Head and neck cancer stem cells: the side population

Area of Science:

• Oncology
• Cancer Biology
• Stem Cell Research

Background:

• The cancer stem cell (CSC) theory posits that a subpopulation of cancer cells is responsible for tumor growth and self-renewal.
• Side population (SP) cells, identified by their ability to efflux Hoechst 33342 dye, share characteristics with CSCs.
• This suggests that SP cells isolated from tumors may represent CSCs.

Purpose of the Study:

• To investigate whether side population (SP) cells isolated from head and neck cancer exhibit cancer stem cell (CSC)-like properties.
• To establish a method for isolating and studying CSCs in head and neck cancer.

Main Methods:

• Experimental isolation and analysis of SP cells from a head and neck cancer cell line.
• Assessment of CSC-like characteristics, including self-renewal, drug resistance, gene expression, and tumor formation in an animal model.
• Identification of SPs in primary human tumors.

Main Results:

• Isolated SP cells demonstrated self-renewal capacity, generating both SP and non-side population (NSP) cells from single cells.
• SP cells exhibited lower active β-catenin expression and increased resistance to 5-fluorouracil.
• SP cells showed higher expression of Bmi-1 and ABCG2, and were capable of forming tumors in vivo, unlike NSP cells.
• SPs were detected in two primary human head and neck tumors.

Conclusions:

• The findings support the hypothesis that SP cells in head and neck cancer possess CSC properties.
• This study provides a viable method for the isolation and subsequent study of CSCs in this cancer type.