Combination of Doxorubicin and Berberine Generated Synergistic Anticancer Effect on Breast Cancer Cells Through Down-regulation of Nanog and miRNA-21 Gene Expression

Background: Our purpose was to investigate the effect of berberine (BER) and doxorubicin (DOX) on the expression of stem cell markers Nanog and microRNA- 21 in MCF-7 cells. Methods: The study was an in vitro study employing the human breast cancer cell line MCF-7 that was divided into four groups: Group I: MCF-7 cell line maintained in drug-free environment as untreated control, Group II: MCF-7 cell line treated with different concentrations of DOX, Group III: MCF-7 cell line treated with various concentrations of BER. Group IV: MCF-7 cell line treated with different concentrations of combined DOX and BER. MTT assay determined the metabolic activity and viability of MCF-7 cells for all groups. We further extracted total RNA from MCF-7 cells, and RT-PCR assayed the expression of Nanog and miRNA-21. Results: The results revealed that DOX and/or BER decreased the percentage of viable MCF-7 monolayer and mammospheres breast cancer cells in a concentrationdependent manner. Moreover, the combination of DOX and BER generated synergistic anticancer effect on MCF-7 monolayer cells and mammospheres. In addition, DOX alone, BER alone, and their combination significantly reduced Nanog and miRNA- 21 gene expression in MCF-7 mammospheres compared with untreated mammospheres. Conclusions: BER may affect the viability of breast cancer cells through downregulation of Nanog and miRNA-21 gene expression, ultimately enhancing the sensitivity of breast cancer cell line to DOX. BER may be an effective chemotherapeutic agent against breast cancer where the combination of DOX and BER generates synergistic anticancer effects.