US researchers have discovered a major’ don’t consume me ‘ signal that cancer cells seem to use to prevent the immune system from attacking them. Immune cells normally detect and swallow cancer cells, but researchers have previously discovered proteins on the cell surface that can tell them not to do so. This is useful in preventing attacks on normal, healthy cells, but scientists have found that these signals are being used to hide cancer cells.
Researchers at Stanford University School of Medicine have now discovered a new protein called CD24, which acts as a powerful ‘don’t eat me’ signal’ capable of defending cancer cells straight from attack. ‘They think that the discovery holds’ special promise’ for those suffering from hard-to-treat ovarian and breast cancer that affects thousands of females every year.
They discovered that this permitted the immune cells, called macrophages, to attack the cancer cells when the scientists blocked the CD24 signal in mice implanted with human cancers. This has resulted in decreased tumor development and increased mice survival time. University researchers have earlier shown that cancer cells are all used to safeguard themselves from immune cells by the enzymes PD-L1, CD47 and the beta-2-microglobulin subunit of the significant histocompatibility class 1 complex. Clinical studies contain antibodies that block CD47, while hospitals use medicines that target PD-L1 or PD-L1 receptors.
When in a meal they combined blended cancer cells with macrophobes and blocked the signal, the immune cells began’ gorging on cancer cells as they were at an all-you-can-eat buffet.’ Barkal added:’ When we pictured the macrophages after treating the cancers with a blockade of CD24, we could see that some of them were just stuffed with cancer cells.’
Researchers were particularly interested in finding that ovarian and triple negative breast cancer, which is difficult to treat, were highly affected by blocking the signals. They think that for these cancers, CD24 is the’ dominant innate immune checkpoint.’ While some cancers were susceptible to attack when certain signals were blocked, some were affected by others. They hope that most cancers will be able to be made vulnerable to attack when one or more of the signals are blocked.