Last month, two studies published in the journal Nature raised concerns about the potential for the gene-editing technology known as CRISPR to increase the risk of cancer, but some experts say those concerns may be overblown.
CRISPR came on to the scene about five years ago, and since then scientists have explored various ways to use the technology to edit genes to reduce the risk of disease. In broad terms, CRISPR makes use of the complex bacterial immune system and can essentially snip away a targeted piece of DNA within a cell, allowing that segment of DNA to be either knocked out through the natural process of DNA repair or replaced by a new DNA sequence. But scientists attempting to implement the technique have run into numerous challenges, both physical and moral.
Details of the studies
The two recent studies—one from Novartis and one from the Karolinska Institute in Sweden—both identified a previously unknown interaction between CRISPR and a cancer-protecting gene known as p53.
The team in Sweden had been seeking to use CRIPSR to identify genes in cancer cells that spur cancer's aggressive growth. The Novartis team had sought to develop new versions of CRISPR that would enable them to edit and study stem cells, with the hopes of one day creating cell lines that can be implanted in the body to treat neurological diseases.
What both teams found, though, was that CRISPR often was not effective in cells that contained p53 genes, which according to the Times typically protect against cancer by causing cells that might have developed mutations to either to stop reproducing or die.
When researchers disabled p53 genes, CRISPR was much more effective. That suggests, the Times reports, that scientists could simply put a temporary brake on p53 genes. However, doing so would prevent the cells from protecting their DNA from other natural mutations, potentially leading to greater cancer risk in the future.
According to STAT News, disabled p53 genes can be found in many cancer cells, accounting for nearly 50% of ovarian cancers; 43% of colorectal cancers; 38% of lung cancers; nearly 33% of liver, pancreatic, and stomach cancers; and 25% of breast cancers.
What does this mean for the future of CRISPR?
Authors of both studies said the results create some cause for concern, mainly that the technology may ultimately be less efficient than previously hoped, the New York Times reports.
Shortly after the findings were published, the Times reports stocks of several companies exploring CRIPSR treatments fell, and some in the scientific community raised concern that the findings could mean that CRISPR could be more difficult to use—and potentially more dangerous—than previously believed.
But Jussi Taipale, an author on one of the papers and a biochemist at the University of Cambridge said, "The reactions have been exaggerated," and that the findings do not necessarily suggest CRISPR is doomed. "This is not something that should stop research on CRISPR therapies," he said. "I think it's almost the other way—we should put more effort into such things."
Jacob Corn, scientific director of the Innovative Genomics Institute in California, said that these papers are "important" as they "remind everyone that genome editing isn't magic." He added that CRISPR breaks DNA in the hopes that cells will put it back together, and some cells may not be able to withstand those changes.
That being said, Corn said he doesn't believe this research is overly alarming. "We have all been looking for the possibility of cancer," he said. "I don't think that this is a warning for therapies."
Similarly, George Church, a geneticist at Harvard University said, "We should definitely be cautious," but added that the behavior of the p53 gene would likely not translate into a significant risk of cancer, though he acknowledged that "it's a valid concern" (Dearment, MedCity News, 6/12; Zimmer, New York Times, 6/12; Begley, STAT News, 6/12).
Gene-editing treatments—and 7 other technologies that could transform health care
Tomorrow’s treatments offer increasing precision and customization, ideally with less toxicity and fewer side effects. Armed with a wide array of related technologies, providers could address today’s unmet demands, such as potentially overcoming organ supply shortfalls and treating chronic conditions that are merely manageable today.
In this report, we discuss the future applications of gene editing and how CRISPR gene-editing technology could cure disorders caused by single-gene mutations.
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