EpCAM is critical for tumor proliferation and oxaliplatin chemoresistance in EpCAMhigh/CD44+ colorectal cancer stem cells

Objectives A small subpopulation of colorectal cancer stem cells (CSCs) possess the ability to self-renew and the capacity to initiate the original tumor. EpCAM(high)/CD44(+) cells are regarded as CSCs in colorectal cancer. The present study was undertaken to investigate the significance of EpCAM in the in vitro proliferation ability and oxaliplatin chemoresistance of EpCAM(high)/CD44(+) colorectal CSCs. Methods We applied fluorescence-activated cell sorting (FACS) to separate the EpCAM(high)/CD44(+) subset from human colorectal cancer cell line HCT116. We also used siRNA targeting EpCAM to create EpCAM(-)/CD44(+) subpopulation. Then we compared EpCAM(high)/CD44(+) cells and EpCAM(-)/CD44(+) cells for proliferation ability and the chemoresistance to oxaliplatin by CCK8 assay. Results The EpCAM(high)/CD44(+) subset comprises almost 6.25 +/- 0.09% in cell line HCT116, and the EpCAM(-)/CD44(+) cells displayed a significantly lower proliferation ability and weaker oxaliplatin chemoresistance than the EpCAM(high)/CD44(+) cells. Conclusions EpCAM is critical for tumor proliferation and oxaliplatin chemoresistance in EpCAM(high)/CD44(+) colorectal CSCs.