Mechanistic toxicology is the study of how chemical or physical agents interact with living organisms to cause toxicity. At Sygnature Discovery, our teams in Bioscience, DMPK and Discovery Toxicology combine efforts to unravel the mechanisms of toxicity of drug candidates to prevent toxicity and design more desirable chemicals.
Why do we want to understand the mechanisms of toxicity?
Mechanistic knowledge is useful for the design of new drugs. If the mechanism of toxicity is understood, descriptive toxicology becomes useful in predicting the toxic effects of related chemicals.
At Sygnature Discovery we have developed and validated techniques for studying and identifying the mechanisms of toxicity during the discovery optimisation process.
Using cutting-edge technologies, we can identify and understand the cellular, biochemical and molecular basis by which chemicals exert toxic effects. An in-depth understanding of these mechanisms will enable us to better monitor and build SAR to re-engineer the lead molecules and subsequently overcome specific toxic liabilities.
Early assessment of cellular toxicity responses enables our team to create safer candidates that significantly increases the chance of clinical progression in drug discovery. This is reflected in our excellent track record of delivering candidates that progress to human dosing.
Six major types of mechanistic assays:
- Cell viability
- Mitochondrial damage
- Nuclear DNA Fragmentation
- Protein adducts (reactive metabolites)
- Custom toxicology – flexible service where we can propose use of different cell lines, endpoints and time points to address particular customer concerns.
As part of our panel of mechanistic toxicity assessment we offer the following capabilities:
- Mitochondrial toxicity (glu/gal or Mitotox Glo) – compares cytotoxicity using cells grown in glucose and galactose media to determine mitochondrial impairment; or alternatively we can determine oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) using the Seahorse Xfp extracellular flux analyser to assess cellular bioenergetics and potential mechanisms of mitochondrial toxicity.
- Reactive metabolite assessment – uses LC-MS/MS detection to identify glutathione or cyanide adducts in trapping studies whilst incubating drug with human liver microsomes.
- Cell viability – general cell viability assessment using Resazurin.
- Phospholipidosis – assesses the accumulation of intracellular phospholipids in tissues, via excessive lysosomal storage, in response to the drug candidate.
- Steatosis – assessing the drug-induced accumulation of triglycerides/lipids within the liver cells.
- Lysosomal trapping – investigates the accumulation of the drug in the lysosomes.
- Toxicological gene regulation – using qRT-PCR to measure toxicologically relevant changes in gene expression. Alternatively, cost-effective options using reporter-gene assays are also available.
Mechanistic biomarkers are released into circulation and reflect events at the molecular level.
A number of cell lines are available in 2D, 3D and spheroid cultures to help us identify pinpoint the mechanisms of toxicity. 3D models and spheroids, in particular, offer the possibility to carry out long-term repeat dose studies which are not possible using 2D systems. Also, 3D cellular models closely mimic native tissues and have the benefit of cell to cell interaction making them the ideal model to best identify and understand the molecular basis by which chemicals exert toxic effects.
This level of expertise in tissue culture is complemented with high content imaging platforms (e.g. ImageXpress®, IncuCyte® ) as well as modern molecular (e.g. qRT-PCR) and biochemical techniques (e.g. AlphaLISA).
We are also equipped with state-of-the-art high-resolution accurate mass spectrometry capabilities. Such instruments provide increased sensitivity and enhanced structural characterisation. Sygnature’s metabolite identification team can access either the Sciex QTRAP® 5500 or the Waters Xevo® G2-S QTof to determine high-resolution accurate mass of any metabolites.