313 research outputs found

    Ribosomal stress activates eEF2K-eEF2 pathway causing translation elongation inhibition and recruitment of Terminal Oligopyrimidine (TOP) mRNAs on polysomes

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    The synthesis of adequate amounts of ribosomes is an essential task for the cell. It is therefore not surprising that regulatory circuits exist to organize the synthesis of ribosomal components. It has been shown that defect in ribosome biogenesis (ribosomal stress) induces apoptosis or cell cycle arrest through activation of the tumor suppressor p53. This mechanism is thought to be implicated in the pathophysiology of a group of genetic diseases such as Diamond Blackfan Anemia which are called ribosomopathies. We have identified an additional response to ribosomal stress that includes the activation of eukaryotic translation elongation factor 2 kinase with a consequent inhibition of translation elongation. This leads to a translational reprogramming in the cell that involves the structurally defined group of messengers called terminal oligopyrimidine (TOP) mRNAs which encode ribosomal proteins and translation factors. In fact, while general protein synthesis is decreased by the impairment of elongation, TOP mRNAs are recruited on polysomes causing a relative increase in the synthesis of TOP mRNA-encoded proteins compared to other proteins. Therefore, in response to ribosomal stress, there is a change in the translation pattern of the cell which may help restore a sufficient level of ribosomes

    The inhibition of FGF receptor 1 activity mediates sorafenib-induced antiproliferative effects in human mesothelioma tumor-initiating cells

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    Tumor-initiating cells (TICs), the subset of cells within tumors endowed with stem-like features, being highly resistant to conventional cytotoxic drugs, are the major cause of tumor relapse. The identification of molecules able to target TICs remains a significant challenge in cancer therapy. Using TIC-enriched cultures (MM1, MM3 and MM4), from 3 human malignant pleural mesotheliomas (MPM), we tested the effects of sorafenib on cell survival and the intracellular mechanisms involved. Sorafenib inhibited cell-cycle progression in all the TIC cultures, but only in MM3 and MM4 cells this effect was associated with induction of apoptosis via the down-regulation of Mcl-1. Although sorafenib inhibits the activity of several tyrosine kinases, its effects are mainly ascribed to Raf inhibition. To investigate the mechanisms of sorafenib-mediated antiproliferative activity, TICs were treated with EGF or bFGF causing, in MM3 and MM4 cells, MEK, ERK1/2, Akt and STAT3 phosphorylation. These effects were significantly reduced by sorafenib in bFGF-treated cells, while a slight inhibition occurred after EGF stimulation, suggesting that sorafenib effects are mainly due to FGFR inhibition. Indeed, FGFR1 phosphorylation was inhibited by sorafenib. A different picture was observed in MM1 cells, which, releasing high levels of bFGF, showed an autocrine activation of FGFR1 and a constitutive phosphorylation/activation of MEK-ERK1/2. A powerful inhibitory response to sorafenib was observed in these cells, indirectly confirming the central role of sorafenib as FGFR inhibitor. These results suggest that bFGF signaling may impact antiproliferative response to sorafenib of MPM TICs, which is mainly mediated by a direct FGFR targeting

    AMP-activated protein kinase - not just an energy sensor

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    Orthologues of AMP-activated protein kinase (AMPK) occur in essentially all eukaryotes as heterotrimeric complexes comprising catalytic α subunits and regulatory β and γ subunits. The canonical role of AMPK is as an energy sensor, monitoring levels of the nucleotides AMP, ADP, and ATP that bind competitively to the γ subunit. Once activated, AMPK acts to restore energy homeostasis by switching on alternate ATP-generating catabolic pathways while switching off ATP-consuming anabolic pathways. However, its ancestral role in unicellular eukaryotes may have been in sensing of glucose rather than energy. In this article, we discuss a few interesting recent developments in the AMPK field. Firstly, we review recent findings on the canonical pathway by which AMPK is regulated by adenine nucleotides. Secondly, AMPK is now known to be activated in mammalian cells by glucose starvation by a mechanism that occurs in the absence of changes in adenine nucleotides, involving the formation of complexes with Axin and LKB1 on the surface of the lysosome. Thirdly, in addition to containing the nucleotide-binding sites on the γ subunits, AMPK heterotrimers contain a site for binding of allosteric activators termed the allosteric drug and metabolite (ADaM) site. A large number of synthetic activators, some of which show promise as hypoglycaemic agents in pre-clinical studies, have now been shown to bind there. Fourthly, some kinase inhibitors paradoxically activate AMPK, including one (SU6656) that binds in the catalytic site. Finally, although downstream targets originally identified for AMPK were mainly concerned with metabolism, recently identified targets have roles in such diverse areas as mitochondrial fission, integrity of epithelial cell layers, and angiogenesis

    FISH testing of HER2 IHC 1+ early breast cancer with unfavorable prognostic factors

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    FISH testing of HER2 IHC 1+ early breast cancer with unfavorable prognostic factors Background HER2-positive tumors are associated with a poor prognosis and a shortened disease-free and overall survival as well as with other unfavorable prognostic tumor characteristics (high histological grade, high proliferative index, negative or low estrogen receptor expression, etc.). HER2-positive tumors are also responsive to treatment with trastuzumab in reducing the risk of recurrence and improving survival. The aim of this study is to assess the incidence of HER2 gene amplification in selected tumors with adverse prognostic features which scored 1+ by immunohistochemistry (IHC). Methods 75 women with infiltrating ductal carcinoma (IDC) and infiltrating lobular carcinoma (ILC) scoring 1+ by IHC were included. Forty-eight invasive breast carcinoma samples were selected according to unfavorable prognostic tumor characteristics and tested by FISH. HER2 amplification was evaluated using Vysis HER2/Cep17 probe (Path Vysion HER2 DNA Probe Kit®, Abbott Molecular, IL); ratio–based amplification was considered present when the HER2/Cep17 ratio was 2 or more and copy number-based amplification was considered present when the mean HER2 copy number was more than 6, in agreement with the ASCO/CAP/SIAPEC guidelines. Results In 2013, 331 patients with invasive breast tumors were tested by IHC; 75 cases (23%) were scored 1+ of which 62 cases (19%) of IDC and 13 cases (4%) of ILC. Forty-eight invasive breast carcinoma samples (64%) were selected according to one or more unfavorable prognostic tumor characteristics; 22 out of 48 tumors (46%) showed high histological grade (G3); 27 cases (56%) had high proliferative index (Ki-67≥30%); 32 tumor samples (67%) were node-positive; and 29 cases (60%) showed vascular invasion. FISH was performed on 31 of the 1+ patients with adverse tumor characteristics and 7 IDC out of 48 (14.6%) showed HER2 amplification. Conclusions Our preliminary retrospective data suggest that 7 patients out of 48 (14.6%) scoring 1+ by IHC show HER2 amplification, in agreement with the most recently published literature data. In order to not deny the benefit deriving from trastuzumab administration, in breast cancer patients showing IHC 1+, it is advisable to test HER2 gene amplification by FISH. Bibliografia Goldhirsch A, Gelber RD, Piccart-Gebhart MJ, de Azambuja E, Procter M, Suter TM, Jackisch C, Cameron D, Weber HA, Heinzmann D, Dal Lago L, McFadden E, Dowsett M, Untch M, Gianni L, Bell R, Köhne CH, Vindevoghel A, Andersson M, Brunt AM, Otero-Reyes D, Song S, Smith I, Leyland-Jones B, Baselga J; Herceptin Adjuvant (HERA) Trial Study Team. 2 years versus 1 year of adjuvant trastuzumab for HER2-positive breast cancer (HERA): an open-label, randomised controlled trial. Lancet. 2013 Sep 21;382(9897):1021-8. Iorfida M, Dellapasqua S, Bagnardi V, Cardillo A, Rotmensz N, Mastropasqua MG, Bottiglieri L, Goldhirsch A, Viale G, Colleoni M. HER2-negative (1+) breast cancer with unfavorable prognostic features: to FISH or not to FISH? Ann Oncol. 2012 May;23(5):1371-2. Romond EH, Perez EA, Bryant J, Suman VJ, Geyer CE Jr, Davidson NE, Tan-Chiu E, Martino S, Paik S, Kaufman PA, Swain SM, Pisansky TM, Fehrenbacher L, Kutteh LA, Vogel VG, Visscher DW, Yothers G, Jenkins RB, Brown AM, Dakhil SR, Mamounas EP, Lingle WL, Klein PM, Ingle JN, Wolmark N. Trastuzumab plus adjuvant chemotherapy for operable HER2-positive breast cancer. N Engl J Med. 2005 Oct 20;353(16):1673-84

    Efficacy and tolerability of Brevilin-A, a natural JAK inhibitor, in pediatric alopecia areata: a case series

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    Alopecia areata represents an autoimmune disease that specifically damages growing hair follicles on the scalp and/or around the body. Janus kinase inhibitors have been identified as an effective therapy in adult patients and topical formulations, such as Brevilin-A, might represent a well-tolerated treatment for mild-moderate disease in children and adolescents. the mechanism of action of Brevilin-A, a sesquiterpene lactone isolated from centipeda minima, could consist in blocking STAT3 and STAT1 signaling as well as the JAKs activity by inhibiting the JAKs tyrosine kinase domain JH1. we report our cases of successful application of Brevilin-A in pediatric patients, suggesting this treatment as a safe and effective therapeutic option also for recalcitrant alopecia areata in pediatric population

    COVID‐19, Vaccines, and Thrombotic Events: A Narrative Review

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    The coronavirus disease 2019 (COVID‐19), a deadly pandemic that has affected millions of people worldwide, is associated with cardiovascular complications, including venous and arterial thromboembolic events. Viral spike proteins, in fact, may promote the release of prothrombotic and inflammatory mediators. Vaccines, coding for the spike protein, are the primary means for preventing COVID‐19. However, some unexpected thrombotic events at unusual sites, most frequently located in the cerebral venous sinus but also splanchnic, with associated thrombocytopenia, have emerged in subjects who received adenovirus‐based vaccines, especially in fertile women. This clinical entity was soon recognized as a new syndrome, named vaccine-induced immune thrombotic thrombocytopenia, probably caused by cross‐reacting anti‐platelet factor‐4 antibodies activating platelets. For this reason, the regulatory agencies of various countries restricted the use of adenovirus‐based vaccines to some age groups. The prevailing opinion of most experts, however, is that the risk of developing COVID‐19, including thrombotic complications, clearly outweighs this potential risk. This point‐of‐view aims at providing a narrative review of epidemiological issues, clinical data, and pathogenetic hypotheses of thrombosis linked to both COVID‐19 and its vaccines, helping medical practitioners to offer up‐to‐date and evidence‐based counseling to their often‐alarmed patients with acute or chronic cardiovascular thrombotic events

    ANMCO POSITION PAPER: Timing of coronary angiography in non-ST-segment elevation acute coronary syndromes

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    The European Society of Cardiology guidelines on non-ST-elevation acute coronary syndromes suggest different temporal strategies for the angiographic study depending on the risk profile. The scientific evidence underlying the guideline recommendations and the critical issues currently existing in Italy, that often do not allow either an extended strategy of revascularization within 24 h or the application of the principle of the same day transfer from a spoke to a hub centre, are analysed. The position paper focuses, in particular, on the subgroup of patients with a defined diagnosis of non-ST-elevation myocardial infarction by proposing a timing of coronary angiography/revascularization that takes into account the available scientific evidence and the organizational possibilities of a considerable part of national cardiology services

    Tildrakizumab in moderate-to-severe plaque psoriasis: A multicenter, retrospective, real-life study

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    New biologic agents targeting interleukin (IL)23/T-helper17 axis, such as tildrakizumab, have been developed for the treatment of plaque psoriasis. To analyze the efficacy and safety of tildrakizumab in a real life setting of patients affected by moderate-to-severe psoriasis over a 28-week treatment period. A multicentric retrospective study was conducted in patients who initiated tildrakizumab between February 2020 and March 2021. Psoriasis Area and Severity Index-PASI was measured at baseline and after 4, 16 and 28 weeks. The percentage change in PASI value from baseline to the considered time-points, proportion of patients with absolute PASI <3 at week 28 and the percentages of achieving a PASI75 or PASI90 response were assessed. Data about potential safety issues and adverse events (AEs) were collected. Statistical analysis were performed for establish clinical efficacy and for variables predicting clinical response. Fifty nine patients with psoriasis were included. Overall mean PASI percentage reduction was of 88% from baseline to week 28 and 47 out of 59 patients (79.7%) at week 28 had an absolute PASI <3. PASI75 and PASI90 responses at week 28 were achieved by 48 (81.40%) patients and 38 (64.4.0%) patients, respectively. No substantial associations between gender, body mass index - BMI, PASI at baseline and prior exposition to biological therapies and the efficacy endpoints were retrieved. No serious safety issues or discontinuations related to adverse events were reported. In our real-life study, tildrakizumab showed high efficacy and a favorable safety profile, regardless of patient- and disease-related factors

    ANMCO position paper on the management of hypercholesterolaemia in patients with acute coronary syndrome

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    Patients suffering from acute coronary syndrome (ACS) present a high risk of recurrence and new adverse cardiovascular events after hospital discharge. Elevated plasma LDL-cholesterol (LDL-C) levels have been shown to be a causal factor for the development of coronary heart disease, and robust clinical evidence has documented that LDL-C levels decrease linearly correlates with a reduction in cardiovascular events. Recent studies have also demonstrated the safety and efficacy of an early and significant reduction in LDL-C levels in patients with ACS. In this position paper, Italian Association of Hospital Cardiologists proposes a decision algorithm on early adoption of lipid-lowering strategies at hospital discharge and short-term follow-up of patients with ACS, in the light of the multiple evidence generated in recent years on the treatment of hypercholesterolaemia and the available therapeutic options, considering current reimbursement criteria

    Circular dichroism measurement of single metal nanoparticles using photothermal imaging

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    Circular dichroism (CD) spectroscopy is a powerful optical technique for the study of chiral materials and molecules. It gives access to an enantioselective signal based on the differential absorption of right and left circularly polarized light, usually obtained through polarization analysis of the light transmitted through a sample of interest. CD is routinely used to determine the secondary structure of proteins and their conformational state. However, CD signals are weak, limiting the use of this powerful technique to ensembles of many molecules. Here, we experimentally realize the concept of photothermal circular dichroism, a technique that combines the enantioselective signal from circular dichroism with the high sensitivity of photothermal microscopy, achieving a superior signal-to-noise ratio to detect chiral nano-objects. As a proof of principle, we studied the chiral response of single plasmonic nanostructures with CD in the visible range, demonstrating a signal-to-noise ratio better than 40 with only 30 ms integration time for these nanostructures. The high signal-to-noise ratio allows us to quantify the CD signal for individual nanoparticles. We show that we can distinguish relative absorption differences for right circularly and left circularly polarized light as small as gmin = 4 × 10–3 for a 30 ms integration time with our current experimental settings. The enhanced sensitivity of our technique extends CD studies to individual nano-objects and opens CD spectroscopy to numbers of molecules much lower than those in conventional experiments.Biological and Soft Matter Physic
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