Original Article

Staphylococcus epidermidis modulates EMT-related gene expression and viability in MDA-MB-231 breast cancer cells

Abstract

Background and Objectives: Breast tissue microbiota differs between healthy and cancerous tissues, with some bacteria influencing tumor progression. Staphylococcus epidermidis, a common skin commensal found in breast tumors, may play a role in epithelial-mesenchymal transition (EMT), a key step in metastasis. This study evaluated the effects of S. epidermidis culture and cell-free supernatant (CFS) on MDA-MB-231 breast cancer cell survival and expression of EMT-related genes Snail1, fibronectin 1 (FN1), and N-cadherin (CDH2).
Materials and Methods: Different concentrations of S. epidermidis cultures and their CFS were applied to MDA-MB-231 cells. Cytotoxic effects were assessed by MTT assay at 2, 4, and 24 hours post-treatment. Real-time PCR analyzed gene expression after 24 hours of exposure to non-toxic concentrations (MOI 50 and 100 for cultures; 14% for CFS).
Results: Low concentrations did not affect viability, while higher doses (MOI 100 and 14% CFS) reduced viability by up to 60% and 90%, respectively, at 24 hours. MOI 50 did not significantly alter gene expression. At MOI 100, Snail1 and FN1 were significantly upregulated, but CDH2 was unchanged. Treatment with 5% and 7% CFS significantly increased all three EMT gene expressions, indicating EMT induction.
Conclusion: S. epidermidis affects EMT gene expression and cell viability, indicating potential involvement in breast cancer progression.

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IssueVol 17 No 5 (2025) QRcode
SectionOriginal Article(s)
DOI https://doi.org/10.18502/ijm.v17i5.19887
Keywords
Staphylococcus epidermidis Epithelial-mesenchymal transition Breast neoplasms Gene expression Microbiota
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Creative Commons License This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
How to Cite
1.
Zarei Mahmoodabadi F, Tabatabaee Bafroee A, Moshiri A, Siadat SD, Ebrahimzadeh N. Staphylococcus epidermidis modulates EMT-related gene expression and viability in MDA-MB-231 breast cancer cells. Iran J Microbiol. 2025;17(5):783-790.