Tumours often contain areas of oxygen-deficient tissue that frequently withstand conventional therapies. This is because the drugs applied in tumours require oxygen to be effective. An international research team has developed a novel mechanism of action that works without oxygen: polymeric incorporated nanocatalysts target the tumour tissue selectively and switch off the glutathione that the cells need to survive. The team published their findings in the journal Nature Communications.
Why tumours shrink but don’t disappear
Study leader Dr Johannes Karges from Ruhr University Bochum, Germany, explained: “As tumours grow very quickly, consume a lot of oxygen and their vascular growth can’t necessarily keep pace, they often contain areas that are poorly supplied with oxygen.” These areas, often in the centre of the tumour, frequently survive treatment with conventional drugs, so that the tumour initially shrinks but doesn’t disappear completely. This is because the therapeutic agents require oxygen to be effective.
The mechanism of action developed by Karges’ team works without oxygen. “It’s a catalyst based on the element ruthenium, which oxidises the naturally present glutathione in the cancer cells and switches it off,” explains Karges. Glutathione is essential for the survival of cells and protects them from a wide range of different factors. If it ceases to be effective, the cell deteriorates.
Compound accumulates in tumour tissue
All cells of the body need and contain glutathione. However, the catalyst has a selective effect on cancer cells as it is packaged in polymeric nanoparticles that accumulate specifically in the tumour tissue. Experiments on cancer cells and on mice with human tumours, that were considered incurable, proved successful. “These are encouraging results that need to be confirmed in further studies,” concludes Johannes Karges. “Still, there’s a lot of research work to be done before it can be used in humans.”
Source: Ruhr-University Bochum
