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Eriocalyxin B Inhibits STAT3 Signaling by Covalently Targeting STAT3 and Blocking Phosphorylation and Activation of

Xiaokui Yu1, Li He1, Peng Cao2

  • 1Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.

Plos One
|May 27, 2015
PubMed

Insights

Eriocalyxin B, a compound from traditional Chinese medicine, directly inhibits Signal Transducer and Activator of Transcription 3 (STAT3) activation. This targeted approach induces apoptosis in STAT3-dependent cancer cells, offering a novel therapeutic strategy.

Area of Science:

  • Oncology
  • Pharmacology
  • Molecular Biology

Background:

  • Signal Transducer and Activator of Transcription 3 (STAT3) is crucial in cancer development, promoting cell growth and survival.
  • Targeting STAT3 is a promising strategy for cancer treatment due to its role in oncogenesis.

Purpose of the Study:

  • To identify novel STAT3 inhibitors from a traditional Chinese herb medicine library.
  • To investigate the mechanism of action of Eriocalyxin B (EB) as a STAT3 inhibitor.

Main Methods:

  • Screening of a traditional Chinese herb medicine compound library.
  • In vitro assays to assess STAT3 phosphorylation inhibition and apoptosis induction.
  • Site-directed mutagenesis and LC/MS/MS analysis to identify the interaction site.
  • Computational modeling to confirm direct interaction.

Main Results:

  • Eriocalyxin B (EB) was identified as a specific inhibitor of STAT3.
  • EB selectively inhibited STAT3 phosphorylation and induced apoptosis in STAT3-dependent tumor cells.
  • EB covalently binds to Cys712 of STAT3, a thiol-mediated interaction, to inhibit its activation.

Conclusions:

  • Eriocalyxin B directly targets and covalently modifies STAT3 at Cys712, leading to its inactivation.
  • EB demonstrates potential as a novel therapeutic agent for STAT3-dependent cancers.
  • The findings highlight the therapeutic value of traditional Chinese medicine compounds in cancer therapy.

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