The immune system is an incredible evolutionary machine, designed to protect us from the ravages of bacteria, viruses, and other harmful microbes. But admittedly, there are some times when the immune system doesn’t work the way it is supposed to, giving rise to auto-immune disorders. And now scientists have demonstrated how a hijack of the immune system from melanoma cells can cause the cancer to spread.
In a study funded by The Cancer Research UK, researchers looked cells from both mice and human melanoma tumors. Cells on the edges of these tumors have a high level of a protein called Myosin II. This protein is found in a bunch of different cell types. It is what is called a motility protein, which basically means it allows cells than contain this protein to move within the body. Every time you flex a muscle (even if it’s just to smile or frown), you have Myosin II to thank. The next time a meathead at the gym flexes near you, tell him it’s an impressive display of his Myosin II proteins.
Anyway, while great for our muscles, we really don’t want mobile melanoma cells in our bodies. And the researchers discovered that high levels of this protein (like the ones found in these melanoma cells) release chemicals that actually reprogram the functioning of the immune system in ways that can be very harmful. One of the chemicals is interleukin 1A, which was discovered to be key for making cancer cells more invasive
So these melanoma cells release a high level of a protein (Myosin II) and that protein releases chemicals, with me so far? The chemicals affect nearby immune cells (called macrophages) which normally would possess the ability to fight and sometimes kill the cancer cells. But because of the presence of these chemical, the macrophages instead help the cancer cells survive and become more invasive.
Even worse, the chemicals released by high levels of Myosin II make tiny holes in blood vessels. This allows the melanoma cells to escape into the bloodstream and travel to sites in the body away from the original tumor site.
So why is this line of research good news? As the study’s lead author Professor Vicky Sanz-Moreno said: “This study highlights how cancer cells interact with and influence their surrounding environment to grow and spread. Developing treatments that target the chemicals that alter the immune system could help to prevent the spread of the disease.”
There are already drugs on the market that block Myosin II activity, including an existing treatment for glaucoma. And interleukin 1A inhibitors are currently being tested in clinical trials for colon cancer. Scientists can direct future research towards discovering whether these or other Myosin II and interleukin 1A inhibitors could be used in the fight against melanoma.
While this research will lead to more investigation, the outcome of the study shows that while melanoma and other cancer cells exhibit ingeniously scary ways to evade our immune system, we are discovering those tricks with an eye towards developing potential treatments. It may not lead to a cure; but it should help create more effective options for melanoma sufferers.