Stem cells, immature cells already showing promise as tools to regenerate and replace damaged tissue, may also help target and destroy cancer, U.S. scientists said on Monday.
Tests in mice showed the cells could deliver powerful cancer-killing proteins, destroying tumors while leaving healthy cells untouched.
Dr. Michael Andreeff and colleagues at the University of Texas M. D. Anderson Cancer Center in Houston used cells taken from bone marrow. These immature cells, known as mesenchymal stem cells, usually give rise to muscle and other tissues.
The researchers genetically engineered these cells to carry interferon alpha, an immune system protein that can help kill cancer cells, or a cancer-destroying virus.
Cells attracted to cancers
In mice these cells slowed several kinds of leukemia, attacked melanoma -- skin cancer and breast cancer cells --that had spread to the lung, and tackled brain tumors.
The approach cured 70 percent of mice implanted with one kind of human ovarian cancer, the researchers told a meeting of the American Association of Cancer Research in Orlando, Florida.
“This drug delivery system is attracted to cancers, both primary and metastatic, and anti-tumor effects are observed when the cells integrate into the tumor micro-environment,” Andreeff said in a statement.
“The most important discovery here is that these cells are capable of migrating from the bone marrow or blood circulation selectively into tumors and produce anti-tumor agents only at the sites of these tumors and their metastasis.”
Andreeff said tumors attract mesenchymal stem cells by sending out signals similar to those sent by damaged tissue.
