A promising discovery in the treatment of cancer: a study shows that immune cells modified by the technique known as “genetic scissors” act durably in the body to attack tumours.
The modification by CRISPR-Cas9, the so-called “genetic scissors” technique, of immune cells brings new hope in the treatment of cancer. According to one study published in Science, T cells whose DNA has been modified by CRISPR have survived in the body and continued to attack tumors for up to 9 months after their injection. Until now, other techniques of genetic manipulation of immune cells only acted for less than a week as anti-cancer weapons.
What is this new approach? One of the ways to fight against cancerous tumors is to take T lymphocytes (white blood cells that attack abnormal cells developing in the body) from the patient and reinforce their action by genetic manipulation before reinjecting them into the patient. . Made more powerful in this way, these modified cells are weapons whose effectiveness against cancerous tumor cells has been proven.
A more lasting action than with CAR-T Cells
This technique is the one used with CAR-T Cells, T lymphocytes genetically manipulated to be able to recognize tumor antigens present only on the surface of cancer cells. By attaching themselves to their target cells, the T lymphocytes, which have become CAR-T cells, then play their role and destroy the diseased cells. The limit of the action of these CAR-T Cells is the risk, depending on the dose administered or the size of the targeted tumour, that they will act against other cells in the body and trigger an immune chain reaction that is dangerous for patients already weakened by the disease.
The method used by American scientists, which allows modified immune cells to act in a much more lasting way against cancerous tumours, is based on another technique for manipulating T lymphocytes, that which uses the CRISP-R Cas9 system. These “genetic scissors” modify the DNA of T lymphocytes in three places: the first two “cuts” of their DNA make it possible to replace the natural receptors of these cells with other more efficient ones, while the third removes a receptor from the lymphocyte T which would allow cancer cells to counter its immune action. T lymphocytes modified by CRISP-R Cas9 thus have more powerful weapons against tumor cells and an “armour” that protects them from their counter-attack. “This is the first confirmation of the ability of CRISPR-Cas9 technology to target multiple genes at the same time in humans, and it illustrates the potential of this technology to treat many diseases that could not be cured before. ”, emphasizes Carl June, lead author of the study.
Evidence of the safety of the treatment
This new arsenal against cancerous tumors has been tested in a clinical trial on three patients in their sixties with advanced cancer, two with myeloma and the third with sarcoma. First lesson: none of them suffered from side effects related to this new treatment. Then, the condition of two of the patients, if it did not improve, in any case stabilized. However, the condition of the third patient continued to deteriorate. However, the researchers remain optimistic about the evolution of the effects of this technique: according to them, their work has made it possible to ensure the safety of the treatment and its feasibility in humans, a prerequisite for other tests. effectiveness of the use of CRISPR-Cas9 on the modification of T lymphocytes in different types of more or less advanced cancers.
Below is the “Health 2030” show about the revolutionary genetic scissors:
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