Personalized cell ‘editing’ used to treat cancer patients: study
- November 13, 2022
- Posted by: OptimizeIAS Team
- Category: DPN Topics
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Personalized cell ‘editing’ used to treat cancer patients: study
Subject :Science and Tech
Context-
- Scientists have, for the first time, used CRISPR technology to insert genes that allow immune cells to attack cancer cells, potentially leaving normal cells unharmed and increasing the effectiveness of immunotherapy.
About the research findings-
- The CRISPR gene editing technique has been previously used in humans to remove specific genes to allow the immune system to be more activated against cancer.
- The research used CRISPR to insert new ones in immune cells efficiently redirecting them to recognise mutations in the patient’s own cancer cells.
- When infused back into patients, these CRISPR-engineered immune cells preferentially traffic to cancer and become the most represented immune cells there.
- The human immune system has specific receptors on immune cells that can specifically recognise cancer cells and differentiate them from normal cells.
Key constraint-
- Immune cells are different for every patient, so finding an efficient way to isolate them and insert them back into immune cells to generate a personalised cell therapy to treat cancer is key to making the approach feasible on a large scale.
- The generation of a personalised cell treatment for cancer would not have been feasible without the newly developed ability to use the CRISPR technique to replace the immune receptors in clinical-grade cell preparations in a single step.
How do researchers resolve those problems-
- The researchers found an efficient way to isolate these immune receptors from a patient’s own blood.
- After isolation, the immune receptors are used to redirect immune cells to recognise cancer using CRISPR gene editing.
What is the CRISPR gene editing technique?
- CRISPR–Cas9 is a unique technology that enables geneticists and medical researchers to edit parts of the genome by removing, adding or altering sections of the DNA.
- It is currently the simplest, most versatile and most precise method of genetic manipulation and is therefore causing a buzz in the science world.
- CRISPR (Clustered regularly interspaced short palindromic repeats) is a family of DNA sequences found in the genomes of prokaryotic organisms such as bacteria and archaea.
- Cas-9 is an enzyme.
How does it work?
- The CRISPR-Cas9 system consists of two key molecules that introduce a change in the DNA. These are:
- an enzyme called Cas9. This acts as a pair of ‘molecular scissors’ that can cut the two strands of DNA at a specific location in the genome so that bits of DNA can then be added or removed.
- a piece of RNA called guide RNA (gRNA). This consists of a small piece of pre-designed RNA sequence (about 20 bases long) located within a longer RNA scaffold. The scaffold part binds to DNA and the pre-designed sequence ‘guides’ Cas9 to the right part of the genome. This makes sure that the Cas9 enzyme cuts at the right point in the genome.
- The guide RNA is designed to find and bind to a specific sequence in the DNA. The guide RNA has RNA bases that are complementary to those of the target DNA sequence in the genome. This means that, at least in theory, the guide RNA will only bind to the target sequence and no other regions of the genome.
- The Cas9 follows the guide RNA to the same location in the DNA sequence and makes a cut across both strands of the DNA.
- At this stage, the cell recognises that the DNA is damaged and tries to repair it.
- Scientists can use DNA repair machinery to introduce changes to one or more genes. in the genome of a cell of interest.