CD133-positive tumor cell content is a predictor of early recurrence in colorectal cancer

Background

The aims of this study were to demonstrate the tumorigenicity of CD133+ colon cancer cells in vitro, analyze the correlations between spheroid formation and clinicopathologic variables, and screen for overexpressed genes in CD133+ colon cancer stem cells. Moreover, the aim of this study was to establish a living tumor tissue bank using surgically resected specimens.

Methods

Using LoVo cell line, we isolated CD133+ cells and performed clonogenic assay and animal experiment to test tumorigenicity of CD133+ cells. Twenty-nine surgical samples were freshly collected from 27 patients who received curative or palliative surgery, and the samples were mechanically and enzymatically dissociated into single cells.

Results

We confirmed the enhanced tumorigenicity of CD133+ cells isolated from LoVo cell line both in vitro and in vivo. Of these 29 samples, 8 (28%) contained >3% CD133+ cells. Sphere formation was significantly higher in samples from patients with lymphatic invasion than in those without lymphatic invasion [54.5% (6/11) vs. 12.5% (2/16); P=0.033] and in samples containing >3% of CD133+ cells than in those containing ≤3% of CD133+ cells [36.4% (4/11) vs. 0% (0/16); P=0.019].

Conclusions

These findings indicate that CD133 is a valid marker for identifying cancer stem cells from fresh surgically resected colorectal cancer tissues. Furthermore, we successfully established a living tumor tissue bank using surgically resected colorectal tissues with a viability of >70%.