TOPK modulates tumour-specific radiosensitivity and correlates with recurrence after prostate radiotherapy.

BACKGROUND: Tumour-specific radiosensitising treatments may enhance the efficacy of radiotherapy without exacerbating side effects. In this study we determined the radiation response following depletion or inhibition of TOPK, a mitogen-activated protein kinase kinase family Ser/Thr protein kinase that is upregulated in many cancers. METHODS: Radiation response was studied in a wide range of cancer cell lines and normal cells using colony formation assays. The effect on cell cycle progression was assessed and the relationship between TOPK expression and therapeutic efficacy was studied in a cohort of 128 prostate cancer patients treated with radical radiotherapy. RESULTS: TOPK knockdown did not alter radiation response in normal tissues, but significantly enhanced radiosensitivity in cancer cells. This result was recapitulated in TOPK knockout cells and with the TOPK inhibitor, OTS964. TOPK depletion altered the G1/S transition and G2/M arrest in response to radiation. Furthermore, TOPK depletion increased chromosomal aberrations, multinucleation and apoptotic cell death after irradiation. These results suggest a possible role for TOPK in the radiation-induced DNA damage checkpoints. These findings have clinical relevance, as elevated TOPK protein expression was associated with poorer clinical outcomes in prostate cancer patients treated with radical radiotherapy. CONCLUSIONS: This study demonstrates that TOPK disruption may cause tumour-specific radiosensitisation in multiple different tumour types.

Holliday junction-containing DNA structures persist in cells lacking Sgs1 or Top3 following exposure to DNA damage.

The Sgs1-Rmi1-Top3 "dissolvasome" is required for the maintenance of genome stability and has been implicated in the processing of various types of DNA structures arising during DNA replication. Previous investigations have revealed that unprocessed (X-shaped) homologous recombination repair (HRR) intermediates persist when S-phase is perturbed by using methyl methanesulfonate (MMS) in Saccharomyces cerevisiae cells with impaired Sgs1 or Top3. However, the precise nature of these persistent DNA structures remains poorly characterized. Here, we report that ectopic expression of either of two heterologous and structurally unrelated Holliday junction (HJ) resolvases, Escherichia coli RusA or human GEN1(1-527), promotes the removal of these X-structures in vivo. Moreover, other types of DNA replication intermediates, including stalled replication forks and non-HRR-dependent X-structures, are refractory to RusA or GEN1(1-527), demonstrating specificity of these HJ resolvases for MMS-induced X-structures in vivo. These data suggest that the X-structures persisting in cells with impaired Sgs1 or Top3 contain HJs. Furthermore, we demonstrate that Sgs1 directly promotes X-structure removal, because the persistent structures arising in Sgs1-deficient strains are eliminated when Sgs1 is reactivated in vivo. We propose that HJ resolvases and Sgs1-Top3-Rmi1 comprise two independent processes to deal with HJ-containing DNA intermediates arising during HRR in S-phase.

Synthesis of cerium, zirconium, and copper doped zinc oxide nanoparticles as potential biomaterials for tissue engineering applications.

A novel eco-friendly high throughput continuous hydrothermal flow system was used to synthesise phase pure ZnO and doped ZnO in order to explore their properties for tissue engineering applications. Cerium, zirconium, and copper were introduced as dopants during flow synthesis of ZnO nanoparticles, Zirconium doped ZnO were successfully synthesised, however secondary phases of CeO and CuO were detected in X-ray diffraction (XRD). The nanoparticles were characterised using X-ray diffraction, Brunauer-Emmett-Teller (BET), Dynamic Light scattering Measurements, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and RAMAN spectroscopy was used to evaluate physical, chemical, and structural properties. The change in BET surface area was also significant, the surface area increased from 11.35 (ZnO_2) to 26.18 (ZrZnO_5). However. In case of CeZnO_5 and CuZnO_5 was not significant 13.68 (CeZnO_5) and 12.16 (CuZnO_5) respectively. Cell metabolic activity analysis using osteoblast-like cells (MG63) and human embryonic derived mesenchymal stem cells (hES-MP) demonstrated that doped ZnO nanoparticles supported higher cell metabolic activity compared to cells grown in standard media with no nanoparticles added, or pure zinc oxide nanoparticles. The ZrZnO_5 demonstrated the highest cell metabolic activity and non-cytotoxicity over the duration of 28 days as compared to un doped or Ce or Cu incorporated nanoparticles. The current data suggests that Zirconium doping positively enhances the properties of ZnO nanoparticles by increasing the surface area and cell proliferation. Therefore, are potential additives within biomaterials or for tissue engineering applications.

Global fine-resolution data on springtail abundance and community structure.

Springtails (Collembola) inhabit soils from the Arctic to the Antarctic and comprise an estimated ~32% of all terrestrial arthropods on Earth. Here, we present a global, spatially-explicit database on springtail communities that includes 249,912 occurrences from 44,999 samples and 2,990 sites. These data are mainly raw sample-level records at the species level collected predominantly from private archives of the authors that were quality-controlled and taxonomically-standardised. Despite covering all continents, most of the sample-level data come from the European continent (82.5% of all samples) and represent four habitats: woodlands (57.4%), grasslands (14.0%), agrosystems (13.7%) and scrublands (9.0%). We included sampling by soil layers, and across seasons and years, representing temporal and spatial within-site variation in springtail communities. We also provided data use and sharing guidelines and R code to facilitate the use of the database by other researchers. This data paper describes a static version of the database at the publication date, but the database will be further expanded to include underrepresented regions and linked with trait data.

Cycling Rate-Induced Spatially-Resolved Heterogeneities in Commercial Cylindrical Li-Ion Batteries.

Synchrotron high-energy X-ray diffraction computed tomography has been employed to investigate, for the first time, commercial cylindrical Li-ion batteries electrochemically cycled over the two cycling rates of C/2 and C/20. This technique yields maps of the crystalline components and chemical species as a cross-section of the cell with high spatiotemporal resolution (550 × 550 images with 20 × 20 × 3 µm3 voxel size in ca. 1 h). The recently developed Direct Least-Squares Reconstruction algorithm is used to overcome the well-known parallax problem and led to accurate lattice parameter maps for the device cathode. Chemical heterogeneities are revealed at both electrodes and are attributed to uneven Li and current distributions in the cells. It is shown that this technique has the potential to become an invaluable diagnostic tool for real-world commercial batteries and for their characterization under operating conditions, leading to unique insights into "real" battery degradation mechanisms as they occur.

High Throughput Synthesis and Screening of Oxygen Reduction Catalysts in the MTiO3 (M = Ca, Sr, Ba) Perovskite Phase Diagram.

A library of 66 perovskite BaxSryCazTiO3 (x + y + z = 1) samples (ca. three grams per sample) was made in ca. 14 h using a high-throughput continuous hydrothermal flow synthesis system. The as-synthesized samples were collected from the outlet of the process and then cleaned and freeze-dried before being evaluated individually as oxygen reduction catalysts using a rotating disk electrode testing technique. To establish any correlations between physical and electrochemical characterization data, the as-synthesized samples were investigated using analytical methods including BET surface area, powder X-ray diffraction (PXRD) and in selected cases, transmission electron microscopy (TEM). The aforementioned approach was validated as being able to quickly identify oxygen reduction catalysts from new libraries of electrocatalysts.

Enhancing bifunctional catalytic activity of cobalt-nickel sulfide spinel nanocatalysts through transition metal doping and its application in secondary zinc-air batteries.

Developing large-scale and high-performance OER (oxygen evolution reaction) and ORR (oxygen reduction reaction) catalysts have been a challenge for commercializing secondary zinc-air batteries. In this work, transition metal-doped cobalt-nickel sulfide spinels are directly produced via a continuous hydrothermal flow synthesis (CHFS) approach. The nanosized cobalt-nickel sulfides are doped with Ag, Fe, Mn, Cr, V, and Ti and evaluated as bifunctional OER and ORR catalyst for Zn-air battery application. Among the doped spinel catalysts, Mn-doped cobalt-nickel sulfides (Ni1.29Co1.49Mn0.22S4) exhibit the most promising OER and ORR performance, showing an ORR onset potential of 0.9 V vs. RHE and an OER overpotential of 348 mV measured at 10 mA cm-2, which is attributed to their high surface area, electronic structure of the dopant species, and the synergistic coupling of the dopant species with the active host cations. The dopant ions primarily alter the host cation composition, with the Mn(iii) cation linked to the introduction of active sites by its favourable electronic structure. A power density of 75 mW cm-2 is achieved at a current density of 140 mA cm-2 for the zinc-air battery using the manganese-doped catalyst, a 12% improvement over the undoped cobalt-nickel sulfide and superior to that of the battery with a commercial RuO2 catalyst.

The anti-malarial drug atovaquone potentiates platinum-mediated cancer cell death by increasing oxidative stress.

Platinum chemotherapies are highly effective cytotoxic agents but often induce resistance when used as monotherapies. Combinatorial strategies limit this risk and provide effective treatment options for many cancers. Here, we repurpose atovaquone (ATQ), a well-tolerated & FDA-approved anti-malarial agent by demonstrating that it potentiates cancer cell death of a subset of platinums. We show that ATQ in combination with carboplatin or cisplatin induces striking and repeatable concentration- and time-dependent cell death sensitization in vitro across a variety of cancer cell lines. ATQ induces mitochondrial reactive oxygen species (mROS), depleting intracellular glutathione (GSH) pools in a concentration-dependent manner. The superoxide dismutase mimetic MnTBAP rescues ATQ-induced mROS production and pre-loading cells with the GSH prodrug N-acetyl cysteine (NAC) abrogates the sensitization. Together, these findings implicate ATQ-induced oxidative stress as key mediator of the sensitizing effect. At physiologically achievable concentrations, ATQ and carboplatin furthermore synergistically delay the growth of three-dimensional avascular spheroids. Clinically, ATQ is a safe and specific inhibitor of the electron transport chain (ETC) and is concurrently being repurposed as a candidate tumor hypoxia modifier. Together, these findings suggest that ATQ is deserving of further study as a candidate platinum sensitizing agent.

The structural variation landscape in 492 Atlantic salmon genomes.

Structural variants (SVs) are a major source of genetic and phenotypic variation, but remain challenging to accurately type and are hence poorly characterized in most species. We present an approach for reliable SV discovery in non-model species using whole genome sequencing and report 15,483 high-confidence SVs in 492 Atlantic salmon (Salmo salar L.) sampled from a broad phylogeographic distribution. These SVs recover population genetic structure with high resolution, include an active DNA transposon, widely affect functional features, and overlap more duplicated genes retained from an ancestral salmonid autotetraploidization event than expected. Changes in SV allele frequency between wild and farmed fish indicate polygenic selection on behavioural traits during domestication, targeting brain-expressed synaptic networks linked to neurological disorders in humans. This study offers novel insights into the role of SVs in genome evolution and the genetic architecture of domestication traits, along with resources supporting reliable SV discovery in non-model species.

Demonstration of the Use of Environmental DNA for the Non-Invasive Genotyping of a Bivalve Mollusk, the European Flat Oyster (Ostrea edulis).

Accurate SNP (single nucleotide polymorphism) genotype information is critical for a wide range of selective breeding applications in aquaculture, including parentage assignment, marker-assisted, and genomic selection. However, the sampling of tissue for genetic analysis can be invasive for juvenile animals or taxa where sampling tissue is difficult or may cause mortality (e.g. bivalve mollusks). Here, we demonstrate a novel, non-invasive technique for sampling DNA based on the collection of environmental DNA using European Flat Oysters (Ostrea edulis) as an example. The live animals are placed in individual containers until sufficient genetic material is released into the seawater which is then recovered by filtration. We compared the results of tissue and eDNA derived SNP genotype calls using a PCR based genotyping platform. We found that 100% accurate genotype calls from eDNA are possible, but depend on appropriate filtration and the dilution of the sample throughout the workflow. We also developed an additional low-cost DNA extraction technique which provided >99% correct SNP genotype calls in comparison to tissue. It was concluded that eDNA sampling can be used in hatchery and selective breeding programs applicable to any aquatic organism for which direct tissue sampling may result in animal welfare concerns or mortality.

Tailoring the electrochemical activity of magnesium chromium oxide towards Mg batteries through control of size and crystal structure.

Chromium oxides with the spinel structure have been predicted to be promising high voltage cathode materials in magnesium batteries. Perennial challenges involving the mobility of Mg2+ and reaction kinetics can be circumvented by nano-sizing the materials in order to reduce diffusion distances, and by using elevated temperatures to overcome activation energy barriers. Herein, ordered 7 nm crystals of spinel-type MgCr2O4 were synthesized by a conventional batch hydrothermal method. In comparison, the relatively underexplored Continuous Hydrothermal Flow Synthesis (CHFS) method was used to make highly defective sub-5 nm MgCr2O4 crystals. When these materials were made into electrodes, they were shown to possess markedly different electrochemical behavior in a Mg2+ ionic liquid electrolyte, at moderate temperature (110 °C). The anodic activity of the ordered nanocrystals was attributed to surface reactions, most likely involving the electrolyte. In contrast, evidence was gathered regarding the reversible bulk deintercalation of Mg2+ from the nanocrystals made by CHFS. This work highlights the impact on electrochemical behavior of a precise control of size and crystal structure of MgCr2O4. It advances the understanding and design of new cathode materials for Mg-based batteries.

T-LAK cell-originated protein kinase (TOPK): an emerging target for cancer-specific therapeutics.

'Targeted' or 'biological' cancer treatments rely on differential gene expression between normal tissue and cancer, and genetic changes that render tumour cells especially sensitive to the agent being applied. Problems exist with the application of many agents as a result of damage to local tissues, tumour evolution and treatment resistance, or through systemic toxicity. Hence, there is a therapeutic need to uncover specific clinical targets which enhance the efficacy of cancer treatment whilst minimising the risk to healthy tissues. T-LAK cell-originated protein kinase (TOPK) is a MAPKK-like kinase which plays a role in cell cycle regulation and mitotic progression. As a consequence, TOPK expression is minimal in differentiated cells, although its overexpression is a pathophysiological feature of many tumours. Hence, TOPK has garnered interest as a cancer-specific biomarker and biochemical target with the potential to enhance cancer therapy whilst causing minimal harm to normal tissues. Small molecule inhibitors of TOPK have produced encouraging results as a stand-alone treatment in vitro and in vivo, and are expected to advance into clinical trials in the near future. In this review, we present the current literature pertaining to TOPK as a potential clinical target and describe the progress made in uncovering its role in tumour development. Firstly, we describe the functional role of TOPK as a pro-oncogenic kinase, followed by a discussion of its potential as a target for the treatment of cancers with high-TOPK expression. Next, we provide an overview of the current preclinical progress in TOPK inhibitor discovery and development, with respect to future adaptation for clinical use.

Oxidative Phosphorylation as an Emerging Target in Cancer Therapy.

Cancer cells have upregulated glycolysis compared with normal cells, which has led many to the assumption that oxidative phosphorylation (OXPHOS) is downregulated in all cancers. However, recent studies have shown that OXPHOS can be also upregulated in certain cancers, including leukemias, lymphomas, pancreatic ductal adenocarcinoma, high OXPHOS subtype melanoma, and endometrial carcinoma, and that this can occur even in the face of active glycolysis. OXPHOS inhibitors could therefore be used to target cancer subtypes in which OXPHOS is upregulated and to alleviate therapeutically adverse tumor hypoxia. Several drugs including metformin, atovaquone, and arsenic trioxide are used clinically for non-oncologic indications, but emerging data demonstrate their potential use as OXPHOS inhibitors. We highlight novel applications of OXPHOS inhibitors with a suitable therapeutic index to target cancer cell metabolism. Clin Cancer Res; 24(11); 2482-90. ©2018 AACR.

Mechanistic insights of Li+ diffusion within doped LiFePO4 from Muon Spectroscopy.

The Li+ ion diffusion characteristics of V- and Nb-doped LiFePO4 were examined with respect to undoped LiFePO4 using muon spectroscopy (µSR) as a local probe. As little difference in diffusion coefficient between the pure and doped samples was observed, offering DLi values in the range 1.8-2.3 × 10-10 cm2 s-1, this implied the improvement in electrochemical performance observed within doped LiFePO4 was not a result of increased local Li+ diffusion. This unexpected observation was made possible with the µSR technique, which can measure Li+ self-diffusion within LiFePO4, and therefore negated the effect of the LiFePO4 two-phase delithiation mechanism, which has previously prevented accurate Li+ diffusion comparison between the doped and undoped materials. Therefore, the authors suggest that µSR is an excellent technique for analysing materials on a local scale to elucidate the effects of dopants on solid-state diffusion behaviour.

Prognostic significance of admission heart failure in patients with non-ST-elevation acute coronary syndromes (from the Canadian Acute Coronary Syndrome Registries).

We evaluated the in-hospital and 1-year outcomes and predictors of admission heart failure in patients with non-ST-elevation acute coronary syndromes (NSTE-ACSs) without previous heart failure. We analyzed 4,825 patients with NSTE-ACS without a history of congestive heart failure who were included in the multicenter Canadian ACS Registries. Patients in Killip's class II/III on admission (n = 559, 11.6%) were compared with patients in Killip's class I. Patients with heart failure on admission were older (72 [64, 79] vs 64 [54, 73] years, p < 0.0001), with higher baseline creatinine levels (96 vs 88 mmol/dl, p <0.0001), more diabetes (32.2% vs 22.8%, p < 0.0001), hypertension (58% vs 52.4%, p = 0.014), previous myocardial infarction (MI; 38.9% vs 30.3%, p < 0.0001), previous stroke (13.5% vs 7.4%, p < 0.0001), and had more ST depression on admission (27.7% vs 17.3%, p < 0.0001). In-hospital treatment was similar except for a lower rate of aspirin therapy and fewer coronary interventions. Crude event rates were significantly higher in patients with heart failure (in-hospital death 3.6% vs 1.1%, p < 0.0001; death or MI 7.9% vs 4.7%, p = 0.0011; stroke 1.1% vs 0.4%, p = 0.03). One-year event rates were also higher in patients with heart failure (death 14.6% vs 4.4%, p < 0.0001; MI 9.3% vs 6.6%, p = 0.03; death or MI 21.5% vs 10.3%, p < 0.0001). Variables independently associated with heart failure were age (odds ratio 1.57, 95% confidence interval 1.43 to 1.73), diabetes mellitus (odds ratio 1.53, 95% confidence interval 1.24 to 1.89), admission ST depression (odds ratio 1.52, 95% confidence interval 1.22 to 1.90), previous MI, and baseline creatinine. Heart failure on admission was an independent predictor of in-hospital death, death or MI, and stroke and of 1-year death and death or MI. In conclusion, in patients with NSTE-ACS, heart failure on admission is associated with increased short- and long-term rates of death and MI.

Longest follow-up of in situ working Bjork Shiley valve: 42-year follow-up.

The Bjork Shiley valve (BSV) is considered as the pioneer among modern disc valves, and eventually evolved into a reliable prosthesis after considerable research and multiple modifications. Various case reports have been published with follow-up of different types of BSV. We are reporting the longest follow-up ever published of a plano-convex type of BSV. Our patient's valve was implanted in 1973 due to a congenital bicuspid aortic valve with concomitant severe, symptomatic aortic stenosis, discovered at the age of 27. She presented with exertional dyspnoea, syncope and chest pain; however, her cardiovascular status remained stable and these symptoms abated after successful valve replacement at the age of 34. She is now 77 years old with no limitations in her activities and is able to walk a few miles most days of the week. Her echocardiograms throughout the decades have shown acceptable gradients across the aortic prosthesis without evidence of haemolysis. Our case report includes a summary of the patient with a discussion of the evidence that supports the durability of the original plano-convex BSV.

The anti-malarial atovaquone increases radiosensitivity by alleviating tumour hypoxia.

Tumour hypoxia renders cancer cells resistant to cancer therapy, resulting in markedly worse clinical outcomes. To find clinical candidate compounds that reduce hypoxia in tumours, we conduct a high-throughput screen for oxygen consumption rate (OCR) reduction and identify a number of drugs with this property. For this study we focus on the anti-malarial, atovaquone. Atovaquone rapidly decreases the OCR by more than 80% in a wide range of cancer cell lines at pharmacological concentrations. In addition, atovaquone eradicates hypoxia in FaDu, HCT116 and H1299 spheroids. Similarly, it reduces hypoxia in FaDu and HCT116 xenografts in nude mice, and causes a significant tumour growth delay when combined with radiation. Atovaquone is a ubiquinone analogue, and decreases the OCR by inhibiting mitochondrial complex III. We are now undertaking clinical studies to assess whether atovaquone reduces tumour hypoxia in patients, thereby increasing the efficacy of radiotherapy.

Microwave-assisted synthesis and electrochemical evaluation of VO2 (B) nanostructures.

Understanding how intercalation materials change during electrochemical operation is paramount to optimizing their behaviour and function and in situ characterization methods allow us to observe these changes without sample destruction. Here we first report the improved intercalation properties of bronze phase vanadium dioxide VO2 (B) prepared by a microwave-assisted route which exhibits a larger electrochemical capacity (232 mAh g(-1)) compared with VO2 (B) prepared by a solvothermal route (197 mAh g(-1)). These electrochemical differences have also been followed using in situ X-ray absorption spectroscopy allowing us to follow oxidation state changes as they occur during battery operation.

Regulation of O2 consumption by the PI3K and mTOR pathways contributes to tumor hypoxia.

BACKGROUND: Inhibitors of the phosphatidylinositol 3-kinase (PI3K) and the mammalian target of rapamycin (mTOR) pathway are currently in clinical trials. In addition to antiproliferative and proapoptotic effects, these agents also diminish tumor hypoxia. Since hypoxia is a major cause of resistance to radiotherapy, we sought to understand how it is regulated by PI3K/mTOR inhibition. METHODS: Whole cell, mitochondrial, coupled and uncoupled oxygen consumption were measured in cancer cells after inhibition of PI3K (Class I) and mTOR by pharmacological means or by RNAi. Mitochondrial composition was assessed by immunoblotting. Hypoxia was measured in spheroids, in tumor xenografts and predicted with mathematical modeling. RESULTS: Inhibition of PI3K and mTOR reduced oxygen consumption by cancer cell lines is predominantly due to reduction of mitochondrial respiration coupled to ATP production. Hypoxia in tumor spheroids was reduced, but returned after removal of the drug. Murine tumors had increased oxygenation even in the absence of average perfusion changes or tumor necrosis. CONCLUSIONS: Targeting the PI3K/mTOR pathway substantially reduces mitochondrial oxygen consumption thereby reducing tumor hypoxia. These alterations in tumor hypoxia should be considered in the design of clinical trials using PI3K/mTOR inhibitors, particularly in conjunction with radiotherapy.

Pathways for Holliday junction processing during homologous recombination in Saccharomyces cerevisiae.

The Saccharomyces cerevisiae Rmi1 protein is a component of the highly conserved Sgs1-Top3-Rmi1 complex. Deletion of SGS1, TOP3, or RMI1 is synthetically lethal when combined with the loss of the Mus81-Mms4 or Slx1-Slx4 endonucleases, which have been implicated in Holliday junction (HJ) resolution. To investigate the causes of this synthetic lethality, we isolated a temperature-sensitive mutant of the RMI1 strain, referred to as the rmi1-1 mutant. At the restrictive temperature, this mutant phenocopies an rmi1Δ strain but behaves like the wild type at the permissive temperature. Following a transient exposure to methyl methanesulfonate, rmi1-1 mutants accumulate unprocessed homologous recombination repair (HRR) intermediates. These intermediates are slowly resolved at the restrictive temperature, revealing a redundant resolution activity when Rmi1 is impaired. This resolution depends on Mus81-Mms4 but not on either Slx1-Slx4 or another HJ resolvase, Yen1. Similar results were also observed when Top3 function was impaired. We propose that the Sgs1-Top3-Rmi1 complex constitutes the main pathway for the processing of HJ-containing HRR intermediates but that Mus81-Mms4 can also resolve these intermediates.