Résumé
AIM:To investigate the effect of Eph receptor A2 (EphA2) on drug resistance of colorectal carci-noma cells and its possible mechanisms .METHODS:Real-time PCR and Western blot were used to detect the expression of EphA2 at mRNA and protein levels in LoVo and LoVo/5-FU cells.EphA2 siRNA was transfected to down-regulate the EphA2 expression in LoVo/5-FU cells, and the drug sensitivity was calculated by CCK-8 assay.Meanwhile, cell migration and invasion were measured by wound healing assay and Transwell assay , and the protein levels of E-cadherin,β-catenin, N-cadherin, vimentin, Notch and Snail were determined by Western blot .RESULTS: The expression of EphA2 at both mRNA and protein levels was significantly up-regulated in LoVo/5-FU cells (P<0.05).Knockdown of EphA2 suppressed the cell viability, and migration and invasion abilities , but promoted drug sensitivity of LoVo/5-FU cells.Up-regulation of E-cadherin and β-catenin, and down-regulation of N-cadherin and vimentin were observed , indicating that the epithelial-mesenchymal transition ( EMT) process was suppressed .Knockdown of EphA2 decreased the expression levels of Notch and Snail.CONCLUSION:Down-regulation of EphA2 partly reverses drug resistance of LoVo/5-FU cells.The mechanism may be related to suppressing cell growth , migration, invasion and EMT process via Notch/Snail signaling pathway .
Résumé
Phenolic compounds, the most abundant secondary metabolites in plants, have received more and more attention in recent years because of their distinct bioactivities. This review summarizes different types of phenolic compounds and their extraction and analytical methods used in the recent reports, involving 59 phenolic compounds from 52 kinds of plants. The extraction methods include solid-liquid extraction, ultrasound-assisted extractions, microwave-assisted extractions, supercritical fluid extraction, and other methods. The analysis methods include spectrophotometry, gas chromatography, liquid chromatography, thin-layer chromatography, capillary electrophoresis, and near-infrared spectroscopy. After illustrating the specific conditions of the analytical methods, the advantages and disadvantages of each method are also summarized, pointing out their respective suitability. This review provides valuable reference for identification and/or quantification of phenolic compounds from natural products.