Using a mouse model of myeloma, a type of bone cancer, scientists at HMS tested a nanoparticle drug-delivery system they engineered from clinically safe biodegradable polymers and alendronate, a bisphosphonate-based therapeutic agent for cancer, and found the targeted therapy to be effective, capable not only of killing tumor cells but also of stimulating growth of healthy bone tissue.
The research, the result of a collaboration between investigators at Brigham and Women’s Hospital and Dana-Farber Cancer Institute, was reported in the June 30 issue of the Proceedings of the National Academy of Sciences.
For the study, the research team injected mice with nanoparticles loaded with bortezomib, an anticancer drug. Then they introduced myeloma cells into the animals. The scientists found that the nanoparticles, aided by the alendronate, homed in on the bone tissue and delivered their drug cargoes, killing the tumor cells.
Alendronate played a dual role in this engineered system. Bisphosphonates bind to calcium, and since the largest store of calcium in the human body is in bone, the bisphosphonates accumulate in high concentration in bones. In addition, bisphosphonates are commonly used in the treatment of cancers that metastasize to the bone.
The research team found that the treatment slowed myeloma growth and prolonged survival. Moreover, they found that bortezomib changed the makeup of bone, enhancing its strength and volume.
“These findings suggest that bone-targeted nanoparticle anticancer therapies can deliver a concentrated amount of drug in a controlled and target-specific manner capable of preventing tumor progression in multiple myeloma,” says Omid Farokhzad, an HMS associate professor of anaesthesia and director of the Laboratory of Nanomedicine and Biomaterials at Brigham and Women’s, and the study’s co-senior author. “This approach may prove useful in treating bone metastasis, common in 60 to 80 percent of cancer patients, and in treating early stages of multiple myeloma.”
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