Feb. 4 is World Cancer Day and we are going to give an overview of the new frontiers of cancer treatment. The journey is not over yet, but research is making progress every day.
The term “cancer” refers to a disease in which cells in the body grow uncontrollably. These form masses of cells, called tumors, which have the ability to infiltrate normal nearby organs and tissues and spread to other parts of the body through the blood or lymphatic system, altering their structure and function.
There is not just one type of cancer
The disease differs depending on the organ in which it develops, the type of cells formed, the stage at which it is found, its aggressiveness, and the possibility of metastatic development.
Despite this complexity, over the years, oncology research has evolved in the treatment and cure of various types of cancer. Small and large discoveries are made every day, and it would be impossible to report them all.
In this article we will focus on immunotherapy, T-cell transfer, and the latest applications of the Crispr technique.
Immunotherapy
Is a cancer treatment that uses a person’s immune system to fight the disease, treating it as if it was an infection.
This is done in several ways:
- By stimulating or boosting the immune system’s natural defenses so that it works harder or smarter to find and attack cancer cells
- By producing substances in the laboratory that simulate the functioning of immune system components and use them to find and attack cancer cells.
In recent decades, immunotherapy has become a major part in the treatment of some types of cancer: new therapies are being approved and new ways of working with the immune system are being discovered at a very rapid pace.
Immunotherapy, unlike chemotherapy, does not affect healthy cells but only cancer cells. It is a therapy that works better for some types of cancer than others and in some cases seems to provide better results when used in conjunction with other treatments, such as even chemotherapy itself.
There are different types of immunotherapy currently used to treat cancer. The most common are:
- Immune checkpoint inhibitors: our immune system has checkpoints that prevent it from activating immune responses that are too strong. By removing these limits, cells are able to respond more aggressively against cancer.
- Monoclonal antibodies: immune system proteins engineered in the laboratory to bind to cancer cells. Monoclonal antibodies are useful because they can be designed to attack very specific parts of a cancer cell.
- Treatment vaccines: unlike classical vaccines, which are used to prevent infectious diseases, treatment vaccines are used to fight tumors by inducing a powerful immune response.
- Immune system modulators: drugs that enhance the body’s immune response to treat certain types of cancer.
Another type of immunotherapy is T-cell transfer therapy:
T-cell transfer therapy: TIL and CAR-T
T cells are a particular type of white blood cell that possesses the natural ability to fight cancer. They are often not present in sufficient numbers to kill the tumor or to overcome the signals it releases in order to suppress the immune system.
To make up for this shortage, in transfer therapies, T-cells are cultured in the laboratory to increase their numbers and then be reintroduced into the body by injection.
There are two main types of T-cell transfer therapy:
- TIL therapy (Tumor-Infiltrating Lymphocytes): the “T-cells” found in the tumor are extracted and tested to find out which ones are better able to recognize the tumor cells. Once the correct lymphocytes are selected, they are allowed to multiply and then fed back into the system.
- CAR-T cell therapy: is similar to TIL therapy but the T-cells undergo laboratory modifications so that they are able to produce CAR protein before being cultured and injected back into the body. The CAR (Chimeric Antigen Receptor) protein is a receptor that can recognize a specific antigen present on the surface of cancer cells and bind to them. The result is cells called CAR-T that have a better ability to attack cancer cells.
Compared with other cancer therapies, CAR-Ts bring about complete remissions even in very advanced stages of the disease. The efficacy is also supported by a decrease in recurrence: one year after CAR-T infusion, most patients who have reached remission are still alive and, more importantly, no longer have the disease.
The potential of Crispr technique
T-cells modifications are executed through a virus that inserts a DNA sequence inside them, containing the information necessary for them to produce the CAR protein.
The latest evolution of this therapy, studied by a group of researchers at the University of California, involves the use of the Crispr technology. This is a laboratory method that won the Nobel Prize in Chemistry in 2020 for Jennifer Doudna and Emmanuelle Charpentier and allows to modify T-cells by acting directly on them, skipping the intermediate step of using a virus.
The results are still premature and need further study, but the exordium looks promising: out of the 16 patients with different types of solid tumors that were not responding to other therapies (CAR-Ts work well only in blood and lymph tumors), Crispr-engineered T-cells proved helpful in stopping tumor growth in 5 of them.
