Their novel treatment, presented at the annual meeting of the American Society of Hematology (ASH), may offer the first gene therapy "delivery system" capable of homing in on and then attacking cancer that has metastasized -- wherever it is in a patient's body. And the stem cells will not be rejected, even if they are not derived from the patient.
The researchers have tested the system in mice with a variety of human cancers, including solid ones such as ovarian, brain, breast cancer, melanoma and even such blood-based cancer as leukemia. "This drug delivery system is attracted to cancer cells no matter what form they are in or where they are," says Michael Andreeff, M.D., Ph.D., professor in the Departments of Blood and Marrow Transplantation and Leukemia. "We believe this to be a major find."
M. D. Anderson has filed patent applications on the system, which uses human mesenchymal progenitor cells (MSC), the body's natural tissue regenerators. These unspecialized cells can migrate to an injury by responding to signals from the area. There they develop the kind of connective tissue that is needed to repair the wound, and can become any kind of tissue required.
Tumors are "never-healing wounds" which use mesenchymal stem cells to help build up the normal tissue that is needed to support the cancer, says Andreeff. "There is constant remodeling of tissue in tumors," he says. So researchers turned the tables on the cancer, taking advantage of a tumor's ability to attract the stem cells.
In their novel delivery system, researchers isolate a small quantity of MSC from bone marrow, and greatly expand the quantity of those cells in the lab. They the
Contact: Julie Penne
University of Texas M. D. Anderson Cancer Center