Novel functions of aberrant cyclin D1/CDK4 activity in mantle cell lymphoma and consequences for proteasome inhibitor treatment

Mantle cell lymphoma (MCL) is an aggressive B cell-non-Hodgkin lymphoma with generally poor outcome and only transient responses to conventional chemotherapy. Cells of MCL patients are characterized by an aberrant high cyclin D1-driven cyclin-dependent kinase 4 (CDK4) activity. Recently, the ubiquitin proteasome system (UPS) inhibitor bortezomib has been approved for the treatment of relapsed/refractory MCL and has shown promising results in first-line treatment of MCL patients. However, little is known about how the aberrant cyclin D1-driven CDK4 activity does affect the treatment efficacy of UPS inhibitors in MCL. The present work aimed to identify novel functions for cyclin D1/CDK4 activity in MCL that regulate the efficacy of proteasome inhibitor treatment. In this study, the efficacy of proteasome inhibitor treatment was found to depend on the aberrant cyclin D1/CDK4 activity in MCL. Inhibition of cyclin D1/CDK4 activity with the CDK4 inhibitor palbociclib antagonized bortezomib induced cell death in MCL cells. Moreover, the antioxidant defense protein sestrin 3 was identified to be strongly regulated by cyclin D1-driven CDK4 activity. Although, bortezomib efficacy was demonstrated to be regulated by reactive oxygen species (ROS) or antioxidants, changes in sestrin 3 expression levels are not responsible for cell death regulation after UPS blockage in MCL. Furthermore, even though targeting cyclin D1/CDK4 activity with palbociclib induces cell cycle arrest, changes in cell cycle distribution after cyclin D1/CDK4 inhibition also do not mediate the antagonizing effect on bortezomib induced cell death. Astonishingly, it could be demonstrated that cyclin D1/CDK4 inhibition antagonizes the bortezomib induced cell death through a reduction of NOXA protein accumulation. It could also be shown that this mechanism is not exclusive for the proteasome inhibitor bortezomib but also applies to other agents that depend on NOXA protein accumulation for efficient cell death induction in MCL cells. Importantly, results of the present study revealed that this regulation of NOXA protein levels by cyclin D1/CDK4 activity is not associated with a reduction of NOXA transcript levels but is mediated by the regulation of NOXA protein stability. This identified novel function of cyclin D1/CDK4 to regulate NOXA protein half-life in the presence of UPS blockage is mediated by the autophagic degradation machinery. This study identified, the regulation of autophagic activity as a novel cell cycle independent function of cyclin D1/CDK4 activity in MCL. In this context, it was demonstrated that inhibition of cyclin D1/CDK4 activity by palbociclib treatment induces autophagic activity in MCL. Cyclin D1/CDK4 and autophagic activity, however, are not linked by the common autophagy regulating pathways, AMP-activated protein kinase (AMPK) or ROS. In addition, genetic or pharmacological inhibition of autophagic activity reverses the palbociclib mediated antagonism on bortezomib induced cell death and NOXA protein accumulation. Remarkably, this study demonstrates that the NOXA protein can be targeted for proteasomal as well as autophagosomal degradation. Targeting NOXA protein for degradation through selective autophagy might be mediated through a LC3-interacting region (LIR) motif that was identified in the amino acid sequence of the NOXA protein. Interestingly, combination of bortezomib with known autophagy inhibitors potentiates cell death induction as well as NOXA protein accumulation compared to bortezomib treatment alone. Furthermore, screening for a highly efficient combinatorial blockade of the UPS and the ALP revealed that the fatty acid synthase (FASN) inhibitor orlistat can be repositioned for autophagy inhibition. Consequently, the combinatorial treatment with bortezomib and orlistat leads to a very efficient NOXA protein induction and caspase dependent cell death in MCL cells. This cell death is again dependent on the aberrant high cyclin D1/CDK4 activity. The expression levels of certain other apoptotic proteins, however, are not affected by the combinatorial treatment. In conclusion, the present study revealed the regulation of autophagic activity as a novel function of cyclin D1/CDK4 activity in MCL. These findings are of utmost importance for the treatment of MCL patients, as combination of proteasome inhibitors with autophagy inhibitors could greatly improve therapy outcomes or overcome bortezomib resistances. In addition to known autophagy inhibitors, treatment options could include conventional drugs that are repurposed for targeting the autophagic degradation machinery. On the other hand, care must be taken when combining proteasome inhibitors with other chemotherapeutics that might impair cyclin D1/CDK4 activity or induce autophagy.Das Mantelzell-Lymphom (MCL) ist ein aggressives B-Zell-Non-Hodgkin-Lymphom mit sehr schlechter klinischer Prognose und nur zeitweiligem Ansprechen auf konventionelle Chemotherapie. Zellen von MCL-Patienten zeichnen sich durch eine anormal hohe Cyclin D1-vermittelte Cyclin-abhängige Kinase 4 (CDK4) Aktivität aus. Kürzlich wurde der Ubiquitin-Proteasom-System (UPS)-Inhibitor Bortezomib für die Behandlung des rezidivierten bzw. refraktären MCl zugelassen und zeigte vielversprechende Ergebnisse unter anderem in der Primärtherapie von MCL-Patienten. Es ist jedoch wenig darüber bekannt, wie die anormale Cyclin D1/CDK4-Aktivität beim MCL die Wirksamkeit der Behandlung von UPS-Inhibitoren beeinflusst. Ziel der vorliegenden Arbeit war es daher neue Funktionen für die Cyclin D1/CDK4 Aktivität im MCL zu identifizieren, die die Wirksamkeit der Behandlung von Proteasominhibitoren beeinflussen. In dieser Arbeit konnte gezeigt werden, dass die Wirksamkeit der Proteasominhibitoren von der anormalen Cyclin D1/CDK4-Aktivität in MCL-Zellen abhängig ist. Außerdem wurde nachgewiesen, dass das Antioxidans-Protein Sestrin 3 durch die Cyclin D1-vermittelte CDK4-Aktivität reguliert wird. Es konnte dabei gezeigt werden, dass die Wirksamkeit von Bortezomib durch reaktive Sauerstoffspezies (ROS) oder Antioxidantien reguliert wird. Dennoch sind Veränderungen der Sestrin 3 Expressionslevel nicht für die Regulation des Zelltods nach UPS-Blockade im MCL verantwortlich. Obwohl die Hemmung der Cyclin D1/CDK4-Aktivität durch Palbociclib einen Zellzyklusarrest induziert, vermitteln diese Veränderungen im Zellzyklus nicht die antagonisierende Wirkung von Palbociclib auf den Bortezomib induzierten Zelltod. Erstaunlicherweise konnte gezeigt werden, dass Palbociclib den Bortezomib induzierten Zelltod durch eine reduzierte NOXA-Proteinakkumulation antagonisiert. Es konnte außerdem nachgewiesen werden, dass dieser Mechanismus nicht nur auf den Proteasominhibitor Bortezomib beschränkt ist, sondern auch für andere Wirkstoffe gilt, die für eine effiziente Zelltodinduktion im MCL auf die Akkumulation des NOXA-Proteins angewiesen sind. Wichtig ist hierbei, dass die Cyclin D1/CDK4 vermittelte Regulierung der NOXA-Proteinexpression, nicht durch eine Reduzierung des NOXA-Transkripts, sondern durch eine Regulierung der NOXA-Proteinstabilität vermittelt wird. Diese Funktion von Cyclin D1/CDK4, die Halbwertszeit des NOXA-Proteins in Anwesenheit einer UPS-Blockade zu regulieren, wird hierbei durch die autophagosomalen Abbauwege vermittelt. Die Regulation der autophagosomalen Aktivität wurde im Rahmen dieser Arbeit, als eine neue zellzyklusunabhängige Funktion der Cyclin D1/CDK4 Aktivität im MCL identifiziert. In diesem Zusammenhang wurde gezeigt, dass die Hemmung der Cyclin D1/CDK4 Aktivität durch die Behandlung mit Palbociclib, die autophagosomale Aktivität im MCL erhöht. Cyclin D1/CDK4 und autophagosomale Aktivität stehen jedoch nicht durch die Signalwege miteinander in Verbindung, die üblicherweise Autophagie regulieren, wie die AMP aktivierte Proteinkinase (AMPK)- oder ROS Signalwege. Des Weiteren hob die genetische oder pharmakologische Hemmung der autophagosomalen Aktivität, den durch Palbociclib vermittelten Antagonismus auf den Bortezomib induzierten Zelltod und die NOXA-Proteinakkumulation auf. Erstaunlicherweise zeigt die vorliegende Arbeit, dass das NOXA-Protein sowohl proteasomal als auch autophagosomal abgebaut werden kann. Die Markierung des NOXA-Proteins für den Abbau durch selektive Autophagie, könnte durch ein LC3-interagierende Region (LIR)-Motiv vermittelt werden, das in der Aminosäuresequenz des NOXA-Proteins identifiziert werden konnte. Interessanterweise potenziert die Kombination von Bortezomib mit bekannten Autophagie-Inhibitoren die Zelltod- sowie NOXA-Induktion, im Vergleich zu der Bortezomib Behandlung allein. Zudem ergab ein Substanzscreening zur Identifikation einer hocheffizienten dualen Blockade des proteasomalen und autophagosomalen Abbaus, dass der Fettsäure-Synthase-Inhibitor Orlistat für die Autophagie-Inhibition umfunktioniert werden kann. Infolgedessen führte die Kombinationsbehandlung mit Bortezomib und Orlistat zu einer sehr effizienten NOXA-Proteininduktion und einem Caspase-abhängigen Zelltod in MCL-Zellen. Dieser Zelltod ist ebenso abhängig von der anormal hohen Cyclin-D1/CDK4-Aktivität. Die Expressionsraten bestimmter anderer apoptotischer Proteine werden jedoch durch die Kombinationsbehandlung nicht beeinflusst. Zusammenfassend konnte in der vorliegenden Arbeit die Regulation der autophagosomalen Aktivität als neue Funktion der Cyclin D1/CDK4-Aktivität im MCL identifiziert werden. Diese Ergebnisse sind für die Behandlung von MCL-Patienten von großem Interesse, da die Kombination von Proteasominhibitoren mit Autophagie-Inhibitoren die Therapie deutlich verbessern, sowie Bortezomib-Resistenzen überwinden könnte. Außerdem besteht die Möglichkeit, dass diese Behandlungsoptionen, zusätzlich zu den bekannten Autophagie-Inhibitoren, auch konventionelle Medikamente beinhalten die hierbei als Regulatoren der autophagosomalen Abbaumechanismen eine neue Verwendung finden. Wiederum besteht das Risiko von antagonistischen Effekten bei der Kombination von Proteasominhibitoren mit Chemotherapeutika, da diese die Aktivität von Cyclin D1/CDK4 beeinträchtigen oder Autophagie induzieren könnten

A Global Plate Model Including Lithospheric Deformation Along Major Rifts and Orogens Since the Triassic

Global deep‐time plate motion models have traditionally followed a classical rigid plate approach, even though plate deformation is known to be significant. Here we present a global Mesozoic–Cenozoic deforming plate motion model that captures the progressive extension of all continental margins since the initiation of rifting within Pangea at ~240 Ma. The model also includes major failed continental rifts and compressional deformation along collision zones. The outlines and timing of regional deformation episodes are reconstructed from a wealth of published regional tectonic models and associated geological and geophysical data. We reconstruct absolute plate motions in a mantle reference frame with a joint global inversion using hot spot tracks for the last 80 million years and minimizing global trench migration velocities and net lithospheric rotation. In our optimized model, net rotation is consistently below 0.2°/Myr, and trench migration scatter is substantially reduced. Distributed plate deformation reaches a Mesozoic peak of 30 × 106 km2 in the Late Jurassic (~160–155 Ma), driven by a vast network of rift systems. After a mid‐Cretaceous drop in deformation, it reaches a high of 48 x 106 km2 in the Late Eocene (~35 Ma), driven by the progressive growth of plate collisions and the formation of new rift systems. About a third of the continental crustal area has been deformed since 240 Ma, partitioned roughly into 65% extension and 35% compression. This community plate model provides a framework for building detailed regional deforming plate networks and form a constraint for models of basin evolution and the plate‐mantle system

Universitäres Alumni-Management in Online Social Networks

Online Social Networks (OSN) bieten eine ausgezeichnete Möglichkeit für Hochschulen, ihre ehemaligen Studierenden zu vernetzen. Ziel dieses Artikels ist es, den State of the Art der Nutzung von OSN für die Alumni Arbeit zu beschreiben. Hierzu haben wir mit einer dreistufigen Suchstrategie für insgesamt 109 deutsche Universitäten deren Präsenzen für Alumni Gemeinschaften identifiziert, ausgewertet und miteinander verglichen. Die Ergebnisse verdeutlichen große Unterschiede. Nur wenige Universitäten verzichten auf die Nutzung eines OSN für die Alumni Arbeit, in der Regel nutzen sie mehrere. Die auf geschäftliche Ziele ausgerichteten Netze Xing und LinkedIn werden bevorzugt. Anhand der Indikatoren Reichweite, Aktivität und Resonanz haben wir Ranglisten erstellt, die zeigen, welche Universitäten sich in der Spitzengruppe befinden und welche noch Nachholbedarf haben

Topographic asymmetry of the South Atlantic from global models of mantle flow and lithospheric stretching

The relief of the South Atlantic is characterized by elevated passive continental margins along southern Africa and eastern Brazil, and by the bathymetric asymmetry of the southern oceanic basin where the western flank is much deeper than the eastern flank. We investigate the origin of these topographic features in the present and over time since the Jurassic with a model of global mantle flow and lithospheric deformation. The model progressively assimilates plate kinematics, plate boundaries and lithospheric age derived from global tectonic reconstructions with deforming plates, and predicts the evolution of mantle temperature, continental crustal thickness, long-wavelength dynamic topography, and isostatic topography. Mantle viscosity and the kinematics of the opening of the South Atlantic are adjustable parameters in thirteen model cases. Model predictions are compared to observables both for the present-day and in the past. Present-day predictions are compared to topography, mantle tomography, and an estimate of residual topography. Predictions for the past are compared to tectonic subsidence from backstripped borehole data along the South American passive margin, and to dynamic uplift as constrained by thermochronology in southern Africa. Comparison between model predictions and observations suggests that the first-order features of the topography of the South Atlantic are due to long-wavelength dynamic topography, rather than to asthenospheric processes. The uplift of southern Africa is best reproduced with a lower mantle that is at least 40 times more viscous than the upper mantle

Pharmacokinetically-guided dosing to improve the efficacy of brigatinib in non-small cell lung cancer patients

Brigatinib was recently approved for the treatment of anaplastic lymphoma kinase-positive non-small cell lung cancer and is dosed according to a one-dose-fits-all paradigm. We aimed to identify a pharmacokinetically-guided precision dosing strategy to improve treatment response with brigatinib through simulations using a previously published pharmacokinetic-pharmacodynamic model. Dosing strategies explored were the approved 180 mg QD; the highest tolerable dose tested in clinical trials: 240 mg QD; and two precision dosing strategies targeting the median trough concentrations following 180 mg QD, and 240 mg QD. We investigated the impact of alternative dosing regimens on progression-free survival (PFS), overall survival (OS) and the probability of developing a grade ≥2 rash or grade ≥2 amylase increase. Median PFS and OS increased by 1.6 and 7.8 months, respectively between the currently approved dosing strategy and precision dosing to the median trough concentration of the 240 mg dosing strategy, with only a minor increase in the probability of developing toxicity

Dewar Benzenoids Discovered in Carbon Nanobelts

© 2020 American Chemical Society. The synthesis of cyclacene nanobelts remains an elusive goal dating back over 60 years. These molecules represent the last unsynthesized building block of carbon nanotubes and may be useful both as seed molecules for the preparation of structurally well-defined carbon nanotubes and for understanding the behavior and formation of zigzag nanotubes more broadly. Here we report the discovery that isomers containing two Dewar benzenoid rings are the preferred form for several sizes of cyclacene. The predicted lower polyradical character and higher singlet-triplet stability that these isomers possess compared with their pure benzenoid counterparts suggest that they may be more stable synthetic targets than the structures that have previously been identified. Our findings should facilitate the exploration of new routes to cyclacene synthesis through Dewar benzene chemistry

Global patterns in Earth's dynamic topography since the Jurassic: the role of subducted slabs

We evaluate the spatial and temporal evolution of Earth's long-wavelength surface dynamic topography since the Jurassic using a series of high-resolution global mantle convection models. These models are Earth-like in terms of convective vigour, thermal structure, surface heat-flux and the geographic distribution of heterogeneity. The models generate a degree-2-dominated spectrum of dynamic topography with negative amplitudes above subducted slabs (i.e. circum-Pacific regions and southern Eurasia) and positive amplitudes elsewhere (i.e. Africa, north-western Eurasia and the central Pacific). Model predictions are compared with published observations and subsidence patterns from well data, both globally and for the Australian and southern African regions. We find that our models reproduce the long-wavelength component of these observations, although observed smaller-scale variations are not reproduced. We subsequently define geodynamic rules for how different surface tectonic settings are affected by mantle processes: (i) locations in the vicinity of a subduction zone show large negative dynamic topography amplitudes; (ii) regions far away from convergent margins feature long-term positive dynamic topography; and (iii) rapid variations in dynamic support occur along the margins of overriding plates (e.g. the western US) and at points located on a plate that rapidly approaches a subduction zone (e.g. India and the Arabia Peninsula). Our models provide a predictive quantitative framework linking mantle convection with plate tectonics and sedimentary basin evolution, thus improving our understanding of how subduction and mantle convection affect the spatio-temporal evolution of basin architecture.This research was supported by resources provided by the Pawsey Supercomputing Centre with funding from the Australian Government and the Government of Western Australia and with the assistance of resources from the National Computational Infrastructure (NCI), which is supported by the Australian Government. Sascha Brune was funded by the Marie Curie International Outgoing Fellowship 326115 and the Helmholtz Young Investigators Group CRYSTALS. Christian Heine was supported by ARC Linkage Project LP0989312 with Shell E & P and TOTAL. D. Rhodri Davies is funded by an ARC Future Fellowship (FT140101262) and Simon Williams and R. Dietmar Müller are supported by ARC grants DP130101946 and IH13020001

Epidemiology and Characteristics of Gastric Carcinoma in Childhood : An Analysis of Data from Population-Based and Clinical Cancer Registries

(1) Background: Gastric carcinoma is an exceptionally rare tumor in childhood. Little is known about the etiology, epidemiology, and clinical features of pediatric gastric carcinomas. This analysis aimed to fill this gap by increasing knowledge about the occurrence of gastric carcinoma in childhood. (2) Material and methods: Data from gastric carcinoma cases diagnosed between 2000 and 2017/2018 were retrieved from the Surveillance, Epidemiology, and End Results Program (SEER) and the German Center for Cancer Registry Data. Data from patients <20 years of age were analyzed for patient- and tumor-related characteristics. In addition, clinical data from patients with gastric carcinoma registered in the German Registry for Rare Pediatric Tumors (STEP) were analyzed for diagnostics, therapy, and outcome. (3) Results: Ninety-one cases of gastric carcinoma, mainly in adolescents, were identified in the epidemiologic cancer registries. Among patients with recorded staging data, advanced tumor stages were common (66.7%). Within the follow-up period covered, 63.7% of patients with clinical follow-up data died. Eight pediatric patients with gastric carcinoma were enrolled in the STEP registry, among whom two were patients with hereditary CDH1 mutations and another was a patient with Peutz–Jeghers syndrome. Three patients were found to have distinctly decreased immunoglobulin concentrations. All four patients in whom complete resection was achieved remained in remission. Three of the other four patients died despite multimodal therapy. (4) Conclusions: A combination of Helicobacter pylori infection and tumor predisposition and/or immunodeficiency appears to promote the development of gastric carcinoma in childhood. While patients with localized disease stages have a good chance of achieving durable remission through complete resection, patients with stage IV carcinomas face a dismal prognosis, highlighting the need to develop new strategies such as mutation-guided treatments