Ethical aspects of the 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 the field.
It is clear that the field of synthetic biology holds many possible applications in various fields such as agriculture, ecological, environmental fields, and medicine. The field of medicine brings forth 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 (3, 4). 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 (5, 6).
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 (5, 6).
Another ethical concern arising from CRISPR/Cas9 system is human germline modification. 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 (7). This paper appeared online on 18 April in Protein & Cell, a 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" (8), "Embryo engineering study splits scientific community" (9), "Genetic engineering: Editing humanity" (10) and "Don’t edit the human germ line" (11), are only few examples.
In one of the articles mentioned above (11), one of the researchers who helped develop zinc-finger nucleases, a much used genetic engineering technique, 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. However, legitimate concerns regarding the safety and ethical impacts of germline editing must not impede the significant progress being made in the clinical development of approaches to potentially cure serious debilitating diseases (11).
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 (Boomerang design). In our project, we designed a gRNA that will guide dCas9-VP64 to a third plasmid that contains a synthetic promoter which controls the transcription of 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.
Looking at the future
The complex interaction between synthetic biology, genetics and ethics demonstrates the need for an interdisciplinary approach to identify appropriate ethical boundaries to maximize public benefits and minimize risks. As an example, in 2010, President Barack Obama asked the Presidential Commission for the Study of Bioethical Issues (the Commission) to review the developing field of synthetic biology. The committee included among others, scientists, engineers, faith-based and secular ethicists (12).
For a continuation of our, IGEM BGU team activities, we initiated collaboration with Prof. Glick from the Faculty of Health Sciences and Prof. Filk from the department of Politics and Government (Ben-Gurion University of the Negev, Beer-Sheva, Israel), who participate in a newly established Health, Society and Humanism Center. Together, we will organize a meeting to create open dialogue about the science, ethics, and public policy relating to synthetic biology.
(1) Synthetic biology: a Jewish view. Glick S. Perspectives in Biology and Medicine, Volume 55 (4), 2012, pp. 571-580
(2) Some Jewish thoughts on genetic enhancement. Glick SM. J Med Ethics, Volume 37 (7), 2011, pp. 415-419
(3) Identification of genes that are associated with DNA repeats in prokaryotes. Jansen R, Embden JD, Gaastra W, Schouls LM. Mol Microbiol, Volume 43 (6), 2002, pp. 1565-1575
(4) Genetics and ethics: a possible and necessary dialogue. Goldim JR. Journal of Community Genetics, Volume 6 (3), 2015, pp. 193-196
(5) Science policy for all. Is the human germine off limits?
(6) Applications of CRISPR-Cas9 mediated genome engineering. Yang X. Mil Med, Volume 2 (1), 2015.
(7) CRISPR/Cas9-mediated gene editing in human tripronuclear zygotes. Liang P, Xu Y, Zhang X, Ding C, Huang R, Zhang Z, Lv J, Xie X, Chen Y, Li Y, Sun Y, Bai Y, Songyang Z, Ma W, Zhou C, Huang J. Protein Cell, Volume 6 (5), 2015, pp. 363-372
(8) Bioethics. Embryo engineering alarm. Vogel G. Science, Volume 347 (6228), 2015, pp. 1301
(9) Bioethics. Embryo engineering study splits scientific community. Kaiser J, Normile D. Science, Volume 348 (6234), 2015, pp. 486-487
(10) Genetic engineering: Editing humanity. The Economist. 2015
(11) Don't edit the human germ line. Lanphier E, Urnov F, Haecker SE, Werner M, Smolenski J. Nature, Volume 519 (7544), 2015, pp. 410-411
(12) Presidential Commission for the Study of Bioethical Issues. 2010. New directions: The ethics of synthetic biology and emerging technologies.