Gene Therapy

1. + Gene Therapy AP Biology Unit 2

2. What is Gene Therapy? • A way to treat or cure diseases by inserting the “correct” DNA into the cell. • Most promising for diseases caused by a single gene defect (ex. hemophilia) • Still in the experimental stages • Clinical trials have been done on humans

3. The Big Picture Image taken without permission from http://www.fda.gov/fdac/features/2000/gene.html

4. Ex vivo • Means it occurs outside of the body • Steps: • Defective cells are taken out of the patient • Add functional gene into defective cells • Return these cells to the patient’s body • Has been used to treat hemophilia, and adenosine deaminase deficiencies (leads to immune system problems)

6. In vivo • Means it occurs in the patient’s body • Insert the genes directly into the patient’s cells • Ex. using an aerosol spray containing functional genes that are are mutated in cancer cells to treat lung cancer. • Still in the early stages of experimentation

7. Challenges • Find appropriate vectors • currently recombinant viruses and plasmids are being tested • Make sure vectors can be taken up by human cells properly • Ensure that new gene is inserted into human genome properly and proteins are expressed correctly • Could be very problematic if it inserts itself in the wrong place and disrupts transcription of a crucial protein

8. More challenges • How to make sure the functional gene gets to all the cells that need it • How to sustain the cells that got the functional gene– cells die after a while! • How to control how the immune system responds to the vector