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result(s) for
"Guan, J."
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Challenging local realism with human choices
2018
A Bell test is a randomized trial that compares experimental observations against the philosophical worldview of local realism
1
, in which the properties of the physical world are independent of our observation of them and no signal travels faster than light. A Bell test requires spatially distributed entanglement, fast and high-efficiency detection and unpredictable measurement settings
2
,
3
. Although technology can satisfy the first two of these requirements
4
–
7
, the use of physical devices to choose settings in a Bell test involves making assumptions about the physics that one aims to test. Bell himself noted this weakness in using physical setting choices and argued that human ‘free will’ could be used rigorously to ensure unpredictability in Bell tests
8
. Here we report a set of local-realism tests using human choices, which avoids assumptions about predictability in physics. We recruited about 100,000 human participants to play an online video game that incentivizes fast, sustained input of unpredictable selections and illustrates Bell-test methodology
9
. The participants generated 97,347,490 binary choices, which were directed via a scalable web platform to 12 laboratories on five continents, where 13 experiments tested local realism using photons
5
,
6
, single atoms
7
, atomic ensembles
10
and superconducting devices
11
. Over a 12-hour period on 30 November 2016, participants worldwide provided a sustained data flow of over 1,000 bits per second to the experiments, which used different human-generated data to choose each measurement setting. The observed correlations strongly contradict local realism and other realistic positions in bipartite and tripartite
12
scenarios. Project outcomes include closing the ‘freedom-of-choice loophole’ (the possibility that the setting choices are influenced by ‘hidden variables’ to correlate with the particle properties
13
), the utilization of video-game methods
14
for rapid collection of human-generated randomness, and the use of networking techniques for global participation in experimental science.
The BIG Bell Test, which used an online video game with 100,000 participants worldwide to provide random bits to 13 quantum physics experiments, contradicts the Einstein–Podolsky–Rosen worldview of local realism.
Journal Article
Inhibition of GPX4 enhances CDK4/6 inhibitor and endocrine therapy activity in breast cancer
2024
CDK4/6 inhibition in combination with endocrine therapy is the standard of care for estrogen receptor (ER+) breast cancer, and although cytostasis is frequently observed, new treatment strategies that enhance efficacy are required. Here, we perform two independent genome-wide CRISPR screens to identify genetic determinants of CDK4/6 and endocrine therapy sensitivity. Genes involved in oxidative stress and ferroptosis modulate sensitivity, with GPX4 as the top sensitiser in both screens. Depletion or inhibition of GPX4 increases sensitivity to palbociclib and giredestrant, and their combination, in ER+ breast cancer models, with GPX4 null xenografts being highly sensitive to palbociclib. GPX4 perturbation additionally sensitises triple negative breast cancer (TNBC) models to palbociclib. Palbociclib and giredestrant induced oxidative stress and disordered lipid metabolism, leading to a ferroptosis-sensitive state. Lipid peroxidation is promoted by a peroxisome AGPAT3-dependent pathway in ER+ breast cancer models, rather than the classical ACSL4 pathway. Our data demonstrate that CDK4/6 and ER inhibition creates vulnerability to ferroptosis induction, that could be exploited through combination with GPX4 inhibitors, to enhance sensitivity to the current therapies in breast cancer.
While CDK4/6 inhibitors (CDK4/6i) have improved outcomes for breast cancer patients, estrogen receptor (ER + ) breast cancers often develop resistance, and triple negative breast cancer (TNBC) show poor sensitivity. Here, the authors identify a vulnerability of CDK4/6i treated ER+ and TNBC on ferroptosis and identify the combination of CDK4/6i and GPX4 inhibition as synergistic.
Journal Article
Tyrosine phosphorylation of cofilin at Y68 by v-Src leads to its degradation through ubiquitin–proteasome pathway
2010
Cofilin is a major regulator of actin dynamics involved in the regulation of cell spreading and migration through its actin depolymerizing and severing activities. v-Src is an activated Src tyrosine kinase and a potent oncogene known to phosphorylate a variety of cellular proteins in cell transformation process including altered cell adhesion, spreading and migration. Recently, it has been suggested that cofilin is a potential substrate of v-Src (Rush
et al.
, 2005). Here, we show direct tyrosine phosphorylation of cofilin by v-Src and identify Y68 as the major phosphorylation site. Cofilin phosphorylation at Y68 did not change its activity
per se
, but induced increased ubiquitination of cofilin and its degradation through the proteosome pathway. Furthermore, the negative effect of cofilin on cellular F-actin contents was inhibited by coexpression of v-Src, whereas that of cofilin mutant Y68F (Y68 mutated to F) was not affected, suggesting that v-Src-mediated cofilin phosphorylation at Y68 is required for the degradation of cofilin
in vivo
. Lastly, inhibition of cell spreading by v-Src was rescued partially by coexpression of cofilin, and to a greater extent by the Y68F mutant, which is not subjected to v-Src-induced degradation through phosphorylation, suggesting that v-Src-mediated changes in cell spreading is, at least in part, through inhibiting the function of cofilin through phosphorylating it at Y68. Together, these results suggest a novel mechanism by which cofilin is regulated by v-Src through tyrosine phosphorylation at Y68 that triggers the degradation of cofilin through ubiquitination–proteosome pathway and consequently inhibits cofilin activity in reducing cellular F-actin contents and cell spreading.
Journal Article
Inhibition of ATG12-mediated autophagy by miR-214 enhances radiosensitivity in colorectal cancer
2018
Radioresistance hampers success in the treatment of patients with advanced colorectal cancer (CRC). Improving our understanding of the underlying mechanisms of radioresistance could increase patients’ response to irradiation (IR). MicroRNAs are a class of small RNAs involved in tumor therapy response to radiation. Here we found that miR-214 was markedly decreased in CRC cell lines and blood of CRC patients after IR exposure. Meanwhile, autophagy was enhanced in irradiated CRC cells. Mechanically, ATG12 was predicted and identified as a direct target of miR-214 by dual luciferase assay, qPCR, and Western blot. In vitro and in vivo experiments showed that miR-214 promoted radiosensitivity by inhibiting IR-induced autophagy. Restoration of ATG12 attenuated miR-214-mediated inhibition of cell growth and survival in response to IR. Importantly, miR-214 was highly expressed in radiosensitive CRC specimens and negatively correlated with plasma level of CEA. Moreover, ATG12 and LC3 expressions were increased in radioresistant CRC specimens. Our study elucidates that miR-214 promotes radiosensitivity by inhibition of ATG12-mediated autophagy in CRC. Importantly, miR-214 is a determinant of CRC irradiation response and may serve as a potential therapeutic target in CRC treatment.
Journal Article
Design and construction of the near-earth space plasma simulation system of the Space Plasma Environment Research Facility
2024
Our earth is immersed in the near-earth space plasma environment, which plays a vital role in protecting our planet against the solar-wind impact and influencing space activities. It is significant to investigate the physical processes dominating the environment, for deepening our scientific understanding of it and improving the ability to forecast the space weather. As a crucial part of the National Major Scientific and Technological Infrastructure–Space Environment Simulation Research Infrastructure (SESRI) in Harbin, the Space Plasma Environment Research Facility (SPERF) builds a system to replicate the near-earth space plasma environment in the laboratory. The system aims to simulate the three-dimensional (3-D) structure and processes of the terrestrial magnetosphere for the first time in the world, providing a unique platform to reveal the physics of the 3-D asymmetric magnetic reconnection relevant to the earth's magnetopause, wave–particle interaction in the earth's radiation belt, particles’ dynamics during the geomagnetic storm, etc. The paper will present the engineering design and construction of the near-earth space plasma simulation system of the SPERF, with a focus on the critical technologies that have been resolved to achieve the scientific goals. Meanwhile, the possible physical issues that can be studied based on the apparatus are sketched briefly. The earth-based system is of great value in understanding the space plasma environment and supporting space exploration.
Journal Article
DRAM1 regulates apoptosis through increasing protein levels and lysosomal localization of BAX
DRAM1 (
DNA damage-regulated autophagy modulator 1
) is a TP53 target gene that modulates autophagy and apoptosis. We previously found that DRAM1 increased autophagy flux by promoting lysosomal acidification and protease activation. However, the molecular mechanisms by which DRAM1 regulates apoptosis are not clearly defined. Here we report a novel pathway by which DRAM1 regulates apoptosis involving BAX and lysosomes. A549 or HeLa cells were treated with the mitochondrial complex II inhibitor, 3-nitropropionic acid (3NP), or an anticancer drug, doxorubicin. Changes in the protein and mRNA levels of BAX and DRAM1 and the role of DRAM1 in BAX induction were determined. The interaction between DRAM1 and BAX and its effect on BAX degradation, BAX lysosomal localization, the release of cathepsin B and cytochrome
c
by BAX and the role of BAX in 3NP- or doxorubicin-induced cell death were studied. The results showed that BAX, a proapoptotic protein, was induced by DRAM1 in a transcription-independent manner. BAX was degraded by autophagy under basal conditions; however, its degradation was inhibited when DRAM1 expression was induced. There was a protein interaction between DRAM1 and BAX and this interaction prolonged the half-life of BAX. Furthermore, upregulated DRAM1 recruited BAX to lysosomes, leading to the release of lysosomal cathepsin B and cleavage of BID (BH3-interacting domain death agonist). BAX mediated the release of mitochondrial cytochrome
c
, activation of caspase-3 and cell death partially through the lysosome-cathepsin B-tBid pathway. These results indicate that DRAM1 regulates apoptosis by inhibiting BAX degradation. In addition to mitochondria, lysosomes may also be involved in BAX-initiated apoptosis.
Journal Article
Gauss–Bonnet Theorems for Lorentzian and Spacelike Surfaces Associated to Canonical Connections in the Lorentzian Heisenberg Group
2023
Canonical connections play important roles in studying the differential geometry properties of submanifolds in Lie groups. We define the first kind of canonical connection and the second canonical connection on Lorentzian approximations of the Heisenberg group. Moreover, we give the definitions of intrinsic curvature of a regular curve as well of intrinsic geodesic curvature of regular curves on Lorentzian and spacelike surfaces and of intrinsic Gaussian curvature of Lorentzian and spacelike surfaces away from characteristic points. Furthermore, we derive the expressions of those curvatures and prove Gauss–Bonnet Theorems for the Lorentzian and spacelike surfaces associated to canonical connections in the Lorentzian Heisenberg group.
Journal Article
Romosozumab or alendronate for fracture prevention in East Asian patients: a subanalysis of the phase III, randomized ARCH study
2020
SummaryRomosozumab, a sclerostin antibody, exerts dual effect to increase bone formation and decrease bone resorption. Among high-risk postmenopausal East Asian women, romosozumab followed by alendronate was associated with lower incidences of fractures vs alendronate alone. Romosozumab demonstrates potential to address an unmet need in osteoporosis management in Asia.IntroductionRomosozumab, a sclerostin antibody, exerts dual effect to increase bone formation and decrease bone resorption. The global ARCH study demonstrated superiority of romosozumab followed by alendronate in reducing fracture risk in high-risk postmenopausal osteoporotic women vs alendronate alone. We report outcomes among ARCH East Asian patients.MethodsIn ARCH, 4093 postmenopausal osteoporotic women with fragility fracture were randomized 1:1 to monthly romosozumab 210 mg or weekly alendronate 70 mg for 12 months, both followed by open-label alendronate. Primary endpoints were incidence of new vertebral fracture (VF) at 24 months and clinical fracture at primary analysis (confirmed fractures in ≥ 330 patients and all patients had opportunity to attend month 24 visit). This post hoc analysis was not powered to detect fracture-rate differences.ResultsThis analysis included 275 patients from Hong Kong, Korea, and Taiwan. Romosozumab followed by alendronate reduced risk of new VFs at 24 months by 60% (P = 0.11) and clinical fractures at primary analysis by 44% (P = 0.15) vs alendronate alone. Romosozumab followed by alendronate significantly increased mean bone mineral density at 24 months from baseline by a further 9.0%, 3.3%, and 3.0% at the lumbar spine, total hip, and femoral neck vs alendronate alone. Adverse event (AE) rates, including positively adjudicated serious cardiovascular AEs (1.6% vs 1.4% at 12 months for romosozumab vs alendronate), were similar across treatment groups.ConclusionsConsistent with the global analysis, romosozumab followed by alendronate was associated with lower incidences of new vertebral, clinical, non-vertebral, and hip fractures vs alendronate alone among East Asian patients.
Journal Article
Therapeutic efficacy of zoledronic acid combined with calcitriol in elderly patients receiving total hip arthroplasty or hemiarthroplasty for osteoporotic femoral neck fracture
2021
SummaryZoledronic acid could improve the clinical outcome in elderly patients receiving total hip arthroplasty or hemiarthroplasty for osteoporotic femoral neck fracture in the 1-year prospective study.IntroductionTo validate the therapeutic efficacy of zoledronic acid (ZOL) in elderly patients with femoral neck fracture who received total hip arthroplasty (THA) or hemiarthroplasty (HA).MethodsIncluded in this study were 95 elderly patients with femoral neck fractures who received THA/HA between August 2015 and June 2018. They were randomized into a ZOL group and a control group. Patients in ZOL group received a yearly single dose of 5 mg ZOL intravenous injection plus 0.5 μg/day calcitriol and 1000 mg/day calcium carbonate 2 days before THA or HA. Patients in the control group were treated with the same dose of calcitriol and calcium carbonate only without ZOL. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry. Bone metabolism markers including the total extension of the peptide type I collagen amino end (P1NP) and beta collagen degradation product (β-CTX) were obtained by serum examination. The postoperative functional outcome was assessed using Harris Hip Score (HHS).ResultsDuring the follow-up period, BMD in the ZOL group was improved and significantly higher than that in the control group at 6 and 12 months post-operation. Bone metabolism markers P1NP and β-CTX in ZOL group remained at a relatively low level as compared with that in the control group at 6 months after treatment. No significant difference in the mean HHS and the excellent/good rate of joint function was observed during the follow-up period between the two groups. The occurrence of adverse events in the ZOL group was significantly higher than that in the control group.ConclusionsA single infusion of ZOL shows promise in improving BMD of the healthy side of the femoral neck, lumbar spine, and total hip and decreasing the level of bone markers, which may improve the clinical outcome of patients with osteoporotic femoral neck fractures receiving THA/HA.
Journal Article