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Abstract Background Selenium supplementation can be used to treat tumors. However, inorganic selenium is highly toxic, and natural organic selenium is extremely rare. Polysaccharides can improve drug bioavailability and targeting. Lentinan is a polysaccharide that has been approved as an anti-cancer drug in Japan and China. Methods Lentinan, an antitumor polysaccharide extracted from Lentinus edodes , was conjugated with seleninic acid to be transformed into ester (Se–lentinan) and utilized as drug carrier. The enhancement of the anti-tumor effects of Se–lentinan was evaluated by cell viability, cell cycle, migration, and transwell assays and animal xenograft models. The effects of Se-lentinan on the expression levels of epithelial–mesenchymal transition (EMT) markers were determined through immunofluorescence, Western blot, and immunohistochemistry analyses. Results Se–lentinan inhibited the invasiveness of B16-BL6 and HCT-8 cells by suppressing EMT. In vivo, Se–lentinan significantly inhibited tumor growth and metastasis of the transplanted melanoma and colon cancer cells and showed less toxicity than sodium selenite. Moreover, Se–lentinan reduced the accumulation of selenium in the liver and kidney tissues of mice and exhibited low organ toxicity. Conclusion The antitumor activity of selenium was enhanced greatly, and its side effects were reduced with the use of lentinan as drug carrier. Highlights • Lentinan was utilized as a drug carrier. • Se-lentinan inhibited the invasion abilities and growths of Melanoma. • Se-lentinan inhibited tumor growth and metastasis with less toxicity. • Se-lentinan reduced the accumulation of selenium in the tissues of mice. [ABSTRACT FROM AUTHOR]

We investigated the speciation of trace metals and their ecological risks to macrobenthic communities in a recovering coastal wetland of China's Yellow River Delta during the freshwater release project. We established 16 sampling sites in three restoration areas and one intertidal reference area, and collected sediments and macrobenthos four times from 2014 to 2015. The instability index for the trace metals showed a moderate risk for Mn and a high risk for Cd. For both Mn and Cd, the carbonate and Fe Mn-bound fractions appear to contribute mostly to the instability and bioavailability indexes, but for Cd, the exchangeable fraction also have a much higher contribution. The bioavailability index indicated higher bioavailability of trace metals in freshwater restoration areas than that in the intertidal area. The single-factor contamination index indicated that most trace metal concentrations in the macrobenthos were in excess of the national standard. The biota-sediment accumulation factor suggested that the macrobenthos accumulated most As, Cd, and Cu. Redundancy analysis showed clear relationships between the macrobenthos and sediment metal concentrations. Our results will help wetland managers to assess the bioaccumulation risks based on metal speciation, and to improve management of these recovering freshwater wetland ecosystems. [ABSTRACT FROM AUTHOR]