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Regulation of KLF4 by posttranslational modification circuitry in endocrine resistance

Zhuan Zhou1, Xinxin Song1, Junlong Jack Chi2

  • 1Department of Obstetrics and Gynecology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States.

Cellular Signalling
|February 22, 2020
PubMed

Insights

Krüppel-like factor 4 (KLF4) drives endocrine resistance in breast cancer by coordinating estrogen receptor signaling. Targeting the Src-VHL-KLF4 pathway can re-sensitize resistant tumors to tamoxifen.

Area of Science:

  • Oncology
  • Molecular Biology
  • Cell Biology

Background:

  • Krüppel-like factor 4 (KLF4) is crucial for cellular events and implicated in cancers like breast cancer.
  • Posttranslational modifications regulate KLF4 activity, impacting its role in disease.
  • KLF4 deregulation is linked to poor prognosis and treatment resistance.

Purpose of the Study:

  • To investigate the role of KLF4 in estrogen receptor signaling and endocrine resistance in breast cancer.
  • To elucidate the molecular mechanisms by which KLF4 influences response to endocrine therapy.
  • To identify potential therapeutic targets for overcoming tamoxifen resistance.

Main Methods:

  • Immunohistochemistry (IHC) analysis of human breast cancer specimens.
  • Drug screening to identify modulators of KLF4 protein expression.
  • Biochemical assays to study protein interactions and modifications (phosphorylation, ubiquitylation).

Main Results:

  • KLF4 protein accumulates in ER-positive breast cancer tissues and correlates with poor prognosis and endocrine resistance.
  • Src kinase activity and VHL (von Hippel-Lindau tumor suppressor) ubiquitylation regulate KLF4 levels and tamoxifen resistance.
  • Phosphorylation of VHL by Src enhances KLF4-mediated endocrine resistance.
  • Targeting the Src-VHL-KLF4 axis with inhibitors or peptides re-sensitizes resistant cells.

Conclusions:

  • KLF4 plays a novel role in mediating endocrine resistance in breast cancer.
  • The Src-VHL-KLF4 signaling axis is a critical regulator of tamoxifen resistance.
  • Interventions targeting this pathway hold promise for treating endocrine-resistant breast cancer.
Keywords:
EndocrineKLF4ResistanceSrcVHL

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