Topic: Gene therapy

Target group

High school / technical school student

Core curriculum

General requirements

V. Reasoning and applying the acquired knowledge to solving biological problems. Students:

1. interpret information and explain causal relationships between processes and phenomena, formulate conclusions.

Specific requirements

XV. Biotechnology. Basics of genetic engineering. Student:

12. explains the essence of gene therapy.

General aim of education

Students explain what gene therapy is all about.

Key competences

• communication in foreign languages;

• digital competence;

• learning to learn.

Criteria for success
The student will learn:

• assess the usefulness of gene therapy in medicine;

• present examples of the use of gene therapy;

• identify the risks resulting from the use of gene therapy;

• present the advantages and disadvantages of using gene therapy in humans.

Methods/techniques

• expository

  • talk.

• activating

  • discussion.

• programmed

  • with computer;

  • with e‑textbook.

• practical

  • exercices concerned.

Forms of work

• individual activity;

• activity in pairs;

• activity in groups;

• collective activity.

Teaching aids

• e‑textbook;

• notebook and crayons/felt‑tip pens;

• interactive whiteboard, tablets/computers.

Lesson plan overview

Before classes

• Students get acquainted with the content of the abstract. They prepare to work on the lesson in such a way to be able to summarize the material read in their own words and solve the tasks themselves.

Introduction

• The teacher gives the topic, the goals of the lesson in a language understandable for the student, and the criteria of success.

• The instructor asks one student to briefly discuss what the genes are, then asks the class what they associate with the word „therapy”..

Realization

• The participants will familiarize themselves with the content presented in the interactive illustration „Gene therapy.” Next, the teacher discusses the issues discussed with the students. The lecturer introduces the idea of gene therapy and discusses the techniques of its application.

• The teacher divides the class into followers and opponents of gene therapy as well as people who have a neutral attitude towards this method of treatment. Students work in groups: supporters search in abstract and in other available sources information about cases of successful gene therapy, opponents - information on the failures of this method of treatment, and people with a neutral mind - facts about the techniques of introducing therapeutic genes into the body with the help of selected vectors.

• Supporters and opponents of gene therapy, in turn, give arguments in support of their position, describing cases of gene therapy ended with success or failure. Then people with a neutral sentence try to explain the reasons for treatment failures based on the information they analyzed regarding the techniques of introducing therapeutic genes into the body. The class, in conducting the discussion, tries to work out a compromise and identify those threats which scientists dealing with gene therapy should seek to remove..

• The teacher asks students to carry out the recommended interactive exercise themselves.

Summary

• The teacher briefly presents the most important issues discussed in class. He answers the additional questions of the proteges and explains all their doubts. Students complete notes.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Gene therapy

The term „gene therapy” was introduced in 1962 by Wacław Szybalski. He was one of the first scientists who genetically modified eukaryotic cells. He managed to insert a piece of normal human DNA instead of mutant genes in bone marrow cells. The wrong DNA strand was repaired for the first time this way, laying foundations for other treatments and methods of the gene therapy.

The gene therapy is a method of treating genetic diseases by introducing a correct copy of a gene, whose defect causes a disease, into cells. The purpose of the therapy may also be to turn on or off the function of a specific gene or to introduce an additional therapeutic gene.

Vectors, i.e. gene carriers, are used to introduce genetic material into cells of a body undergoing the therapy. The most popular ones are viral vectors. Modified viral particles, which can introduce DNA encoding, for example, therapeutic proteins, are used for therapeutic purposes. These viruses cannot infect the body, because they have been deprived of genes dangerous to humans as a result of genetic transformations.

Non‑viral vectors may also be used in the gene therapy. A liposome is a spherical vesicle that contains nucleic acid fragments or otherwise DNA. Viral proteins or other substances, which allow for cell penetration, are often added to them. When such a complex enters cytoplasm, DNA separates from a liposome. Introduced this way, nucleic acid enables the production of desired substances.

The gene therapy may involve reproductive cells, from which a new organism is to be formed, or embryo‑forming cells. If applied to the embryo, it enables an introduced change to be inherited. If applied to somatic cells, which build up the body, no changes are inherited. This treatment is conservative, as only symptoms, not the cause of the disease, are treated. At present, the somatic therapy in the only one used in patients. The reproductive cell therapy is prohibited due to ethical aspects.

So far, the gene therapy was attempted to be used to treat:

• cancers;

• diseases caused by monogenic dominant mutations, such as Huntington's chorea;

• diseases caused by monogenic recessive mutations, such as sickle cell anemia, cystic fibrosis, haemophilia;

• congenital blindness, i.e. an autosomal recessive disease, caused by a mutation in a gene encoding protein necessary for vision.

One disease, which can be treated with the gene therapy, is a severe immunodeficiency caused by a gene mutation (SCID syndrome). In this case, a patient's body lacks an enzyme necessary for the proper functioning of lymphocytes. The disease is manifested by low weight gain, low growth, frequent and recurrent infections, e.g. pneumonia, sepsis. If untreated, it leads to death which usually occurs before the age of 2.

There is also ongoing research on the treatment of diabetes.

The introduction of foreign DNA molecules to the human body raises many fears. Despite numerous attempts of treatment (cancers, phenylketonuria, dwarfism, insulin‑dependent diabetes) and very promising results, the use of gene therapy is in some cases risky and even dangerous due to its side effects. The gene therapy is an experimental therapy at present, thus it cannot be used widely. So far, it has led to two deaths – a boy with immunity disorders and a teenager suffering from a rare liver disease. The latter died probably due to a violent immune response.

The use of viruses in the human gene therapy carries some risk, although genes dangerous to humans are removed. First of all, viral DNA is short, so it cannot contain many genes. It should be remembered that viral genetic material easily mutates, therefore any modified virus can become dangerous again. There is also no way of controlling where therapeutic genes are embedded which in turn makes the therapy less efficient. A badly embedded gene can also create an incorrect sequence – a new genetic defect.

• The gene therapy is an experimental field of science.

• The gene therapy can be used to treat genetic diseases, cancers and infectious diseases.