George Church's team publishes cover article: Safely implanting therapeutic genes into the human genome

Through so-called "genomic safe harbors" (GSHs), many future gene and cell therapies for the treatment of cancer, rare genes and other diseases may be enhanced in terms of efficacy, durability and predictability

However, finding GSHs with clinical translation potential is as difficult as finding lunar landing sites for spacecraft—lunar landing sites must be in smooth and accessible areas, not too steep, surrounded by large hills or cliffs that provide good visibility and the ability to return safely

Only a few candidate GSHs have been explored so far, and they all come with certain caveats

Now, a collaboration of researchers at Harvard's Wyss Institute for Biologically Inspired Engineering, Harvard Medical School (HMS), and ETH Zurich, Switzerland, has developed a computational method to identify therapeutic genes with significantly higher safety and A GSH site that is persistently expressed in many cell types

"While GSHs can serve as general platforms for gene targeting, thereby accelerating the clinical development of gene and cell therapies, until now, no location in the human genome has been fully validated, and all of these have been limited to research applications

The researchers first built a computational pipeline to predict regions of the genome that could potentially serve as GSHs by leveraging the vast amount of available sequencing data in human cell lines and tissues

As a graduate student, Aznauryan started the project with other members of Sai Reddy's lab at ETH Zurich's Department of Biosystems Science and Engineering, after which he visited the Church lab as part of his graduate work, where he worked with Wyss Technology Development researcher Denitsa Milanova, who has since joined Church's team as a postdoctoral researcher

The research team randomly selected 5 of the 2,000 confirmed GSHs sites, and inserted the reporter gene into them using the fast and efficient CRISPR-Cas9 gene editing technology in ordinary human cell lines

focus on clinical

To evaluate the two most compelling GSHs in human cell types of interest for cell and gene therapy, the team conducted studies in immune T cells and skin cells, respectively

We introduced fluorescent reporter genes into two new GSHs in human primary T cells obtained from blood and a fully functional LAMB3 gene (extracellular protein in skin) into human primary dermal fibroblasts the same GSHs, and long-lasting activity was observed

"Our extensive sequencing analysis of naive human T cells engineered with GSHs clearly shows that this insertion has the minimal potential to lead to tumor-promoting effects, which has been genetically engineered into cells for therapeutic use," said Reddy.

"This interdisciplinary collaborative effort demonstrates the power of integrating computational approaches with genome engineering while maintaining a focus on clinical translation
.
The discovery of GSHs in the human genome will greatly facilitate future efforts to develop therapies focused on engineering of more effective and safer gene and cell therapies,
” said Donald Ingber, MD, founding director of Wyss
.

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