In vivo DNA transfection?

Question

Every time I hear about transfection, it refers to in vitro transfection. Is there any way to transfect DNA into cells in a living organism?

Answer 1

I think in vivo DNA transfection would be one of the "holy grails" of disease research...think of all the genetic diseases that could be cured by injecting the DNA encoding the missing gene into your patient!!! People are working on it, but it's pretty difficult--the hard part is "convincing" your cell (complete with it's own DNA) to 1) take up this foreign DNA 2) once it's inside the cell, that the cell doesn't destroy the DNA 3) if the DNA is not destroyed, it gets incorporated into the cell's own DNA (in the right place, so as not to mess up any other genes!) so that when the cell divides, the injected gene will be passed onto the progeny cells.

Some of the ways that I've heard being tested for in-vivo transfections include using liposomes and using viral vectors.
But as far as I know, no method has been a smashing success yet (in terms of DNA transfection--liposomes have been used successfully in the clinic for delivery of chemotherapeutic drugs, etc).

Also, there has been some success in cancer research using autologous cell transfections--for example, take dendritic cells out of a patient and transfect them with DNA encoding GM-CSF or B7 (puts dendritic cell into activated state) and culture the dendritic cells with a solution of tumor cell extract (so that the dendritic cells can pick up tumor specific antigens), then inject these transfected cells back into the patient. By doing this, you can make the patient's immune system recognize and attack some kinds of tumors. This approach seems to work particularly for melanomas. The transfection process is still an in-vitro one, but then the cells are used in-vivo. Since you have to do this for each individual patient (take out each patient's dendritic cells and some of their tumor cells), it is a laborious and very expensive process. So I really hope some new methods of in-vivo transfection become a reality very soon!!!

Answer 2

The most we ever do along those lines is microinjection of DNA into oocytes. This allows the DNA to be (hopefully) incorporated into the genome of the embryo. Otherwise, the main method is retrovirus-mediated DNA introduction into young or adult organisms, which is a bit 'iffy'.

Answer 3

Depends on cell line, I recommend liposome transfection.
It's easy, high transfection efficacy and cell viability.

I often use Lipofectamine2000
https://catalog.invitrogen.com/index.cfm?fuseaction=viewCatalog.viewProductDetails&productDescription=541&

Answer 4

Yes, but because living cells already have their own DNA, you would have to interrupt transcription by termination before you could transfer the DNA.