4,663 research outputs found
Upregulation of Id1 by Epstein-Barr Virus-encoded LMP1 confers resistance to TGFβ-mediated growth inhibition
BACKGROUND: Epstein-Barr virus (EBV)-encoded LMP1 protein is commonly expressed in nasopharyngeal carcinoma (NPC). LMP1 is a prime candidate for driving tumourigenesis given its ability to activate multiple signalling pathways and to alter the expression and activity of variety of downstream targets. Resistance to TGFβ-mediated cytostasis is one of the growth transforming effects of LMP1. Of the downstream targets manipulated by LMP1, the induction of Id1 and inactivation of Foxo3a appear particularly relevant to LMP1-mediated effects. Id1, a HLH protein is implicated in cell transformation and plays a role in cell proliferation, whilst Foxo3a, a transcription factor controls cell integrity and homeostasis by regulating apoptosis. The mechanism(s) by which LMP1 induces these effects have not been fully characterised. RESULTS: In this study, we demonstrate that the ability of LMP1 to induce the phosphorylation and inactivation of Foxo3a is linked to the upregulation of Id1. Furthermore, we show that the induction of Id1 is essential for the transforming function of LMP1 as over-expression of Id1 increases cell proliferation, attenuates TGFβ-SMAD-mediated transcription and renders cells refractory to TGFβ-mediated cytostasis. Id1 silencing in LMP1-expressing epithelial cells abolishes the inhibitory effect of LMP1 on TGFβ-mediated cell growth arrest and reduces the ability of LMP1 to attenuate SMAD transcriptional activity. In response to TGFβ stimulation, LMP1 does not abolish SMAD phosphorylation but inhibits p21 protein expression. In addition, we found the induction of Id1 in LMP1-expressing cells upon stimulation by TGFβ. We provide evidence that LMP1 suppresses the transcriptional repressor ATF3, possibly leading to the TGFβ-induced Id1 upregulation. CONCLUSION: The current data provide novel information regarding the mechanisms by which LMP1 suppresses TGFβ-induced cytostasis, highlighting the importance of Id1 in LMP1 mediated cell transformatio
Multi-Scale Attention-based Multiple Instance Learning for Classification of Multi-Gigapixel Histology Images
Histology images with multi-gigapixel of resolution yield rich information
for cancer diagnosis and prognosis. Most of the time, only slide-level label is
available because pixel-wise annotation is labour intensive task. In this
paper, we propose a deep learning pipeline for classification in histology
images. Using multiple instance learning, we attempt to predict the latent
membrane protein 1 (LMP1) status of nasopharyngeal carcinoma (NPC) based on
haematoxylin and eosin-stain (H&E) histology images. We utilised attention
mechanism with residual connection for our aggregation layers. In our 3-fold
cross-validation experiment, we achieved average accuracy, AUC and F1-score
0.936, 0.995 and 0.862, respectively. This method also allows us to examine the
model interpretability by visualising attention scores. To the best of our
knowledge, this is the first attempt to predict LMP1 status on NPC using deep
learning
Arp 302: Non-starburst Luminous Infrared Galaxies
Arp 302, a luminous infrared source (L_{IR} = 4.2x10^{11} Lsun), consisting
of two spiral galaxies (VV340A and VV340B) with nuclear separation of 40'', has
the highest CO luminosity known. Observations with the BIMA array at 5'' X 7''
resolution reveal that the CO emission is extended over 23.0 kpc in the edge-on
spiral galaxy, VV340A, corresponding to 6.7x10^{10} Msun of H_2. In the
companion face-on galaxy, VV340B, the CO emission is extended over ~10.0 kpc,
with 1.1x10^{10} Msun of H_2. The large CO extent is in strong contrast to
starburst systems, such as Arp 220, in which the CO extent is typically 1
kpc. Furthermore, (H_2) is found to be 6.0 Lsun/Msun throughout
both galaxies. Thus the high IR luminosity of Arp 302 is apparently not due to
starbursts in the nuclear regions, but is due to its unusually large amount of
molecular gas forming stars at a rate similar to giant molecular clouds in the
Milky Way disk. Arp 302 consists of a pair of very gas-rich spiral galaxies
that may be interacting and in a phase before a likely onset of starbursts.Comment: AAS Latex plus two postscript figures. ApJ Letters (accepted
Carboplatin and Etoposide With or Without Palifosfamide in Untreated Extensive-Stage Small-Cell Lung Cancer: A Multicenter, Adaptive, Randomized Phase III Study (MATISSE)
Purpose
To evaluate the efficacy of the addition of palifosfamide to carboplatin and etoposide in extensive stage (ES) small-cell lung cancer (SCLC).
Patients and Methods
MATISSE was a randomized, open-label, adaptive phase III study. Previously untreated patients with ES SCLC were randomly assigned in a 1:1 fashion to receive carboplatin at area under the serum concentration-time curve 5 on day 1 plus etoposide 100 mg/m2 per day on days 1 to 3 every 21 days (CE) or carboplatin at area under the serum concentration-time curve 4 on day 1 plus etoposide 100 mg/m2 per day plus palifosfamide 130 mg/m2 per day on days 1 to 3 every 21 days (PaCE). The primary end point was overall survival.
Results
In all, 188 patients were enrolled; 94 patients received CE and 94 patients received PaCE. The median age on both arms was 61 years. Six cycles of chemotherapy were completed on both arms of the study by approximately 50% of the patients. Serious adverse events were documented and did not differ significantly between patients receiving PaCE and those receiving CE. Median overall survival was similar between both arms with 10.03 months on PaCE and 10.37 months on CE (P = .096).
Conclusion
The addition of palifosfamide to CE failed to improve survival in ES SCLC
An unexpected twist to the activation of IKKβ:TAK1 primes IKKβ for activation by autophosphorylation
IKKβ {IκB [inhibitor of NF-κB (nuclear factor κB)] kinase β} is required to activate the transcription factor NF-κB, but how IKKβ itself is activated in vivo is still unclear. It was found to require phosphorylation by one or more ‘upstream’ protein kinases in some reports, but by autophosphorylation in others. In the present study, we resolve this contro-versy by demonstrating that the activation of IKKβ induced by IL-1 (interleukin-1) or TNF (tumour necrosis factor) in embryonic fibroblasts, or by ligands that activate Toll-like receptors in macrophages, requires two distinct phosphorylation events: first, the TAK1 [TGFβ (transforming growth factor β)-activated kinase-1]-catalysed phosphorylation of Ser(177) and, secondly, the IKKβ-catalysed autophosphorylation of Ser(181). The phosphorylation of Ser(177) by TAK1 is a priming event required for the subsequent autophosphorylation of Ser(181), which enables IKKβ to phosphorylate exogenous substrates. We also provide genetic evidence which indicates that the IL-1-stimulated, LUBAC (linear ubiquitin chain assembly complex)-catalysed formation of linear ubiquitin chains and their interaction with the NEMO (NF-κB essential modulator) component of the canonical IKK complex permits the TAK1-catalysed priming phosphorylation of IKKβ at Ser(177) and IKKα at Ser(176). These findings may be of general significance for the activation of other protein kinases
Experimental investigation of flow-induced vibration of a rotating circular cylinder
While flow-induced vibration of bluff bodies has been extensively studied over the last half-century, only limited attention has been given to flow-induced vibration of elastically mounted rotating cylinders. Since recent low-Reynolds-number numerical work suggests that rotation can enhance or suppress the natural oscillatory response, the former could find applications in energy harvesting and the latter in vibration control. The present experimental investigation characterises the dynamic response and wake structure of a rotating circular cylinder undergoing vortex-induced vibration at a low mass ratio (m∗ = 5.78) over the reduced velocity range leading to strong oscillations. The experiments were conducted in a free-surface water channel with the cylinder vertically mounted and attached to a motor that provided constant rotation. Springs and an air-bearing system allow the cylinder to undertake low-damped transverse oscillations. Under cylinder rotation, the normalised frequency response was found to be comparable to that of a freely vibrating non-rotating cylinder. At reduced velocities consistent with the upper branch of a non-rotating transversely oscillating cylinder, the maximum oscillation amplitude increased with non-dimensional rotation rate up to α ≈ 2. Beyond this, there was a sharp decrease in amplitude. Notably, this critical value corresponds approximately to the rotation rate at which vortex shedding ceases for a non-oscillating rotating cylinder. Remarkably, at α = 2 there was approximately an 80% increase in the peak amplitude response compared to that of a non-rotating cylinder. The observed amplitude response measured over the Reynolds-number range of (1100 Re 6300) is significantly different from numerical predictions and other experimental results recorded at significantly lower Reynolds numbers
Experimental investigation of flow-induced vibration of a sinusoidally rotating circular cylinder
The present experimental investigation characterises the dynamic response and wake structure of a sinusoidally rotating circular cylinder with a low mass ratio (defined as the ratio of the total oscillating mass to the displaced fluid mass) undergoing cross-stream flow-induced vibration (FIV). The study covers a wide parameter space spanning the forcing rotary oscillation frequency ratio
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Improved Quality of 3D-Printed Tissue Constructs Through Enhanced Mixing of Alginate Hydrogels
While alginate hydrogel is a desirable material platform for Solid Freeform Fabrication (SFF) of
cell-seeded tissue engineering scaffolds, achieving consistently high-quality results can be
challenging. Local variations in the material properties cause inconsistent material deposition
behavior and consequently decrease the resultant geometric fidelity of the construct. The effects
of gel mixing on material property consistency, geometric fidelity, and cell viability were
characterized in an attempt to improve the formulation’s compatibility with SFF processing.
Material homogeneity was quantified through a novel experimental setup composed of an
EnduraTEC mechanical test-frame and custom syringe-extrusion jig. Cell viability and
geometric fidelity were assessed using standard protocol. The baseline mechanical stiffness of
the printed samples was 16±3 kPa (n=6). We found that increasing mixing reduced material
inconsistency and improved geometric fidelity, without adversely affecting cell viability: the
printed construct quality was drastically improved by increasing mixing well beyond previously
established limits.Mechanical Engineerin
Transition between immune and disease states in a cellular automaton model of clonal immune response
In this paper we extend the Celada-Seiden (CS) model of the humoral immune
response to include infectious virus and cytotoxic T lymphocytes (cellular
response). The response of the system to virus involves a competition between
the ability of the virus to kill the host cells and the host's ability to
eliminate the virus. We find two basins of attraction in the dynamics of this
system, one is identified with disease and the other with the immune state.
There is also an oscillating state that exists on the border of these two
stable states. Fluctuations in the population of virus or antibody can end the
oscillation and drive the system into one of the stable states. The
introduction of mechanisms of cross-regulation between the two responses can
bias the system towards one of them. We also study a mean field model, based on
coupled maps, to investigate virus-like infections. This simple model
reproduces the attractors for average populations observed in the cellular
automaton. All the dynamical behavior connected to spatial extension is lost,
as is the oscillating feature. Thus the mean field approximation introduced
with coupled maps destroys oscillations.Comment: 27 pages LaTeX + 7 Figures Postscrip
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