BET inhibitors induce apoptosis through a MYC independent mechanism and synergise with CDK inhibitors to kill osteosarcoma cells

Osteosarcoma (OS) survival rates have plateaued in part due to a lack of new therapeutic options. Here we demonstrate that bromodomain inhibitors (BETi), JQ1, I-BET151, I-BET762, exert potent anti-tumour activity against primary and established OS cell lines, mediated by inhibition of BRD4. Strikingly, unlike previous observations in long-term established human OS cell lines, the antiproliferative activity of JQ1 in primary OS cells was driven by the induction of apoptosis, not cell cycle arrest. In further contrast, JQ1 activity in OS was mediated independently of MYC downregulation. We identified that JQ1 suppresses the transcription factor FOSL1 by displacement of BRD4 from its locus. Loss of FOSL1 phenocopied the antiproliferative effects of JQ1, identifying FOSL1 suppression as a potential novel therapeutic approach for OS. As a monotherapy JQ1 demonstrated significant anti-tumour activity in vivo in an OS graft model. Further, combinatorial treatment approaches showed that JQ1 increased the sensitivity of OS cells to doxorubicin and induced potent synergistic activity when rationally combined with CDK inhibitors. The greater level of activity achieved with the combination of BETi with CDK inhibitors demonstrates the efficacy of this combination therapy. Taken together, our studies show that BET inhibitors are a promising new therapeutic for OS

Primary succession of nitrogen cycling microbial communities along the deglaciated forelands of Tianshan Mountain, China

Structural succession and its driving factors for nitrogen (N) cycling microbial communities during the early stages of soil development (0-44 years) were studied along a chronosequence in the glacial forelands of the Tianshan Mountain No.1 glacier in the arid and semi-arid region of central Asia. We assessed the abundance and population of functional genes affiliated with N-fixation (nifH), nitrification (bacterial and archaeal amoA), and denitrification (nirK/S and nosZ) in a glacier foreland using molecular methods. The abundance of functional genes significantly increased with soil development. N cycling community compositions were also significantly shifted within 44 years and were structured by successional age. Cyanobacterial nifH gene sequences were the most dominant N fixing bacteria and its relative abundance increased from 56.8-93.2% along the chronosequence. Ammonia-oxidizing communities shifted from the Nitrososphaera cluster (AOA-amoA) and the Nitrosospira cluster ME (AOB-aomA) in younger soils (0 and 5 years) to communities dominated by soil and sediment 1 (AOA-amoA) and Nitrosospira Cluster 2 Related (AOB-aomA) in older soils (=17 years). Most of the denitrifers closest relatives were potential aerobic denitrifying bacteria, and some other types of denitrifying bacteria (like autotrophic nitrate-reducing, sulfide-oxidizing bacteria and denitrifying phosphorus removing bacteria) were also detected in all soil samples. The regression analysis showed that N cycling microbial communities were dominant in younger soils (0-5 years) and significantly correlated with soil total carbon, while communities that were most abundant in older soils were significantly correlated with soil total nitrogen. These results suggested that the shift of soil C and N contents during the glacial retreat significantly influenced the abundance, composition and diversity of N cycling microbial communities. © 2016 Zeng, Lou, Zhang, Wang, Hu, Shen, Zhang, Han, Zhang, Lin, Chalk and He

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

An overview of the role and significance of 15N methodologies in quantifying biological N2 fixation (BNF) and BNF dynamics in agro-ecosystems

Quantitative estimates of BNF are needed to improve our understanding of the ecology of N in the environment and aid efforts to improve agricultural N management. Static models based on the principle of 15N isotope dilution have been proposed to estimate the proportion of N in a N2-fixing species that is derived from the atmosphere via biological N2 fixation. Furthermore, equations have been developed to quantify the movement of biologically fixed N between neighboring species or from legumes to cereals in crop rotations. The present paper is structured to provide a comprehensive overview of these methods in a logical and systematic manner. While the relevant literature is vast, some aspects have fortunately been covered by recent in-depth reviews which will be identified and briefly summarized. The overview will emphasize the more practical indirect methodologies based either on artificial 15N enrichment or 15N depletion, or alternatively on 15N natural abundance. In considering methods used to estimate symbiotic dependence, the major structural division is whether or not a non-N2-fixing reference plant is employed, and approaches taken to remove this source of error are described. Four examples are provided to illustrate the contemporary success of 15N-based methods, one in basic research involving endophytic BNF, and three in applied research involving legume breeding for enhanced BNF, the response of legumes to climate change and biotic and abiotic factors affecting legume symbiotic performance

Fate and efficiency of 15 N-labelled slow- and controlled-release fertilizers

Slow- and controlled-release N fertilizers are designed to increase efficiency and reduce N losses by better synchronizing N availability with plant demand. This paper reviews the use of 15N with these fertilizers to collect quantitative data on the efficiency, residual value and N losses for which relatively few data are available compared with conventional labelled urea and ammonium-based fertilizers. In general, studies of slow-release forms (isobutylidene diurea, oxamide, ureaform) with rice and upland crops show one or more benefits, including improved N uptake efficiency, and reduced N losses via leaching or NH3 volatilization under conditions which favor such losses (coarse textured soils, alkaline pH, respectively). Benefits from residual 15N may accrue in the year following application. Studies with controlled-release 15N-labelled sulfur coated urea (SCU) show benefits in situations such as paddy soils where losses from broadcast urea are a substantial problem. In experiments with 15N polyolefin-coated urea (POCU), rice plant recovery of broadcast conventional urea or ammonium salts ranged from 24 % with losses of 50–45 % with losses of 33 %. Where 15N labelled SCU or POCU was used, the rice recovery ranged from 26 % with losses of 14–72 % with losses of 10 %. Experiments using POCU with corn, barley and potato show similar results. The paucity of published data obtained using 15N points to the need for further studies that will provide concrete evidence for the development of innovative fertilizers with enhanced efficiency and an evidence-based set of recommendations for their selection and use

The relative isotopic abundance (<i>δ</i>¹³C, <i>δ</i>¹⁵N) during composting of agricultural wastes in relation to compost quality and feedstock

<p>Variations in the relative isotopic abundance of C and N (<i>δ</i>¹³C and <i>δ</i>¹⁵N) were measured during the composting of different agricultural wastes using bench-scale bioreactors. Different mixtures of agricultural wastes (horse bedding manure + legume residues; dairy manure + jatropha mill cake; dairy manure + sugarcane residues; dairy manure alone) were used for aerobic–thermophilic composting. No significant differences were found between the <i>δ</i>¹³C values of the feedstock and the final compost, except for dairy manure + sugarcane residues (from initial ratio of −13.6 ± 0.2 ‰ to final ratio of −14.4 ± 0.2 ‰). <i>δ</i>¹⁵N values increased significantly in composts of horse bedding manure + legumes residues (from initial ratio of +5.9 ± 0.1 ‰ to final ratio of +8.2 ± 0.5 ‰) and dairy manure + jatropha mill cake (from initial ratio of +9.5 ± 0.2 ‰ to final ratio of +12.8 ± 0.7 ‰) and was related to the total N loss (mass balance). <i>δ</i>¹³C can be used to differentiate composts from different feedstock (e.g. C₃ or C₄ sources). The quantitative relationship between N loss and <i>δ</i>¹⁵N variation should be determined.</p