Determination of niclosamide and its two metabolites in fish by molecularly imprinted microsphere-based pseudo-ELISA.

Niclosamide is usually used for the treatment of parasite infections in animals. However, niclosamide and one of its metabolites 2-chloro-4-nitroaniline are mutagenic substances, and their residues in animal-derived foods are potential risks to consumers. As far as we know, there has been no immunoassay or pseudo immunoassay reported to determine niclosamide and its metabolites in animal-derived foods. In this study, a molecularly imprinted microsphere for niclosamide was first synthesized, and a streptavidin-horseradish peroxidase labelled conjugate was also synthesized. The two reagents were used to develop a pseudo enzyme-linked immunosorbent assay on conventional microplates for the determination of niclosamide and its two metabolites (2-chloro-4-nitroaniline and 5-chlorosalicylic acid) in fish. Because biotinylated horseradish peroxidase was used to amplify the signal, the method sensitivities for the three analytes were increased fivefold to 27.5-fold (limits of detection of 0.004-0.03 ng/mL) in comparison with the use of single horseradish peroxidase labelled conjugate (limits of detection of 0.11-0.16 ng/mL). Their recoveries from the standards fortified blank fish samples were in the range of 70.6-95.5%. This is the first study reporting a molecularly imprinted polymer-based pseudo immunoassay for screening of niclosamide and its metabolites in food sample.

Caffeic acid phenethyl ester inhibits the progression of ovarian cancer by regulating NF-?B signaling.

Ovarian cancer is one of the most common malignancies in women and characterized by a rapid progression to metastasis, which restricts effective treatment options. Caffeic acid phenethyl ester (CAPE), a natural honeybee product, exhibits a variety of biological activities, anti-tumor is included. Our study aims to explore whether CAPE could inhibit the progression of ovarian cancer and the underlying molecular mechanism. The establishment of ovarian cancer model was set up in mice through caudal vein injection of SKOV-3 cells. Results indicated that CAPE treatment remarkably decreased the viability, migration and invasion of SKOV-3 cells. Besides that, the apoptosis of SKOV-3 cells was significantly promoted by CAPE treatment. Moreover, the growth of ovarian cancer was tremendously inhibited by CAPE in vivo and its action was accompanied by the obstructed Ki67 and PCNA expression. Furthermore, nuclear factor kappa b (NF-?B) pathway was dramatically suppressed by CAPE through the inhibition of I?B phosphorylation, nuclear translocation of p65 and NF-?B p65 DNA binding activity. By contrast, cells transfected with p65 siRNA exhibited decreased cell viability, migration and invasion along with increased cell apoptosis in SKOV-3 cells. However, CAPE treatment could enhance these alters induced by p65 siRNA in KOV-3 cells. Taken together, these findings suggested that CAPE could restrain the progression of ovarian cancer via inactivating NF-?B signaling, and may provide novel therapeutic regimens for ovarian cancer.