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Mutations of the isocitrate dehydrogenase-1 (IDH1) and IDH2 genes are among the most frequent alterations in acute myeloid leukemia (AML) and can be found in ∼20% of patients at diagnosis. Among 4930 patients (median age, 56 years; interquartile range, 45-66) with newly diagnosed, intensively treated AML, we identified IDH1 mutations in 423 (8.6%) and IDH2 mutations in 575 (11.7%). Overall, there were no differences in response rates or survival for patients with mutations in IDH1 or IDH2 compared with patients without mutated IDH1/2. However, distinct clinical and comutational phenotypes of the most common subtypes of IDH1/2 mutations could be associated with differences in outcome. IDH1-R132C was associated with increased age, lower white blood cell (WBC) count, less frequent comutation of NPM1 and FLT3 internal tandem mutation (ITD) as well as with lower rate of complete remission and a trend toward reduced overall survival (OS) compared with other IDH1 mutation variants and wild-type (WT) IDH1/2. In our analysis, IDH2-R172K was associated with significantly lower WBC count, more karyotype abnormalities, and less frequent comutations of NPM1 and/or FLT3-ITD. Among patients within the European LeukemiaNet 2017 intermediate- and adverse-risk groups, relapse-free survival and OS were significantly better for those with IDH2-R172K compared with WT IDH, providing evidence that AML with IDH2-R172K could be a distinct entity with a specific comutation pattern and favorable outcome. In summary, the presented data from a large cohort of patients with IDH1/2 mutated AML indicate novel and clinically relevant findings for the most common IDH mutation subtypes.
Specialized surveillance mechanisms are essential to maintain the genetic integrity of germ cells, which are not only the source of all somatic cells but also of the germ cells of the next generation. DNA damage and chromosomal aberrations are, therefore, not only detrimental for the individual but affect the entire species. In oocytes, the surveillance of the structural integrity of the DNA is maintained by the p53 family member TAp63α. The TAp63α protein is highly expressed in a closed and inactive state and gets activated to the open conformation upon the detection of DNA damage, in particular DNA double-strand breaks. To understand the cellular response to DNA damage that leads to the TAp63α triggered oocyte death we have investigated the RNA transcriptome of oocytes following irradiation at different time points. The analysis shows enhanced expression of pro-apoptotic and typical p53 target genes such as CDKn1a or Mdm2, concomitant with the activation of TAp63α. While DNA repair genes are not upregulated, inflammation-related genes become transcribed when apoptosis is initiated by activation of STAT transcription factors. Furthermore, comparison with the transcriptional profile of the ΔNp63α isoform from other studies shows only a minimal overlap, suggesting distinct regulatory programs of different p63 isoforms.
The NADPH oxidase Nox4 is a hydrogen peroxide (H2O2)-producing enzyme, with the highest expression in the kidney. As the kidney is involved in volume and blood pressure control through sodium handling, we set out to determine the impact of a low sodium diet on these parameters in WT and Nox4-/- mice. Nox4 expression in the murine kidney was restricted to the proximal tubule. Nevertheless, low-sodium-induced weight loss and sodium sparing function was similar in WT and Nox4-/- mice, disputing an important function of renal Nox4 in sodium handling. In contrast, a low sodium diet resulted in a reduction in systolic blood pressure in Nox4-/- as compared to WT mice. This was associated with a selectively lower pressure to heart-rate ratio, as well as heart to body weight ratio. In general, a low sodium diet leads to activation of sympathetic tone and the renin angiotensin system, which subsequently increases peripheral resistance. Our observations suggest that the control by this system is attenuated in Nox4-/- mice, resulting in lower blood pressure in response to low sodium.
Der Erfolg einer nationalen Forschungsdateninfrastruktur hängt von der Einbindung der gesamten Wissenschaftsgemeinschaft und -infrastruktur ab. In zahlreichen Bundesländern existieren Landesinitiativen für Forschungsdatenmanagement oder ähnliche Einrichtungen, die dazu beitragen können, diese Einbindung zu erreichen. Das gemeinsame Papier von Vertretern aus verschiedenen Bundesländern argumentiert, dass eine enge Verknüpfung der Landesinitiativen mit dem NFDI e.V. erfolgen sollte, um die Potentiale der Zusammenarbeit zu nutzen.
Der NFDI e. V. wird einen bedeutsamen Beitrag für einen besseren Umgang mit Forschungsdaten leisten, doch der Erfolg der nationalen Forschungsdateninfrastruktur ist letztlich von einer Einbindung der gesamten Wissenschaftsgemeinschaft und -infrastruktur abhängig. Die vielfältigen Forschungseinrichtungen einzubinden, erfordert Koordination auf vielen Ebenen. Speziell Hochschulen haben eine tragende Rolle für sowohl disziplinäre und interdisziplinäre Forschung als auch wissenschaftliche Ausbildung in Deutschland und sind damit zentrale Akteure für die fachübergreifende Forschungsdateninfrastruktur. Durch die Förderung von Kooperationen und Koordination auf Ebene von Ländern oder Länderverbünden lässt sich die Entwicklung der nationalen Forschungsdateninfrastruktur unterstützen. Landesinitiativen für Forschungsdatenmanagement (FDM) oder ähnliche koordinierende Einrichtungen können die digitale Transformation in der Forschung durch Information, den Aufbau von Kooperationen und die Qualifikation von Personal unterstützen. Ihre Einrichtung, dauerhafte Etablierung und Einbeziehung in die Arbeit des NFDI e. V. ist ein wichtiger Beitrag zur Schaffung einer nationalen Forschungsdateninfrastruktur.
Oxidative stress is thought to be a driver for several diseases. However, many data to support this concept were obtained by the addition of extracellular H2O2 to cells. This does not reflect the dynamics of intracellular redox modifications. Cells actively control their redox-state, and increased formation of ROS is a response to cellular stress situations such as chronic inflammation.
In this study, it was shown that different types of ROS lead to different metabolic and transcriptomic responses of HUVECs. While 300 μM extracellular H2O2 led to substantial metabolic and transcriptomic changes, the effects of DAO-derived H2O2 and menadione were low to moderate, indicating that the source and the concentration of ROS are important in eliciting changes in metabolism and gene expression.
Specifically, it was identified that acute increases in ROS transiently inactivate the enzyme ω-amidase/NIT2 of the glutaminase II pathway, which supplies cells with anaplerotic α-ketoglutarate. The pathway has not been studied systematically because, as noted above, the major intermediate, KGM, is not commercially available. In the present study, an internal standard for targeted detection of KGM in cells and blood plasma/serum was used. Deletion of NIT2 by CRISPR/Cas9 significantly reduced α-ketoglutarate levels in HUVECs and elevated KGM levels. It appears that in cell culture conditions, hydrolysis of KGM to α-ketoglutarate is very efficient. Knockout of the glutamine transaminases significantly reduced methionine, suggesting that the glutaminase II pathway is an important source of amino acid replenishment.
Similar to genetic silencing of GLS1 [91,92], HUVECs lacking NIT2 showed reduced proliferation and angiogenic sprouting. Furthermore, our results indicate that, at least in HUVECs, the enzyme also locates in the mitochondria where it interacts with key enzymes of glutamine/glutamate/α-ketoglutarate metabolism.
The data of the present work indicate that the glutaminase II pathway is an underappreciated, redox-sensitive pathway for glutamine utilization in HUVECs. Genetic deletion of NIT2 has considerable physiological effects highlighting the importance of glutamine for ECs.
The antibody-drug conjugate polatuzumab vedotin (pola) has recently been approved in combination with bendamustine and rituximab (pola-BR) for patients with refractory or relapsed (r/r) large B-cell lymphoma (LBCL). To investigate the efficacy of pola-BR in a real-world setting, we retrospectively analyzed 105 patients with LBCL who were treated in 26 German centers under the national compassionate use program. Fifty-four patients received pola as a salvage treatment and 51 patients were treated with pola with the intention to bridge to chimeric antigen receptor (CAR) T-cell therapy (n = 41) or allogeneic hematopoietic cell transplantation (n = 10). Notably, patients in the salvage and bridging cohort had received a median of 3 prior treatment lines. In the salvage cohort, the best overall response rate was 48.1%. The 6-month progression-free survival and overall survival (OS) was 27.7% and 49.6%, respectively. In the bridging cohort, 51.2% of patients could be successfully bridged with pola to the intended CAR T-cell therapy. The combination of pola bridging and successful CAR T-cell therapy resulted in a 6-month OS of 77.9% calculated from pola initiation. Pola vedotin-rituximab without a chemotherapy backbone demonstrated encouraging overall response rates up to 40%, highlighting both an appropriate alternative for patients unsuitable for chemotherapy and a new treatment option for bridging before leukapheresis in patients intended for CAR T-cell therapy. Furthermore, 7 of 12 patients with previous failure of CAR T-cell therapy responded to a pola-containing regimen. These findings suggest that pola may serve as effective salvage and bridging treatment of r/r LBCL patients.
Simple Summary: Acute myeloid leukemia (AML) is a genetically heterogeneous disease. Clinical phenotypes of frequent mutations and their impact on patient outcome are well established. However, the role of rare mutations often remains elusive. We retrospectively analyzed 1529 newly diagnosed and intensively treated AML patients for mutations of BCOR and BCORL1. We report a distinct co-mutational pattern that suggests a role in disease progression rather than initiation, especially affecting mechanisms of DNA-methylation. Further, we found loss-of-function mutations of BCOR to be independent markers of poor outcomes in multivariable analysis. Therefore, loss-of-function mutations of BCOR need to be considered for AML management, as they may influence risk stratification and subsequent treatment allocation.
Abstract: Acute myeloid leukemia (AML) is characterized by recurrent genetic events. The BCL6 corepressor (BCOR) and its homolog, the BCL6 corepressor-like 1 (BCORL1), have been reported to be rare but recurrent mutations in AML. Previously, smaller studies have reported conflicting results regarding impacts on outcomes. Here, we retrospectively analyzed a large cohort of 1529 patients with newly diagnosed and intensively treated AML. BCOR and BCORL1 mutations were found in 71 (4.6%) and 53 patients (3.5%), respectively. Frequently co-mutated genes were DNTM3A, TET2 and RUNX1. Mutated BCORL1 and loss-of-function mutations of BCOR were significantly more common in the ELN2017 intermediate-risk group. Patients harboring loss-of-function mutations of BCOR had a significantly reduced median event-free survival (HR = 1.464 (95%-Confidence Interval (CI): 1.005–2.134), p = 0.047), relapse-free survival (HR = 1.904 (95%-CI: 1.163–3.117), p = 0.01), and trend for reduced overall survival (HR = 1.495 (95%-CI: 0.990–2.258), p = 0.056) in multivariable analysis. Our study establishes a novel role for loss-of-function mutations of BCOR regarding risk stratification in AML, which may influence treatment allocation.
Reactive oxygen species (ROS) are important mediators of both physiological and pathophysiological signal transduction in the cardiovascular system. The effects of ROS on cellular processes depend on the concentration, localization, and duration of exposure. Cellular stress response mechanisms have evolved to mitigate the negative effects of acute oxidative stress. In this study, we investigate the short-term and long-term metabolic and transcriptomic response of human umbilical vein endothelial cells (HUVEC) to different types and concentrations of ROS. To generate intracellular H2O2, we utilized a lentiviral chemogenetic approach for overexpression of human D-amino acid oxidase (DAO). DAO converts D-amino acids into their corresponding imino acids and H2O2. HUVEC stably overexpressing DAO (DAO-HUVEC) were exposed to D-alanine (3 mM), exogenous H2O2 (10 µM or 300 µM), or menadione (5 µM) for various timepoints and subjected to global untargeted metabolomics (LC-MS/MS) and RNAseq by MACE (Massive analysis of cDNA ends). A total of 300 µM H2O2 led to pronounced changes on both the metabolic and transcriptomic level. In particular, metabolites linked to redox homeostasis, energy-generating pathways, and nucleotide metabolism were significantly altered. Furthermore, 300 µM H2O2 affected genes related to the p53 pathway and cell cycle. In comparison, the effects of menadione and DAO-derived H2O2 mainly occurred at gene expression level. Collectively, all types of ROS led to subtle changes in the expression of ribosomal genes. Our results show that different types and concentration of ROS lead to a different metabolic and transcriptomic response in endothelial cells.
Epoxyeicosatrienoic acids (EETs) are signaling lipids produced by the cytochrome P450-(CYP450)-mediated epoxygenation of arachidonic acid. EETs have numerous biological effects on the vascular system, but aspects including their species specificity make their effects on vascular tone controversial. CYP450 enzymes require the 450-reductase (POR) for their activity. We set out to determine the contribution of endothelial CYP450 to murine vascular function using isolated aortic ring preparations from tamoxifen-inducible endothelial cell-specific POR knockout mice (ecPOR−/−). Constrictor responses to phenylephrine were similar between control (CTR) and ecPOR−/− mice. Contrastingly, sensitivity to the thromboxane receptor agonist U46619 and prostaglandin E2 (PGE2) was increased following the deletion of POR. Ex vivo incubation with a non-hydrolyzable EET (14,15-EE-8(Z)-E, EEZE) reversed the increased sensitivity to U46619 to the levels of CTR. EETs had no effect on vascular tone in phenylephrine-preconstricted vessels, but dilated vessels contracted with U46619 or PGE2. As U46619 acts through RhoA-dependent kinase, this system was analyzed. The deletion of POR affected the expression of genes in this pathway and the inhibition of Rho-GTPase with SAR407899 decreased sensitivity to U46619. These data suggest that EET and prostanoid crosstalk at the receptor level and that lack of EET production sensitizes vessels to vasoconstriction via the induction of the Rho kinase system.