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Profiling of Estrogen-regulated MicroRNAs in Breast Cancer Cells
16:24

Profiling of Estrogen-regulated MicroRNAs in Breast Cancer Cells

Published on: February 21, 2014

Regulatory interplay between miR-21, JAG1 and 17beta-estradiol (E2) in breast cancer cells

S Duygu Selcuklu1, Mark T A Donoghue, Michael J Kerin

  • 1Genetics and Biotechnology Lab, Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Ireland.

Biochemical and Biophysical Research Communications
|May 24, 2012
PubMed

Insights

MicroRNA-21 (miR-21) directly targets Jagged-1 (JAG1), impacting breast cancer progression. Estrogen influences this interaction, revealing a complex regulatory network in different breast cancer subtypes.

Area of Science:

  • Molecular Biology
  • Oncology
  • Genetics

Background:

  • Overexpression of the oncomir miR-21 is linked to various cancers, including breast cancer.
  • Elevated Jagged-1 (JAG1) levels are implicated in estrogen receptor-negative (ER-) breast cancer, and JAG1 is a predicted target of miR-21.

Purpose of the Study:

  • To investigate the regulatory relationship between miR-21 and JAG1 in different breast cancer subtypes.
  • To elucidate the role of 17beta-estradiol (E2) in modulating the miR-21/JAG1 interaction.

Main Methods:

  • Demonstrated direct targeting of JAG1 by miR-21 via ablation of the miR-21 binding site in the JAG1 3'UTR in MCF-7 (ER+) cells.
  • Assessed miR-21 targeting of JAG1 in MDA-MB-231 (ER-) cells, noting its dependence on miR-21 dosage.
  • Analyzed the correlation between miR-21 and JAG1 expression levels and the effect of E2 on JAG1 levels.

Main Results:

  • miR-21 directly targets and represses JAG1 in ER+ breast cancer cells (MCF-7).
  • miR-21 targeting of JAG1 in ER- breast cancer cells (MDA-MB-231) is dosage-dependent.
  • miR-21 and JAG1 expression levels were negatively correlated in both cell lines.
  • 17beta-estradiol (E2) increases JAG1 levels by downregulating miR-21, thereby reducing miR-21's repressive effect on the JAG1 3'UTR.

Conclusions:

  • A regulatory interplay exists between miR-21, JAG1, and E2 in breast cancer.
  • This interaction is crucial for understanding the oncogenic roles of miR-21 and JAG1 in distinct breast cancer subtypes.
  • Findings contribute to understanding breast cancer pathogenesis and potential therapeutic targets.

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