38 research outputs found
p63 is an alternative p53 repressor in melanoma that confers chemoresistance and a poor prognosis.
The role of apoptosis in melanoma pathogenesis and chemoresistance is poorly characterized. Mutations in TP53 occur infrequently, yet the TP53 apoptotic pathway is often abrogated. This may result from alterations in TP53 family members, including the TP53 homologue TP63. Here we demonstrate that TP63 has an antiapoptotic role in melanoma and is responsible for mediating chemoresistance. Although p63 was not expressed in primary melanocytes, up-regulation of p63 mRNA and protein was observed in melanoma cell lines and clinical samples, providing the first evidence of significant p63 expression in this lineage. Upon genotoxic stress, endogenous p63 isoforms were stabilized in both nuclear and mitochondrial subcellular compartments. Our data provide evidence of a physiological interaction between p63 with p53 whereby translocation of p63 to the mitochondria occurred through a codependent process with p53, whereas accumulation of p53 in the nucleus was prevented by p63. Using RNA interference technology, both isoforms of p63 (TA and ÎNp63) were demonstrated to confer chemoresistance, revealing a novel oncogenic role for p63 in melanoma cells. Furthermore, expression of p63 in both primary and metastatic melanoma clinical samples significantly correlated with melanoma-specific deaths in these patients. Ultimately, these observations provide a possible explanation for abrogation of the p53-mediated apoptotic pathway in melanoma, implicating novel approaches aimed at sensitizing melanoma to therapeutic agents
VEGF165-induced vascular permeability requires NRP1 for ABL-mediated SRC family kinase activation.
The vascular endothelial growth factor (VEGF) isoform VEGF165 stimulates vascular growth and hyperpermeability. Whereas blood vessel growth is essential to sustain organ health, chronic hyperpermeability causes damaging tissue edema. By combining in vivo and tissue culture models, we show here that VEGF165-induced vascular leakage requires both VEGFR2 and NRP1, including the VEGF164-binding site of NRP1 and the NRP1 cytoplasmic domain (NCD), but not the known NCD interactor GIPC1. In the VEGF165-bound receptor complex, the NCD promotes ABL kinase activation, which in turn is required to activate VEGFR2-recruited SRC family kinases (SFKs). These results elucidate the receptor complex and signaling hierarchy of downstream kinases that transduce the permeability response to VEGF165. In a mouse model with choroidal neovascularisation akin to age-related macular degeneration, NCD loss attenuated vessel leakage without affecting neovascularisation. These findings raise the possibility that targeting NRP1 or its NCD interactors may be a useful therapeutic strategy in neovascular disease to reduce VEGF165-induced edema without compromising vessel growth
Acute Delta Hepatitis in Italy spanning three decades (1991â2019): Evidence for the effectiveness of the hepatitis B vaccination campaign
Updated incidence data of acute Delta virus hepatitis (HDV) are lacking worldwide. Our aim was to evaluate incidence of and risk factors for acute HDV in Italy after the introduction of the compulsory vaccination against hepatitis B virus (HBV) in 1991. Data were obtained from the National Surveillance System of acute viral hepatitis (SEIEVA). Independent predictors of HDV were assessed by logistic-regression analysis. The incidence of acute HDV per 1-million population declined from 3.2 cases in 1987 to 0.04 in 2019, parallel to that of acute HBV per 100,000 from 10.0 to 0.39 cases during the same period. The median age of cases increased from 27 years in the decade 1991-1999 to 44 years in the decade 2010-2019 (p < .001). Over the same period, the male/female ratio decreased from 3.8 to 2.1, the proportion of coinfections increased from 55% to 75% (p = .003) and that of HBsAg positive acute hepatitis tested for by IgM anti-HDV linearly decreased from 50.1% to 34.1% (p < .001). People born abroad accounted for 24.6% of cases in 2004-2010 and 32.1% in 2011-2019. In the period 2010-2019, risky sexual behaviour (O.R. 4.2; 95%CI: 1.4-12.8) was the sole independent predictor of acute HDV; conversely intravenous drug use was no longer associated (O.R. 1.25; 95%CI: 0.15-10.22) with this. In conclusion, HBV vaccination was an effective measure to control acute HDV. Intravenous drug use is no longer an efficient mode of HDV spread. Testing for IgM-anti HDV is a grey area requiring alert. Acute HDV in foreigners should be monitored in the years to come
26th Annual Computational Neuroscience Meeting (CNS*2017): Part 3 - Meeting Abstracts - Antwerp, Belgium. 15â20 July 2017
This work was produced as part of the activities of FAPESP Research,\ud
Disseminations and Innovation Center for Neuromathematics (grant\ud
2013/07699-0, S. Paulo Research Foundation). NLK is supported by a\ud
FAPESP postdoctoral fellowship (grant 2016/03855-5). ACR is partially\ud
supported by a CNPq fellowship (grant 306251/2014-0)
Ruolo di iASPP nella regolazione del Mismatch repair in melanoma
Dottorato di Ricerca in Farmacologia e Biochimica della Morte Cellulare, Ciclo XXII, a.a. 2009-2010Cutaneous melanoma is an aggressive malignancy accounting for 4% of skin cancers but 80% of all skin-cancer related deaths. Its incidence is rapidly rising and advanced disease is notoriously treatment-resistant. The role of apoptosis in melanoma pathogenesis and chemoresistance is poorly characterized. Mutations in p53 occur infrequently and are not critical for tumour development. This may alternatively result from p53 upstream or downstream pathway defects or from alterations of p53 family co-activators, including the ASPP family members (Apoptosis Stimulating Proteins of p53).
iASPP is the inhibitory member of the ASPP family. By binding p53, iASPP is believed to inhibit apoptosis in cancer, resulting in its oncogenic role. Recently it has been found highly expressed in several types of cancer, such as endometrial and hepatocellular carcinoma, acute leukemia and breast cancer. iASPP upregulation in some cases occurs with a concomitant downregulation of ASPP expression, the pro-apoptotic family member, thus providing a further option for targeting the p53 family in the treatment of cancers. So far, iASPP expression and its role in skin cancer is not yet been explored.
Recently great attention has been given to DNA repair processes in melanoma, particularly to Mismatch Repair (MMR). This is a DNA damage repair mechanism, correcting bases mismatches due to replication errors or exogenous agentsâ activity, whose defects have been demonstrated leading to genomic instability (microsatellite instability, MSI) frequently linked with cancer. MSI and altered expression of MMR factors such as MSH2 and MLH1 (both at mRNA and protein levels) has often been observed in primary and metastatic melanoma, compared to normal melanocytes and nevi.
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Aim of this study is to investigate the role of iASPP in melanoma and particularly its involvement in DNA repair and apoptosis. In this work we used RT-PCR and western blot techniques to demonstrate that both MMR factors and iASPP were expressed at higher levels in several melanoma cell lines, mainly metastatic, compared to primary melanocytes extracted from human skin. We also observed a post-translational modification in the MSH2 protein (which is due at least to an ubiquitination) upon increased iASPP expression in three different melanoma cell lines, independently of p53 status. This results in an increase of DNA repair activity measured by MutS(MSH2/MSH6 complex) binding to a DNA bases mismatch. To confirm these results, we used a set of shRNAs targeting iASPP gene in metastatic melanoma cell line WM1158 and we found that the reduction of iASPP leads to a lower MSH2 protein expression, without affecting MLH1, and to a 50% reduction of MutS activity. Immunoprecipitation experiments showed that iASPP directly binds endogenous MSH2 and MLH1 in melanoma cells and this interaction was confirmed by immunostaining where iASPP partially co-localized with MMR factors in the nucleus of melanoma cells. Moreover, iASPP silencing and its consequent reduction in expression and activity of MMR factors, is able to sensitize melanoma cells to apoptosis induced by chemotherapeutic agent cisplatin.
Taken together these results confirm the antiapoptotic role of iASPP and suggest a novel role of iASPP in melanoma, such as a modulator of MMR that may help in the future to explain further its oncogenic role in cancer. This study is also the first report available about iASPP expression in melanoma, highlighting the importance of investigating further this important target gene in such a chemoresistant disease. Future studies will be necessary to further elucidate the mechanism by which iASPP interferes with the MMR system and how it affects apoptosis and cell cycle progression in melanoma disease.UniversitĂ della Calabri
NEW FIBER COMPOSITE MATERIALS FOR CULTURAL HERITAGE CONSERVATION
New fiber composite materials are presented in this work. They have been obtained by treating the surface of the fibers with a silane reactant used in the compounding stage to connect vegetables and mineral fibers to the other chemical components of the final composite materials. The silane reactant links on the surface of the fiber forming strong covalent bonds through the Si atoms. The other end moiety of the silane reactant carries an ammine group which is able to bind to epoxides in a copolymerization process. In such a way the fiber themselves becomes part of polymer networks which have much better mechanical properties with respect to the composite materials obtained by simply dispersing the fibres into polymer matrices. The observed physical and mechanical proprieties of these fiber composites candidates them to have future interesting applications in the field of conservation of cultural heritage
Endocrine Alterations Are the Main Determinants of Cardiac Remodelling in Restrictive Anorexia Nervosa
Objective. Anorexia nervosa is a condition of reduced hemodynamic load, characterized by varying degrees of cardiac remodelling, only in part related to reduced body mass; the mechanism for such variability, as well as its clinical significance, remains unknown. Aim of the study was to assess the possible influence of a great number of clinical, biochemical, and endocrine factors on cardiovascular parameters in restrictive anorexia nervosa. Method. Twenty-five female patients hospitalized for restrictive anorexia nervosa underwent extensive cardiovascular, clinical, and biochemical evaluation. Results. Height-adjusted and cardiac workload-matched left ventricular mass was significantly related to several endocrine parameters, blood pressure, and vasoreactivity. On multivariate analysis, IGF/GH ratio and systolic blood pressure were the only independent predictors of height-adjusted ventricular mass (adj-R(2) = 0.585; P = 0.001); when matching for cardiac workload, left ventricular mass was independently predicted only by GH and FT3 levels. All effects were independent of patient's weight and BMI. Conclusions. Indices of endocrine impairment seem to be the most relevant determinants of left ventricular hypotrophy in anorectic patients, apparently independent of reduced hemodynamic load and BMI. In particular, IGF/GH ratio and FT3 seem to particularly affect left ventricular mass in this population
Correction: The Calmodulin-Binding, Short Linear Motif, NSCaTE Is Conserved in L-Type Channel Ancestors of Vertebrate Cav1.2 and Cav1.3 Channels.
NSCaTE is a short linear motif of (xWxxx(I or L)xxxx), composed of residues with a high helix-forming propensity within a mostly disordered N-terminus that is conserved in L-type calcium channels from protostome invertebrates to humans. NSCaTE is an optional, lower affinity and calcium-sensitive binding site for calmodulin (CaM) which competes for CaM binding with a more ancient, C-terminal IQ domain on L-type channels. CaM bound to N- and C- terminal tails serve as dual detectors to changing intracellular Ca(2+) concentrations, promoting calcium-dependent inactivation of L-type calcium channels. NSCaTE is absent in some arthropod species, and is also lacking in vertebrate L-type isoforms, Cav1.1 and Cav1.4 channels. The pervasiveness of a methionine just downstream from NSCaTE suggests that L-type channels could generate alternative N-termini lacking NSCaTE through the choice of translational start sites. Long N-terminus with an NSCaTE motif in L-type calcium channel homolog LCav1 from pond snail Lymnaea stagnalis has a faster calcium-dependent inactivation than a shortened N-termini lacking NSCaTE. NSCaTE effects are present in low concentrations of internal buffer (0.5 mM EGTA), but disappears in high buffer conditions (10 mM EGTA). Snail and mammalian NSCaTE have an alpha-helical propensity upon binding Ca(2+)-CaM and can saturate both CaM N-terminal and C-terminal domains in the absence of a competing IQ motif. NSCaTE evolved in ancestors of the first animals with internal organs for promoting a more rapid, calcium-sensitive inactivation of L-type channels