Molecular farming

Molecular farming (also known as molecular pharming^[1] or biopharming^[2]) is the use of genetically engineered crops to produce compounds with therapeutic value.^[3] These crops will become biological factories used to generate drugs and other difficult or expensive products.^[4] The term pharming can be used to describe plant derived pharmaceuticals, but it is more commonly used for products engineered in animals.^[3] The issue of genetically modified crops has been around for a number of years and continues to be a controversial subject.

History

The first recombinant plant-derived pharmaceutical protein (PDP) was human serum albumin, initially produced in 1990 in transgenic tobacco and potato plants.^[5] Fifteen years on, the first technical proteins produced in transgenic plants are on the market, and proof of concept has been established for the production of many therapeutic proteins, including antibodies, blood products, cytokines, growth factors, hormones, recombinant enzymes and human and veterinary vaccines.^[6] Furthermore, several PDP products for the treatment of human diseases are approaching commercialization, including recombinant gastric lipase for the treatment of cystic fibrosis, and antibodies for the prevention of dental caries and the treatment of non-Hodgkin's lymphoma.^[7] There are also several veterinary vaccines in the pipeline; Dow AgroSciences announced recently their intention to produce plant-based vaccines for the animal health industry.^[8]

Overview

Plant molecular farming uses genetic engineering to produce substances for a variety of uses. Potential products include the development of antigens for vaccines that might be mass-produced in plants such as corn and used to fight such diseases as cancer and diabetes.^[9]

Advantages

Plants do not carry pathogens that might be dangerous to human health. Additionally, on the level of pharmacologically active proteins, there are no proteins in plants that are similar to human proteins. On the other hand, plants are still sufficiently closely related to animals and humans that they are able to correctly process and configure both animal and human proteins. Their seeds and fruits also provide sterile packaging containers for the valuable therapeutics and guarantee a certain storage life.^[10]

Global demand for pharmaceuticals is at unprecedented levels, and current production capacity will soon be overwhelmed. Expanding the existing microbial systems, although feasible for some therapeutic products, is not a satisfactory option on several grounds^[6]. First, it would be very expensive for the pharmaceutical companies. Second, other proteins of interest are too complex to be made by microbial systems. These proteins are currently being produced in animal cell cultures, but the resulting product is often prohibitively expensive for many patients. Finally, although it is theoretically possible to synthesize protein molecules by machine, this works only for very small molecules, less than 30 amino acid residue in length.^[5][10] Virtually all proteins of therapeutic value are larger than this and require live cells to produce them. For these reasons, science has been exploring other options for producing proteins of therapeutic value^[3][6][8].

Disadvantages

Moss bioreactor with Physcomitrella patens

While molecular farming is one application of genetic engineering, there are concerns that are unique to it. In the case of genetically modified (GM) foods, concerns focus on the safety of the food for human consumption. In response, it has been argued that the genes that enhance a crop in some way, such as drought resistance or pesticide resistance, are not believed to affect the food itself. Other GM foods in development, such as fruits designed to ripen faster or grow larger, are believed not to affect humans any differently from non-GM varieties.^{[3][8][9][10]}

In contrast, molecular farming is not intended for crops destined for the food chain. It produces plants that contain physiologically active compounds that accumulate in the plant’s tissues. Considerable attention is focused, therefore, on the restraint and caution necessary to protect both consumer health and environmental biodiversity.^[3]

There are also problems associated with the use of plants as protein bioreactors. Plant proteins have different sugar residues from human or animal proteins. Freiburg-based greenovation Biotech GmbH, in cooperation with Professor Ralf Reski’s research group at the University of Freiburg, has shown that this problem can be solved through the use of Physcomitrella patens. Because the scientists cultivate the moss in moss bioreactors using liquid medium, they have no worries that the genetically modified mosses might be released into the environment.^[4][8][11]

Controversy

The fact that the plants are used to produce drugs is alarming activists. They worry that once production begins, the altered plants might find their way into the food supply or cross-pollinate with clean crops^[9]. Concern arose last year after GMO corn produced by StarLink accidentally ended up in commercial food products. No products produced by plant molecular farming were available in the emerging market,until the first ones were launch around 2006^[12]. Today Molecular Farming is considered "big business". According to the Canadian Food Inspection Agency, in a recent report, says that U.S. demand alone for biotech pharmaceuticals is expanding at 13 percent annually and to reach a market value of $28.6 billion in 2004^[9]. Molecular Farming is expected to be worth $100 billion globally by 2020.^[13]

References

1. ^ Humphreys, J.; Chapple, C. (2000). "Molecular 'pharming' with plant P450s". Trends in Plant Science 5 (7): 271. doi:10.1016/S1360-1385(00)01680-0. PMID 10871897.  edit
2. ^ Miller, H. I. (2003). "Will we reap what biopharming sows?". Nature biotechnology 21 (5): 480–481. doi:10.1038/nbt0503-480. PMID 12721561.  edit
3. ^ ^{a b c d e} Sonya Norris (4 July 2005). "Molecular farming". Science and Technology Division Canadian Library of Parliament. http://www2.parl.gc.ca/Content/LOP/ResearchPublications/prb0509-e.htm. Retrieved 2008-09-11. 
4. ^ ^{a b} "Molecular farming". worldwidewords.org. http://www.worldwidewords.org/turnsofphrase/tp-mol2.htm. Retrieved 2008-09-11. 
5. ^ ^{a b} Sijmons, Peter J. "Production of Correctly Processed Human Serum Albumin in Transgenic Plants". Mogen International NV, Einsteinweg 97, 2333 CB Leiden, The Netherlands.. http://www.nature.com/nbt/journal/v8/n3/abs/nbt0390-217.html. Retrieved 2008-09-13. 
6. ^ ^{a b c} Twyman, Richard M (28 October 2003). "Molecular farming in plants: host systems and expression technology". Science Direct. http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TCW-49W6R98-3&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_version=1&_urlVersion=0&_userid=10&md5=96d839afe2533d0cc04ccf1c1faf682f. Retrieved 2008-09-13. 
7. ^ P, Christou; Ma JK, Drake PM (October 2003). "Genetic modification: The production of recombinant pharmaceutical proteins in plants". Nature Reviews Genetics. http://www.nature.com/nrg/journal/v4/n10/abs/nrg1177.html. Retrieved 2008-09-13. 
8. ^ ^{a b c d} "Molecular farming for new drugs and vaccines". nature.com. http://www.nature.com/embor/journal/v6/n7/full/7400470.html#B17. Retrieved 2008-09-13. 
9. ^ ^{a b c d} Mandel, Charles. "Molecular Farming Under Fire". wired. http://www.wired.com/medtech/health/news/2001/11/48108. Retrieved 2008-09-13. 
10. ^ ^{a b c} "Molecular Farming – Plant Bioreactors". BioPro. http://www.bio-pro.de/magazin/thema/00178/index.html?lang=en. Retrieved 2008-09-13. 
11. ^ "Moss bioreactors do not smell" - Interview with Professor Ralf Reski
12. ^ "Plant molecular farming set to boom?". inpharmatechnologist. 18-Jan-2005. http://www.in-pharmatechnologist.com/Industry-Drivers/Plant-molecular-farming-set-to-boom. Retrieved 2008-09-13. 
13. ^ "Protein Products for Future Global Good". molecularfarming.com. http://www.molecularfarming.com/about.html. Retrieved 2008-09-11. 

External links

• molecularfarming.com Official site
• Molecular Farming – Plant Bioreactors
• Moss bioreactors do not smell (Interview with Ralf Reski)
• Molecular Pharming - pharmaceuticals with the help of GM plants