Nanotech News

October 24, 2005

Therapeutic Nanoreactors Deliver Cell-Killing Chemical Reactions

One way to protect healthy cells from the effects of chemotherapy agents is to create a form of the drug, known as a prodrug, that is essentially inert until it enters a cancer cell and is transformed into an active drug by some enzyme present in malignant but not healthy cells. Finding such enzymes has proven difficult, however, so a research team in Switzerland has developed a nanoscale reactor, or nanoreactors, that has the potential to activate prodrugs within cancer cells.

Patrick Van Gelder, Ph.D., and his colleagues at the Vrije University Brussel, in Belgium, created the spherical nanoreactors using a three-part polymer and pore-forming proteins found in bacteria. These pore-forming proteins create channels that allow prodrug molecules to pass through the wall of the nanoreactors and reach the interior, where the enzymes reside.

As a proof-of-principle, the investigators used an enzyme that can remove a sugar molecule from a class of molecules known as purines. Purines are components of nucleic acids such as DNA and RNA, and various chemically modified purines have shown promise as anticancer agents. These compounds are usually toxic to healthy cells, however, so researchers are exploring the use of purine-analog prodrugs as alternative anticancer drug candidates.

In vitro experiments demonstrated that the nanoreactors were able to efficiently convert the prodrugs to active cell-killing compounds. Based on these results, the investigators are now creating nanoreactors coupled to tumor-targeting antibodies and other molecules.

This work is detailed in a paper titled, “Therapeutic nanoreactors: combining chemistry and biology in a novel triblock copolymer drug delivery system.” An investigator from the University of Basel, Switzerland, also participated in this study, which was posted online in advance of print publication. An abstract is available through the journal’s website.
View abstract.