Scientists reprogram key immune cells to attack deadly brain cancer

Scientists have published a new study detailing the use of tumor-promoting immune cells to attack an aggressive, often fatal form of brain cancer. The work involves 'reprogramming' these cells so that they switch from protecting cancerous brain tumors to attacking them. The researchers note that some of the mice involved in the study not only rejected the brain tumors but also developed a long-term immunity against them.

The study, which comes from Massachusetts General Hospital and other research institutions in Boston, focused specifically on glioblastomas, a type of aggressive and deadly cancer notably resistant to treatment. The researchers note that a class of drugs called immune checkpoint blockers (ICBs) aren't an effective way to treat this type of cancer.

The reason is that despite ICBs triggering inactive immune cells to attack cancer cells while leaving healthy tissue mostly untouched, glioblastomas evade this treatment by creating their tumor microenvironment, one that takes over immune cells, proteins, and blood vessels and uses them to promote the tumor's growth.

This results in a blocking of the immune cells that would attack the tumor while allowing in regulatory T-cells (Tregs), which are immune cells that promote the tumor's growth. The scientists found that they could target these accumulated Tregs in the cancerous tumor and 'reprogram' them to attack the cancer cells they originally protected.

"Because Tregs already present in these tumors can be reprogrammed, this strategy does not rely on additional recruitment of anti-tumor immune cells – another frequent barrier to successful immunotherapy in brain tumors," explained Rakesh K. Jain, Ph.D., one of the researchers behind the new study.

The research involved mice with human glioblastomas, paving the way for potential future ways to treat this deadly form of brain cancer in humans.