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Suppression of SIN3A by miR-183 Promotes Breast Cancer Metastasis

Mackenzie L Davenport1, Mara R Davis1, Baylea N Davenport1

  • 1Department of Genetics, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama.

Molecular Cancer Research : MCR
|March 5, 2022
PubMed

Insights

SWI-independent-3 (SIN3A) is a metastasis suppressor gene. Its decreased expression in breast cancer, driven by miR-183, promotes tumor cell invasion and metastasis, impacting patient survival.

Area of Science:

  • Oncology
  • Molecular Biology
  • Gene Regulation

Background:

  • SWI-independent-3 (SIN3) chromatin modification complexes are implicated in cancer progression.
  • SIN3A knockdown enhances human breast cancer cell invasion and metastasis.
  • SIN3A expression levels in patient breast carcinoma were previously unknown.

Purpose of the Study:

  • To investigate SIN3A expression in human breast carcinoma tissues.
  • To determine the role of microRNA (miRNA) in regulating SIN3A expression.
  • To elucidate the functional impact of the miR-183/SIN3A axis on breast cancer metastasis and patient survival.

Main Methods:

  • Analysis of SIN3A mRNA and protein levels in patient breast carcinoma and normal breast tissues.
  • In vitro studies using breast carcinoma cell lines to assess the effect of ectopic miR-183 on SIN3A expression.
  • In vivo metastasis assays following ectopic miR-183 expression.
  • Correlation analysis between miR-183/SIN3A levels and patient survival data.

Main Results:

  • SIN3A expression is significantly lower in breast carcinoma compared to normal breast tissue.
  • Ectopic miR-183 reduces SIN3A levels in breast carcinoma cell lines.
  • miR-183 promotes breast cancer cell migration and invasion in a SIN3A-dependent manner.
  • Ectopic miR-183 enhances metastasis in vivo.
  • High miR-183 and low SIN3A levels correlate with shorter overall survival in breast cancer patients.

Conclusions:

  • SIN3A functions as a metastasis suppressor gene in human breast cancer.
  • Aberrant expression of SIN3A in breast cancer is partly due to suppression by miR-183.
  • The miR-183-mediated suppression of SIN3A is a key mechanism promoting breast cancer metastasis and reduced patient survival.

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