Genetic Modification of Viruses and Cancer treatment

Shadan Abdullah

Our current technological advances are allowing us to modify the genes for every possible organism. Most of the time, this works in our favor to treat long-lasting disorders. As we know, genetics is an important cause of many diseases around the world. However, they’re also a major tool used to treat illnesses that genetics cause. This is done by modifying the specific genes or even a genome. This is valuable to note when it comes to treating cancer. The procedure will carry through many of the current cancer treatments and might be another future solution to other illnesses. The main step done to modify organisms is the isolation of the gene that is intended to be exchanged. This gene will be then inserted into a host genome just like, for example, how CRISPR can insert genes into host genomes. There are many other techniques used to introduce a foreign genetic material into genomes. Bacteria have been known as the easiest to engineer due to their structural simplicity. Many different types of plants are also scientifically engineered in order to make them resistant to particular diseases and enhance the agricultural industry.

 

Thinking closely about the multistep process, the isolated gene is most likely combined with another genetic material such as a promoter and a terminator to make sure it is recognized by the genetic sequence. Promoters are located near the transcription sites of DNA and terminators are a section of the nucleic acid that marks its end. Upon the insertion of these genes into the genomes, they are combined with a selectable marker. The marker can be positive (offers a selective advantage) or negative (inhibits the growth of the host organism). These markers ease the acceptance of the genetic material into the DNA sequence. Now, the techniques used to insert the gene into the host genome depend on the organism. For example, in bacteria, susceptibility to shock or heat has been seen as an effective way to introduce the gene. In animals, microinjection is generally used. Microinjection is seen as an easy way because it is injected through the cell’s nuclear envelope, leading it directly to the nucleus where the DNA lies. For these genes to be regenerated within cells, genetic engineers have to ensure that this inserted gene is present in the embryonic stem cells, which are capable of self-regenerating continuously. In viruses, the process of introducing a gene through a viral infection is called transduction, and the benefit is that different viruses will induce different capabilities and give different results. The most common family of viruses used in the modification are adenoviruses because they are able to carry a large mass of foreign DNA and infect different types of host cells.

How does this all relate to treating cancer?

We know that viruses are altered in a way where they would be still capable of infecting cells.

oncolytic viruses are now established as an important treatment to promote an anti-tumor response against cancer cells. Some of these modified viruses work directly to kill cancer cells while others initiate a systemic immune response against them by “exposing” their antigens. The virus would first infect a tumor cell and replicate inside it until the cell burst. When this cell bursts, the tumor antigens (usually proteins that cause the body to make an immune response against a foreign matter) are released into the surroundings. These antigens will allow cancer to be recognized by the immune system. It’s important to note that after infection, the viruses take over the cell’s ribosomes, and this prevents tumor cells from producing enough proteins in order to grow. The antigens released by these tumor cells will trigger a collection of immune cells including T cells which trigger the activation of Cytotoxic T lymphocytes. Not only will this response destroy infected cancer cells, but also uninfected cancer cells. Bursting cells isn’t the only thing oncolytic viruses are capable of doing. They are also able to destroy the tumor blood vessels. With a disrupted blood supply, the tumor cell will have a lack of nutrients and will be in a state of hypoxia (a below-normal level of oxygen). The good thing about his is that OV viruses only infect cancer cells. Why? It seems that these viruses work directly by the mechanisms of the tumor cell itself. These signals cause an antiviral immune response.  This treatment has been shown to be effective at removing all types of cancer. Through all of this, we see a strong correlation between the advancement of biotechnology and innovation within the pathology field, and the probability of us advancing further will rise higher in the next upcoming years.