WINSTON-SALEM, NC – January 20, 2021 – Breast cancer is the second most common cancer in women in the United States, and cigarette smoking has been linked to a higher incidence of breast cancer spread or metastasis, bringing the survival rate by 33. lowers% in diagnosis.
While cigarette smoking is known to be linked to cancer, the role of nicotine, a non-carcinogenic chemical found in tobacco, in breast-to-lung metastasis is an area that needs further research.
Scientists at the Wake Forest School of Medicine have now found that nicotine promotes the spread of breast cancer cells to the lungs.
The study will be published in the January 20 online edition of Nature Communications.
“Our data show that nicotine exposure creates an environment in the lungs that is ripe for metastasis growth,” said Kounosuke Watabe, Ph.D., lead author of the study and professor of cancer biology at the Wake Forest School of Medicine, Part by Wake. Forest Baptist Health.
This environment is known as the premetastatic niche that attracts pro-tumor neutrophils, a type of immune cell. The premetastatic niche releases a protein called STAT3-activated lipocalin 2 (LCN2) from the neutrophils to induce metastatic growth.
For the study, Watabe’s team first looked at 1,077 breast cancer patients and found that current or former smokers have a higher incidence of lung metastases than those who have never smoked.
Then, using a mouse model of breast cancer metastases, the researchers discovered that prolonged exposure to nicotine creates an inflammatory microenvironment in the lungs characterized by an influx of activated neutrophils to create a premetastatic niche.
Even after 30 days of smoking cessation, the incidence of distant metastases was not reduced, suggesting a persistent risk for breast cancer patients who are former smokers.
Watabe and colleagues also looked for a drug that could block this buildup of neutrophils and identified salidroside, a natural compound found in the plant Rhodiola rosea. This compound, which has anti-inflammatory, anti-cancer and antiviral properties, significantly reduced the number of protumoral neutrophils and subsequently reduced the incidence of lung metastases in mice.
“Based on these results, breast cancer patients should opt for smoking cessation programs that do not use nicotine replacement products,” said Watabe. “In addition, our results indicate that salidroside could be a promising therapeutic drug to prevent smoking-induced lung metastases in breast cancer, although more research is needed.”
Funding for the study was provided by NIH grants R01CA173499, R01CA185650, R01CA205067, R37CA230451, and T32CA247819.
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