Scientists at Mount Sinai have developed a promising new strategy to fight metastatic cancer by turning the tumor’s own defense system against itself. Rather than attacking cancer cells directly, the experimental therapy targets macrophages — immune cells that surround and protect tumors.

These macrophages act as “bodyguards,” forming a barrier that shields cancer cells from attack, according to Science Daily. By eliminating that protective layer, the immune system can move in and destroy the tumor. The research, published in Cancer Cell, was led by scientists at the Icahn School of Medicine at Mount Sinai.

The novel approach was tested in aggressive models of metastatic lung and ovarian cancer — solid tumors that have proven resistant to existing treatments. Inspired by the Trojan horse strategy, researchers devised a way to dismantle the tumor’s defenses from within, allowing the immune system to do what it does best.

The team developed a therapy using CAR T cells, which are engineered from a patient’s own T cells. These modified cells are designed to selectively recognize tumor-associated macrophages while sparing healthy tissue. The researchers further enhanced the therapy by programming the CAR T cells to release interleukin-12 (IL-12), a powerful immune-regulating protein.

IL-12 plays a critical role in activating T cells and natural killer cells, both of which are essential for fighting infections and cancer. By stimulating these immune responses, interleukin-12 helps the body better recognize and attack abnormal cells, making it an important focus of cancer immunotherapy research.

When mice with metastatic lung and ovarian cancer were treated with the engineered cells, the results were striking. The treated mice lived significantly longer than untreated mice, and many were cured. Additional analyses suggested the approach could also be effective against other types of cancer.

"Macrophages are found in every type of tumor, sometimes outnumbering the cancer cells. They're there because the tumor uses them as a shield," says senior author Brian Brown, director of the Icahn Genomics Institute. "What's so exciting is that our treatment converts these cells from protecting the cancer to killing it. We've turned foe into ally."

Researchers caution that human studies are still needed to determine whether the therapy is safe and effective in people, but they say the findings mark an encouraging step forward in the fight against metastatic cancer.