Is this secret of beating cancer? Scientists can signal & # 39; Don't eat me & # 39; in disease cells – allowing the immune system to attack them
- Cancer cells give a & # 39; don't eat me & # 39; signal to evade the immune system
- Stanford researchers have discovered what it is: a protein called CD24
- By blocking CD24, they could attack the cancer in mice better
American researchers have discovered an important & # 39; not eating & # 39; signal that cancer cells seem to be using it to prevent the immune system from attacking them.
Normally, immune cells detect and swallow cancer cells, but researchers have previously discovered proteins on the surface of cells that can tell them not to.
This is useful to ward off attacks on normal, healthy cells, but scientists have discovered that cancer cells use these signals to hide.
Researchers at Stanford University School of Medicine have now discovered a new protein, called CD24, that acts as a powerful & # 39; not eating & # 39; signal capable of directly protecting cancer cells against attacks.
They believe that the discovery is a & # 39; special promise & # 39; for patients with difficult-to-treat ovarian and breast cancer, who affect thousands of women every year.
The researchers hope that most cancers can be made vulnerable to attacks when one or more signals are blocked
When the researchers blocked the CD24 signal in mice with human cancers, they discovered that it allowed the immune cells, called macrophages, to attack the cancer cells.
This led to a reduction in tumor growth and an increase in survival time in the mice.
University researchers have previously demonstrated that the proteins PD-L1, CD47 and the beta 2-microglobulin subunit of the major histocompatibility class 1 complex are all used by cancer cells to protect themselves against immune cells.
Antibodies that block CD47 are in clinical trials, while treatments targeting PD-L1 or the PD-L1 receptor are used in clinics.
A paper with a description of the research is published in Nature.
Senior author Irving Weissman, professor of pathology and developmental biology and director of the Stanford Institute for Stem Cell Biology and Regenerative Medicine, said: & The discovery that not all patients responded to anti-CD47 antibodies has fueled our research at Stanford to testing whether non-responder cells and patients may have alternative & # 39; do not eat me & # 39; signals.
Main author Amira Barkal, an MD PhD student, added: & You know that if cancers grow in the presence of macrophages, they must send a signal that prevents those cells from attacking the cancer.
& # 39; You want to find those signals so that you can disrupt them and unleash the full potential of the immune system to fight cancer. & # 39;
The team started looking for proteins that were produced more in cells with cancer than cells without, and found an abundance of CD24.
When they combined mixed cancer cells with macrophobes in a dish and blocked the signal, the immune cells began to throw themselves into cancer cells as if they were at an unlimited buffet.
Barkal added: & # 39; When we screened the macrophages after treating the cancers with CD24 blockade, we could see that some of them were simply filled with cancer cells. & # 39;
The researchers were particularly interested in discovering that ovarian cancer and triple negative breast cancer, which are difficult to treat, were strongly influenced by blocking the signaling.
They believe that CD24 is the & # 39; dominant innate immune control point & # 39; is for these cancers.
Although some cancers were prone to attack when certain signals were blocked, some were influenced by others.
They hope that most cancers can be made vulnerable to attacks when one or more signals are blocked.
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