Tough-Actin Actinium


Researchers at the Memorial Sloan - Kettering Cancer Center (New York) have developed a antibody conjugate that can enter cancer cells and deliver a lethal radioactive punch (Science 294, 1537-1540, 2001). David Scheinberg and colleagues attached a radioactive actinium atom to an antibody that targets specific cancer cells. After being internalized, the actinium releases a single alpha particle, a small high-energy particle that destroys the cell. In addition, as actinium decays, It creates three "daughter" atoms, each of which release an alpha particle. The tiny dose of radioactivity has few toxic side effects, and internalization of the nanogenerator prevents the daughter atoms from roaming and damaging healthy tissue. By using different antibodies, lymphoma, breast and ovarian cancer cells with extremely small doses, and with larger doses prolonged the life of mice with lymphoma and prostate tumors. The half-life of actinium is 10 days, so antibodies could be manufactured in a central pharmacy and shipped around the world. The lengthy half-life also enables penetration of larger tumors. The team hopes to begin clinical trials next year.


AIBA, (NATURE BIOTECHNOLOGY, JANUARY 2002, Vol. 20, No. 1, p. 35)