In vitro cell-based assay: A comprehensive tool for drug development
In vitro cell-based assays are a type of analytical test that utilises reagents to generate a detectable signal that can be used to determine the size of a biological process.
In comparison to non-cell-based, biochemical assays, cell-based assays are thought to be more biologically relevant agents to anticipate the complexity of treatment response in a biological system. Cell-based assays speed up and improve drug development, enabling the speedy and effective commercialization of therapeutics.
Using cell-based assays, it is possible to:
- Studying drug efficacy
- Toxicology studies, in vitro ADME
- Drug candidate selection
- Selection of drugs
In addition, they can be used to evaluate pharmacological biomarkers, identify individuals who might respond to medication and evaluate immunogenicity. The assessment of target interaction, the identification of safety markers, and the observation of resistant strains all require the use of cell-based assays. A wide range of functional and physiochemical effects are also evaluated using cell-based assays, including viability, proliferation, cytotoxicity, apoptosis, signal transduction, enzyme activity and gene activity.
Selecting the Right Cell-based Assay
A variety of considerations, including the experiment’s objectives and current stage, must be taken into account when selecting a pertinent in vitro cellular-based assay at the right time on the protracted path to biopharmaceutical drug development and authorization. The creation of a biologically active assay that will produce high-quality data will be motivated by a clear knowledge of the environment of use for the assays and how the data will be employed to play a proactive role.
Implications for Developing Cell-Based Assays
Building the most pertinent, repeatable, and reliable test follows the determination of the cell-based assay’s purpose and context of use. To demonstrate that the assay is biologically relevant, it must incorporate some part of the drug’s MOA. Finding a biologically appropriate cell line, either primary or immortalised, that will highlight at least one or more components of the treatments’ MOA is necessary for this, as is choosing an acceptable endpoint to test.
Endpoints in the mechanism of action
There are benefits and drawbacks to both early and late endpoints. In contrast to later endpoints (cell proliferation/cytotoxicity assays), which involve so many hours or days of culturing to establish a signal, early assay endpoints (receptor binding), which produce a detectable signal quickly, have advantages because they are more advantageous and have a lower risk of artefacts caused by assay chemistry and matrix interference problems.
When selecting an assay, it is important to take into account the amount of time needed for reagent production, the overall amount of time needed to create a signal from the assay chemistry, and the signal’s stability. A consistent signal offers benefits including ease of data capture and flexibility, as well as minimising differences while processing large numbers of plates.
Optimizing Assays
Numerous subtle parameters, including the growth media, biological matrix, surface-to-volume ratios, and gas exchange, might affect how sensitive an assay is to test drugs. At various points in a bioassay’s life cycle, the use of a combinatorial, statistical design of experiments (DOE) technique can be used successfully to define, optimise, and verify the assays with the additional benefit of resource utilization.
A suitable bioassay can be developed and validated with the help of this method, which effectively and methodically modifies the factors of interest to identify the important assay parameters, effectively comprehend the implications of each individual factor as well as projected interactions between various factors to the impact on the system response.
In vitro cell-based assays in the Future
In contrast to biochemical tests, which are carried out in a biological environment that can imitate pathological conditions, maintain signalling pathways, and simulate drug responses, cell-based assays offer a complex and more medically and biologically realistic assay system.
Despite the fact that primary cells are more biologically important, they are also more unpredictable, which makes it more challenging to produce a reliable cell-based assay. A single cell-based experiment would not be able to adequately resolve the phenotypical impacts of treatment of interest on the cell because these effects may combine.
Amidst these difficulties, cell-based assays are essential to the drug development process. Numerous technologies are being used to get around the current restrictions, including genome-editing tools like CRISPR/Cas9 to make it simple to engineer mutations, knock-outs or knock-ins of a specific reporter or marker at precise locations on the genome, 3D culture models, co-culture of cells, and artificial tissue techniques to resemble real biological environments and provide accurate results.
