A molecule that could fully reverse the devastating muscle loss that often accompanies advanced cancer in mice has been developed by scientists.
The molecule blocks the activity of a key muscle-limiting protein called myostatin by acting as a decoy.
Instead of myostatin binding to its normal receptor and triggering muscle wastage, it is 'mopped up' by binding to the decoy molecule instead.
Muscle wasting - called cachexia - is thought to account for about 30 percent of deaths in patients with cancer, but how exactly cachexia is spurred by cancer - or indeed exactly how it leads to a patient's decline - isn't known.
It is thought that several molecular pathways work in tandem, "activating an axis of evil to control muscle mass in a negative way", said H. Q. Han, lead author of the study and scientific director of the metabolic disorders division at Amgen, a biotechnology company in Thousand Oaks, California.
The researchers wanted to find the dominant pathway responsible for cancer cachexia, and then design a way to block it in order to treat patients.
Several studies have shown that blocking the myostatin pathway can promote muscle growth, said Han, and some have shown that a molecule closely related to myostatin, called activin A, becomes more abundant in patients with some cancers.
"We examined a large random collection of cancer cell lines in vitro, and found that one-third of them secreted large amounts of activin A. This led us to believe that activin A must have some systemic function when overproduced in a cancer setting," Nature quoted Han as saying.