Targeted nanotherapy causes tumor eradication in mice

[Lani]

Targeted Nanoparticle Therapy Shows Promise Against Cancer in Mice



NEW YORK (Reuters Health) Apr 11 - Nanoparticles that contain docetaxel and feature a surface molecule that recognizes cancer antigens are capable of safely destroying cancer cells in vivo, the results of an animal study suggest.

In the Proceedings of the National Academy of Sciences for April 18, Dr. Robert Langer, from the Massachusetts Institute of Technology in Cambridge, and colleagues describe the creation of docetaxel-encapsulated nanoparticles with a surface aptamer that recognizes the extracellular domain of prostate-specific membrane antigen (PSMA), which is found on the surface of prostate cancer cells.

In vitro testing showed that these conjugates, which are both biocompatible and biodegradable, were able to effectively bind PSMA and then enter and destroy the prostate cancer cell. By contrast, docetaxel-encapsulated nanoparticles lacking the surface aptamer showed much less uptake and anti-cancer activity.

Testing in a murine model of prostate cancer confirmed that the aptamer-containing nanoparticles were more effective and less toxic than those lacking the aptamer. Complete tumor reduction was seen in five of seven animals treated with aptamer-containing nanoparticles compared with two of seven animals given the control nanoparticles. The corresponding survival rates were 100% and 57%.

"These bioconjugates have the advantage that the materials used in the development of the nanoparticles were approved by the US Food and Drug Administration for a prior clinical use and that the targeting molecules used in their development are small, relatively stable, nonimmunogenic, and easy to synthesize, which together may facilitate the translation of these bioconjugates into clinical practice," the authors conclude.

Proc Natl Acad Sci USA 2006;103:6315-6320.