The fight against cancer can take many forms and the way this disease spreads is one of its pillars. Cold Spring Harbor Laboratory Cancer Center researchers questioned the effects of chronic stress (a state of stress prolonged over time) in the spread of cancer. They found that chronic stress increases lung metastases from cancer cells by 2-4 times in mice. Their results are published in the journal Cancer Cell.
Cancer: chronic stress increases the risk of metastases
As a preamble to their research, the authors emphasize that “THE chronic stress is associated with a increased risk of metastases and to a low survival in cancer patients, but the reasons are unclear.” To try to explain it, the team of scientists used mice suffering from lung cancer. After eliminating the growing tumors, they subjected the rodents to stressful situations.
“The team saw this frightening increase in metastatic lesions in these animals. Metastases increased fourfold”, summarizes Assistant Professor Mikala Egeblad of the Cold Spring Harbor Laboratory in a press release. But how can we explain this sharp increase? According to the researchers, the stress hormones (called glucocorticoids), had a impact on the white blood cells responsible for the body’s defense reactions known as neutrophils.
Neutrophils then form sticky, web-like structures called NETs (neutrophil extracellular traps) that make body tissues more susceptible to metastasis. If they usually play a role in defending the body against microorganisms, in the context of cancer, NETs create an environment favorable to metastases.
Chronic stress: researchers call for reducing it alongside treatment and prevention of cancer
To be certain, the researchers carried out three experiments on mice. First, they eliminated neutrophils from the mice using antibodies. Secondly, they destroyed the mice’s NETs using drug treatments. Thirdly, they used mice whose white blood cells were not impacted by the stress hormone. Each test gave similar results. “Stressed mice no longer developed metastases”summarizes in the press release Xue-Yan He, former post-doctoral fellow in the laboratory of Mikala Egeblad, assistant professor at Cold Spring Harbor Laboratory (CSHL).
But chronic stress could promote metastases before the appearance of cancer. Indeed, “our data show that glucocorticoids released during chronic stress cause the formation of NETs and establish a microenvironment favoring metastasis”, write the researchers. In other words, chronic stress “almost prepares your tissues for cancer”, Assistant Professor Mikala Egeblad explains in the press release.
Also, researchers call for the stress reduction either included in the supported patients fighting cancer, but also in cancer prevention. In addition, they believe that future treatment to prevent the formation of NETs could slow the spread of cancer in patients before it metastasizes.
Sources:
- Chronic stress increases metastasis via neutrophil-mediated changes to the microenvironment – Cancer Cell
- Chronic stress spreads cancer … here’s how – Cold Spring Harbor Laboratory (CSHL) (press release)
- Cancer in figures (France and world) – ARC Foundation for Cancer Research