggressive breast cancer cells with irisin led to decreased cell number and migration, and increased cell death, without affecting the non-cancerous cells. Irisin had no effect on breast cancer cells that were not aggressive.
When the authors investigated the effect of irisin with a chemotherapeutic agent -- Doxorubicin (Dox) - -they found irisin enhanced Dox’s ability to kill aggressive breast cancer cells. And irisin decreased Dox uptake in the aggressive cancer cells. The authors speculate that irisin may enhance the efficacy of Dox, despite aggressive cancer cells taking up less. Irisin was also found to enhance Dox’s ability to kill a non-aggressive breast cancer cells, but it did not affect Dox’s toxicity to non-malignant breast cells.
The authors speculate that although results are still preliminary, irisin may allow for reduced doses of chemotherapeutic agents like Dox, improving patient tolerance to treatment and prognosis.
Nicholas P. Gannon, Roger A. Vaughan, Randi Garcia-Smith, Marco Bisoffi and Kristina A. Trujillo. Effects of the exercise-inducible myokine irisin on malignant and non-malignant breast epithelial cell behavior in vitro. Int J Cancer. 2015 Feb 15;136(4):E197-202. doi: 10.1002/ijc.29142.