Deck 16: Gene Delivery

Question 1

The major limitation associated with the use of AAV vectors is:

A) AAV has a single DNA genome.
B) AAV is a potent immunogenic.
C) AAV is neurotropic.
D) AAV has limited loading capacity for exogenous genes.
E) AAV is randomly inserted into the host gene and can lead to cancers.

Answer 1

D

Question 2

To generate replication deficient adenoviral vectors,which of the following genes should be deleted?

A) E1.
B) E3.
C) E4.
D) L1.
E) L2

Answer 2

A

Question 3

What was the method of gene delivery?

A) Viral vector - adenovirus.
B) Viral vector - retrovirus.
C) Viral vector - herpes simplex virus.
D) Physical method - electroporation.
E) Chemical method - lipoplex.

Answer 3

B

Question 4

The trial demonstrated considerable success. However,there were serious drawbacks. What was the major drawback in the trial?

A) Massive tissue damage at the site of application.
B) Systemic toxicity of liposomes content.
C) Systemic toxicity of gene product.
D) Severe immune induction.
E) Activation of oncogenes and leukemia development.

Question 5

The following enzymes are components of retroviruses:

A) Reverse transcriptase.
B)
B) Integrase.
C) RNA polymerase.
D) Both a +

Question 6

To date,which viral vector has been tested in clinical trials the most?

A) Adenovirus.
B) Lentivirus.
C) Adeno-associated virus.
D) Vaccinia virus.
E) Herpes simplex virus.

Question 7

Chemical methods of gene delivery are advantageous in being:

A) Safer than viral vectors.
B) Significantly efficient,especially in in vitro systems.
C) Permissive for targeted delivery.
D) Permissive for controlled release systems.
E) All of the above.

Question 8

Gold particles have been utilized in gene delivery by the following methods:

A) Viral methods.
B) Chemical methods.
C) Physical methods.
D) Both b + c

Question 9

Physical methods of gene transfer utilize the following types of forces to facilitate gene transfer EXCEPT:

A) Electrical pulse.
B) Fluid pressure.
C) Ultrasound waves.
D) Ballistic punch
E) Gravitation force.

Question 10

Physical methods mediate successful gene delivery by the following mechanism:

A) Inducing endocytotic pathway to facilitate DNA entry.
B) Activating receptors on cell surface to facilitate DNA uptake.
C) Activating transcriptional factors for transgene expression.
D) Transient perforation of cell membrane to allow DNA entry.
E) Protection of DNA from degradation by deactivating serum and tissue nucleases.

Question 11

The followings would be considered proper applications of gene delivery using direct needle injection EXCEPT:

A) Transgenic animals and recombinant cell lines production.
B) Single cell genetic assays involving nuclear DNA transfer.
C) DNA delivery to mitochondria.
D) Correction of genetic disorder in liver.
E) DNA vaccination

Question 12

Gene delivery by gene gun is challenged by:

A) The accompanied tissue damage.
B) The need for special device.
C) Transfection is limited to the cells in path of particles.
D) Low levels of transgene expression.
E) All the above.

Question 13

Cavitation-mediated membrane deformation is the underlying mechanism of gene delivery of:

A) Electrporation.
B) Sonoporation.
C) Magnetofection.
D) Photoporation.
E) Hydrodynamic gene delivery.

Question 14

Gene delivery to plant cells can be achieved by the following methods:

A) Viral vectors.
B) Gene gun.
C) Sonoporation.
D) Both a + c
E) All the above.

Question 15

Photoporation gene delivery is challenged by the following:

A) Relatively high cost.
B) Limited capacity of tissue penetration,and hence low transfection efficiency.
C) Accompanied tissue damage.
D) Both a + b.
E) Both a + c.

Question 16

There is an increased safety concern of magnetofection in the following case:

A) When the brain is the intended target tissue.
B) When the size of DNA plasmid is larger than 5 kb.
C) When multi-dosing regimen is required for disease management.
D) When the target tissue is internal rather than superficial tissue.
E) None of the above.

Question 17

Which one among the following physical methods has been applied for in vivo cell delivery?

A) Electroporation.
B) Hydrodynamic delivery.
C) Sonoporation.
D) Magnetofection.
E) Photoporation.

Question 18

The efficiency of hydrodynamic gene delivery is determined by the following:

A) The speed of injection of DNA solution.
B) The volume of injected DNA solution.
C) The anatomical structure of target organ,and its vasculature.
D) Both a + b.

Question 19

Which of the following tissue is unlikely to be transfected with hydrodynamic gene transfer?

A) Connective tissue.
B) Muscles.
C) Liver.
D) Kidneys.
E) Pancreas.

Question 20

The primary purpose for DNA complexation with cationic polymers and lipids in chemical methods of gene transfer is:

A) To confer controlled release feature of gene delivery system.
B) To protect DNA from serum and tissue nucleases.
C) To overcome endothelial cell barrier.
D) To confer preferential accumulation of gene delivery systems in RES tissues.
E) To facilitate cytoplasmic and nuclear transport of DNA once being inside cells.

Question 21

PEG significantly enhances the efficiency of chemical methods of gene delivery by:

A) Prevention of complex aggregation.
B) Prevention of nonspecific interactions of DNA complexes with serum proteins.
C) Prevention of opsonization and subsequent uptake by liver macrophages.
D) Allowing fusion of targeting ligands to the tip of PEG molecules and enhanced targeting efficiency.
E) All the above.

Question 22

Which one of the following is NOT true about targeted gene delivery?

A) Coating of DNA complexes with folate-based chemical conjugates helps specific targeting of cells expressing folate receptors.
B) pH sensitive complexes are acid-sensitive complex that disassembles and release DNA at certain pH values of the environment.
C) Cancer specific gene delivery is achievable upon coating DNA complexes with antibodies recognizing cancer specific antigens.
D) Targeted gene transcription is the use of synthetic promoters helping in preferential accumulation of DNA complexes in cells where these promoters are active.
E) Colon cancers can be transcriptionally targeted by using promoters activated by β-catenin pathway.

Question 23

Upon internalized by endocytosis process,the fate of DNA complexes could be any of the following EXCEPT:

A) Recycling endosomes,where complexes are returned to cell surface.
B) Proceed via late endosomes to fuse with,and get degraded in lysosomes.
C) Proceed via late endosomes and fuse with nuclear membrane for nuclear transport.
D) Escape from endosomes and release into cytoplasm.
E) None of the above.

Question 24

The following are true about proton sponge effect EXCEPT:

A) It describes the inflow of water and ions into endosomes and subsequent endosomal rupture and content release.
B) It is proportional to the number of ionizable amine groups in polymers.
C) It is more prominent in early endosomes than in late endosomes.
D) The more proton sponge effect,the higher intracellular bioavailability of DNA.
E) None of the above.

Question 25

Endosomal escape of DNA complexes can be enhanced by:

A) Enhanced proton sponge effect.
B) Stimuli-responsive lipids/polymers,such as pH-sensitive sulfhydryl reduction that results in membrane destabilization.
C) Endosomal enzymatic degradation that activate derivatives to fuse with the endosomal membrane and release DNA complexes.
D) Lysosomotrophic agents,such as chloroquine.
E) All of the above.

Question 26

Physical methods of gene delivery are challenged by the following:

A) Local tissue damage at the site of application.
B) Specialized instrument is required to perform the procedure.
C) Optimized procedure parameters are required for different types of tissues.
D) Most physical methods have limited in vivo efficiency compared to viral methods.
E) All of the above.

Question 27

The approach of isolating cells from patients,introducing therapeutic genes to these cells in culture,and return them back to patient body is called:

A) In vitro gene therapy.
B) In vivo gene therapy.
C) Ex vivo gene therapy.
D) In sito gene therapy.
E) None of the above.

Question 28

Gene therapy aims to cure gene tic disorders by the following strategies:

A) To replace a missing or defective gene with functional version.
B) To augment pathologically insufficient endogenous gene function.
C) To block the expression of disease causing gene.
D) Both a + c
E) All the above

Question 29

Adeno-associated viral vectors can be used to transduce dividing and non-dividing cells with high efficiency.

Question 30

DNA precipitates with inorganic salts,such as calcium phosphate mediate gene delivery by physical approaches.

Question 31

Gene gun is advantageous in being noninvasively applicable to deliver genes to the internal organs such as liver.

Question 32

Electroporation gene delivery is efficient enough to transfect tissue when the distance between the two electrodes is close to 10 cm.

Question 33

The impact of physical force in hydrodynamic delivery is on the endothelial cells and the targeted parenchymal cells of target organs,rather than on target cells only.

Question 34

Integration into host genome is always undesirable in gene delivery trials.

Question 35

To overcome colloidal stability issues of lipoplexes and polyplexes,lower ratios of lipids/polymers to DNA are preferred.

Question 36

DNA complexes of sizes up to 100 nm can extravasate across liver vasculature.

Question 37

Targeted gene delivery by thermosensitive DNA complexes provides spatial control of DNA release by applying heat to targeted area for enhanced DNA release

Question 38

Polyplexes have higher potential for endosomal escape than lipoplexes.

Question 39

Unlike viral methods,the efficiency of chemical methods of gene delivery has nothing to do with dividing vs non-dividing cells.

Question 40

Apart for hydrodynamic and electroporation,physical methods have demonstrated effectiveness so far in in vitro systems only.