Use of Insect Virus in Safer Stem Cell Therapy

As discussed in class today, stem cells are promising candidates for tapping the human body's own potential to repair itself. Many applications of stem cells in regenerative medicine involves integration of genes into human embryonic stem cells (hESCs) that direct the cells in exhibiting a desired therapeutic function. However, gene integration is not always accurate; it can be random. While integration of these therapeutic genes is important, inaccurate integration can lead to several problems. The gene integration into the hESCs may interfere with the correct sequence of DNA and create undesired sequences that cause the hESCs to reproduce too rapidly, and form a tumor, fail to differentiate into the desired form, fail to exhibit desired functions, or malfunction and die.
Thanks to scientists, driven by the need for a safe method to insert therapeutic cancer-killing genes into hESCs, at the Institute of Bioengineering and Nanotechnology (IBN), these malfunctions may be closer to a thing of the past. Researchers have discovered a method of accurately integrating therapeutic genes into a specific region of DNA--site 1 locus (AAVS1)--that, when altered, exhibits no known adverse effects. AAVS1 has been the target of genetic engineering in the past due to its unharmful post-alteration nature. The two previously discovered methods for integrating into this region, however, were inaccurate in one method, and toxic to humans in the other.

The method discovered by the researchers uses a baculovirus, an insect virus, to insert DNA into the AAVS1 region with 100% accuracy. The researchers demonstrated successful homologous recombination of AAVS1 in hESCs (the DNA can be reproduced without change) and use the insect virus to target and splice DNA into specific regions utilizing the Cre/loxP recombinase system (see http://en.wikipedia.org/wiki/Cre-Lox_recombination). The researchers' method is inherently safer than previous random insertion because baculoviruses are specific to insects and do not insert themselves randomly into human DNA. (Patients won't catch a "bug" from this treatment, ahahaha).
Hopefully this method for integrating therapeutic genes will provide for great improvements in the future of regenerative medicine and cancer treatment.

article: http://insciences.org/article.php?article_id=10253#pics