Proteins & Peptides (Classes 19-20)

Question 1

Give an example of a commonly used protein drug?

Answer 1

Insulin

Question 2

What are some benefits of protein therapy?

Answer 2

High specificity, target any defective gene, broad range, easier FDA approval

Question 3

Give an example of an anti-cancer protein therapy (besides monoclonal antibodies)?

Answer 3

Herceptin

Question 4

What is the largest class of therapeutic proteins?

Answer 4

Antibodies

Question 5

Name 4 ways protein therapies deliver their therapeutic effects to the body.

Answer 5

Replace a deficient or abnormal protein, Augment existing pathway, provide novel function, Interfere with a molecule or pathway, Deliver a therapeutic payload

Question 6

What are some classes of protein therapies?

Answer 6

Enzymes, antibodies, blood factors, hormones, interferons, interleukins

Question 7

What are some clinical conditions that protein therapies are used for?

Answer 7

Diabetes, Cancer, Transplant rejection, Crohn’s disease

Question 8

What classifies a peptide drug vs a protein drug?

Answer 8

Peptide - 50 Aas or less; Protein - 100 to 1000s of Aas

Question 9

What is the major disadvantage of protein therapy?

Answer 9

Maintaining stability & high dosing; efficacy requires maintaining 3D structure/high dosing can lead to aggregation or precipitation

Question 10

What are 4 ways to cause denaturation of proteins (not the chemical rxns)?

Answer 10

Adjust temp, Adjust pH, agitation, Use solvents

Question 11

What are 3 physical issues that can affect protein stability/efficacy (other than denaturation & not chemical reactions)?

Answer 11

adsorption, aggregation, precipitation

Question 12

What are 4 chemical reactions that can affect protein stability/efficacy?

Answer 12

Deamidation, Oxidation, hydrolysis, racemisation, Isomerisation, disulfide exchange

Question 13

What are 2 common sites of attack for protein oxidation (think amino acid residues)?

Answer 13

methionine & cysteine

Question 14

What are four ways to cause oxidation in proteins?

Answer 14

Irradiation, Air pollutants, Inflammation, Reactive Oxygen Species

Question 15

What amino acid residues are affected in deamidation?

Answer 15

asparagine & glutamine

Question 16

What are 2 ways to cause deamidation in a protein?

Answer 16

change pH, change temp

Question 17

What does TRAIL do on a molecular level?

Answer 17

Induces cell death via TNFa

Question 18

What is TRAIL used for clinically?

Answer 18

Kill cancer cells

Question 19

What is the goal of transfection?

Answer 19

Transfer DNA into a cell

Question 20

In recombinant DNA tech, what do you use to cleave the host plasmid?

Answer 20

Restriction Endonucleases

Question 21

In recombinant DNA tech, what is the name of the process of closing the 2 ends of the open plasmid after you have inserted new DNA?

Answer 21

Annealing

Question 22

In recombinant DNA technology, what do you use to put a plasmid with your new gene inside a host cell?

Answer 22

transfection reagent

Question 23

What is the major challenge of recombinant DNA technology (other than being expensive)?

Answer 23

Scaling up; Requires scaling of producer cells in sterile environment

Question 24

What is one challenge to using bacterial cells for recombinant DNA technology?

Answer 24

bacteria cannot perform post-translational modifications to proteins

Question 25

Can protein therapies have generic versions?

Answer 25

No. Only biosimilar versions.

Question 26

Procrit and Eprex are examples of what kind of protein therapy?

Answer 26

EPO replacement

Question 27

What is the origin of paclitaxel (ie where does it come from)?

Answer 27

Pacific Yew bark

Question 28

What are some problems with using cremophor as a dissolution agent?

Answer 28

axon degeneration/demyelination; Rash, chest pain, tachycardia, peripheral neuropathy

Question 29

What challenge did the use of human albumin overcome in the development of paclitaxel drug for breast cancer?

Answer 29

hydrophobicity/solubility challenge

Question 30

What is the drug Abraxane comprised of?

Answer 30

paclitaxel and human albumin

Question 31

What is Abraxane used for?

Answer 31

Metastatic cancer (study was on metastatic breast cancer)

Question 32

What are 4 things proteins are susceptible which make protein therapies a challenge?

Answer 32

Aggregation, Fragmentation, Oxidation, Deamidation

Question 33

What is a major challenge for protein therapy in liquid or subQ formulations?

Answer 33

Requires high dose for delivery

Question 34

Name 3 ways to prevent protein breakdown

Answer 34

lyophilization, polymer encapsulation, cell-based delivery system, virus-based delivery system

Question 35

What are 4 ways to prevent protein aggregation in a protein therapy?

Answer 35

lower temp, adjust pH, add stabilizing agents, Add detergents

Question 36

What do detergents do to protect proteins?

Answer 36

Shield hydrophobic regions

Question 37

What is the process of freeze-drying and dehydrating a protein therapy called?

Answer 37

lyophilization

Question 38

How much residual water should remain in a lyophilized protein?

Answer 38

1-8%

Question 39

What is the key to rehydration after lyophilization of a protein therapy?

Answer 39

Slow rate of rehydration; too fast and the protein will not regain native conformation

Question 40

What is one way to provide a continual delivery system of protein based therapies?

Answer 40

Cell-based delivery system

Question 41

Name 3 requirements for cell-based therapies

Answer 41

Must be engineered in genome, must be secreted or expressed across membrane, Must be a protein therapy (not a small molecule)

Question 42

What is the term used to describe when a cell used in cell-based therapy navigates to the site of pathology?

Answer 42

homing

Question 43

How does viral gene delivery work?

Answer 43

Gene is engineered into genome, Virus delivered into target cells, cell starts producing proteins that initiate curative effect

Question 44

What are the roles of the variable and constant regions of an antibody?

Answer 44

Variable -> binds the epitope; Constant -> initiates immune response

Question 45

What are 4 uses for antibody therapies in targeting cancer cells?

Answer 45

block cancer-promoting receptors, localize lethal drugs to specific cells, localize radioactive molecules to kill cancer, localize drug-loaded nonoparticles

Question 46

What are some mouse (murine) antibody drawbacks?

Answer 46

allergic reactions, short half-lives, inefficient targeting

Question 47

What is the term for a mouse antibody and what is its suffix?

Answer 47

Murine; momab/monab

Question 48

What is a term for a mouse Fab region grafted onto a human backbone antibody called? Suffix?

Answer 48

Chimeric; Ximab

Question 49

What is the term for a mouse hypervariable region grafted onto a human backbone antibody called? Suffix?

Answer 49

Humanized; Zumab

Question 50

What is the suffix for a fully human antibody?

Answer 50

Umab

Question 51

What antibody type has the longest half-life?

Answer 51

Recombinant Humanized

Question 52

What are some challenges of monoclonal antibodies?

Answer 52

low potency, difficult/expensive to develop, low patient compliance with dosage form/admin schedule, hypersensitivity/immune rxns, Formulation/stability issues

Question 53

What humanized monoclonal antibody therapy is used for brain tumors?

Answer 53

Bevacizumab

Question 54

What is cetuximab used for?

Answer 54

Cancer