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Updated: Jun 24, 2026
High-throughput Screening for Chemical Modulators of Post-transcriptionally Regulated Genes
Published on: March 3, 2015
Novel high-throughput screening system for identifying STAT3-SH2 antagonists
Yutaka Uehara1, Masato Mochizuki, Kenji Matsuno
1Center for Drug Discovery, Graduate School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
Abstract:
Constitutive activation of the oncogenic transcription factor STAT3 frequently occurs in various human malignancies. STAT3 activation involves dimerization via intermolecular pTyr-SH2 interaction. Thus, antagonizing this interaction is a feasible approach to inhibit STAT3 activation for cancer therapy. In order to identify selective STAT3 inhibitors, we developed a biochemical HTS system based on AlphaScreen technology, which measures the abilities of test compounds to antagonize pTyr-SH2 interactions. We screened our chemical libraries using this system and identified 5,15-diphenylporphyrin (5,15-DPP) as a selective STAT3-SH2 antagonist. Selective inhibition of STAT3 nuclear translocation and DNA biding activity was observed in cells treated with 5,15-DPP. IL-6-dependent dimerization of STAT3, c-myc promoter binding and c-myc protein expression were all suppressed by 5,15-DPP, whereas no decrement in either expression or phosphorylation level of STAT3 was observed. Thus, the HTS assay system represented herein may be useful for identifying novel STAT3-SH2 antagonists.
Insights
Researchers identified 5,15-diphenylporphyrin (5,15-DPP) as a selective STAT3-SH2 antagonist. This compound inhibits STAT3 dimerization and downstream effects, offering a potential cancer therapy approach.
Area of Science:
- Oncology
- Molecular Biology
- Biochemistry
Background:
- Constitutive activation of Signal Transducer and Activator of Transcription 3 (STAT3) is common in human cancers.
- STAT3 activation relies on dimerization through a pTyr-SH2 interaction, making it a therapeutic target.
- Inhibiting this interaction is a promising strategy for cancer treatment.
Purpose of the Study:
- To develop a high-throughput screening (HTS) system to identify selective STAT3 inhibitors.
- To find novel compounds that antagonize the STAT3 pTyr-SH2 interaction.
Main Methods:
- Developed a biochemical HTS assay utilizing AlphaScreen technology.
- Screened chemical libraries to identify STAT3-SH2 antagonists.
- Assessed the effects of identified compounds on STAT3 activity in cellular models.
Main Results:
- Identified 5,15-diphenylporphyrin (5,15-DPP) as a selective STAT3-SH2 antagonist.
- Demonstrated that 5,15-DPP selectively inhibits STAT3 nuclear translocation and DNA binding.
- Observed suppression of IL-6-dependent STAT3 dimerization, c-myc promoter binding, and c-myc protein expression by 5,15-DPP.
Conclusions:
- The developed HTS system is effective for identifying STAT3-SH2 antagonists.
- 5,15-DPP is a potent inhibitor of STAT3 signaling pathways crucial for cancer cell proliferation.
- This study provides a novel therapeutic lead for targeting STAT3-driven malignancies.
