Rearrangements of ATP5L-KMT2A in acute lymphoblastic leukaemia

Recent genomic studies have identified a wide range of novel genetic alterations that have substantially increased our knowledge of the biology of B- and T-progenitor acute lymphoblastic leukaemia (B-ALL, T-ALL) and defined new subtypes with prognostic and therapeutic relevance.1-4 Thanks to the use of transcriptome sequencing approaches, new cryptic fusion transcripts have been described, such as the ATP5L-KMT2A gene fusion, described by Gestrich et al. in a 14-month-old patient with aggressive B-ALL.5 ATP5L or ATP5MG (ATP Synthase Membrane Subunit G) catalyzes ATP synthesis during oxidative phosphorylation.6 This protein has recently been reported to interact with a SARS-CoV-2 protein.7 The histone lysine [K]-methyl transferase 2A (KMT2A) gene is a transcriptional coactivator that plays an essential role in regulating gene expression during early development and haematopoiesis. It is frequently rearranged to over 135 translocation partner genes in acute leukaemias.8 ATP5L is a novel KMT2A fusion partner not detectable by fluorescent in situ hybridization (FISH) or karyotype, due to the closeness of the two genes on chromosome 11q23. The Cleveland Medical Centre team found a reciprocal out-of-frame ATP5L-KMT2A rearrangement that juxtaposes the ATP5L exon 1 to the KMT2A exon 2, with the insertion of an extra nucleotide (G) at the fusion site.5 We sequenced leukaemic cells from eight adult ALL patients (two T-ALL, five B-ALL Philadelphia negative (Ph−) and one B-ALL Ph+; Table I) by a 199 gene RNA-sequencing panel (RNA-seq; Pan-Heme FusionPlex, ArcherDx Inc., Boulder, CO, USA).The study was supported by European Union Seventh Framework Programme (FP7/2007-2013) (GA 306242-NGS-PTL) and Associazione Italiana Leucemie (AIL)

Dynamic numerical analysis of composite plates and shells with geometrical nonlinearity.

The paper presents the main features of a finite element numerical model for transient dynamic analysis of composite laminated plates and shells, including geometrical nonlinearity and a simplified contact model to allow simulation of impact events. The model has been implemented in a program written in Fortran language. Some examples of analyses performed with the program are described and discussed

Some issues concerning the dynamic response and damage of composite laminates subjected to low velocity impact

Abstract. This thesis presents a discussion on a few specific topics regarding the low velocity impact behaviour of laminated composites. These topics were chosen because of their significance as well as the relatively limited attention received so far by the scientific community. The first issue considered is the comparison between the effects induced by a low velocity impact and by a quasi-static indentation experimental test. An analysis of both test conditions is presented, based on the results of experiments carried out on carbon fibre laminates and on numerical computations by a finite element model. It is shown that both quasi-static and dynamic tests led to qualitatively similar failure patterns; three characteristic contact force thresholds, corresponding to the main steps of damage progression, were identified and found to be equal for impact and indentation. On the other hand, an equal energy absorption resulted in a larger delaminated area in quasi-static than in dynamic tests, while the maximum displacement of the impactor (or indentor) was higher in the case of impact, suggesting a probably more severe fibre damage than in indentation. Secondly, the effect of different specimen dimensions and boundary conditions on its impact response was examined. Experimental testing showed that the relationships of delaminated area with two significant impact parameters, the absorbed energy and the maximum contact force, did not depend on the in-plane dimensions and on the support condition of the coupons. The possibility of predicting, by means of a simplified numerical computation, the occurrence of delaminations during a specific impact event is also discussed. A study about the compressive behaviour of impact damaged laminates is also presented. Unlike most of the contributions available about this subject, the results of compression after impact tests on thin laminates are described in which the global specimen buckling was not prevented. Two different quasi-isotropic stacking sequences, as well as two specimen geometries, were considered. It is shown that in the case of rectangular coupons the lay-up can significantly affect the damage induced by impact. Different buckling shapes were observed in laminates with different stacking sequences, in agreement with the results of numerical analysis. In addition, the experiments showed that impact damage can alter the buckling mode of the laminates in certain situations, whereas it did not affect the compressive strength in every case, depending on the buckling shape. Some considerations about the significance of the test method employed are also proposed. Finally, a comprehensive study is presented regarding the influence of pre-existing in-plane loads on the impact response of laminates. Impact events in several conditions, including both tensile and compressive preloads, both uniaxial and biaxial, were analysed by means of numerical finite element simulations; the case of laminates impacted in postbuckling conditions was also considered. The study focused on how the effect of preload varies with the span-to-thickness ratio of the specimen, which was found to be a key parameter. It is shown that a tensile preload has the strongest effect on the peak stresses at low span-to-thickness ratios, leading to a reduction of the minimum impact energy required to initiate damage, whereas this effect tends to disappear as the span-to-thickness ratio increases. On the other hand, a compression preload exhibits the most detrimental effects at medium span-to-thickness ratios, at which the laminate compressive strength and the critical instability load are close to each other, while the influence of preload can be negligible for thin plates or even beneficial for very thick plates. The possibility to obtain a better explanation of the experimental results described in the literature, in view of the present findings, is highlighted. Throughout the thesis the capabilities and limitations of the finite element model, which was implemented in an in-house program, are discussed. The program did not include any damage model of the material. It is shown that, although this kind of analysis can yield accurate results as long as damage has little effect on the overall mechanical properties of a laminate, it can be helpful in explaining some phenomena and also in distinguishing between what can be modelled without taking into account the material degradation and what requires an appropriate simulation of damage. Sommario. Questa tesi presenta una discussione su alcune tematiche specifiche riguardanti il comportamento dei compositi laminati soggetti ad impatto a bassa velocità. Tali tematiche sono state scelte per la loro importanza, oltre che per l’attenzione relativamente limitata ricevuta finora dalla comunità scientifica. La prima delle problematiche considerate è il confronto fra gli effetti prodotti da una prova sperimentale di impatto a bassa velocità e da una prova di indentazione quasi statica. Viene presentata un’analisi di entrambe le condizioni di prova, basata sui risultati di esperimenti condotti su laminati in fibra di carbonio e su calcoli numerici svolti con un modello ad elementi finiti. È mostrato che sia le prove quasi statiche sia quelle dinamiche portano a un danneggiamento con caratteristiche qualitativamente simili; tre valori di soglia caratteristici della forza di contatto, corrispondenti alle fasi principali di progressione del danno, sono stati individuati e stimati uguali per impatto e indentazione. D’altro canto lo stesso assorbimento di energia ha portato ad un’area delaminata maggiore nelle prove statiche rispetto a quelle dinamiche, mentre il massimo spostamento dell’impattatore (o indentatore) è risultato maggiore nel caso dell’impatto, indicando la probabilità di un danneggiamento delle fibre più severo rispetto al caso dell’indentazione. In secondo luogo è stato esaminato l’effetto di diverse dimensioni del provino e diverse condizioni al contorno sulla sua risposta all’impatto. Le prove sperimentali hanno mostrato che le relazioni fra l’area delaminata e due parametri di impatto significativi, l’energia assorbita e la massima forza di contatto, non dipendono dalle dimensioni nel piano dei provini e dalle loro condizioni di supporto. Viene anche discussa la possibilità di prevedere, per mezzo di un calcolo numerico semplificato, il verificarsi di delaminazioni durante un determinato caso di impatto. È presentato anche uno studio sul comportamento a compressione di laminati danneggiati da impatto. Diversamente della maggior parte della letteratura disponibile su questo argomento, vengono qui descritti i risultati di prove di compressione dopo impatto su laminati sottili durante le quali l’instabilità elastica globale dei provini non è stata impedita. Sono state considerate due differenti sequenze di laminazione quasi isotrope, oltre a due geometrie per i provini. Viene mostrato come nel caso di provini rettangolari la sequenza di laminazione possa influenzare sensibilmente il danno prodotto dall’impatto. Due diversi tipi di deformate in condizioni di instabilità sono stati osservati per laminati con diversa laminazione, in accordo con i risultati dell’analisi numerica. Gli esperimenti hanno mostrato inoltre che in certe situazioni il danno da impatto può alterare la deformata che il laminato assume in seguito ad instabilità; d’altra parte tale danno non ha sempre influenzato la resistenza a compressione, a seconda della deformata. Vengono proposte anche alcune considerazioni sulla significatività del metodo di prova utilizzato. Infine viene presentato uno studio esaustivo riguardo all’influenza di carichi membranali preesistenti sulla risposta all’impatto dei laminati. Sono stati analizzati con simulazioni numeriche ad elementi finiti casi di impatto in diverse condizioni di precarico, sia di trazione sia di compressione, sia monoassiali sia biassiali; è stato preso in considerazione anche il caso di laminati impattati in condizioni di postbuckling. Lo studio si è concentrato in particolare sulla dipendenza degli effetti del precarico dal rapporto larghezza-spessore del provino, che si è rivelato un parametro fondamentale. Viene illustrato che un precarico di trazione ha l’effetto più marcato sulle massime tensioni per bassi rapporti larghezza-spessore, portando ad una riduzione della minima energia di impatto necessaria per innescare il danneggiamento, mentre questo effetto tende a scomparire all’aumentare di tale rapporto. Il precarico di compressione evidenzia invece gli effetti più deleteri a rapporti larghezza-spessore intermedi, ai quali la resistenza a compressione del laminato e il suo carico critico di instabilità sono paragonabili, mentre l’influenza del precarico può essere trascurabile per piastre sottili o addirittura benefica per piastre molto spesse. Viene evidenziata la possibilità di trovare una spiegazione più soddisfacente dei risultati sperimentali riportati in letteratura, alla luce del presente contributo. Nel corso della tesi vengono anche discussi le potenzialità ed i limiti del modello ad elementi finiti utilizzato, che è stato implementato in un programma scritto in proprio. Il programma non comprende alcuna modellazione del danneggiamento del materiale. Viene però spiegato come, nonostante questo tipo di analisi possa portare a risultati accurati soltanto finché il danno ha scarsi effetti sulle proprietà meccaniche d’insieme del laminato, esso possa essere utile per spiegare alcuni fenomeni, oltre che per distinguere fra ciò che si può riprodurre senza tenere conto del degrado del materiale e ciò che invece richiede una simulazione adeguata del danneggiamento

EXPERIMENTAL DETERMINATION OF THE TORSIONAL RESIDUAL STRENGTH AFTER IMPACT OF CFRP TUBES

In this paper the residual strength to torsion of carbon fibre reinforced plastic tubes, of different lay-ups, after a low velocity lateral impact was experimentally measured and compared with the resistance of undamaged tubes in order to develop suitable design criteria

Low-velocity impact behavior of vitreous-enameled steel plates

In the present work vitreous enamel, a special class of ceramic–glass material, was used as a coating for thin steel plate. The impact behavior of rectangular steel plate and coated steel plate (enameled steel plate) was studied by means of both experimental tests and numerical analysis. Experimental tests revealed the onset and growth of plate instability in the case of impact both on steel plates and on enameled steel plates. The instability was mainly located on the free edges and was particularly evident on the longer side of rectangular plates. The impactor initial energy that caused the instability onset in the case of enameled steel plate was about six times higher than the one that induced the instability in the steel plates. Numerical simulations were performed to better understand and study the experimentally observed instability phenomenon. Four numerical models were developed in order to study the influence of plate thickness and residual stresses acting on the enameled steel plates on plate instability. Results of numerical simulation revealed that residual stresses acting on enameled steel plated increased the value of force that caused the instability onset. Further numerical simulations showed that the increase of residual stresses acting on enameled steel plates highlighted the values relative to the instability force increase according to a non-linear trend

Respiratory complex I null cancer cells and molecular docking reveal specificity and mode of action inhibitors with anticancer activity

Respiratory complex I (NADH:ubiquinone oxidoreductase; EC 1.6.5.3; CI) derangement or inhibition have shown to slow down tumor growth, confining aggressive tumors into a low proliferative state and opening a possible window for additional therapeutic intervention. Hence, this enzyme has emerged as an attractive druggable target for cancer treatment and several inhibitors have been proposed as possible therapeutic agents in different experimental preclinical settings. However, none of them is currently used in clinical practice and several open issues remain, including their mechanism of action, efficacy and specificity. We here investigated the specificity and the antiproliferative activity of three inhibitors (metformin, BAY 87-2243 and EVP 4593) using unique models lacking CI generated in different cancer cell background, namely colon cancer, ovarian cancer and melanoma. In these models, the antiproliferative effect of metformin resulted independent from CI inhibition, while both BAY 87-2243 and EVP 4593 were highly selective at optimized concentrations fully inhibiting mitochondrial respiration. Molecular docking predictions indicated such high efficiency may derive from the tight network of interactions in the quinone binding site, where EVP 4593 was foreseen to interact with amino acids from nuclear subunits forming the deep site, while BAY 87-2243 is predicted to bind in the shallow site. Our data prompt for caution when referring to metformin as CI targeting compound and highlight the need of dosage optimization and careful evaluation of molecular interactions between inhibitors and CI. Amino acids involved in the interactions with EVP 4593 and BAY 87-2243 may be subjected to polymorphic variants, both inherited or somatic, although with low allele frequency. Hence, aiming at a personalized medicine approach, genotyping is suggested before treatment with these compounds, especially those binding the shallow quinone binding site where ND1 plays a major contribution

NDUFS3 knockout cancer cells and molecular docking reveal specificity and mode of action of anti-cancer respiratory complex I inhibitors

Inhibition of respiratory complex I (CI) is becoming a promising anti-cancer strategy, encouraging the design and the use of inhibitors, whose mechanism of action, efficacy and specificity remain elusive. As CI is a central player of cellular bioenergetics, a finely tuned dosing of targeting drugs is required to avoid side effects. We compared the specificity and mode of action of CI inhibitors metformin, BAY 87-2243 and EVP 4593 using cancer cell models devoid of CI. Here we show that both BAY 87-2243 and EVP 4593 were selective, while the antiproliferative effects of metformin were considerably independent from CI inhibition. Molecular docking predictions indicated that the high efficiency of BAY 87-2243 and EVP 4593 may derive from the tight network of bonds in the quinone binding pocket, although in different sites. Most of the amino acids involved in such interactions are conserved across species and only rarely found mutated in human. Our data make a case for caution when referring to metformin as a CI-targeting compound, and highlight the need for dosage optimization and careful evaluation of molecular interactions between inhibitors and the holoenzyme

Immunosuppressive Treg cells acquire the phenotype of effector-T cells in chronic lymphocytic leukemia patients

Background: In chronic lymphocytic leukemia (CLL) disease onset and progression are influenced by the behavior of specific CD4+T cell subsets, such as T regulatory cells (Tregs). Here, we focused on the phenotypic and functional characterization of Tregs in CLL patients to improve our understanding of the putative mechanism by which these cells combine immunosuppressive and effector-like properties. Methods: Peripheral blood mononuclear cells were isolated from newly diagnosed CLL patients (n = 25) and healthy volunteers (n = 25). The phenotypic and functional characterization of Tregs and their subsets was assessed by flow cytometry. In vitro analysis of TH1, TH2, TH17 and Tregs cytokines was evaluated by IFN-γ, IL-4, IL-17A and IL-10 secretion assays. The transcriptional profiling of 84 genes panel was evaluated by RT2Profiler PCR Array. Statistical analysis was carried out using exact non parametric Mann-Whitney U test. Results: In all CLL samples, we found a significant increase in the frequency of IL-10-secreting Tregs and Tregs subsets, a significant rise of TH2 IL-4+and TH17 IL-17A+cells, and a higher percentage of IFN-γ/IL-10 and IL-4/IL-10 double-releasing CD4+T cells. In addition, we also observed the up-regulation of innate immunity genes and the down-regulation of adaptive immunity ones. Conclusions: Our data show that Tregs switch towards an effector-like phenotype in CLL patients. This multifaceted behavior is accompanied by an altered cytokine profiling and transcriptional program of immune genes, leading to a dysfunction in immune response in the peripheral blood environment of CLL patients