Cancer is one of the leading causes of mortality in Canada. In fact, what makes cancer an extremely hard to treat disease is the wide variety of cancer. Most cancers arise from a defect in cell division or in DNA. DNA, our genetic code, lays foundation for a wide variety of functions that our cells perform. This can include determination of our physical attributes, vulnerability to diseases and our moods to name a few. Interestingly, as the cancer develops, the number of abnormalities within the cancer cells may increase due to cancer cells making more errors as they divide. This leads to formation of a tumour in various cells, and each cell may have a unique defect associated with it. This makes specific target therapy hard to accomplish. A drug that fixes your DNA may not be able to fix defects in cell division.
Imagine playing a unique dart game with four bull’s eyes instead of one. If you want to win a game, you have to throw a dart in each of those four bull’s eyes at any given time. How would you accomplish this task? You would most likely try to throw four darts at the same time or one after the other to target each of the bull’s eyes. This is exactly the approach doctors are currently taking to treat cancer: providing combination therapies (i.e. a cocktail of different drugs to target diverse cancer cell types, either all at the same time or one right after the other). Even though this type of treatment is relatively better than previous therapies, patients receiving this treatment often become very weak due to the toxicity of the drugs.
To mitigate the side effects associated with combination therapies, modern technology is introducing exciting patient-friendly cancer therapies that will improve the outcomes of treatment. Most of these therapies involve enhancing the body’s own defense systems to kill the cancer cells. One example includes use of the body’s own immune cells, to target specific foreign agents found in our bodies. While a cancer cell is considered a foreign agent due to the abnormalities associated with it, the body’s defense system is not potent against cancer. A kind of immune cells called T-cells are the major killer cells of the body that are very specialized in nature. For example, a T-cell designed to kill one bacteria will not work against a cancer cell. This new anti-cancer therapy includes extraction of the T-cells specific to the patient’s cancer; growing them in large quantities and enhancing their killing capacity in the research laboratory; and injecting them back into the patient to improve patient’s immune response to attack cancer. This technique was recently tested in a leukemia patient, and showed positive results.
Modern biotechnology has also considerably improved targeted drug delivery for cancer treatment. Now, scientists are taking advantage of the specificity of T-cells to deliver drugs directly to the cancer cells to prevent toxic effects of drugs on the rest of the body. An example of this includes isolating the patient’s T-cells specific to the cancer cells and providing them with a “backpack.” The backpack attached to the surface of the T-cell is called a nano-pouch and is the size of 1/1000000000 of a meter! This tiny pouch contains the anti-cancer drugs which are delivered directly to the cancer cell. (Remember, one type of T-cell will only be specific to one type of foreign agent in the body so there is little risk to healthy cells). This approach looks promising, but is still being tested.
These latest biotechnology approaches are referred to as “Immune Engineering“, as the body’s immune system is engineered within the laboratory to enhance its function in getting rid of pathogens and abnormal cells. This technology is even more exciting because of its applicability to other diseases as well. Scientists are working hard to use immune engineering to better treat diseases such as HIV, autoimmune arthritis and multiple sclerosis. I am very excited to learn more about how modern technology can help us solve complex medical challenges and I hope you are too!