The compounds, called synthetic migrastatin analogues, prevented 91 to 99 percent of metastatic breast cancer cells in mice, and are the first to target only metastatic cells.
"They're unbelievably effective, and in vitro study suggests they'll work just as well at inhibiting the migration of prostate and colon cancer cells," said senior researcher Dr. Xin-Yun Huang, Professor of Physiology and Biophysics at Weill Cornell Medical College in New York City.
The findings have just been published in Proceedings of the National Academy of Sciences.
For decades, doctors have fought cancer by using surgery, chemotherapy, or radiation to excise or shrink the primary tumor.
"However, in too many cases it's simply impossible to completely remove the tumor," Dr. Huang explained. "So recently the idea of targeting cell migration -- metastasis -- has become an alternative strategy that's gained a lot of interest among researchers."
If compounds could be found that slowed or halted cancer spread, doctors could gain valuable time in shrinking the primary tumor. "If we had the luxury of time, we could treat that primary tumor at lower doses, too, with fewer side effects for the patient," Dr. Huang said.
Until now, agents that specifically target metastatic cells have remained elusive. However, a new avenue of research opened up when Dr. Huang's team noticed that the Streptomyces bacterium -- the bug that gives us the antibiotic streptomycin -- also produces a natural compound called migrastatin, which appears to inhibit cell migration.
Natural migrastatin's effect is relatively weak, but Dr. Huang suspected the molecule might be manipulated in