GENE THERAPY

How do you put the genes into the cell?

1. Liposomes: First of all you must have the gene, by which we mean only the cDNA. Also, you must have the promoter (a small piece of cDNA that promotes transcription). One way would be to put the cDNA and promoter into detergent to break the cell membrane and sneak the gene in. This method is safe, but not effective. If you have a cell culture, you can get the cDNA in maybe 5 or 10% of the cells.

2. There are retroviruses and adenoviruses that can be used to deliver the gene. You must work with the genome of the virus in such a way that the genome incorporates the cDNA and promoter into it. Then you make this virus proliferate in a certain cell line, with the cDNA still inside. This is 100% effective, but hard to do. The retrovirus requires cells that are proliferated, will put this gene into the genome of the cells you are treating. The adenovirus however, will do it in all kinds of cells but will not put the gene into the genome, only into the nucleus

Example: Brain tumor

We have a virus and want to add a tyrosine kinase enzyme, so inject that in the tumor while at the same time giving a drug, ganciclovir. Because this virus goes only into proliferating cancer cells the tyrosine kinase enzyme will induce a lot of phosphorylation of this drug which will interfere with DNA polymerase so that the tumor cells cannot reproduce anymore and are killed.

Category: Pharmacology Notes