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Find video protocols related to scientific articles indexed in Pubmed.
A mitochondrial switch promotes tumor metastasis.
Cell Rep
PUBLISHED: 06-04-2014
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Metastatic progression of cancer is associated with poor outcome, and here we examine metabolic changes underlying this process. Although aerobic glycolysis is known to promote metastasis, we have now identified a different switch primarily affecting mitochondria. The switch involves overload of the electron transport chain (ETC) with preserved mitochondrial functions but increased mitochondrial superoxide production. It provides a metastatic advantage phenocopied by partial ETC inhibition, another situation associated with enhanced superoxide production. Both cases involved protein tyrosine kinases Src and Pyk2 as downstream effectors. Thus, two different events, ETC overload and partial ETC inhibition, promote superoxide-dependent tumor cell migration, invasion, clonogenicity, and metastasis. Consequently, specific scavenging of mitochondrial superoxide with mitoTEMPO blocked tumor cell migration and prevented spontaneous tumor metastasis in murine and human tumor models.
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High TMEM45A expression is correlated to epidermal keratinization.
Exp. Dermatol.
PUBLISHED: 03-30-2014
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TMEM45A (DERP7, DNAPTP4 or FLJ10134) gene, belonging to the TMEM family encoding predicted transmembrane proteins, is highly expressed in epidermal keratinocytes. To investigate the potential involvement of TMEM45A during the differentiation and keratinization processes, its expression has been characterized in normal human keratinocytes and the protein subcellular localization has been studied in this cell type, both in vitro and in vivo. TMEM45A expression is upregulated with differentiation, either induced by cultured keratinocyte confluence or enhanced Ca(2+) concentration in medium. In vivo, TMEM45A mRNA and protein are mostly found in the granular layer of the epidermis. TMEM45A expression is linked to keratinization, as accumulation of the protein is detected in native and reconstructed epidermis as well as in thymic Hassal bodies, but not in non-keratinized stratified epithelia. At the subcellular level, co-detection with ER and Golgi markers reveals that TM protein 45A is associated with the Golgi apparatus and more specifically with the trans-Golgi/trans-Golgi network in vitro and in granular layer in vivo. The protein is neither related to lysosomes nor transported within corneodesmosin-containing lamellar bodies. These data demonstrate a strong correlation between TMEM45A expression and epidermal keratinization, indicating the relevance of this gene in this process.
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(89)Zr-labeled anti-endoglin antibody-targeted gold nanoparticles for imaging cancer: implications for future cancer therapy.
Nanomedicine (Lond)
PUBLISHED: 02-18-2014
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Antibody-labeled gold nanoparticles represent an attractive tool for cancer imaging and therapy. In this study, the anti-CD105 antibody was conjugated with gold nanoparticles (AuNPs) for the first time. The antibody biodistribution in mice before and after conjugation to AuNPs was studied, with a focus on tumor targeting.
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Meta-analysis and gene set analysis of archived microarrays suggest implication of the spliceosome in metastatic and hypoxic phenotypes.
PLoS ONE
PUBLISHED: 01-01-2014
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We propose to make use of the wealth of underused DNA chip data available in public repositories to study the molecular mechanisms behind the adaptation of cancer cells to hypoxic conditions leading to the metastatic phenotype. We have developed new bioinformatics tools and adapted others to identify with maximum sensitivity those genes which are expressed differentially across several experiments. The comparison of two analytical approaches, based on either Over Representation Analysis or Functional Class Scoring, by a meta-analysis-based approach, led to the retrieval of known information about the biological situation - thus validating the model - but also more importantly to the discovery of the previously unknown implication of the spliceosome, the cellular machinery responsible for mRNA splicing, in the development of metastasis.
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Low-dose hypersensitivity and bystander effect are not mutually exclusive in A549 lung carcinoma cells after irradiation with charged particles.
Radiat. Res.
PUBLISHED: 10-14-2013
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The purpose of this study was to measure survival fraction of A549 lung carcinoma cells irradiated with charged particles of various LET and to determine mechanisms responsible for enhanced cell killing in the low-dose region. A549 cells were irradiated with a broadbeam of either 10 and 25 keV/?m protons or 100 keV/?m alpha particles and then processed for clonogenic assays and phospho-histone H3 staining. The survival fraction of unirradiated A549 cells co-cultured with irradiated cells was also evaluated. A549 cells were shown to exhibit low-dose hypersensitivity (HRS) for both protons and alpha particles. The dose threshold at which HRS occurs decreased with increasing linear energy transfer (LET), whereas ?s, the initial survival curve slope, increased with increasing LET. In addition, the enhanced cell killing observed after irradiation with alpha particles was partly attributed to the bystander effect, due to the low proportion of hit cells at very low doses. Co-culture experiments suggest a gap junction-mediated bystander signal. Our results indicate that HRS is likely to be dependent on LET, and that a bystander effect and low-dose hypersensitivity may co-exist within a given cell line.
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Effects of the dual TP receptor antagonist and thromboxane synthase inhibitor EV-077 on human endothelial and vascular smooth muscle cells.
Biochem. Biophys. Res. Commun.
PUBLISHED: 10-11-2013
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The prothrombotic mediator thromboxane A2 is derived from arachidonic acid metabolism through the cyclooxygenase and thromboxane synthase pathways, and transduces its effect through the thromboxane prostanoid (TP) receptor. The aim of this study was to determine the effect of the TP receptor antagonist and thromboxane synthase inhibitor EV-077 on inflammatory markers in human umbilical vein endothelial cells and on human coronary artery smooth muscle cell proliferation. To this end, mRNA levels of different proinflammatory mediators were studied by real time quantitative PCR, supernatants were analyzed by enzyme immune assay, and cell proliferation was assessed using WST-1. EV-077 significantly decreased mRNA levels of ICAM-1 and PTX3 after TNF? incubation, whereas concentrations of 6-keto PGF1? in supernatants of endothelial cells incubated with TNF? were significantly increased after EV-077 treatment. Although U46619 did not alter coronary artery smooth muscle cell proliferation, this thromboxane mimetic enhanced the proliferation induced by serum, insulin and growth factors, which was significantly inhibited by EV-077. In conclusion, EV-077 inhibited TNF?-induced endothelial inflammation and reduced the enhancement of smooth muscle cell proliferation induced by a thromboxane mimetic, supporting that the thromboxane pathway may be associated with early atherosclerosis in terms of endothelial dysfunction and vascular hypertrophy.
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Low dose hypersensitivity following in vitro cell irradiation with charged particles: Is the mechanism the same as with X-ray radiation?
Int. J. Radiat. Biol.
PUBLISHED: 09-13-2013
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Purpose: Among the low dose effects that have been discovered during the past decade, the low dose hypersensitivity (HRS) is of prime importance. This phenomenon, compared to irradiation at higher doses used in conventional radiotherapy, enhances cell killing per unit dose at low doses and is followed by an induced radioresistance (IRR) effect. On survival fraction curves, a deviation from the linear quadratic model can be observed. HRS has mainly been studied after irradiation with sparsely ionizing radiation. Little work has been done to check its actual existence after irradiation with medium and high linear energy transfer (LET) particles. This article reviews recent studies involving HRS following irradiation of rodent and human cells with protons, alpha particles and carbon ions and assesses the applicability of a photon HRS model to charged particles. Conclusion: We propose that the HRS threshold dose and the radiosensitive parameter ?s may be LET and deoxyribonucleic acid (DNA) damage-clustering dependent. Combining the use of high-LET particles at low doses and chemotherapy strategies increasing the proportion of HRS-sensitive cells could become a good candidate treatment for radioresistant cancers.
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Differential effect of hypoxia on etoposide-induced DNA damage response and p53 regulation in different cell types.
J. Cell. Physiol.
PUBLISHED: 05-10-2013
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Among the main causes of cancer cell resistance to chemotherapy are p53 mutation and hypoxic tumor microenvironment. However, the effect of hypoxia can be very different from one cell type to the other. We studied the effect of hypoxia on the etoposide-induced cell death in two cancer cell lines, HepG2 and A549 cells. Hypoxia decreased etoposide-induced apoptosis in HepG2 cells but not in A549 cells. Here, we evidenced two pathways, known to play important roles in cancer cell resistance, that are differently affected by hypoxia in these two cell types. First, in HepG2 cells, hypoxia decreased p53 protein level and activity by acting post-transcriptionally and independently of HIF-1. The results suggest an effect of hypoxia on p53 translation. On the other hand, in A549 cells, no effect of hypoxia was observed on p53 level. Secondly, hypoxia decreased DNA damage response in HepG2 cells while this was not the case in A549 cells. Indeed, a decrease in the phosphorylation level of CHK2 and H2AX with a decrease in ATM activity was observed. Importantly, these results evidenced that hypoxia can prevent cancer cell apoptosis by acting at different levels in the cell and that these effects are strongly cell-type dependent.
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Comparison of X-ray and alpha particle effects on a human cancer and endothelial cells: survival curves and gene expression profiles.
Radiother Oncol
PUBLISHED: 02-15-2013
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Tumours are now considered as complex tissues including endothelial cells of the tumour vasculature, which can decrease radiotherapy efficacy. It is thus important to better characterise the response of both types of cells to irradiation. This study investigated the effects of X-ray and alpha particle irradiation on cancer and endothelial cells.
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Antibody-functionalized nanoparticles for imaging cancer: influence of conjugation to gold nanoparticles on the biodistribution of 89Zr-labeled cetuximab in mice.
Contrast Media Mol Imaging
PUBLISHED: 02-06-2013
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Antibody-labeled gold nanoparticles represent a promising novel tool regarding cancer imaging and therapy. Nevertheless, the characterization of biodistribution of such immunonanocarriers has been poorly documented. In this study, the biodistribution of (89)Zr-labeled cetuximab before and after the coupling reaction to gold nanoparticles (AuNPs) was compared and the quantitative imaging performance of (89)Zr immuno-PET was evaluated. Cetuximab was functionalized with the desferal moiety and labeled with (89)Zr ((89)Zr-Df-Bz-NCS-cetuximab). AuNPs with a mean diameter of 5 nm were synthesized according a new method developed in the laboratory, and conjugated to (89)Zr-Df-Bz-NCS-cetuximab using carbodiimide chemistry (AuNPs-PPAA-cetuximab-(89)Zr). The two tracers were injected in A431 xenograft-bearing mice. Tumor and liver uptakes were assessed at different times after injection using quantitative PET imaging. The in vivo specificity of the binding was investigated using a saturating dose of unlabeled cetuximab. Radiolabeled cetuximab was conjugated to AuNPs with a coupling reaction yield >75%. All conjugates were stable in vitro and to a lesser extent in plasma. In vivo distribution studies revealed no significant difference in tumor uptake for cetuximab conjugated to nanoparticles up to 72 h after injection, compared with unconjugated cetuximab. Immuno-PET studies showed that AuNPs-PPAA-cetuximab-(89)Zr provided high tumor-to-background ratio. The liver uptake of AuNPs-PPAA-cetuximab-(89)Zr was higher, compared with (89)Zr-Df-Bz-NCS-cetuximab. In vivo blocking experiments demonstrated selective tumor targeting after coupling reaction. This study showed that the conjugation of AuNPs to cetuximab did not affect its tumor accumulation and that the efficacy of EGFR-targeted nanoparticles was unaltered. The (89)Zr-labeled cetuximab-targeted gold nanoparticles could be a valuable tool for theranostic purposes.
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A hybrid assembly by encapsulation of human cells within mineralised beads for cell therapy.
PLoS ONE
PUBLISHED: 01-23-2013
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The design of new technologies for treatment of human disorders such as protein deficiencies is a complex and difficult task. Particularly, the construction of artificial organs, based on the immunoisolation of protein-secreting cells, requires the use of suitable materials which have to be biocompatible with the immunoisolated cells and avoid any inappropriate host response.
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Low-LET proton irradiation of A549 non-small cell lung adenocarcinoma cells: dose response and RBE determination.
Radiat. Res.
PUBLISHED: 01-21-2013
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Since 1957, broad proton beam radiotherapy with a spread out Bragg peak has been used for cancer treatment. More recently, studies on the use of proton therapy in the treatment of non-small cell lung cancer (NSCLC) were performed and although the benefit of using protons for the treatment of NSCLC is recognized, more work is needed to gather additional data for the understanding of cell response. Human A549 cell survival was evaluated by colony forming assay 11 days after 10 keV/?m proton beam irradiation at 0.1 and 1 Gy/min. The residual energy of the proton beam at the location of the irradiated cells was 3.9 MeV. In parallel, early effects on the cell viability and DNA damage were assessed and DNA synthesis was measured. The survival curve obtained was fitted with both the linear and the induced-repair models, as a hyper-radiosensitivity was evidenced at very low doses. Above 0.5 Gy, a linear shape was observed with the ? parameter equal to 0.824 ± 0.029 Gy(-1). In addition, early cell death and cell proliferation arrest were enhanced. Moreover, a clear correlation between DNA damage and surviving fraction was observed. Finally, comparisons with X ray results indicate that proton irradiation at 10 keV/?m enhanced the tumor radiosensitivity with a significant dose-dependent decrease in the survival fraction. The RBE value of 1.9 ± 0.4 obtained for a 10% survival support this observation.
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The role of hypoxia-inducible factor 1? in determining the properties of castrate-resistant prostate cancers.
PLoS ONE
PUBLISHED: 01-16-2013
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Castrate-resistant prostate cancer (CRPC) is a lethal condition in patients receiving androgen deprivation therapy for prostate cancer (PC). Despite numerous studies showing the expression of HIF1? protein under normoxia in PC cell lines, the role of this normoxic HIF1? expression in chemo-resistance and migration has not been investigated previously. As no method is currently available to determine which tumors will progress to CRPC, the role of HIF1? in PC and its potential for predicting the development of CRPC was also investigated.
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Molecular aspects of cancer cell resistance to chemotherapy.
Biochem. Pharmacol.
PUBLISHED: 01-08-2013
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Cancer cell resistance to chemotherapy is still a heavy burden that impairs treatment of cancer patients. Both intrinsic and acquired resistance results from the numerous genetic and epigenetic changes occurring in cancer cells. Most of the hallmarks of cancer cells provide general mechanisms to sustain stresses such as the ones induced by chemotherapeutic drugs. Moreover, specific changes in the target bring resistance to specific drugs like modification in nucleotide synthesis enzymes upon anti-metabolite exposure, in microtubule composition upon spindle poison treatment, in topoisomerase activity upon topoisomerase inhibitor incubation or in intracellular signaling pathways when targeting tyrosine kinase receptors. Finally, the stemness properties of a few cancer cells as well as components of the tumor stroma, like fibroblasts and tumor-associated macrophages but also hypoxia, also help tumor to resist to anticancer agents. These processes provide an additional level of complexity to the understanding of the tumor resistance phenomenon. This review aims to describe the different general mechanisms as well as some examples of specific on target modifications inducing cancer cell resistance to chemotherapy at the molecular level. Perspectives to develop more efficient treatment, using genomic signature or more specific biomarkers to characterize putative resistance mechanisms in patients before choosing the more appropriate treatment, will also be discussed.
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Anti-cancer activities of pH- or heat-modified pectin.
Front Pharmacol
PUBLISHED: 01-01-2013
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Despite enormous efforts that have been made in the search for novel drugs and treatments, cancer continues to be a major public health problem. Moreover, the emergence of resistance to cancer chemotherapy often prevents complete remission. Researchers have thus turned to natural products mainly from plant origin to circumvent resistance. Pectin and pH- or heat-modified pectin have demonstrated chemopreventive and antitumoral activities against some aggressive and recurrent cancers. The focus of this review is to describe how pectin and modified pectin display these activities and what are the possible underlying mechanisms. The failure of conventional chemotherapy to reduce mortality as well as serious side effects make natural products, such as pectin-derived products, ideal candidates for exerting synergism in combination with conventional anticancer drugs.
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The peroxynitrite donor 3-morpholinosydnonimine activates Nrf2 and the UPR leading to a cytoprotective response in endothelial cells.
Cell. Signal.
PUBLISHED: 06-01-2011
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Endothelial dysfunction is associated with the formation of peroxynitrite, described to be toxic. Recent data also suggests that peroxynitrite is able to activate the protective Nrf2 pathway and/or the unfolded protein response (UPR). The aim of our work was to study the response of human endothelial cells to 3-morpholinosydnonimine (SIN-1), a peroxynitrite donor, and to highlight the possible protective roles of Nrf2 or the UPR pathway in this response. Immortal and primary human umbilical vein endothelial cells were exposed to SIN-1. SIN-1 incubation led to Nrf2 activation and to the overexpression of Nrf2-regulated genes, heme oxygenase-1 (HO-1) and NAD(P)H quinone oxidoreductase 1. We also demonstrated that this defensive response protected cells against cell death induced by serum starvation, by reducing apoptosis (monitored by caspase-3 activity and DNA fragmentation) and favoring autophagosome formation, as evidenced by LC3-II accumulation. Interestingly, we observed an activation of the UPR, with a rapid and significant overexpression of CHOP in serum starved cells stimulated with SIN-1. While siRNA mediated knockdown of CHOP had no effect on DNA fragmentation, the invalidation of Nrf2 or HO-1 by siRNA strongly increased DNA fragmentation, but also reinforced the SIN-1-induced LC3-II accumulation. This study shows that peroxynitrite, at least at sublethal concentrations and within a narrow concentration range, could exert protective effects on endothelial cells by modulating the balance between autophagy and apoptosis, through Nrf2-dependent pathways.
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Autophagy as a mediator of chemotherapy-induced cell death in cancer.
Biochem. Pharmacol.
PUBLISHED: 04-28-2011
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Since the 1940s, chemotherapy has been the treatment of choice for metastatic disease. Chemotherapeutic agents target proliferating cells, inducing cell death. For most of the history of chemotherapy, apoptosis was thought to be the only mechanism of drug-induced cell death. More recently, a second type of cell death pathway has emerged: autophagy, also called type II programmed cell death. Autophagy is a tightly regulated process by which selected components of a cell are degraded. It primarily functions as a cell survival adaptive mechanism during stress conditions. However, persistent stress can also promote extensive autophagy, leading to cell death, hence its name. Alterations in the autophagy pathway have been described in cancer cells that suggest a tumor-suppressive function in early tumorigenesis, but a tumor-promoting function in established tumors. Moreover, accumulating data indicate a role for autophagy in chemotherapy-induced cancer cell death. Here, we discuss some of the evidence showing autophagy-dependent cell death induced by anti-neoplastic agents in different cancer models. On the other hand, in some other examples, autophagy dampens treatment efficacy, hence providing a therapeutic target to enhance cancer cell killing. In this paper, we propose a putative mechanism that could reconcile these two opposite observations.
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Hybrid shell engineering of animal cells for immune protections and regulation of drug delivery: towards the design of "artificial organs".
PLoS ONE
PUBLISHED: 04-19-2011
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With the progress in medicine, the average human life expectancy is continuously increasing. At the same time, the number of patients who require full organ transplantations is augmenting. Consequently, new strategies for cell transplantation are the subject of great interest.
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BM-573 inhibits the development of early atherosclerotic lesions in Apo E deficient mice by blocking TP receptors and thromboxane synthase.
Prostaglandins Other Lipid Mediat.
PUBLISHED: 02-21-2011
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Atherosclerosis is the principal cause of mortality in industrialized countries. Its development is influenced by several mediators of which thromboxane A(2) (TXA(2)) and 8-iso-PGF(2?) have recently received a lot of attention. This study aimed to investigate the effect of a dual thromboxane synthase inhibitor and thromboxane receptor antagonist (BM-573) and ASA on lesion formation in apolipoprotein E-deficient mice. The combination of ASA and BM-573 was also studied. Plasma measurements demonstrated that the treatments did not affect body weight or plasma cholesterol levels. BM-573, but not ASA, significantly decreased atherogenic lesions as demonstrated by macroscopic analysis. Both treatments alone inhibited TXB(2) synthesis but only BM-573 and the combination therapy were able to decrease firstly, plasma levels of soluble intracellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) and secondly, the expression of these proteins in the aortic root of Apo E. These results were confirmed in endothelial cell cultures derived from human saphenous vein endothelial cells (HSVECs). In these cells, BM-573 also prevented the increased mRNA expression of ICAM-1 and VCAM-1 induced by U-46619 and 8-iso-PGF(2?). Our results show that a molecule combining receptor antagonism and thromboxane synthase inhibition is more efficient in delaying atherosclerosis in Apo E(-/-) mice than sole inhibition of TXA(2) formation.
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Lactate influx through the endothelial cell monocarboxylate transporter MCT1 supports an NF-?B/IL-8 pathway that drives tumor angiogenesis.
Cancer Res.
PUBLISHED: 02-07-2011
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Lactate generated from pyruvate fuels production of intracellular NAD(+) as an end result of the glycolytic process in tumors. Elevated lactate concentration represents a good indicator of the metabolic adaptation of tumors and is actually correlated to clinical outcome in a variety of human cancers. In this study, we investigated whether lactate could directly modulate the endothelial phenotype and thereby tumor vascular morphogenesis and perfusion. We found that lactate could enter endothelial cells through the monocarboxylate transporter MCT-1, trigger the phosphorylation/degradation of I?B?, and then stimulate an autocrine NF-?B/IL-8 (CXCL8) pathway driving cell migration and tube formation. These effects were prevented by 2-oxoglutarate and reactive oxygen species (ROS) inhibitors, pointing to a role for prolyl-hydroxylase and ROS in the integration of lactate signaling in endothelial cells. PHD2 silencing in endothelial cells recapitulated the proangiogenic effects of lactate, whereas a blocking IL-8 antibody or IL-8-targeting siRNA prevented them. Finally, we documented in mouse xenograft models of human colorectal and breast cancer that lactate release from tumor cells through the MCT4 (and not MCT1) transporter is sufficient to stimulate IL-8-dependent angiogenesis and tumor growth. In conclusion, our findings establish a signaling role for lactate in endothelial cells and they identify the lactate/NF-?B/IL-8 pathway as an important link between tumor metabolism and angiogenesis.
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Surface properties and cell adhesion onto allylamine-plasma and amine-plasma coated glass coverslips.
J Mater Sci Mater Med
PUBLISHED: 01-18-2011
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Surface properties of nanoparticles to be used for radioimmunotherapy need to be optimized to allow antibody conjugation while ensuring biocompatibility. We aimed to investigate cell adhesion and proliferation onto different coatings to be used for nanoparticles. C, CH(x) or SiO(x) coatings deposited onto glass coverslips by magnetron deposition as well as nitrogen functionalized materials synthetized using different reactive sputtering conditions and PPAA (plasma polymerized allylamine) coating, were compared. Amine functionalization did increase hydrophilicity in all the materials tested. Biocompatibility was assessed by measuring cell viability, morphology, attachment, spreading, and pro-inflammatory cytokine secretion. The results show that C and CN(x) were the most biocompatible substrates while SiO(x) and SiO(x)N(y) were the most toxic materials. PPAA coatings displayed unexpectedly an intermediate biocompatibility. A correlation could be observed between wettability and cell proliferation except for C coated surface, indicating that more complex processes than hydrophilicity alone are taking place that affect cell functions.
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Anti-apoptotic role of HIF-1 and AP-1 in paclitaxel exposed breast cancer cells under hypoxia.
Mol. Cancer
PUBLISHED: 07-13-2010
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Hypoxia is a hallmark of solid tumors and is associated with metastases, therapeutic resistance and poor patient survival.
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BNIP3 protects HepG2 cells against etoposide-induced cell death under hypoxia by an autophagy-independent pathway.
Biochem. Pharmacol.
PUBLISHED: 06-02-2010
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Tumor hypoxia is a common characteristic of most solid tumors and is correlated with poor prognosis for patients partly because hypoxia promotes resistance to cancer therapy. Hypoxia selects cancer cells that are resistant to apoptosis and allows the onset of mechanisms that promote cancer cells survival including autophagy. Previously, we showed that human hepatoma HepG2 cells were protected under hypoxia against the etoposide-induced apoptosis. In this study, respective putative contribution of autophagy and BNIP3 in the protection conferred by hypoxia against the etoposide-induced apoptosis was investigated. We report that autophagy is induced by etoposide, a process that is not affected by hypoxic conditions. Using Atg5 siRNA, we show that etoposide-induced autophagy promotes apoptotic cell death under normoxia but not under hypoxia. Then, we investigated whether the hypoxia-induced protein BNIP3 could explain the different effect of autophagy on cell death under hypoxia or normoxia. We show that the silencing of BNIP3 does not affect autophagy whatever the pO(2) but participates in the protective effect of hypoxia against etoposide-induced apoptosis. Together, these results suggest that autophagy might be involved in etoposide-induced cell death only under normoxia and that BNIP3 is a major effector of the protective mechanism conferred by hypoxia to protect cancer cells against etoposide-induced apoptotic cell death.
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Meta-analysis of archived DNA microarrays identifies genes regulated by hypoxia and involved in a metastatic phenotype in cancer cells.
BMC Cancer
PUBLISHED: 04-30-2010
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Metastasis is a major cancer-related cause of death. Recent studies have described metastasis pathways. However, the exact contribution of each pathway remains unclear. Another key feature of a tumor is the presence of hypoxic areas caused by a lack of oxygen at the center of the tumor. Hypoxia leads to the expression of pro-metastatic genes as well as the repression of anti-metastatic genes. As many Affymetrix datasets about metastasis and hypoxia are publicly available and not fully exploited, this study proposes to re-analyze these datasets to extract new information about the metastatic phenotype induced by hypoxia in different cancer cell lines.
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A p38(MAPK)/HIF-1 pathway initiated by UVB irradiation is required to induce Noxa and apoptosis of human keratinocytes.
J. Invest. Dermatol.
PUBLISHED: 04-15-2010
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The signal transduction pathways leading to apoptosis of human keratinocytes responding to UVB irradiation are complex and not completely understood. Previously, we reported that in UVB-irradiated keratinocytes, p38(MAPK) instigates Bcl-2-associated X protein (Bax) activation and mitochondrial apoptosis. However, the molecular mechanism underlying the pro-apoptotic function of p38(MAPK) remained unclear. Here, we show that in UVB-treated human primary keratinocytes the activation of p38(MAPK) is necessary to upregulate Noxa, a BH3-only pro-apoptotic dominantly induced by UVB and required for apoptosis. Whereas p53-silencing was marginally cytoprotective and poorly affected Noxa expression, p38(MAPK) inhibition in p53-silenced keratinocytes or in p53(-/-) cells could still efficiently prevent Noxa induction and intrinsic apoptosis after UVB, indicating that p38(MAPK) signals mainly through p53-independent mechanisms. Furthermore, p38(MAPK) was required for the induction and activation of hypoxia-inducible factor 1 (HIF-1) in response to UVB, and HIF-1 knockdown reduced Noxa expression and apoptosis. In UVB-irradiated keratinocytes, Noxa targeted the anti-apoptotic myeloid cell leukemia sequence 1 (Mcl-1) for degradation, and small-interfering RNA (siRNA)-mediated knockdown of Noxa or p38(MAPK) inhibition restored levels of Mcl-1 and abolished apoptosis. Thus, the pro-apoptotic mechanisms orchestrated by p38(MAPK) in human keratinocytes in response to UVB involve an HIF-1/Noxa axis, which prompts the downregulation of anti-apoptotic Mcl-1, thereby favoring Bax-mediated mitochondrial apoptosis of UVB-damaged keratinocytes.
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Differential influence of anticancer treatments and angiogenesis on the seric titer of autoantibody used as tumor and metastasis biomarker.
Neoplasia
PUBLISHED: 02-03-2010
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Early detection of tumor-specific autoantibodies (auto-Abs) has the potential to be used for cancer screening and diagnosis. Whether auto-Ab may be useful to track metastatic progression or response to treatment is, however, largely unknown. To address these issues, the serological proteome was analyzed in an invasive but treatment-responsive mouse tumor model. Among 40 serum-reactive proteins identified by multiplex analysis, we chose to focus on glucose-regulated protein 78 (GRP78), a chaperone protein involved in the endoplasmic reticulum stress response. We first validated GRP78 as a protein overexpressed and mislocalized in tumor cells. We then documented that an increase in GRP78 auto-Ab titer preceded the detection of a palpable tumor mass, correlated with metastatic progression, and was influenced by the onset of tumor neovascularization. We also found that chemotherapy and radiotherapy, both leading to inhibition of tumor growth, oppositely influenced the anti-GRP78 immune response. Whereas radiation increased the concentration of GRP78 auto-Ab by three-fold, the auto-Ab titer was reduced in response to bolus or metronomic administration of cyclophosphamide. Finally, we established a decrease in auto-Ab-producing B lymphocytes in response to chemotherapy and the overexpression of GRP78 together with a strong immunoglobulin response in irradiated tumors. In conclusion, we identified GRP78 auto-Ab as an early marker of tumor and metastatic progressions. However, the multiple influences of anticancer treatments on the humoral immune system calls for caution when exploiting such auto-Ab as markers of the tumor response.
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NDRG1 and CRK-I/II are regulators of endothelial cell migration under Intermittent Hypoxia.
Angiogenesis
PUBLISHED: 07-15-2009
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Intermittent Hypoxia (IH) that develops in neovascularized solid tumours has been described to positively influence the tumour growth by modulating the behaviour of cancer cells as well as of endothelial cells. However, the molecular mechanisms regulated by IH still remain poorly understood. In this work, the effects of IH were investigated on endothelial cells by a proteomic approach. Protein abundance variations were studied using fluorescent 2D-Differential in Gel Electrophoresis (2D-DIGE). Amongst the proteins of which the abundance varied under IH, NDRG1 and CRK-I/II were identified by mass spectrometry. These proteins have already been described to influence cancer cell migration as well as the angiogenic processes in solid tumours. Since an increase in endothelial cell migration under IH was evidenced in our previous work, the involvement of NDRG1 and CRK-I/II proteins in endothelial cell migration under IH was determined by silencing the expression of both proteins using siRNA. The results revealed that NDRG1 and CRK-I/II are indeed regulators of endothelial cell migration under intermittent hypoxia: silencing of CRK-I/II resulted in an increase in endothelial cell migration, whereas the invalidation of NDRG1 decreased it. These results give news insight regarding the effects of IH on endothelial cell migration and hence on neoangiogenesis.
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Kinases as upstream regulators of the HIF system: their emerging potential as anti-cancer drug targets.
Curr. Pharm. Des.
PUBLISHED: 06-23-2009
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The hypoxia-inducible factor-1 (HIF-1) is a key regulator in the mammalian response to oxygen deficiency under both physiological and pathological conditions such as cancer. A number of studies indicated an association between tumor hypoxia, increased hypoxia-inducible factor (HIF-1alpha) levels and a poor prognosis. The HIF-1alpha regulation in response to hypoxia occurs primarily on the level of protein stability due to posttranslational hydroxylation. However, HIFalpha-subunits also respond to various growth factors, hormones, or cytokines under non-hypoxic conditions implicating the involvement of different kinase pathways in their regulation thereby increasing the interest in HIF-1alpha as a new drug target. Herein, we review current knowledge about phosphorylation-dependent HIF-1alpha regulation, HIF-1alpha protein-protein interactions and subcellular localization with emphasis on new therapeutic strategies targeting the HIF pathway.
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Hypoxia-induced decrease in p53 protein level and increase in c-jun DNA binding activity results in cancer cell resistance to etoposide.
Neoplasia
PUBLISHED: 04-15-2009
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Tumor hypoxia is one of the features of tumor microenvironment that contributes to chemoresistance in particular by cellular adaptations that modulate the apoptotic process. However, the mechanisms involved in this resistance still need deeper understanding. In this study, we investigated the involvement of four transcription factors, c-Myc, nuclear factor kappaB (NF-kappaB), p53, and c-jun/activator protein 1 (AP-1) in the hypoxia-induced resistance to etoposide in HepG2 cells. Whereas the profile of c-Myc and NF-kappaB activity did not fit the effect of hypoxia on caspase 3 activity, hypoxia decreased basal p53 abundance and DNA binding activity as well as p53 etoposide-induced activation. Short interfering RNA (siRNA) silencing evidenced that p53 was required for etoposide-induced apoptosis under normoxia. An inhibition of its activity under hypoxia could thus be responsible at least in part for the protection observed under hypoxic conditions. Moreover, p53 was found to induce the expression of Bak1. We showed that Bak1 was involved in the etoposide-induced apoptosis because Bak1 siRNA decreased it. Conversely, hypoxia increased c-jun DNA binding activity in the presence of etoposide. siRNA-mediated silencing of c-jun increased the responsiveness of cells to etoposide under hypoxia, as shown by an increase in caspase 3 activity and lactate dehydrogenase release. These effects occurred in a p53-independent manner. These data evidenced that hypoxia decreased the responsiveness of HepG2 cells to etoposide at least by two independent pathways involving p53 inhibition and c-jun activation.
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Transcriptional regulation of hypoxia-inducible factor 1alpha by HIPK2 suggests a novel mechanism to restrain tumor growth.
Biochim. Biophys. Acta
PUBLISHED: 04-02-2009
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HIPK2 has been implicated in restraining tumor progression by more than one mechanism, involving both its catalytic and transcriptional co-repressor functions. Starting from the finding that HIPK2 knockdown by RNA-interference (HIPK2i) induced significant up-regulation of HIF-1alpha mRNA and of its target VEGF in tumor cells, we evaluated the role of HIPK2 in transcriptional regulation of HIF-1alpha. We found that HIPK2 overexpression downmodulated both HIF-1alpha reporter activity and mRNA levels and showed that HIPK2 was bound in vivo to the HIF-1alpha promoter likely in a multiprotein co-repressor complex with histone deacetylase 1 (HDAC1). Thus, the HIF-1alpha promoter was strongly acetylated following HIPK2 knockdown. The HIF-1alpha-dependent VEGF transcription was evaluated by co-transfection of a dominant negative (DN) construct of HIF-1alpha that inhibited VEGF reporter activity induced by HIPK2 knockdown. HIF-1alpha and VEGF up-regulation in HIPK2i cells correlated with increased vascularity of tumor xenografts in vivo and tube formation in HUVEC in vitro. These findings provide the first evidence of HIPK2-mediated transcriptional regulation of HIF-1alpha that might play a critical role in VEGF expression.
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Identification of DH IC-2 as a HIF-1 independent protein involved in the adaptive response to hypoxia in tumor cells: A putative role in metastasis.
Biochim. Biophys. Acta
PUBLISHED: 03-24-2009
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The master regulator of the adaptive response to hypoxia is HIF-1. However, while some data show that HIF-1 can control more than 80% of the genes induced under hypoxia, other experiments clearly demonstrate that a part of the hypoxic response is independent of HIF-1. The goal of this study was to identify some of these HIF-1 independent factors and to investigate their functional role in the adaptation of tumor cells to hypoxia. We show that the cytoplasmic dynein intermediate chain 2 (DH IC-2), a component of an intracellular ATPase minus-end directed tubulin-based motile complex, was stabilized and post-translationally modified under hypoxia in a HIF-1 independent way. We identified this modification as a phosphorylation by protein kinase C, which is inhibited under hypoxia. In parallel, the migration of HepG2 cells was enhanced under hypoxia. Cell migration was also increased, to the same extent, by the invalidation of DH IC-2 using siRNA. Taken together, these results suggest that under hypoxia, a specific modification of DH IC-2 may modulate its activity, and in turn promote cell migration. These results are important to better understand cancer development since they highlight a HIF-1 independent mechanism, which may be involved in metastasis.
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Hypoxia regulates inflammatory gene expression in endothelial cells.
Exp. Cell Res.
PUBLISHED: 03-05-2009
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Hypoxia can activate the endothelium toward a pro-inflammatory phenotype and enhance leukocyte adhesion. This process is involved in pathological conditions such as vascular remodeling or ischemia-reperfusion injury. This study was aimed to obtain a global picture of the response of the endothelial cells to hypoxia with respect to inflammatory genes. To this purpose, we used a low density DNA microarray specifically designed to quantitate the expression of genes involved in the inflammatory pathways and a customized real-time PCR array. The expression of several pro-inflammatory genes known to be NF-kB target genes was decreased after the incubation of endothelial cells under hypoxia. In parallel, a decrease in the DNA binding activity of this transcription factor was observed. On the other hand, HIF-1 DNA binding activity was increased as well as the expression of several genes known to be regulated by this factor. Among them are several pro-inflammatory genes whose overexpression could account for the increase in leukocyte adhesion to the hypoxic endothelial cells. We concluded that hypoxia does not shift the endothelial cell phenotype to a more pro-inflammatory one probably because of a decrease in the expression of several cytokines. On the other hand, a clear response to hypoxia was observed with HIF-1 probably playing an important role in this process.
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Activation of the oxidative stress pathway by HIV-1 Vpr leads to induction of hypoxia-inducible factor 1alpha expression.
J. Biol. Chem.
PUBLISHED: 02-09-2009
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The detection of biomarkers of oxidative stress in brain tissue and cerebrospinal fluid of patients with human immunodeficiency virus, type 1 (HIV)-associated dementia indicates the involvement of stress pathways in the neuropathogenesis of AIDS. Although the biological importance of oxidative stress on events involved in AIDS neuropathogenesis and the HIV-1 proteins responsible for oxidative stress remain to be elucidated, our results point to the activation of hypoxia-inducible factor 1 (HIF-1) upon HIV-1 infection and its elevation in brain cells of AIDS patients with dementia. HIF-1 is a transcription factor that is responsive to oxygen. Under hypoxic conditions, HIF-1alpha becomes stable and translocates to the nucleus where it dimerizes with aryl hydrocarbon receptor nuclear translocator and modulates gene transcription. Activation of HIF-1 can also be mediated by the HIV-1 accessory protein Vpr. In addition, cellular components, including reactive oxygen species, contribute to the induction of HIF-1alpha. Our results show that Vpr induces reactive oxygen species by increasing H(2)O(2) production, which can contribute to HIF-1alpha accumulation. Interestingly, increased levels of HIF-1alpha stimulated HIV-1 gene transcription through HIF-1 association with HIV-1 long terminal repeat. These observations point to the existence of a positive feedback interplay between HIF-1alpha and Vpr and that, by inducing oxidative stress via activation of HIF-1, Vpr can induce HIV-1 gene expression and dysregulate multiple host cellular pathways.
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Intermittent hypoxia is an angiogenic inducer for endothelial cells: role of HIF-1.
Angiogenesis
PUBLISHED: 01-12-2009
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The presence of hypoxia in tumor and its role in promoting angiogenesis are well-established. Recently, in addition to chronic hypoxia, cycling or intermittent hypoxia has also been demonstrated. However, its role in inducing new blood vessel formation is less clear. This work is aimed to investigate whether intermittent hypoxia can induce a pro-angiogenic phenotype in endothelial cells, in vitro. We studied changes in the expression of genes involved in inflammation and angiogenesis under intermittent and chronic hypoxia. We evidenced genes specifically expressed under intermittent hypoxia, suggesting different cell responses induced by intermittent versus chronic hypoxia. An increase in the expression of pro-angiogenic and pro-inflammatory genes under intermittent hypoxia, translating a pro-angiogenic effect of intermittent hypoxia was detected. In parallel, we investigated the activity of three transcription factors known to be activated either under hypoxia or by reoxygenation: HIF-1, Nrf2, and NF-kappaB. HIF-1alpha stabilization and an increase in HIF-1 transcriptional activity were evidenced under intermittent hypoxia. On the other hand, NRF2 and NF-kappaB transcription factors were not activated. Finally, an increase in endothelial cell migration and in tubulogenesis in the course of hypoxia-reoxygenation cycles was evidenced, which was inhibited by HIF-1alpha siRNA. All together, these results demonstrate a clear pro-angiogenic effect of intermittent hypoxia.
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Hypoxia-induced modulation of apoptosis and BCL-2 family proteins in different cancer cell types.
PLoS ONE
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Hypoxia plays an important role in the resistance of tumour cells to chemotherapy. However, the exact mechanisms underlying this process are not well understood. Moreover, according to the cell lines, hypoxia differently influences cell death. The study of the effects of hypoxia on the apoptosis induced by 5 chemotherapeutic drugs in 7 cancer cell types showed that hypoxia generally inhibited the drug-induced apoptosis. In most cases, the effect of hypoxia was the same for all the drugs in one cell type. The expression profile of 93 genes involved in apoptosis as well as the protein level of BCL-2 family proteins were then investigated. In HepG2 cells that are strongly protected against cell death by hypoxia, hypoxia decreased the abundance of nearly all the pro-apoptotic BCL-2 family proteins while none of them are decreased in A549 cells that are not protected against cell death by hypoxia. In HepG2 cells, hypoxia decreased NOXA and BAD abundance and modified the electrophoretic mobility of BIM(EL). BIM and NOXA are important mediators of etoposide-induced cell death in HepG2 cells and the hypoxia-induced modification of these proteins abundance or post-translational modifications partly account for chemoresistance. Finally, the modulation of the abundance and/or of the post-translational modifications of most proteins of the BCL-2 family by hypoxia involves p53-dependent and -independent pathways and is cell type-dependent. A better understanding of these cell-to-cell variations is crucial in order to overcome hypoxia-induced resistance and to ameliorate cancer therapy.
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Guidelines for the use and interpretation of assays for monitoring autophagy.
Daniel J Klionsky, Fábio C Abdalla, Hagai Abeliovich, Robert T Abraham, Abraham Acevedo-Arozena, Khosrow Adeli, Lotta Agholme, Maria Agnello, Patrizia Agostinis, Julio A Aguirre-Ghiso, Hyung Jun Ahn, Ouardia Ait-Mohamed, Slimane Ait-Si-Ali, Takahiko Akematsu, Shizuo Akira, Hesham M Al-Younes, Munir A Al-Zeer, Matthew L Albert, Roger L Albin, Javier Alegre-Abarrategui, Maria Francesca Aleo, Mehrdad Alirezaei, Alexandru Almasan, Maylin Almonte-Becerril, Atsuo Amano, Ravi Amaravadi, Shoba Amarnath, Amal O Amer, Nathalie Andrieu-Abadie, Vellareddy Anantharam, David K Ann, Shailendra Anoopkumar-Dukie, Hiroshi Aoki, Nadezda Apostolova, Giuseppe Arancia, John P Aris, Katsuhiko Asanuma, Nana Y O Asare, Hisashi Ashida, Valerie Askanas, David S Askew, Patrick Auberger, Misuzu Baba, Steven K Backues, Eric H Baehrecke, Ben A Bahr, Xue-Yuan Bai, Yannick Bailly, Robert Baiocchi, Giulia Baldini, Walter Balduini, Andrea Ballabio, Bruce A Bamber, Edward T W Bampton, Gábor Bánhegyi, Clinton R Bartholomew, Diane C Bassham, Robert C Bast, Henri Batoko, Boon-Huat Bay, Isabelle Beau, Daniel M Béchet, Thomas J Begley, Christian Behl, Christian Behrends, Soumeya Bekri, Bryan Bellaire, Linda J Bendall, Luca Benetti, Laura Berliocchi, Henri Bernardi, Francesca Bernassola, Sébastien Besteiro, Ingrid Bhatia-Kiššová, Xiaoning Bi, Martine Biard-Piechaczyk, Janice S Blum, Lawrence H Boise, Paolo Bonaldo, David L Boone, Beat C Bornhauser, Karina R Bortoluci, Ioannis Bossis, Fréderic Bost, Jean-Pierre Bourquin, Patricia Boya, Michaël Boyer-Guittaut, Peter V Bozhkov, Nathan R Brady, Claudio Brancolini, Andreas Brech, Jay E Brenman, Ana Brennand, Emery H Bresnick, Patrick Brest, Dave Bridges, Molly L Bristol, Paul S Brookes, Eric J Brown, John H Brumell, Nicola Brunetti-Pierri, Ulf T Brunk, Dennis E Bulman, Scott J Bultman, Geert Bultynck, Lena F Burbulla, Wilfried Bursch, Jonathan P Butchar, Wanda Buzgariu, Sérgio P Bydlowski, Ken Cadwell, Monika Cahova, Dongsheng Cai, Jiyang Cai, Qian Cai, Bruno Calabretta, Javier Calvo-Garrido, Nadine Camougrand, Michelangelo Campanella, Jenny Campos-Salinas, Eleonora Candi, Lizhi Cao, Allan B Caplan, Simon R Carding, Sandra M Cardoso, Jennifer S Carew, Cathleen R Carlin, Virginie Carmignac, Leticia A M Carneiro, Serena Carra, Rosario A Caruso, Giorgio Casari, Caty Casas, Roberta Castino, Eduardo Cebollero, Francesco Cecconi, Jean Celli, Hassan Chaachouay, Han-Jung Chae, Chee-Yin Chai, David C Chan, Edmond Y Chan, Raymond Chuen-Chung Chang, Chi-Ming Che, Ching-Chow Chen, Guang-Chao Chen, Guo-Qiang Chen, Min Chen, Quan Chen, Steve S-L Chen, WenLi Chen, Xi Chen, Xiangmei Chen, Xiequn Chen, Ye-Guang Chen, Yingyu Chen, Yongqiang Chen, Yu-Jen Chen, Zhixiang Chen, Alan Cheng, Christopher H K Cheng, Yan Cheng, Heesun Cheong, Jae-Ho Cheong, Sara Cherry, Russ Chess-Williams, Zelda H Cheung, Eric Chevet, Hui-Ling Chiang, Roberto Chiarelli, Tomoki Chiba, Lih-Shen Chin, Shih-Hwa Chiou, Francis V Chisari, Chi Hin Cho, Dong-Hyung Cho, Augustine M K Choi, DooSeok Choi, Kyeong Sook Choi, Mary E Choi, Salem Chouaib, Divaker Choubey, Vinay Choubey, Charleen T Chu, Tsung-Hsien Chuang, Sheau-Huei Chueh, Taehoon Chun, Yong-Joon Chwae, Mee-Len Chye, Roberto Ciarcia, Maria R Ciriolo, Michael J Clague, Robert S B Clark, Peter G H Clarke, Robert Clarke, Patrice Codogno, Hilary A Coller, María I Colombo, Sergio Comincini, Maria Condello, Fabrizio Condorelli, Mark R Cookson, Graham H Coombs, Isabelle Coppens, Ramón Corbalán, Pascale Cossart, Paola Costelli, Safia Costes, Ana Coto-Montes, Eduardo Couve, Fraser P Coxon, James M Cregg, José L Crespo, Marianne J Cronjé, Ana Maria Cuervo, Joseph J Cullen, Mark J Czaja, Marcello D'Amelio, Arlette Darfeuille-Michaud, Lester M Davids, Faith E Davies, Massimo De Felici, John F de Groot, Cornelis A M de Haan, Luisa De Martino, Angelo De Milito, Vincenzo De Tata, Jayanta Debnath, Alexei Degterev, Benjamin Dehay, Lea M D Delbridge, Francesca Demarchi, Yi Zhen Deng, Jörn Dengjel, Paul Dent, Donna Denton, Vojo Deretic, Shyamal D Desai, Rodney J Devenish, Mario Di Gioacchino, Gilbert Di Paolo, Chiara Di Pietro, Guillermo Díaz-Araya, Inés Díaz-Laviada, Maria T Diaz-Meco, Javier Diaz-Nido, Ivan Dikic, Savithramma P Dinesh-Kumar, Wen-Xing Ding, Clark W Distelhorst, Abhinav Diwan, Mojgan Djavaheri-Mergny, Svetlana Dokudovskaya, Zheng Dong, Frank C Dorsey, Victor Dosenko, James J Dowling, Stephen Doxsey, Marlène Dreux, Mark E Drew, Qiuhong Duan, Michel A Duchosal, Karen Duff, Isabelle Dugail, Madeleine Durbeej, Michael Duszenko, Charles L Edelstein, Aimee L Edinger, Gustavo Egea, Ludwig Eichinger, N Tony Eissa, Suhendan Ekmekcioglu, Wafik S El-Deiry, Zvulun Elazar, Mohamed Elgendy, Lisa M Ellerby, Kai Er Eng, Anna-Mart Engelbrecht, Simone Engelender, Jekaterina Erenpreisa, Ricardo Escalante, Audrey Esclatine, Eeva-Liisa Eskelinen, Lucile Espert, Virginia Espina, Huizhou Fan, Jia Fan, Qi-Wen Fan, Zhen Fan, Shengyun Fang, Yongqi Fang, Manolis Fanto, Alessandro Fanzani, Thomas Farkas, Jean-Claude Farré, Mathias Faure, Marcus Fechheimer, Carl G Feng, Jian Feng, Qili Feng, Youji Feng, László Fésüs, Ralph Feuer, Maria E Figueiredo-Pereira, Gian Maria Fimia, Diane C Fingar, Steven Finkbeiner, Toren Finkel, Kim D Finley, Filomena Fiorito, Edward A Fisher, Paul B Fisher, Marc Flajolet, Maria L Florez-McClure, Salvatore Florio, Edward A Fon, Francesco Fornai, Franco Fortunato, Rati Fotedar, Daniel H Fowler, Howard S Fox, Rodrigo Franco, Lisa B Frankel, Marc Fransen, José M Fuentes, Juan Fueyo, Jun Fujii, Kozo Fujisaki, Eriko Fujita, Mitsunori Fukuda, Ruth H Furukawa, Matthias Gaestel, Philippe Gailly, Malgorzata Gajewska, Brigitte Galliot, Vincent Galy, Subramaniam Ganesh, Barry Ganetzky, Ian G Ganley, Fen-Biao Gao, George F Gao, Jinming Gao, Lorena Garcia, Guillermo Garcia-Manero, Mikel Garcia-Marcos, Marjan Garmyn, Andrei L Gartel, Evelina Gatti, Mathias Gautel, Thomas R Gawriluk, Matthew E Gegg, Jiefei Geng, Marc Germain, Jason E Gestwicki, David A Gewirtz, Saeid Ghavami, Pradipta Ghosh, Anna M Giammarioli, Alexandra N Giatromanolaki, Spencer B Gibson, Robert W Gilkerson, Michael L Ginger, Henry N Ginsberg, Jakub Golab, Michael S Goligorsky, Pierre Golstein, Candelaria Gomez-Manzano, Ebru Goncu, Céline Gongora, Claudio D Gonzalez, Ramon Gonzalez, Cristina González-Estévez, Rosa Ana González-Polo, Elena Gonzalez-Rey, Nikolai V Gorbunov, Sharon Gorski, Sandro Goruppi, Roberta A Gottlieb, Devrim Gozuacik, Giovanna Elvira Granato, Gary D Grant, Kim N Green, Aleš Gregorc, Frédéric Gros, Charles Grose, Thomas W Grunt, Philippe Gual, Jun-Lin Guan, Kun-Liang Guan, Sylvie M Guichard, Anna S Gukovskaya, Ilya Gukovsky, Jan Gunst, Asa B Gustafsson, Andrew J Halayko, Amber N Hale, Sandra K Halonen, Maho Hamasaki, Feng Han, Ting Han, Michael K Hancock, Malene Hansen, Hisashi Harada, Masaru Harada, Stefan E Hardt, J Wade Harper, Adrian L Harris, James Harris, Steven D Harris, Makoto Hashimoto, Jeffrey A Haspel, Shin-Ichiro Hayashi, Lori A Hazelhurst, Congcong He, You-Wen He, Marie-Josee Hebert, Kim A Heidenreich, Miep H Helfrich, Gudmundur V Helgason, Elizabeth P Henske, Brian Herman, Paul K Herman, Claudio Hetz, Sabine Hilfiker, Joseph A Hill, Lynne J Hocking, Paul Hofman, Thomas G Hofmann, Jörg Höhfeld, Tessa L Holyoake, Ming-Huang Hong, David A Hood, Gökhan S Hotamisligil, Ewout J Houwerzijl, Maria Høyer-Hansen, Bingren Hu, Chien-An A Hu, Hong-Ming Hu, Ya Hua, Canhua Huang, Ju Huang, Shengbing Huang, Wei-Pang Huang, Tobias B Huber, Won-Ki Huh, Tai-Ho Hung, Ted R Hupp, Gang Min Hur, James B Hurley, Sabah N A Hussain, Patrick J Hussey, Jung Jin Hwang, Seungmin Hwang, Atsuhiro Ichihara, Shirin Ilkhanizadeh, Ken Inoki, Takeshi Into, Valentina Iovane, Juan L Iovanna, Nancy Y Ip, Yoshitaka Isaka, Hiroyuki Ishida, Ciro Isidoro, Ken-Ichi Isobe, Akiko Iwasaki, Marta Izquierdo, Yotaro Izumi, Panu M Jaakkola, Marja Jäättelä, George R Jackson, William T Jackson, Bassam Janji, Marina Jendrach, Ju-Hong Jeon, Eui-Bae Jeung, Hong Jiang, Hongchi Jiang, Jean X Jiang, Ming Jiang, Qing Jiang, Xuejun Jiang, Alberto Jiménez, Meiyan Jin, Shengkan Jin, Cheol O Joe, Terje Johansen, Daniel E Johnson, Gail V W Johnson, Nicola L Jones, Bertrand Joseph, Suresh K Joseph, Annie M Joubert, Gábor Juhász, Lucienne Juillerat-Jeanneret, Chang Hwa Jung, Yong-Keun Jung, Kai Kaarniranta, Allen Kaasik, Tomohiro Kabuta, Motoni Kadowaki, Katarina Kågedal, Yoshiaki Kamada, Vitaliy O Kaminskyy, Harm H Kampinga, Hiromitsu Kanamori, Chanhee Kang, Khong Bee Kang, Kwang Il Kang, Rui Kang, Yoon-A Kang, Tomotake Kanki, Thirumala-Devi Kanneganti, Haruo Kanno, Anumantha G Kanthasamy, Arthi Kanthasamy, Vassiliki Karantza, Gur P Kaushal, Susmita Kaushik, Yoshinori Kawazoe, Po-Yuan Ke, John H Kehrl, Ameeta Kelekar, Claus Kerkhoff, David H Kessel, Hany Khalil, Jan A K W Kiel, Amy A Kiger, Akio Kihara, Deok Ryong Kim, Do-Hyung Kim, Dong-Hou Kim, Eun-Kyoung Kim, Hyung-Ryong Kim, Jae-Sung Kim, Jeong Hun Kim, Jin Cheon Kim, John K Kim, Peter K Kim, Seong Who Kim, Yong-Sun Kim, Yonghyun Kim, Adi Kimchi, Alec C Kimmelman, Jason S King, Timothy J Kinsella, Vladimir Kirkin, Lorrie A Kirshenbaum, Katsuhiko Kitamoto, Kaio Kitazato, Ludger Klein, Walter T Klimecki, Jochen Klucken, Erwin Knecht, Ben C B Ko, Jan C Koch, Hiroshi Koga, Jae-Young Koh, Young Ho Koh, Masato Koike, Masaaki Komatsu, Eiki Kominami, Hee Jeong Kong, Wei-jia Kong, Viktor I Korolchuk, Yaichiro Kotake, Michael I Koukourakis, Juan B Kouri Flores, Attila L Kovács, Claudine Kraft, Dimitri Krainc, Helmut Krämer, Carole Kretz-Remy, Anna M Krichevsky, Guido Kroemer, Rejko Krüger, Oleg Krut, Nicholas T Ktistakis, Chia-Yi Kuan, Róza Kucharczyk, Ashok Kumar, Raj Kumar, Sharad Kumar, Mondira Kundu, Hsing-Jien Kung, Tino Kurz, Ho Jeong Kwon, Albert R La Spada, Frank Lafont, Trond Lamark, Jacques Landry, Jon D Lane, Pierre Lapaquette, Jocelyn F Laporte, Lajos László, Sergio Lavandero, Josée N Lavoie, Robert Layfield, Pedro A Lazo, Weidong Le, Laurent Le Cam, Daniel J Ledbetter, Alvin J X Lee, Byung-Wan Lee, Gyun Min Lee, Jongdae Lee, Ju-Hyun Lee, Michael Lee, Myung-Shik Lee, Sug Hyung Lee, Christiaan Leeuwenburgh, Patrick Legembre, Renaud Legouis, Michael Lehmann, Huan-Yao Lei, Qun-Ying Lei, David A Leib, José Leiro, John J Lemasters, Antoinette Lemoine, Maciej S Lesniak, Dina Lev, Victor V Levenson, Beth Levine, Efrat Levy, Faqiang Li, Jun-lin Li, Lian Li, Sheng Li, Weijie Li, Xue-Jun Li, Yan-Bo Li, Yi-Ping Li, Chengyu Liang, Qiangrong Liang, Yung-Feng Liao, Pawel P Liberski, Andrew Lieberman, Hyunjung J Lim, Kah-Leong Lim, Kyu Lim, Chiou-Feng Lin, Fu-Cheng Lin, Jian Lin, Jiandie D Lin, Kui Lin, Wan-Wan Lin, Weei-Chin Lin, Yi-Ling Lin, Rafael Linden, Paul Lingor, Jennifer Lippincott-Schwartz, Michael P Lisanti, Paloma B Liton, Bo Liu, Chun-Feng Liu, Kaiyu Liu, Leyuan Liu, Qiong A Liu, Wei Liu, Young-Chau Liu, Yule Liu, Richard A Lockshin, Chun-Nam Lok, Sagar Lonial, Benjamin Loos, Gabriel Lopez-Berestein, Carlos Lopez-Otin, Laura Lossi, Michael T Lotze, Péter Low, Binfeng Lu, Bingwei Lu, Bo Lu, Zhen Lu, Fredéric Luciano, Nicholas W Lukacs, Anders H Lund, Melinda A Lynch-Day, Yong Ma, Fernando Macian, Jeff P MacKeigan, Kay F Macleod, Frank Madeo, Luigi Maiuri, Maria Chiara Maiuri, Davide Malagoli, May Christine V Malicdan, Walter Malorni, Na Man, Eva-Maria Mandelkow, Stéphen Manon, Irena Manov, Kai Mao, Xiang Mao, Zixu Mao, Philippe Marambaud, Daniela Marazziti, Yves L Marcel, Katie Marchbank, Piero Marchetti, Stefan J Marciniak, Mateus Marcondes, Mohsen Mardi, Gabriella Marfè, Guillermo Mariño, Maria Markaki, Mark R Marten, Seamus J Martin, Camille Martinand-Mari, Wim Martinet, Marta Martinez-Vicente, Matilde Masini, Paola Matarrese, Saburo Matsuo, Raffaele Matteoni, Andreas Mayer, Nathalie M Mazure, David J McConkey, Melanie J McConnell, Catherine McDermott, Christine McDonald, Gerald M McInerney, Sharon L McKenna, BethAnn McLaughlin, Pamela J McLean, Christopher R McMaster, G Angus McQuibban, Alfred J Meijer, Miriam H Meisler, Alicia Meléndez, Thomas J Melia, Gerry Melino, Maria A Mena, Javier A Menendez, Rubem F S Menna-Barreto, Manoj B Menon, Fiona M Menzies, Carol A Mercer, Adalberto Merighi, Diane E Merry, Stefania Meschini, Christian G Meyer, Thomas F Meyer, Chao-Yu Miao, Jun-Ying Miao, Paul A M Michels, Carine Michiels, Dalibor Mijaljica, Ana Milojkovic, Saverio Minucci, Clelia Miracco, Cindy K Miranti, Ioannis Mitroulis, Keisuke Miyazawa, Noboru Mizushima, Baharia Mograbi, Simin Mohseni, Xavier Molero, Bertrand Mollereau, Faustino Mollinedo, Takashi Momoi, Iryna Monastyrska, Martha M Monick, Mervyn J Monteiro, Michael N Moore, Rodrigo Mora, Kevin Moreau, Paula I Moreira, Yuji Moriyasu, Jorge Moscat, Serge Mostowy, Jeremy C Mottram, Tomasz Motyl, Charbel E-H Moussa, Sylke Müller, Sylviane Muller, Karl Münger, Christian Münz, Leon O Murphy, Maureen E Murphy, Antonio Musarò, Indira Mysorekar, Eiichiro Nagata, Kazuhiro Nagata, Aimable Nahimana, Usha Nair, Toshiyuki Nakagawa, Kiichi Nakahira, Hiroyasu Nakano, Hitoshi Nakatogawa, Meera Nanjundan, Naweed I Naqvi, Derek P Narendra, Masashi Narita, Miguel Navarro, Steffan T Nawrocki, Taras Y Nazarko, Andriy Nemchenko, Mihai G Netea, Thomas P Neufeld, Paul A Ney, Ioannis P Nezis, Huu Phuc Nguyen, Daotai Nie, Ichizo Nishino, Corey Nislow, Ralph A Nixon, Takeshi Noda, Angelika A Noegel, Anna Nogalska, Satoru Noguchi, Lucia Notterpek, Ivana Novak, Tomoyoshi Nozaki, Nobuyuki Nukina, Thorsten Nürnberger, Beat Nyfeler, Keisuke Obara, Terry D Oberley, Salvatore Oddo, Michinaga Ogawa, Toya Ohashi, Koji Okamoto, Nancy L Oleinick, F Javier Oliver, Laura J Olsen, Stefan Olsson, Onya Opota, Timothy F Osborne, Gary K Ostrander, Kinya Otsu, Jing-hsiung James Ou, Mireille Ouimet, Michael Overholtzer, Bulent Ozpolat, Paolo Paganetti, Ugo Pagnini, Nicolas Pallet, Glen E Palmer, Camilla Palumbo, Tianhong Pan, Theocharis Panaretakis, Udai Bhan Pandey, Zuzana Papackova, Issidora Papassideri, Irmgard Paris, Junsoo Park, Ohkmae K Park, Jan B Parys, Katherine R Parzych, Susann Patschan, Cam Patterson, Sophie Pattingre, John M Pawelek, Jianxin Peng, David H Perlmutter, Ida Perrotta, George Perry, Shazib Pervaiz, Matthias Peter, Godefridus J Peters, Morten Petersen, Goran Petrovski, James M Phang, Mauro Piacentini, Philippe Pierre, Valérie Pierrefite-Carle, Gérard Pierron, Ronit Pinkas-Kramarski, Antonio Piras, Natik Piri, Leonidas C Platanias, Stefanie Pöggeler, Marc Poirot, Angelo Poletti, Christian Poüs, Mercedes Pozuelo-Rubio, Mette Prætorius-Ibba, Anil Prasad, Mark Prescott, Muriel Priault, Nathalie Produit-Zengaffinen, Ann Progulske-Fox, Tassula Proikas-Cezanne, Serge Przedborski, Karin Przyklenk, Rosa Puertollano, Julien Puyal, Shu-Bing Qian, Liang Qin, Zheng-Hong Qin, Susan E Quaggin, Nina Raben, Hannah Rabinowich, Simon W Rabkin, Irfan Rahman, Abdelhaq Rami, Georg Ramm, Glenn Randall, Felix Randow, V Ashutosh Rao, Jeffrey C Rathmell, Brinda Ravikumar, Swapan K Ray, Bruce H Reed, John C Reed, Fulvio Reggiori, Anne Regnier-Vigouroux, Andreas S Reichert, John J Reiners, Russel J Reiter, Jun Ren, Jose L Revuelta, Christopher J Rhodes, Konstantinos Ritis, Elizete Rizzo, Jeffrey Robbins, Michel Roberge, Hernan Roca, Maria C Roccheri, Stéphane Rocchi, H Peter Rodemann, Santiago Rodríguez de Córdoba, Bärbel Rohrer, Igor B Roninson, Kirill Rosen, Magdalena M Rost-Roszkowska, Mustapha Rouis, Kasper M A Rouschop, Francesca Rovetta, Brian P Rubin, David C Rubinsztein, Klaus Ruckdeschel, Edmund B Rucker, Assaf Rudich, Emil Rudolf, Nelson Ruiz-Opazo, Rossella Russo, Tor Erik Rusten, Kevin M Ryan, Stefan W Ryter, David M Sabatini, Junichi Sadoshima, Tapas Saha, Tatsuya Saitoh, Hiroshi Sakagami, Yasuyoshi Sakai, Ghasem Hoseini Salekdeh, Paolo Salomoni, Paul M Salvaterra, Guy Salvesen, Rosa Salvioli, Anthony M J Sanchez, José A Sánchez-Alcázar, Ricardo Sánchez-Prieto, Marco Sandri, Uma Sankar, Poonam Sansanwal, Laura Santambrogio, Shweta Saran, Sovan Sarkar, Minnie Sarwal, Chihiro Sasakawa, Ausra Sasnauskiene, Miklós Sass, Ken Sato, Miyuki Sato, Anthony H V Schapira, Michael Scharl, Hermann M Schätzl, Wiep Scheper, Stefano Schiaffino, Claudio Schneider, Marion E Schneider, Regine Schneider-Stock, Patricia V Schoenlein, Daniel F Schorderet, Christoph Schüller, Gary K Schwartz, Luca Scorrano, Linda Sealy, Per O Seglen, Juan Segura-Aguilar, Iban Seiliez, Oleksandr Seleverstov, Christian Sell, Jong Bok Seo, Duska Separovic, Vijayasaradhi Setaluri, Takao Setoguchi, Carmine Settembre, John J Shacka, Mala Shanmugam, Irving M Shapiro, Eitan Shaulian, Reuben J Shaw, James H Shelhamer, Han-Ming Shen, Wei-Chiang Shen, Zu-Hang Sheng, Yang Shi, Kenichi Shibuya, Yoshihiro Shidoji, Jeng-Jer Shieh, Chwen-Ming Shih, Yohta Shimada, Shigeomi Shimizu, Takahiro Shintani, Orian S Shirihai, Gordon C Shore, Andriy A Sibirny, Stan B Sidhu, Beata Sikorska, Elaine C M Silva-Zacarin, Alison Simmons, Anna Katharina Simon, Hans-Uwe Simon, Cristiano Simone, Anne Simonsen, David A Sinclair, Rajat Singh, Debasish Sinha, Frank A Sinicrope, Agnieszka Sirko, Parco M Siu, Efthimios Sivridis, Vojtech Skop, Vladimir P Skulachev, Ruth S Slack, Soraya S Smaili, Duncan R Smith, María S Soengas, Thierry Soldati, Xueqin Song, Anil K Sood, Tuck Wah Soong, Federica Sotgia, Stephen A Spector, Claudia D Spies, Wolfdieter Springer, Srinivasa M Srinivasula, Leonidas Stefanis, Joan S Steffan, Ruediger Stendel, Harald Stenmark, Anastasis Stephanou, Stephan T Stern, Cinthya Sternberg, Björn Stork, Peter Stralfors, Carlos S Subauste, Xinbing Sui, David Sulzer, Jiaren Sun, Shi-Yong Sun, Zhi-Jun Sun, Joseph J Y Sung, Kuninori Suzuki, Toshihiko Suzuki, Michele S Swanson, Charles Swanton, Sean T Sweeney, Lai-King Sy, Gyorgy Szabadkai, Ira Tabas, Heinrich Taegtmeyer, Marco Tafani, Krisztina Takács-Vellai, Yoshitaka Takano, Kaoru Takegawa, Genzou Takemura, Fumihiko Takeshita, Nicholas J Talbot, Kevin S W Tan, Keiji Tanaka, Kozo Tanaka, Daolin Tang, Dingzhong Tang, Isei Tanida, Bakhos A Tannous, Nektarios Tavernarakis, Graham S Taylor, Gregory A Taylor, J Paul Taylor, Lance S Terada, Alexei Terman, Gianluca Tettamanti, Karin Thevissen, Craig B Thompson, Andrew Thorburn, Michael Thumm, Fengfeng Tian, Yuan Tian, Glauco Tocchini-Valentini, Aviva M Tolkovsky, Yasuhiko Tomino, Lars Tönges, Sharon A Tooze, Cathy Tournier, John Tower, Roberto Towns, Vladimir Trajkovic, Leonardo H Travassos, Ting-Fen Tsai, Mario P Tschan, Takeshi Tsubata, Allan Tsung, Boris Turk, Lorianne S Turner, Suresh C Tyagi, Yasuo Uchiyama, Takashi Ueno, Midori Umekawa, Rika Umemiya-Shirafuji, Vivek K Unni, Maria I Vaccaro, Enza Maria Valente, Greet Van den Berghe, Ida J van der Klei, Wouter van Doorn, Linda F van Dyk, Marjolein van Egmond, Leo A van Grunsven, Peter Vandenabeele, Wim P Vandenberghe, Ilse Vanhorebeek, Eva C Vaquero, Guillermo Velasco, Tibor Vellai, Jose Miguel Vicencio, Richard D Vierstra, Miquel Vila, Cécile Vindis, Giampietro Viola, Maria Teresa Viscomi, Olga V Voitsekhovskaja, Clarissa von Haefen, Marcela Votruba, Keiji Wada, Richard Wade-Martins, Cheryl L Walker, Craig M Walsh, Jochen Walter, Xiang-Bo Wan, Aimin Wang, Chenguang Wang, Dawei Wang, Fan Wang, Fen Wang, Guanghui Wang, Haichao Wang, Hong-Gang Wang, Horng-Dar Wang, Jin Wang, Ke Wang, Mei Wang, Richard C Wang, Xinglong Wang, Xuejun Wang, Ying-Jan Wang, Yipeng Wang, Zhen Wang, Zhigang Charles Wang, Zhinong Wang, Derick G Wansink, Diane M Ward, Hirotaka Watada, Sarah L Waters, Paul Webster, Lixin Wei, Conrad C Weihl, William A Weiss, Scott M Welford, Long-Ping Wen, Caroline A Whitehouse, J Lindsay Whitton, Alexander J Whitworth, Tom Wileman, John W Wiley, Simon Wilkinson, Dieter Willbold, Roger L Williams, Peter R Williamson, Bradly G Wouters, Chenghan Wu, Dao-Cheng Wu, William K K Wu, Andreas Wyttenbach, Ramnik J Xavier, Zhijun Xi, Pu Xia, Gengfu Xiao, Zhiping Xie, Zhonglin Xie, Da-zhi Xu, Jianzhen Xu, Liang Xu, Xiaolei Xu, Ai Yamamoto, Akitsugu Yamamoto, Shunhei Yamashina, Michiaki Yamashita, Xianghua Yan, Mitsuhiro Yanagida, Dun-Sheng Yang, Elizabeth Yang, Jin-Ming Yang, Shi Yu Yang, Wannian Yang, Wei Yuan Yang, Zhifen Yang, Meng-Chao Yao, Tso-Pang Yao, Behzad Yeganeh, Wei-Lien Yen, Jia-Jing Yin, Xiao-Ming Yin, Ook-Joon Yoo, Gyesoon Yoon, Seung-Yong Yoon, Tomohiro Yorimitsu, Yuko Yoshikawa, Tamotsu Yoshimori, Kohki Yoshimoto, Ho Jin You, Richard J Youle, Anas Younes, Li Yu, Long Yu, Seong-Woon Yu, Wai Haung Yu, Zhi-Min Yuan, Zhenyu Yue, Cheol-Heui Yun, Michisuke Yuzaki, Olga Zabirnyk, Elaine Silva-Zacarin, David Zacks, Eldad Zacksenhaus, Nadia Zaffaroni, Zahra Zakeri, Herbert J Zeh, Scott O Zeitlin, Hong Zhang, Hui-Ling Zhang, Jianhua Zhang, Jing-Pu Zhang, Lin Zhang, Long Zhang, Ming-Yong Zhang, Xu Dong Zhang, Mantong Zhao, Yi-Fang Zhao, Ying Zhao, Zhizhuang J Zhao, Xiaoxiang Zheng, Boris Zhivotovsky, Qing Zhong, Cong-Zhao Zhou, Changlian Zhu, Wei-Guo Zhu, Xiao-feng Zhu, Xiongwei Zhu, Yuangang Zhu, Teresa Zoladek, Wei-Xing Zong, Antonio Zorzano, Jürgen Zschocke, Brian Zuckerbraun.
Autophagy
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In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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TMEM45A is essential for hypoxia-induced chemoresistance in breast and liver cancer cells.
BMC Cancer
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Hypoxia is a common characteristic of solid tumors associated with reduced response to radio- and chemotherapy, therefore increasing the probability of tumor recurrence. The aim of this study was to identify new mechanisms responsible for hypoxia-induced resistance in breast cancer cells.
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Targeting the lactate transporter MCT1 in endothelial cells inhibits lactate-induced HIF-1 activation and tumor angiogenesis.
PLoS ONE
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Switching to a glycolytic metabolism is a rapid adaptation of tumor cells to hypoxia. Although this metabolic conversion may primarily represent a rescue pathway to meet the bioenergetic and biosynthetic demands of proliferating tumor cells, it also creates a gradient of lactate that mirrors the gradient of oxygen in tumors. More than a metabolic waste, the lactate anion is known to participate to cancer aggressiveness, in part through activation of the hypoxia-inducible factor-1 (HIF-1) pathway in tumor cells. Whether lactate may also directly favor HIF-1 activation in endothelial cells (ECs) thereby offering a new druggable option to block angiogenesis is however an unanswered question. In this study, we therefore focused on the role in ECs of monocarboxylate transporter 1 (MCT1) that we previously identified to be the main facilitator of lactate uptake in cancer cells. We found that blockade of lactate influx into ECs led to inhibition of HIF-1-dependent angiogenesis. Our demonstration is based on the unprecedented characterization of lactate-induced HIF-1 activation in normoxic ECs and the consecutive increase in vascular endothelial growth factor receptor 2 (VEGFR2) and basic fibroblast growth factor (bFGF) expression. Furthermore, using a variety of functional assays including endothelial cell migration and tubulogenesis together with in vivo imaging of tumor angiogenesis through intravital microscopy and immunohistochemistry, we documented that MCT1 blockers could act as bona fide HIF-1 inhibitors leading to anti-angiogenic effects. Together with the previous demonstration of MCT1 being a key regulator of lactate exchange between tumor cells, the current study identifies MCT1 inhibition as a therapeutic modality combining antimetabolic and anti-angiogenic activities.
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