FOXM1 and CKS1 - novel cellular targets of the HPV oncogenes

Persistent infections with oncogenic types of human papillomaviruses (HPVs) cause cervical and other anogenital carcinomas as well as cancers of the head and neck regions and thereby contribute significantly to the global cancer burden. Despite the existence of efficient prophylactic vaccines, the worldwide number of HPV-related cancer cases is estimated to rise. It therefore remains an important task to further investigate and delineate the molecular mechanisms that underlie HPV-driven tumorigenesis, in specific the actions of the two viral oncogenes E6 and E7 which promote and sustain the malignant phenotype of HPV-positive cancers. This is also hoped to offer new opportunities for HPV-targeted therapeutic intervention. In the present study, the two host cell genes FOXM1 and CKS1B were identified as novel target genes of HPV E6 and E7. Interestingly, both FOXM1 and CKS1 have been described to possess oncogenic properties in different types of cancers. By stimulating their transcriptional promoters, E6 and E7 increased FOXM1 and CKS1 mRNA and protein levels in HPV-positive cells. The inhibition of the tumor suppressor p53 and the pocket protein family by E6 and E7, respectively, was determined to mediate the activation of FOXM1 and CKS1B. Hence, the disruption of the repressive DREAM complex by E6/E7 emerged as a likely mechanism involved in conveying HPV oncogene-induced promoter activation of FOXM1 and CKS1B. On the phenotypic level, the elevated level of CKS1 exerts pro-proliferative and senescence-suppressing effects in HPV-positive cancer cells. Furthermore, while not affecting proliferation per se, FOXM1 was shown to protect cervical cancer cells from the proliferation-suppressing effects of chemotherapy. In growth-arrested HPV-positive cells, neither FOXM1 nor CKS1 levels were found to decline, which would be in line with their activation by E6/E7 via DREAM disruption. Collectively, the results presented in this thesis contribute to a deeper understanding of HPV-driven carcinogenesis and decipher how the viral oncogenes E6 and E7 promote tumorigenesis through extensive modulation of the host cell’s molecular networks. They also provide evidence that interfering with FOXM1 or CKS1 expression or function could be an attractive future strategy for the therapy of HPV-induced cancers

Optical determination of the width of the band-tail states, and the excited and ground state energies of the principal dosimetric trap in feldspar

SR performed the measurements during her M.Sc., which was financially supported by the Deutschlandstipendium of the Bundesministerium für Bildung und Forschung – Stiftung Studium und Lehre (Ministry for Education and Research of the German government). The paper was written, during SR's PhD, which is financed by an AberDoc PhD Scholarship of Aberystwyth University. An Erasmus + student mobilitygrant enabled SR's research stay at the Center for Nuclear Technologies, Technical University of Denmark, DTU Risø Campus, Roskilde, Denmark. GEK acknowledges support from SNSF grant number PZ00P2_167960. Samples HAM-5 and JSH1-13 were taken in the framework of the QuakeRecNankai project, funded by the Belgian Science Policy Office (BELSPO BRAIN-be BR/121/A2). We thank Benny Guralnik for the provision of KTB-383-C, Renske Lambert for MBT-I-2430 and MBT-F-5704, Javier Garcia-Guinea for Cleavelandite and David Sanderson for F1.We constrain parameters that determine thermal stability of the infrared stimulated luminescence (IRSL) signal in a suite of 13 compositionally different feldspar samples by optical probing. We focus specifically on the excited and ground state of the principal trap and the width of the sub-conduction band-tail states. Excitation spectra measured at room temperature result in approximate trap depth of about 2.04 eV and the excited state energy at 1.44 ± 0.02 eV, irrespective of feldspar composition for the sample's measured here. Fitting the non-resonant rising continuum of the excitation spectra suggests that the width of the band-tail states accessible from the ground state of the trap (ΔE) ranges from 0.21 to 0.47 eV at room temperature between the different samples. Photoluminescence measurements are used to constrain the full sub-conduction band-tail width (Urbach width, Eu) using the excitation-energy-dependent emission (EDE), resulting in values ranging from 0.26 to 0.81 eV. While the depth of the principal trap and its main excited state seem to be independent of feldspar composition, the difference between ΔE and Eu seems to be related to sample K-content.PostprintPeer reviewe

Effects of microstructure on electrode performance

Li-ion batteries are widely used in consumer electronics due to their high energy density and currently gain further importance with regards to future mobility and their application in electric vehicles. In order to reduce production cost and thereby establish a competitive battery production, a further optimization of the cell components is required. Since extensive testing is time-consuming and expensive, predictive simulation tools are needed that are able to evaluate the electrode performance based on a given electrode structure. In this contribution, we will present 3D microstructure-resolved electrochemical continuum simulations conducted in the simulation framework BEST that is based on a thermodynamically consistent transport theory for mass and charge in the electrolyte and the active material [1]. Due to the finite volume implementation of the governing equations, real tomographic data of the electrode structure is used as the simulation domain. Previous studies have shown the importance of microstructural simulations with regards to the battery operation [2,3] and contributed to a deeper insight into the measured electrode behavior [4]. In our work we analyze NMC/Graphite cells to reveal the influence of their geometrical, structural and chemical properties. This information is combined to develop a digital twin of the cell containing relevant information about the morphology, composition and tortuosity. As starting point for our analysis, the simulation domain is generated based on 3D-reconstructions of electrode samples generated by imaging techniques such as micro-computed tomography (µCT) or focused ion beam - scanning electron microscopy (FIB-SEM) and additional information of complimentary analytical characterization techniques will be included in future work. The electrochemical simulation results are then compared to experimental data in order to identify and isolate important design parameters. The developed method acts as a tool to gain a deeper understanding of the underlying electrochemical processes in the cell and reveals structure-performance correlations for future battery optimization. [1] A. Latz and J. Zausch, “Thermodynamic consistent transport theory of Li-ion batteries”, J. Power Sources, 196, 3296-3302 (2011). [2] S. Hein et al.,“Influence of Conductive Additives and Binder on the Impedance of Lithium-Ion Battery Electrodes: Effect of Morphology”, J. Electrochem. Soc., 167, 013546 (2020). [3] T. Danner et al., “Thick electrodes for Li-ion batteries: A model based analysis”, J. Power Sources, 334, 191–201 (2016). [4] C. Hogrefe et al., “Mechanistic Details of the Spontaneous Intercalation of Li Metal into Graphite Electrodes”, J. Electrochem. Soc., 167, 140546 (2020

Stereo Laryngoscopic Impact Site Prediction for Droplet-Based Stimulation of the Laryngeal Adductor Reflex

The laryngeal adductor reflex (LAR) is a vital reflex of the human larynx. LAR malfunctions may cause life-threatening aspiration events. An objective, noninvasive, and reproducible method for LAR assessment is still lacking. Stimulation of the larynx by droplet impact, termed Microdroplet Impulse Testing of the LAR (MIT-LAR), may remedy this situation. However, droplet instability and imprecise stimulus application thus far prevented MIT-LAR from gaining clinical relevance. We present a system comprising two alternative, custom-built stereo laryngoscopes, each offering a distinct set of properties, a droplet applicator module, and image/point cloud processing algorithms to enable a targeted, droplet-based LAR stimulation. Droplet impact site prediction (ISP) is achieved by droplet trajectory identification and spatial target reconstruction. The reconstruction and ISP accuracies were experimentally evaluated. Global spatial reconstruction errors at the glottal area of (0.3±0.3) mm and (0.4±0.3) mm and global ISP errors of (0.9±0.6) mm and (1.3±0.8) mm were found for a rod lens-based and an alternative, fiberoptic laryngoscope, respectively. In the case of the rod lens-based system, 96% of all observed ISP error values are inferior to 2 mm; a value of 80% was found with the fiberoptic assembly. This contribution represents an important step towards introducing a reproducible and objective LAR screening method into the clinical routine

Effects of microstructural features on the performance of a commercial Ni-rich NMC cathode

Li-ion batteries are widely used in consumer electronics due to their high energy density and currently gain further importance with regards to future mobility and their application in electric vehicles. In order to reduce production cost and thereby establish a competitive battery production, a further optimization of the cell components is required. Since extensive testing is time-consuming and expensive, predictive simulation tools are needed that are able to evaluate the electrode performance based on a given electrode structure. In this contribution, we will present 3D microstructure-resolved electrochemical continuum simulations conducted in the simulation framework BEST [1]. The governing equations are given by the mass and charge conservation in the active material and electrolyte. Discretization is done using a Finite Volume scheme which allows to directly use real tomographic data of the electrode microstructures as the simulation domain. Previous studies have shown the importance of microstructural simulations with regards to the battery operation [2,3] and contributed to a deeper insight into the observed electrode behavior [4]. In our work we analyze a commercial NMC811 cathode to reveal the influence of individual electrode features. The simulation domain is generated based on 3D-reconstructions of electrode samples generated by focused ion beam - scanning electron microscopy (FIB-SEM). The simulation results are then compared to experimental data in order to identify and isolate important design parameters. Here, the poor electronic conductivity of the electrode due to a low content of carbon-binder-domain (CBD) is identified to severely limit achievable cell capacity and increase the cell impedance. The developed method will also be used in order to identify critical microstructural parameters with regards to aging of NMC cathode materials in future work. [1] A. Latz and J. Zausch, “Thermodynamic consistent transport theory of Li-ion batteries”, J. Power Sources, 196, 3296-3302 (2011). [2] S. Hein et al.,“Influence of Conductive Additives and Binder on the Impedance of Lithium-Ion Battery Electrodes: Effect of Morphology”, J. Electrochem. Soc., 167, 013546 (2020). [3] T. Danner et al., “Thick electrodes for Li-ion batteries: A model based analysis”, J. Power Sources, 334, 191–201 (2016). [4] C. Hogrefe et al., “Mechanistic Details of the Spontaneous Intercalation of Li Metal into Graphite Electrodes”, J. Electrochem. Soc., 167, 140546 (2020

Repression of human papillomavirus oncogene expression under hypoxia is mediated by PI3K/mTORC2/AKT signaling

Oncogenic HPV types are major human carcinogens. Under hypoxia, HPV-positive cancer cells can repress the viral E6/E7 oncogenes and induce a reversible growth arrest. This response could contribute to therapy resistance, immune evasion, and tumor recurrence upon reoxygenation. Here, we uncover evidence that HPV oncogene repression is mediated by hypoxia-induced activation of canonical PI3K/mTORC2/AKT signaling. AKT-dependent downregulation of E6/E7 is only observed under hypoxia and occurs, at least in part, at the transcriptional level. Quantitative proteome analyses identify additional factors as candidates to be involved in AKT-dependent E6/E7 repression and/or hypoxic PI3K/mTORC2/AKT activation. These results connect PI3K/mTORC2/AKT signaling with HPV oncogene regulation, providing new mechanistic insights into the cross talk between oncogenic HPVs and their host cells.Hypoxia is linked to therapeutic resistance and poor clinical prognosis for many tumor entities, including human papillomavirus (HPV)-positive cancers. Notably, HPV-positive cancer cells can induce a dormant state under hypoxia, characterized by a reversible growth arrest and strong repression of viral E6/E7 oncogene expression, which could contribute to therapy resistance, immune evasion and tumor recurrence. The present work aimed to gain mechanistic insights into the pathway(s) underlying HPV oncogene repression under hypoxia. We show that E6/E7 downregulation is mediated by hypoxia-induced stimulation of AKT signaling. Ablating AKT function in hypoxic HPV-positive cancer cells by using chemical inhibitors efficiently counteracts E6/E7 repression. Isoform-specific activation or downregulation of AKT1 and AKT2 reveals that both AKT isoforms contribute to hypoxic E6/E7 repression and act in a functionally redundant manner. Hypoxic AKT activation and consecutive E6/E7 repression is dependent on the activities of the canonical upstream AKT regulators phosphoinositide 3-kinase (PI3K) and mechanistic target of rapamycin (mTOR) complex 2 (mTORC2). Hypoxic downregulation of E6/E7 occurs, at least in part, at the transcriptional level. Modulation of E6/E7 expression by the PI3K/mTORC2/AKT cascade is hypoxia specific and not observed in normoxic HPV-positive cancer cells. Quantitative proteome analyses identify additional factors as candidates to be involved in hypoxia-induced activation of the PI3K/mTORC2/AKT signaling cascade and in the AKT-dependent repression of the E6/E7 oncogenes under hypoxia. Collectively, these data uncover a functional key role of the PI3K/mTORC2/AKT signaling cascade for viral oncogene repression in hypoxic HPV-positive cancer cells and provide new insights into the poorly understood cross talk between oncogenic HPVs and their host cells under hypoxia

Quantum Imaging with Incoherently Scattered Light from a Free-Electron Laser

The advent of accelerator-driven free-electron lasers (FEL) has opened new avenues for high-resolution structure determination via diffraction methods that go far beyond conventional x-ray crystallography methods. These techniques rely on coherent scattering processes that require the maintenance of first-order coherence of the radiation field throughout the imaging procedure. Here we show that higher-order degrees of coherence, displayed in the intensity correlations of incoherently scattered x-rays from an FEL, can be used to image two-dimensional objects with a spatial resolution close to or even below the Abbe limit. This constitutes a new approach towards structure determination based on incoherent processes, including Compton scattering, fluorescence emission or wavefront distortions, generally considered detrimental for imaging applications. Our method is an extension of the landmark intensity correlation measurements of Hanbury Brown and Twiss to higher than second-order paving the way towards determination of structure and dynamics of matter in regimes where coherent imaging methods have intrinsic limitations

PEtab -- interoperable specification of parameter estimation problems in systems biology

Reproducibility and reusability of the results of data-based modeling studies are essential. Yet, there has been -- so far -- no broadly supported format for the specification of parameter estimation problems in systems biology. Here, we introduce PEtab, a format which facilitates the specification of parameter estimation problems using Systems Biology Markup Language (SBML) models and a set of tab-separated value files describing the observation model and experimental data as well as parameters to be estimated. We already implemented PEtab support into eight well-established model simulation and parameter estimation toolboxes with hundreds of users in total. We provide a Python library for validation and modification of a PEtab problem and currently 20 example parameter estimation problems based on recent studies. Specifications of PEtab, the PEtab Python library, as well as links to examples, and all supporting software tools are available at https://github.com/PEtab-dev/PEtab, a snapshot is available at https://doi.org/10.5281/zenodo.3732958. All original content is available under permissive licenses

The ubiquitin ligase CHIP integrates proteostasis and aging by regulation of insulin receptor turnover

Aging is attended by a progressive decline in protein homeostasis (proteostasis), aggravating the risk for protein aggregation diseases. To understand the coordination between proteome imbalance and longevity, we addressed the mechanistic role of the quality-control ubiquitin ligase CHIP, which is a key regulator of proteostasis. We observed that CHIP deficiency leads to increased levels of the insulin receptor (INSR) and reduced lifespan of worms and flies. The membrane-bound INSR regulates the insulin and IGF1 signaling (IIS) pathway and thereby defines metabolism and aging. INSR is a direct target of CHIP, which triggers receptor monoubiquitylation and endocytic-lysosomal turnover to promote longevity. However, upon proteotoxic stress conditions and during aging, CHIP is recruited toward disposal of misfolded proteins, reducing its capacity to degrade the INSR. Our study indicates a competitive relationship between proteostasis and longevity regulation through CHIP-assisted proteolysis, providing a mechanistic concept for understanding the impact of proteome imbalance on aging

Genetic Variants For Head Size Share Genes and Pathways With Cancer

The size of the human head is highly heritable, but genetic drivers of its variation within the general population remain unmapped. We perform a genome-wide association study on head size (N = 80,890) and identify 67 genetic loci, of which 50 are novel. Neuroimaging studies show that 17 variants affect specific brain areas, but most have widespread effects. Gene set enrichment is observed for various cancers and the p53, Wnt, and ErbB signaling pathways. Genes harboring lead variants are enriched for macrocephaly syndrome genes (37-fold) and high-fidelity cancer genes (9-fold), which is not seen for human height variants. Head size variants are also near genes preferentially expressed in intermediate progenitor cells, neural cells linked to evolutionary brain expansion. Our results indicate that genes regulating early brain and cranial growth incline to neoplasia later in life, irrespective of height. This warrants investigation of clinical implications of the link between head size and cancer