What is the Difference Between CAR-T and CRISPR

The key difference between CAR-T and CRISPR is that CAR-T is an immunotherapy developed to treat hematological malignancies using a patient’s own immune cells, while CRISPR is a recent gene-editing tool adapted from a naturally occurring immune system in bacteria.

Cancer is a result of abnormal cell growth, and it is one of the leading causes of death around the world. There are different types of cancers. Blood cancer or hematologic cancer is one such cancer, which is very difficult to treat and cure.

CAR-T cell therapy is an immunotherapy method that can treat blood cancers. Generally, cancer cells have antigens. In CAR-T cell therapy, T cells are genetically modified to produce chimeric antigen receptors on their surfaces, which can recognize specific antigens on cancer cells and attack. CRISPR is an immune system naturally occurring in bacteria against viruses and other pathogens. It consists of two RNA types and Cas proteins. CAR-T and CRISPR can be combined together in order to overcome challenges in CAR-T cell therapy when targeting only cancer cells.

CONTENTS

1. Overview and Key Difference
2. What is CAR-T  
3. What is CRISPR
4. Similarities – CAR-T and CRISPR
5. CAR-T vs CRISPR in Tabular Form
6. Summary – CAR-T vs CRISPR

What is CAR-T?

Chimeric Antigen Receptor T cells therapy is an immunotherapy developed to treat haematological malignancies such as blood cancers. This strategy uses the immune effect of T cells. It is done by the transformation of T cells using the genetic engineering technique. Therefore, CAR-T works against cancers by using the patient’s own T cells.

T cells should be separated out from the patient’s blood first. Then, T cells should be genetically engineered, introducing a new artificial gene to produce receptors on their cell surfaces. These receptors are called chimeric antigen receptors or CARs, and they are man-made. Once they are formed, these receptors are able to recognize and attack antigens (specific proteins) on tumor cells. Genetically engineered T cells target and attack specific cancer cells. Sufficient amounts of CRA-T cells are grown in the lab and given to the patient as an infusion. Generally, cancer cells have antigens. Our immune cells do not possess receptors to recognize them. Hence, CAR-T therapy is a novel technology for treating cancers.

Figure 01: CAR-T

This immunotherapy is a promising curative strategy in the treatment of hematological and solid malignancies. However, similar to other cancer treatments, CAR-T also shows different side effects. Some of the side effects of CAR-T are cytokine release syndrome (CRS), massive release of cytokines into the bloodstream leading to high fever and drops in blood pressure, B-cell aplasia and swelling in the brain, or cerebral edema.

What is CRISPR?

Clustered regularly interspaced short palindromic repeats or CRISPR is an effective gene-editing technology. It can be used to make genetic modifications in genomes. It is a widely used gene-editing tool in scientific research in knock-out or knock-in genes in the mammalian genome.

CRISPR sequences are derived from the DNA of a bacteriophage that had previously attacked bacteria. These sequences are used as memories to detect and destroy viral DNA in subsequent infections. CRISPR/Cas9 is a naturally occurring defense mechanism in bacteria and archaea against viral pathogens. There are two types of RNAs (crRNA and tracrRNA) in CRISPR, and there are CRISPR associated proteins (Cas proteins). When guided by the RNA, Cas9 protein can create double-strand breaks in target sequences disabling the viral DNA by introducing mutations by the cell’s natural repair mechanism, especially by the non-homologous end-joining.

Figure 02: CRISPR

This mechanism is used in genomic editing in human cells in order to cleave a gene of interest. It is recognized as simple, easy to use, faster, cheaper and the most efficient gene-editing tool. In 2020, a Nobel Prize was given for the discovery of the CRISPR/Cas9 genome editing system.

What are the Similarities Between CAR-T and CRISPR?

• CAR-T and CRISPR can combine together in order to unleash the therapeutic potential of CAR T cell therapy.
• Both CAR-T and CRISPR use genetic engineering techniques.

What is the Difference Between CAR-T and CRISPR?

CAR-T is an immunotherapy developed to treat hematological malignancies, while CRISPR is a novel gene-editing tool. So, this is the key difference between CAR-T and CRISPR. Moreover, in CAR-T cell therapy, T cells are genetically engineered to produce chimeric antigen receptors on their cell surfaces. Whereas, in CRISPR, RNAs guide Cas proteins to cleave viral DNA in order to disable viral genes. Besides, CAR-T is mainly used to treat cancers whereas CRISPR is used for gene editing.

The below infographic lists the differences between CAR-T and CRISPR in tabular form for side by side comparison.

Summary – CAR-T vs CRISPR

In CAR-T cell therapy, T cells are engineered to produce chimeric antigen receptors (CARs) to recognize and attack specific antigens on cancer cells. CAR-T cell therapy is an immunotherapy developed to treat cancers, especially blood cancers. CRISPR is an immune system seen in bacteria and archaea against viral pathogens. CRISPR is used as a novel gene-editing tool in order to do genetic modification to treat certain diseases. Thus, this is the summary of the difference between CAR-T and CRISPR.

Reference:

1. Liu, Jie, et al. “Building Potent Chimeric Antigen Receptor T Cells with CRISPR Genome Editing.” Frontiers, Frontiers, 1 Jan. 1AD.
2. “CRISPR, CAR-T, and Cancer.” CRISPR, Car-t, and Cancer, 27 Oct. 1970.
3. “Car T Cells: Engineering Immune Cells to Treat Cancer.” National Cancer Institute.

Image Courtesy:

1. “CAR T-cell Therapy” By Reyasingh56 – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “4QYZ” By Boghog – Own work (CC BY-SA 4.0) via Commons Wikimedia

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