Nov 17 2011
A new episode in the American Chemical Society's (ACS) award-winning "Global Challenges/Chemistry Solutions" podcast series spins a real-life tale in which spider silk shows promise for overcoming a major barrier to the use of gene therapy in everyday medicine.
The new installment from the world's largest scientific society explains in non-technical language that gene therapy involves the use of beneficial genes to prevent or treat disease. It requires safe and efficient carriers or "vectors." Those carriers are the counterparts to pills and capsules, transporting therapeutic genes into cells in the body. Safety and other concerns surround the experimental use of viruses to insert genes. The lack of good gene delivery systems is a main reason why there are no FDA-approved gene therapies, despite almost 1,500 clinical trials since 1989. The new study focused on one promising prospect, silk proteins, which are biocompatible and have been used in everyday medicine and medical research for decades.
David Kaplan, Ph.D., notes in the podcast that he modified spider silk proteins so that they attach to diseased cells and not to healthy cells. He also engineered the spider silk to be able to carry a gene that codes for a protein that makes fireflies glow so that they could provide a visual signal - that's seen with specialized equipment - that the gene has reached its intended cellular target.
In lab studies using mice containing human breast cancer cells, the spider-silk proteins attached to the cancer cells and injected the DNA material into the cells without harming the mice. Kaplan says that the results suggest that genetically-engineered spider-silk proteins represent a versatile, very highly tailorable and useful new platform polymer for nonviral gene delivery.