Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2013 Jul 26;14(8):15655-68.
doi: 10.3390/ijms140815655.

Resveratrol sensitizes tamoxifen in antiestrogen-resistant breast cancer cells with epithelial-mesenchymal transition features

Xiao-Peng Shi  1 , Shan Miao, Yin Wu, Wei Zhang, Xiao-Fang Zhang, Hua-Zhao Ma, Hai-Li Xin, Juan Feng, Ai-Dong Wen, Yan Li
Affiliations

Resveratrol sensitizes tamoxifen in antiestrogen-resistant breast cancer cells with epithelial-mesenchymal transition features

Xiao-Peng Shi et al. Int J Mol Sci. .

Abstract

Tamoxifen resistance remains to be a huge obstacle in the treatment of hormone-dependent breast cancer, and this therefore highlights the dire need to explore the underlying mechanisms. The epithelial-mesenchymal transition (EMT) is a molecular process through which an epithelial cell transfers into a mesenchymal phenotype. Roles of EMT in embryo development, cancer invasion and metastasis have been extensively reported. Herein, we established tamoxifen-resistant MCF-7/TR breast cancer cells and showed that MCF-7/TR cells underwent EMT driven by enhanced endogenous TGF-β/Smad signaling. Ectopic supplement of TGF-β promoted in MCF-7 cells a mesenchymal and resistant phenotype. In parallel, we demonstrated that resveratrol was capable of synergizing with tamoxifen and triggering apoptosis in MCF-7/TR cells. Further Western blot analysis indicated that the chemosensitizing effects of resveratrol were conferred with its modulation on endogenous TGF-β production and Smad phosphorylation. In particular, 50 μM resveratrol had minor effects on MCF-7/TR cell proliferation, but could significantly attenuate endogenous TGF-β production and the Smad pathway, ultimately leading to reversion of EMT. Collectively, our study highlighted distinct roles of EMT in tamoxifen resistance and resveratrol as a potential agent to overcome acquired tamoxifen resistance. The molecular mechanism of resveratrol chemosensitizing effects is, at least in part, TGF-β/Smad-dependent.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Evidence of epithelial-mesenchymal transition (EMT) in breast cancer tamoxifen-resistant MCF-7/TR cells. (A) In comparison with the parental MCF-7 cells, methyl thiazolyl tetrazolium (MTT) assay showed that the daughter MCF-7/TR cells were resistant to tamoxifen treatment; (B) when observed under microscope at 200× magnification, parental MCF-7 cells displayed an epithelioid and cobblestone appearance. In contrast, the phenotypic changes observed in resistant MCF-7/TR cells included loss of cell polarity, causing a spindle-shaped morphology and increased formation of pseudopodia. Scale bar = 10 μm; (C) immunofluorescent cytochemistry and confocal analysis showed that E-cadherin was markedly expressed in MCF-7 cells, while MCF-7/TR cells expressed vimentin.
Figure 2
Figure 2
Western blot analysis of EMT biomarkers and transcription factors. (A) Western blot demonstrated that MCF-7 cells predominantly expressed epithelial phenotype markers, but MCF-7/TR cells predominantly expressed mesenchymal markers; (B) western blot analysis of EMT transcription factors, Smad, Snail, Slung and Twist, in MCF-7 and MCF-7/TR cells.
Figure 3
Figure 3
Measurement of TGF-β and Smad signaling in MCF-7 and MCF-7/TR cells. (A) The production of endogenous TGF-β in the supernatant of MCF-7 and MCF-7/TR cells without or with resveratrol treatment were measured by ELISA. Data are expressed as the mean ± SEM from three independent experiments performed in triplicate. p < 0.01 vs. MCF-7 cell and p < 0.05 vs. resveratrol treatment; (B) Baseline expressions of p-Smad2, Smad2, p-Smad3 and Smad3 in MCF-7 and MCF-7/TR cells. Upon resveratrol treatment, the Smad cascade was inhibited in MCF-7/TR cells. β-actin was employed as equal loading.
Figure 4
Figure 4
Effects of TGF-β on tamoxifen sensitivity. (A) The cancer cells undergoing apoptosis were quantitatively determined by flow cytometry; (B) Akt and ERK1/2 phosphorylation status in tamoxifen-treated MCF-7 cells, with or without TGF-β pretreatment.
Figure 5
Figure 5
Effects of 48 h resveratrol treatment on MCF-7 and MCF-7/TR cell viability measured by MTT assay. Data are expressed as the mean ± SEM from three independent experiments performed in triplicate.
Figure 6
Figure 6
Resveratrol reverses EMT and triggers MCF-7/TR cell apoptosis. Western blot showed (A) 50 μM tamoxifen co-treatment with resveratrol dose-dependently reduced Akt and ERK1/2 phosphorylation, promoted caspase-3 activation and polyADP-ribosepolymerase (PARP) cleavage; (B) Resveratrol also restored epithelial marker expressions and reversed EMT in MCF-7/TR cells. β-actin was employed as equal loading.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Jemal A., Siegel R., Ward E., Hao Y., Xu J., Thun M.J. Cancer statistics, 2009. CA Cancer J. Clin. 2009;59:225–249. - PubMed
    1. Miller W.R., Bartlett J.M., Canney P., Verrill M. Hormonal therapy for postmenopausal breast cancer: The science of sequencing. Breast Cancer Res. Treat. 2007;103:149–160. - PubMed
    1. Perey L., Paridaens R., Hawle H., Zaman K., Nolé F., Wildiers H., Fiche M., Dietrich D., Clément P., Köberle D., et al. Clinical benefit of fulvestrant in postmenopausal women with advanced breast cancer and primary or acquired resistance to aromatase inhibitors: Final results of phase II Swiss Group for Clinical Cancer Research Trial (SAKK 21/00) Ann. Oncol. 2007;18:64–69. - PubMed
    1. Gutierrez M.C., Detre S., Johnston S., Mohsin S.K., Shou J., Allred D.C., Schiff R., Osborne C.K., Dowsett M. Molecular changes in tamoxifen-resistant breast cancer: Relationship between estrogen receptor, HER-2, and p38 mitogen-activated protein kinase. J. Clin. Oncol. 2005;23:2469–2476. - PubMed
    1. Holm C., Rayala S., Jirström K., Stål O., Kumar R., Landberg G. Association between Pak1 expression and subcellular localization and tamoxifen resistance in breast cancer patients. J. Natl. Cancer Inst. 2006;98:671–680. - PubMed

Publication types

MeSH terms

LinkOut - more resources