Lecture 2: Drug Targets Flashcards

1
Q

T or F

When a GPCR is activated the affinity of its G-protein alpha subunit for GDP is decreased

A

True

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2
Q

The receptors for a group of signaling molecules known as GFs are often:

A) Ligand-gated ion channels

B) GPCRs

C) Nuclear receptors

D) Membrane transporters

E) Receptor tyrosine kinases

A

E. Receptor tyrosine kinases

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3
Q

What are 3 targets of targeted anticancer drugs?

A

1) Monoclonal antibodies to GF receptors
2) Monoclonal antibodies to ligands of GF receptors
3) Multikinase inhibitors

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4
Q

What is inhibited by targeted anticancer drugs?

A

Upregulated GF signaling

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5
Q

Spironolactone is what type of drug?

Used to treat what?

A
  • Aldosterone receptor antagonist
  • Tx for chronic HTN and alleviates chronic heart failure
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6
Q

What is the MOA of the drug Verapamil?

A
  • Blocks L-type calcium channels = Calcium antagonist
  • Used to tx atrial and supraventricular arrythmia, angina pectoris, and HTN
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7
Q

What is an adverse effect of Verapamil?

A

Constipation

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8
Q

What is the MOA of Digoxin?

A

Inhibits Na+/K+-ATPase –> enhances cardiac contractility

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9
Q

Which pathology is Digoxin used to treat?

A

CHF

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10
Q

What do TF’s regulate the recruitment of?

A

Either promote (activators) or inhibit (repressors) the recruitment of RNA polymerase to specific genes

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11
Q

What are 5 GPCR ligands?

A

1) Biogenic amines
2) Peptides/proteins
3) AAs
4) Lipids
5) Nucleotides

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12
Q

What are the classes of GPCRs and their functions?

A
  • Gs: activates adenylyl cyclase and Src tyrosine kinase
  • Gi: inhibits adenylyl cyclase but activates Src tyrosine kinase
  • Gq: activates phospholipase C
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13
Q

What specific DNA sequence do TF’s bind to?

A

Response element

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14
Q

What is unique about insulin and IGF RTKs?

A

Contain 2 polypeptide chains, α and β, linked by disulfide bond

*Most RTKs possess a single polypeptide chain

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15
Q

List 5 hormones/cytokines that utilize a JAK-STAT pathway for signaling?

A

1) GH (somatotropin)
2) Erythropoietin
3) Leptin
4) Interferons
5) IL-2 to 10, and 15

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16
Q

IGF-1, VEGF, EGF, NGF, and PDGF are able to assert their actions through the use of which type of receptor?

A

Receptors with tyrosine kinase activity (RTK)

17
Q

What is the defining feature of a TF?

A

Presence of the DNA-binding domain

18
Q

What is unique about the effects of nuclear receptor drugs?

A

Effects can persist after the agonist concentraton has been reduce to zero

19
Q

Describe the mechanism of a steroid hormone activating its receptor?

How is the receptor inactivated?

A
  • In absence of hormone, hsp90 is bound and prevents folding into active conformation
  • Binding of a hormone ligand (steroid) dissociates hsp90 and permits conversion to active configuration
20
Q

What 3 types of drugs are inhibitors of voltage-gated Na+ channels?

A

1) Local anesthetics
2) Antiarrythmia drugs
3) Epilepsy drugs

21
Q

Activation of a Nicotinic acetylcholine receptor induces influx of?

Causes?

A
  • Na+
  • Membrane depolarization
22
Q

Nicotinic acetylcholine receptors are pentameric receptor found in what 2 locations?

A

1) Skeletal muscle
2) Neuronal cells

23
Q

What is the differene between the actions of excitatory and inhibitory NTs in terms of channels they open?

A
  • Excitatory (ACh and Glutamate) open cation channels –> depolarization –> APs
  • Inhibitory (GABA and Glycine) open anion channels –> hyperpolarization –> prevent APs
24
Q

GABA-A receptors are what type of channels and cause the influx of what?

Affects membrane potential how?

A

Anionic channels causing inward Cl- influx and hyperpolarization

25
Q

What 4 things are GABA-A receptors a target for?

A

1) Inhalation anesthetics
2) IV anesthetics
3) Ethanol
4) Hypnotic and anti-anxiety benzodiazepine drugs

26
Q

Propofol and neurosteroids modulate which subunit of GABA-A channels?

A

β subunit

27
Q

Ethanol and volatile anesthetics modulate which subunit of GABA-A channels?

A

α subunit

28
Q

Benzodiazepines modulate which subunit of GABA-A channels?

A

γ-subunit

29
Q

Point mutations in Ras are found in 90% of what type of cancer?

A

Pancreatic adenocarcinomas

30
Q

Point mutations in Raf are found in 70% of what type of cancers?

A

Melanomas

31
Q

Spironolactone targets which ion channels?

Leads to?

A
  • ENaC and Na+, K+ ATPase
  • Decreases reabsorption of Na+, decreasing BP, and helps to alleviate heart failure
32
Q

What is the effect of Verapamil on the SA and AV node; used therapeutically for what?

A
  • SA node = decreased HR
  • AV node = decreased AV contractility
  • Tx for atrial and supra-ventricular arrhythmia
33
Q

What is the effect of Verapamil on cardiomyocytes; used therapeutically for what?

A
  • Decreased contractility and O2 demand
  • Tx for Angina pectoris
34
Q

What is the effect of Verapamil on vascular smooth muscle; used therapeutically for what?

A
  • Vascular smooth muscle relaxation
  • Tx for HTN
35
Q

What is the effect of Digoxin on GI smooth muscle, brain nuclei and the SA and AV nodes?

Producing what side effects?

A
  • GI smooth muscle: increased contractility –> vomiting and diarrhea
  • Brain nuclei: enhanced neuronal activity and increased vagal activity –> vomiting, diarrhea, disorientation, confusion, visual disturbances, bradycardia, and slowed AV conductivity
  • SA and AV node: bradycardia and slowed AV conductivity
36
Q

What is the MOA of Etoposide?

A

Topoisomerase type II inhibitor –> DNA damage –> induction of p53 –> triggers apoptosis of cancer cells

37
Q

How does Etoposide work?

What are its therapeutic uses?

A
  • Causes DNA damage as a topoisomerase inhibitor leading to activation of p53
  • p53 induces expression of proteins causing release of proapoptotic proteins from mitochondria into cytosol
  • These proteins activate caspases to trigger apoptosis of a cancer cell
38
Q

What do SH2 and SH3 bind to, respectively

A

SH2: tyrosine kinases

SH3: proline rich

39
Q

What is SOS?

Actvates?

A
  • Encodes guanine nucleotide exchange factor
  • Activates Ras