Directing Venom To Fight Cancer

Venom from scorpions or honeybees sounds like it wouldn’t do a person much good. But by directing a modified component just to tumors, researchers might leverage it into a drug.

Peptides in some venoms bind to cancer cells and block tumor growth and spread. But they have not yet been developed successfully as anticancer agents because they attack healthy cells too.

Bioengineer Dipanjan Pan and coworkers at the University of Illinois, Urbana-Champaign, are now using polymeric nanoparticles to deliver venom toxin directly to cancer cells.

Postdoc Santosh K. Misra discussed the work in a session in the Division of Colloid & Surface Chemistry at the American Chemical Society national meeting last week in San Francisco. And Pan, Misra, postdoc Mao Ye, and grad student Sumin Kim reported on it in a paper last month (Chem. Commun. 2014, DOI: 10.1039/c4cc04748f). “To the best of my knowledge, a rational approach to develop a delivery system for venom toxin” has not been tried before, Pan told C&EN.

The researchers inserted a derivative of TsAP-1, a toxin peptide from scorpion venom, into spherical polymeric nanoparticles, creating constructs they call NanoVenin. When they used NanoVenin to treat cancerous tissue in the lab, it spared red blood cells (erythrocytes) and other normal cells and killed cancer cells with a potency nearly 10 times that of the toxin alone.

They have also found that a nanoparticle-encapsulated version of melittin, a honeybee venom toxin, serves as an effective cancer drug. The venom-laden nanoparticles killed breast cancer cells without detrimental effects to normal cells, Pan said.

“We have known for some time that venom toxins have anticancer potential, if only we could deliver them safely and selectively to tumors,” said David Oupicky, codirector of the Center for Drug Delivery & Nanomedicine at the University of Nebraska Medical Center.

The Pan group’s modified scorpion toxin “is new, and the method of incorporation into nanoparticles is fairly new as well,” he added. The finding that it “works against cancer cells but appears not to damage erythrocytes is an important step toward practical application. It will be very interesting to see how the particles behave in vivo.”

Pan said he and his coworkers plan to carry out in vivo tests in rats and pigs and that a start-up he founded, VitruVian Biotech, could start human clinical trials in three to five years.