Could Physical Activity Help Control Cancer?

This is an exciting time for cancer research. From targeted immunotherapies to the increasingly important role of genetic testing in tailoring screening and treatment, there is a lot to be hopeful about.

In my last post, I discussed a study using a novel research method, Mendelian randomization, that provides a more robust understanding of the benefit of vigorous physical activity in reducing breast cancer risk. Recently, I had the privilege to sit down with Dr. Jinming Gao, the Elaine Dewey Sammons Distinguished Chair in Cancer Research in the Simmons Comprehensive Cancer Center at UT Southwestern Medical Center, to discuss a recently published finding in the journal Nature Communications.

Effect of Lactate on Tumor Growth

This study examined the effect of lactate on tumor growth. Lactate is the substance that your cells produce as your body is turning food into energy. It is also produced by your cells during strenuous exercise. In the study, mice with melanoma or colon adenocarcinoma cell lines were injected with either lactate or glucose. The results were surprising—the mice injected with lactate had significantly reduced tumor growth compared to those injected with glucose. When the researchers added an immune checkpoint inhibitor—a type of cancer treatment that helps the body recognize and attack cancer cells—50 percent of the mice were tumor free.

The key seems to be in how lactate assists T cells. T cells are immune cells that help fight cancer. In a tumor, however, T cells become dysfunctional and lose their ability to fight cancer cells. As Dr. Gao explains, “We found this novel mechanism that lactate is making the T cells younger. It’s keeping the T cells rejuvenated from getting exhausted by the cancer cells through acidity, cytokines, or other various reasons.”

Next steps for Dr. Gao and his colleagues are to validate these results in human tumors that have been explanted—living tissue that has been transferred to an artificial medium for tissue culture. “We can take human tumor samples and inject it with lactate and see whether the tumor-infiltrating T cells become rejuvenated. We can also try to give patients Ringer’s solution—a lactate solution that is used in the clinic—and monitor patient T cell changes over time, or combine it with a checkpoint inhibitor to see whether that improves patient response.”

Implications for Physical Activity

Of course, I wanted to know how this research may translate to behavior. Does this provide more evidence to support the importance of physical activity? Dr. Gao notes, “I love to run, and this study now gives that new meaning. It may not be the complete story, but at least on the T cell and the immune cell side, every time I run, I know all this lactate that is generated by running is keeping my T cells from getting exhausted.”

There is so much to be learned about treating cancer, and these new findings add a critical piece to the puzzle. These findings also shed light on further understanding the protective effects of physical activity in cancer. Because lactate is naturally produced by the body while exercising, it may be that this is helping T cells stay healthy to more effectively fight cancer cells.

Have you been meaning to start moving more? This may be the motivation you need! Try these ideas for increasing your level of physical activity.