Gene therapy, the latest development in the medical field, basically tries to manipulate the genetic material, in order to treat and prevent the occurrence of certain diseases that are difficult to cure with normal treatment. It involves the insertion of genes, the biological unit of heredity, into the cells or tissues of individuals suffering from diseases like cancer.
Gene Therapy: A Boon or Bane?
This therapy was first conducted on September 14, 1990 by a group of physicians, which include W. French Anderson (M.D) and his colleagues R. Michael Blaese (M.D), C. Bouzaid and Kenneth Culver (M.D) from the U.S. National Institute of Health. It was performed on a four-year-old child suffering from 'Severe Combined Immunodeficiency', a rare genetic disease.
This therapy can be classified into two main types - germ line and somatic gene therapy. The germ line gene therapy involves the insertion of functional genes into the germ or reproductive cells (sperm and egg) of the body, while in somatic gene therapy, therapeutic genes are introduced into the somatic cells.
This therapy modifies the genetic material (DNA or gene), which plays a key role in determining the traits and characteristics of an individual. Gene therapy has added a completely new dimension to the treatment of cancer, which is caused by the mutation in the DNA leading to the uncontrolled growth of abnormal cells.
Many research and studies have been carried out, and some are still going on to discover the potential of gene therapy in treating cancers of the breast, lungs, prostate, bones, as well as leukemia. This therapy basically tries to destroy or prevent the growth of cancerous cells, or improve the ability of the normal cells to fight the cancerous cells.
If cancer is caused due to missing or altered genes, such genes are replaced with the healthy ones. This therapy can also be used to stimulate the immune system to attack the cancer cells. Through this technology, genes can be inserted into the patient's body, which can instruct the cancer cells to produce certain proteins for inhibiting the cancer-causing oncogenes, or stimulate the tumor suppressor genes.
Some other studies are going on to find out the possibility of introducing genes into the cancerous cells, which can help make them more responsive to various cancer treatments, including chemotherapy and radiation therapy. Studies are also being carried out to find out if this therapy can reduce the side effects of various anti-cancer drugs by increasing the resistance of the stem cells.
In gene therapy, genes are not directly inserted into the cells. Rather, viruses are used for that purpose. The viruses that are generally used in this therapy are, retroviruses, adenoviruses, herpes viruses, lentiviruses, and poxviruses. Sometimes, a liposome is also used as a carrier. A liposome is actually an artificially created tiny vesicle that can be used to deliver nutrients and drugs into the cells.
Viruses can be used for both the 'ex vivo' and the 'in vivo' gene therapy. In 'ex vivo' gene therapy, a sample of blood or bone marrow cells are collected from the patient. The viruses with the necessary genes are then introduced into these cells in a laboratory, which are then injected into the patient's body. On the other hand, the 'in vivo' gene therapy involves the direct insertion of the viruses or liposomes that contain the desired genetic material.
However, this therapy does have some disadvantages. One of the most potential dangers associated with this therapy, is the possibility of an infection that can be caused by the viruses used for delivering the genetic material. If the genetic material is accidentally introduced into the germ cells, then the changes induced by it would pass on to the next generation.
Again, it is important to insert the desired gene at the correct location, and a failure to do so might result in genetic mutations and cancer. Therefore, more scientific research and studies are required to address these drawbacks, so that this therapy can truly revolutionize the treatment of life-threatening diseases like cancer.