Hydroxytyrosol inhibits cancer stem cells and the metastatic capacity of triple-negative breast cancer cell lines by the simultaneous targeting of epithelial-to-mesenchymal transition, Wnt/β-catenin and TGFβ signaling pathways
- 363 Downloads
This study was aimed to determine the impact of hydroxytyrosol (HT), a minor compound found in olive oil, on breast cancer stem cells (BCSCs) and the migration capacity of triple-negative breast cancer (TNBC) cell lines through the alteration of epithelial-to-mesenchymal transition (EMT) and embryonic signaling pathways.
BCSCs self-renewal was determined by the mammosphere-forming efficiency in SUM159PT, BT549, MDA-MB-231 and Hs578T TNBC cell lines. Flow cytometric analysis of CD44+/CD24−/low and aldehyde dehydrogenase positive (ALDH+) subpopulations, migration by the “wound healing assay”, invasion and Western blot of EMT markers and TGFβ signaling were investigated in SUM159PT, BT549 and MDA-MB-231 cell lines. Wnt/β-catenin signaling was assessed by Western blot in BT549 cells expressing WNT1 and MDA-MB-231 cells. Changes in TGFβ activity was determined by SMAD Binding Element (SBE) reporter assay.
HT reduced BCSCs self-renewal, ALDH+ (aldehyde dehydrogenase) and CD44+/CD24−/low subpopulations, tumor cell migration and invasion. Consistently, HT suppressed Wnt/β-catenin signaling by decreasing p-LRP6, LRP6, β-catenin and cyclin D1 protein expression and the EMT markers SLUG, ZEB1, SNAIL and VIMENTIN. Finally, HT inhibited p-SMAD2/3 and SMAD2/3 in SUM159PT, BT549 and MDA-MB-231 cells, what was correlated with a less TGFβ activity.
In conclusion, we report for the first time the inhibitory role of HT on BCSCs and tumor cell migration by targeting EMT, Wnt/β-catenin and TGFβ signaling pathways. Our findings highlight the importance of the chemopreventive compound HT as a novel candidate to be investigated as an alternative targeted therapy for TNBC.
KeywordsHydroxytyrosol Olive oil Triple-negative breast cancer Cancer stem cells Epithelial-to-mesenchymal transition
Funding was provided by Instituto de Salud Carlos III (CP14/00197, PI15/00336, PIE16/00045), European Regional Development Fund (European Union), and the Chair “Doctors Galera-Requena in Cancer Stem Cell Research”.
Compliance with ethical standards
Conflict of interest
The authors declare no potential conflict of interests.
- 4.Idowu MO, Kmieciak M, Dumur C et al (2012) CD44(+)/CD24(-/low) cancer stem/progenitor cells are more abundant in triple-negative invasive breast carcinoma phenotype and are associated with poor outcome. Hum Pathol 43:364–373. https://doi.org/10.1016/j.humpath.2011.05.005 CrossRefPubMedGoogle Scholar
- 38.Avtanski DB, Nagalingam A, Bonner MY et al (2014) Honokiol inhibits epithelial-mesenchymal transition in breast cancer cells by targeting signal transducer and activator of transcription 3/Zeb1/E-cadherin axis. Mol Oncol 8:565–580. https://doi.org/10.1016/j.molonc.2014.01.004 CrossRefPubMedPubMedCentralGoogle Scholar
- 43.Sun M, Zhang N, Wang X et al (2016) Hedgehog pathway is involved in nitidine chloride induced inhibition of epithelial–mesenchymal transition and cancer stem cells-like properties in breast cancer cells. Cell Biosci 6:44. https://doi.org/10.1186/s13578-016-0104-8 CrossRefPubMedPubMedCentralGoogle Scholar
- 47.González-Santiago M, Fonollá J, Lopez-Huertas E (2010) Human absorption of a supplement containing purified hydroxytyrosol, a natural antioxidant from olive oil, and evidence for its transient association with low-density lipoproteins. Pharmacol Res 61:364–370. https://doi.org/10.1016/j.phrs.2009.12.016 CrossRefPubMedGoogle Scholar
- 52.Li Y, Jiang F, Chen L et al (2015) Blockage of TGFβ-SMAD2 by demethylation-activated miR-148a is involved in caffeic acid-induced inhibition of cancer stem cell-like properties in vitro and in vivo. FEBS Open Bio 5:466–475. https://doi.org/10.1016/j.fob.2015.05.009 CrossRefPubMedPubMedCentralGoogle Scholar
- 56.Bhuvanalakshmi G, Rangappa KS et al (2017) Breast cancer stem-like cells are inhibited by diosgenin, a steroidal saponin, by the attenuation of the Wnt β-Catenin signaling via the Wnt antagonist secreted frizzled related protein-4. Front Pharmacol 8:124. https://doi.org/10.3389/fphar.2017.00124 CrossRefPubMedPubMedCentralGoogle Scholar
- 59.Zhou B, Liu Y, Kahn M et al (2012) Interactions between β-catenin and transforming growth factor-β signaling pathways mediate epithelial-mesenchymal transition and are dependent on the transcriptional co-activator cAMP-response element-binding protein (CREB)-binding protein (CBP). J Biol Chem 287:7026–7038. https://doi.org/10.1074/jbc.M111.276311 CrossRefPubMedPubMedCentralGoogle Scholar