Microarray-based screening of heat shock protein inhibitors

Area of Science:

• Biochemistry
• Molecular Biology
• Drug Discovery

Background:

• Heat shock proteins (HSPs) are crucial in diseases including cancer, Alzheimer's, and malaria.
• Current methods for identifying HSP inhibitors are protein-intensive and require microplate formats.
• There is a need for more efficient and less protein-consuming assays to discover HSP inhibitors.

Purpose of the Study:

• To develop a miniaturized, multiplexed protein microarray assay for identifying novel HSP inhibitors.
• To enable parallel analysis of different ATP-binding proteins on a single microarray.
• To reduce the amount of protein required for inhibitor screening.

Main Methods:

• Developed a miniaturized protein microarray assay utilizing competitive binding.
• Used fluorescence-labeled ATP and potential inhibitors binding to the HSP ATP-binding site.
• Demonstrated multiplexing by immobilizing human HSP90α and Helicobacter pylori HtpG on microarrays.

Main Results:

• The assay successfully identified novel geldanamycin/reblastatin derivatives as HSP inhibitors.
• Achieved IC50 values in the range of 0.5 nM to 4 μM.
• Reported Z(*)-factors between 0.60 and 0.96, indicating assay robustness.
• Enabled analysis with as little as 300 pmol of protein.

Conclusions:

• The developed protein microarray is a powerful tool for discovering novel inhibitors of HSPs.
• The assay's miniaturized and multiplexed nature offers significant advantages over traditional methods.
• This technology holds potential for identifying inhibitors targeting various members of the HSP90 family.