Cancer-Killing Stem Cells

Researchers at Harvard Medical School have engineered cancer-killing stem cells in laboratory mice. These scientists, working specifically at the Harvard Stem Cell Institute at Massachusetts General Hospital, released the results of this pioneering study in the February 2015 issue of Stem Cells.  Through experiments on mice, stem cells were genetically altered to produce and secrete toxins that specifically target brain tumors while causing no harm to themselves or normal brain cells in the process.

Genetic engineering allowed these researchers to develop a strain of stem cells that are resistant to the toxins they produce, while also secreting specific cytotoxins that kill glioblastoma tumors in the brain.  The toxins are specifically a Pseudomonas exotoxin, which has previously been used as an antitumor agent.  However, there had always been problems in the past with using this toxin clinically on patients; some of the issues encountered include difficulty reaching the tumor itself/off-target delivery, a short lifespan, and systemic toxicity.  By altering the stem cells to overcome these issues, it has allowed for a novel approach to using this type of technology in a meaningful way.  In the tests themselves, the stem cells were placed in a biodegradable synthetic gel and then placed at the site of the tumor, after it had been excised from the mouse brain.  The cancer cells were then exposed to the toxins and died, while leaving the stem cells and normal tissue unharmed.

The next step in this research will be to test other therapies on the glioblastoma cancer cells in mice using the same delivery method.  Then, eventually this technique will have to be tested on humans.  Glioblastoma is the most common brain tumor in human adults, so this research is very relevant to survival of these patients.

This type of research also opens the door to using similar techniques to treat a wide array of solid tumors.  Once again, this highlights the amazing abilities of stem cells in the future of modern medicine.