The direct impact of pegvisomant on osteoblast functions and bone development.

PURPOSE: Acromegaly is a chronic disease characterized by growth hormone (GH) hypersecretion, usually caused by a pituitary adenoma, resulting in elevated circulating levels of insulin-like growth factor type I (IGF-I). Pegvisomant (PEG), the GH-receptor (GHR) antagonist, is used in treating acromegaly to normalize IGF-I hypersecretion. Exposure to increased levels of GH and IGF-I can cause profound alterations in bone structure that are not completely reverted by treatment of GH hypersecretion. Indeed, there is evidence that drugs used for the treatment of acromegaly might induce direct effects on skeletal health regardless of biochemical control of acromegaly. METHODS: We investigated, for the first time, the effect of PEG on cell proliferation, differentiation, and mineralization in the osteoblast cell lines MC3T3-E1 and hFOB 1.19 and its potential impact on bone development in zebrafish larvae. RESULTS: We observed that PEG did not affect osteoblast proliferation, apoptosis, alkaline phosphatase (ALP) activity, and mineralization. After PEG treatment, the analysis of genes related to osteoblast differentiation showed no difference in Alp, Runx2, or Opg mRNA levels in MC3T3-E1 cells. GH significantly decreased cell apoptosis (- 30 ± 11%, p < 0.001) and increased STAT3 phosphorylation; these effects were suppressed by the addition of PEG in MC3T3-E1 cells. GH and PEG did not affect Igf-I, Igfbp2, and Igfbp4 mRNA levels in MC3T3-E1 cells. Finally, PEG did not affect bone development in zebrafish larvae at 5 days post-fertilization. CONCLUSION: This study provides a first evidence of the impact of PEG on osteoblast functions both in vitro and in vivo. These findings may have clinically relevant implications for the management of skeletal health in subjects with acromegaly.

Pancreatic neuroendocrine tumor progression and resistance to everolimus: the crucial role of NF-kB and STAT3 interplay.

PURPOSE: The finding of mTOR overactivation in patients affected by pancreatic neuroendocrine tumors (Pa-NETs) led to their treatment with the mTOR inhibitor everolimus. Unfortunately, the efficacy of everolimus is restricted by the occurrence of resistance. The mechanisms leading to Pa-NETs' progression and resistance are not well understood. Notably, chronic inflammation is implicated in NET development. NF-kB is involved in inflammation and drug resistance mechanisms through the activation of several mediators, including STAT3. In this respect, NF-κB and STAT3 interaction is implicated in the crosstalk between inflammatory and tumor cells. METHODS: We investigated the expression of NF-kB in different Pa-NETs by RT-qPCR and immunohistochemistry. Then, we studied the role of NF-κB and STAT3 interplay in QGP-1 cells. Subsequently, we assessed the impact of NF-κB and STAT3 inhibitors in QGP-1 cell proliferation and spheroids growth. Finally, we evaluated the implication of the NF-kB pathway in everolimus-resistant Pa-NET cells. RESULTS: We found that the increased NF-kB expression correlates  with a higher grade in Pa-NETs. The activation of the STAT3 pathway induced by TNFα is mediated by NF-kB p65. NF-kB p65 and STAT3 inhibitors decrease QGP-1 viability, spheroids growth, and Pa-NETs cell proliferation. These effects are maintained in everolimus-resistant QGP-1R cells. Interestingly, we found that NF-kB, STAT3, IL-8, and SOCS3 are overexpressed in QGP-1R compared to QGP-1. CONCLUSION: Since the NF-kB pathway is implicated in Pa-NETs' progression and resistance to everolimus, these data could explain the potential use of NF-kB as a novel therapeutic target in Pa-NET patients.

Evaluation of Uncertainties in the Anthropogenic SO2 Emissions in the USA from the OMI Point Source Catalog.

Satellite remote sensing is a promising method of monitoring emissions that may be missing in inventories, but the accuracy of these estimates is often not clear. We demonstrate here a comprehensive evaluation of errors in anthropogenic sulfur dioxide (SO2) emission estimates from NASA's OMI point source catalog for the contiguous US by comparing emissions from the catalog with high-quality emission inventory data over different dimensions including size of individual sources, aggregate vs individual source errors, and potential bias in individual source estimates over time. For sources that are included in the catalog, we find that errors in aggregate (sum of error for all included sources) are relatively low. Errors for individual sources in any given year can be substantial, however, with over- or underestimates in terms of total error ranging from -80 to 110 kt (roughly 10-90th percentile). We find that these errors are not necessarily random over time and that there can be consistently positive or negative biases for individual sources. We did not find any overall statistical relationship between the degree of isolation of a source and bias, either at a 40 or 70 km scales. For a sub-set of sources where inventory emissions over a radius of 70 km around an OMI detection are larger than twice the emissions within 40 km, the OMI value is consistently overestimated. We find, as expected, that emission sources not included in the catalog are the largest aggregate source of difference between the satellite estimates and inventories, especially in more recent years where source emission magnitudes have been decreasing and note that trends in satellite detections do not necessarily track trends in total emissions. We find that the OMI-based SO2 emissions are accurate in aggregate, when summed over a number of sources, but must be interpreted more cautiously at the individual source level. Similar analyses would be valuable for other satellite emission estimates; however, in many cases, the appropriate high-quality reference data may need to be generated.

Direct effects of octreotide on osteoblast cell proliferation and function.

PURPOSE: Octreotide (OCT) is a first-generation somatostatin analog (SSA) used in the treatment of acromegaly and neuroendocrine tumors (NETs). In both diseases, OCT interacts with somatostatin receptors 2 and 5 (SSTR2 and SSTR5), inhibiting hormone hypersecretion and cell proliferation. Skeletal health is an important clinical concern in acromegaly and NETs, since acromegalic osteopathy and NET bone metastasis occur in a remarkable number of patients. While OCT's effect on NET and pituitary cells has been extensively investigated, its direct action on bone cells remains unknown. METHODS: Here, we investigated OCT direct effects on cell proliferation, differentiation, mineralization, and chemoattractant capacity of murine primary osteoblasts and osteoblast cell line MC3T3-E1. RESULTS: OCT inhibited osteoblasts and MC3T3-E1 cell proliferation (- 30 ± 16%, and - 22 ± 4%, both p < 0.05 vs control) and increased MC3T3-E1 cell apoptosis (+ 76 ± 32%, p < 0.05 vs control). The anti-proliferative action of OCT was mediated by SSTR2 and SSTR5 in MC3T3-E1, while its pro-apoptotic effect was abrogated in SSTR2-silenced cells. The analysis of genes related to the early and late phases of osteoblast differentiation showed that OCT did not affect Alp, Runx2, Bglap, Spp1, and Sost levels in MC3T3-E1 cells. Similarly, OCT did not affect ALP activity, mineralization, and osteoclastogenic induction. Finally, Vegfa expression decreased in OCT-treated MC3T3-E1 cells and OCT inhibited pancreatic NET cell migration toward the osteoblast-conditioned medium. CONCLUSION: This study provides the first evidence of the direct action of OCT on osteoblasts which may have clinically relevant implications for the management of skeletal health in subjects with acromegaly and metastatic NETs.

The impact of SST2 trafficking and signaling in the treatment of pancreatic neuroendocrine tumors.

Pancreatic neuroendocrine tumors (Pan-NETs), are heterogeneous neoplasms, whose incidence and prevalence are increasing worldwide. Pan-NETs are characterized by the expression of somatostatin receptors (SSTs). In particular, SST2 is the most widely distributed SST in NETs, thus representing the main molecular target for somatostatin analogs (SSAs). SSAs are currently approved for the treatment of well-differentiated NETs, and radionuclide-labeled SSAs are used for diagnostic and treatment purposes. SSAs, by binding to SSTs, have been shown to inhibit hormone secretion and thus provide control of hypersecretion symptoms, when present, and inhibit tumor proliferation. After SSA binding to SST2, the fate of the receptor is determined by trafficking mechanisms, crucial for the response to endogenous or pharmacological ligands. Although SST2 acts mostly through G protein-dependent mechanism, receptor-ligand complex endocytosis and receptor trafficking further regulate its function. SST2 mediates the decrease of hormone secretion via a G protein-dependent mechanism, culminating with the inhibition of adenylyl cyclase and calcium channels; it also inhibits cell proliferation and increases apoptosis through the modulation of protein tyrosine phosphatases. Moreover, SST2 inhibits angiogenesis and cell migration. In this respect, the cross-talk between SST2 and its interacting proteins, including Filamin A (FLNA) and aryl hydrocarbon receptor-interacting protein (AIP), plays a crucial role for SST2 signaling and responsiveness to SSAs. This review will focus on recent studies from our and other groups that have investigated the trafficking and signaling of SST2 in Pan-NETs, in order to provide insights into the mechanisms underlying tumor responsiveness to pharmacological treatments.

A novel insight into the anticancer mechanism of metformin in pancreatic neuroendocrine tumor cells.

The antidiabetic drug metformin displays anticancer properties in several neoplasms. In pituitary NETs, aryl hydrocarbon receptor-interacting protein (AIP) is up-regulated by the somatostatin analog octreotide. Metformin inhibited QGP-1 cell proliferation in a dose- and time-dependent manner, at concentrations similar to those achievable in treated patients (-31 ± 12%, p < 0.05 vs basal at 100 µM). Moreover, metformin decreased pancreatic neuroendocrine tumors (PAN-NETs) cell proliferation (-62 ± 15%, p < 0.0001 vs basal at 10 mM), without any additive effect when combined with octreotide. Both octreotide and metformin induced AIP up-regulation. AIP silencing abolished the reduction of mTOR phosphorylation induced by metformin and octreotide. Moreover, metformin decreased HSP70, increased Zac1 and AhR expression; these effects were abolished in AIP silenced QGP-1 cells. In conclusion, metformin acts as an anticancer agent in PAN-NET cells, its activity is mediated by AIP and its interacting proteins. These findings provide a novel insight into the antitumorigenic mechanism of metformin.

Record-Breaking Increases in Arctic Solar Ultraviolet Radiation Caused by Exceptionally Large Ozone Depletion in 2020.

Measurements of solar ultraviolet radiation (UVR) performed between January and June 2020 at 10 Arctic and subarctic locations are compared with historical observations. Differences between 2020 and prior years are also assessed with total ozone column and UVR data from satellites. Erythemal (sunburning) UVR is quantified with the UV Index (UVI) derived from these measurements. UVI data show unprecedently large anomalies, occurring mostly between early March and mid-April 2020. For several days, UVIs observed in 2020 exceeded measurements of previous years by up to 140%. Historical means were surpassed by more than six standard deviations at several locations in the Arctic. In northern Canada, the average UVI for March was about 75% larger than usual. UVIs in April 2020 were elevated on average by about 25% at all sites. However, absolute anomalies remained below 3.0 UVI units because the enhancements occurred during times when the solar elevation was still low.

An Analysis of Factors Associated with 25-Hydroxyvitamin D Levels in White and Non-White Canadians.

Vitamin D status was assessed in 19-79 year old whites (8351 participants of European ancestry) and non-whites (1840 participants encompassing all other ancestries) from cycles 1 to 3 (years 2007-2013) of the Canadian Health Measures Survey. Status was assessed using the U.S. Institute of Medicine (IOM) 25-hydroxyvitamin D [25(OH)D] cut point values of 30 and 40 nmol/L. Overall, median 25(OH)D concentrations were significantly higher in whites [58.9 (28.6, 100.1) nmol/L; 5th and 95th percentile] compared with non-whites [43.5 (19.0, 83.2); P < 0.001]. Values were higher in females [58.5 (27.5, 101.3) nmol/L] when compared with males [53.5 (24.2, 92.7) nmol/L] and increased with age. Non-whites were more likely to have 25(OH)D values below IOM established cut points for optimum bone health with 20.1 (16.0, 24.2) and 42.2% (36.8, 47.7) of non-whites having serum 25(OH)D concentrations <30 and <40 nmol/L, respectively. The corresponding values for whites were 5.9 (4.6, 7.2) and 16.1% (14.0, 18.3). Values were lower during the first quarter when compared with the third quarter. Supplement intake was an important factor in determining 25(OH)D levels, but it did not alone account for the difference in status. Equivalent increases in 25(OH)D levels were observed in whites and non-whites during the summer months, suggesting there was no functional difference in sun exposure response. It is apparent that a complex interaction of factors affect 25(OH)D values in free-living Canadians.

One-Dimensional Liquid

We compute the zero-temperature dynamical structure factor of one-dimensional liquid ^{4}He by means of state-of-the-art quantum Monte Carlo and analytic continuation techniques. By increasing the density, the dynamical structure factor reveals a transition from a highly compressible critical liquid to a quasisolid regime. In the low-energy limit, the dynamical structure factor can be described by the quantum hydrodynamic Luttinger-liquid theory, with a Luttinger parameter spanning all possible values by increasing the density. At higher energies, our approach provides quantitative results beyond the Luttinger-liquid theory. In particular, as the density increases, the interplay between dimensionality and interaction makes the dynamical structure factor manifest a pseudo-particle-hole continuum typical of fermionic systems. At the low-energy boundary of such a region and moderate densities, we find consistency, within statistical uncertainties, with predictions of a power-law structure by the recently developed nonlinear Luttinger-liquid theory. In the quasisolid regime, we observe a novel behavior at intermediate momenta, which can be described by new analytical relations that we derive for the hard-rods model.

cAMP effects in neuroendocrine tumors: The role of Epac and PKA in cell proliferation and adhesion.

cAMP effects have been initially attributed to protein kinase A (PKA) activation. Subsequently, two exchange proteins directly activated by cAMP (Epac1/2) have been identified as cAMP targets. Aim of this study was to investigate cAMP effects in pancreatic-NET (P-NET) and bronchial carcinoids and in corresponding cell lines (QGP-1 and H727) on cell proliferation and adhesion and to determine PKA and Epac role in mediating these effects. We found that cAMP increased cyclin D1 expression in P-NET and QGP-1 cells, whereas it had opposite effects on bronchial carcinoids and H727 cells and it promoted cell adhesion in QGP-1 and H727 cells. These effects are mimicked by Epac and PKA specific analogs, activating the small GTPase Rap1. In conclusion, we demonstrated that cAMP exerted divergent effects on proliferation and promoted cell adhesion of different neuroendocrine cell types, these effects being mediated by both Epac and PKA and involving the same effector GTPase Rap1.

Imaginary time density-density correlations for two-dimensional electron gases at high density.

We evaluate imaginary time density-density correlation functions for two-dimensional homogeneous electron gases of up to 42 particles in the continuum using the phaseless auxiliary field quantum Monte Carlo method. We use periodic boundary conditions and up to 300 plane waves as basis set elements. We show that such methodology, once equipped with suitable numerical stabilization techniques necessary to deal with exponentials, products, and inversions of large matrices, gives access to the calculation of imaginary time correlation functions for medium-sized systems. We discuss the numerical stabilization techniques and the computational complexity of the methodology and we present the limitations related to the size of the systems on a quantitative basis. We perform the inverse Laplace transform of the obtained density-density correlation functions, assessing the ability of the phaseless auxiliary field quantum Monte Carlo method to evaluate dynamical properties of medium-sized homogeneous fermion systems.

Filamin A in somatostatin and dopamine receptor regulation in pituitary and the role of cAMP/PKA dependent phosphorylation.

Molecular mechanisms underlying resistance of pituitary tumors to somatostatin (SS) and dopamine (DA) analogues treatment are not completely understood. Resistance has been associated with defective expression of functional somatostatin and dopamine receptors SSTR2, SSTR5, and DRD2, respectively. Recently, a role of cytoskeleton protein filamin A (FLNA) in DRD2 and SSTR receptors expression and signaling in PRL- and GH-secreting tumors, respectively, has been demonstrated, first revealing a link between FLNA expression and responsiveness of pituitary tumors to pharmacological therapy. No molecular events underlying the reduction of FLNA levels in resistant tumors have been so far identified. FLNA can be phosphorylated by PKA on Ser2152, with increased FLNA resistance to cleavage by calpain and conformational changes affecting FLNA regions involved in SSTR2 and DRD2 binding and signal transduction. In this respect, the effect of cAMP/PKA pathway in the regulation of FLNA stability and/or function by modulating its phosphorylation status could assume particular importance in pituitary, where cAMP cascade plays a crucial role in pituitary cell functions and tumorigenesis. This review will discuss the role of FLNA in the regulation of the main GPCRs target of pharmacological treatment of pituitary tumors, that is, SSTR2 and DRD2, focusing on the effects of cAMP/PKA-mediated FLNA phosphorylation on FLNA biological functions.

Filamin A (FLNA) plays an essential role in somatostatin receptor 2 (SST2) signaling and stabilization after agonist stimulation in human and rat somatotroph tumor cells.

Somatostatin receptor type 2 (SST2) is the main pharmacological target of medical therapy for GH-secreting pituitary tumors, but molecular mechanisms regulating its expression and signaling are largely unknown. The aim of this study was to investigate the role of cytoskeleton protein filamin A (FLNA) in SST2 expression and signaling in somatotroph tumor cells. We found a highly variable expression of FLNA in human GH-secreting tumors, without a correlation with SST2 levels. FLNA silencing in human tumoral cells did not affect SST2 expression and localization but abolished the SST2-induced reduction of cyclin D1 (-37% ± 15% in control cells, P < .05 vs basal) and caspase-3/7 activation (+63% ± 31% in control cells, P < .05 vs basal). Overexpression of a FLNA dominant-negative mutant that specifically prevents SST2-FLNA binding reduced SST2 expression after prolonged agonist exposure (-55% ± 5%, P < .01 vs untreated cells) in GH3 cells. Moreover, SST2-induced apoptotic effect (77% ± 54% increase of caspase activity, P < .05 vs basal) and SST2-mediated ERK1/2 inhibition (48% ± 17% reduction of ERK1/2 phosphorylation, P < .01 vs basal) were abrogated in cells overexpressing another FLNA mutant that prevents FLNA interaction with partner proteins but not with SST2, suggesting a scaffold function of FLNA in somatotrophs. In conclusion, these data demonstrate that FLNA is involved in SST2 stabilization and signaling in tumoral somatotrophs, playing both a structural and functional role.

Imaginary time correlations and the phaseless auxiliary field quantum Monte Carlo.

The phaseless Auxiliary Field Quantum Monte Carlo (AFQMC) method provides a well established approximation scheme for accurate calculations of ground state energies of many-fermions systems. Here we address the possibility of calculating imaginary time correlation functions with the phaseless AFQMC. We give a detailed description of the technique and test the quality of the results for static properties and imaginary time correlation functions against exact values for small systems.

Cyclic adenosine 3'-5'-monophosphate (cAMP) exerts proliferative and anti-proliferative effects in pituitary cells of different types by activating both cAMP-dependent protein kinase A (PKA) and exchange proteins directly activated by cAMP (Epac).

In the pituitary the activation of cyclic adenosine 3'-5'-monophosphate (cAMP) dependent pathways generates proliferative signals in somatotrophs, whereas in pituitary cells of other lineages its effect remains uncertain. Moreover, the specific role of the two main cAMP effectors, protein kinase A (PKA) and exchange proteins directly activated by cAMP (Epac), has not been defined. Aim of this study was to investigate the effect of cAMP on pituitary adenomatous cells proliferation and to identify PKA and Epac differential involvement. We found that cAMP increased DNA synthesis and cyclin D1 expression in somatotropinomas, whereas it reduced both parameters in prolactinomas and nonfunctioning adenomas, these effects being replicated in corresponding cell lines. Moreover, the divergent cAMP effects were mimicked by Epac and PKA analogs, which activated Rap1 and CREB, respectively. In conclusion, we demonstrated that cAMP exerted opposite effects on different pituitary cell types proliferation, these effects being mediated by both Epac and PKA.

Quantum dislocations: the fate of multiple vacancies in two-dimensional solid 4He.

Defects are believed to play a fundamental role in the supersolid state of (4)He. We have studied solid (4)He in two dimensions (2D) as a function of the number of vacancies n(v), up to 30, inserted in the initial configuration at ρ=0.0765 Å( - 2), close to the melting density, with the exact zero-temperature shadow path integral ground state method. The crystalline order is found to be stable also in the presence of many vacancies and we observe two completely different regimes. For small n(v), up to about 6, vacancies form a bound state and cause a decrease of the crystalline order. At larger n(v), the formation energy of an extra vacancy at fixed density decreases by one order of magnitude to about 0.6 K. It is no longer possible to recognize vacancies in the equilibrated state because they mainly transform into quantum dislocations and crystalline order is found almost independently of how many vacancies have been inserted in the initial configuration. The one-body density matrix in this latter regime shows a non-decaying large distance tail: dislocations, that in 2D are point defects, turn out to be mobile, their number is fluctuating, and they are able to induce exchanges of particles across the system mainly triggered by the dislocation cores. These results indicate that the notion of the incommensurate versus the commensurate state loses meaning for solid (4)He in 2D, because the number of lattice sites becomes ill defined when the system is not commensurate. Crystalline order is found to be stable also in 3D in the presence of up to 100 vacancies.

Slow growth of Empetrum nigrum in industrial barrens: combined effect of pollution and age of extant plants.

We studied the impact of industrial pollution on population demography (age structure), growth and reproduction of crowberry, Empetrum nigrum L. Crowberry growing in severely polluted sites near non-ferrous smelters (at Harjavalta, Monchegorsk and Nikel) was on average twice as old as in unpolluted habitats, as indicated by the number of annual rings at root collar. Shoot length decreased both with plant ageing and due to pollution impact, while neither the proportion of generative plants nor berry production was affected by pollution or plant age. Our results suggest that death of the extant individuals of E. nigrum near the non-ferrous smelters is to a large extent explained by age-related damage of the main stem accelerated by pollution. Since vegetative propagation, seed germination and seedling establishment are hampered by soil toxicity, E. nigrum populations near the smelters continue to decline with ageing in spite of the gradual decline of emissions.

Budburst phenology of white birch in industrially polluted areas.

Effects of environmental contamination on plant seasonal development have only rarely been properly documented. Monitoring of leaf growth in mountain birch, Betula pubescens subsp. czerepanovii, around a nickel-copper smelter at Monchegorsk hinted advanced budburst phenology in most polluted sites. However, under laboratory conditions budburst of birch twigs cut in late winter from trees naturally growing around three point polluters (nickel-copper smelter at Monchegorsk, aluminium factory at Kandalaksha, and iron pellet plant at Kostomuksha) showed no relationship with distance from the emission source. In a greenhouse experiment, budburst phenology of mountain birch seedlings grown in unpolluted soil did not depend on seedling origin (from heavily polluted vs. clean sites), whereas seedlings in metal-contaminated soil demonstrated delayed budburst. These results allow to attribute advanced budburst phenology of white birch in severely polluted sites to modified microclimate, rather than to pollution impact on plant physiology or genetics.

Postoperative radiotherapy after radical prostatectomy for prostate carcinoma: the experience of the Brescia Radium Institute.

PURPOSE: The purpose of this study was to evaluate the efficacy of postoperative radiotherapy in reducing the incidence of prostate carcinoma (PCa) recurrences after radical prostatectomy (RP), define the importance of the time interval between surgery and radiotherapy for prognosis and the toxicity of the treatment in comparison with radiotherapy or surgery alone. MATERIALS AND METHODS: We examined 97 patients who consecutively underwent postoperative radiotherapy after RP between 1980 and 2003. The treatment was considered "adjuvant" if was conducted less than 6 months after RP, if there was no macroscopic residual disease and if there was no progressive increase in serum prostate-specific antigen (PSA) and "salvage" if performed more than 6 months after RP, for the presence of macroscopic recurrence or with rising PSA. Radiotherapy was salvage in 56 patients and adjuvant in 41. Age range was 60-70 years in 80% of patients, and the Karnofsky index was over 80 in 78% of cases. Histology revealed extracapsular spread in 60% of patients. Preradiotherapy PSA was higher than 1 ng/ml in 36%. Radiotherapy was performed on the surgical bed only in 80%, and the total dose was 70 Gy in 62% of cases. RESULTS: Recurrence-free survival (RFS) at 5 years and 10 years was 53+/-8% and 32+/-14.2%, respectively, for the whole sample; 76+/-9% and 38+/-2.7% for patients treated with adjuvant radiotherapy and 36+/-10% and 28+/-10% for those treated with salvage radiotherapy (p<0.01). Moreover, the 5-year RFS was better in the group treated with adjuvant radiotherapy and PSA less than or equal to 1 ng/ml (p<0.05). Treatment toxicity was acceptable. CONCLUSIONS: Postoperative radiotherapy improves RFS and reduces the risk of local recurrence. The best results are obtained with early postoperative treatment ("adjuvant"); adjuvant radiotherapy of high-risk forms yields better results if performed with PSA less than or equal to 1 ng/ml.