Cancer cells use the "do not eat me" signal to prevent the immune system from attacking them, a study finds

According to new research, cancer cells send a "do not eat me" signal to prevent the immune system from attacking them.

Normally, they are engulfed by immune cells, but scientists have previously discovered that proteins on the surface of certain cancer cells forbid them to do so.

This prevents healthy cells from being attacked, but researchers at the Medical School of Stanford University, California, have discovered that cancer cells use the same signals to hide themselves.

They discovered that the new "do not eat me" signal comes from a protein called CD24. This could help heal the victims of difficult-to-treat ovarian and bad cancers, which affect thousands of women every year in the UK.

When researchers blocked the CD24 signal in mice with human cancer, they discovered that it allowed immune cells, called macrophages, to attack cancer cells.

This led to a reduction in tumor growth and an increase in the survival time of the mice, they wrote in their conclusions that were published in the newspaper Nature.

Researchers at the same university have already shown that cancer cells use other proteins to protect themselves from immune cells. Antibodies that block a protein called CD47 are currently undergoing clinical trials.

"By treating cancers with antibodies that block CD24, we can remove this" armor shield "and allow macrophages to effectively eliminate cancer," said Amira Barkal, PhD student and lead author of the latest study.

"More research is needed to determine which patients will benefit most from CD24 blocking therapies. Ovarian cancer and bad cancer are two of the most deadly diseases that affect women. These are very aggressive cancers that are notoriously difficult to treat in the clinic. We are excited about the potential of these findings to provide a new strategy for treating and perhaps even curing ovarian cancer and bad cancer. "

His fellow author Irving Weissman, professor of pathology and developmental biology and director of the Stanford Institute of Stem Cell and Regenerative Medicine, said: if non-responder cells and patients can receive alternative signals "Do not eat me". "

The team started looking for proteins that were more highly produced in cancer cells than those that were not, and found an abundance of CD24.

When they combined cancer cells mixed with macrophobes in a box and blocked the signal, the immune cells began to "gorge themselves on cancer cells as if they were at an all-you-can-eat buffet."

Ms. Barkal added, "When we took images of macrophages after treating CD24-blocking cancers, we found that some of them were simply packed with cancer cells."

The researchers were particularly interested in finding that ovarian bad cancer and triple-negative, difficult to treat, were strongly affected by the blockage of signaling. They believe that CD24 is the "innate immune control point" for these cancers.

Rebecca Rennison, Director of Public Affairs and Target Ovarian Cancer Services, said, "It is essential to find more effective treatments for ovarian cancer in order to combat this devastating disease. We have found fantastic results in immunotherapy in other cancers, but its effectiveness in ovarian cancer has not yet been proven.

"Today's announcement is very promising in this area and, if corroborated by new research, it would be a major step forward."

Additional reports by PA