Biochemistry and Cell Biology Summary

High-throughput screening (HTS) has not delivered well on its initial promise of a stream of new drugs significantly based on the use of robotic systems that allow an operator to carry out hundreds of thousands of assays in a few days. A major reason for the unfulfilled promise is that the emphasis on robotics has been rewarded by a tremendous increase in the capacity to do a large number of experiments. However, in order for new drugs to be discovered, the robotics needs to be coupled with increases and improvements in the quality of the data generated and in interpreting the data in the most informative manner.

In keeping with the old adage applied to computers, "garbage in, garbage out", if a screening assay is poorly designed, the chances of getting valuable information in the form of useable lead compounds from the screen are poor. Add to the problems an incorrect or poorly defined assay characterization and the poor results in HTS are no longer surprising.

The changes needed in the drug development process include a better understanding of the underlying biochemistry and/or cell biology of a potential drug target. From such a foundation, a better screening assay can be designed and insightful interpretation and secondary and tertiary compound selection procedures will improve substantially. PharmOptima can help in these critical design and interpretation processes by offering the following services:

We offer both consultation services and laboratory implementation in:

• Assay design for biochemistry and cell biology using radioactive and fluorescent probes
• Investigation of kinetics for biochemical and cellular processes with emphasis on developing an assay well-suited to HTS
• Optimization of hit selection from HTS using kinetic and statistical principles, not just an arbitrary line drawn across HTS data
• Dose-response analyses well beyond the usual IC50 determination
• Design and implementation of secondary assays in order to convert hits to leads with a high probability of the leads proving effective in later stages of drug development

Frequently asked questions about Biochemistry and Cell Biology in the Drug Discovery Pathway

1. What information and experiments are most useful for setting up the best assay for HTS and lead selection? 
2. What can and should be known about the time-course of the biochemistry or cell biology being measured?
3. What happens if the wrong time in the time-course is chosen as the measurement for screening or characterization?
4. How should a cut-off be selected from determining "hits" from screening data?  Are there statistical methods with more promise and rigor than an arbitrary percent cut-off or the conventional "three standard deviations from the mean"?
5. Why are low potency "hits" often poorly reproducible or frequently not verified on retesting?
6. In screening, what are the benefits and hazards of cell assays in contrast to assays based on isolated proteins or other isolated cell constituents, such as enzymes and receptors?  What is the relationship between "high content" screening and cell-based assays?