About gene editing

This is the article I looked at:
https://www.sciencenews.org/article/gene-editing-helps-baby-battle-cancer?tgt=nr

What is this all about?
Gene editing has in the last years become an increasinlgy popular way to find a treatment against cancer. This scientific technique uses a scalpel, which cuts DNA and edits genes, which are disadvantagous in the fight against cancer. Popular scalpels that are used for this treatment are among other things zinc finger nucleases, TALENs, CRISPR and Cas 9. I will specify in this blog on the 'TALENs' method.

What does TALENs do?

• it is a pair of proteins
• it is engineered by scientists to latch onto DNA
• it cuts the DNA at specific sites

How is TALENs used in cancer treatment?

• it engineers immune cells, so that they will kill the cancer without harming body cells
• Immune cells (CART cells) help to recognise foreign cells and destroy them

What happenes in the case study of Layla, which is the first case ever tested with the TALENs method?

• her bone marrow had too many B cells
• these cells are studded with a protein, called DC19
• CART cells were engineered to carry an antibody, which tracks and killes cells with DC19
• How could that be done:
  1. by inserting antibody into T-cells to create CART cells, but this is not possible, because Layla had bone marrow of a donor transplant and not her own one
  2. T-cells of another donor can't be used because they would be recognized as foreign
  3. Universal CART cells can be inserted

Qasim of the University College of London found a solution:

• the team inserted a protein called 'T cell receptor alpha chain' into the T cells
• this makes the T-cells unable to distinguish body cells from foreign ones
• therefore they will just attack cells carrying CD19

How the the foreig cells can be received by the body:

• the scientists used a different pair of TALENs
• this was engineered to remove the protein called CD 52 of the CART cells
• if it is cut out, the cells are invisible to the immune system
• this treatment would therefore kill the patient's own T-cells and let the donor T-cells grow

What is the conclusion of this trial?
After the treatment, Layla's bone marrow contained 90% donated cells, 7% CART cells and 3% of her own cells.
This means, that the T-cells have probably helped to cure her and the study was announced at the 6th of november 2015, so that in one year's time the doctors can conclude if the treatment could have been 'curative'.