Pre-made stem cells may be pulled off the shelf to treat aggressive cancer

The idea of using stem cells engineered to target tumor cells is starting to gain traction as a way of tackling difficult-to-treat cancers, and highly aggressive brain cancers known as glioblastomas (GBMs) are a prime candidate.

The trouble is that glioblastoma and other aggressive cancers can advance very rapidly, offering a very short window for these very complicated types of therapies to be carried out. A more effective approach might be to have a bank of cells sourced from healthy donors that are engineered to tackle different cancers, and are ready to be deployed soon after a patient's diagnosis. This is the vision being pursued by the authors of the new study, from Brigham and Women’s Hospital and Harvard Medical School.

First, the scientists identified special receptors on cancer cells circulating through the bloodstream they call "death receptors." They then took stem cells from healthy donors and engineered them to release proteins that bind to these receptors to trigger the death of the cancer cells. They also incorporated a safety switch function into the stem cells that causes them to self-destruct once their work is done, while further driving cancer cell death.

These cells were packaged into biodegradable hydrogel capsules and administered to mice with glioblastoma after surgical removal, with all that received the treatment still alive 90 days later.

A control group of mice that underwent surgery but didn't receive the stem cell treatment had a mean survival time of 55 days. The scientists also treated the mice with varying doses of the stem cells to ascertain the safety of the therapy, and detected no signs of toxicity.