Propolis reduces the stemness of head and neck squamous cell carcinoma

Felipe Nör; Carolina Nör; Letícia W Bento; Zhaocheng Zhang; Walter A Bretz; Jacques E Nör

doi:10.1016/j.archoralbio.2021.105087

Propolis reduces the stemness of head and neck squamous cell carcinoma

Arch Oral Biol. 2021 May:125:105087. doi: 10.1016/j.archoralbio.2021.105087. Epub 2021 Feb 19.

Authors

Felipe Nör¹, Carolina Nör², Letícia W Bento³, Zhaocheng Zhang³, Walter A Bretz⁴, Jacques E Nör⁵

Affiliations

¹ Department of Cariology, Restorative Sciences, Endodontics, University of Michigan School of Dentistry, Ann Arbor, MI, USA; Department of Oral Pathology, Radiology & Medicine, University of Iowa College of Dentistry, Iowa City, IA, USA. Electronic address: felipe-nor@uiowa.edu.
² Department of Cariology, Restorative Sciences, Endodontics, University of Michigan School of Dentistry, Ann Arbor, MI, USA; Programme in Developmental and Stem Cell Biology, Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON, Canada.
³ Department of Cariology, Restorative Sciences, Endodontics, University of Michigan School of Dentistry, Ann Arbor, MI, USA.
⁴ Microsolum, Huntington Beach, CA, USA.
⁵ Department of Cariology, Restorative Sciences, Endodontics, University of Michigan School of Dentistry, Ann Arbor, MI, USA; Department of Biomedical Engineering, University of Michigan College of Engineering, Ann Arbor, MI, USA; Department of Otolaryngology, University of Michigan School of Medicine, Ann Arbor, MI, USA.

Abstract

Objective: To evaluate the effect of Brazilian propolis on head and neck cancer stem cells in vitro.

Methods: Head and neck squamous cell carcinoma (HNSCC) cell lines (UM-SCC-17B and UM-SCC-74A), human keratinocytes (HK), and primary human dermal microvascular endothelial cells (HDMEC) were treated with 0.5, 5.0, or 50 μg/mL green, brown or red Brazilian propolis or vehicle control for 24, 36, and 72 h. Cell viability was evaluated by Sulforhodamine B assay. Western blots evaluated expression of cancer stem cell (CSC) markers (i.e. ALDH, CD44, Oct-4, Bmi-1) and flow cytometry was performed to determine the impact of propolis in the fraction of CSC, defined as ALDH^highCD44^high cells.

Results: propolis significantly reduced cell viability of HNSCC and HDMEC cells, but not HK. Notably, red propolis caused a significant reduction in the percentage of CSC, reduced the number of orospheres, and downregulated the expression of stem cell markers.

Conclusions: Collectively, our data demonstrate an anti-CSC effect of propolis, and suggest that propolis (i.e. red propolis) might be beneficial for patients with head and neck cancer.

Keywords: Cancer stem cell; Head and neck squamous cell carcinoma; Orospheres; Propolis; Stemness.

MeSH terms

Brazil
Carcinoma, Squamous Cell* / drug therapy
Cell Line, Tumor
Endothelial Cells
Head and Neck Neoplasms* / drug therapy
Humans
Propolis* / pharmacology
Squamous Cell Carcinoma of Head and Neck / drug therapy

Substances

Propolis

Grants and funding

R01 DE021139/DE/NIDCR NIH HHS/United States