Proteomic analysis of CD44(+) and CD44(−) gastric cancer cells
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CD44 is a cell surface protein and it is widely used as a cancer stem cell marker in various cancer types including gastric cancer. We conducted proteomic analysis in CD44(+) and CD44(−) gastric cancer cells to understand characteristics of CD44(+) and CD44(−) cells. In the present study, we sorted cells from the gastric cancer cell line MKN45 according to CD44 expression to separate out CD44(+) and CD44(−) cells. And we conducted RT-PCR to identify mRNA expression of cancer stem cell markers in CD44(+) and CD44(−) cells. Cancer stem cell markers showed upregulated expression in CD44(+) cells. Next, we performed two-dimensional electrophoresis analysis to determine the differential expression pattern of proteins in each group; control, CD44(+), and CD44(−) MKN45 cells. We found a total of 113 spots that varied in expression between CD44(+) and CD44(−) cells, and subjected 20 of those protein spots to MALDI-MS. We selected the three proteins (HSPA8; heat shock cognate 71 kDa protein isoform 1, ezrin, α-enolase) upregulated in CD44(+) cells than CD44(−) cells and one protein (prohibitin) showed increased expression in CD44(−) cells. We validated the protein expression levels of four selected proteins by Western blot. We suggest that our study could be a helpful background to study CD44(+) cancer stem-like cells and differences between CD44(+) and CD44(−) cells in gastric cancer.
KeywordsCancer stem cells CD44 Gastric cancer 2-DE
This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (grant number NRF-2013R1A1A2009707) and also supported by a faculty research grant of Yonsei University College of Medicine (6-2008-0229,6-2009-0148).
Conflict of interest
The authors have no conflicts of interest to declare.
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