Tumors in Mice Shrunk by Targeted Immune Cells

A new treatment option has been studied at the University of Pennsylvania School of Medicine and the Nation Cancer Institute (NCI) that showed initial promise in its effectiveness on mesothelioma tumors in mice. Human studies on the therapy await further animal testing, but it could prove to be a lifesaver for the thousands of mesothelioma victims each year.
The process used altered immune cells. These were effective in shrinking the size of tumors high in the protein mesothelin. By targeting this protein, these immune cells were able to hone in on the origination site for the protein, the mesothelin genes on the surface of cancer cells. The protein acted like a homing beacon that told the immune cells exactly where the cancerous cells were located. By being able to mark the cancer cells, the healthy cells surrounding them were largely unaffected. The researchers knew from prior studies that a type of human immune cell called T-cells would seek out and attack those cells producing mesothelin protein.

It was also known that if the body creates antibodies against mesothelin protein, the tumors producing it would shrink from the antibody attack. Researchers with the University of Pennsylvania School of Medicine and the NCI combined these two pieces of prior knowledge to conduct their study. Through genetic engineering, the team created T-cells that targeted the mesothelin made on tumors. The study results showed how potent the new immunotherapy could be against cancerous tumors. Carl H. June, M.D., the head of the study and a professor of Pathology and Laboratory Medicine said of the results: “Based on the size of the tumors and the number of cells administered, we estimate that one mesothelin-targeted T cell was able to kill about 40 tumor cells.” Dr. June also notes that human studies were planned for evidence of the new therapy having an effect on mesothelioma and ovarian cancers. The specifics of the clinical trials were not released.