bluuebunny/crossref_metadata_2025 huggingface dataset:
Small GTPase RhoE/Rnd3 Is a Critical Regulator of Notch1 Signaling
Authors: Zhu Zehua , Todorova Kristina , Lee Kevin K. , Wang Jun , Kwon Eunjeong , Kehayov Ivan , Kim Hyung-Gu , Kolev Vihren , Dotto G. Paolo , Lee Sam W. , Mandinova Anna
Published: February 2014

Aberrations of Notch signaling have been implicated in a variety of human cancers. Oncogenic mutations in NOTCH1 are common in human T-cell leukemia and lymphomas. However, loss-of-function somatic mutations in NOTCH1 arising in solid tumors imply a tumor suppressor function, which highlights the need to understand Notch signaling more completely. Here, we describe the small GTPase RhoE/Rnd3 as a downstream mediator of Notch signaling in squamous cell carcinomas (SCC) that arise in skin epithelia. RhoE is a transcriptional target of activated Notch1, which is attenuated broadly in SCC cells. RhoE depletion suppresses Notch1-mediated signaling in vitro, rendering primary keratinocytes resistant to Notch1-mediated differentiation and thereby favoring a proliferative cell fate. Mechanistic investigations indicated that RhoE controls a key step in Notch1 signaling by mediating nuclear translocation of the activated portion of Notch1 (N1IC) through interaction with importins. Our results define RhoE as a Notch1 target that is essential for recruitment of N1IC to the promoters of Notch1 target genes, establishing a regulatory feedback loop in Notch1 signaling. This molecular circuitry may inform distinct cell fate decisions to Notch1 in epithelial tissues, where carcinomas such as SCC arise. Cancer Res; 74(7); 2082–93. ©2014 AACR.
NOTCH3 Signaling Regulates MUSASHI-1 Expression in Metastatic Colorectal Cancer Cells
Authors: Pastò Anna , Serafin Valentina , Pilotto Giorgia , Lago Claudia , Bellio Chiara , Trusolino Livio , Bertotti Andrea , Hoey Timothy , Plateroti Michelina , Esposito Giovanni , Pinazza Marica , Agostini Marco , Nitti Donato , Amadori Alberto , Indraccolo Stefano
Published: February 2014

MUSASHI-1 (MSI-1) is a well-established stem cell marker in both normal and malignant colon cells and it acts by positively regulating the NOTCH pathway through inactivation of NUMB, a NOTCH signaling repressor. To date, the mechanisms of regulation of MSI-1 levels remain largely unknown. Here, we investigated the regulation of MSI-1 by NOTCH signaling in colorectal cancer cell lines and in primary cultures of colorectal cancer metastases. Stimulation by the NOTCH ligand DLL4 was associated with an increase of MSI-1 mRNA and protein levels, and this phenomenon was prevented by the addition of an antibody neutralizing NOTCH2/3 but not NOTCH1. Moreover, forced expression of activated NOTCH3 increased MSI-1 levels, whereas silencing of NOTCH3 by short hairpin RNA reduced MSI-1 levels in both colorectal cancer cells and CRC tumor xenografts. Consistent with these findings, enforced NOTCH3 expression or stimulation by DLL4 increased levels of activated NOTCH1 in colorectal cell lines. Finally, treatment of colorectal cancer cells with anti-NOTCH2/3 antibody increased NUMB protein while significantly reducing formation of tumor cell spheroids. This novel feed-forward circuit involving DLL4, NOTCH3, MSI-1, NUMB, and NOTCH1 may be relevant for regulation of NOTCH signaling in physiologic processes as well as in tumor development. With regard to therapeutic implications, NOTCH3-specific drugs could represent a valuable strategy to limit NOTCH signaling in the context of colorectal cancers overexpressing this receptor. Cancer Res; 74(7); 2106–18. ©2014 AACR.
IL-17A Produced by γδ T Cells Promotes Tumor Growth in Hepatocellular Carcinoma
Authors: Ma Shoubao , Cheng Qiao , Cai Yifeng , Gong Huanle , Wu Yan , Yu Xiao , Shi Liyun , Wu Depei , Dong Chen , Liu Haiyan
Published: February 2014

Interleukin (IL)-17A is expressed in the tumor microenvironment where it appears to contribute to tumor development, but its precise role in tumor immunity remains controversial. Here, we report mouse genetic evidence that IL-17A is critical for tumor growth. IL-17A–deficient mice exhibited reduced tumor growth, whereas systemic administration of recombinant mouse IL-17A promoted the growth of hepatocellular carcinoma. The tumor-promoting effect of IL-17A was mediated through suppression of antitumor responses, especially CD8+ T-cell responses. Furthermore, we found that IL-17A was produced mainly by Vγ4 γδ T cells, insofar as depleting Vγ4 γδ T cells reduced tumor growth, whereas adoptive transfer of Vγ4 γδ T cells promoted tumor growth. Mechanistic investigations showed that IL-17A induced CXCL5 production by tumor cells to enhance the infiltration of myeloid-derived suppressor cells (MDSC) to tumor sites in a CXCL5/CXCR2–dependent manner. IL-17A also promoted the suppressive activity of MDSC to reinforce suppression of tumoral immunity. Moreover, we found that MDSC could induce IL-17A–producing γδ T cells via production of IL-1β and IL-23. Conversely, IL-17A could also enhance production of IL-1β and IL-23 in MDSC as a positive feedback. Together, our results revealed a novel mechanism involving cross-talk among γδ T cells, MDSCs, and tumor cells through IL-17A production. These findings offer new insights into how IL-17A influences tumor immunity, with potential implications for the development of tumor immunotherapy. Cancer Res; 74(7); 1969–82. ©2014 AACR.
A Common Cancer-Associated DNA Polymerase ϵ Mutation Causes an Exceptionally Strong Mutator Phenotype, Indicating Fidelity Defects Distinct from Loss of Proofreading
Authors: Kane Daniel P. , Shcherbakova Polina V.
Published: February 2014

Exonucleolytic proofreading and DNA mismatch repair (MMR) act in series to maintain high-fidelity DNA replication and to avoid mutagenesis. MMR defects elevate the overall mutation rate and are associated with increased cancer incidence. Hypermutable colorectal and endometrial tumors with functional MMR were recently reported to carry amino acid substitutions in the exonuclease domain of DNA polymerase ϵ (Polϵ). This created a notion that loss of the proofreading activity of Polϵ is an initiating cause of some sporadic human cancers. In this study, we identified a somatic P286R substitution in the conserved ExoI motif of Polϵ in a collection of 52 sporadic colorectal tumor specimens. This change has been repeatedly observed in colorectal and endometrial tumors in previous studies despite many possible ways to inactivate Polϵ proofreading. To understand the reasons for the recurrent appearance of the P286R variant, we characterized its functional consequences using the yeast model system. An analogous substitution in the yeast Polϵ produced an unusually strong mutator phenotype exceeding that of proofreading-deficient mutants by two orders of magnitude. This argues that the P286R mutation acts at some level other than loss of exonuclease to elevate cancer risk. Heterozygosity for the variant allele caused a strong mutator effect comparable with that of complete MMR deficiency, providing an explanation for why loss of heterozygosity is not required for the development of Polϵ-mutant human tumors. Cancer Res; 74(7); 1895–901. ©2014 AACR.
Sedentary Behavior and Prostate Cancer Risk in the NIH–AARP Diet and Health Study
Authors: Lynch Brigid M. , Friedenreich Christine M. , Kopciuk Karen A. , Hollenbeck Albert R. , Moore Steven C. , Matthews Charles E.
Published: February 2014

Sedentary behavior (sitting time) has been proposed as an independent risk factor for some cancers; however, its role in the development of prostate cancer has not been determined. We examined the prospective associations of self-reported daily sitting time and daily television/video viewing time with the risk of developing or dying from prostate cancer among 170,481 men in the NIH–AARP Diet and Health Study. We estimated HRs and 95% confidence intervals (CI) using Cox proportional hazards regression. Between 1996 and 2006, there were 13,751 incident (including 1,365 advanced) prostate cancer cases identified; prostate cancer mortality (through 2008) was 669. No strong or significant association with prostate cancer risk was seen in fully adjusted models for either daily sitting or television/video time. There were some suggestions of effect modification by body mass index (BMI; interaction for television/video time and BMI, P = 0.02). For total prostate cancer risk, television/video time was associated with a slightly elevated, but nonsignificant, increase amongst obese men (HR = 1.28; 95% CI, 0.98–1.69); a null association was observed amongst overweight men (HR = 1.04; 0.89–1.22); and, for men with a normal BMI, television/video time was associated with a nonsignificant risk decrease (HR = 0.82; 95% CI, 0.66–1.01). Similar patterns were observed for total daily sitting and television/video time in advanced prostate cancer and prostate cancer mortality. Sedentary behavior seems to play a limited role in the development of prostate cancer; however, we cannot rule out potential effect modification by BMI or the impact of measurement error on results. Cancer Epidemiol Biomarkers Prev; 23(5); 882–9. ©2014 AACR.
A Distinct Metabolic Signature of Human Colorectal Cancer with Prognostic Potential
Authors: Qiu Yunping , Cai Guoxiang , Zhou Bingsen , Li Dan , Zhao Aihua , Xie Guoxiang , Li Houkai , Cai Sanjun , Xie Dong , Huang Changzhi , Ge Weiting , Zhou Zhanxiang , Xu Lisa X. , Jia Weiping , Zheng Shu , Yen Yun , Jia Wei
Published: February 2014

Purpose: Metabolic phenotyping has provided important biomarker findings, which, unfortunately, are rarely replicated across different sample sets due to the variations from different analytical and clinical protocols used in the studies. To date, very few metabolic hallmarks in a given cancer type have been confirmed and validated by use of a metabolomic approach and other clinical modalities. Here, we report a metabolomics study to identify potential metabolite biomarkers of colorectal cancer with potential theranostic value.

Experimental Design: Gas chromatography–time-of-flight mass spectrometry (GC–TOFMS)–based metabolomics was used to analyze 376 surgical specimens, which were collected from four independent cohorts of patients with colorectal cancer at three hospitals located in China and City of Hope Comprehensive Cancer Center in the United States. Differential metabolites were identified and evaluated as potential prognostic markers. A targeted transcriptomic analysis of 29 colorectal cancer and 27 adjacent nontumor tissues was applied to analyze the gene expression levels for key enzymes associated with these shared metabolites.

Results: A panel of 15 significantly altered metabolites was identified, which demonstrates the ability to predict the rate of recurrence and survival for patients after surgery and chemotherapy. The targeted transcriptomic analysis suggests that the differential expression of these metabolites is due to robust metabolic adaptations in cancer cells to increased oxidative stress as well as demand for energy, and macromolecular substrates for cell growth and proliferation.

Conclusions: These patients with colorectal cancer, despite their varied genetic background, mutations, pathologic stages, and geographic locations, shared a metabolic signature that is of great prognostic and therapeutic potential. Clin Cancer Res; 20(8); 2136–46. ©2014 AACR.
Inhibition of RET Increases the Efficacy of Antiestrogen and Is a Novel Treatment Strategy for Luminal Breast Cancer
Authors: Spanheimer Philip M. , Park Jung-Min , Askeland Ryan W. , Kulak Mikhail V. , Woodfield George W. , De Andrade James P. , Cyr Anthony R. , Sugg Sonia L. , Thomas Alexandra , Weigel Ronald J.
Published: February 2014

Purpose: Recent findings suggest that combination treatment with antiestrogen and anti-RET may offer a novel treatment strategy in a subset of patients with breast cancer. We investigated the role of RET in potentiating the effects of antiestrogen response and examined whether RET expression predicted the ability for tyrosine kinase inhibitor (TKI) to affect extracellular signal–regulated kinase 1/2 (ERK1/2) activation in primary breast cancer.

Experimental Design: Growth response, ERK1/2 activation, Ki-67, and terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling were assessed in breast cancer cell lines in vitro and in xenografts with vandetanib and/or tamoxifen. Thirty tumors with matched normal breast tissue were evaluated for RET expression and response to TKI treatment.

Results: Vandetanib potentiated the inhibitory effect of tamoxifen in hormone responsive (P = 0.01) and hormone insensitive (P < 0.001) estrogen receptor α (ERα)-positive breast cancer cells. Vandetanib significantly repressed tumorigenesis of MCF-7 xenografts (P < 0.001), which displayed decreased activation of ERK1/2 and AKT. Vandetanib and tamoxifen reduced the growth of established tumors with a greater effect of dual therapy compared with single agent (P = 0.003), with tamoxifen-reducing proliferative index and vandetanib-inducing apoptosis. In primary breast cancers, RET expression correlated with the ERα-positive subtype. Relative decrease in ERK1/2 phosphorylation with TKI treatment was 42% (P < 0.001) in RET-positive tumors versus 14% (P = ns) in RET-negative tumors.

Conclusions: Vandetanib potentiated the antigrowth effects of tamoxifen in breast cancer, which was mediated through RET activation. RET predicted response to TKI therapy with minimal effects on ERK1/2 activation in RET-negative tumors. The preclinical data support evaluation of antiestrogen in combination with TKI as a potential treatment strategy for RET-positive luminal breast cancer. Clin Cancer Res; 20(8); 2115–25. ©2014 AACR.
Aberrant Presentation of HPA-Reactive Carbohydrates Implies Selectin-Independent Metastasis Formation in Human Prostate Cancer
Authors: Lange Tobias , Kupfernagel Mareike , Wicklein Daniel , Gebauer Florian , Maar Hanna , Brügge Kathrin , Müller Imke , Simon Ronald , Schlomm Thorsten , Sauter Guido , Schumacher Udo
Published: February 2014

Purpose: To investigate the impact of prostate cancer cell surface glycosylation as part of the tumor cell–endothelial cell interaction in prostate cancer metastasis.

Experimental Design: Glycosyltransferase expression was profiled in metastasis-derived prostate cancer cell lines and compared with primary epithelium. Prostate cancer cells were examined for HPA- and selectin-binding and adhesion to endothelium. Spontaneous metastasis xenograft models were established to test the lectin HPA-binding sites as a marker of metastatic competence and to evaluate E-selectin-binding sites in vivo. The importance of selectins for metastasis formation was analyzed using Sele−/−/Selp−/− mice. The clinical relevance of HPA- and E-selectin-binding sites in prostate cancer was determined.

Results: Glycosyltransferases involved in the synthesis of common HPA-binding sites are downregulated in prostate cancer cells. An absence of HPA-reactive carbohydrates specifically indicates spontaneous metastatic spread of prostate cancer xenografts in vivo and a poor prognosis of patients with prostate cancer. HPA-binding sites decrease in lymph node metastases compared with corresponding primary tumors. Common selectin ligands are absent on prostate cancer cells, which do not adhere to recombinant selectins or endothelium under shear stress in vitro. Spontaneous metastasis formation is largely independent of selectins in vivo. E-selectin-binding sites are detectable in only 2% of patients with prostate cancer without prognostic significance.

Conclusion: Prostate cancer is characterized by an inverse functional and prognostic importance of HPA-binding sites compared with other adenocarcinomas. Accordingly, this study surprisingly shows that the selectin–selectin ligand axis, which is essential for extravasation and thus metastasis formation in several malignancies, can be circumvented in prostate cancer. Clin Cancer Res; 20(7); 1791–802. ©2014 AACR.
Preclinical Evaluation of AMG 925, a FLT3/CDK4 Dual Kinase Inhibitor for Treating Acute Myeloid Leukemia
Authors: Keegan Kathleen , Li Cong , Li Zhihong , Ma Ji , Ragains Mark , Coberly Suzanne , Hollenback David , Eksterowicz John , Liang Lingming , Weidner Margaret , Huard Justin , Wang Xianghong , Alba Grace , Orf Jessica , Lo Mei-Chu , Zhao Sharon , Ngo Rachel , Chen Ada , Liu Lily , Carlson Timothy , Quéva Christophe , McGee Lawrence R. , Medina Julio , Kamb Alexander , Wickramasinghe Dineli , Dai Kang
Published: February 2014

Acute myeloid leukemia (AML) remains a serious unmet medical need. Despite high remission rates with chemotherapy standard-of-care treatment, the disease eventually relapses in a major proportion of patients. Activating Fms-like tyrosine kinase 3 (FLT3) mutations are found in approximately 30% of patients with AML. Targeting FLT3 receptor tyrosine kinase has shown encouraging results in treating FLT3-mutated AML. Responses, however, are not sustained and acquired resistance has been a clinical challenge. Treatment options to overcome resistance are currently the focus of research. We report here the preclinical evaluation of AMG 925, a potent, selective, and bioavailable FLT3/cyclin-dependent kinase 4 (CDK4) dual kinase inhibitor. AMG 925 inhibited AML xenograft tumor growth by 96% to 99% without significant body weight loss. The antitumor activity of AMG 925 correlated with the inhibition of STAT5 and RB phosphorylation, the pharmacodynamic markers for inhibition of FLT3 and CDK4, respectively. In addition, AMG 925 was also found to inhibit FLT3 mutants (e.g., D835Y) that are resistant to the current FLT3 inhibitors (e.g., AC220 and sorafenib). CDK4 is a cyclin D–dependent kinase that plays an essential central role in regulating cell proliferation in response to external growth signals. A critical role of the CDK4–RB pathway in cancer development has been well established. CDK4-specific inhibitors are being developed for treating RB-positive cancer. AMG 925, which combines inhibition of two kinases essential for proliferation and survival of FLT3-mutated AML cells, may improve and prolong clinical responses. Mol Cancer Ther; 13(4); 880–9. ©2014 AACR.
EZH2: Not EZHY (Easy) to Deal
Authors: Deb Gauri , Singh Anup Kumar , Gupta Sanjay
Published: February 2014

Seminal discoveries have established that epigenetic modifications are important for driving tumor progression. Polycomb group (PcG) proteins are highly conserved epigenetic effectors that maintain, by posttranslational modification of histones, the silenced state of genes involved in critical biologic processes, including cellular development, stem cell plasticity, and tumor progression. PcG proteins are found in two multimeric protein complexes called Polycomb repressive complexes: PRC1 and PRC2. Enhancer of zeste homolog 2 (EZH2), catalytic core subunit of PRC2, epigenetically silences several tumor-suppressor genes by catalyzing the trimethylation of histone H3 at lysine 27, which serves as a docking site for DNA methyltransferases and histone deacetylases. Evidence suggests that overexpression of EZH2 is strongly associated with cancer progression and poor outcome in disparate cancers, including hematologic and epithelial malignancies. The regulatory circuit and molecular cues causing EZH2 deregulation vary in different cancer types. Therefore, this review provides a comprehensive overview on the oncogenic role of EZH2 during tumorigenesis and highlights the multifaceted role of EZH2, as either a transcriptional activator or repressor depending on the cellular context. Additional insight is provided on the recent understanding of the causes and consequences of EZH2 overexpression in specific cancer types. Finally, evidence is discussed on how EZH2 has emerged as a promising target in anticancer therapy and the prospects for targeting EZH2 without affecting global methylation status. Thus, a better understanding of the complex epigenetic regulatory network controlling EZH2 expression and target genes facilitates the design of novel therapeutic interventions. Mol Cancer Res; 12(5); 639–53. ©2014 AACR.
Regulation of an Inflammatory Disease
Authors: Jain Mukesh K. , Sangwung Panjamaporn , Hamik Anne
Published: February 2014

This invited review summarizes work presented in the Russell Ross lecture delivered at the 2012 proceedings of the American Heart Association. We begin with a brief overview of the structural, cellular, and molecular biology of Krüppel-like factors. We then focus on discoveries during the past decade, implicating Krüppel-like factors as key determinants of vascular cell function in atherosclerotic vascular disease.
Skin Autofluorescence Is Associated With 5-Year Mortality and Cardiovascular Events in Patients With Peripheral Artery Disease
Authors: de Vos Lisanne C. , Mulder Douwe J. , Smit Andries J. , Dullaart Robin P.F. , Kleefstra Nanne , Lijfering Willem M. , Kamphuisen Pieter W. , Zeebregts Clark J. , Lefrandt Joop D.
Published: February 2014

Objective—

Advanced glycation end products play a pivotal role in atherosclerosis. Recently, we showed that tissue advanced glycation end products deposition, noninvasively assessed by skin autofluorescence (SAF), is increased in patients with peripheral artery disease. The aim of the present study was to establish whether SAF is associated with all-cause mortality and with fatal or nonfatal major adverse cardiovascular events (MACE) in patients with peripheral artery disease.

Approach and Results—

We performed a single-center prospective cohort study of 252 patients with peripheral artery disease (mean age, 66
±
11 years), recruited from the outpatient clinic (October 2007 to June 2008) who were followed until June 2013. SAF was measured with the AGE Reader. The primary end point was all-cause mortality, and the secondary end point was fatal or nonfatal MACE, defined as cardiovascular death and nonfatal myocardial infarction or stroke. During a median follow-up of 5.1 (interquartile range, 5.0–5.3) years, 62 (25%) patients died. Fatal or nonfatal MACE occurred in 62 (25%) patients. A higher SAF was associated with increased risk for all-cause mortality (hazard ratio per unit increase, 2.01; 95% confidence interval, 1.40–2.88;
P
=0.0002) and fatal or nonfatal MACE (hazard ratio, 1.82; 95% confidence interval, 1.28–2.60;
P
=0.001), also after adjustment for cardiovascular risk factors and the use of lipid-lowering drugs (hazard ratio, 1.63; 95% confidence interval, 1.13–2.34;
P
=0.009 and hazard ratio, 1.50; 95% confidence interval, 1.04–2.17;
P
=0.03, for all-cause mortality and fatal and nonfatal MACE, respectively).

Conclusions—

SAF as a measure of advanced glycation end products deposition is independently associated with all-cause mortality and fatal or nonfatal MACE in patients with peripheral artery disease after a 5-year follow-up.
Defective Angiogenesis Delays Thrombus Resolution
Authors: Alias Sherin , Redwan Bassam , Panzenböck Adelheid , Winter Max P. , Schubert Uwe , Voswinckel Robert , Frey Maria K. , Jakowitsch Johannes , Alimohammadi Arman , Hobohm Lukas , Mangold Andreas , Bergmeister Helga , Sibilia Maria , Wagner Erwin F. , Mayer Eckhard , Klepetko Walter , Hölzenbein Thomas J. , Preissner Klaus T. , Lang Irene M.
Published: February 2014

Objective—

Restoration of patency is a natural target of vascular remodeling after venous thrombosis that involves vascular endothelial cells and smooth muscle cells, as well as leukocytes. Acute pulmonary emboli usually resolve <6 months. However, in some instances, thrombi transform into fibrous vascular obstructions, resulting in occlusion of the deep veins, or in chronic thromboembolic pulmonary hypertension (CTEPH). We proposed that dysregulated thrombus angiogenesis may contribute to thrombus persistence.

Approach and Results—

Mice with an endothelial cell–specific conditional deletion of vascular endothelial growth factor receptor 2/kinase insert domain protein receptor were used in a model of stagnant flow venous thrombosis closely resembling human deep vein thrombosis. Biochemical and functional analyses were performed on pulmonary endarterectomy specimens from patients with CTEPH, a human model of nonresolving venous thromboembolism. Endothelial cell–specific deletion of kinase insert domain protein receptor and subsequent ablation of thrombus vascularization delayed thrombus resolution. In accordance with these findings, organized human CTEPH thrombi were largely devoid of vascular structures. Several vessel-specific genes, such as kinase insert domain protein receptor, vascular endothelial cadherin, and podoplanin, were expressed at lower levels in white CTEPH thrombi than in organizing deep vein thrombi and organizing thrombi from aortic aneurysms. In addition, red CTEPH thrombi attenuated the angiogenic response induced by vascular endothelial growth factor.

Conclusions—

In the present work, we propose a mechanism of thrombus nonresolution demonstrating that endothelial cell–specific deletion of kinase insert domain protein receptor abates thrombus vessel formation, misguiding thrombus resolution. Medical conditions associated with the development of CTEPH may be compromising early thrombus angiogenesis.
Low Oxygen Tension Enhances Endothelial Fate of Human Pluripotent Stem Cells
Authors: Kusuma Sravanti , Peijnenburg Elizabeth , Patel Parth , Gerecht Sharon
Published: February 2014

Objective—

A critical regulator of the developing or regenerating vasculature is low oxygen tension. Precise elucidation of the role of low oxygen environments on endothelial commitment from human pluripotent stem cells necessitates controlled in vitro differentiation environments.

Approach and Results—

We used a feeder-free, 2-dimensional differentiation system in which we could monitor accurately dissolved oxygen levels during human pluripotent stem cell differentiation toward early vascular cells (EVCs). We found that oxygen uptake rate of differentiating human pluripotent stem cells is lower in 5% O
2
compared with atmospheric conditions. EVCs differentiated in 5% O
2
had an increased vascular endothelial cadherin expression with clusters of vascular endothelial cadherin+ cells surrounded by platelet-derived growth factor β+ cells. When we assessed the temporal effects of low oxygen differentiation environments, we determined that low oxygen environments during the early stages of EVC differentiation enhance endothelial lineage commitment. EVCs differentiated in 5% O
2
exhibited an increased expression of vascular endothelial cadherin and CD31 along with their localization to the membrane, enhanced lectin binding and acetylated low-density lipoprotein uptake, rapid cord-like structure formation, and increased expression of arterial endothelial cell markers. Inhibition of reactive oxygen species generation during the early stages of differentiation abrogated the endothelial inductive effects of the low oxygen environments.

Conclusions—

Low oxygen tension during early stages of EVC derivation induces endothelial commitment and maturation through the accumulation of reactive oxygen species, highlighting the importance of regulating oxygen tensions during human pluripotent stem cell-vascular differentiation.
Activation of AKT by O-Linked N-Acetylglucosamine Induces Vascular Calcification in Diabetes Mellitus
Authors: Heath Jack M. , Sun Yong , Yuan Kaiyu , Bradley Wayne E. , Litovsky Silvio , Dell’Italia Louis J. , Chatham John C. , Wu Hui , Chen Yabing
Published: February 2014

Rationale:

Vascular calcification is a serious cardiovascular complication that contributes to the increased morbidity and mortality of patients with diabetes mellitus. Hyperglycemia, a hallmark of diabetes mellitus, is associated with increased vascular calcification and increased modification of proteins by O-linked N-acetylglucosamine (O-GlcNAcylation).

Objective:

We sought to determine the role of protein O-GlcNAcylation in regulating vascular calcification and the underlying mechanisms.

Methods and Results:

Low-dose streptozotocin-induced diabetic mice exhibited increased aortic O-GlcNAcylation and vascular calcification, which was also associated with impaired aortic compliance in mice. Elevation of O-GlcNAcylation by administration of Thiamet-G, a potent inhibitor for O-GlcNAcase that removes O-GlcNAcylation, further accelerated vascular calcification and worsened aortic compliance of diabetic mice in vivo. Increased O-GlcNAcylation, either by Thiamet-G or O-GlcNAcase knockdown, promoted calcification of primary mouse vascular smooth muscle cells. Increased O-GlcNAcylation in diabetic arteries or in the O-GlcNAcase knockdown vascular smooth muscle cell upregulated expression of the osteogenic transcription factor Runx2 and enhanced activation of AKT. O-GlcNAcylation of AKT at two new sites, T430 and T479, promoted AKT phosphorylation, which in turn enhanced vascular smooth muscle cell calcification. Site-directed mutation of AKT at T430 and T479 decreased O-GlcNAcylation, inhibited phosphorylation of AKT at S473 and binding of mammalian target of rapamycin complex 2 to AKT, and subsequently blocked Runx2 transactivity and vascular smooth muscle cell calcification.

Conclusions:

O-GlcNAcylation of AKT at 2 new sites enhanced AKT phosphorylation and activation, thus promoting vascular calcification. Our studies have identified a novel causative effect of O-GlcNAcylation in regulating vascular calcification in diabetes mellitus and uncovered a key molecular mechanism underlying O-GlcNAcylation–mediated activation of AKT.
Regulation of Acetylation of Histone Deacetylase 2 by p300/CBP-Associated Factor/Histone Deacetylase 5 in the Development of Cardiac Hypertrophy
Authors: Eom Gwang Hyeon , Nam Yoon Seok , Oh Jae Gyun , Choe Nakwon , Min Hyun-Ki , Yoo Eun-Kyung , Kang Gaeun , Nguyen Vu Hong , Min Jung-Joon , Kim Jong-Keun , Lee In-Kyu , Bassel-Duby Rhonda , Olson Eric N. , Park Woo Jin , Kook Hyun
Published: February 2014

Rationale:

Histone deacetylases (HDACs) are closely involved in cardiac reprogramming. Although the functional roles of class I and class IIa HDACs are well established, the significance of interclass crosstalk in the development of cardiac hypertrophy remains unclear.

Objective:

Recently, we suggested that casein kinase 2α1–dependent phosphorylation of HDAC2 leads to enzymatic activation, which in turn induces cardiac hypertrophy. Here we report an alternative post-translational activation mechanism of HDAC2 that involves acetylation of HDAC2 mediated by p300/CBP-associated factor/HDAC5.

Methods and Results:

Hdac2 was acetylated in response to hypertrophic stresses in both cardiomyocytes and a mouse model. Acetylation was reduced by a histone acetyltransferase inhibitor but was increased by a nonspecific HDAC inhibitor. The enzymatic activity of Hdac2 was positively correlated with its acetylation status. p300/CBP-associated factor bound to Hdac2 and induced acetylation. The HDAC2 K75 residue was responsible for hypertrophic stress–induced acetylation. The acetylation-resistant Hdac2 K75R showed a significant decrease in phosphorylation on S394, which led to the loss of intrinsic activity. Hdac5, one of class IIa HDACs, directly deacetylated Hdac2. Acetylation of Hdac2 was increased in Hdac5-null mice. When an acetylation-mimicking mutant of Hdac2 was infected into cardiomyocytes, the antihypertrophic effect of either nuclear tethering of Hdac5 with leptomycin B or Hdac5 overexpression was reduced.

Conclusions:

Taken together, our results suggest a novel mechanism by which the balance of HDAC2 acetylation is regulated by p300/CBP-associated factor and HDAC5 in the development of cardiac hypertrophy.
Comparison of Medicare Claims Versus Physician Adjudication for Identifying Stroke Outcomes in the Women’s Health Initiative
Authors: Lakshminarayan Kamakshi , Larson Joseph C. , Virnig Beth , Fuller Candace , Allen Norrina Bai , Limacher Marian , Winkelmayer Wolfgang C. , Safford Monika M. , Burwen Dale R.
Published: February 2014

Background and Purpose—

Many studies use medical record review for ascertaining outcomes. One large, longitudinal study, the Women’s Health Initiative (WHI), ascertains strokes using participant self-report and subsequent physician review of medical records. This is resource-intensive. Herein, we assess whether Medicare data can reliably assess stroke events in the WHI.

Methods—

Subjects were WHI participants with fee-for-service Medicare. Four stroke definitions were created for Medicare data using discharge diagnoses in hospitalization claims: definition 1, stroke codes in any position; definition 2, primary position stroke codes; and definitions 3 and 4, hemorrhagic and ischemic stroke codes, respectively. WHI data were randomly split into training (50%) and test sets. A concordance matrix was used to examine the agreement between WHI and Medicare stroke diagnosis. A WHI stroke and a Medicare stroke were considered a match if they occurred within ±7 days of each other. Refined analyses excluded Medicare events when medical records were unavailable for comparison.

Results—

Training data consisted of 24 428 randomly selected participants. There were 577 WHI strokes and 557 Medicare strokes using definition 1. Of these, 478 were a match. With regard to algorithm performance, specificity was 99.7%, negative predictive value was 99.7%, sensitivity was 82.8%, positive predictive value was 85.8%, and κ=0.84. Performance was similar for test data. Whereas specificity and negative predictive value exceeded 99%, sensitivity ranged from 75% to 88% and positive predictive value ranged from 80% to 90% across stroke definitions.

Conclusions—

Medicare data seem useful for population-based stroke research; however, performance characteristics depend on the definition selected.
Who Benefits from Pension Enhancements?
Authors: Koedel Cory , Ni Shawn , Podgursky Michael
Published: February 2014

During the late 1990s public pension funds across the United States accrued large actuarial surpluses. The seemingly flush conditions of the pension funds led legislators in most states to substantially improve retirement benefits for public workers, including teachers. In this study we examine the benefit enhancements to the teacher pension system in Missouri. The enhancements resulted in large windfall gains for teachers who were close to retirement when the legislation was enacted. By contrast, novice teachers, and teachers who had not yet entered the labor force, were made worse off. The reason is that front-end contribution rates have been raised for current teachers to offset past liabilities accrued from the enhancements. Total teacher retirement compensation, net of contribution costs, is lower for young teachers today as a result of the enhancement legislation. Given sharp increases in pension costs in other states, this finding may generalize to young teachers in many other plans.
Virtual Rehabilitation Environment Using Principles of Intrinsic Motivation and Game Design
Authors: Mihelj Matjaž , Novak Domen , Milavec Maja , Ziherl Jaka , Olenšek Andrej , Munih Marko
Published: February 2014

This paper presents a novel multimodal virtual rehabilitation environment. Its design and implementation are based on principles related to intrinsic motivation and game design. The system consists of visual, acoustic, and haptic modalities. Elements contributing to intrinsic motivation are carefully joined in the three modalities to increase patients' motivation during the long process of rehabilitation. The message in a bottle (MIB) virtual scenario is designed to allow interplay between motor and cognitive challenges in the exercising patient. The user first needs to perform a motor action to receive a cognitive challenge that is finally solved by a second motor action. Visual feedback provides the most relevant information related to the task. Acoustic feedback consists of environmental sounds, music, and spoken instructions or encouraging statements for the patient. The haptic modality generates tactile information related to the environment and provides various modes of assistance for the patient's arm movements. The MIB scenario was evaluated with 16 stroke patients, who rated it positively using the Intrinsic Motivation Inventory questionnaire. Additionally, the MIB scenario seems to elicit higher motivation than a simpler pick-and-place training task.
A Dual-Modal Virtual Reality Kitchen for (Re)Learning of Everyday Cooking Activities in Alzheimer's Disease
Authors: Yamaguchi Takehiko , Foloppe Déborah Alexandra , Richard Paul , Richard Emmanuelle , Allain Philippe
Published: February 2014

Everyday action impairment is one of the diagnostic criteria of Alzheimer's disease and is associated with many serious consequences, including loss of functional autonomy and independence. It has been shown that the (re)learning of everyday activities is possible in Alzheimer's disease by using error reduction teaching approaches in naturalistic clinical settings. The purpose of this study is to develop a dual-modal virtual reality platform for training in everyday cooking activities in Alzheimer's disease and to establish its value as a training tool for everyday activities in these patients. Two everyday tasks and two error reduction learning methods were implemented within a virtual kitchen. Two patients with Alzheimer's disease and two healthy elderly controls were tested. All subjects were trained in two learning sessions on two comparable cooking tasks. Within each group (i.e., patients and controls), the order of the training methods was counterbalanced. Repeated measure analysis before and after learning was performed. A questionnaire of presence and a verbal interview were used to obtain information about the subjective responses of the participants to the VR experience. The results in terms of errors, omissions, and perseverations (i.e., repetitive behaviors) indicate that the patients performed worse than the controls before learning, but that they reached a level of performance similar to that of the controls after a short learning session, regardless of the learning method employed. This finding provides preliminary support for the value of the dual-modal virtual reality platform for training in everyday cooking activities in Alzheimer's disease. However, further work is needed before it is ready for clinical application.
Gameplay as a Source of Intrinsic Motivation for Individuals in Need of Ankle Training or Rehabilitation
Authors: Nilsson Niels Christian , Serafin Stefania , Nordahl Rolf
Published: February 2014

Injuries to the ankle may be a source of great discomfort and the long-term effects can negatively influence the future health of the individual who has suffered the injury. Wobble boards represent a relatively inexpensive type of equipment that may be used to train one's ankles preventively or as part of the rehabilitation process once the damage has been done. However, individuals in need of such training frequently lack the motivation necessary in order to successfully complete the training or rehabilitation process. This paper details the design and implementation of a prototype intended to alleviate this problem by leveraging games' potential as a source of intrinsic motivation. More specifically, the prototype enables users to control a game by means of a wobble board, thus allowing them to perform the necessary exercises while playing. An expert on ankle rehabilitation assessed the efficacy of the training facilitated by the prototype, and 40 individuals partook in a quantitative test performed in order to determine whether the prototype could potentially provide the needed motivation. Based on the findings from the two tests, it is concluded that the prototype does ensure correct ankle training and the act of playing was experienced as intrinsically motivating by the majority of the test participants.
Acting Rehearsal in Collaborative Multimodal Mixed Reality Environments
Authors: Steptoe William , Normand Jean-Marie , Oyekoya Oyewole , Pece Fabrizio , Giannopoulos Elias , Tecchia Franco , Steed Anthony , Weyrich Tim , Kautz Jan , Slater Mel
Published: February 2014

This paper presents the use of our multimodal mixed reality telecommunication system to support remote acting rehearsal. The rehearsals involved two actors, located in London and Barcelona, and a director in another location in London. This triadic audiovisual telecommunication was performed in a spatial and multimodal collaborative mixed reality environment based on the “destination-visitor” paradigm, which we define and put into use. We detail our heterogeneous system architecture, which spans the three distributed and technologically asymmetric sites, and features a range of capture, display, and transmission technologies. The actors' and director's experience of rehearsing a scene via the system are then discussed, exploring successes and failures of this heterogeneous form of telecollaboration. Overall, the common spatial frame of reference presented by the system to all parties was highly conducive to theatrical acting and directing, allowing blocking, gross gesture, and unambiguous instruction to be issued. The relative inexpressivity of the actors' embodiments was identified as the central limitation of the telecommunication, meaning that moments relying on performing and reacting to consequential facial expression and subtle gesture were less successful.
Modeling Dynamic Interaction in Virtual Environments and the Evaluation of Dynamic Virtual Fixtures
Authors: Richard Paul , Naud Mickael , Inglese Francois-Xavier , Richard Emmanuelle
Published: February 2014

Virtual reality (VR) is a technology covering a large field of applications among which are sports and video games. In both gaming and sporting VR applications, interaction techniques involve specific gestures such as catching or striking. However, such dynamic gestures are not currently being recognized as elementary task primitives, and have therefore not been investigated as such. In this paper, we propose a framework for the analysis of interaction in dynamic virtual environments (DVEs). This framework is based on three dynamic interaction primitives (DIPs) that are common to many sporting activities: catching, throwing, and striking. For each of these primitives, an original modeling approach is proposed. Furthermore, we introduce and formalize the concept of dynamic virtual fixtures (DVFs). These fixtures aim to assist the user in tasks involving interaction with moving objects or with objects to be set in movement. Two experiments have been carried out to investigate the influence of different DVFs on human performance in the context of ball catching and archery. The results reveal a significant positive effect of the DVFs, and that DVFs could be either classified as “performance-assisted” or “learning-assisted.”
Problem-based Learning for Design and Engineering Activities in Virtual Worlds
Authors: Vosinakis Spyros , Koutsabasis Panayiotis
Published: February 2014

There are a growing number of problem-based learning (PBL) studies in virtual worlds (VWs); however, the suitability of these approaches is still unknown for particular knowledge domains and in full-time courses. In this paper, we argue that VWs can support a constructionist approach to PBL for blended-practice-based courses of design and engineering, and we describe an instructional design framework and its application at an HCI (human–computer interaction) design course. The approach places emphasis on learning by doing, and enables students to collaboratively work in authentic and ill-defined situations, follow self-directed routes to address problems, and construct digital artifacts as candidate solutions. The proposed approach translates the principles of PBL into guidelines for setting up a VW as a learning environment, building supporting tools, and implementing learning activities that require that students create digital models that reflect their understanding about their learning. We have applied the framework in a blended postgraduate course in HCI design that involved various PBL activities and the application of methods related to the lifecycle of interactive product development (including user research, conceptual design, prototyping, and usability evaluation). The results were encouraging with respect to the applicability of the approach, students' acceptance, as well as perceived usability of the VW environment and tools in the long term.
Case Study: Using a Novel Virtual Reality Computer Game for Occupational Therapy Intervention
Authors: Tresser Sarit
Published: February 2014

The past decade has seen the emergence of rehabilitation treatments using virtual reality environments. One of the main advantages of using this technology is that it creates positive motivation. Currently, most virtual-reality-based games for children are not suitable for use in a therapeutic setting. This case study reports on the use of Growing with Timocco, a specially devised virtual reality computer game, as part of an occupational therapy regimen that addressed the developmental needs of a five-year-old patient diagnosed with dyspraxia, impaired postural structure, weak shoulder, and insufficient bilateral integration, bilateral coordination, and proprioception regulation. Developed specifically for use by occupational therapists and caregivers working with children, Growing with Timocco is equipped to provide exercises for both cognitive and motor skills, but most importantly, it provides a positive setting for this practice, by harnessing the advantages of VR to promote play, pleasure, and motivation.
Multimodal Data Capture and Analysis of Interaction in Immersive Collaborative Virtual Environments
Authors: Steptoe William , Steed Anthony
Published: February 2014

Users of immersive virtual reality (VR) are often observed to act realistically on social, behavioral, physiological, and subjective levels. However, experimental studies in the field typically collect and analyze metrics independently, which fails to consider the synchronous and multimodal nature of the original human activity. This paper concerns multimodal data capture and analysis in immersive collaborative virtual environments (ICVEs) in order to enable a holistic and rich analysis based on techniques from interaction analysis. A reference architecture for collecting multimodal data specifically for immersive VR is presented. It collates multiple components of a user's nonverbal and verbal behavior in single log file, thereby preserving the temporal relationships between cues. Two case studies describing sequences of immersive avatar-mediated communication (AMC) demonstrate the ability of multimodal data to preserve a rich description of the original mediated social interaction. Analyses of the sequences using techniques from interaction analysis emphasize the causal interrelationships between the captured components of human behavior, leading to a deeper understanding of how and why the communication may have unfolded. In presenting our logging architecture, we hope that we will initiate a discussion of a logging standard that can be built by the community so that practitioners can share data and build better tools to analyze the utility of VR.
The Sense of Embodiment in Virtual Reality
Authors: Kilteni Konstantina , Groten Raphaela , Slater Mel
Published: February 2014

What does it feel like to own, to control, and to be inside a body? The multidimensional nature of this experience together with the continuous presence of one's biological body, render both theoretical and experimental approaches problematic. Nevertheless, exploitation of immersive virtual reality has allowed a reframing of this question to whether it is possible to experience the same sensations towards a virtual body inside an immersive virtual environment as toward the biological body, and if so, to what extent. The current paper addresses these issues by referring to the Sense of Embodiment (SoE). Due to the conceptual confusion around this sense, we provide a working definition which states that SoE consists of three subcomponents: the sense of self-location, the sense of agency, and the sense of body ownership. Under this proposed structure, measures and experimental manipulations reported in the literature are reviewed and related challenges are outlined. Finally, future experimental studies are proposed to overcome those challenges, toward deepening the concept of SoE and enhancing it in virtual applications.