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IntroductionChemoresistance is a major barrier in the treatment of colorectal cancer (CRC) and many other cancers. ENO1 has been associated with various biological characteristics of CRC. This study aimed to investigate the function of ENO1 in regulating 5-Fluorouracil (5-FU) resistance in CRC.MethodsENO1 level in 120 pairs of tumor tissues and adjacent normal tissues was examined by immunohistochemistry, and the correlation between ENO1 expression and prognosis was explored by survival analysis. Its role and potential mechanisms in regulating 5-FU resistance in CRC were studied by Western blotting, MTT assay, colony formation assay and transwell invasion assay. Murine xenograft assay was implied to verify the results in vivo.ResultsOur study indicated that ENO1 was elevated in CRC tissues and was associated with poor patient prognosis. High levels of ENO1 expression were detected as a significant influencing factor for overall survival. Furthermore, ENO1 expression was found to have increased in drug-resistant cells (HCT116/5-FU and SW620/5-FU) constructed by increasing concentrations of 5-FU. Knockdown of ENO1 markedly increased the drug susceptibility and inhibited the proliferation and migration ability of HCT116/5-FU and SW620/5-FU cells. It was found that down-regulation of ENO1 inhibited the epithelial-mesenchymal transformation (EMT) signaling process. Finally, a murine xenograft assay verified that the depletion of ENO1 alleviated 5-FU resistance.ConclusionThis study identified that ENO1 regulated 5-FU resistance via the EMT pathway and may be a novel target in the prevention and treatment of 5-FUresistant CRC.

Poly(2,6-dimethyl-phenylene oxide)s (PPO)s with thermally crosslinkable azide groups and “side-chain-type” architecture containing quaternary ammonium and triazole groups were synthesized by Cu-catalyzed “click chemistry”. Tough and flexible anion exchange membranes (AEMs) were prepared by solution casting at 70 °C. By simple thermal crosslinking at 135 °C for 18 h, controllably crosslinked PPO AEMs were obtained. Key properties of the crosslinked AEMs, such as ion exchange capacity, thermal stability, water uptake, hydroxide conductivity and alkaline stability were investigated. The crosslinked membranes maintained high hydroxide conductivities despite their extremely low water uptake (up to 57.5 mS cm–1 at room temperature, water uptake of 34.5 wt%). The unusually low water uptake and good hydroxide conductivity may be attributed to the crosslinked, “side-chain-type” structures of pendent triazole and cationic groups, which facilitate ion transport. Moreover, the crosslinked membranes exhibited excellent alkaline stability, and retained over 65% of hydroxide conductivity in 5 M or 10 M of NaOH at 80 °C for 400 h. It is assumed that crosslinking decreases the water uptake by polymer chain compaction, thus reducing the nucleophilic attack of water or hydroxide at the cationic center. Thus, triazole-containing AEMs with “side-chain-type” architecture appear to be very promising candidates with good stability as high performance anion exchange membrane.