A drug against breast cancer to treat myopathies ⋅ Inserm, From science to health

Widely used in the treatment of certain breast cancers, tamoxifen has already shown its ability to improve muscle cell function in two types of myopathies, including Duchenne. Today, a new study confirms the potential interest of this drug for the management of a third family of neuromuscular diseases: centronuclear myopathies. The hypothesis of a universal use of anti-cancer, for all myopathies, is more and more credible…

Myopathies include more than 200 neuromuscular diseases, most of which are of genetic origin. All are characterized by impaired muscle function, but they are distinguished by different mutations and pathophysiological mechanisms. At the Institute of Genetics and Molecular and Cellular Biology in Strasbourg, Jocelyn Laporte’s team is studying two families: centronuclear myopathies linked to gene mutations DNM2 or BIN1and myotubular myopathies linked to a mutation of MTM1. « The cellular abnormalities caused by these different mutations result in excessive activity of dynamin 2, a protein in responsible for the reorganization of the membrane of muscle cells. This phenomenon limits the ability of muscle cells to contract. », explains the researcher.

With his team, he has just shown that the administration of tamoxifen, an anti-cancer drug used in breast cancer, improves muscle contractility in an animal model of centronuclear myopathy. ” This was a so-called repositioning study, he continues. This consists of studying a molecule already on the market to find out if it could be effective in other diseases. This approach makes it possible to identify new treatments more quickly than by the traditional route, since their toxicity in humans is already known.

Encouraging clinical results

Tamoxifen has anti-estrogenic activity in breast tissue, but it also appears to have a favorable effect on muscle cell function. A few years ago, this particularity motivated researchers to evaluate the effect of tamoxifen in an animal model of Duchenne muscular dystrophy, the most common genetic muscle disease, in which a disturbance in the cohesion of muscle tissue leads to the progressive muscle degeneration. “ The convincing results that have been obtained have led to the establishment ofa clinical trial