Theme 2 Lecture 4 Brief History of Drug Discovery Flashcards
Describe the evolution of drug screening and lead discovery
The beginning was the discovery of penicillin, then receptor binding assays, recombinant DNA technology, HTS and MTS
Explain the evolution of classical in vitro and in vivo pharmacology.
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.
Identify key blockbuster drugs
Beta blockers
Histamine h2 antagonists
Beta 2 adrenoreceptors
5-HT receptors
Dopamine D2 receptor antagonists
CCBS
Explain molecular target-based screens
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
List examples of Screening Technologies
FLIPR-Ca2+
NanoBRET
Reporter Genes
Label Free
Intracellular Calcium
Fluo4AM detects changes in calcium levels in response to the GPCR activation
GPCR activation pathways calcium via subunits
Gq and Gi/o which modulates via Gβγ subunits.
What does BRET stand for?
Bioluminescence Resonance Energy Transfer
Explain how BRET works?
Uses N-terminal Nluc tag on the (GPCR)
Measures the energy transfer between NanoLuc and the fluorescent ligand.
Thus showing Ligand Binding
How do reporter genes work for cell signalling?
Reporter genes are luciferase and GFP.
These measure the transcriptional activity resulting from GPCR signalling.
What is DMR
Dynamic mass redistribution
Explain label free technologies
Monitors changes in the cell monolayer which is caused by GPCR activation without the need for fluorescent or luminescent labels
Target identificiation
Find a disease phenotype
Find drugs that interfere with the phenotype
Then find its specific protein targets
Target based vs phenotypic screening
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.
Examples of phenotypic screens
Cell=Thyrocytes Assay=TSH responsive proteins
Tumour cells or assay would be Cell viability (ATP content)