Downward-facing mouse: Stretching reduces tumor growth in mouse model of breast cancer

May 22, 2018, Brigham and Women's Hospital

Many cancer patients seek out gentle, movement-based stretching techniques such as yoga, tai chi and qigong, but does stretching have an effect on cancer? While many animal studies have attempted to quantify the effects of exercise on the disease, results have been mixed. Furthermore, studies in animals involve levels of vigorous exercise that can be difficult for cancer patients. Investigators at Brigham and Women's Hospital, in collaboration with colleagues at Dana-Farber Cancer Institute, have conducted new research in a preclinical model to specifically study whether stretching can affect tumor growth. Using a mouse model of breast cancer and a gentle stretching technique, the team evaluated tumor growth as well as changes in molecular signals of immune response and inflammation resolution. Their results appear in Scientific Reports.

"We know, generally, that physical activity is beneficial in but not why that is. Some animal models of exercise show benefit, others don't," said co-corresponding author Helene Langevin, MD, director of the Osher Center for Integrative Medicine at Harvard Medical School and Brigham and Women's Hospital. "Gentle stretching is something that many patients not only can do but enjoy doing. We wanted to develop a preclinical model that could help us study the effects of stretching on and, if safe and effective, be translated into a regimen for humans."

Langevin and colleagues used a well-established protocol for stretching in mice in which the animals are held by the tail and gently lifted, allowing their front paws to grasp a bar. With minimal training, mice can hold this position without struggling for 10 minutes. The team studied 66 mice, which were randomized to a "stretch group" that received daily stretching for four weeks or to a "no-stretch group," which did not. Mice in both groups were injected with breast cancer cells into their mammary tissue. After four weeks, tumor volume was 52 percent smaller in the stretch group compared to the no-stretch group without any other form of treatment.

"These results open myriad new avenues of research," said co-corresponding author Jean J. Zhao, Ph.D., professor of biological chemistry and molecular pharmacology at Harvard Medical School and Dana-Farber Cancer Institute. "There is still so much we don't understand in terms of how stretching reduces tumor growth. Understanding these mechanisms could help us develop more effective therapies against and potentially other cancer types."

The team continued its investigations to try to shed light on why tumor growth slowed in the mice in the stretch group. Hypothesizing that stretching may reinvigorate T-cells to fight against cancer, the team measured the levels of molecular markers that signal the activation of an immune response. They found that stretching reduced levels of PD-1, an important immune "check point" that blocks the body's ability to fight cancer cells. The team also measured levels of specialized pro-resolving mediators (SPMs), molecules that promote the natural resolution of inflammation. They found that levels of SPMs were significantly greater in the stretch group than a non-stretch group.

"Inflammation is a double-edged sword in cancer," said Langevin. "Although it is an essential component of all immune responses, it needs to be limited both in location and duration. Finding changes in both markers of the immune system ramping up its attack on cancer cells as well as markers of inflammation resolution suggests a potentially important link between these two areas of inquiry."

The authors caution that this preclinical research in no way suggests that cancer patients should stretch instead of receiving traditional cancer treatment. The research is at an early, investigative stage, and before it can be translated into a human protocol for clinical trials, further preclinical safety testing and dosage testing is needed. The team also wants to look at animal models with more advanced cancer that could metastasize to understand whether stretching may increase or decrease the spread of the disease.

Explore further: Researchers discover new approach to stimulate an immune response against tumor cells

More information: L. Berrueta et al, Stretching Reduces Tumor Growth in a Mouse Breast Cancer Model, Scientific Reports (2018). DOI: 10.1038/s41598-018-26198-7

Related Stories

Researchers discover new approach to stimulate an immune response against tumor cells

January 30, 2018
New drugs that activate the immune system to target cancer cells have improved the lives of many patients with cancer. However, immunotherapies are not effective in all patients, and the success of these therapies depends ...

Dulling cancer therapy's double-edged sword

January 17, 2018
Researchers have discovered that killing cancer cells can actually have the unintended effect of fueling the proliferation of residual, living cancer cells, ultimately leading to aggressive tumor progression.

Study reveals cancer therapy's double-edged sword... and how to blunt it

November 30, 2017
Researchers from Harvard Medical School and the Institute of Systems Biology have discovered that the remains of tumor cells killed by chemotherapy or other cancer treatments can actually stimulate tumor growth by inducing ...

Metformin could one day be used to treat malignant tumors

January 16, 2018
A*STAR researchers have provided strong evidence, using patient tumor grafts, that metformin, a common diabetes drug, might help fight colorectal cancer in humans.

Cholesterol byproduct hijacks immune cells, lets breast cancer spread

October 12, 2017
High cholesterol levels have been associated with breast cancer spreading to other sites in the body, but doctors and researchers don't know the cause for the link. A new study by University of Illinois researchers found ...

Cell cycle-blocking drugs can shrink tumors by enlisting immune system in attack on cancer

August 16, 2017
In the brief time that drugs known as CDK4/6 inhibitors have been approved for the treatment of metastatic breast cancer, doctors have made a startling observation: in certain patients, the drugs—designed to halt cancer ...

Recommended for you

Mutant cells colonize our tissues over our lifetime

October 18, 2018
By the time we reach middle age, more than half of the oesophagus in healthy people has been taken over by cells carrying mutations in cancer genes, scientists have uncovered. By studying normal oesophagus tissue, scientists ...

Study involving hundreds of patient samples may reveal new treatment options of leukemia

October 17, 2018
After more than five years and 672 patient samples, an OHSU research team has published the largest cancer dataset of its kind for a form of leukemia. The study, "Functional Genomic Landscape of Acute Myeloid Leukemia", published ...

A 150-year-old drug might improve radiation therapy for cancer

October 17, 2018
A drug first identified 150 years ago and used as a smooth-muscle relaxant might make tumors more sensitive to radiation therapy, according to a recent study led by researchers at The Ohio State University Comprehensive Cancer ...

Loss of protein p53 helps cancer cells multiply in 'unfavourable' conditions

October 17, 2018
Researchers have discovered a novel consequence of loss of the tumour protein p53 that promotes cancer development, according to new findings in eLife.

New method uses just a drop of blood to monitor lung cancer treatment

October 17, 2018
Dr. Tasuku Honjo won the 2018 Nobel Prize in physiology or medicine for discovering the immune T-cell protein PD-1. This discovery led to a set of anti-cancer medications called checkpoint inhibitors, one of the first of ...

Researcher fighting breast cancer with light therapy

October 17, 2018
When treatment is working for a patient who is fighting cancer, the light at the end of the tunnel is easier to see.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.