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Suppressive role of Viola odorata extract on malignant characters of mammosphere-derived breast cancer stem cells

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Mammospheres are breast cancer stem cells (BCSCs) that could be yielded through culturing cells in non-adherent and non-differentiating condition. With regard to therapy resistance of cancer stem cells (CSCs), it is essential to discover efficient approaches targeting CSCs. Viola odorata extract has been considered as a traditional herbal anti-metastatic drug in several cancer cells. Effect of this drug on BCSCs has not been clearly identified. Current study tries to detect and to compare effect of Viola odorata extract on malignant characterization of breast cancer cell lines and BCSCs.

Materials and methods

MCF7 and SKBR3 and their derived mammospheres as BCSCs were used and the effect of alcoholic extraction of Viola odorata on apoptosis and malignant characters of MCF7, SKBR3 and their derived BCSCs were analyzed and compared.


Viola odorata extract induced cell death in MCF7, SKBR3 and their derived mammospheres through apoptosis without any effects on MCF10A. Also, this extract showed anti-migratory, anti-invasion and anti-colony formation activity in MCF7, SKBR3 and their derived mammospheres which was significantly more in MCF7- and SKBR3-derived mammospheres. Also, this extract decreased size and volume of tumors generated by MCF7, SKBR3 and their derived mammospheres in chicken embryo model.


Viola odorata extract exerted anti-cancerous activity on both breast cancer cell lines and their derived BCSCs. Anti-cancerous activity of this extract was significantly more in MCF7-, SKBR3-derived mammospheres in comparison with dedicated cell lines. Data suggest that Viola odorata extract mostly targets cancerous cells, not normal cells with exception in high concentration. It acts in a cell-dependent manner.

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Aldehyde dehydrogenase


Basic fibroblast growth factor


Breast cancer stem cells


Cancer stem cells


Chorioallantoic membrane




Dulbecco’s modified Eagle’s medium/F12


Epidermal growth factor


Epigallocatechin gallate


Epithelial-specific antigen


Estrogen receptor


Extracellular matrix


Fetal bovine serum

H&E staining:

Hematoxylin and eosin staining


High-performance liquid chromatography


Human epidermal growth factor receptor 2




50% Inhibitory concentration


Oral squamous cell carcinoma




Poly ADP ribose polymerase


Progesterone receptor




Tumor-initiating cells


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We thank our great colleague Mr. Abbas Kiani Esfahani for his technical assistance on flow cytometry. Also, we thank Goldaru Company, for the gift-giving alcoholic Viola odorata extract.


This project was supported by the Goldaru company to approve the anti-cancerous effects of Viola odorata extract. This project was funded by a grant-in-aid of research from Iran National Science Foundation (Award no. 93021399) to K. G., as the Principal Investigator.

Author information

SY: designing research studies, conducting experiments, acquiring data, analyzing data, providing reagents, and writing the manuscript. DN: designing research studies, conducting experiments, data interpretation. FSF: designing research studies, data interpretation, manuscript writing, and final approval of the manuscript. MT: data interpretation, conducting experiments. FM: data interpretation, conducting experiments. TG: data interpretation, conducting experiments. MHNE: designing research studies, data interpretation, manuscript writing, and final approval of the manuscript. KG: designing research studies, data interpretation, manuscript writing, and final approval of the manuscript.

Correspondence to F. Seyed Forootan or K. Ghaedi.

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The permission to use chicken embryo based on the standard protocols was obtained by Ethics Committee of Royan Institute (The permission to use chick embryo based on the standard protocols was obtained by Ethics Committee of Royan Institute (Project no. IR ACECR ROYAN REC IR ACECR ROYAN REC).

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Yousefnia, S., Naseri, D., Seyed Forootan, F. et al. Suppressive role of Viola odorata extract on malignant characters of mammosphere-derived breast cancer stem cells . Clin Transl Oncol (2020). https://doi.org/10.1007/s12094-020-02307-9

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  • Breast cancer stem cell (BCSC)
  • Mammosphere
  • Viola odorata
  • Invasion
  • Tumorigenicity