A New Method for Identifying Stem-Like Cells in Esophageal Cancer Cell Lines
Journal Article
TN, Almanaa . 2013
Publication Online URL:
Magazine \ Newspaper:
J Cancer
Issue Number:
(7)
Volume Number:
4
Pages:
536-548
Publication Abstract:
Cancer stem cells (CSCs) appear to resist chemo-radiotherapy and initiate tumor recurrence in
patients. Isolation and further characterization of this subpopulation is important for targeting
CSCs. Flow cytometry using Aldefluor, a fluorescent substrate of aldehyde dehydrogenase, has
been used to isolate CSCs from various cancer cell lines. However, new techniques are needed to
locate and identify CSCs in culture for live-cell analyses such as fluorescence microscopy without
introducing artifacts during cell sorting and to observe CSC and non-CSC interactions. Previously,
we characterized a distinct CSC subpopulation within human esophageal cancer cell lines (ESCC).
In this study we introduce the attached-cell Aldefluor method (ACAM) to detect CSCs in ESCC
cell lines (KY-5, KY-10, TE-1, TE-8, YES-1, YES-2). To validate this technique, we isolated CSCs
from the YES-2 parental line using standard Aldefluor flow cytometry to create a cell line enriched
in CSCs (YES-2CSC). This line showed significantly greater ACAM staining and higher CD44 levels
than YES-2. ACAM also showed significantly higher ALDH activity in YES-2CSC than in YES-2S, a
cell line that has a diminished CSC subpopulation after having survived treatment with curcumin.
ACAM stained cells within tumorspheres made from the CSC-enriched line but not differentiating
cells from the tumorspheres. This study also demonstrates a new method for generating and
growing tumorspheres without the growth factor supplements normally used in medium to form
tumorspheres. ACAM should be evaluated using other cancer cell lines to further substantiate its
effectiveness and to characterize CSCs in culture through various imaging techniques.