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Clinicopathological Analysis of miRNA Expression in Breast Cancer Tissues by Using miRNA In Situ Hybridization
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MiR-489 regulates chemoresistance in breast cancer via epithelial mesenchymal transition pathway

Li Jiang1, Dongxu He2, Dantong Yang1

  • 1School of Pharmaceutical Sciences, Jiangnan University, 1800 Lihu Rd, Wuxi, Jiangsu 214122, China.

FEBS Letters
|May 3, 2014
PubMed

Insights

MicroRNA-489 (miR-489) suppresses chemoresistance and epithelial-mesenchymal transition (EMT) in breast cancer by targeting Smad3. Restoring miR-489 levels can reverse adriamycin resistance, offering therapeutic potential.

Area of Science:

  • Oncology
  • Molecular Biology
  • Genetics

Background:

  • Chemoresistance is a major challenge in breast cancer treatment.
  • Epithelial-mesenchymal transition (EMT) is linked to chemoresistance and metastasis.
  • MicroRNAs play critical roles in cancer development and drug response.

Purpose of the Study:

  • To investigate the role of microRNA-489 (miR-489) in adriamycin (ADM)-resistant breast cancer.
  • To explore the relationship between miR-489, chemoresistance, and EMT.
  • To identify the molecular targets of miR-489 involved in these processes.

Main Methods:

  • Analysis of miR-489 expression in adriamycin-resistant (MCF-7/ADM) and sensitive (MCF-7/WT) breast cancer cells.
  • Forced expression of miR-489 in MCF-7/ADM cells.
  • Identification of miR-489 targets using molecular assays.
  • Assessment of EMT markers and chemoresistance.
  • Validation in chemoresistant tumor xenografts and clinical samples.

Main Results:

  • MiR-489 was significantly downregulated in MCF-7/ADM cells.
  • Forced expression of miR-489 reversed adriamycin resistance in breast cancer cells.
  • Smad3 was identified as a direct target of miR-489 and was highly expressed in resistant cells.
  • MiR-489 inhibited Smad3 expression and Smad3-mediated EMT properties.
  • The miR-489/Smad3/EMT axis was confirmed in vivo and in clinical samples.

Conclusions:

  • MiR-489 plays a crucial role in overcoming chemoresistance and EMT in breast cancer.
  • Targeting the miR-489/Smad3 pathway presents a potential therapeutic strategy for chemoresistant breast cancer.
Keywords:
Breast cancerChemoresistanceEpithelial mesenchymal transitionmicroRNAs

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