Will Chickens Make the Next Cancer Medicine?
Genetically Modified Chickens are Paving the Way
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Genetic engineering has been happening for a few decades, and in 2006 the first drug produced in a transgenic animal was approved for human use. When animals can be used to help produce these medicines, costs tend to be much lower than when the same drugs are produced in a lab. Recent research at the Roslin Institute in Edinburgh, Scotland concerns chicken eggs that contain certain human proteins that can help fight certain types of cancer as well as heal damaged tissues.
Most of the transgenic animals used for producing medicines are milk-producing animals such as sheep, cattle, and goats. Transgenic is another word for genetically modified animals that have a gene from another species inserted into their DNA. These animals were given a gene code so that they produced various human proteins as part of their milk. This is then filtered out through an intricate multi-step process. The high amount of lipids (fat) in the milk often hindered the extraction process. Other factors such as long gestation periods and time to maturity also hindered the progress in developing new medicines and proteins in lactating animals. At the Roslin Institute, their research turned towards eggs.
Some of the benefits of choosing eggs over milk-producing animals include a simpler extraction protocol. Because the desired protein was limited to the egg white, not the yolk, lipids did not impede the extraction of desired proteins. Chickens also mature much more quickly than large mammals, and egg production is generally high and constant. The cost of housing, feeding, and caring for chickens is also much lower than that of larger animals. In fact, because the cost of keeping chickens is so low, the proteins that the Roslin Institute are currently working on producing can be made at one-tenth of the previous cost when they were created solely in a lab. It also only takes three eggs to produce one clinical dose of the medicine.
The chickens that have been developed to lay eggs containing special human proteins do not know that they are anything special. They lead normal lives in a comfortable coop eating and laying eggs. Having the human protein gene does not affect their health in any way. The gene only affects the egg white protein. Also, before you worry about GMO eggs ending up in your food supply, know that these eggs are still so valuable (and the chickens too) that they will never accidentally end up in a supermarket. Years of research have already been put into developing these chickens, and it will probably be 10-20 more years of research, testing, and fine-tuning before the proteins being produced will even be approved for human use.
The first of the two human proteins being produced in these eggs is called interferon alpha2a (IFNα2a). It is a cytokine dimer that helps regulate the immune response of the body. This type of protein is usually secreted by certain immune cells called leukocytes in response to a virus. It can tell the nearby cells to activate their anti-viral defenses as well as help to inhibit virus replication. It is already used to help treat viral infections as well as leukemia, AIDS-related Kaposi’s sarcoma, and Hepatitis C. In initial testing, this egg-derived IFNα2a was actually more effective that the lab-grown bacterially-derived equivalent.
The second of the two human proteins produced in the eggs is Macrophage colony-stimulating factor (CSF1). CSF1 is a cytokine that stimulates certain stem cells to become macrophages or other related cells. A macrophage is a white blood cell that basically eats and digests foreign contaminants, cancer cells, bacteria, and viruses. This protein is being studied for use in both cancer treatment and in the repair of damaged tissues.
The results of this research are very promising to the medical community. Not only does this show that these particular cancer-fighting medicines can be produced in a more cost-effective way than before, but it paves the way for other medicines and therapeutic proteins to be produced in a humane and cost-effective manner. Hopefully, the increased cost-effectiveness will trickle down to the costs that patients have to pay to receive these therapies. The researchers in this study are also excited about the potential for medicines for other animals to be produced in this manner. One such product that researchers hope to produce would be an immune-boosting drug for farm animals to help prevent the overuse of antibiotics.
The road for these medicines to be produced for human use is long and filled with many safety studies among other tests. One piece of good news is that due to the purification process, the researchers could not detect any egg protein leftover in the purified IFNα2a or CFS1 proteins. Hopefully, this will be good enough for those with allergies to egg protein, but I anticipate that this will be included in the safety studies of the medicine. What do you think of chickens producing life-saving medicines and therapies?
Herron, L. R., Pridans, C., Turnbull, M. L., Smith, N., Wear, M., Kurian, D., et al. (2018). A chicken bioreactor for efficient production of functional cytokines. BMC Biotechnology.
Middleton, J. (2019, January 28). Hen eggs with human proteins offer drug hope. Edinburgh, Scotland, United Kingdom.
Originally published in the June/July 2020 issue of Backyard Poultry and regularly vetted for accuracy.