New encapsulated system may enable doctors to deliver anti-cancer drugs directly to tumors

Nov 18 2009

An encapsulation breakthrough by researchers at the Technion-Israel Institute of Technology may enable doctors to deliver anti-cancer drugs directly to tumors over extended periods of time, while preventing the systemic side effects of chemotherapy and other current cancer treatments.

The system consists of polymeric microcapsules containing human mesenchymal stem cells (MSCs) engineered to produce proteins that prevent cancer growth. The system is novel because it isolates and protects the encapsulated MSCs from their surroundings while allowing for the free exchange of nutrients and oxygen they need to survive.

In the journal FASEB, the researchers report that this system led to an 87% reduction in volume and an 83% reduction in weight of a treated glioma tumor in mice after two weeks of treatment.

According to lead researcher Prof. Marcelle Machluf of the Faculty of Biotechnology and Food Engineering, previous attempts to encapsulate cells that create anti-cancer drugs and implant them near cancerous tumors were unsuccessful mainly because the cells eventually triggered immune reactions in the body.

"Our method should overcome this problem," says Prof. Machluf. "We are using MSCs, which are known to be hypo-immunogenic (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."

In addition to their hypo-immunogenic properties, MSCs (which can also easily be isolated from fat tissues, cord blood, and placenta) are known for having long-lasting viability. Because they can proliferate for long periods of time inside the microcapsules, the researchers engineered them to produce drugs (in this case, proteins that prevent cancerous growth). The microcapsules can be implanted adjacent to the tumor, and the cells they contain create anti-cancer proteins, which are released through the capsule membrane walls to the tumor site over a pre-determined timed period.

The researchers are now planning to test the system in larger animals. The Technion has already registered a patent on this development.