life support tumor bone marrow cells, in blue, have migrated to the tumor site (above). a special staining technique determines what type of cells in the bone marrow, they are (bottom).
Like the rest of the body, tumors need blood to survive, and a hot area of research is to find ways to block this food. Now, cancer researchers have discovered a new way to approach this. By stopping the tumors recruit raw materials to build their network of blood vessels, a process called angiogenesis, they can prevent tumor growth
Researchers used to think that recruited tumors new cells of blood vessels from existing vessels in the vicinity. Then, in 1999, a team found that when a set of known genes Id1-4 is disabled in mice, the animals can not develop tumor blood vessels. Normally, the Id genes are active in embryonic development of blood vessels, then turned off permanently after birth.
cancer biologists David Lyden, Shahin Rafii and Robert Benezra and a joint team from Memorial Sloan Kettering Cancer Center, Cornell University Medical College, and ImClone Systems Inc., all in New York, wanted to know if Id genes allow tumors to recruit building blocks from the bone marrow, which helps build blood vessels. Using mice that lacked Id genes and can not build new blood vessels in the tumor, the team replaced Lyden mouse bone marrow with normal Id containing bone marrow. Then they implanted tumors under the skin of the animal. Within hours, the cells in the bone marrow have migrated to the tumor.
Although previous estimates have suggested that cells from bone marrow accounted for 5% to 10% of new blood vessels, Lyden said, the new data suggest "bone marrow is really responsible for the network of blood vessels of the entire tumor. "researchers have also developed antibodies to a receptor on the surface of cells in the bone marrow which receives the enticing signal tumors. These antibodies prevented signals to the blocked marrow and halted the growth of blood vessels of the tumor.
"seminal" is how tumor angiogenesis researcher Judah Folkman of Harvard Medical School in Boston described the work. "the concept that there is a regular traffic of endothelial precursor cells bone marrow in the bed of the tumor is a novel very, important discovery, "he said. the results, he said, could open the door to a new class of anti-angiogenic drugs that can help to combat growth of the tumor.
Related Sites
Summary Lyden et al . Nature Medicine paper
Rafii laboratory homepage
Benezra laboratory homepage
Lyden et al s'. 1999 Nature paper first link Id proteins to tumor angiogenesis
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