CANCER RESEARCH:
Peptide-Guided Cancer Drugs Show Promise in Mice
Marcia Barinaga
Chemotherapeutic drugs spread throughout the body, reaching not only the tumor but also healthy organs, where they kill off normal dividing cells. Tumor cells are also quick to mutate and become resistant to the drugs. Now, on page 377, a research team reveals a strategy that may get around both problems, by targeting cancer drugs to the new blood vessels that nourish the tumor. They found small peptides that zero in on the cells lining these newly formed blood vessels, then linked the peptides to the chemotherapeutic drug doxorubicin. By addressing the toxic drug specifically to the tumor, the strategy spares other tissues. And because the tumor vessel cells are not cancerous themselves, they are much less likely to develop resistance to the drugs. Indeed, when the researchers gave the peptide-drug combination to mice with large tumors, it killed off the blood vessels, stopped tumor growth, and allowed the mice to survive the cancer. What's more, the technique used to identify peptides that home in on tumor vessels can identify peptides that bind specifically to the blood vessels of other organs, meaning that peptides could be developed to carry drugs to many different tissues to treat conditions other than cancer.
