1. GENE THERAPY: A brief overview
D. Bunker
TAS USANZ 2014

2. Overview What is it How can it be achieved
Transfection
Transduction
Adeno-associated viral vectors
Example  achieving transplant tolerance
Gene therapy in prostate cancer research

3. Gene therapy - on the rise

4. What is it? Using genes to treat or prevent disease Methods:
Expression
Repair
Silencing

5. How do we get genes in?
All methods require getting new genes in i.e. transfer of genetic material using a vector
Transfer accomplished by:
Transfection (non-viral)
Transduction (viral)

6. Transfection p c + pDNA GAG HSR - - Variable, low-level expression
Physical  injection, sonoporation
Chemical  Ca-Phos-DNA
Electrical  ‘electropores’
Synthetic Vectors  lipopolyplex vehicles
pDNA p c - + -
GAG
HSR
Variable, low-level expression

7. Transduction
Use of a virus to confer uptake of the transgene into host DNA
Stable, high-level expression
Figure:

8. Adeno-associated virus (AAV)

9. Adeno-associated Virus (AAV)
REPICLATION DEFECTIVE  requires helper virus for replication
‘NON-PATHOGENIC’
Infects DIVIDING AND QUIESCENT CELLS
EXTRACHROMOSOMAL or INTEGRATES IN A PREDICTABLE PATTERN

10. AAV genomics

11. Recombinant AAV (rAAV)
Recombinant AAV  can influence the structure of the virus to express what you want where you want with maximum efficiency

12. Example – Transplant tolerance

13. Normal allograft function without immunosuppression
Clinical impetus
Operational tolerance :
Rejection driven by MHC mismatches: if we can tolerise to donor antigens can we prevent the rejection process?
Normal allograft function without immunosuppression

14. Liver tolerance effect
Propensity to induce tolerance to neoantigens
Can gene transfer of donor MHC to recipient liver confer tolerance?

15. Murine Skin Allograft ModelIA IE
B10 k
178.3
k,b
Control group:  naïve B10.BR recipients
Experimental group:  B10.BR recipients given rAAVKb 5x 1010 vgc day 0, transplanted day 7

16. Kb Transduction
rAAVKb 5x1011 vgc via penile vein  rapid, high-level, stable hepatic expression of Kb on hepatocytes 
B10.BR
rAAVKb
C57BL/6

17. No significant inflammatory infiltrate after rAAVKb 5x1011 vgc
Non-immunogenic
No significant inflammatory infiltrate after rAAVKb 5x1011 vgc
CD4
CD8
B220
F4/80

18. Tolerance to Allografts
Transplanted Day 0
rAAVKb confers tolerance to allografts
control MST 16 days, rAAVKb treated mice harvested at day 250
Day 250 post transplant

19. Role in Prostate Cancer

21. Gene Therapy for Prostate Cancer
Goals:
Enhance cure rate of primary therapy
Treatment option for metastatic disease/hormone resistant
Use of adenoviral vectors selective for PCa cells
Delivery routes
Modes of action: Oncolytic vs. Radio-sensitisation (adenovirus replication inhibits DNA repair pathways  susceptible to radiation)
Local therapies  lack of sustained efficacy
Metastatic therapies  poor therapeutic efficacy

22. Examples: Phase III ProstAtakTM suicide gene therapy (Advantagene)
ProstAtak™ + EBRTx for intermediate-high risk localized prostate cancer
Outcome: DFS, PCSS, OS
Phase II: prolonged Tcell activation against PCa cells and 75% decrease in recurrence
?First vaccine against cancer recurrence

23. Conclusion Novel strategy for addressing many types of disease
Main roles roles are in single gene disorders, immunotherapy and cancer
Expanding role in prostate cancer research (Clinical adenoviral gene therapy for prostate cancer. Hum Gene Ther Jul;21(7):807-13)