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1. Presented by: Khadga Raj Aran
M.Pharm(Pharmacology)
Isf college of pharmacy
Moga, Punjab.

2. contents
 Introduction
 Types of Gene Therapy
 Approaches in Gene Therapy
 Vectors used in Gene Therapy
 Method of Gene Delivery
 Advantages
 Disadvantages
 Application of Gene therapy
 conclusion

3. INTRODUCTION
 Gene therapy is an experimental technique in
which introduction of normal genes into cells
in place of missing or defective ones in order
to correct genetic disorders.
 It is a technique for correcting defective
genes responsible for disease development.
 The first approved gene therapy experiment
occurred on September 14, 1990 in US, when
Ashanti DeSilva was treated for ADA-SCID.

4. TYPES OF GENE THERAPY
 Therapeutic genes
transferred into
the somatic cells.
 Eg. Introduction of genes
into bone marrow cells,
blood cells, skin cells etc.
 Will not be inherited
later generations.
 At present all researches
directed to correct genetic
defects in somatic cells.
 Therapeutic genes
transferred into the germ
cells.
 Eg. Genes introduced into
eggs and sperms.
 It is heritable and passed
on to later generations.
 For safety, ethical and
technical reasons, it is not
being attempted at
present.
• Somatic cell gene therapy • Germ line gene therapy

5. Ex vivo gene therapy:- transfer
of genes to cultured cells and
reinsertion.
In vivo gene therapy:- direct
delivery of genes into the
cells of a particular tissue in
the body
APPROACHES IN GENE THERAPY

7. EX VIVO GENE THERAPY
Transplant the modified cells to the patient.
Select genetically corrected cells and grow.
Introduce the therapeutic genes .
Grow the cells in culture
Isolate cells with genetic defect from a patient

8. EXAMPLE OF EX VIVO GENE
THERAPY
 1st gene therapy – to correct deficiency of enzyme, Adenosine
deaminase (ADA).
 Performed on a 4yr old girl Ashanthi DeSilva.
 Was suffering from SCID- Severe Combined Immunodeficiency.
 Caused due to defect in gene coding for ADA.
 Deoxy adenosine accumulate and destroys T lymphocytes.
 Disrupts immunity , suffer from infectious diseases and die at young
age.

9. IN VIVO GENE THERAPY
 Direct delivery of therapeutic gene into target cell into patients
body.
 Carried out by viral or non viral vector
systems.
 It can be the only possible option in
patients where individual cells
cannot be cultured in vitro in
sufficient numbers (e.g. brain cells).
 In vivo gene transfer is necessary when cultured cells cannot be
re-implanted in patients effectively.

10. EXAMPLE OF IN VIVO GENE THERAPY
 In patients with cystic fibrosis, a protein call cystic
fibrosis transmembrane regulator (CFTR) is absent
due to a gene defect.
 In the absence of CFTR chloride ions concentrate within
the cells and it draws water from surrounding.
 This leads to the accumulation of sticky mucous in
respiratory tract and lungs.
 Treated by in vivo replacement of defective gene by
adenovirus vector .

11. VECTORS IN GENE THERAPY
 To transfer the desired gene into a target cell , a carrier is
required such vehicles of gene delivery are known as
vectors.
2 main classes
 Viral vectors
 Non viral vectors
 Viral vectors
 1) retrovirus vectors system: Can carry a DNA of
size – less than 3.4kb

12. Conti……
 Retroviruses used in gene therapy so that any genes that are
harmful to man are removed. Corrective genes are then
added to replace the removed genes, and the new, modified
retrovirus is then introduced into the patient.
Adeno virus vector system
Gene therapy using an Adenovirus vector. A new gene is
inserted into an adenovirus vector, which is used introduce
the modified DNA into a human cell.If the treatment is
successful,the new gene will make a functional protein.
Lentivirus : It is a retrovirus it has a single stranded
RNA genome .used in haemophilia A , Rheumatoid
arthritis , Diabetes mellitus.

13. NON VIRAL VECTORS
1) pure DNA construct
Direct introduction of pure DNA construct into target tissue .
Therapeutic DNA is then made to combine with the conjugate to form a
complex.
It avoids lysosomal breakdown of DNA.
2) Lipoplexes
 Lipid DNA complexes; DNA construct surrounded by artificial
lipid layer.
 Most of it gets degraded by lysosomes

14. Gene Gun
 Employs a high-pressure delivery system to
shoot tissue with gold or tungsten particles that
are coated with DNA
Microinjection
 Process of using a glass micropipette to insert
microscopic substances into a single living cell.
 Normally performed under a specialized optical
microscope setup called a micromanipulator.
METHODS OF GENE DELIVERY
PHYSICAL METHODS

15. Conti…
Sonaporation
Using ultrasonic frequency to deliver DNA into cell.
Allows disrupt cell membrane and DNA move into
cell.
Eletroporation
Method that uses short pulses of high voltage to carry
DNA across cell membrane. Thus cause temperature
formation of pore in cell membrane allows gene to
pass through.

16. CHEMICAL METHODS
 USING DETERGENT MIXTURES
 Certain charged chemical compounds like Calcium phosphates are
mixed with functional cDNA of desired function.
 The mixture is introduced near the vicinity of recipient cells.
 The chemicals disturbs the cell membrane, widens the pore size and
allows cDNA to pass through the cell.
 LIPOFECTION
 It is a technique used to inject genetic materials into a cell by means of
liposomes.
 Liposomes are artificial phospholipid vesicles used to deliver a
variety of molecules including DNA into the cells.

17. OTHER TYPES OF GENE THERAPY
GENE AUGMENTATION THERAPY
 Most common form of gene therapy
Foreign gene replaces missing or defective gene.
Eg. Replacement of defective gene p53 by a normal one in
liver cancer.
.

18. GENE INHIBITION THERAPY
 Done to block the overproduction of some proteins.
2 types – Antigene and antisense therapy.
 Antigene – blocks transcription using antigene oligonucleotide
 Antisense – blocks transalation using antisense oligonucleotide

19. IS GENE THERAPY SAFE?
 Gene therapy is under study to determine whether it could
be used to treat disease.
 Several studies have already shown that this approach can
have very serious health risks, such as toxicity,
inflammation, and cancer.
 some of the risks may be unpredictable; however, medical
researchers, institutions, and regulatory agencies are
working to ensure that gene therapy research is as safe as
possible.
 The U.S. Food and Drug Administration (FDA) regulates all
gene therapy products in the United States and oversees
research in this area.

20. ADVANTAGES
 Gene therapy has the potential to eliminate and prevent
hereditary diseases such as cystic fibrosis, ADA- SCID etc.
 It is a possible cure for heart disease, AIDS and cancer.
 It gives someone born with a genetic disease a chance to
life.
 It can be used to eradicate diseases from the future
generations.

21. DISADVATAGES
 Long lasting therapy is not achieved by gene therapy; Due
to rapid dividing of cells benefits of gene therapy is short
lived.
 Immune response to the transferred gene stimulates a
potential risk to gene therapy.
 Viruses used as vectors for gene transfer may cause
toxicity, immune responses, and inflammatory reactions in
the host.
 Disorders caused by defects in multiple genes cannot be
treated effectively using gene therapy.

22. APPLICATION OF GENE THERAPY
 Gene Therapy Reduces parkinson’s disease symptoms
 It significantly improved the weakness of the symptoms such as tremors motor
skill problem and rigidity
 Main overactive brain region :the subthalamic nucleus should be introduced
with GAD gene
 That would produce GABA Neurotransmitters. It is an inhibitor chemical then
they could potentially quiet . that brain region and alleviate tremors
 Cystic fibrosis
 Cystic fibrosis affects the epithelial cells of the body, but the life threatening
problems mainly affect the lungs
CF is caused by a mutation in the gene cystic fibrosis transmembrane
coductance regulator.CFTR gene found in chromosome 7. product f this gene
is CFTR protein .
The aim is to get the gene into the cells so that it can make the normal protein,
i.e. CFTR

23. Contd..
 In Cancer
 Multiple gene therapy have been developed to treat a wide variety of cancers
including suicide gene therapy, anti-angiogenesis and therapeutic gene
vaccines.
 Gene therapy against cancer include the introduction of tumor suppressor
genes, gene that induces apoptosis or gene inhibitor tumor angiogenesis.
 Hemophilia
 For purpose with hemophilia therapies could be designed to deliver genes that
express missing factor viii and ix meaning individual would no longer need to
injected exogenous clotting factors
 Fat metabolism disorder
 In 2012 glybera became the first viral gene-therapy treatment to be approved in
Europe. Treatment uses in cure lipoprotein lipase deficiency.

24. Recent advances in Gene therapy
 In march 2017 French scientists reported on clinical
research of gene therapy to treat sickle-cell disease.
 In August 2017 , the FDA approved tisagenlecleucel for
acute lymphoblastic leukemia.
 Tisagenlecleucel is an adoptive cell transfer therapy for B-
cell acute lymphoblastic leukemia.
 T cells from a person with cancer are removed, genetically
engineered to make a specific T-cell receptor that reacts to
the cancer, and are administered back to the person.

25. Conti …
 This is the first form of gene therapy to be approved in
the United States. In October, a similar therapy
called axicabtagene ciloleucel was approved
for lymphoma.
 In a new gene therapy method developed by University
of Florida researchers found treatment for a
common form of blindness that strikes both
youngsters and adults.

26. CONCLUSION
 Theoretically, gene therapy is the permanent solution for
genetic diseases.
 But it has several complexities. At its current stage, it is not
accessible to most people due to its huge cost.
 A breakthrough may come anytime and a day may come
when almost every disease will have a gene therapy
 Gene therapy have the potential to revolutionize the
practice of medicine.

27. REFERENCES
 Dubey R.C, A textbook of biotechnology, 1st edition(2004), S
Chand and company, New Delhi
 Gupta P.K, Elements of Biotechnology, 1st edition(2001), Rastogi
Publications, Meerut.
 Satyanarayana U, Biotechnology, 1st edition, Book and allied (P)
Ltd, Kolkata.
 http://www.medindia.net/articles/genetherapy_treatment.htm
 http://en.wikipedia.org/wiki/Gene_therapy

28. Thanks for your patience