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Accumulating evidences suggest that circular RNAs play vital roles in human cancers. Previously, we found that circHIPK3 suppressed invasion of bladder cancer cells via sponging miR-558 and downregulating heparanase expression. In this study, we discovered that a circular RNA derived from NR3C1 (circNR3C1) was downregulated in bladder cancer tissues and cell lines according to RNA-Seq data and qRT-PCR analysis. Functionally, we found that overexpression of circNR3C1 could significantly inhibit cell cycle progression and proliferation of bladder cancer cells in vitro, as well as suppress tumor growth in vivo. Mechanistically, we demonstrated that circNR3C1 possessed four targeting sites of miR-27a-3p and could effectively sponge miR-27a-3p to suppress the expression of cyclin D1. Furthermore, we revealed that miR-27a-3p functioned as an oncogene through interacting with 5'UTR of cyclin D1 to enhance its expression, which led to promote cell cycle progression and proliferation in bladder cancer cells. Conclusively, our findings further confirm the hypothesis that circRNAs function as "microRNA sponges", and our data suggest that circNR3C1 and miR-27a-3p would be potential therapeutic targets for bladder cancer treatment. [ABSTRACT FROM AUTHOR]

Concentrations of common pollutants in groundwater continue to increase, and emerging pollutants are also increasingly found worldwide, thereby increasingly impacting human activities. In this new situation, it is necessary, albeit more difficult, to once again recognize the hydrochemical genesis of groundwater and to subsequently screen the typical pollutants. Taking the groundwater of the Songnen Plain of Northeast China as an example, the hydrochemical genesis was identified using space interpolation, characteristic element ratio and factor analysis methods based on 368 groundwater samples. Subsequently, the typical pollutants with potential impacts on the health of the local residents were screened by the index system method newly established. All the measured hydrochemical compositions show an obvious spatial variation, with a uniform hydrochemical type of HCO 3 –Ca in the whole area. Both the major compositions (K, Na, Ca, Mg, HCO 3 , Cl and SO 4) and trace compositions (Fe, Mn, Cu, Zn, Pb, As, F, I and Se) are mainly protogenetic in an environment impacted by the lixiviation of groundwater in the migration process in the strata, although these compositions have been impacted by human activities to varying degrees. The mass concentration of NO 3 –N has exceeded most of the major compositions except for HCO 3 and Ca, which means the nitrogen pollution problem is already very serious; and this problem is mainly caused by the utilization of fertilizers and the discharge of industrial wastewater and domestic sewage. Human activities have obviously disrupted the natural dynamic balance of these chemicals between the environment and the groundwater, thereby intensifying the release of F, Fe and Mn from the environment. TDS, total hardness, tri-nitrogen, F, Fe, Mn, Pb and As in some parts are found to exceed the standards of groundwater quality to varying degrees. As, Pb, Fe, NO 3 –N, NO 2 –N, Mn, F and NH 4 –N are finally screened as the typical pollutants. Image 1 • Three methods were used to determine hydrochemical genesis and typical pollutants. • A index system model for screening typical groundwater pollutants was constructed. • The influencing factors of hydrochemical genesis were analyzed. • The groundwater pollution situation was compared horizontally and vertically. • Reliable suggestions were provided for regional groundwater management. This work identified the hydrochemical genesis and screened the typical pollutants in Songnen Plain groundwater. [ABSTRACT FROM AUTHOR]

The groundwater in many aquifers contains elevated concentrations of iron (Fe). Although much of this Fe is from its release from water-bearing sediments under natural environmental conditions, sufficient evidence is lacking to clarify whether anthropogenic pollutants, such as dissolved organic matter (DOM), can increase this natural release. In this time series and comparative analysis study, an Fe increasing effect was verified through laboratory leaching tests. The influences of the aqueous environmental conditions, such as pH, were also investigated. DOM can promote the release of Fe from sediments and increase the concentration of Fe in groundwater. In addition, lower or higher pH and temperature can enhance the release of Fe to some extent. Higher concentrations of DOM provided a more thorough release of Fe from the sediment; additional ions such as Cu also affected Fe release. It is possible that complexation between DOM and Fe occurs through ligand dissolution and reduction, thus promoting the release of Fe. The findings indicate that DOM imported through anthropogenic activities can increase the release of Fe from aquifer sediments into groundwater, thus worsening Fe pollution in groundwater. This study explored the mechanism by which different types of DOM release Fe from aquifer sediments and investigated the factors that influence this process. The findings provide insights into the geochemical processes of Fe in the groundwater. [Display omitted] • DOM in groundwater increases Fe release from aquifer sediment. • Physicochemical conditions of groundwater and sediment determine Fe leaching. • The mechanism by which DOM releases Fe has multiple synergistic aspects. • Fe leaching in aquifers involves complex geochemical processes. • Anthropogenic organic pollution strongly affects Fe geochemical processes. [ABSTRACT FROM AUTHOR]