Cancer stem cells are widely studied as a potential therapeutic target in cancer research. Their expression of cell surface biomarkers such as EpCAM, CD44, and CD133 have been well characterized as a method for identification and enrichment from heterogeneous populations. Additional biomarkers with more functional relevance to self-renewal such as the transcription factors Sox-2 and Nanog, are intracellular and traditionally require fixation and permeabilization of the sample. Here we describe a method for identification and enrichment of live cancer stem cells based on intracellular biomarker expression.

Live human head and neck squamous cell carcinoma (HNSCC) cell lines, UM-SCC-47 and UM-SCC-104 were used as a model for Cancer stem cells in a mixed population. They were assayed for their expression of EpCAM, CD44, and CD133 by flow cytometry. Additionally, Aldehyde dehydrogenase (ALDH) activity was also detected in a population of the HNSCC cell lines further corroborating the presence of a cancer stem cell population. Live cell probes specific to Nanog and Sox-2 were used to enrich for cells expressing the targets of interest through Fluorescent Activated Cell Sorting (FACS).

This live cell biomarker approach was also recently demonstrated on solid tumors which were digested and cultured as single cells where they were then incubated with the live cell probes. FACS sorting was utilized to enrich for a cancer stem cell population. More importantly after detection these cells remain live and intact allowing them to be returned to culture and further studied.

Citation Format: Don Weldon, Yuko Williams, Amish Patel, Steven McClellan. Live cell detection of intracellular biomarkers maintains cancer stem cells for further experimentation. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2530.