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Updated: Jul 13, 2026

Optimization of a Multiplex RNA-based Expression Assay Using Breast Cancer Archival Material
11:12

Optimization of a Multiplex RNA-based Expression Assay Using Breast Cancer Archival Material

Published on: August 1, 2018

The E2F-regulated gene Chk1 is highly expressed in triple-negative estrogen receptor /progesterone receptor /HER-2

Lieve Verlinden1, Isabelle Vanden Bempt, Guy Eelen

  • 1Laboratorium voor Experimentele Geneeskunde en Endocrinologie and CMPG/ESAT, Katholieke Universiteit Leuven, Gasthuisberg, Herestraat 49, 3000 Leuven, Belgium.

Cancer Research
|July 20, 2007
PubMed

Insights

Checkpoint kinase 1 (Chk1) and Claspin expression is linked to aggressive breast cancer. Their levels were highest in high-grade, triple-negative tumors, suggesting potential therapeutic targets.

Area of Science:

  • Molecular Biology
  • Cancer Research
  • Cell Cycle Regulation

Background:

  • Checkpoint kinase 1 (Chk1) and Claspin are DNA-damage checkpoint proteins previously shown to be downregulated by 1,25-dihydroxyvitamin D(3).
  • 1,25-dihydroxyvitamin D(3) is a known inhibitor of cell proliferation.

Purpose of the Study:

  • To investigate the transcriptional regulation of Chk1 and Claspin.
  • To determine the expression levels of Chk1 and Claspin in human breast cancer tissue.
  • To correlate Chk1, Claspin, and E2F1 expression with clinicopathologic variables in breast cancer.

Main Methods:

  • Transient transfection experiments in MCF-7 breast cancer cells to assess promoter activity.
  • Quantitative reverse transcriptase-PCR analysis of Chk1, Claspin, and E2F1 transcript levels in 103 primary invasive breast carcinomas.
  • Comparison of transcript levels with clinicopathologic variables including histologic grade, estrogen receptor (ER), progesterone receptor (PR), and HER2 status.

Main Results:

  • Promoter activities of Chk1 and Claspin were regulated by E2F family transcription factors.
  • Strong correlation observed between Chk1 and Claspin transcript levels.
  • Transcript levels of Chk1, Claspin, and E2F1 were highest in histologic grade 3 tumors and in ER/PR-negative tumors.
  • Chk1 expression was significantly elevated in grade 3 triple-negative (ER-/PR-/HER-2-) breast carcinomas.

Conclusions:

  • E2F transcription factors regulate Chk1 and Claspin.
  • Chk1 and Claspin expression levels correlate with aggressive breast cancer subtypes, including triple-negative breast cancer.
  • Further research into Chk1 inhibitors for triple-negative breast carcinomas is warranted due to limited treatment options.

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