Neurofibromin Deficiency and Extracellular Matrix Cooperate to Increase Transforming Potential through FAK-Dependent Signaling

Simple SummaryNeurofibromatosis type 1 is a genetic disease that predisposes to tumors of the nervous system, primarily the neurofibroma. Plexiform neurofibromas (Pnfs) are of the greatest concern because of location, size, and frequent progression to malignancy. Although research is making great progress, the lack of in-depth understanding of the molecular mechanisms driving neoplastic progression results in the absence of prognostic indicators and therapeutic targets. We document that cell-cell cooperativity and the dynamics of the extracellular matrix play important roles in the growth and transformation of Pnf cells, directly through the cooperation of RAS and focal adhesion kinase (FAK) signaling. In turn, we found that treatment of Pnf cells with both MEK and FAK inhibitors is effective in abolishing the transforming ability of these cells.Plexiform neurofibromas (Pnfs) are benign peripheral nerve sheath tumors that are major features of the human genetic syndrome, neurofibromatosis type 1 (NF1). Pnfs are derived from Schwann cells (SCs) undergoing loss of heterozygosity (LOH) at the NF1 locus in an NF1(+/-) milieu and thus are variably lacking in the key Ras-controlling protein, neurofibromin (Nfn). As these SCs are embedded in a dense desmoplastic milieu of stromal cells and abnormal extracellular matrix (ECM), cell-cell cooperativity (CCC) and the molecular microenvironment play essential roles in Pnf progression towards a malignant peripheral nerve sheath tumor (MPNST). The complexity of Pnf biology makes treatment challenging. The only approved drug, the MEK inhibitor Selumetinib, displays a variable and partial therapeutic response. Here, we explored ECM contributions to the growth of cells lacking Nfn. In a 3D in vitro culture, NF1 loss sensitizes cells to signals from a Pnf-mimicking ECM through focal adhesion kinase (FAK) hyperactivation. This hyperactivation correlated with phosphorylation of the downstream effectors, Src, ERK, and AKT, and with colony formation. Expression of the GAP-related domain of Nfn only partially decreased activation of this signaling pathway and only slowed down 3D colony growth of cells lacking Nfn. However, combinatorial treatment with both the FAK inhibitor Defactinib (VS-6063) and Selumetinib (AZD6244) fully suppressed colony growth. These observations pave the way for a new combined therapeutic strategy simultaneously interfering with both intracellular signals and the interplay between the various tumor cells and the ECM

Soil respiration and nitrogen mineralization kinetics of compost and vinasse fertilized soil in an aerobic liquid-based incubation.

The assessment of soil respiration and nitrogen (N) mineralization under the addition of organic fertilizers is a matter of ever increasing interest. Aiming at a deeper insight into the subject, an aerobic liquid-based incubation was set up for the coupled respiration and N-mineralization over 360 h in a closed system, comparing one compost and one vinasse at rates of 300 and 600 mg N/kg soil, plus an unfertilized control. The system allowed the manometric measurement of themicrobial activity, and the N-mineralization in the suspension via solely NH4-N determination. A set of substrate-induced respiration (SIR) tests was run to investigate the effects of nutrients and nutrients glucose addition on the soil respiration and N-mineralization of the five fertilizer treatments, in comparison with basal respiration in water. In water, compost showed a total net N-mineralization of +0.7 and -6.3% at the low (C1) and high (C2) dose respectively, whereas vinasse nominally reached 100% for both doses (V1 and V2). Soil respiration ranged between 3,269 and 18,389mg O2/kg dry soil of the unfertilized and V2. SIR tests showed that the respiration of compost-treated soil was boosted by nutrients in C2 more than in C1. Conversely, C1 was boosted by nutrients+glucose more than C2, indicating a combined of a nutrient- and carbon dose-dependent mechanism. These findings were confirmed by the N-mineralization, because C2 consumed almost threefold the NH4-N added to the system compared to C1. Vinasse-fertilized soil received a similar benefit from nutrients and nutrients+glucose. The additions of inducing substrates showed how compost and vinasse respiration are dose dependent: the lower the dose, the higher the respiration relative to the amount of added carbon in a carbon starved system. The incubation method adopted here appears to be a valid and rapid tool in the study of the effects of energy and nutrient constraints on respiration and N-mineralization dynamics in soils amended with biosolids

A multivariate approach to the study of the composting process by means of analytical electrofocusing.

Three blends formed by: agro-industrial waste, wastewater sewage sludge, and their mixture, blended with tree pruning as bulking agent, were composted over a 3-month period. During the composting process the blends were monitored for the main physical and chemical characteristics. Electrofocusing (EF) was carried out on the extracted organic matter. The EF profiles were analyzed by principal component analysis (PCA) in order to assess the suitability of EF to evaluate the stabilisation level during the composting process. Throughout the process, the blends showed a general shifting of focused bands, from low to high pH, even though the compost origin affected the EF profiles. If the EF profile is analyzed by dividing it into pH regions, the interpretation of the results can be affected by the origin of compost. A good clustering of compost samples depending on the process time was obtained by analyzing the whole profile by PCA. Analysis of EF results with PCA represents a useful analytical technique to study the evolution and the stabilisation of composted organic matter

La ricerca agronomica in agricoltura biologica

Field-crop research in organic farming is aimed as in conventional farming, at enhancing the effective use of land, labour and energy in achieving a desired output, while saving unnecessary, often non-renewable resources. A vast review of literature is available on the subject for organic crop science, often covering the same topics as in conventional one. More to that, organic cropping has stimulated the development of such tools as agro-ecological indicators and systems of environmental accountancy, which are progressively being extended to the evaluation of conventional cropping systems. In the present paper, the research is focused on a two-year rotation of feed crops, barley and soybean, as the first element of an organic food chain ranging from the field to the animal-based human food. Each crop\u2019s most significant issue in organic farming was investigated: nitrogen nutrition in the cereal; weed control in the late-developing grain leguminous. The two fertilizers tested for barley, a compost of agro-industrial residues and a vinasse of distilled molasses, had a contrasting effect in the second year of trials, when the latter boosted plant biomass but also its sensitivity to a fungal disease, which in turn depressed grain yield at harvest. The problem of weeds in soybean was investigated by means of two sowing times some 15 days apart, each coupled with timely tillage in pre-seeding (harrowing) and in post-emergence (inter-row hoeing). In the first, hot and dry year, the later seeding incurred in a serious plant stress and in a very low yield at harvest. In the second, cool year, a much larger weed population was better controlled in the late seeding thanks to arrowing just prior to sowing. The inter-row hoeing provided a useful support in controlling residual weeds in the early seeding, quite negligible in the late one. On concluding, it is perceived as the farmer\u2019s skill and knowledge are the key factors of success in organic cropping, since fewer means are available to tackle unexpected problems than in conventional cropping

Evolution of organic matter from sewage sludge and yard trimming during composting.

To use compost appropriately in agriculture it is extremely important to estimate the stabilization level of the organic matter. In this work, two different piles of compost were studied by means of (i) humification parameters (degree of humification\u2013\u2013DH, humification rate\u2013\u2013HR, humification index\u2013\u2013HI) prior to and after enzymatic hydrolysis of the extracted organic carbon, (ii) watersoluble organic carbon (WSOC) and (iii) water-soluble nitrogen. A significant relationship between composting time, WSOC and humification parameters after enzymatic hydrolysis (DHenz; HRenz; HIenz) was found. 2003 Elsevier Ltd. All rights reserved