Natural killer cells remember and effectively target ovarian cancer, researchers discover

Researchers at Karolinska Institutet have uncovered a unique ability of a special subtype of natural killer cells in the immune system, called adaptive NK cells, to remember ovarian tumors and effectively attack them. The discovery, published in Cancer Immunology Research, could pave the way for new, more powerful immunotherapies for difficult-to-treat cancers. The paper is titled “Adaptive NK Cells Exhibit Tumour-Specific Immune Memory and Cytotoxicity in Ovarian Cancer.”

NK cells, or natural killer cells, are white blood cells that play a central role in the body’s defense against viral infections and cancer. NK cells can identify and destroy unhealthy-looking cells, such as tumor cells, without prior exposure.

Adaptive NK cells, aNK cells, are a subset of NK cells that can remember past infections or tumors and react more strongly the next time they encounter the same threat. This ability makes them particularly promising for cancer treatment.

The study shows that aNK cells can remember tumor-specific signals, infiltrate and fight cancer cells, and cooperate with other immune cells to become even more effective, making them particularly attractive for cancer treatment.

“Our results demonstrate that aNK cells have great potential for treating cancer, especially for patients with difficult-to-treat ovarian cancer,” says Dhifaf Sarhan, senior lecturer at the Department of Laboratory Medicine, Karolinska Institutet, who led the research.

“The study also challenges previous perceptions of NK cells, which have historically been considered only innate immune cells with no memory function against cancer,” she continues. “This opens new opportunities for the development of innovative immunotherapies.”

The study involved comprehensive analyses of human immune cells and ovarian tumor tissues, utilizing advanced RNA and gene expression mapping techniques at the single-cell level. This allowed the researchers to investigate how aNK cells interact with ovarian cancer tumor cells.

“The next step in our research is to develop methods that increase the number and activity of aNK cells in patients, followed by clinical trials to evaluate their effect on patient survival rates,” says Sarhan.