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Objective: To investigate the effect of 17-allylamino-demethoxygeldanamycin (17AAG) on the proliferative and invasive ability of gastric cancer cells and associated mechanism., Methods: The proliferative ability was tested by MTT method and the cell cycle was detected by flow cytometry(FCM) when 17AAG was used to treat gastric cancer cell SGC7901. Apoptosis was detected by FCM and PI-Annexin V double staining. The invasive ability was tested by transwell method. Expression of HSP90, HSP70, c-met and AKT was detected by Western blot., Results: The growth of SGC7901 cells was inhibited after the administration of 17AAG, and the inhibitation was dose- and time-dependent. The cell cycle was blocked at the G0/G1 phase. The apoptotic ratio in 17AAG group was much higher than that in blank group and DMSO group (P<0.01). The cellular invasive ability decreased significantly (P<0.01). The expression of HSP70 was elevated by 17AAG, and the expression of c-met and AKT was down-regulated, but no change of HSP90 was observed., Conclusion: 17AAG can inhibit the proliferative and invasive ability of SGC7901 cells, and induces apoptosis through down-regulating the expression of HSP90 client proteins instead of the target HSP90 itself.

A simple and reliable method was developed for simultaneous determination of multi-class antibiotic residues in aquatic environment, including three fluoroquinolones (ofloxacin, norfloxacin, ciprofloxacin), three sulfonamides (sulfadiazine, sulfamethoxazole, sulfamethazine), chloramphenicol and trimethoprim. Samples were extracted and concentrated through hydrophilic-lipophilic balance (HLB) cartridges. Selected antibiotic compounds were determined by high performance liquid chromatography (HPLC) using internal standard quantification method. Antibiotics were separated on an Agilent XRD C18 column (150 mm x 3.0 mm, 3.5 microm) with a gradient elution using acetonitrile and 0.1% (v/v) formic acid in purified water at a flow rate of 0.25 mL/min and the column temperature of 25 degree C. Fluoroquinolones were quantified by fluorescence detection (FLD) and the others by ultraviolet detection at 280 nm. The recoveries for the antibiotics are ranging from 80% to 120% for spiked tap water, and 63% to 106% for urban river water samples, respectively, with relative standard deviation lower than 18%. The limits of quantification were 0.030-0.080 microg/L for surface waters. The method has been successfully applied to monitor the occurrence of antibiotic residues in the urban river waters from the Pearl River in Guangzhou. Sulfamethoxazole, ofloxacin, norfloxacin and ciprofloxacin were detected at mass concentrations ranging from 0.197 to 0.510 microg/L.