Because the p53 protein is activated during gene editing with the CRISPR technique, cells with this mutation have a survival advantage which can cause cancer, according to a recent study published in Cancer Research.
The CRISPR gene editing technique has significant potential in the future of precision medicine, according to a press release. However, the method has several significant hurdles before it can become widespread. One of these challenges involves cell behavior when subjected to DNA damage, which CRISPR gene editing causes. This damage activates the protein p53, which protects cells from damage.
Research had already established that the CRISPR technique is less effective with p53 is active, although a lack of p53 can also allow cells to grow uncontrollably and become cancerous. In more than half of all cancers, the gene for p53 is mutated and thus unable to protect against uncontrolled cell division. Therefore, it is essential to avoid the accumulation of such mutated cells.
In addition to these earlier findings, new research from the Karolinska Institutet has found that cells with inactivating mutations of the p53 gene gain a survival advantage when subjected to CRISPR and can therefore accumulate in a mixed cell population. The team also identified a network of linked genes with mutations that have a similar effect to p53 mutations and found that the transient inhibition of p53 is a potential pharmaceutical strategy for preventing the enrichment of cells with such mutations.
“It can seem contradictory to inhibit p53 in a CRISPR context,” said first author Long Jiang, a doctoral student at the Karolinska Institutet Department of Medicine, in the press release. “However, some of the literature supports the idea that p53 inhibition can make CRISPR more effective. In our study we show that this can also counteract the enrichment of cells with mutations in p53 and a group of associated genes.”
The study’s identification of a network of possible candidate genes to carefully control for mutations could alter the future clinical implementation of CRISPR. Another conclusion is that the transient inhibition of p53 could provide a strategy for reducing the enrichment of mutated cells, according to the press release.
The researchers have also investigated the DNA-damage response as a potential marker in the development of more precise guide RNA sequences, which show CRISPR where to alter a DNA sequence.
“We believe that the up-regulation of genes involved in the DNA damage response can be a sensitive marker for how much unspecific (‘off-target’) activity a guide RNA has, and can thus help in the selection of ‘safer’ guide RNAs,” said the study’s last author Fredrik Wermeling, a researcher at the Karolinska Institutet Department of Medicine, in the press release.
The next step for the research is to understand how relevant the described mechanisms are for the CRISPR technique and its implementation.
“In cell cultures, we see a rapid and pronounced enrichment of cells with p53 mutations when we subject the cells to CRISPR, provided, however, that cells with mutations are there from the start,” Wermeling said in the press release. “So we can show that the mechanism exists and factors that affect it, but don’t currently know at what level this is a genuine problem, and that’s something we want to explore further in more clinic-centered tests.”
New findings on the link between CRISPR gene-editing and mutated cancer cells. News release. Karolinska Institutet; November 18, 2021. Accessed November 18, 2021. https://news.ki.se/new-findings-on-the-link-between-crispr-gene-editing-and-mutated-cancer-cells