Functional Assays for Detection of Cancer Stem Cells

Abstract

Cancer stem cells (CSCs) are considered to be a population of tumor cells, which are responsible for tumor initiation and progression. They are also involved in metastasizing and may be a possible cause of multidrug resistance and tumor recurrence. CSCs possess the ability to self renew and show a tumorigenic potential. Functional assays, which enable the detection of these properties, represent the main tool for identification of CSCs. This article summarizes both in vitro and in vivo methods used to identify the CSCs with emphasis on recently employed techniques of CSCs detection. In vivo tumorigenicity assay, sphere formation assay and colony forming unit assay belong to the most commonly used functional assays. Further, label retention assay and aldehyde dehydrogenase activity assay are described in this article. Key words: cancer stem cells - functional assays - tumorigenicity - tumor spheres - colony forming unit assay - side population cells - aldehyde dehydrogenase The study was supported by grant of Internal Grant Agency of the Czech Ministry of Health No. NT13443-4 and by the European Regional Development Fund and the State Budget of the Czech Republic - RECAMO, CZ.1.05//2.1.00/03.0101 and by the project CEB, OP VK CZ.1.07/2.3.00/20.0183. The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE "uniform requirements" for biomedical papers.Submitted: 16. 1. 2014Accepted: 4. 4. 2014.