Engineered proteins direct drugs to difficult tumors


Researchers at Stanford have developed a targeted approach to cancer treatment using not the usual antibodies but engineered proteins to direct drugs to a tumor. The proteins boast several advantages over antibodies, which can be fairly limited in their approach--one such advantage could be their ability to cross the blood-brain barrier and treat cancers there.

Stanford’s Jennifer Cochran first designed a protein based on the knot-shaped knottin protein to bind to molecules known as integrins, which are found on the surface of many tumors. By binding to these molecules, the protein could be used as a highly targeted delivery vehicle. They attached chemotherapy treatments to the new proteins using the antibody techniques of the past.

And besides being effective against breast, ovarian and pancreatic cancer cells in vitro, the compounds have shown to potentially cross the difficult blood-brain barrier, allowing them to act against brain tumors, as well. And the smaller size of the molecule could also give the protein an advantage for denser tumors.

“Antibodies can be limited for treating solid tumors because they are too big to penetrate well,” Cochran said. “The idea is that a smaller molecule could diffuse into the tumor better.”

Cochran and her team are looking further into which compound sizes are most effective for which types of tumor, as well as which chemotherapies work best with the delivery method.

- here's the Stanford release