Theme 2 Lecture 4 Brief History of Drug Discovery Flashcards

1
Q

Describe the evolution of drug screening and lead discovery

A

The beginning was the discovery of penicillin, then receptor binding assays, recombinant DNA technology, HTS and MTS

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2
Q

Explain the evolution of classical in vitro and in vivo pharmacology.

A

In vitro tissues and in vivo measurements (blood pressure/HR). Was limited by lack of gene sequences and protein structures. However had quantitative agonism and antagonism.

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3
Q

Identify key blockbuster drugs

A

Beta blockers
Histamine h2 antagonists
Beta 2 adrenoreceptors
5-HT receptors
Dopamine D2 receptor antagonists
CCBS

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4
Q

Explain molecular target-based screens

A

Chemical libraries
HTS-using automated systems to test thousands to millions of compounds rapidly.
High content screening
Low successes as drugs usually fail in clinical trials

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5
Q

List examples of Screening Technologies

A

FLIPR-Ca2+
NanoBRET
Reporter Genes
Label Free

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6
Q

Intracellular Calcium

A

Fluo4AM detects changes in calcium levels in response to the GPCR activation

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7
Q

GPCR activation pathways calcium via subunits

A

Gq and Gi/o which modulates via Gβγ subunits.

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8
Q

What does BRET stand for?

A

Bioluminescence Resonance Energy Transfer

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9
Q

Explain how BRET works?

A

Uses N-terminal Nluc tag on the (GPCR)
Measures the energy transfer between NanoLuc and the fluorescent ligand.

Thus showing Ligand Binding

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10
Q

How do reporter genes work for cell signalling?

A

Reporter genes are luciferase and GFP.
These measure the transcriptional activity resulting from GPCR signalling.

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11
Q

What is DMR

A

Dynamic mass redistribution

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12
Q

Explain label free technologies

A

Monitors changes in the cell monolayer which is caused by GPCR activation without the need for fluorescent or luminescent labels

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13
Q

Target identificiation

A

Find a disease phenotype
Find drugs that interfere with the phenotype
Then find its specific protein targets

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14
Q

Target based vs phenotypic screening

A

Target based: Known molecular targets, high throughput, clear mechanism, biophysical lead confirmation and disease relevance risk
Molecular based; No knowledge of targets, lower throughput, unknown/multiple mechanisms, lead confirmation by cell assays and in vivo and disease relevant.

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15
Q

Examples of phenotypic screens

A

Cell=Thyrocytes Assay=TSH responsive proteins
Tumour cells or assay would be Cell viability (ATP content)

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16
Q

what is pluripotent cells

A

They can be differentiated into any cell type

17
Q

Chlorcyclizine

A

Repurposed for treating HCV infection.
CAG promoter has high levels of gene expression.
Therefore allows luciferase expression.

18
Q

MOA for chlorcyclizine

A

Targets E1
Prevents viral fusion of the lipid envelope at a low pH environment
Thus no release of the viral RNA into the cytosol.