Oregano demonstrates distinct tumour-suppressive effects in the breast carcinoma model
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There has been a considerable interest in the identification of natural plant foods for developing effective agents against cancer. Thus, the anti-tumour effects of oregano in the in vivo and in vitro breast cancer model were evaluated.
Lyophilized oregano (ORE) was administered at two concentrations of 0.3 and 3 % through diet. The experiment was terminated 14 weeks after carcinogen administration. At autopsy, mammary tumours were removed and prepared for histopathological and immunohistochemical analysis. Moreover, in vitro evaluation in MCF-7 cells was carried out.
Low-dose ORE suppressed tumour frequency by 55.5 %, tumour incidence by 44 %, and tumour volume by 44.5 % compared to control animals. Analysis of rat tumour cells showed Ki67, VEGFR-2, CD24, and EpCAM expression decrease and caspase-3 expression increase after low-dose ORE treatment. High-dose ORE lengthened tumour latency by 12.5 days; moreover, Bcl-2, VEGFR-2, CD24, and EpCAM expression decrease and caspase-3 expression increase in carcinoma cells were observed. Histopathological analysis revealed a decrease in the ratio of high-/low-grade carcinomas in both treated groups. In vitro studies showed that ORE decreased survival and proliferation of MCF-7 cells. In ORE-treated MCF-7 cells, an increase in cells expressing sub-G 0/G 1 DNA content and an increase in the percentage of annexin V/PI positive MCF-7 cells were observed. In vitro, both caspase-dependent and possible non-caspase-dependent apoptotic pathways were found. The deactivation of anti-apoptotic activity of Bcl-2, a decrease in mitochondrial membrane potential, and the activation of mitochondrial apoptosis pathway were observed in the ORE-treated MCF-7 cells.
Our results demonstrate, for the first time, a distinct tumour-suppressive effect of oregano in the breast cancer model.
KeywordsMammary carcinogenesis Rat Oregano Cancer stem cells Angiogenesis Apoptosis Cell proliferation MCF-7 cells
Cancer stem cells
Flow cytometry analysis
Epithelial cellular adhesion molecule
Limit of quantification
Human adenocarcinoma cell line, oestrogen receptor positive
- ORE 0.3/ORE 3
Experimental group with dietary administered oregano in a concentration of 0.3 and 3 %
Vascular endothelial growth factor
Vascular endothelial growth factor receptor-2
Very low-density lipoprotein
This work was supported by the Scientific Grant Agency of the Ministry of Education of the Slovak Republic under the Contract No. VEGA 1/0108/16 and 1/0290/16 and by the Slovak Research and Development Agency under the Contract Nos. APVV-0325-07 and APVV-0550-11. This work was supported by the Grant “Martin Biomedical Centre” (ITMS: 26220220187), “Competence center for research and development in diagnosis and therapy”, code: 26220220153, and the Grant FNUSA-ICRC (No. CZ.1.05/1.1.00/02.0123), both projects co-funded from EU sources and European Regional Development Fund. This study was also supported by the project Medicínsky univerzitný park v Košiciach (MediPark, Košice) ITMS:26220220185 supported by Operational Programme Research and Development (OP VaV-2012/2.2/08-RO) (Contract No. OPVaV/12/2013). We thank to Eva Jakubovičová, Agáta Rešetárová, and Margaréta Kondeková for technical support.
Compliance with ethical standards
Conflict of interest
The authors state that there are no conflicts of interest.
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