A new study has found that an antidepressant widely prescribed may treat a childhood cancer known as childhood sarcoma, at least in experiments with mice and laboratory cells. The findings, taken from researchers at the Karolinska Institutet in Sweden and the MD Anderson Cancer Centre in Texas, give rise to hope for new therapeutic methods for this disease. The analysis is published in Cancer Science, a journal.

“Although this study was conducted in mice and we do not yet know how the results are translatable to humans, it gives us hope that repurposing common medicines for young cancer patients will desperately require better treatment options,” says first author of the study, Caitrín Crudden, a former PhD student in the group of receptor signalling pathology at the Karolinska Institutet’s Department of Oncology-Pathology. Two large classes of cell surface receptors, the so-called G protein-coupled receptors (GPCRs) and the receptor tyrosine kinases were examined in the study for similarities (RTKs). In order to treat conditions such as allergies, asthma, depression, anxiety and hypertension, GPCRs are targeted by more than half of all developed medications but have not been commonly used to treat cancers so far.

The researchers treated childhood (Ewing) sarcoma cells and mouse models with paroxetine, an antidepressant drug that impairs a receptor for serotonin reuptake that is part of the GPCR family, to test their hypothesis. They found that the number of IGF1R receptors on malignant cells was significantly reduced by this drug and thus suppressed tumour development. The scientists also disclosed the molecular process behind this cross-targeting.

“We have developed a novel strategy to control the activity of these tumour-driving receptors by striking the GPCRs,” says Leonard Girnita, a researcher in the Department of Oncology-Pathology, Karolinska Institutet, and principal investigator of the study. “To our knowledge, this represents a new paradigm for the entire class of cancer-relevant RTKs and could be used as a starting point for the rational design of specific therapeutics in virtually any pathological conditions. This is especially important considering the huge number of GPCR-targeting medicines already in clinical use and with low toxicity.”Next, the researchers plan to develop their strategy to selectively cross-target multiple RTKs and to verify their findings in a clinical setting.