1,720,994 research outputs found
The pan-HDAC inhibitor AR42 downregulates CD44 expression, a new circulating prognostic factor for multiple myeloma
No full textIl Mieloma Multiplo (MM) e’ un tumore ematologico che colpisce le plasma cellule (PCs) nel midollo osseo. Lo scambio di informazioni tra le MM-PCs e il microambiente nel midollo osseo, tra le quali quelle dovute alle interazioni cellula-cellula, il rilascio di fattori pro-sopravvivenza e vescicole extracellulari (EV), promuove la sopravvivenza tumorale e la resistenza ai farmaci. All’inizio la mia ricerca si e’ focalizzata sulla caratterizzazione del contenuto proteico delle EVs rilasciate dalle cellule di MM. Tra tutte le protein identificate, la glicoproteina CD44 e’ una delle piu’ abbondanti ed e’ stata gia’ associata, sia in vitro che in vivo, con la resistenza del mieloma multiplo al dexamethasone e alla lenalidomide. L’analisi di 200 campioni di siero estratti da pazienti affetti da mieloma multiplo mostra che il CD44 circolante e trasportato dalle MM-EVs correla con ISS stage e i livelli di β2microglobulina e costituisce un potenziale fattore prognostico, fornendo in questo modo il razionale per successive investigazioni di nuovi biomarker associati con lo stato della malattia. Nonostante le molte opzioni terapeutiche possibili, il MM e’ inevitabilmente associato con la resistenza e la scarsa efficacia farmacologica. Gli inibitori delle istoni-deacetilasi (HDACi) costituiscono una nuova classe di chemioterapici in valutazione in trials clinici per il trattamento di pazienti affetti da mieloma multiplo. Anche se gli studi preclinici sugli HDACi hanno dimostrato la loro attivita’ anti-mieloma, nella clinica i trattamenti con gli HDACi sono purtroppo limitati a causa della loro bassa tollerabilita’. Noi crediamo che gli HDACi possano costituire un valido supporto se impiegati in combinazione con lo standard terapeutico per il mieloma multiplo. In questa tesi mostro che un nuovo panHDACi, l’AR42, abbassa l’espressione del CD44. Questa down-regolazione e’ in parte mediata dal miR-9-5p, il quale sopprime l’espressione dell’insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3), uno stabizzatore dell’ RNA messaggero del CD44. Abbiamo dimostrato che l’AR42 aumenta l’attivita’ della lenalidomide sia in cellule primarie di MM isolate da pazienti refrattari al trattamento con la lenalidomide sia in modello murino di mieloma multiplo. In conclusione, i nostri dati suggeriscono una nuova potenziale combinazione terapeutica che modula l’espressione del CD44 e che potrebbe aiutare ad attenuare la resistenza alla lenalidomide nei pazienti affetti da mieloma.Multiple myeloma (MM) is a hematological malignancy of plasma cells (PCs) in the bone marrow. The interplay between MM-PCs and bone marrow microenvironment, including cell-cell contacts and release of pro-survival factors and extracellular vescicles (EV), promotes cancer cell survival and drug resistance. At first my research was focused on the characterization of the proteomic content of EVs secreted by MM cell lines. Among them, the glycoprotein CD44 is one of the most abundant proteins and has been already associated, both in vivo and in vitro, with lenalidomide and dexamethasone resistance in multiple myeloma. The analysis of serum samples from a cohort of 200 MM patients shows that circulating CD44 carried by MM-EVs correlates with ISS stage and β2microglobulin and constitutes a potential prognostic factor, thus providing the rationale to further explore novel molecular players associated with MM disease. Despite multiple treatment options, MM is inevitably associated with drug resistance and poor outcomes. Histone deacetylase inhibitors (HDACi’s) are promising novel chemotherapeutics under evaluation in clinical trials for the treatment of MM patients. Although in preclinical studies HDACi’s have proven anti-myeloma activity, in the clinics single-agent HDACi treatments have been limited due to low tolerability. We believe that HDACi could constitute a valid support if used in combination with the MM state of care. In this thesis I show that a novel pan-HDACi AR42 downregulates CD44. Moreover, the CD44 downregulation is in part mediated by miR-9-5p, targeting insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3), which directly binds to CD44 mRNA and increases its stability. Importantly, we demonstrate that AR42 enhances anti-myeloma activity of lenalidomide in primary MM cells isolated from lenalidomide resistant patients and in MM mouse model. In conclusion, our observations suggest a potential novel combinatorial therapeutic approach modulating CD44 expression, which may help overcome lenalidomide resistance in myeloma patients
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Arecoline tripeptide inhibitors of proteasome
No full textThe 26S proteasome is a multicatalytic protease complex that plays an essential role in
intracellular protein degradation. We have synthesized and tested a series of arecoline peptide
derivatives where the peptide portion derives from a screening of tripeptide sequences, and
the arecoline moiety has been considered as a potential substrate for catalytic threonine.
Derivatives 17-19 are the best compounds of the series, showing chymotryptic-like (â5)
inhibition (IC50 = 1 íM) and favorable pharmacokinetic properties
Phosphinic platinum complexes with 8-thiotheophylline derivatives: Synthesis, characterization, and antiproliferative activity
No full textThe platinum mixed-phosphine complexes (SP-4,2)-[PtCl(8-MTT)(PPh3)(PTA)] (2) and cis-[Pt(8-MTT)(2)(PPh3)(PTA)] (3) (MTTH2 = 8-(methylthio)theophylline, PTA = 1,3,5-triaza-7-phosphaadamantane) have been prepared from the precursor cis-[PtCl2(PPh3)(PTA)] (1), which has been fully characterized by X-ray diffraction determination. Antiproliferative activity tests indicated that the presence of one lipophilic PPh3 and one hydrophilic PTA makes 1-3 more active than the analogues bearing two PPh3 or two PTA. The reactivity of cis-[PtCl2(PPh3)(2)], cis-[PtCl2(PTA)(2)], and cis-[PtCl2(PPh3)(PTA)] with the bis(thiopurines) bis(S-8-thiotheophylline)methane (MBTTH2), 1,2-bis(S-8-thiotheophylline)ethane (EBTTH2), and 1,3-bis(S-8-thiotheophylline)propane (PBTTH2) has also been investigated. New binuclear complexes have been prepared and identified by spectroscopic techniques and their antiproliferative activities on T2 and SKOV3 cell lines evaluated
The Toll-like receptor ligand MALP-2 stimulates dendritic cell maturation and modulates proteasome composition and activity
No full textA 2-kDa synthetic derivative of the macrophage-activating lipopeptide (MALP-2) from Mycoplasma fermentans is a potent inducer of monocytes/macrophages and improves the immunogenicity of antigens co-administered by systemic and mucosal routes. Dendritic cells (DC) are the most potent antigen-presenting cells, which are able to prime naive T cells in vivo. To elucidate the underlying mechanisms of MALP-2 adjuvanticity, we analyzed its activity on bone marrow-derived murine DC. In vitro stimulation of immature murine DC with MALP-2 resulted in the induction of maturation with up-regulated expression of MHC class II, costimulatory (CD80, CD86) and adhesion (CD40, CD54) molecules. MALP-2 also enhances the secretion of cytokines (IL-1alpha, IL-6 and IL-12), and increases DC stimulatory activity on naive and antigen-specific T cells. Further studies demonstrated that MALP-2 treatment of DC results in a dose-dependent shift from the protein pattern of proteasomes to immunoproteasomes (up-regulation of LMP2, LMP7 and MECL1), which correlates with an increased proteolytic activity. Thus, the adjuvanticity of MALP-2 can be mediated, at least in part, by the stimulation of DC maturation, which in turn leads to an improved antigen presentation. Therefore, MALP-2 is a promising molecule for the development of immune therapeutic or prophylactic interventions
High Porosity Bioceramic is a Favourable Environment for the Adhesion and Proliferation of Human Mesenchymal Stem Cells.
No full textIn the orthopaedic perspective, tissue engineering is focused on the development of innovative materials, whose action consists in recruiting bone progenitor cells and in stimulating their proliferation. In this study, we investigated the effects of hydroxylapatite (HA) biomaterials, which differ in composition and form, on human mesenchymal stem cells (hMSCs). Doubling time variability among hMSC samples and their passages was investigated in “in vitro” cultures. Flow cytometric analysis was performed to characterize cell population towards specific mesenchymal stem cell surface markers. hMSCs viability, biocompatibility, adhesion and proliferation on different biomaterials were also investigated. Furthermore, hMSCs morphology was evaluated during their growth on biomaterials by scanning electron microscopy (SEM) analysis. hMSCs cytoskeleton was investigated by immunofluorescence assay to evaluate the effects of biomaterials on cell structure and organization
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Naturally occurring truncated proteins: decreased protein secretion and increased activity result in asymptomatic coagulation factor deficiency
No full textFactor VII (FVII), IX (FIX), X and protein C (PC), having distinct protein properties and specificities, belong to the coagulation serine protease family that evolved from a common ancestor. In spite of high homology at the gene and protein levels, they show remarkable differences in the carboxyl-terminal region. The C-terminus of FIX and PC has been shown to be essential for secretion but not function. To address this issue in FVII we took advantage from the identification of the homozygous R402Stop nonsense mutation in two asymptomatic FVII deficient patients. FVII protein and coagulant activity levels in patients’ plasma were 0,8% and 5% of normal, respectively, thus suggesting the presence of truncated molecules (FVII-R402Stop, natural stop codon at 407 position), poorly secreted but with improved procoagulant activity. Functional FXa and Thrombin generation assays in plasma confirmed these observations. To investigate these features, we expressed the naturally truncated FVII-402Stop and the FVII variants 403-406Stop. Similarly to the natural mutant, the rFVII-403Stop and rFVII-402Stop variants were poorly secreted (~1%). We found an inverse relationship between secreted protein levels in media and the extent of the deletion for the rFVII-406Stop (50-60% of WT), rFVII-405Stop (15-20%) and rFVII-404Stop (9-12%). FXa generation and coagulation assays revealed a normal specific activity for the rFVII-406Stop, rFVII-405Stop, rFVII-404Stop variants. Intriguingly, upon concentration of media, the specific activity of the rFVII-402Stop appeared to be 387±11% of rFVII-wt, thus recapitulating the mild coagulation phenotype of patients. Altogether these findings point toward multiple functional roles of the FVII carboxyl-terminal region, whose variation might have contributed to the divergence of this protein from the other coagulation serine proteases
Proteasome inhibitors: synthesis and activity of arecoline oxide tripeptide derivatives
No full textWe describe the synthesis and biological activities of a series of methyl 3,4-epoxypiperidine-3-carboxylate tripeptide derivatives that inhibit the chymotryptic and tryptic active sites of the 20S proteasome. Of the series, the compound containing 3-hydroxy-2-methylbenzoyl group at its N-terminal position, displayed the greatest inhibitory potency. All derivatives showed favourable pharmacokinetic properties
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