Phenotype-Based Drug Screening

Drug discovery based on target molecules may represent the primary focus of the pharmaceutical industry. The existence of compensation mechanisms and feedback pathways in the complex cellular environment usually leads to a significant reduction in the targeting and therapeutic efficacy of the drugs, even though the drug has been previously demonstrated to be effective at the molecular level in vitro. The discovery of phenotypic drugs initially requires the identification of disease-specific features. Cell phenotypic screening has regained momentum and is receiving widespread attention.

Due to advances in both high-throughput phenotypic assay techniques and target identification methodologies, cell phenotype has been emerging as an attractive approach for screening and profiling drugs in native cells. They could provide rich information, real-time kinetics, flexible assays and high throughput in screening that are common to all phenotypic assays. Single-cell measures have been used to phenotype individual cells within tissues in each experiment. However, the field is moving toward multimodal measurements from the same cell to enhance feature quantifications and give a richer picture of a cell's phenotype at any given moment.

The Advantages of Phenotype-Based Drug Screening

1. Phenotype-based drug screening is a preclinical strategy in drug discovery. It evaluates observable phenotypic changes in a cell, tissue or an entire organism. The phenotypical changes could be used to identify molecules and modulators for a disease or disorder in vitro or in vivo. The goal is to identify compounds that ameliorates the disease phenotype without necessarily knowing the target or mechanism. Such screening has been successfully performed for identifying leads selectively killing cancer cells or alleviating various disorders. This approach allows new targets and signaling pathways to be identified and, most importantly, decreases false-positive hits.
2. As the entire cell/tissue or organism's physiology is taken into account, various parameters, such as tissue cross talk, absorption, distribution, metabolism, elimination (ADME) parameters and macro-environmental influences synergistically participate in the lead identification. Such an approach ensures that the identified hit is physiologically relevant, with a high potential for clinical translation.
3. Phenotype-based drug screening focuses on alleviating the condition without initially considering the target or mechanism of action by assuming the disorder as a whole. Therefore, new or multiple targets or mechanisms can be identified through this approach, making it highly desirable not only for new drug discovery but also for drug repurposing programs. The advancement in the screening models has ensured this method as a serious approach in drug discovery.

Cell phenotype analysis plays a major role in promoting drug discovery and development. As a screening method to assess the biological activity of compounds based on cell or organism level, phenotypic screening could shorten the period of drug discovery of disease. Phenotype-based drug screening programs involve endpoints of using simple cytotoxicity-based screens, coculture and organoids to animal model, making it a very flexible and robust setup. Advances in imaging, analysis software and target techniques offer a strong reason for selecting this approach in drug discovery programs.

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• High Throughput Screening Services
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