Global Challenges/Chemistry Solutions

Combating Disease: Genetically-engineered spider silk for gene therapy

November 14, 2011

lab mice

Fluorescent signals indicate that a gene
in a gene therapy experiment has
successfully reached its target
— human breast cancer cells
growing in lab mice.
Credit: American Chemical Society.

Summary

Genetically engineered spider silk could help overcome
a major barrier to the use of gene therapy in everyday
medicine, according to a new study that reported
development and successful initial laboratory tests
of such a material. It appears in ACS’ journal
Bioconjugate Chemistry
.

Gene therapy — the use of beneficial genes to prevent or treat disease — 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, published in the ACS journal Bioconjugate Chemistry, focused on one promising prospect, silk proteins, which are biocompatible and have been used in everyday medicine and medical research for decades.

Here’s the study’s lead author David Kaplan, Ph.D., of Tufts University …

“We modified spider silk proteins so that they attach to diseased cells and not to healthy cells. We also engineered the spider silk to be able to carry a gene that codes for a protein that makes fireflies glow so that we 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.

“The results suggest that genetically-engineered spider-silk proteins represent a versatile, very highly tailorable and useful new platform polymer for nonviral gene delivery.”

Smart Chemists/Innovative Thinking

Smart chemists. Innovative thinking. That’s the key to solving global challenges of the 21st Century. Please check out more of our full-length podcasts on wide-ranging issues facing chemistry and science, such as promoting public health, developing new fuels and confronting climate change, at www.acs.org/GlobalChallenges Today’s podcast was written by Katie Cottingham. I’m Adam Dylewski at the American Chemical Society in Washington.

David Kaplan, Ph.D.
David Kaplan, Ph.D.,
Tufts University,