US scientists might have achieved a major breakthrough in gene therapy through genetically engineered spider silk. The new material could help overcome a major barrier to the use of gene therapy in everyday medicine. The study has been reported in ACS' journal Bioconjugate Chemistry.
David Kaplan and colleagues at the Tufts University note that 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 focused on one promising prospect, silk proteins, which are biocompatible and have been used in everyday medicine and medical research for decades.
Spider silk is one of nature's most extraordinary substances. It is exceptionally flexible, elastic, and lightweight, yet tough—three times as strong as Kevlar and five times as strong as steel! And because it is natural, it is biodegradable and can be produced pollution-free. Furthermore, one of the most important qualities of spider silk is its endless versatility. Spider silk, synthetically made, could be used in countless applications with significant commercial impact and improvement to human life.
Previously scientists had discovered the genetic sequences for the spider proteins that are used to make spider silk. Wyoming varsity researchers have made synthetic genes that may allow them to alter the proteins and produce silks that are even stronger and more elastic than naturally made silks and allow for "custom-made" silks with specific properties for use in different applications.
In their new research, David Kaplan and others of the Tufts explain modifying spider silk proteins so that they attach to diseased cells and not healthy cells. They also engineered the spider silk to contain a gene that codes for the protein that makes fireflies glow in order to provide a visual signal (seen using special equipment) that the gene has reached its intended 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 the genetically-engineered spider-silk proteins represent "a versatile and useful new platform polymer for nonviral gene delivery," the article notes.