New insights on the mechanism of quinoline-based DNA methyltransferase inhibitors

Among the epigenetic marks, DNA methylation is one of the most studied. It is highly deregulated in numerous diseases, including cancer. Indeed, it has been shown that hypermethylation of tumor suppressor genes promoters is a common feature of cancer cells. Because DNA methylation is reversible, the DNA methyltransferases (DNMTs), responsible for this epigenetic mark, are considered promising therapeutic targets. Several molecules have been identified as DNMT inhibitors and, among the non-nucleoside inhibitors, 4-aminoquinoline-based inhibitors, such as SGI-1027 and its analogs, showed potent inhibitory activity. Here we characterized the in vitro mechanism of action of SGI-1027 and two analogs. Enzymatic competition studies with the DNA substrate and the methyl donor cofactor, S-adenosyl-L-methionine (AdoMet), displayed AdoMet non-competitive and DNA competitive behavior. In addition, deviations from the Michaelis-Menten model in DNA competition experiments suggested an interaction with DNA. Thus their ability to interact with DNA was established; although SGI-1027 was a weak DNA ligand, analog 5, the most potent inhibitor, strongly interacted with DNA. Finally, as 5 interacted with DNMT only when the DNA duplex was present, we hypothesize that this class of chemical compounds inhibit DNMTs by interacting with the DNA substrate

Habitat ecological integrity and environmental impact assessment of anthropic activities: A GIS-based fuzzy logic model for sites of high biodiversity conservation interest

In literature, an effective method enabling the classification, based on a single indicator, of habitats that need a priority protection intervention has not been identified yet. Moreover, the excessive number of landscape metrics, used to quantify integrity of habitats, can cause confusion, often providing redundant and inconsistent results. The aim of this work is to develop a method for evaluating the ecological vulnerability of the habitats in sites of high biodiversity conservation interest. In the first phase, we selected and analyzed, by using principal component analysis (PCA) and fuzzy logic, the landscape metrics, in order to obtain the map of the intrinsic ecological vulnerability index. In the second step, the result of this intrinsic vulnerability was connected, through another fuzzy model, to anthropogenic impacts, obtaining the integrated ecological vulnerability index. We developed specific spatial indicators (landscape metrics), which can examine the mutual position and morphology of the habitats present, along with indicators of human pressure, related to the type and intensity of use of the anthropic territory, with reference to the habitat itself as well as to the areas immediately adjacent. The developed fuzzy models are innovative, compared to the current ecological studies, and examine landscape metrics as well as the impact of human activities. The case study is the "Val Basento-Ferrandina Scalo" Site of Community Importance, Ferrandina-SCI (Basilicata Region, Southern Italy). The results allowed us to build a rank of the habitats based on their intrinsic and integrated ecological vulnerability. Moreover, the results show that, in the Ferrandina-SCI, the most important source of concern is not human activities, but rather the inherent risk of ecological fragility caused by geographical and landscape features of the different patches of habitats themselves. This model aims to be a tool for decision support in sustainable landscape management. It is easy to use and to apply on other regions, although it should always be accompanied by a sensitivity analysis to reduce the subjectivity

Wastewater reuse for irrigation of energy crops: CO2 balance in simplified treatment schemes

The objective of this study was the assessment of environmental sustainability of urban wastewater reuse for irrigation of energy crops, by carrying out the balance of CO2 emissions in biological wastewater treatment plants (WWTPs). The proposed innovative scheme is able to remove pathogens and dangerous components for the environment, but it is able to release nutrients useful for fertigation of energy crops. Moreover, it has a significant operational flexibility, which is guaranteed by the possibility of gradually changing the plant configuration passing from the configuration for irrigation of energy crops to that for discharge into receiving water bodies. The innovative feature of this research is the assessment of the budget of climatechanging greenhouse gas emissions (GHG) caused by the simplified treatment for controlled release and reuse of reclaimed wastewater. Numerical simulations were carried out by implementing the ASM1 model. The stoichiometric matrix of the ASM1 model was modified, in order to obtain equivalent emissions of greenhouse gases directly from the mass balance equations. The developed model is able to perform a continuous monitoring of equivalent CO2 emissions from WWTPs. The aim is to assess the evolution of GHG due to changes of possible adopted treatment schemes, and to estimate the amount of emissions. The new controlled-release scheme produces wastewater with high concentrations of fertilizers and nutrients, such as stabilized nitrogen and organic matter, but, at the same time, it minimizes risks for the environment, by reducing the total emissions of equivalent CO2

An Analog of BIX-01294 Selectively Inhibits a Family of Histone H3 Lysine 9 Jumonji Demethylases

BIX-01294 and its analogs were originally identified and subsequently designed as potent inhibitors against histone H3 lysine 9 (H3K9) methyltransferases G9a and G9a-like protein. Here, we show that BIX-01294 and its analog E67 can also inhibit H3K9 Jumonji demethylase KIAA1718 with half-maximal inhibitory concentrations in low micromolar range. Crystallographic analysis of KIAA1718 Jumonji domain in complex with E67 indicated that the benzylated six-membered piperidine ring was disordered and exposed to solvent. Removing the moiety (generating compound E67-2) has no effect on the potency against KIAA1718 but, unexpectedly, lost inhibition against G9a-like protein by a factor of 1500. Furthermore, E67 and E67-2 have no effect on the activity against histone H3 lysine 4 (H3K4) demethylase JARID1C. Thus, our study provides a new avenue for designing and improving the potency and selectivity of inhibitors against H3K9 Jumonji demethylases over H3K9 methyltransferases and H3K4 demethylases. (C) 2011 Elsevier Ltd. All rights reserved

PRMT1 arginine methyltransferase accumulates in cytoplasmic bodies that respond to selective inhibition and DNA damage

Protein arginine methyltransferases (PRMTs) are responsible for symmetric and asymmetric methylation of arginine residues of nuclear and cytoplasmic proteins. In the nucleus, PRMTs belong to important chromatin modifying enzymes of immense functional significance that affect gene expression, splicing and DNA repair. By time-lapse microscopy we have studied the sub-cellular localization and kinetics of PRMT1 after inhibition of PRMT1 and after irradiation. Both transiently expressed and endogenous PRMT1 accumulated in cytoplasmic bodies that were located in the proximity of the cell nucleus. The shape and number of these bodies were stable in untreated cells. However, when cell nuclei were microirradiated by UV-A, the mobility of PRMT1 cytoplasmic bodies increased, size was reduced, and disappeared within approximately 20 min. The same response occurred after γ-irradiation of the whole cell population, but with delayed kinetics. Treatment with PRMT1 inhibitors induced disintegration of these PRMT1 cytoplasmic bodies and prevented formation of 53BP1 nuclear bodies (NBs) that play a role during DNA damage repair. The formation of 53BP1 NBs was not influenced by PRMT1 overexpression. Taken together, we show that PRMT1 concentrates in cytoplasmic bodies, which respond to DNA injury in the cell nucleus, and to treatment with various PRMT1 inhibitors.</p

Assessing the economic suitability of aeration and the influence of bed heating on constructed wetlands treatment efficiency and life-span

Constructed wetlands including aeration and heating were studied to improve treatment efficiency and prevent clogging. The experiments were carried out in a pilot plant (0.4 m(2)) treating urban wastewater with an organic loading rate of 40-60 g COD/m(2) d. Continuous and intermittent aeration was performed from the bottom on 8% of the wetland surface, leading to different dissolved oxygen concentrations within the wetlands (from 0.2 to 5 mg O-2/L). Continuous aeration increased organic matter (COD) and ammonium nitrogen removal by 56% and 69%, respectively. Improvements in wastewater treatment caused by aeration can result in reduction of the surface area requirement of future systems. This work demonstrated that for the studied configuration the cost of the power consumption of the continuous aeration was largely covered by the reduction of the wetlands surface. Even if the heating of 8% of the wetland surface at 21 degrees C had no effects on treatment performance, positive results showed that solids accumulation rate within the granular medium, which is closely related to the development of clogging. It has been demonstrated that heating for 10 days per year during 20 year period would delay the equivalent of 1 year of solids accumulation.Peer Reviewe

1,3,4-Oxadiazole-Containing Histone Deacetylase Inhibitors: Anticancer Activities in Cancer Cells

We describe 1,3,4-oxadiazole-containing hydroxamates (<b>2</b>) and 2-aminoanilides (<b>3</b>) as histone deacetylase inhibitors. Among them, <b>2t</b>, <b>2x</b>, and <b>3i</b> were the most potent and selective against HDAC1. In U937 leukemia cells, <b>2t</b> was more potent than SAHA in inducing apoptosis, and <b>3i</b> displayed cell differentiation with a potency similar to MS-275. In several acute myeloid leukemia (AML) cell lines, as well as in U937 cells in combination with doxorubicin, <b>3i</b> showed higher antiproliferative effects than SAHA