In approximately 15% of patients with acute myeloid leukemia (AML), total and phosphorylated EGFR proteins have been reported to be increased compared to healthy CD34
+
samples. However, it is ...unclear if this subset of patients would benefit from EGFR signaling pharmacological inhibition. Pre-clinical studies on AML cells provided evidence on the pro-differentiation benefits of EGFR inhibitors when combined with ATRA or ATO
in vitro
. Despite the success of ATRA and ATO in the treatment of patients with acute promyelocytic leukemia (APL), therapy-associated resistance is observed in 5-10% of the cases, pointing to a clear need for new therapeutic strategies for those patients. In this context, the functional role of EGFR tyrosine-kinase inhibitors has never been evaluated in APL. Here, we investigated the EGFR pathway in primary samples along with functional
in vitro
and
in vivo
studies using several APL models. We observed that total and phosphorylated EGFR (Tyr992) was expressed in 28% and 19% of blast cells from APL patients, respectively, but not in healthy CD34
+
samples. Interestingly, the expression of the EGF was lower in APL plasma samples than in healthy controls. The EGFR ligand AREG was detected in 29% of APL patients at diagnosis, but not in control samples.
In vitro
, treatment with the EGFR inhibitor gefitinib (ZD1839) reduced cell proliferation and survival of NB4 (ATRA-sensitive) and NB4-R2 (ATRA-resistant) cells. Moreover, the combination of gefitinib with ATRA and ATO promoted myeloid cell differentiation in ATRA- and ATO-resistant APL cells.
In vivo
, the combination of gefitinib and ATRA prolonged survival compared to gefitinib- or vehicle-treated leukemic mice in a syngeneic transplantation model, while the gain in survival did not reach statistical difference compared to treatment with ATRA alone. Our results suggest that gefitinib is a potential adjuvant agent that can mitigate ATRA and ATO resistance in APL cells. Therefore, our data indicate that repurposing FDA-approved tyrosine-kinase inhibitors could provide new perspectives into combination therapy to overcome drug resistance in APL patients.
The atmospheres of small, potentially rocky exoplanets are expected to cover a diverse range in composition and mass. Studying such objects therefore requires flexible and wide-ranging modeling ...capabilities. We present in this work the essential development steps that lead to our flexible radiative transfer module, REDFOX, and validate REDFOX for the solar system planets Earth, Venus, and Mars, as well as for steam atmospheres. REDFOX is a k-distribution model using the correlated-k approach with the random overlap method for the calculation of opacities used in the δ-two-stream approximation for radiative transfer. Opacity contributions from Rayleigh scattering, UV/visible cross sections, and continua can be added selectively. With the improved capabilities of our new model, we calculate various atmospheric scenarios for K2-18b, a super-Earth/sub-Neptune with ∼8 M⊕ orbiting in the temperate zone around an M star, with recently observed H2O spectral features in the infrared. We model Earth-like, Venus-like, and H2-He primary atmospheres of different solar metallicity and show resulting climates and spectral characteristics compared to observed data. Our results suggest that K2-18b has an H2-He atmosphere with limited amounts of H2O and CH4. Results do not support the possibility of K2-18b having a water reservoir directly exposed to the atmosphere, which would reduce atmospheric scale heights, and with it the amplitudes of spectral features, making the latter inconsistent with the observations. We also performed tests for H2-He atmospheres up to 50 times solar metallicity, all compatible with the observations.
Telomere length (TL) is a biomarker of cellular proliferative history. In healthy individuals, leukocyte TL shortens with age and associates with the lifespan of men and women. However, most of ...studies had used linear regression models to address the association of the TL attrition, aging and sex.
We evaluated the association between the TL, aging and sex in a cohort of 180 healthy subjects by quantile regression. The TL of nucleated blood cells was measured by fluorescent in situ hypridization (flow-FISH) in a cohort of 89 men, 81 women, and 10 umbilical cord samples. The results were validated by quantitative polymerase chain reaction (qPCR) and compared to a linear regression analysis.
By quantile regression, telomere dynamics slightly differed between sexes with aging: women had longer telomeres at birth and slower attrition rate than men until the sixth decade of life; after that, TL eroded faster and became shorter than that in men. These differences were not observed by linear regression analysis, as the overall telomere attrition rates in women and men were similar (42 pb per year, p < 0.0001 vs. 45 pb kb per year, p < 0.0001). Also, qPCR did not recapitulate flow-FISH findings, as the telomere dynamics by qPCR followed a linear model.
The quantile regression analysis accurately reproduced a third-order polynomial TL attrition rate in both women and men, but it depended on the technique applied to measure TL. The Flow-FISH reproduced the expected telomere dynamics through life and, differently from the qPCR, was able to detect the subtle TL variations associated with sex and aging.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We describe the preparation of monodisperse, lanthanide-doped hexagonal-phase NaYF4 upconverting luminescent nanoparticles for protein conjugation. Their core was coated with a silica shell which ...then was modified with a poly(ethylene glycol) spacer and N-hydroxysuccinimide ester groups. The nanoparticles were characterized by transmission electron microscopy, Raman spectroscopy, X-ray diffraction, and dynamic light scattering. The N-hydroxysuccinimide ester functionalization renders them highly reactive towards amine nucleophiles (e.g., proteins). We show that such particles can be conjugated to proteins. The protein-reactive UCLNPs and their conjugates to streptavidin and bovine serum albumin display multicolor emissions upon 980-nm continuous wave laser excitation. Surface plasmon resonance studies were carried out to prove bioconjugation and to compare the affinity of the particles for proteins immobilized on a thin gold film.
With the recent discoveries of terrestrial planets around active M-dwarfs, destruction processes masking the possible presence of life are receiving increased attention in the exoplanet community. We ...investigate potential biosignatures of planets having Earth-like (N2-O2) atmospheres orbiting in the habitable zone of the M-dwarf star AD Leo. These are bombarded by high energetic particles that can create showers of secondary particles at the surface. We apply our cloud-free 1D climate-chemistry model to study the influence of key particle shower parameters and chemical efficiencies of NOx and HOx production from cosmic rays. We determine the effect of stellar radiation and cosmic rays upon atmospheric composition, temperature, and spectral appearance. Despite strong stratospheric O3 destruction by cosmic rays, smog O3 can significantly build up in the lower atmosphere of our modeled planet around AD Leo related to low stellar UVB. The abundance of N2O decreases with increasing flaring energies but a sink reaction for N2O with excited oxygen becomes weaker, stabilizing its abundance. CH4 is removed mainly by Cl in the upper atmosphere for the strong flaring cases and not via hydroxyl as is otherwise usually the case. Cosmic rays weaken the role of CH4 in heating the middle atmosphere so that H2O absorption becomes more important. We additionally underline the importance of HNO3 as a possible marker for strong stellar particle showers. In a nutshell, uncertainty in NOx and HOx production from cosmic rays significantly influences the abundance of biosignatures and spectral appearance.
Summary
Stathmin 1 (STMN1) is a microtubule-destabilizing protein highly expressed in hematological malignancies and involved in proliferation and differentiation. Although a previous study found ...that the PML–RARα fusion protein, which contributes to the pathophysiology of acute promyelocytic leukemia (APL), positively regulates STMN1 at the transcription and protein activity levels, little is known about the role of STMN1 in APL. In this study, we aimed to investigate the
STMN1
expression levels and their associations with laboratory, clinical, and genomic data in APL patients. We also assessed the dynamics of STMN1 expression during myeloid cell differentiation and cell cycle progression, and the cellular effects of STMN1 silencing and pharmacological effects of microtubule-stabilizing drugs on APL cells. We found that
STMN1
transcripts were significantly increased in samples from APL patients compared with those of healthy donors (all
p
< 0.05). However, this had no effect on clinical outcomes.
STMN1
expression was associated with proliferation- and metabolism-related gene signatures in APL. Our data confirmed that STMN1 was highly expressed in early hematopoietic progenitors and reduced during cell differentiation, including the ATRA-induced granulocytic differentiation model. STMN1 phosphorylation was predominant in a pool of mitosis-enriched APL cells. In NB4 and NB4-R2 cells, STMN1 knockdown decreased autonomous cell growth (all
p
< 0.05) but did not impact ATRA-induced apoptosis and differentiation. Finally, treatment with paclitaxel (as a single agent or combined with ATRA) induced microtubule stabilization, resulting in mitotic catastrophe with repercussions for cell viability, even in ATRA-resistant APL cells. This study provides new insights into the STMN1 functions and microtubule dynamics in APL.
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CEKLJ, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Non-T cell activation linker (NTAL) is a lipid raft-membrane protein expressed by normal and leukemic cells and involved in cell signaling. In acute promyelocytic leukemia (APL), NTAL depletion from ...lipid rafts decreases cell viability through regulation of the Akt/PI3K pathway. The role of NTAL in APL cell processes, and its association with clinical outcome, has not, however, been established. Here, we show that reduced levels of NTAL were associated with increased all-trans retinoic acid (ATRA)-induced differentiation, generation of reactive oxygen species, and mitochondrial dysfunction. Additionally, NTAL-knockdown (NTAL-KD) in APL cell lines led to activation of Ras, inhibition of Akt/mTOR pathways, and increased expression of autophagy markers, leading to an increased apoptosis rate following arsenic trioxide treatment. Furthermore, NTAL-KD in NB4 cells decreased the tumor burden in (NOD scid gamma) NSG mice, suggesting its implication in tumor growth. A retrospective analysis of NTAL expression in a cohort of patients treated with ATRA and anthracyclines, revealed that NTAL overexpression was associated with a high leukocyte count (P = 0.007) and was independently associated with shorter overall survival (Hazard Ratio: 3.6; 95% Confidence Interval: 1.17-11.28; P = 0.026). Taken together, our data highlights the importance of NTAL in APL cell survival and response to treatment.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Abstract
NK cells mediate anti-leukemic immunosurveillance in AML. We hypothesized that impaired NK cells predict poor outcomes in AML. We analyzed the expression of receptors on CD56 NK cell subsets ...and their corresponding ligands on the CD45dim blast by flow cytometry in 100 AML and 17 healthy bone marrows. Risk stratification, complete remission, relapse, measurable residual disease, overall survival, relapse-free survival, NK cell ligand expression, NK function, and degranulation were evaluated. Additionally, we mapped the transcriptional landscape of AML-NK cells using single-cell RNA-seq. The expression of activating receptors by CD56dim NK was decreased in adverse risk, relapse, and MRD+ patients. Inhibitory receptors were increased in adverse risk, relapse, and MRD+. NK cell activating ligands were decreased in patients with higher expression of the corresponding receptor while inhibitory ligands were increased. Patients with a lower frequency of CD56dim NK showed less degranulation and killing rates. Transcriptionally, we observed an enrichment of inflammatory-associated pathways and an upregulation of inhibitory receptors in AML, especially in patients with the worst prognosis. Our data indicate that NK exhaustion, with a high frequency of inhibitory receptors, leads to impaired cytotoxicity and can predict poor outcomes in AML. Also, a selective pressure in the expression of NK cell ligands on the AML blast together with imbalanced receptors may vary in both NK and leukemic cells. Closing these gaps in the knowledge of NK-mediated immune evasion in leukemia is of significant interest for targeting the leukemic microenvironment by NK cell-mediated immunotherapy.
"division funds" - 3117175
O monitoramento da Leucemia Mieloide Aguda (LMA) é uma estratégia de avaliação prognóstica para identificar Doença Residual Mensurável (DRM). Indica-se o estudo de DRM por métodos moleculares em ...casos com mutações NPM1 /translocações tipo core-binding fator; mas a citometria de fluxo multiparamétrica (CFMP) é aplicável a mais de 90% das LMAs e preditora do sucesso terapêutico. Diante da escassez no acesso a métodos moleculares em países em desenvolvimento, um protocolo de determinação de DRM na rotina laboratorial é uma necessidade não atendida. Objetivamos implantar um protocolo de DRM por CFMP para LMA e avaliá-lo quanto à sua eficiência e como fator prognóstico adicional à estratificação de risco clássica. Foram incluídos 191 pacientes com LMA de novo ou secundária à síndrome mielodisplásica, entre 18 e 65 anos (09/2015 a 02/2023), com remissão morfológica completa após tratamento com 1 ou 2 ciclos de indução (ciclo 1:3 dias de daunorrubicina 60 mg/m2 e 7 dias de citarabina 200 mg/m2; ciclo 2:3 dias de daunorrubicina 60 mg/m2 e 6 dias de citarabina 1 g/m2 2x/dia). Na Consolidação foi administrada no ciclo1:citarabina 1 g/m2 2x/dia, 6 dias e no ciclo2: idem 1 ou transplante de Medula Óssea (MO) autólogo com condicionamento BuCy. Os pacientes foram estratificados (ELN2017*-exceto mutações TP53 ou ASXL1) de acordo com cariótipo, testes moleculares e coleta de dados clínicos. As DRMs 1, 2 (Pós-indução) e 4 (Pós consolidação), foram avaliadas com: CD45, CD34, CD117, CD33, CD38, CD19, CD123, CD7, CD56, CD13, CD11b, CD14, CD64, CD300e, CD15, CD133 e HLA-DR. Utilizamos a abordagem de LAIPs e DfN, comparando dados de MO saudável e diagnóstico e sendo DRM+ a frequência de células em CD45+ ≥ 0,1% (mínimo 1 fenótipo anormal). Analisamos Sobrevida Global e Livre de Recaída (SG e SLR) e Incidência Cumulativa de Recaída (ICR) - software R (α = 5%). Não foram encontradas associações entre DRM+ e idade, leucócitos, % de blastos, subtipo morfológico e alterações citogenéticas. Observou-se 21% de DRM+ na DRM1,13% na DRM2 e 12,5 % na DRM4. Na DRM1, a frequência de DRM+ para pacientes de risco baixo, intermediário e alto foi: 46,5%, 33,4%, 20,1% e nas DRMs 2 e 4, 33,4%/ 38,9%/ 27,7% e 48,8%/ 48,8%/ 14,4%, respectivamente. Globalmente as DRMs foram definidas como LAIPs ou DfN em 72,3% e 27,7% das amostras. A expressão de CD56 foi a mais frequente (22%), seguida por alterações em CD34/CD13 (21%) e CD33 (17%). DRMsnegativas foram mais frequentes em pacientes com NPM1mut (DRM1, 69,7%) do que em FLT3-ITD (15,2%). A DRM+ após o 2ºciclo de Indução implicou em maior risco de óbito (HR = 1329 (IC;75,16-235022), p = 0,002), maior ICR (44,5% em 30 meses, p = 0,033) e menor SG (4,4 meses, p = 0,018) no risco intermediário. A detecção de DRM+ não se associou aos riscos favorável e alto. Nossos achados demonstram a padronização da DRM por CFMP em uma população brasileira com tratamento único reprodutível usando painel racional com número limitado de marcadores. A detecção de fenótipos ao diagnóstico (LAIP) é mais útil do que os fenótipos semelhantes a DfN, embora sua combinação tenha validado o tubo proposto como “consenso”, aplicável a todos os casos a despeito do fenótipo inicial. Em pacientes de risco intermediário, o resultado da DRM por CFMP se mostrou fator de risco independente para SG. Sendo este grupo correspondente à cerca 1/3 dos casos, comumente com cariótipo normal e desfechos variáveis, a identificação de fatores prognósticos adicionais e dinâmicos tem grande utilidade e pode guiar as decisões terapêuticas. Por fim, a identificação dos fenótipos de DRM definidos neste protocolo pode contribuir na busca por alvos terapêuticos para erradicação das células leucêmicas resistentes.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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