Pharmacology 401 Exam 2 Material: Dr. Moon

Front 1

What is an SNP and what is its relevance to pharmacogenomics?

Back 1

SNP = Single Nucleotide Polymorphism

May be associated with diseases/genetic traits; can assess risk w/o sequencing whole genomes

Front 2

Define pharmacogenomics.

Back 2

The application of genomic methods to study variability in drug responses

Front 3

Define pharmacogenetics.

Back 3

The study of how inherited
variation in genes affects drug response

Front 4

Why does it suck to be a slow acetylator?

Back 4

1. get lupus more often
2. procainamide-induced antinuclear ab's
3. isoniazid polyneuropathy

Front 5

What is the most common hereditary enzymatic disorder?

Back 5

Glucose-6-phosphate dehydrogenase (G6PD) deficiency; sensitivity to oxidizing drugs, fragile RBC's

African americans

Front 6

Advantage of G6PD deficiencies?

Back 6

Partial immunity to malaria

Front 7

Consequence of Thiopurine methyltransferase (TPMT) deficiency?

Back 7

can't break down thiopurines fast enough --> get TGN's (thioguanine nucleotides)

cytotoxic b/c function as base analogs

Front 8

What allele is associated with Alzheimer's Disease?

Back 8

Apolipoprotein E-ε4

associated with increased onset of familial Alzheimer's and no benefit from cholinesterase Tacrine

Front 9

What is PLX4032?

Back 9

Melanoma drug

Designed using gene sequencing to specifically target cancerous BRAF kinase enzyme and leave WT alone

Front 10

Transition Mutation

Back 10

purine --> purine
pyrimidine --> pyrimidine

A <--> G
C <--> T/U

Front 11

Transversion Mutation

Back 11

purine <--> pyrimidine

A <--> T/U
C <--> G

Front 12

Effect of 5-Br (5-Bromouracil)?

Back 12

Point mutation

Replaces T but pairs with G --> A/T to G/C mutation

Front 13

Effect of base deamination?

Back 13

C --> U + NH3

G/C --> A/U base pair point mutation

Front 14

Effect of alkylation of DNA?

Back 14

Nitrogen mustards and nitrosureas

impairment of transcription, replication, or repair mechanisms --> lose base pair

Front 15

Examples and effect of DNA intercalating agents?

Back 15

Acridine dyes, Anthracycline abx (Actinomycin D)

slip into DNA ladder --> frameshift mutations during replication; blockage of polymerases.

Effect is reversible.

Front 16

Bleomycins MOA?

Back 16

Chelate iron --> intercalate into DNA and covalently bind T --> iron generates free radicals --> break DNA strand

Front 17

Examples and effects of DNA crosslinking agents?

Back 17

mitomycin C, cisplatin, nitrogen
mustards

irreversibly (covalently) bonds and blocks transcription of DNA

Front 18

Modes of gene amplification in response to drug?

Back 18

-mini-chromosome with extra copies
-extra copies of gene replicated on same chromosome

Front 19

What genes are typically amplified in response to drug?

Back 19

-drug target
-efflux pumps (membrane transporters)
-oncogenes (Her2/neu in breast cancer)

Front 20

Take home points about antisense oligonucleotides?

Back 20

18-21nt ssDNA binds target mRNA

must be present in great molar excess to work

may modify phosphoester bond or sugar backbone to +stability, block translation, induce RNases etc.

Front 21

Take home points about Ribozymes?

Back 21

enzyme made of RNA

bind and cleave/destroy/fix target RNA's

can clone into cell with constitutive promoter, works against viral genes in host cell (HIV)

Front 22

Take home points about drugs that induce Triple Helix formation?

Back 22

intercalate w/DNA strand and interfere w/transcription (turn off promoter etc)

nonstandard base pairing.

need less drug (target gene not mRNA) mothership vs drones

Front 23

Take home points about siRNA?

Back 23

Small Interfering RNA's

long dsRNA introduced into cell, cleaved by DICER

strands separate and bind RISC (RNAi Silencing Complex)

--> induce degradation of target mRNA by SLICER

Front 24

Principle behind Etanercept?

Back 24

Enbrel, for RA

"decoy" higher affinity TNF receptor bound to Fc region of IgG --> TNF binds Etanercept preferentially

Front 25

Function of Corticosteroids?

Back 25

inhibit T cell proliferation, expression of cytokines

Front 26

Function of Cyclosporine?

Back 26

Fungal polypeptide that interferes w/lymphocyte proliferation

organ transplant rejection, psoriasis, severe atopic dermatitis

Front 27

Requirements for antigenicity?

Back 27

-Foreign
-Size: larger = more antigenic (also small HAPTEN bound to large carrier molecule; polymerization of drug molecules)
-metabolism into more antigenic compounds

Front 28

Quick definition of humoral immune response?

Back 28

B-cell and antibody-mediated response

Front 29

Quick definition of cellular immune response?

Back 29

Cytotoxic/Killer T and Helper T cell mediated response

Also involves NK Natural Killer T cells.

Front 30

True or False: Severe allergic reaction can occur upon primary exposure.

Back 30

False

Need primary exposure and formation of IgG --> immune memory to stage severe atopic response

Front 31

Examples of Pseudoallergic responses?

Back 31

-drug activates allergy-related system (ex. triggers mast cells to release histamine)
-drug can cause cell damage and mimic immune mediated effects

Front 32

Type I hypersensitivity reaction

Back 32

Anaphylactic Reaction

Ag binds IgE on mast cells --> anaphylaxis, bronchospasm, edema

Front 33

Type II hypersensitivity reaction

Back 33

Cytolytic reaction

Ag binds cell membranes and IgG/M --> agglutination, complement-mediated lysis

blood transfusions; hemolytic diseases

mimics pseudoallergic rxn

Front 34

Type III hypersensitivity reaction

Back 34

Arthrus Reaction

high conc of Ag-Ab complexes deposited on tissues, clogs capillaries, etc.--> skin rash, glomerulonephritis, LOCAL rxns

lymphocytes target Ab's --> tissue casualties

Front 35

Type IV hypersensitivity reaction

Back 35

"Delayed" Cell Mediated reaction

NO antibodies involved!

WBC's recruited to site of inflammation; takes days to manifest (not mins to hours)

Front 36

Most common source of drug allergy?

Back 36

Penicillins

1-10% of population is allergic.

Front 37

What is wnt? What is beta-catenin?

Back 37

Wnt = extracellular signaling molecule. Inhibits degradation of B-cat.

Beta-catenin = intracellular transcription factor that is usually Phos and degraded.

Front 38

Action of beta-catenin?

Back 38

Transcription factor. When active, promotes cell REGENERATION and PROLIFERATION.

Front 39

Significance of Wnt/B-cat signaling in Alzheimer's disease?

Back 39

signaling is attenuated in Alzheimer's disease; activating it may be beneficial

Front 40

Therapeutic applications of Wnt/B-cat signaling modulation?

Back 40

-encourage damaged/wounded tissue regeneration
-ameloriate alzheimer's dz sx
-enhance effectiveness of hematopoietic stem cell therapy

Front 41

Function of levamisol?

Back 41

tx colorectal cancer; stimulates T cell proliferation and activation

Front 42

Therapeutic applications of Recombinant proteins, eg. interferon/IL-2?

Back 42

IFN: stimulate cytotoxic T cell activities;

IL-2: Stimulate B/T cell differentiation and proliferation

Front 43

Which portion of immune response is mostly effective against extracellular invasions?

Back 43

Humoral Immune Response

Front 44

Which portion of immune response is mostly effective against inracellular invasions and tumor cells?

Back 44

Cellular Immune Response (Killer/Cytotoxic T cells)

Front 45

General principle of Ames test?

Back 45

Detect mutagenicity of drug by observing frequency of his- auxotrophic bacteria mutating and reverting to WT

Front 46

How is Ames test modified to detect mutagens generated via oxidative metabolism?

Back 46

Same thing but add microsomes from liver homogenate (add liver juice to plate 'cause it's got P450s in it)

Front 47

How is Ames test modified to detect mutagens generated via reductive metabolism?

Back 47

Same thing but add enzymes from bacterial gut flora that usually carry out reductive metabo in humans

Front 48

General principle of Mammalian Cell Culture Test?

Back 48

Normal cells lack HGPRT --> killed by 8-azoguanine.

Expose cells to test chemical for a while then dump 8-azoguanine on it and see if you got HGPRT mutants

Front 49

What is the major obstacle to killing cancer cells?

Back 49

Cells' ability to repair DNA!

Front 50

Average error rate (1 per __ nt's) in cell DNA replication?

Back 50

1 in 10,000.

Front 51

Nucleotide Excision Repair

Back 51

broadest DNA repair mecha

helicases open DNA @ damage site; RPA holds it open

endonucleases cut out damaged nt's and ~30nt in surrounding area.

DNA pol fills in gap correctly

Front 52

Base Excision Repair

Back 52

more specific than NER; fixes damage resulting from normal cell activities.

-glycosylases cut out ONLY damaged bases
-endonuclease opens DNA strand
-DNA pol fills in; ligase seals the nicked strand

Front 53

Double Strand Break Repair

Back 53

fixes damage from x-rays, chemicals, drugs, etc.

MUST be fixed before mitosis!

1. homologous recombination: use homologous xsome as template to fix damaged portion
2. sticky end joining (just slap it back together)

Front 54

Repair of damage caused by alkylating agents

Back 54

Usually methylated guanines.

MGMT (O6-MethylGuanine Methyltransferase) removes methylated guanine from sugar base so it isn't used as a template. MGMT is destroyed in the process.

Front 55

Mismatch Repair

Back 55

Cell scans DNA for damage.

DNA pols know to use methylated strand (older strand) as correct template to fix damage

Front 56

How can methylguanine screw with Mismatch Repair?

Back 56

Methylguanine is an incorrect base but since MMR detects methylation it will be seen as "correct" by repair machinery

Front 57

Which syndromes result from inherited defects in Base Excision Repair?

Back 57

NONE

Front 58

Which syndromes result from inherited defects in Nucleotide Excision Repair?

Back 58

Xeroderma Pigmentosa
Cockayne Syndrome

Front 59

Which syndrome results from inherited defects in Double Strand Break Repair?

Back 59

Ataxia telangiectasia

Front 60

Which syndrome results from inherited defects in Mismatch Repair?

Back 60

Hereditary Colon Cancer

Front 61

Retinoids: why are they teratogenic?

Back 61

involved in regulating early embryonic development via signal transduction pathways that regulate a wide range of genes

Front 62

Why are hormonal drugs/antagonists teratogenic?

Back 62

Mess up hormonal signaling pathways necessary for normal development

Front 63

Pregnancy Category A

Back 63

Totally ok to use at all stages of pregnancy

Front 64

Pregnancy Category B

Back 64

animal or human studies say not much risk

Front 65

Pregnancy Category C

Back 65

animal studies show teratogenicity, no well controlled human studies

Front 66

Pregnancy Category D

Back 66

has been shown to cause harm. cost/benefit analysis

Front 67

Pregnancy Category X

Back 67

NEVER OK

Front 68

Xeroderma Pigmentosa
Type/qty of mutation?
Cancer risk?

Back 68

impaired NER --> can't repair UV induced thymine dimers --> severe photosensitivity, neurodegeneration

any of 7 genes involved; autosomal recessive mutations

>1000x higher risk of skin cancer.

Front 69

Cockayne Syndrome
Type/qty of mutation?
Cancer risk?

Back 69

UV sensitivity, organ degeneration, early aging,

single autosomal recessive mutation

NO increase in cancer (UV damage repair system is intact)

Front 70

Ataxia telangiectasia
Type/qty of mutation?
Cancer risk?

Back 70

defective DSB repair --> myriad of problems

single autosomal recessive mutation (ATM, mutated)

predisposed to cancer, immunosuppression, neurodegeneration, etc.

Front 71

Werner’s Syndrome
Type/qty of mutation?
Cancer risk?

Back 71

defective DNA repair --> high # of xsome abnormalities; early aging, drug sensitivities

one autosomal recessive mutation

No increased cancer risk

Front 72

Bloom’s Syndrome
Type/qty of mutation?
Cancer risk?

Back 72

defective DNA repair --> high # of xsome abnormalities; butterfly marking on face, drug sensitivities

one autosomal recessive mutation

No increased cancer risk

Front 73

Fanconi Anemia
Type/qty of mutation?
Cancer risk?

Back 73

Defective DNA strand break repair --> anemia

multiple genes; autosomal recessive

20% develop cancer

Front 74

Why are RBC's fragile in those with G6PD insufficiency?

Back 74

Membrane proteins damaged by oxidizing drugs --> fragile --> lyse when passing through spleen, capillaries, etc.

Front 75

What types of drugs are hazardous to those with G6PD deficiency?

Back 75

oxidizing drugs

(ex. Primaquine, antimalarial used during Korean War)

Front 76

What genes mentioned in lecture are most commonly amplified in response to drugs?

Back 76

Those coding for DHFR (Dihydrofolate reductase) during tx w/Methotrexate

Alternately: membrane transporters (drug efflux pumps) --> drug resistance

Front 77

Function of Antithrombin III (AT-III)?

Back 77

Cleave and inactivate clotting factors, incl. thrombin (duh).

Affinity for thrombin is increased when AT-III is bound to heparin.

Front 78

How does TSH exert its effects?

Back 78

increases cAMP in thyroid cells --> increased secretion of T3/T4

Front 79

How does TRH exert its effects?

Back 79

Binds receptors on TSH producing cells in anterior pituitary --> Trigger IP3/Ca2+ signaling pathway --> TSH release

Front 80

What genes mentioned in lecture are most commonly amplified in breast cancer tumors?

Back 80

Her2/neu

abnormal levels in ~30% of all breast cancers

Front 81

Function of RNAse H?

Back 81

cleave RNA/DNA heteroduplexes in cytosol.