A novel water-soluble beta-cyclodextrin (β-CD)-functionalized ZnS quantum dot (QD)–neutral red (NR) fluorescence resonance energy transfer (FRET) probe for the selective determination of the concentration of megestrol acetate in river water has been developed. The water-soluble and low-toxicity β-CD-functionalized ZnS QDs were first synthesized, and their characterization was confirmed by transmission electron microscopy and infrared, UV-vis and fluorescence emission spectra. The NR molecule can enter the cavity of the β-CD anchored onto the surfaces of the ZnS QDs in its neutral form, forming the FRET probe. Compared with other steroid hormones, the probe can selectively recognize megestrol acetate at a lower concentration level. The possible underlying mechanism of the probe with nine steroid hormones was discussed in detail. The fluorescence quenching fractions of the probe presented a satisfactory linearity with the concentrations of megestrol acetate, and its limit of detection was calculated to be 0.0083 μM. Coupled with sample pretreatment procedures, the probe has been applied to the determination of megestrol acetate in river water. The average recoveries of megestrol acetate in the spiking levels of 0.001 μM–10 μM ranged from 97% to 110% with a relative standard deviation below 15%, which was similar to those for HPLC or MS techniques.
Zheng Ning,Liu Weiqun,Li Bifei,Nie Huifang,Liu Jian,Cheng Yunlong,Wang Jichuang,Dong Haiyan,Jia Lee
Background Sorafenib is approved as a standard therapy for advanced hepatocellular carcinoma (HCC), but its clinical application is limited due to moderate therapeutic efficacy and high incidence of acquired resistance resulted from elevated levels of SDF-1/CXCR4 axis induced by prolonged sorafenib treatment. We previously demonstrated metapristone (RU486 metabolite) as a cancer metastatic chemopreventive agent targeting SDF-1/CXCR4 axis. Therefore, we hypothesized that combining sorafenib with metapristone could synergistically suppress cell proliferation, enhance anti-cancer activity and repress potential drug resistance. Methods Changes in cellular CXCR4 expression by metapristone were analyzed by RT-PCR and western blotting. Effect of combining sorafenib with metapristone on cell viability was examined by MTT assay; combination index value was calculated to evaluate the synergistic effect of combined therapy. To overcome poor pharmacokinetics and reduce off-target toxicity, CXCR4-targeted nanoparticles (NPs) were developed to co-deliver sorafenib and metapristone into CXCR4-expressing HCC in vitro and in vivo; cell proliferation, colony formation and apoptosis assays were conducted; nude mice bearing HCC xenograft were used to examine effects of this therapeutic approach on HCC progression. Results Here we showed metapristone significantly reduced CXCR4 expression in HCC. Combinatory chemotherapy of sorafenib with metapristone synergistically suppressed HCC proliferation and resistance. CXCR4-targeted PEGylated poly (lactic-co-glycolic acid) NPs conjugated with LFC131 (a peptide inhibitor of CXCR4), could deliver more sorafenib and metapristone into HCC via specific recognition and binding with transmembrane CXCR4, and resulted in the enhanced cytotoxicity, colony inhibition and apoptosis by regulating more Akt/ERK/p38 MAPK/caspase signaling pathways. Co-delivery of sorafenib with metapristone by the LFC131-conjugated NPs showed prolonged circulation and target accumulation at tumor sites, and thus suppressed tumor growth in a tumor xenograft model. Conclusions In conclusion, co-delivery of sorafenib and metapristone via the CXCR4-targeted NPs displays a synergistic therapy against HCC. Our results suggest combinational treatment of chemotherapeutics offer an effective strategy for enhancing the therapeutic efficacy on carcinoma, and highlight the potential application of ligand-modified tumor-targeting nanocarriers in delivering drugs as a promising cancer therapeutic approach.
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