Scientists at The Institute of Cancer Research (ICR), in collaboration with other research teams in the UK, US and Australia, develop a viral therapy able to kill prostate cancer cells, and promote better results when combined with a specific type of radiotherapy.
To develop the therapy, the group of researchers genetically modified a strain of vaccinia virus (the active constituent of the vaccine that eradicated smallpox). The virus was modified to target specifically prostate cancer cells, causing no damage to healthy cells. Then, they tested the viral therapy by infecting human prostate cancer cell lines and in mice models of prostate cancer. The results showed that the virus multiplied specifically among the cancer cells, destroying them from within.
They first tested the modified virus therapy alone; and then they studied it in combination with different types of radiotherapy. The group of researchers found that a combination of their modified vaccinia virus therapy and a form of radiotherapy called radioiodine therapy was more effective for killing cancer cells and slowing tumor growth, than each treatment on their own.
This result is because the researchers designed the virus to make prostate cancer cells display a channel protein on their surface. This protein (called the sodium-iodide symporter) allows iodide ions to travel into cells. Therefore, radioactive iodine ions were able to enter into the prostate cancer cells infected with the virus during radioiodine therapy, killing them.
Today, radioiodine therapy is commonly used to treat thyroid cancers, because thyroid cells naturally have the channel protein on their surface; therefore, they are able to absorb radioactive iodides. This study shows the potential to use radioiodine therapy to treat other cancers by combining it with a viral therapy.
While the research, published in Gene Therapy, is still in an early stage, it opens the door to future clinical trials to test possible treatments mixing viral therapy and radiotherapy to destroy cancer cells.
Source: The Institute of Cancer Research
