Exercise Hormone May Offer Breast-Cancer Protection

Posted on 22 January 2015
A study suggests that a hormone released after exercise, irisin, may reduce breast-cancer cells and enhance chemotherapy.

A study suggests that a hormone released after exercise, irisin, may reduce breast-cancer cells and enhance chemotherapy.

A hormone released from muscles after vigorous exercise could help to treat or prevent breast cancer, says a study in the February issue of the International Journal of Cancer.

The hormone, called irisin, significantly 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, the study found.

Women who exercise are reported to have a 30% to 40% reduced risk of breast cancer and improved survival if they have the disease, an association that hasn’t been well understood, the researchers said. This study suggests irisin is a possible link between physical activity and breast cancer protection. Its anti-cancer effects may be due to reduced inflammation, the study said.

Experiments at the University of New Mexico in Albuquerque 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 weren’t treated. Malignant cells were also treated with varying concentrations of the chemotherapy drug doxorubicin, with or without irisin.

Irisin treatment reduced the number of malignant cells by 34% compared with untreated cells, but had no effect on nonmalignant cells. Cell migration, the movement of cancer cells to new sites, was reduced by 51%, suggesting irisin may prevent or slow metastasis, researchers said.

Cell death, called apoptosis, was 22 times greater in irisin-treated cancer cells than untreated cells. Adding irisin to doxorubicin significantly increased cancer-cell killing at all concentrations, though cells absorbed less of the chemotherapy drug, the study found. This raises the possibility that a lower, more tolerable dose of chemotherapy could be given to patients, the researchers said.

Irisin is a relatively new discovery first reported in 2012. Previous studies have linked the hormone to better weight control, improved cognition and other health benefits.

Irisin is currently being tested on two aggressive strains of malignant prostate cells and on healthy prostate cells, said the study’s principal investigator, Kristina Trujillo, a research assistant professor in the university’s Department of Biochemistry and Molecular Biology.

Caveat: Irisin hasn’t been tested in animal and human trials.

Source: Wall Street Journal

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