The past few years have seen a rising interest in the development of genome editing, or "gene editing."
Gene editing is the use of highly sensitive and precise technologies that let specialists alter segments of human DNA for therapeutic purposes.
More specifically, scientists are interested in intervening in the genetic variants that may raise someone's risk of developing certain diseases, including cancer.
But while gene editing — and specifically a precision editing tool called CRISPR-Cas9 — has been said to show promise, new research warns that we would do well not to jump to any conclusions just yet.
Two independent research articles now published in the journal Medicine Now both report that gene editing tools may, in fact, inadvertently boost the risk of cancer by disrupting a very fine cellular mechanism.
One study — conducted by Dr. Emma Haapaniemi and colleagues from the Karolinska Institutet in Stockholm, Sweden, and the University of Helsinki in Finland — has now discovered that using CRISPR-Cas9 to edit DNA in human cells may have undesirable consequences.
How CRISPR could increase cancer risk
In testing CRISPR-Cas9 on human cells in vitro, Dr. Haapaniemi and her team noted that the editing process is liable to activate the protein p53, which binds DNA.
Therefore, in cells where p53 is present and becomes active, it will react to "repair" the DNA where CRISPR-Cas9 has "cut in."
This counteraction can slow down or inhibit the efficacy of the genome editing tool, meaning that CRISPR-Cas9 works best in cells that lack p53, or which cannot activate this protein.
But there's a catch: p53 is also a tumor suppressant, so in cells where p53 is lacking or not in working order, this may lead to the cells multiplying abnormally and therefore becoming malignant.
"By picking cells that have successfully repaired the damaged gene we intended to fix, we might inadvertently also pick cells without functional p53," explains Dr. Haapaniemi.
And, "If transplanted into a patient, as in gene therapy for inherited diseases," she cautions, "such cells could give rise to cancer, raising concerns for the safety of CRISPR-based gene therapies."
Side effects of gene editing to be considered
Because of these worries and risks, the scientists involved in the recent study warmly advise that researchers looking into the therapeutic potential of genome editing tools should also seriously consider what side effects might arise, and how best to deal with them.
"CRISPR-Cas9 is a powerful tool with staggering therapeutic potential," admits study co-author Dr. Bernhard Schmierer.
However, he adds that it should be treated with much caution, encouraging that further work be conducted to fully understand the implications of CRISPR-Cas9 and p53 interactions at cellular level.
"Like all medical treatments," he says, "CRISPR-Cas9-based therapies might have side effects, which the patients and caregivers should be aware of."
"Our study suggests that future work on the mechanisms that trigger p53 in response to CRISPR-Cas9 will be critical in improving the safety of CRISPR-Cas9-based therapies."
Dr. Bernhard Schmierer