In most gene therapy studies, a "normal" gene is inserted into the genome to replace an "abnormal," disease-causing gene. In cancer, some cells become diseased because certain genes have been permanently turned off. Using gene therapy, mutated genes that cause disease could be turned off so that they no longer promote disease, or healthy genes that help prevent disease could be turned on so that they can inhibit the disease.

Other cells may be missing certain genes. Researchers hope that replacing missing or defective genes can help treat certain diseases. For example, a common tumor suppressor gene called p53 normally prevents tumor growth in your body. Several types of cancer have been linked to a missing or inactive p53 gene. If doctors could replace p53 where it's missing, that might trigger the cancer cells to die.

How are the genes delivered into cells?

A carrier molecule called a vector must be used to deliver the therapeutic gene to the patient's target cells.

1. Viruses

The most common gene therapy vectors are viruses because they can recognize certain cells and carry genetic material into the cells' genes. Researchers are trying to take advantage of this unique capability. They:

Some of the different types of viruses used as gene therapy vectors:

• Retroviruses - A class of viruses that can create double-stranded DNA copies of their RNA genomes. These copies of its genome can be integrated into the chromosomes of host cells. Human immunodeficiency virus (HIV) is a retrovirus.
• Adenoviruses - A class of viruses with double-stranded DNA genomes that cause respiratory, intestinal, and eye infections in humans. The virus that causes the common cold is an adenovirus.
• Adeno-associated viruses (AAV) - These are small DNA viruses that integrate successfully in one spot of the host's genome (on chromosome 19 in humans). They can't replicate by themselves and therefore require a helper virus, either adenovirus or herpes virus. Also they are non-pathogenic (not known to cause disease).
• Herpes simplex viruses - A class of double-stranded DNA viruses that infect a particular cell type, neurons. Herpes simplex virus type 1 is a common human pathogen that causes cold sores.

2. Stem cells

Stem cells create all other cells with specialized functions in the body. In gene therapy, stem cells can be altered in a laboratory to accept new genes that can help fight disease.

3. Liposomes

These fatty particles are nanoscale devices that have the ability to carry the new, therapeutic genes to the target cells and pass the genes into the cells' DNA. Liposomes were developed with nanotechnology.

The current focus in the field of gene therapy is on development of genetic drugs that are capable of treating diseases such as cancer and inflammation. This is an image of genetic materials encapsulated into a liposome.

Using the Immune System

In some cases, the immune system does not attack diseased cells because it does not recognize them as intruders or non-self. Using gene therapy, physicians could potentially infuse tumor cells with genes that make them more recognizable to your immune system. Enhancements could also be made to immune cells to make it easier for them to recognize mutated tumor cells.

regards

Thanks!

Thanks for notification Artur.

Sahand

Dear Artur,

Thank you indeed!

Dear Artur,

Please see this.

Article BDI-modelling of complex intracellular dynamics

It seems gene therapy works!

What I got from this fascinating book chapter:

'Gene Therapy In: Bio-Orthopedics: A New Approach'

"

Gene therapy;

1- in vivo (direct gene delivery into cells within the fracture site)

2- ex-vivo (indirect gene delivery, e.g., via stem cells or fibroblasts, following extracorporeal in vitro transfection or transduction)

Gene therapy vectors;

1. Nonviral gene transfer systems

2. Adnoviral vectors

3.Retro-/Lentiviral vectors

4.Herpes simplex virus vectors

5. Adeno-associated viral (AAV) vectors

"

But as I read, for some of these ways there is not any evidence of being harmful.

As I understood, maybe I am wrong.

It is really an interesting area to investigate, indeed! Thanks for sharing opinion and knowledge.

I hope too!

Hi.

here are some review paper you may find interesting:

Prud’homme GJ, Glinka Y, Khan AS, Draghia-Akli R (2006) Electroporation enhanced nonviral gene transfer for the prevention or treatment of immunological, endocrine and neoplastic diseases. Current Gene Therapy 6:243-273

Heller LC, Heller R (2010) Electroporation gene therapy preclinical and clinical trials for melanoma. Current Gene Therapy 10: 312-317

Cemazar M, Jarm T, Sersa G (2010) Cancer electrogene therapy with Inteleukin-12. Current Gene Therapy 10: 300-311

Chabot S, Pelofy S, Paganin-Gioanni A, Teissie J, Golzio M (2011) Electrotransfer of RNAi-based oligonucleotides for oncology. Anticancer Research 31: 4083-4090

Kesmodel SB, Spitz FR (2003) Gene therapy for cancer and metastatic dissease. Expert reviews in molecular reviews 5: June, DOI: 10.1017/S1462399403006380

Palmer DH, Young LS, Mautner V (2006) Cancer gene-therapy: Clinical trials. Trends in Biotechnology 24: 76-82

Thank you Niloufar!