Document Type
Article
Language
eng
Publication Date
5-31-2017
Publisher
Springer
Source Publication
BMC Biochemistry
Source ISSN
1471-2091
Abstract
Background
Protein tyrosine phosphatases (PTPs) like dual specificity phosphatase 5 (DUSP5) and protein tyrosine phosphatase 1B (PTP1B) are drug targets for diseases that include cancer, diabetes, and vascular disorders such as hemangiomas. The PTPs are also known to be notoriously difficult targets for designing inihibitors [sic] that become viable drug leads. Therefore, the pipeline for approved drugs in this class is minimal. Furthermore, drug screening for targets like PTPs often produce false positive and false negative results.
Results
Studies presented herein provide important insights into: (a) how to detect such artifacts, (b) the importance of compound re-synthesis and verification, and (c) how in situ chemical reactivity of compounds, when diagnosed and characterized, can actually lead to serendipitous discovery of valuable new lead molecules. Initial docking of compounds from the National Cancer Institute (NCI), followed by experimental testing in enzyme inhibition assays, identified an inhibitor of DUSP5. Subsequent control experiments revealed that this compound demonstrated time-dependent inhibition, and also a time-dependent change in color of the inhibitor that correlated with potency of inhibition. In addition, the compound activity varied depending on vendor source. We hypothesized, and then confirmed by synthesis of the compound, that the actual inhibitor of DUSP5 was a dimeric form of the original inhibitor compound, formed upon exposure to light and oxygen. This compound has an IC50 of 36 μM for DUSP5, and is a competitive inhibitor. Testing against PTP1B, for selectivity, demonstrated the dimeric compound was actually a more potent inhibitor of PTP1B, with an IC50 of 2.1 μM. The compound, an azo-bridged dimer of sulfonated naphthol rings, resembles previously reported PTP inhibitors, but with 18-fold selectivity for PTP1B versus DUSP5.
Conclusion
We report the identification of a potent PTP1B inhibitor that was initially identified in a screen for DUSP5, implying common mechanism of inhibitory action for these scaffolds.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Bongard, Robert D.; Lepley, Michael; Thakur, Khushabu; Talipov, Marat R.; Nayak, Jaladhi; Jones Lipinski, Rachel A.; Bohl, Chris; Sweeney, Noreena; Ramchandran, Ramani; Rathore, Rajendra; and Sem, Daniel S., "Serendipitous Discovery of Light-Induced (In Situ) Formation of An Azo-Bridged Dimeric Sulfonated Naphthol as a Potent PTP1B Inhibito" (2017). Chemistry Faculty Research and Publications. 883.
https://epublications.marquette.edu/chem_fac/883
Comments
Published version. BMC Biochemistry, Vol. 18, No. 10 (May 31, 2017). DOI. © 2017 The Author(s).
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