(July 14, 2015) Scientists have designed nanoparticles that release drugs in the presence of a class of proteins that enable cancers to metastasize. That is, they have engineered a drug delivery system so that the very enzymes that make cancers dangerous could instead guide their destruction.
“We can start with a small molecule and build that into a nanoscale carrier that can seek out a tumor and deliver a payload of drug,” said Cassandra Callmann, a graduate student in chemistry and biochemistry at the University of California, San Diego, and first author of the report published in the journal Advanced Materials July 14.
The system takes advantage of a class enzymes called matrix metalloproteinases that many cancers make in abundance. MMPs chew through membranes, allowing cancer cells to escape to colonize other regions of the body, often with deadly consequences.
Callmann created tiny spheres packed with the anti-cancer drug paclitaxel (also known by the trade names Taxol and Onxal) and coated with a peptide shell. MMPs tear up that shell, releasing the drug. The shell fragments form a ragged mesh that holds the drug molecules near the tumor.
The work, led by Nathan Gianneschi a professor of chemistry and biochemisty at UC San Diego, builds on his group’s earlier sucess using a similar strategy to mark tumors for both diagnosis and precise surgical removal.