Gene Therapy - technologies, markets and companies

0. Executive Summary ............... 18

1. Introduction . 20

Definitions ............. 20

Historical evolution of gene therapy .................. 20

Relation of gene therapy to other biotechnologies................ 22

Molecular biological basics for gene therapy...... 22

Genome..............22

DNA .23

RNA.23

Alternative RNA splicing .......24

Genes.................25

Gene regulation ....25

Gene expression ...27

Chromosomes.......27

Telomeres ............28

Mitochondrial DNA.28

Proteins ...............29

2. Gene Therapy Technologies ... 30

Classification of gene therapy techniques.......... 30

Ex vivo and in vivo gene therapy..... 31

Ex vivo gene therapy................31

In vivo gene therapy ................32

Physical methods of gene transfer.. 32

Electroporation .....32

Applications of electroporation ...33

Clinical applications of electroporation ............34

Advantages of electroporation.....34

Limitations of electroporation35

Hydrodynamic ......35

Microinjection .......35

Particle bombardment...............36

Ultrasound-mediated transfection.....38

Molecular vibration 39

Application of pulsed magnetic field and superparamagnetic nanoparticles ...........39

Gene transfection using laser irradiation ..............39

Photochemical transfection........40

Chemical methods of gene transfer. 40

Gene repair and replacement.... 40

Gene repair by single-stranded oligonucleotides....41

History and current status of chimeraplasty..........41

Spliceosome-mediated RNA trans-splicing......... 41

mRNA gene therapy .................. 42

Vectors for gene therapy........... 42

Basic considerations .................42

Use of genes as pharmaceuticals43

The ideal vector for gene therapy.....43

Viral vectors .........44

Retroviral vectors................44

Oncognic potential of retroviral vectors ...........46

Adenovirus vectors..............47

Adeno-associated virus vectors ...49

Herpes simplex virus vectors 51

Lentiviral vectors.................53

Baculovirus vectors .............54

Alphavirus vectors...............54

Multicistronic retroviral vectors ...55

Companies using viral vectors.....55

Non-viral vectors for gene therapy ...57

Liposomes for gene therapy..58

Cationic lipid-DNA complexes59

Anionic lipid-DNA complexes.60

HVJ-liposome method ..........60

Polycation-DNA complexes (polyplexes) ..........61

Synthetic peptide complexes 61

Polymer molecules ..............62

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Nanobiotechnology for gene transfer 62

Nanoparticles as non-viral vectors for gene therapy.............62

Dendrimers .....63

Cochleates ......63

Calcium phosphate nanoparticles as non-viral vectors..........64

Lipid nanoparticles for nucleic acid delivery .....64

Silica nanoparticles as a nonviral vector for gene delivery ....65

Gelatin nanoparticles for gene delivery ...........65

Nonionic polymeric micelles for oral gene delivery ...............65

Biological nanoparticle technology ..................66

Receptor-mediated endocytosis .66

Artificial viral vectors ................67

Directed evolution of AAV to create efficient gene delivery vectors ...68

Bacterial ghosts as DNA delivery systems.............68

Bacteria plus nanoparticles for gene delivery into cells..............68

Chromosome-based vectors for gene therapy .......69

Companies using non-viral vectors ...71

Concluding remarks about vectors....72

Cell-mediated gene therapy ...... 73

Fibroblasts ...........74

Skeletal muscle cells.................74

Vascular smooth muscle cells ....75

Keratinocytes .......75

Hepatocytes .........75

Lymphocytes ........76

Regulating protein delivery by genetically encoded lymphocytes .76

Implantation of microencapulated genetically modified cells ......76

Stem cell gene therapy .............77

Therapeutic applications for hematopoietic stem cell gene transfer .................77

Improving delivery of genes to stem cells........78

Lentiviral vectors for gene transfer to marrow stem cells......78

Use of mesenchymal stem cells for gene therapy ................78

In utero gene therapy using stem cells ...........78

Gene delivery to stem cells by artificial chromosome expression .79

Linker based sperm-mediated gene transfer technology.......79

Combination of gene therapy with therapeutic cloning .........79

Expansion of transduced HSCs in vivo.............80

The future of hematopoietic stem cell gene therapy.............80

Routes of administration for gene therapy......... 80

Direct injection of naked DNA ....81

Intramuscular injection .............81

Intravenous DNA injection.........81

Intraarterial delivery.................81

Companies with gene delivery devices/ technologies ................82

Targeted gene therapy.............. 83

Targeted integration .................83

Bacteriophage integrase system for site-specific gene delivery...84

Controlled-release delivery of DNA ...84

Controlled gene therapy............ 85

Controlled delivery of genetic material .................85

Controlled induction of gene expression ...............85

Drug-inducible systems for control of gene expression..............86

Timed activation of gene therapy by a circuit based on signaling network............86

Small molecules for post-transcriptional regulation of gene expression ................86

Light Activated Gene Therapy ....87

Engineered zinc finger DNA binding proteins for gene correction 87

Companies with regulated /targeted gene therapy.87

Gene marking......... 89

Germline gene therapy.............. 89

Potential applications of human germline genome modification ..89

Pros and cons of human germline genome modification ............90

Role of gene transfer in antibody therapy.......... 91

Genetically engineered vaccines ..... 91

DNA vaccines........91

DNA inoculation technology ..92

Methods for enhancing the potency of DNA vaccines............92

Advantages of DNA vaccines.93

Vaccine vectors.....93

Challenges and limitations of genetically engineered vaccines....94

Vaccines based on reverse genetics..95

Technologies for gene suppression . 95

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Antisense oligonucleotides.........95

Transcription factor decoys........96

Aptamers .............96

Ribozymes ...........97

Peptide nucleic acid ..................97

Intracellular delivery of PNAs 97

Locked nucleic acid98

Zorro-LNA .......98

Gene silencing ......98

Post-transcriptional gene silencing ...98

Definitions and terminology of RNAi..99

RNAi mechanisms .99

Inhibition of gene expression by antigene RNA.... 100

RNAi gene therapy ................. 100

Application of molecular diagnostic methods in gene therapy .. 101

Use of PCR to study biodistribution of gene therapy vector ...... 101

PCR for verification of the transcription of DNA ... 101

In situ PCR for direct quantification of gene transfer into cells.. 101

Detection of retroviruses by reverse transcriptase (RT)-PCR.... 102

Confirmation of viral vector integration .............. 102

Monitoring of gene expression . 102

Monitoring of gene expression by green fluorescent protein 102

Monitoring in vivo gene expression by molecular imaging... 103

Advantages of gene therapy compared with protein therapy ..... 103

3. Clinical Applications of Gene Therapy ..... 105

Introduction........ 105

Bone and joint disorders ......... 105

Bone fractures .... 105

Gene therapy for intervertebral disc degeneration .................. 106

Spinal fusion....... 106

Osteogenesis imperfecta ......... 107

Rheumatoid arthritis............... 107

Local or systemic treatment 108

In vivo or ex vivo gene therapy of RA ........... 108

Clinical trials.. 109

Gene therapy for osteoarthritis  110

Sports injuries .... 111

Repair of articular cartilage defects............... 111

Regeneration and replacement of bone by gene therapy ......... 112

Dentistry............. 113

Tissue engineering in dental implant defects....... 113

Endocrine disorders ................ 113

Introduction ....... 113

Diabetes mellitus  113

Methods of gene therapy of diabetes mellitus ..... 114

Viral vector-mediated gene transfer in diabetes ................ 115

Gene delivery with ultrasonic microbubble destruction technology ................ 115

Genetically engineered cells for diabetes mellitus .............. 116

Genetically altered liver cells .... 116

Genetically modified stem cells . 116

Genetically engineered dendritic cells ........... 117

Insertion of gene encoding for IL-4............... 117

Concluding remarks about cell and gene therapy of diabetes .... 117

Gene therapy of growth-hormone deficiency....... 118

Gene therapy of obesity.......... 119

Ad viral vector-mediated transfer of leptin gene................ 119

AAV vector-mediated delivery of GDNF for obesity ............ 119

Gastrointestinal disorders....... 120

Introduction ....... 120

Methods of gene transfer to the gastrointestinal tract ............. 120

Direct delivery of genes ..... 120

Naked plasmid DNA into the submucosa........ 120

Viral vectors .. 121

Receptor-mediated endocytosis. 121

Indications for gastrointestinal gene therapy ...... 121

Gene therapy for inflammatory disorders of the bowel ....... 122

Gene transfer to the salivary glands .................. 122

Potential clinical applications of salivary gene therapy........ 123

Hematology.......... 123

Hemophilias ....... 124

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Gene therapy of hemophilia 124

Hemophilia A . 125

Hemophilia B . 125

Concluding remarks about gene therapy of hemophilias ..... 126

Hemoglobinopathies ............... 126

Gene therapy for b-thalassemia  128

Gene therapy of Fanconi's anemia ................ 129

Acquired hematopoietic disorders... 129

Chronic acquired anemias .. 129

Neutropenia .. 130

Thrombocytopenia............. 131

Concluding remarks about gene therapy of hemoglobinopathies..... 131

Companies involved in gene thery of hematological disorders .. 132

In utero gene therapy............. 132

Fetal gene transfer techniques . 132

Animal models of fetal gene therapy.................. 133

Potential applications of fetal gene therapy......... 134

Fetal gene therapy for cystic fibrosis............. 134

Fetal intestinal gene therapy..... 134

Hearing disorders  135

Potential of gene therapy ........ 135

Vectors for gene therapy of hearing disorders..... 135

Auditory hair cell replacement and hearing improvement by gene therapy ......... 136

Kidney diseases ... 136

End-stage renal disease .......... 136

Methods of gene delivery to the kidney .............. 137

Gene transfer into kidney by adenoviral vectors................ 138

Non-viral gene transfer to the kidneys .......... 138

Gene transfer into the glomerulus by HVJ-liposome ........... 138

Bone marrow stem cells for renal disease...... 138

Mesangial cell therapy ....... 138

Liposome-mediated gene transfer into the tubules ............ 139

Gene transfer to tubules with cationic polymer polyethylenimine.................. 139

Gene therapy in animal experimental models of renal disease.. 140

Genetic manipulations of the embryonic kidney... 140

Antisense intervention in glomerulonephritis....... 140

Gene therapy for renal fibrosis. 141

Use of genetically engineered cells for uremia due to renal failure .. 141

Concluding remarks................ 141

Liver disorders ..... 142

Techniques of gene delivery to liver 142

Direct injection of DNA into liver .................. 143

Local gene delivery by isolated organ perfusion................. 143

Liposome-mediated direct gene transfer ....... 143

Retroviral vector for gene transfer to liver ..... 143

Adenoviral vectors for gene transfer to liver .. 144

Receptor-mediated approach .... 144

Cell therapy for liver disorders . 144

Transplantation of genetically modified hepatocytes .......... 145

Genetically modified hematopoietic stem cells 145

Gene therapy by ex vivo transduced liver progenitor cells .. 145

Gene therapy of genetic diseases affecting the liver................ 145

Crigler-Najjar syndrome..... 146

Hereditary tyrosinemia type I (HT1) ............. 146

Hereditary tyrosinemia type 3... 146

Gene therapy of acquired diseases affecting the liver.............. 146

Cirrhosis of liver................ 147

Ophthalmic disorders.............. 147

Introduction to gene therapy of ophthalmic disorders ............. 147

Degenerative retinal disorders . 148

Inherited retinal degenerations . 148

Leber's congenital amaurosis .... 148

X-linked juvenile retinoschisis ... 149

Retinitis pigmentosa .......... 149

Age-related macular degeneration................ 150

Proliferative retinopathies........ 151

Methods of gene transfer to retinal cells............. 151

DNA nanoparticles for nonviral gene transfer to the eye ..... 153

Prevention of complications associated with eye surgery ......... 153

Prevention of proliferative retinopathy by gene therapy ..... 153

DNA nanoparticles for gene therapy of retinal degenerative disorders ........... 153

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Posterior capsule opacification after cataract surgery......... 153

Autoimmune uveitis................ 154

Retinal ischemic injury............ 154

Corneal disorders  155

Glaucoma........... 155

Disorders of hearing ............... 156

Gene therapy for hearing loss.. 156

Organ transplantation............. 156

Introduction ....... 156

Gene therapy for prolonging allograft survival..... 157

Gene therapy in lung transplantation ................. 157

Role of gene therapy in liver transplantation....... 157

Gene therapy in kidney transplantation.............. 158

Pulmonary disorders............... 158

Techniques of gene delivery to the lungs............ 158

Adenoviral vectors............. 159

Non-viral vectors............... 160

Aerosolization as an aid to gene transfer to lungs.............. 160

Cystic fibrosis ..... 160

Genetics and clinical features.... 160

Gene therapy for CF .......... 161

CFTR gene transfer in CF.... 161

Concluding remarks about gene therapy of CF .................. 162

Miscellaneous pulmonary disorders. 163

Gene therapy for pulmonary arterial hypertension............. 163

Gene therapy for bleomycin-induced pulmonary fibrosis..... 164

Pulmonary complications of a1-antitrypsin deficiency......... 164

Gene therapy for asthma ... 165

Gene therapy for adult respiratory distress syndrome ........ 165

Gene therapy for lung injury..... 166

Gene therapy for bronchopulmonary