Breast cancer that spreads usually infiltrates bone, causing fractures and severe pain. In such cases, chemotherapy is ineffective as the environment of the bone protects the tumor, even as the drug has toxic side effects elsewhere in the body.
Scientists at Washington University School of Medicine in St. Louis have developed a nanoparticle that can directly deliver chemotherapy to tumor cells that have spread to bone. In mice implanted with human breast cancer and exposed to circulating cancer cells likely to take up residence in bone, the Researchers demonstrated that the treatment kills tumor cells and lowers bone destruction while sparing healthy cells from side effects.
The research is available online in the Cancer Research journal.
In the study, the Researchers revealed that breast cancer cells that spread to bone carry molecules on their surface that are slightly similar to Velcro, helping tumor cells stick to the bone. These adhesion molecules also sit on the surface of cells known as osteoclasts, which are responsible for bone remodeling.
“In healthy bones, osteoclasts chew away old, worn out bone, and osteoblasts come in and build new bone,” said Weilbaecher, who treats patients at Siteman Cancer Center at Barnes-Jewish Hospital and Washington University School of Medicine. “But in cancer that spreads to bone, tumors take over osteoclasts and essentially dig holes in the bone to make more room for the tumor to grow.”