Question

Provide two examples of how therapeutic genes can be delivered into cells, and discuss the challenges scientists face in making gene therapy an effective technique for treating human genetic disease conditions.

basic biotechnology

Answer 1

Gene therapy is an experimental technique that uses genes to treat or prevent disease. This technique may allow doctors to treat a disorder by inserting a gene into a patient’s cells instead of using drugs or surgery. Researchers are testing several approaches to gene therapy, including Replacing a mutated gene that causes disease with a healthy copy of the gene.Inactivating, or “knocking out,” a mutated gene that is functioning improperly.Introducing a new gene into the body to help fight a disease.

Gene therapy is used to correct defective genes in order to cure a disease or help your body better fight disease.Replacing mutated genes. Some cells become diseased because certain genes work incorrectly or no longer work at all. Replacing the defective genes may help treat certain diseases. For instance, a gene called p53 normally prevents tumor growth. Several types of cancer have been linked to problems with the p53 gene. If doctors could replace the defective p53 gene, that might trigger the cancer cells to die.Fixing mutated genes. 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 could inhibit the disease.Making diseased cells more evident to the immune system. In some cases, your immune system doesn't attack diseased cells because it doesn't recognize them as intruders. Doctors could use gene therapy to train your immune system to recognize the cells that are a threat.Therapeutic genes can be inserted directly into the plasmid, and then this recombinant plasmid can be introduced into cells in a variety of ways. For example, it can be injected directly into targeted tissues as naked-DNA. Non-viral vectors are much cheaper and easier to produce in large amounts.

• Challenges scientists face in making gene therapy an effective technique for treating human genetic disease conditions.

Gene therapy has some potential risks. A gene can't easily be inserted directly into your cells. Rather, it usually has to be delivered using a carrier, called a vector. The most common gene therapy vectors are viruses because they can recognize certain cells and carry genetic material into the cells' genes.

1. Gene delivery and activation

For some disorders, gene therapy will work only if we can deliver a normal gene to a large number of cells—say several million—in a tissue. And they have to the correct cells, in the correct tissue. Once the gene reaches its destination, it must be activated, or turned on, to make the protein it encodes. And once it's turned on, it must remain on; cells have a habit of shutting down genes that are too active or exhibiting other unusual behaviors.

Introducing changes into the wrong cells Targeting a gene to the correct cells is crucial to the success of any gene therapy treatment. Just as important, though, is making sure that the gene is not incorporated into the wrong cells. Delivering a gene to the wrong tissue would be inefficient, and it could cause health problems for the patient.

2.Immune response

Our immune systems are very good at fighting off intruders such as bacteria and viruses. Gene-delivery vectors must be able to avoid the body's natural surveillance system. An unwelcome immune response could cause serious illness or even death.

One way researchers avoid triggering an immune response is by delivering viruses to cells outside of the patient's body. Another is to give patients drugs to temporarily suppress the immune system during treatment. Researchers use the lowest dose of virus that is effective, and whenever possible, they use vectors that are less likely to trigger an immune response.

3.Disrupting important genes in target cells

A good gene therapy is one that will last. Ideally, an introduced gene will continue working for the rest of the patient's life. For this to happen, the introduced gene must become a permanent part of the target cell's genome, usually by integrating, or "stitching" itself, into the cell's own DNA. To escape infections and illness, they must live in a completely germ-free environment.Some newer vectors have features that target DNA integration to specific "safe" places in the genome where it won't cause problems. And genes introduced to cells outside of the patient can be tested to see where they integrated, before they are returned to the patient.

4 Commercial viability

Many genetic disorders that can potentially be treated with gene therapy are extremely rare, some affecting just one person out of a million. Gene therapy could be life-saving for these patients, but the high cost of developing a treatment makes it an unappealing prospect for pharmaceutical companies.

Developing a new therapy including taking it through the clinical trials necessary for government approval— is very expensive. With a limited number of patients to recover those expenses from, developers may never earn money from treating such rare genetic disorders. And some patients may never be able to afford them.

Some diseases that can be treated with gene therapy, such as cancer, are much more common. However, many promising gene therapy approaches are individualized to each patient. For example, a patient's own cells may be taken out, modified with a therapeutic gene, and returned to the patient. This individualized approach may prove to be very effective, but it's also costly. It comes at a much higher price than drugs that can be manufactured in bulk, which can quickly recover the cost of their development.

Working towards an ideal label

Securing the supply chain

Comforting the challenges of reimbursement

Understanding the patients journey are the other challenges of gene therapy