The Mosaic Viruses
Mosaic viruses are a group of plant viruses that cause speckles on the leaves of the infected plants (hence the name). Mosaic viruses can infect a myriad of plants, such as tobacco, tomato, pepper, cucumber and many more. In most cases, the virus does not kill the infected plant, but it does stunt its growth.
A mosaic virus has its genetic information encoded in RNA rather than DNA. This genetic information is contained in a protein structure called the capsid. This structure of this capsid can be relatively simple, such as a rod, or more complex.
These viruses are often regarded as a pest, but now it seems that they can be quite useful in bioengineering. The latest research is looking into the use of the mosaic virus in cancer therapy.
A Virus As Cancer Therapy
A problem with many common cancer therapies, such as radiation or chemotherapy, is that these are not focused on the cancer itself, but rather attack the entire body, hoping that the cancer will succumb first. So, lately, research has been increasingly investigating more targeted approaches in cancer therapy, which effectively attack and kill the cancer tissue, while leaving the surrounding, unaffected tissue unharmed.
One of the avenues that is being pursued in this line of research, is the use of the mosaic virus in cancer therapy. By emptying the capsid of the viral genetic information, and subsequently filling it with chemical substances that can be used as cancer treatment, these virus capsules can be used as ‘vehicles’ delivering their cancer fighting ‘cargo’ at the right place.
This targeted drug delivery can be achieved through the different coat proteins that are found on the outside of the capsid. These proteins can be used and/or adapted (proteins can even be removed or added to the outside of the capsid) to act as ‘searching devices’ that attach to specific receptor molecules, or cancer-cell specific receptors.
At present, it is already possible to remove the viral RNA from the mosaic virus capsids, and fill them up again with cancer fighting agents. The main goal now is to find or construct a combination of coat proteins that can provide an optimal ‘search and destroy’ strategy.
- Aljabali, A.A.A.; Barclay, J.E.; Butt, J.N.; Lomonossoff, G.P. & Evans, D.J. (2010). Redoc-active ferrocene-modified Cowpea mosaic virus nanoparticles. Dalton Trans. 39, pp . 7569 – 7574.
- Miermont, A.; Barnhill, H.; Strable, E.; Lu, X.; Wall, K.A.; Wang, Q; Finn, M.G. & Huang, X. (2008). Cowpea mosaic virus capsid: a promising carrier for the development of carbohydrate based antitumor vaccines. Chemistry. 14(16), pp. 4939 – 4947.
- Tang, Y.; Wu, H.; Ugai, H.; Matthews, Q.L. & Curiel, D.T. (2009). Derivation of a Triple Mosaic Adenovirus for Cancer Gene Therapy. PLoS One. 4(12): e8526.doi:10.1371/journal.pone.008526.
- U.S. Department of Health and Human Services, National Institutes of Health & National Cancer Institute (January 2004). Cancer Nanotechnology.(https://nano.cancer.gov/objects/pdfs/Cancer_brochure_091609-508.pdf)