Scientists have discovered that aging muscle may contribute to cancer growth by releasing fewer extracellular vesicles, tiny particles that cells use to communicate with one another.
Their study also found that composition of these particles changes with age, weakening protective signals that help suppress tumor development.
Encouragingly, exercise appears to restore this protective function.
Published in Nature Communications, the findings offer fresh insights into healthy aging and cancer prevention, as well as point to potential biomarkers and therapies tailored to older adults.
The effects of aging muscle are especially evident in sarcopenia, a condition marked by loss of skeletal muscle mass and strength as one gets older.
Working with collaborators from Singapore General Hospital and Cardiff University, the scientists found that sarcopenic muscle secretes fewer extracellular vesicles. As muscle ages, these vesicles also contain lower levels of miR-7a-5p—a microRNA or a very small RNA molecule that helps regulate gene expression by controlling the types and amounts of proteins cells produce. miR-7a-5p plays a role in restraining tumor growth.
Importantly, the team also discovered that the release of extracellular vesicles from muscle is controlled by a biological pathway that declines with age but can be reactivated through exercise.
“Muscle cells use extracellular vesicles to send messages and influence how other cells behave, but exactly how these messages are delivered and received is not fully understood,” says Assistant Professor Tang Hong-Wen from the Cancer & Stem Cell Biology Signature Research Programme at Duke-NUS Medical School, and senior author of the study.
“Our research uncovers this hidden process, showing that as muscles weaken with age, these signals can change in ways that can promote tumor growth.”
“Clinically, we observe an association between advanced cancer and low muscle mass. This is a novel study which illustrates how healthy muscle can potentially inhibit tumor growth,” says Kenon Chua, a consultant in the orthopedic surgery department at Singapore General Hospital and one of the authors of the study.
“We observe that healthy muscles secrete many physiologically important molecules. With advanced age, it is even more important to engage in regular resistance and aerobic exercises in order to maintain healthy muscle volume. This is important not only for function and mobility, but also for general health,” says Chua.
“We hope that the insights from our research can help us develop new targeted therapies for our patients; as well as convince more people of the benefits of regular exercise.”
With their study, the scientists have established a direct biological link between aged muscle and tumor growth. Together, the findings reveal a muscle-to-tumor communication pathway that could be targeted to develop new therapies aimed at preventing cancer progression.
“This study opens new avenues for therapeutic strategies to preserve muscle health and reduce cancer risk, while also underscoring the importance of physical activity in aging,” says Professor Lok Shee Mei, interim vice-dean for research at Duke-NUS Medical School.
“We hope that policymakers in Singapore and across the region will use this evidence to support greater investment in healthy aging programs and exercise-based interventions.”
Next, the scientists plan to validate their findings in human samples and determine whether extracellular vesicles—particularly the miR-7a-5p they carry—could serve as biomarkers for assessing cancer risk associated with sarcopenia.
This research was supported by the Singapore Ministry of Education; the Diana Koh Innovative Cancer Research Award; National Academy of Medicine; and the National Research Foundation, Singapore.
Source: Duke-NUS
