A team of scientists from the U.S. has succeeded in genetically editing the immune cells of cancer patients through CRISPR. The results of the experiments were published in the journal Science, and provide hope that the technique might one day be used in patients to effectively treat cancer.
Editing cancer cells
“Researchers at the University of Pennsylvania (UPenn) removed T-cells from the patients’ blood and used CRISPR to delete genes from the cells that might interfere with the immune system’s ability to fight cancer. They then used a virus to arm the T-cells to attack a protein typically found on cancer cells called NY-ESO-1, and infused the cells back into the patients,” according to Science Alert. All three participants were aged 60 and above. They were suffering from tumors that hadn’t responded to other treatments.
CRISPR-edited T-cells were injected into the volunteers’ bodies last year and were found in their blood even nine months later. Even though the conditions of the patients stabilized during the experiment and one of them had their tumor reduced in size, the cell injections failed to work in the long-term. One patient died while cancer has worsened in the remaining two. Since the aim of the study was solely to determine whether CRISPR was safe and feasible, and not to find a cure for cancer, the study was deemed a success.
A main concern during the experiment was whether the introduction of T-cells might end up triggering an immune response since the protein being used was derived from a bacterial strain. However, nothing of this sort happened. Another worry was that CRISPR gene-editing might cause unintended cell deletions that could turn some of the cells cancerous. Though some changes in cells were observed, they were not serious enough to be considered a threat. The trial will not continue since the technique used for the study is outdated. However, the research will certainly help push forward gene editing as a tool for fighting cancer.
Edward Stadtmauer, the study’s principal investigator, “wants to create cells that can survive indefinitely in people’s bodies. The risk of edited cells turning cancerous or starting to attack healthy cells would be higher if they survive longer. But it is also possible to add a self-destruct mechanism triggered by a specific drug to kill them off if necessary,” according to New Scientist.
New editing tool
Last year, a new form of the CRISPR gene-editing tool was introduced that has the potential of expanding the range of diseases that could be treated through the technique. The updated tool, called “Prime Editing,” allows scientists to accurately change the four letters of the DNA into any other and also enables insertion or deletion of any stretch of DNA with greater efficiency.
“It has the potential to correct 89 percent of known disease-causing genetic variations in DNA, from the single-letter misspelling that causes a sickle cell to the superfluous four letters that cause Tay-Sachs disease,” according to Statnews.
There are about 75,000 diseases that are believed to be genetic. Prime Editing has the potential to deal with most of them. Prime Editing was invented by David Liu from MIT and Dr. Andrew Anzalone from Harvard. During the study, they successfully made 175 edits in human and mouse cells.