CRISPR

CRISPR Claire Spicknall (Year 8) Science Faculty, The Illawarra Grammar School, Western Avenue, Mangerton, 2500

Introduction

Clustered regularly interspaced short palindromic repeats (CRISPR) technology was created in 1987 and became more widely used in 2012. CRISPR allows researchers to easily alter DNA sequences and modify gene function. The protein Cas9 (or "CRISPR-associated") is an enzyme that “acts like a pair of molecular scissors, capable of cutting strands of DNA” (Live Science, 2018). Essentially this means that CRISPR technology allows for scientists to edit and modify the DNA inside human cells. This report will focus on how CRISPR has been used to edit cells within the body to better locate and kill cancerous cells and the advantages and disadvantages to using CRISPR technology.

Metastatic Cancer

CRISPR is a technology used to edit genes in diseases, this report will focus on CRISPR being used to treat metastatic cancer (stage IV cancer). In a healthy body the cells grow, die, and are replaced in a controlled way, this process is called cell division. The genetic material of cells can be damaged by environmental or internal factors and can cause mutated cells to grow uncontrollably, this results in a mass of cancer cells or a tumour, this process is shown in Figure 1. If this is not managed it can then lead to metastatic cancer. This is when cancer cells separate from the original tumour and penetrate the circulatory system and spread through bloodstreams or lymph vessels. The cancer cells then reside on a new part of the body and form a new tumour or cancer cluster, typically on nearby organs or lymph nodes.

Figure 1 shows the abnormal growth of cancer cells and how it forms tumours (Cancer Council, N.D).

9

Effected parts of the body

Cancer can be present and spread almost everywhere in the body, but is most frequently found on the lungs, liver, or bones. When cancer cells spread, they do so by penetrating the circulatory and lymphatic system and flowing through bloodstreams or the lymph vessels where they then collect on a new part of the body and can form another mass of cancer or a tumour, this process is shown in Figure 2.

Figure 2 shows the spread of cancer cells and how it penetrates the blood system and lymphatic system (Cancer Council, N.D).

An example of how CRISPR can be used to treat cancer

Although CRISPR is still a new medical technology it has still been used in numerous experiments to modify DNA within cells. Most experiments in fighting cancer have required modifying the cells within the blood stream. An example of this is the study done by the University of Pennsylvania in 2019 in which CRISPR was used to modify the T cells to better locate and kill the NE-ESO-1 molecule found in most cancer cells. The experiment started by extracting blood from the patients, this was done to reach the T cells, which are white blood cells that have the potential to kill cancer as well as protect the body from infection. The scientists then used CRISPR to add the receptor protein that acts like a claw and will look for the NE-ESO-1 molecules found in cancer cells, once the receptor finds these molecules it will bind to the cell and kill it. CRISPR was also used to remove three genes that limit and/or obstruct the cells ability to kill the targeted NE-ESO-1 molecules found in cancer. Once CRISPR had been fully modified the T cells they were multiplied in the lab and infused back into the patients. The experiment is summarised in Figure 3. The results of this experiment proved CRISPR’s success as there was no evidence to suggest it is not safe to use on patients and for two thirds of patients the T cells slowed or stopped the tumour growth. With more experiments in the future scientists believe that CRISPR could become a successful and commonly used practice to fight cancer.

10

Figure 3 shows how CRISPR is used to edit the T cells and how these T cells kill cancer cells. (National Cancer Institute, 2020)

Social advantages

An important advantage that CRISPR has over other cancer treatments like chemotherapy is that it does not have any known side effects, this decreases the physical and mental toll that cancer treatment has on the patient. This social perspective is important because it means that patients will not have to encounter the numerous side effects (see Figure 4) that chemotherapy can inflict on their body and the physiological damage it can cause. Chemotherapy causes numerous side effects to the patient; this is because the drugs not only kill the cancer cells but may also damage or kill the healthy body cells. This is where CRISPR has the advantage because it does not harm any body cells but instead enhances them to detect and kill cancer more efficiently and effectively, this means no side effects and improves the patients experience with the cancer treatment.

Ethical disadvantages of using CRISPR A significant ethical disadvantage to using CRISPR to edit genes within a cell is that it may in future promote ableism (discrimination in favour of able-bodied people). As CRISPR technology advances so does the human desire to perfect genes and eliminate people with genetic diseases like cancer or disabilities. This raises ethical considerations, like whether this change should even be made by humans in the first place and whether scientists have the right to rewrite the future and change the eggs, sperm, or embryos for the next generation. Many say that the whole ideas of perfecting human genes can be considered ableist as it promotes ideas that people with supposably “bad genes” hold a lesser place in society and should be corrected.

11

Conclusion

In conclusion CRISPR has shown great potential to become a common treatment for cancer given more experiments and a better understanding of the cancer cells and the cells in the body that are able to fight it. There are great social benefits to using CRISPR technology to treat cancer compared to other treatments like chemotherapy, but as any technology advances there will always be weaknesses and the possibility that it may be used in ableist ways to correct “bad genes”.

Figure 4 shows the side effects of chemotherapy (Centre for Clinical Haematology, N.D)

References

How CRISPR Is Changing Cancer Research and Treatment 2020, National Cancer institute, N.a, viewed 31 August 2021, <https://www.cancer.gov/newsevents/cancer-currents-blog/2020/crisprcancer-research-treatment>. Side Effects of Chemotherapy 2020, Centre for Clinical Haematolog, N.a, viewed 2 September 2021, <https://cfch.com.sg/chemotherapy-sideeffects/>. Side Effects of Chemotherapy 2021, Cancer.net, N.a, viewed 1 September 2021, <(the discrimination in favour of able – bodied people)>. What is cancer n.d., Cancer Council, N.a, viewed 29 August 2021, <https://www.cancer.org.au/cancerinformation/what-is-cancer>. what is CRISPR 2018, Live Science, N.a, viewed 27 August 2021, <Side Effects of Chemotherapy 2020, Centre for Clinical Haematolog, N.a, viewed 1 September 2021

12