Ethical aspects of Boomerang system

Along the way of developing our “Boomerang system” we wanted to learn more about the ethical questions that may arise. During the summer we had several meetings with experts from the field of Bioethics that gave us new insights related to this field.

Prof. Shimon Glick from the Faculty of Health Sciences (Ben-Gurion University of the Negev, Beer-Sheva, Israel), is an expert in the field Jewish medical ethics. In our meeting, Prof. Glick shared with us his knowledge regarding Synthetic Biology. In a paper he published recently:” Synthetic Biology: A Jewish View” (ref). he describes several issues related to Synthetic Biology, such as ethical, biosafety and biosecurity concerns. Also, in his publication, and in previous publication related to genetic enhancement there is an interesting aspect of Jewish approach to some ethical issues posed by this new technology (ref).

It is clear that the field of synthetic biology holds many possible applications in various fields such as agriculture, ecological and environmental fields, and medicine. However, this field brings controversial questions for both bioethics and philosophy of medicine.

One of the new and exciting techniques in synthetic biology is CRISPR (clustered regularly interspaced short palindromic repeats), which is used to edit portions of the genome. The classic application of CRISPR is introduction of double strand breaks, and is widely used in the laboratories around the world with more than 1300 papers have been published from its introduction in 2002 (Ref- Jansen et al. 2002)(5). CRISPR/Cas9 system can edit genes with high accuracy and is considered one of the most significant discoveries in science with a potential to treat and even cure several major diseases such as sickle-cell anemia, HIV, and many forms of cancer (1, Applications of CRISPR-Cas9 mediated genome engineering).

A major concern in the application of CRISPR-Cas9 technology is the targeting specificity of Cas9 nucleases. A number of studies have shown that Cas9 could tolerate some mismatches between the guide RNA and its complementary target DNA sequence, causing potential off-site targeting.

Another ethical concern arising from CRISPR/Cas9 system is human germline modification (1,3). These alterations could have unpredictable effects on future generations. In a controversial paper from last April, published by scientists in China, the researchers attempted to edit the genomes of human embryos using CRISPR (ref). This paper appeared online on 18 April in Protein & Cell, a little-known journal co-published by Springer and an affiliate of China's Ministry of Education, but drew widespread attention only after Nature News reported it on 22 April. This publication lead to broad discussions on the risks and benefits of genome editing, and triggered a public backlash. "Embryo engineering alarm" (ref), "Embryo engineering study splits scientific community" (ref), "Genetic engineering: Editing humanity" (ref) and "Don’t edit the human germ line" (ref), are only few examples.

In one of the articles mentioned above (ref), one of the researchers who helped develop zinc-finger nucleases, Edward Lanphier, and four colleagues, call for a moratorium on any experiments that involve editing genes in human embryos or cells that could give rise to sperm or eggs. “Should a truly compelling case ever arise for the therapeutic benefit of germline modification, we encourage an open discussion around the appropriate course of action,” they write. Clearly, with the developing field of synthetic biology novel ethical solutions and guidelines should be used.

Coming back to our "Boomerang project", we designed cancer-specific CRISPR/Cas9-mediated activation of the gene of interest. For that we used a novel feature of CRISPR which is the activation application of Cas9. A catalytically inactive Cas9 (dCas9) is fused to a transcription activation domain and can increase transcription of a gene of interest (link to design). In our project, we designed gRNA that will guide dCas9-VP64, to a third plasmid that contains synthetic promoter and any gene of interest. From the previously mentioned ethical concerns, our approach should avoid any interference with the host genome by directing the activation complex to a third plasmid.

Moreover, Boomerang system is under the control of cancer-specific promoters, so CRISPR activation system will be activated only in cells with the hyperactivation of these promoters. CRISPR is composed of two components- the protein, Cas9, and gRNA. In cells with hyperactivation of only one cancer-specific promoter (a situation that can be found in healthy cells), our Boomerang system won't be activated because each single component is ineffective on its own.

References

(1) Science policy for all. Is the human germine off limits? Thomas Calder, Ph.D. https://sciencepolicyforall.wordpress.com/tag/crisper-cas9/

(2) Synthetic biology: a Jewish view. Prof. Shimon Glick. Perspectives in Biology and Medicine, Volume 55, Number 4, Autumn 2012, pp. 571-580 (Article)

(3) The Economist. Genetic engineering .Editing humanity. A new technique for manipulating genes holds great promise—but rules are needed to govern its use. August 22^nd 2015

(4) Addgene - https://www.addgene.org

(5) Genetics and ethics: a possible and necessary dialogue

BIOETHICS Embryo engineering alarm Science 20 March 2015:
Vol. 347 no. 6228 p. 1301
DOI: 10.1126/science.347.6228.1301

(6) Jansen et al. 2002 cripsr

(7) Embryo engineering study splits scientific community

Science 1 May 2015:
Vol. 348 no. 6234 pp. 486-487
DOI: 10.1126/science.348.6234.486