Introduction
It is important to note that genomic medicine is a discipline that focuses on utilizing and targeting genomic information as a core part of clinical intervention and care. The given research and analysis will assess the most recent and scholarly literature on CRISPR-Cas9 and cancer. The goal is to identify and understand the latest advancements in the field and learn about the new prospects of treating cancer using this genomic treatment method. Thus, CRISPR-Cas9 is highly effective for cancer treatment because it can guide and activate the immune system through the ‘knock out’ method and CAR-T, specifically targeting oncogenes and tumor-suppressor genes and eliminating crucial protein domains.
Cancer and Conventional Treatment Approaches
Cancer incidence and mortality continue to be significant health concerns across the globe. Despite the development of a range of treatments, the unsatisfactory therapeutic outcomes of many cancers highlight the need for expanding the existing arsenal of tools. Surgical procedures, radiotherapy, and chemotherapy are acknowledged, favored, and extensively employed around the globe as cancer treatments (Liu et al., 2023).
Modern advancements have led to the enhancement and development of targeted therapy and photothermal and photodynamic therapies (Liu et al., 2023). However, personalized cancer treatment remains in its early stages. Conventional treatments may result in radiation damage, drug toxicity, and other negative side effects, which can sometimes be fatal (Liu et al., 2023). As a result, there is an urgent need to explore new methods for treating cancer.
CRISPR-Cas9 Overview
To properly understand how groundbreaking CRISPR-Cas9 is, it is essential to start with a basic understanding of the tool. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas9 is a genome editing technique that enables a highly efficient and precise modification of DNA sequences (Zhan et al., 2019). In other words, a “molecular scissor” can make precise and highly target-specific cuts, which are then repaired by internal cellular DNA repair mechanisms.
CRISPR-Cas9 is a transformative instrument that influences the trajectory of genetics and medical research. The guide RNA (gRNA) is a custom-made RNA sequence that steers Cas9 to the exact location in the genome where changes are needed (Zhan et al., 2019). In addition, it is important to note that the gRNA’s complementary RNA bases ensure its binding exclusively to the target DNA sequence. Another fundamental aspect of the system is the Cas9 enzyme, which acts as molecular scissors, cutting DNA at specific sites to facilitate inserting or removing genetic material (Zhan et al., 2019). CRISPR-Cas9 has revolutionized genetic research by providing a straightforward and potent method for gene manipulation.
Literature Review
Immunotherapy has opened a new chapter in treating tumors. Still, its limited efficacy and potential side effects call for further advancements. The emergence of groundbreaking genome editing technology, CRISPR-Cas9, has shown promise in overcoming the limitations of current cancer immunotherapies.
Cancer immunotherapy combats tumor growth and invasion by reinvigorating or activating the immune system (Liu et al., 2023). This approach encompasses various methods, including antibody-drug conjugates (ADCs), dendritic cell (DC) therapy, oncolytic virus therapy, cancer vaccines, cytokine therapy, adoptive cellular immunotherapy (ACT), and immune checkpoint inhibitors (Liu et al., 2023). Thus, these enhanced gene analysis and molecular manipulation technologies can help drive more effective treatment modalities.
Equipping Immune Cells for Precise Activation: CAR-T Method
The literature review reveals several approaches for utilizing CRISPR-Cas9 in cancer therapy. The first major approach is focused on ‘arming’ the immune cells, particularly cytotoxic T-cells. Liu et al. (2023) state that “relevant molecules can be knocked in via CRISPR-Cas9, so CAR-T can ‘arm’ itself to improve the effect of immunotherapy” (p. 3).
In other words, the usually suppressed T-cells become highly capable of identifying tumor cells with the information and signal delivered through the method. The key benefit is that “compared with traditional chemoradiotherapy and other modalities, cell therapies are less toxic and safer if managed properly” (Liu et al., 2023, p. 3). Thus, the given pathway constitutes targeted immune system activation, where a specific category of immune cells is altered and primed to become anti-cancer.
Eliminating Immune Checkpoints for Boosted Immunological Response: The ‘Knock Out’ Method
The second critical method of applying CRISPR-Cas9 in cancer treatment is eliminating immune checkpoints. The key focus is to ‘knock out’ immune inhibitors and immunosuppressive cells to induce a full immunological response without ‘breaks’ (Choi et al., 2019). The target elements primarily include immune checkpoints, such as programmed cell death proteins or PD-1 (Choi et al., 201).
In addition to the checkpoints, the recent findings identified that “certain metabolic regulators, transcription factors, and signaling molecules develop multidimensional immunosuppressive signaling networks that can also lead to T cell dysfunction” (Liu et al., 2023, p. 5). The variety of targets enables a greater ability to modify the treatment regarding its intensity, range, and risks, since eliminating the “immune system’s breaks” cannot be fully safe. However, the latter is still superior to conventional cancer treatment methods, which lack this precision and effectiveness and expose the entire body to chemicals or radiation.
Targeting Oncogenes and Tumor-Suppressor Genes for Improved Detectability and Control
The third major application of CRISPR-Cas9 in cancer treatment is targeting oncogenes. The latter includes genes that promote cell growth and proliferation and, under normal conditions, are controlled by tumor suppressors. However, oncogenes can become resistant to inhibition due to mutations or other factors, making their corresponding cells cancerous.
CRISPR-Cas9 can restore the inhibitory capability of the oncogenes as well as the functional capability of tumor suppressors (Razeghian et al., 2021). For example, TGF-β is known to be the key enabler of immune escape by cancer cells, making them invisible to T-cells, and CRISPR-Cas9 can ‘knock out’ TGF-β, making cancer targetable (Razeghian et al., 2021). As a result, CRISPR-Cas9 can significantly improve cancer cells’ detectability by removing their masking capabilities from the immune system.
Targeting Gene Essentiality for Identification of Crucial Protein Domains
The fourth key approach is centered around the idea of gene essentiality. It is stated that “the concept of gene essentiality can also be narrowed down to gene regions encoding essential protein domains” (Zhan et al., 2019, p. 109). The benefit of the method is that, in contrast to RNAi, which reduces target gene transcripts, CRISPR/Cas9 allows for the disruption of specific protein domains by targeting their respective genomic sequences.
This screening technique, called a domain screen, helps identify protein domains crucial for a gene’s essentiality. CRISPR screening aimed at the exons of chromatin regulatory domains can uncover multiple new domains (Zhan et al., 2019). The latter can be applied in drug development for cancer therapy to make specific elements targetable by drugs.
Challenges and Risks of Using CRISPR-Cas9 for Cancer Therapy
Nevertheless, CRISPR-Cas9’s use for cancer therapy also has a range of roadblocks. The most critical issue with the tool is that CRISPR-Cas9 can over-activate the immune system, inducing an autoimmune disorder. For example, the CAR-T arming method of cancer treatment ‘arms’ cytotoxic T-cells to kill cancer cells (Chen et al., 2019).
However, an incorrect or excessively broad and non-specific activation can also make T-cells aggressive towards healthy cells. In other words, there is a serious risk of major tissue damage or even organ failure. Relying on the immune system to fight against cancer has an inherent danger of over-activating it, creating other health concerns for patients (Chen et al., 2019).
Thus, the challenge is to ensure that immune cells are properly and specifically guided with CRISPR-Cas9. Essentially, the targeting must be broad enough to encompass all cancerous cells but sufficiently specific not to harm healthy cells. Therefore, the experts and professionals in the field need to design effective safety protocols to control this risk of harm.
Similar challenges concerning the “knockout” method of checkpoints can be observed and noted. The immune system relies heavily upon its ability to protect the body in a step-by-step and layered fashion. In other words, the immune system has several protective “walls” against pathogens, from physical barriers, such as skin, to macrophages to T- and B-cells (Khalaf et al., 2020). In each step, critical checkpoints dictate whether or not a subsequent layer of defense requires activation.
CRISPR-Cas9 cancer therapy treatment, based on the ‘knock out’ method, disables these checkpoints to activate deeper layers of the immune system, which poses a risk. The latter can lead to over-activation and rampant autoimmune disorders, which cannot be turned off due to the lack of checkpoints (Khalaf et al., 2020). Thus, when such a method is being considered, it will be important for medical experts to assess whether this tool will benefit or harm the patient.
Lastly, focusing on oncogenes and tumor-suppressor genes directly is challenging primarily due to the complexity of cancer cells. Cells become cancerous by accumulating a series of mutations, allowing them to proliferate uncontrollably. Therefore, several genes, including oncogenes and tumor-suppressor genes, are likely to collectively cause a cell to become a cancer cell.
Knowing which genes to target specifically can be highly problematic since it requires a precise identification down to the sequence to effectively utilize CRISPR-Cas9 (Khalaf et al., 2020). Even creating a human genome library will not be sufficient since individual genome differences make each cancer case unique and individual-specific. The challenge is further complicated by the need to identify all mutations contributing to cancer development. For instance, the cancer might return if this therapy successfully stops cancer cells by targeting a single oncogene or tumor-suppressor gene. The main reason is that all other mutations are ready to make a cancer cell if the targeted mutation reappears.
Personal Opinion and Insight
I believe there will be an explosion of advancements in the cancer therapy field, primarily due to CRISPR-Cas9. My rationale is that it is the most precise method scientists have to target and eliminate the problem at the genomic level. For example, viruses are not as specific since they only deliver genetic materials inside the cell, but CRISPR-Cas9 cuts the problematic areas.
The latter relies on the body’s natural ability to repair DNA breaks, making it not only highly precise but also less disruptive for a cell due to the lack of added genetic material. Viruses can additionally deliver proteins, but their effect will not be as profound as manipulations on the genome level. Thus, I believe that CRISPR-Cas9 is a truly revolutionary tool. Still, it needs a better human understanding of the body, cells, and genes.
The literature review showcased a range of methods of applying CRISPR-Cas9. These include CAR-T, ‘knock out,’ oncogene and tumor-suppressor gene targeting, and gene essentiality targeting. The key insight I drew from arming immune cells for targeted activation through the CAR-T Method is that the immune system can be bolstered and guided with CRISPR-Cas9.
In essence, it opens new frontiers in immunology and immunotherapy, which go beyond cancer and encompass any disease involving the immune system. I think CRISPR-Cas9 can make a wide range of immune cells controllable by humans. Parasitic disease, bacterial infections, and even viral infections can become fully treatable if the immune system is given clear and precise instructions.
It might be possible to stop depending on our excessive dependence on antibiotics, which only creates an ideal condition for highly resistant bacteria. Viral infections are well-known for lacking a proper cure because all we can do is treat the symptoms. However, with CRISPR-Cas9, it is possible to quickly gather core antigen elements and prime immune cells to recognize and attack them.
The COVID-19 pandemic was a major wake-up call for the entire human civilization that viruses pose a danger on par with global issues, such as climate change. Many people died before the vaccine due to weak immune systems, since it was the only defense mechanism people had against viral infections. Even with the vaccine, it still holds since the vaccine simply provides the body with ‘samples’ of the antigen to be prepared for it in the future.
CRISPR-Cas9 can regulate, activate, and prime immune cells more precisely, and it might be possible to induce immune system hyperactivation in anticipation of an infection. The latter leads to my insight into eliminating immune checkpoints for enhanced immunological response through the “knockout” method. Immune system activation and timing are vital for the overall success in combating the disease, especially viral diseases. In patients with suppressed immunity, genomic manipulations of activator genes can enable a greater immune response to antigens.
However, my biggest insight is related to targeting oncogenes and tumor-suppressor genes for improved detectability and control. This method alters the genetics of individual gene levels. The technique can go beyond oncogenes and tumor-suppressor genes to provide gene therapy for people with genetic disorders. Introducing DNA cuts in problematic genes can essentially address an array of genetic diseases, where a gene itself is the cause of the problem.
A similar approach can be applied to autosomal dominant diseases in heterozygous conditions, where CRISPR-Cas9 can cut the problem allele, leaving the healthy recessive allele intact. This could lead to gene therapy capable of curing all autosomal dominant diseases. In addition, if a person is known to be a carrier of an autosomal recessive gene, it can also be targeted. CRISPR-Cas9 essentially needs to know the specific sites to be cut, which can enable the elimination of genetic disorders as we know them.
Conclusion
In conclusion, CRISPR-Cas9 shows great potential in cancer treatment due to its ability to direct and stimulate the immune system using the ‘knockout’ and CAR-T, precisely target oncogenes and tumor-suppressor genes, and target gene essentiality. CAR-T is the use of cytotoxic T-cells, whereas the ‘knock out’ refers to the removal of immune system checkpoints. Targeting oncogenes and tumor-suppressor genes is a more challenging task with greater prospects, whereas gene essentiality is about protein-coding genes.
My thoughts and insights reveal that if CRISPR-Cas9 is fully mastered and developed as a tool of genomic manipulation, both cancer and genetic diseases can become problems of the past. The prospects of these developments are massive, with even greater implications in medicine and healthcare. Despite its current challenges and risks, the benefits far outweigh them. Future developments and improvements will further reduce the problematic aspects of CRISPR-Cas9 while significantly enhancing its capabilities.
References
Chen, M., Mao, A., Xu, M., Weng, Q., Mao, J., & Ji, J. (2019). CRISPR-Cas9 for cancer therapy: Opportunities and challenges. Cancer Letters, 447, 48-55. Web.
Choi, B. D., Yu, X., Castano, A. P., Darr, H., Henderson, D. B., Bouffard, A. A., Larson, R. C., Scarfò, I., Bailey, S. R., Gerhard, G. M., Frigault, M. J., Leick, M. B., Schmidts, A., Sagert, J. G., Curry, W. T., Carter, B. S., & Maus, M. V. (2019). CRISPR-Cas9 disruption of PD-1 enhances activity of universal EGFRvIII CAR T cells in a preclinical model of human glioblastoma. Journal of Immunotherapy Cancer, 7(1), 304. Web.
Khalaf, K., Janowicz, K., Dyszkiewicz-Konwińska, M., Hutchings, G., Dompe, C., Moncrieff, L., Jankowski, M., Machnik, M., Oleksiewicz, U., Kocherova, I., Petitte, J., Mozdziak, P., Shibli, J. A., Iżycki, D., Józkowiak, M., Piotrowska-Kempisty, H., Skowroński, M. T., Antosik, P., & Kempisty, B. (2020). CRISPR/Cas9 in cancer immunotherapy: Animal models and human clinical trials. Genes, 11(8), 921. Web.
Liu, Z., Shi, M., Ren, Y., Xu, H., Weng, S., Ning, W., Ge, X., Liu, L., Guo, C., Duo, M., Li, L., Li, J., & Han, X. (2023). Recent advances and applications of CRISPR-Cas9 in cancer immunotherapy. Molecular Cancer, 22(35), 1-19. Web.
Razeghian, E., Nasution, M.K.M., Rahman, H.S., Gardanova, Z.R., Abdelbasset, W.K., Aravindhan, S., Bokov, D.O., Suksatan, W., Nakhaei, P., Shariatzadeh, S., Marofi, F., Yazdanifar, M., Shamlou, S., Motavalli, R., & Motavalli Khiavi, F. (2021). A deep insight into CRISPR/Cas9 application in CAR-T cell-based tumor immunotherapies. Stem Cell Research & Therapy, 12(1), 428. Web.
Zhan, T., Rindtorff, N., Betge, J., Ebert, M. P., & Boutros, M. (2019). CRISPR/Cas9 for cancer research and therapy. Seminars in Cancer Biology, 55, 106-119. Web.