br Breast cancer br Epithelial mesenchymal transition br

Breast cancer
Epithelial-mesenchymal transition
Breast cancer stem-like cells
Metastasis
Mammospheres 
Background: Curcumin is a polyphenolic compound with potent chemopreventive and anti-cancer efficacy. Purpose: To explore the potential anti-metastasis efficacy of curcumin in breast cancer stem-like CT99021 (BCSCs), which are increasingly considered to be the origin of the recurrence and metastasis of breast cancer. Methods: A CCK8 assay was performed to evaluate cell viability, and a colony formation assay was conducted to determine cell proliferation in MCF-7 and MDA-MB-231 adherent cells. Transwell and wound healing assays were used to detect the effect of curcumin on cell migration and invasion in MDA-MB-231 cells. Mammospheres were cultured with serum free medium (SFM) for three generations and the BCSC surface marker CD44+CD24−/low subpopulation was measured by flow cytometry. Mammosphere formation and differentiation abilities were determined after cell treatment with curcumin. Then, a reverse transcription-quantitative poly-merase chain reaction assay was conducted to detect the relative mRNA level of epithelial-mesenchymal tran-sition (EMT) marker genes and western blot analysis was performed to determine the protein expression of stem cell genes in mammospheres treated with curcumin.
Results: Curcumin exhibited anti-proliferative and colony formation inhibiting activities in both the MCF-7 and MDA-MB-231 cell lines. It also suppressed the migration and invasion of MDA-MB-231 cells. The CD44 +CD24−/low subpopulation was larger in mammospheres when MCF-7 and MDA-MB-231 adherent cells were cultured with SFM. Further studies revealed that curcumin inhibited mammosphere formation and dif-ferentiation abilities. Moreover, curcumin down-regulated the mRNA expression of Vimentin, Fibronectin, and β-catenin, and up-regulated E-cadherin mRNA expression levels. Western blot analysis demonstrated that cur-cumin decreased the protein expression of stem cell genes including Oct4, Nanog and Sox2.
Conclusion: The results of the present study suggest that the inhibitor effects of curcumin on breast cancer cells may be related to resistance to cancer stem-like characters and the EMT process. These data indicate that cur-cumin could function as a type of anti-metastasis agent for breast cancer.
Introduction accounting for over 8 million deaths every year. Breast cancer is
Cancer is the second leading cause of human mortality worldwide, thought to account for ∼30% of all estimated new cancer cases and
14% of estimated cancer deaths among women in the United States
Abbreviations: AML, acute myeloid leukemia; ATCC, American type culture collection; BCA, bicinchoninic acid; BCSCs, breast cancer stem-like cells; bFGF, basic fibroblast growth factor; CCK8, cell counting Kit-8; CSCs, cancer stem cells; DMEM, Dulbecco's modified eagle's medium; DMSO, dimethyl sulfoxide; EDTA, ethylene diamine tetraacetic acid; EGF, epidermal growth factor; EMT, epithelial-mesenchymal transition; FBS, fetal bovine serum; FCM, flow cytometry; FITC, fluorescein isothiocyanate; PBS, phosphate buffer saline; PE, phycoerythrin; PMSF, phenylmethylsulfonyl fluoride; PVDF, polyvinylidene difluoride; RIPA, radio-immunoprecipitation assay; RT-qPCR, reverse transcription-quantitative polymerase chain reaction; SDS-PAGE, sodium dodecyl sulfate polyacrylamide gel elec-trophoresis; SFM, serum free medium; SSM, serum-supplemented medium; TBST, tris-buffered saline tween-20
Corresponding authors.
E-mail addresses: Zhangfengxue@gzucm.edu.cn (F. Zhang), Hongqiwang@gzucm.edu.cn (H. Wang).
1 Co first author, contributed equally.
(Siegel et al., 2018). Breast cancer remains the most prevalent and fatal malignant tumor and also the primary reason for cancer-related death in women, especially in white women worldwide (Desantis et al., 2016). Moreover, the increase in breast cancer incidence between 2005 and 2014 was reported to be by 1.7% per year among Asian women (Desantis et al., 2017). Current clinical cancer treatments including surgical therapy, radiotherapy, chemotherapy and biotherapy are used to treat breast cancer. Progress has been made in reducing or removing primary tumor sites in the past several decades. However, relapse and metastasis, which are the main causes of breast cancer-related death, are severely intractable in the clinic and remain poorly understood (Lu et al., 2009).