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MiR-221 promotes stemness of breast cancer cells by targeting DNMT3b

Giuseppina Roscigno1,2, Cristina Quintavalle1,2, Elvira Donnarumma3

  • 1Department of Molecular Medicine and Medical Biotechnology, "Federico II" University of Naples, Naples, Italy.

Oncotarget
|November 12, 2015
PubMed

Insights

MicroRNAs (miRs) regulate cancer stem cells (CSCs) in breast cancer. Upregulated miR-221 in CSCs promotes stemness by targeting DNMT3b, contributing to tumor growth.

Area of Science:

  • Oncology
  • Molecular Biology
  • Genetics

Background:

  • Cancer stem cells (CSCs) drive tumor heterogeneity and tumorigenesis.
  • MicroRNAs (miRs) are key regulators of normal and cancer stem cell self-renewal and differentiation.
  • The specific roles of miRs in human breast cancer stem cells (BCSCs) remain incompletely understood.

Purpose of the Study:

  • To investigate the functional role of miRs in human breast cancer stem cells (BCSCs).
  • To elucidate the molecular mechanisms by which miRs influence BCSCs and their stemness properties.

Main Methods:

  • Comparative analysis of miR-221 expression in BCSCs (mammospheres) versus differentiated cells.
  • Functional studies involving miR-221 transfection in T47D breast cancer cells.
  • Identification of miR-221 targets and investigation of their role in regulating stemness genes (e.g., Nanog, Oct 3/4) via DNA methylation.

Main Results:

  • miR-221 was significantly upregulated in BCSCs and mammospheres compared to differentiated cells.
  • Overexpression of miR-221 in T47D cells enhanced mammosphere formation and stem cell marker expression.
  • DNMT3b was identified as a target of miR-221; DNMT3b represses stemness genes through promoter methylation, partially counteracting miR-221's effects.

Conclusions:

  • miR-221 plays a crucial role in maintaining breast cancer stem cell stemness.
  • The miR-221/DNMT3b axis is a potential regulatory pathway contributing to breast cancer tumorigenicity.
  • Targeting miR-221 may offer a therapeutic strategy for breast cancer by modulating CSC properties.
Keywords:
DNMTbreast cancercancer stem cellsmicroRNAs

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