Scientists have created artificial ‘designer’ viruses that can target cancer by alerting the body’s immune system and sending killer cells to fight tumours. The findings, published in the journal Nature Communications, may pave the way for novel cancer treatments. Most cancer cells only provoke a limited reaction by the immune system – the body’s defence mechanism – and can thus grow without appreciable resistance.
By contrast, viral infections cause the body to release alarm signals, stimulating the immune system to use all available means to fight the invader. Immunotherapies, used to treat cancer for many years, “disinhibit” the body’s defence system and thus strengthen its half-hearted fight against cancer cells. Stimulating the immune system to specifically and wholeheartedly combat cancer cells, however, has remained elusive. Researchers at the University of Geneva (UNIGE) and the University of Basel in Switzerland have now succeeded in manufacturing innovative designer viruses for that purpose.
They built artificial viruses based on lymphocytic choriomeningitis virus (LCMV), which can infect both rodents and humans. Although they were not harmful for mice, they release the alarm signals typical of viral infections. The researchers also integrated certain proteins into the virus that are otherwise found only in cancer cells. Infection with the designer virus enabled the immune system to recognise these cancer proteins as dangerous.
The unique combination of alarm signals and the cancer cell protein stimulated the immune system to create a powerful army of cytotoxic T-lymphocytes, also known as killer cells, which identified the cancer cells through their protein and successfully destroyed them.The treatments available to cancer patients have developed enormously in the last few years. However, as the researchers report, current treatments are still inadequate in combating many forms of cancer. “We hope that our new findings and technologies will soon be used in cancer treatments and so help to further increase their success rates,” said Doron Merkler from UNIGE.