CRISPR makes enhanced cancer-fighting immune cells inside mice

Once delivered to cells, the CRISPR-Cas9 gene-editing system (purple and pink) cuts DNA in specific places.Credit: Ruslanas Baranauskas/Science Photo Library

The powerful gene-editing technique CRISPR–Cas9 might offer a way to make safer, more effective cancer-fighting immune cells engineered inside the human body, a mouse study has found.

Cancer-fighting immune cells could soon be engineered inside our bodies

The research, reported on 18 March in Nature1, adds new safety features to an emerging class of cancer treatments known as chimeric antigen receptor (CAR)-T-cell therapies that are produced in the body. The development could lead to treatments that are cheaper to make and easier to administer than are those currently used against some blood cancers.

At present, CAR-T therapies are made from a person’s own T cells — a type of immune cell — which are isolated, engineered to express a synthetic protein known as a CAR and then reinjected into the body. Reprogramming T cells directly in the body would take less time, but it adds safety concerns, says Justin Eyquem, an immunologist at the University of California, San Francisco, and lead author of the study. For one thing, “you don’t want to edit other cells”, he says. “So we added multiple layers of safety.”

Find and destroy

CARs are designed to target cancer cells, allowing the engineered T cells to find and destroy tumours — an approach that has produced dramatic remissions in some people with cancers of the blood, such as leukaemia or lymphoma.

Not only are current CAR-T-cell therapies costly and time-consuming, but recipients must also endure toxic pretreatments, often with chemotherapy drugs. These obliterate the recipients’ unaltered immune cells so that the CAR T cells have room to flourish. But they leave people temporarily vulnerable to infection.

As a result, researchers have been trying to instead engineer T cells in vivo, or in the body. With that approach, companies could produce a single therapy that would work for many people, and recipients would not need chemotherapy pretreatment.

Far fetched?

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