TeachableMedicalNews article 12082020

Teachable moment in classrooms:

  1. cellular basis of life chapter – chromosomes contain many genes
  2. cellular basis of life chapter – a gene is a specific stretch of DNA that encodes one protein
  3. cellular basis of life chapter – concept of gene mutation leading to protein

malfunction

  1. immune system chapter – function of T lymphocytes (T cells)

The news item: Recently the gene editing approach to cancer fighting was in the news:

Doctors try CRISPR gene editing for cancer, a 1st in the US

The first attempt in the U.S. to use the gene editing tool CRISPR against cancer seems safe, but it’s too soon to know if it will improve survival.

The report described an experimental treatment of one sarcoma patient and two multiple myeloma patients with the Crispr technology. The article states that this approach deletes 3 genes and adds one gene to the T cells of the patients, and the gene-edited T cells are infused back into the body of the patients.

So, Why Do I Care??

The thing to care about is the potential of the technology of gene editing.  While experimental in humans, and the targets of the technology are relatively rare diseases, if proven useful there are many human genetic disorders that may be managed or cured by it. Any disorder that is caused by mutated genes and malfunctioning proteins may be the future target of gene editing.

Plain English, Please!!!

First, let’s talk about multiple myeloma and sarcoma. Myeloma is a cancer that forms in the red bone marrow. Sarcoma is a cancer that starts from connective tissue. Chemotherapy and other conventional cancer treatments are not very effective against these cancers, and that is why patients were enrolled in this study.

Second, let’s talk about the Crispr technology of gene editing. If we think about a chromosome as a book of genetic information, then a gene would be a chapter in that book. The Crispr technology uses molecule-size scissors (restriction enzymes) to cut out or insert entire genes, DNA chapters, in a chromosome. Because at present time we don’t know enough about the genes of cancer cells, we don’t know all the chapters that gone bad, thus the gene editing is not done on cancer cells trying to change them back to normal cells.  Rather, the gene editing in this study wants to improve the cancer killing ability of T cells of the cancer patient.

Third, let’s talk about T-cells. T lymphocytes are the cells of our immune system, and these cells can search out and destroy abnormal and cancerous cells in our bodies. Some cancer cells escape the T-cells by hiding their abnormal proteins, or by slowing down the energetic T-cells. The Crispr editing in this study removed three genes (and therefore three proteins) that may slow the action of the T cells against cancer cells. On the flipside, one gene (and therefore one protein) was added to improve the T cells ability to recognize the patients’ cancer cells. After the gene editing in the lab, the modified T cells are infused back to the patient.

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