Cancer is a complex and heterogeneous disease, and cancer cells dynamically interact with the mechanical microenvironment such as hydrostatic pressure, fluid shear, and interstitial flow. These factors play an essential role in cell fate and circulating tumor cell heterogeneity, and can influence the cellular phenotype. In this study, a peristaltic continuous flow reactor is designed and applied to HCT-116 colorectal carcinoma cells to mimic the fluid dynamics of circulation. With this intervention, a CD44/CD24-cell subpopulation emerges, and 100 genes are significantly regulated. The expression of cells at 4 h in the flow reactor is very similar to TGF-s treatment, which is an inducer of epithelial-mesenchymal transition. ATF3 and SERPINE1 are significantly upregulated in these groups, suggesting that the mesenchymal transition is induced through this signaling pathway. This flow reactor model is satisfactory on its own to reprogram colorectal cancer cells toward a more mesenchymal niche mimicking circulation of the blood.

A Circulating Bioreactor Reprograms Cancer Cells Toward a More Mesenchymal Niche

Objective: To generate tumor spheres from colorectal cancer cell line HCT116 in serum-free medium (SFM) and to observe the location of the cancer stem cell surface marker CD133 as well as the ratio of CD133+ cells so as to investigate the possible relationship between the epithelial-mesenchymal transition and metastatic ability of tumor spheres. Methods: Human HCT116 colorectal cancer cells were cultured in SFM supplemented with cell growth factors. The location of cancer stem cell marker CD133 in tumor spheres was observed by confocal laser scanning microscopy, and the content of CD133+ cells in tumor spheres was detected by flow cytometry (FCM). Transwell chamber assay, immunofluorescence and reverse transcription polymerase chain reaction (RT-PCR) were applied to examine the metastatic ability of tumor spheres in vitro and the expressions of epithelial-mesenchymal-related key markers. Results: The surface marker CD133 was located on cell membrane, and the content of CD133+ cells was significantly increased in HCT116 tumor spheres. The expressions of mesenchymal markers N-cadherin and Vimentin were highly elevated, while the expression of epithelial marker E-cadherin was reduced. The metastatic ability of cell sphere was higher than that of monolayer cells. Conclusion: HCT116 tumor spheres are enriched with CD133+ cells. The surface marker CD133 is located on the cell membrane. The cell spheres may get higher metastatic ability through epithelial-mesenchymal transition. DOI:10.3781/j.issn.1000-7431.2011.11.004

Nai-jin Wu

Papers

Metastasis-related characteristics of tumor spheres derived from human colorectal cancer cell line HCT116