A Novel 5-Fluorouracil-resistant Human Esophageal Squamous Cell Carcinoma Cell Line Eca-109/5-Fu with Significant Drug Resistance-Related Characteristics

5-Fluorouracil (5-FU) is used for the clinical treatment of esophageal squamous cell carcinomas (ESCCs), yet it also induces chemoresistant cancer cells during treatment, which leads to the failure of the therapy. To further explore the resistance mechanism of 5-FU in ESCC, we established the 5-FU-resistant ESCC cell line Eca-109/5-FU, which was prepared by the stepwise exposure to increasing 5-FU concentrations. MTT assay and nude mouse xenograft models were used to test the drug resistance and proliferation of Eca-109 and Eca-109/5-FU cells in vitro and in vivo. Apoptosis and cell cycle distribution were determined using flow cytometry. Drug resistance-related proteins were detected by western blotting. Metabolomic profiles were obtained from nuclear magnetic resonance (NMR) tests. In regards to Eca-109/5-FU, the decreased susceptibility to 5-FU was determined in vitro and in vivo with slower rate of proliferation. Drug resistance related proteins (multidrug resistance-associated protein 1 and ATP-binding cassette superfamily G member 2), epithelial-to-mesenchymal transition (EMT)-related proteins (E-cadherin and vimentin) and cancer stem cell-related proteins (prominin-1 and hyaluronate receptor) exhibited significant differences between the two cell lines. The 5-FU-resistant cell line Eca-109/5-FU achieved the ability to tolerate 5-FU, which may depend on significant drug resistance-related characteristics, such as EMT and cancer stem cell-like properties. The metabolism of Eca-109/5-FU was altered, and more than 15 metabolites was found to contribute to the difference in the metabolite profile, such as lactate, glutamate, taurine, glutamine, proline, aspartate, methanol, cystine, glycine and uracil. Our results identified that the resistant cell line Eca-109/5-FU showed quite different characteristics compared with the parental Eca-109 cells. The Eca-109/5-FU cell line provides an experimental model for further steps to select chemotherapeutic sensitizers.