Can our own immune system beat cancer?
9 November 2015
The MRC’s annual science writing competition, the Max Perutz Science Writing Prize, challenges MRC-funded PhD students to communicate the importance of their research to a non-scientifically trained audience in 800 words or less. This year, several students from the WIMM submitted excellent entries to the competition, including Tomek Dobrzycki (whose entry was published on the blog last month) and the article below written by Lauren Howson, a DPhil student in Enzo Cerundolo’s lab.
Our immune system is killing cancer cells all the time.
Although the better known function of the immune system is to survey and protect the body from invading bugs and viruses, it is also equipped to detect cells that may be on their way to becoming cancer cells. Our immune cells can detect these cells, as they have altered molecules on their surface. They are then able to tell that cell to die without harming surrounding cells.
Cancer cells arise because our cells are continually dividing and giving rise to new cells. The lining of the stomach is replaced every few days, and skin is constantly shedding its outer layers and giving rise to new cells. So with all this dividing of DNA there is a high probability of something going wrong. The cells can sometimes get the wrong set of instructions on how they should grow. They can begin to grow out of control and this is what eventually leads to cancer.
With this enormous number of dividing cells you would think mistakes in programming would happen much more often. The truth is it happens all the time, but our body has a system in place to detect and kill any cell that shows signs of becoming cancerous, and this system is our immune system.
The immune system is a highly complex system made up of many different cells that communicate with each other to coordinate immune responses. Each type of cell has a different job. They can be detectors, messengers, responders, killers, cleaners or control the response to make sure it doesn’t get carried away and end up damaging healthy cells.
So with such a sophisticated system in place, why do we get cancer? This happens when one or more of these immune cell types fail to see the cells that are becoming cancerous. Essentially, the cancer cells have outsmarted the immune system by either hiding their identity or by communicating to immune cells to suppress their anti-cancer activity.
Current treatments for cancer such as chemotherapy are killing cancer cells but it also damages the healthy cells in the process, because it is not specific. This is why those undergoing chemotherapy end up becoming sicker during treatment. In contrast, our immune system is already trained at selecting cells based on certain surface molecules and specifically telling those cells to die without harming the surrounding tissue.
With these naturally occurring cancer fighting cells in our body the question needs to be asked: is there a way we can train them to outsmart the cancer cells and to make a safer and more specific treatment for cancer? This is exactly what I am asking as part of my research project. I am focussing on figuring out whether certain immune cells have the ability to recognise cancers and if they could be activated in order to help fight cancer.
Research into this possibility has been going on for some time, with scientists testing different cancer immune therapies where they either remove a cancer patients cells or target them inside the body, and try to train them to recognise and reject the cancer. However, this has had limited success. This is because the immune system is so complex with many different cells contributing to the outcome of a response. This is why research into better understanding the details of our immune system is so important.
Researchers are identifying new types of immune cells all the time. My research is focusing on a newly identified cell within the immune system that may be important for anti-cancer immunity. These cells are part of the responder immune cell family of T cells, but fit into a special category called “innate-like” T cells. They have already been studied in great detail in different kinds of bacterial infections.
These innate-like T cells are especially interesting as they are able to be stimulated by a specific set of small molecules that are found in bacteria but not in our own body. These molecules act as warning beacons as they are taken up by immune cell detectors that can then show these molecules to these innate-like T cells that then shift the balance of the immune response. They do so by quickly changing the communications between many immune cells and can turn the previously outsmarted immune cells into active smart ones. These innate-like T cells also have the ability to directly kill cells, which is a property essential for anti-cancer immunity.
We have found these innate-like T cells are present in cancer tissue but don’t know what their role is and how they are influencing the body’s response. The answer to potentially harnessing these cells unique therapeutic properties and shifting the balance into beating cancer lies in finding this out.