Nanoparticles open door to cancer prevention

Mar 26 2009

Perhaps the best way to fight cancer is to prevent it from developing in the first place, and based on newly published research from investigators at the University of Wisconsin-Madison, nanoparticles may be able to make cancer chemoprevention a reality.

Using nanoparticles made of a biocompatible polymer, the investigators were able to encapsulate a molecule isolated from green tea that triggers apoptosis and inhibits angiogenesis, two key biochemical events that could prevent cancer. Hasan Mukhtar, Ph.D., led the team that published its results in the journal Cancer Research.

One of the chief issues in chemoprevention-the use of biologically active molecules to thwart cancer before it gains a foothold in the body-is that any such agents must be exceedingly safe, since it is likely that a person at risk for cancer would need to take the chemopreventive agent on a regular basis for a long time. Because of this requirement, many investigators have been screening naturally occuring molecules for chemopreventive activity. One such molecule, the green tea component epigallocatechin-3-gallate (EGCG), has demonstrated chemopreventive potential in a wide range of in vitro and in vivo studies. However, the body rapidly degrades this compound, limiting its clinical utility.

The Wisconsin team solved this problem using nanoparticles. When the investigators loaded biocompatible polymer nanoparticles with EGCG, they boosted its cancer-preventing activity by more than tenfold. Additional experiments confirmed that this increase resulted from a significantly longer half-life for EGCG in the body. This longer half-life correlated with a reduction in serum prostate-specific antigen levels in animals with implanted human prostate tumors.

This work, which is detailed in the paper "Introducing nanochemoprevention as a novel approach for cancer control: proof of principle with green tea polyphenol epigallocatechin-3-gallate," was supported by the National Cancer Institute. Investigators from the Albany College of Pharmacy in New York also participated in this study. An abstract of this paper is available at the journal's Web site. View abstract

http://nano.cancer.gov