week 7

Question 1

factors affecting individual drug response

Answer 1

1. disease state
2. genetic factor
3. environment
4. drug interaction
5. diet
6. weight
7. gender
8. age

Question 2

define mutation

Answer 2

occur when the number or order of bases in a gene is disrupted

Question 3

define polymorphism

Answer 3

a DNA sequence variation that is common more than 1% in the population

Question 4

where does polymorphism begin from

Answer 4

an inherited mutation

Question 5

4 types of mutations

Answer 5

1. insertion
2. deletion
3. duplication
4. inversion

Question 6

define single nucleotide polymorphism

Answer 6

DNA sequence variation that occurs when a single nucleotide in the genome sequence is altered

Question 7

two types of SNP classifications

Answer 7

1. synonymous = results in same protein

2. non-synonymous = results in different protein

Question 8

define wild protein

Answer 8

a protein that has the sequence that is found in the majority of the pop

Question 9

4 types of individual variation in drug response = drug given based on genetic makeup = pharmacogenomics

Answer 9

1. optimal responders = full benefits of the drug
2. sub-optimal responders = adverse affect but still respond to drug
3. non-responders = no response or adverse affect
4. adverse reactions = only toxic/adverse affect

Question 10

define pharmacogenomics

Answer 10

the study of how an individuals genetic inheritance affect the body’s response to drugs

Question 11

goal of pharmacogenomics

Answer 11

right dose, right drug, for the right patient

Question 12

define pharmacogenetics

Answer 12

• subset of pharmacogenomics
• targeted gene

= the study of how inherited variation affects drug response

Question 13

polymorphism at receptor level: A118 opioid receptor & what it leads to

Answer 13

• A to G substitution at nucleotide 118 = Asparagine –> aspartic acid amino acid change in the N-terminal domain of the mu-opioid receptor
• leads to drug addiction, stress responsivity & in treatment responses, including dependence & pain reduction

Question 14

polymorphism at enzyme target: VK epoxide reductase

Answer 14

warfin inhibits VKOR = reduce the synthesis of active clotting factors

the mutation - VKORC1 causes warfin resistance = carriers of this mutation require exceptionally high warfin dose to achieve effective anticoagulation = too much coagulation due to mutation

Question 15

what is a highly polymorphic enzyme

Answer 15

CYP2D6 - from the cytochrome P450 enzyme family

Question 16

drug example metabolised by CYP2D6

Answer 16

Nortriptyline - A tricyclic antidepressant

tamoxifen = selective estrogen receptor modulator for breast cancer

Question 17

polymorphism in P-glycoprotein & example

Answer 17

affect the drug responses = affects drug disposition

example: 3435T polymorphism affects digoxin disposition = for treating various heart conditions

Question 18

role of p-glycoprotein

Answer 18

a transporter that controls some drug absorption and entry into compartments (e.g. brain) or cells

SNPs identified:

• gut, liver, kidney = pumps drugs out
• brain endothelium = pumps drugs back into blood
• large protein

Question 19

define biological drugs & example

Answer 19

= contain active substance derived from or extracted from biological system (often administrated as injection or infusion)

examples: protein, antibodies, oligonucleotides used as drugs

Question 20

define first-generation drugs

Answer 20

similar to hormones, not as new

Question 21

define second-generation drugs

Answer 21

modified

Question 22

application of biological drugs

Answer 22

• therapeutic monoclonal antibodies
• recombinant hormones
• controlling gene expression

Question 23

what is the old way insulin & growth hormones (1st generation) were synthesised & the issues with it

Answer 23

purifying extracts to treat protein hormone deficiency

• use to cause issues because body identifies it to not be theirs
• transmission of diseases

Question 24

what is the new way insulin & growth hormones are synthesised

Answer 24

“genetic engineering” techniques

1. insert human gene into suitable expression system
2. harvest & purify the recombinant protein

Question 25

define plasmid

Answer 25

small, circular, double-stranded DNA molecule

Question 26

define protein expression system

Answer 26

refers to the type of living organism that is used to grow the desired protein

Question 27

example of common expression systems for recombinant biopharmaceuticals & the most used

Answer 27

1. bacteria = more used
2. yeast
3. mammalian

Question 28

what does it mean to engineer a protein

Answer 28

alter the protein prior to expression by changing the gene sequence

Question 29

reasons for changing the structure of the recombinant protein x3

Answer 29

1. modification of pharmacokinetic properties
2. creation of novel fusion or other proteins
3. reducing immunogenicity (humanising proteins) = less chance of causing disease

Question 30

examples of when PEGylation is added

Answer 30

1. size increase reduces kidney filtration
2. reduced accessibility for proteases & antibodies
3. hydrophilicity of PEG increases drug solubility

Question 31

when proteins are engineered what generation are they

Answer 31

second generation

Question 32

what is the suffix of monoclonal antibodies

Answer 32

-MAB e.g., infliximab, omalimuab

Question 33

defie antibodies

Answer 33

large proteins produced by activated b cells (plasma cells) which are important cells for our immune system

Question 34

what are the three effects of antibodies binding

Answer 34

1. neutralisation
2. aggulation
3. precipitation

= decrease effect = improve condition

Question 35

define epitope

Answer 35

the specific part of the antigen that binds to a specific antigen receptor on the surface of B cells

Question 36

how are monoclonal antibodies made

Answer 36

1. mousse is injected with antigen (protein want to make antibodies against)
2. spleen cells are extracted
3. spleen cells fused by myeloma cells (live forever)
4. hybridomas are made and the desired antibodies are extracted from those cells
   - they can be frozen and regrown and used

Question 37

pharmacokinetics of monoclonal antibodies

• Vd
• absorption
• oral availability
• specificity
• elimination

Answer 37

• large so difficult to cross membranes = decrease Vd & absorption
• very low oral bioavailability due to low absorption & because they are proteins that can be digested in the stomach
• high specificity = less off-target effect leading to less adverse affect
• majority broken down into peptides & amino acids (intracellular catabolism)
• endocytosis from receptor mediated degradation –> receptors in the cell surface bind to the antibody & internalise it, monoclonal receptor complex is then degraded in a lysosome

= renal impairment does not affect elimination of monoclonal antibodies

Question 38

comparisons between biologics (B) and conventional (C) drugs

Answer 38

1. size = B larger
2. synthesis
   = C identical & well-characterised (easy synthesis)
   = B unique = more complex & harder to characterise = harder to be reproduced
3. relationship between dose & effect
   = C usually predictable relationship
   = B complex mechanisms of action (high affinity binding, slow on and off rates (take while to leave), unusual shape D/R curves
4. pharmacokinetics
   = C oral administration, variable absorption & bioavailability, 2 phases metabolism, excretion of drug in urine or faeces
   = B parenteral administration (not through digestion), bioavailability high, long half-life, atypical biodistribution (large affinity so small amount = large affect) & removal mechanisms)
5. toxicology & adverse effects

= C variable, possible drug interactions

= B immunogenicity (allergic reaction), few drug interactions, generally few adverse effects

Question 39

what has a longer half life: antibodies or plasma proteins

Answer 39

antibodies. specifically IgG (around 21 days) compared to IgA and IgM (around 6 days)

Question 40

define gene therapy

Answer 40

= the addition of genetic material to cells to precent. alleviate or cure disease

= use of oligonucleotides

Question 41

2 applications of gene therapy

Answer 41

• cure diseases caused by single defective gene such as CFB
• improvement of conditions with or without a genetic component, including malignant, neurodegenerative and infectious diseases

Question 42

role of antisense oligonucleotide in gene therapy

Answer 42

= binds complementary (“sense”) mRNA sequences & block translation

Question 43

administration of antisense oligonucleotide

Answer 43

parental administration widely distributed except CNS

Question 44

issue with gene therapy

Answer 44

delivery into the cells

• viral vectors (should be safe, efficient, selective, produce a long lasting expression of therapeutic gene)