CAR-Engineered NK Cells Show Promise Against Breast Cancer

While CAR-T cells have been successfully used against hematologic malignancies, their use against solid tumors has been plagued by off-tumor effects. Now researchers at McMaster University have developed modified natural killer cells they say can differentiate between cancer cells and healthy cells, destroying only the targeted cells.

The team set out to develop a treatment with the same power as CAR-T, but which could be used safely against solid-tumor cancers. They first propagated natural killer cells taken from the blood of patients with breast cancer. They then genetically modified them to target specific receptors on cancer cells, successfully testing the CAR-NK cells in the laboratory on tumor cells derived from breast cancer patients

"We want to be able to attack these malignancies that have been so resistant to other treatments," says Ana Portillo, lead author of a paper published in iScience. "The efficacy we see with CAR-NK cells in the laboratory is very promising and seeing that this technology is feasible is very important. Now, we have much better and safer options for solid tumors."

"These CAR-NK cells are a little bit smarter, in a way, in that they only kill the enemy cells and not good cells that happen to have the same marker," says Ali Ashkar, senior author. "These cells have a sober second thought that says, 'I recognize this target, but is this target part of a healthy cell or a cancer cell?' They are able to leave the healthy cells alone and kill the cancer cells."