Cell Implants Reduce Tumor Growth

Cancer researchers have reduced tumor mass and slowed tumor growth in a mouse model using a novel system of microcapsules that contain cells that continually produce anticancer proteins.

Investigators at the Technion-Israel Institute of Technology (Haifa, Israel) chose human mesenchymal stem cells (MSCs) as the basis for a unique drug delivery system. MSCs are easy to obtain from bone marrow. These cells are hypoimmunogenic – they do not trigger an immune response – and can be genetically engineered to produce and secrete proteins of choice. To isolate and protect the MSCs they were sequestered inside polymeric microcapsules, which permitted the free exchange of oxygen and nutrients.

In the current study, the investigators employed MSCs that had been modified to produce hemopexin-like protein (PEX), an inhibitor of angiogenesis. Microcapsules containing the modified MSCs were injected adjacent to glioblastoma tumors in nude mice. Results published in the September 2, 2009 online edition of the FASEB journal revealed that this treatment caused a significant reduction in tumor volume (87%) and weight (83%).

Previous attempts to use encapsulated cells were not successful due to the immune reaction that they induced. Relating to the current study, senior author Dr. Marcelle Machluf, professor of biotechnology at the Technion, said, "Our method should overcome this problem. We are using MSCs, which are known to be hypoimmunogenic (that is, they reduce the body's immune reaction), and which are taken from human bone marrow. We then implant them inside an encapsulated system that protects them from the environment into which they are placed.”

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Technion-Israel Institute of Technology