Experts discover how cancer cells protect themselves from viruses

Experts discover how cancer cells protect themselves from viruses. Researchers at the Francis Crick Institute have discovered how cancer cells evade the viruses that aim to kill them. By identifying the mechanism that protects cancer cells, the research may ultimately lead to improved viral treatments.

Oncolytic viruses, which are not harmful to healthy cells, seek out and infect cancer cells. As the cells are destroyed, the virus releases new infectious particles to attack the remaining tumor.

“These viruses prefer to target cancer cells over healthy cells, which has made them of interest for scientists over the last few decades,” said study co-lead author Antonio Rullan.

“However, much more remains to be understood about how they interact with tumors and the immune system.”

The viruses are sometimes used to activate an immune response against tumors, but the treatments have not been widely effective. 

To investigate, the researchers took a close look at the environment surrounding a tumor and examined how cancer cells interact with neighboring cells. The study was focused primarily on cancer-associated fibroblasts (CAFs), which are known to play a key role in the growth and spread of cancer.

The experts noticed that direct contact between cancer cells and CAFs triggered inflammation. This signaled the surrounding tissue and made it difficult for the viruses to gain access to the cancer cells.

The study revealed that the protective inflammatory response is initiated when small amounts of cytoplasm, or cancer cell fluid, are passed to the CAFs. The fibroblasts alert nearby cells to release molecules called cytokines that cause inflammation.

“This process only occurs when cancer cells and fibroblasts are in direct contact with each other. In healthy tissue, this type of inflammatory response would only happen during injury, as there is usually a membrane keeping them apart,” explained study co-author Erik Sahai. “This is an excellent example of the way cancer hijacks our body’s protective mechanisms for its own gain.”

In cell cultures and tumors grown in the lab, the researchers blocked the signaling pathway that causes the inflammatory response. As a result, the cancer cells became more vulnerable to oncolytic viruses.

The experts hope the findings may help to develop a treatment that will inhibit inflammation and allow oncolytic viruses to effectively target cancer cells.

“If we can more fully understand how cancer cells protect themselves from oncolytic viruses and find effective ways to stop these protective mechanisms, these viruses could become a more powerful tool doctors can use to treat cancer,” said co-lead author Emma Milford. “This research is an important, early step towards this.”

The study is published in the journal Nature Cell Biology.

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By Chrissy Sexton, Earth.com Staff Writer