Severity of muscle wasting associated with tumor type, size and location in mice – Zoo House News

About 80% of people with cancer experience significant muscle wasting or loss of muscle tissue, and 30% of these patients die from the disease. New research in mice shows that the severity of muscle wasting is related to the type, size and location of the tumor.

“Muscle wasting, rather than the tumor itself, is often the killer,” said Gustavo Nader, associate professor of kinesiology at Penn State University. “Therefore, it is important to study what is happening at the cellular level in skeletal muscle, which may contribute to the wasting problem.”

Nader’s previous research on ovarian cancer showed that muscle wasting was linked to reduced production of ribosomes — or particles in the cell that make proteins. However, relatively little is known about the mechanisms that drive muscle protein synthesis and muscle wasting in cancer patients.

In new research, published in two articles appearing in the same issue of the Journal of Applied Physiology, the team examined the mechanisms involved in muscle wasting in lung cancer and colon cancer in mice. The researchers found that tumor type, size and location affected the severity of muscle wasting through different mechanisms.

In the lung cancer study, the team looked at the effects of two different types of lung cancer-derived tumors – LP07 and Lewis lung carcinoma (LLC). Tumor growth caused significant muscle weakness in mice with the LP07 tumor type that was also associated with a reduction in ribosome production, while muscle wasting in the LLC tumor type caused muscle wasting but did not cause weakness or decrease ribosome levels.

In the colon cancer study, the team looked at two types of colon tumors – HCT116 and C26 – and tested them using two models to define the role of tumor burden in muscle wasting. Tumor burden is the number of cancer cells, the size of a tumor, the amount of cancer in the body, or the severity of the disease associated with the tumor. The results suggest that the location of the tumor is an important factor in determining the severity of muscle wasting, but that it also depends on the type of tumor.

“There are no effective treatments for muscle wasting in cancer patients,” Nader said. “We are beginning to understand how different tumors cause muscle wasting, which is crucial because cancer treatments are less effective in patients with low muscle mass.”

The Penn State team worked with David Waning from Hershey Medical Center, Esther Barreiro from Universitat Pompeu Fabra in Barcelona and Andrea Bonetto from Indiana University. Research at the Nader lab is supported by the National Institutes of Health.

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Materials provided by Penn State. Originally written by Sara LaJeunesse. Note: Content can be edited for style and length.