Researchers from The University of Texas M. D. Anderson Cancer Center have potentially found a way to use stem cells to deliver a gene therapy that fights pediatric bone tumors. The preclinical study in mice could lead to a therapy that avoids systemic toxicity from chemotherapy by directly targeting the tumor.
The study tested mesenchymal stem cells (MSCs) from mouse bone marrow to see if they could deliver the gene therapy, interleukin-12 (IL-12), directly to Ewing's sarcoma tumors. The stem cells were infused with the IL-12 gene and then administered intravenously into the mouse. A series of experiments confirmed that the stem cells delivered IL-12 to the tumor and that the gene therapy significantly inhibited tumor growth.
Eugenie Kleinerman, M.D. (pictured), division head for the Children's Cancer Hospital at M. D. Anderson, has done extensive research on pediatric bone tumors such as Ewing's sarcoma and osteosarcoma. Kleinerman's previous research has shown the ability of IL-12 to inhibit tumor growth in Ewing's sarcoma and osteosarcoma. IL-12 is a gene that prevents tumors from forming new blood vessels that allow them to grow.
In August, Kleinerman had research findings published in the International Journal of Cancer, which reported that bone marrow cells migrated to Ewing's sarcoma tumors and helped form the new blood vessels that support tumor growth.
"We already knew that IL-12 had a significant impact on tumor growth of bone cancers," Kleinerman says. "When we discovered that some bone marrow cells are attracted to tumors, we looked into finding the specific stem cells that could function to deliver the gene therapy to the tumor and hopefully avoid systemic toxicity."
Currently, patients with Ewing's sarcoma receive multi-agent chemotherapy with surgery and/or radiation. According to a study by Douglas Hawkins, M.D., from the University of Washington School of Medicine, the 2-year disease-free survival rate for patients with localized disease receiving this aggressive treatment has remained at 60 to 70 percent. For patients whose Ewing's sarcoma has metastasized, their 2-year disease-free survival rate drops to 10 to 30 percent. The cure rate for patients who are diagnosed with metastasis is less than 10 percent.
"There is a great need for new therapeutic approaches for treating Ewing's sarcoma patients, especially those who have relapsed or who have metastases," Kleinerman says. "Plus, the long-term effects and secondary cancers associated with intensive chemotherapy and radiation validate the need for more effective and less toxic therapies for young patients."
Illustration: University of Texas M. D. Anderson Cancer Center.
University of Texas M. D. Anderson Cancer Center News Release (12/08/08)
Abstract (Cancer; Vol. 115, Issue 1, 13-22 (12/02/08))