Gene Therapy

Gene Therapy is hope or disaster

for Human Being?

Changhwan Hong

Biology Project

Biology Acc Mrs.T

4/11/2005

◊Introduction

DNA determines the placement of amino acids according to DNA sequences. A specific chain of amino acids composes a specific protein that plays the essential functions in the bodies. The defect of the gene, however, results in producing wrong protein; as a result, some part of the bodies abnormally works compared to that of other normal bodies. This is called ЃgGenetic DisorderЃh. The scientists studied about genetic disorder and suggested an alternative for genetic disorder called ЃgGene TherapyЃh. Recently, gene therapy is useful to cure other diseases such as a cancer or other.

(http://www.ornl.gov/sci/techresources/Human_Genome/medicine/genetherapy.shtml

http://www.asgt.org/ )

◊History of Gene Therapy

David suffered from a rare inherited disease known as adenosine deaminase deficiency (ADA). He spent all his life in a germ-free plastic bubble, because gene causes a lack of enzyme that helps immune system to fight disease from outside. In 1984, he received a bone marrow transplant. Unfortunately, cells from donatorЃfs marrow attacked his body. As a result, he was died after a year. This event was a big issue at that time and scientists studied gene therapy to stop this bad event. In 1989, at first, W.French Anderson and a team at the National Institutes of Health gained permission for experiment to inject gene into human beings. In 1900, at first, he applied gene therapy to 4 year girl who suffered from adenosine deaminase deficiency (ADA). He extracted T- lymphocytes from her bloodstream and injected gene-corrected T lymphocytes to her with a normal gene function for ADA; then he repeated a few times more. After a year, she lives as a normal kid. Her treatment was successful. In 1991, 9 years old girl was applied to this gene therapy and her treatment was also successful.

(http://www.frenchanderson.org/history/history.asp,

Mapping our genes by Lois Wingerson, Medical Dilemma by Margaret O.Hyde& Elizabeth H. Forsyth. M.D.)

◊Gene Therapy

Today, basic theory of gene therapy is that normal gene is inserted into genome to replace disease caused gene. The gene by itself, however, is almost impossible to get the target cell. To deliver gene successfully, a carrier called vector is necessary and virus is good for delivering gene, because virus genetically approaches human genes. Virus, however, can have a potential toxic or respond a massive immune system. In fact, some people died because of that. For this reason, scientists tried to find replacement of virus as vector. The most common virus for vector is adenovirus that causes cold.

Ѓ™Gene Therapy for Sickle Cell Anemia

Changing shape of red blood cells causes sickle cell anemia. Because the blood cell is sickle, abnormal hemoglobin called Hb S is produced; as a result, the blood cell doesnЃft carry enough O2. (In Class) This disease is possible to cure by gene therapy. Gene red blood cell with normal hemoglobin is inserted into the stem cell by packing them inside virus and this stem cell became regular red blood cell A. This stem cell is transplanted the marrow and produces enough Hb A in regular cell to prevent polymerization Hb S in sickle cell. To success this treatment, lots of stem cells are copied and then transplanted.

(Understanding sickle cell disease by Bloom, Miriam)

Ѓ™Gene therapy for Cancer (actually, cancerЃfs side effects)

The common treatment of cancer is chemotherapy or radiotherapy. This treatment, however, affects health cells badly and causes side effects such as severe nausea, hair loss, exhaustion, and reduced immunity to germs and virus etc. Gene therapy may eradicate theses side effects. Inside the cancer cell, there is a gene MDR that makes cells resistant to the radiation and chemotherapy. In the cancer, this gene, however, makes less resistant to the radiation and chemotherapy. Therefore, to treat these side effects, the MDR gene in cancer is extracted and returned corrected- gene into the body. As a result, the body is responsible to the chemotherapy and radiation and the side effects after cancer might not be caused.

From Gene Therapy Can Eliminate( Opposing Viewpoint Digests; Biomedical Ethics)

Ѓ™Suicide Genes

Suicide genes only attack the multiplying tumor cells but suicide genes donЃft reproduce in the body and infect other health part. By this method, most patient was successful to cure their diseases

From Gene Therapy Can Eliminate ( Opposing Viewpoint Digests; Biomedical Ethics)

There is another gene therapy that applied to gamete. This gene therapy prevents future disease of baby before the birth. This type of gene therapy, however, is controversial in society at present, so this gene therapy is impossible in reality.

Caskey said about this gene therapy ЃgThis area is an exiting area not applicable to manЃh(from Mapping Our