According to a study, a hormone, irisin, released from muscles after vigorous exercise could help treat or prevent breast cancer.
Irisin was newly discovered in 2012. Previous studies linked the hormone to better weight control, improved cognition and other health benefits.
Women who exercise tend to have a 30% -40% reduced risk of breast cancer and improved survival if they have the disease. Researchers do not particularly understand the association. The study suggests that the hormone may attribute its anti-cancer effects to reduced inflammation.
The study was released in the February issue of the International Journal of Cancer.
Experiments tested genetically engineered irisin on aggressive breast-cancer cells similar to cells found in triple negative breast cancer, a particularly deadly form of the disease, and on nonmalignant breast cells. Varying doses of irisin were added to cell cultures for 24 hours; control cultures were not treated. Malignant cells were also treated with varying concentrations of a chemotherapy drug, doxorubicin, with or without irisin.
The hormone reduced the number of aggressive breast-cancer cells in laboratory cultures and enhanced the effects of a chemotherapy drug commonly used to treat breast cancer.
Irisin treatment reduced the number of malignant cells by 34% compared with untreated cells, but had no effect on nonmalignant cells. Cell migration was reduced by 51% which suggests that irisin may prevent or slow metastasis.
Cell death was 22 times higher in irisin-treated cancer cells than untreated cells. By adding irisin to doxorubicin significantly increased cancer-cell killing at all concentrations, however the cells tended to absorb less of the chemotherapy drug. This creates the possibility that a lower, more tolerable dose of chemotherapy could be given to patients.
Irisin is currently being tested on two aggressive strains of malignant prostate cells and healthy prostate cells.
However, irisin has yet to be tested in animal or human trials.