bluuebunny/crossref_metadata_2025 huggingface dataset:
Low Surface Expression of B7-1 (CD80) Is an Immunoescape Mechanism of Colon Carcinoma
Authors: Tirapu Iñigo , Huarte Eduardo , Guiducci Cristiana , Arina Ainhoa , Zaratiegui Mikel , Murillo Oihana , Gonzalez Alvaro , Berasain Carmen , Berraondo Pedro , Fortes Puri , Prieto Jesús , Colombo Mario P. , Chen Lieping , Melero Ignacio
Published: February 2006

Artificially enforced expression of CD80 (B7-1) and CD86 (B7-2) on tumor cells renders them more immunogenic by triggering the CD28 receptor on T cells. The enigma is that such B7s interact with much higher affinity with CTLA-4 (CD152), an inhibitory receptor expressed by activated T cells. We show that unmutated CD80 is spontaneously expressed at low levels by mouse colon carcinoma cell lines and other transplantable tumor cell lines of various tissue origins. Silencing of CD80 by interfering RNA led to loss of tumorigenicity of CT26 colon carcinoma in immunocompetent mice, but not in immunodeficient Rag−/− mice. CT26 tumor cells bind CTLA-4Ig, but much more faintly with a similar CD28Ig chimeric protein, thus providing an explanation for the dominant inhibitory effects on tumor immunity displayed by CD80 at that expression level. Interestingly, CD80-negative tumor cell lines such as MC38 colon carcinoma and B16 melanoma express CD80 at dim levels during in vivo growth in syngeneic mice. Therefore, low CD80 surface expression seems to give an advantage to cancer cells against the immune system. Our findings are similar with the inhibitory role described for the dim CD80 expression on immature dendritic cells, providing an explanation for the low levels of CD80 expression described in various human malignancies. (Cancer Res 2006; 66(4): 2442-50)
Activating Transcription Factor 3 and Early Growth Response 1 Are the Novel Targets of LY294002 in a Phosphatidylinositol 3-Kinase–Independent Pathway
Authors: Yamaguchi Kiyoshi , Lee Seong-Ho , Kim Jong-Sik , Wimalasena Jay , Kitajima Shigetaka , Baek Seung Joon
Published: February 2006

LY294002, a phosphatidylinositol 3-kinase (PI3K) inhibitor, has been widely used to study the function of PI3K in cellular responses. Based on its inhibitory effect on PI3K, LY294002 has been shown to exert antitumorigenic effect in vivo and in vitro. Here, we report that LY294002 alters early growth response 1 (EGR-1) phosphorylation and subsequently enhances activating transcription factor 3 (ATF3) expression independently of PI3K inhibition. This pathway may be, in part, responsible for the antitumorigenic effect of LY294002 in human colorectal cancer cells. ATF3 expression was increased by LY294002, followed by the induction of apoptosis in several colorectal cancer cell lines. This is consistent with results showing that the down-regulation of the ATF3 gene by small interfering RNA suppressed LY294002-induced apoptosis in HCT-116 cells. On the other hand, ATF3 expression was not affected by another PI3K inhibitor, wortmannin, as well as phosphatase and tensin homologue or dominant-negative Akt overexpression. We also found that LY294002 increases ATF3 promoter activity and the transactivation is partly mediated by a GC-rich sequence located in the promoter. EGR-1 binds to the ATF3 promoter as assessed by gel shift assay. Furthermore, phosphorylated EGR-1 was highly increased in LY294002-treated cells, indicating that EGR-1 phosphorylation induced by LY294002 may facilitate ATF3 transactivation. Our data suggest that EGR-1 acts as a mediator in LY294002-induced ATF3 expression via a PI3K-independent pathway. ATF3 and EGR-1 may provide a novel explanation for the antitumorigenic properties of LY294002 in human colorectal cancer cells. (Cancer Res 2006; 66(4): 2376-84)
Induction of Centrosome Amplification during Arsenite-Induced Mitotic Arrest in CGL-2 Cells
Authors: Yih Ling-Huei , Tseng Yun-Yu , Wu Yi-Chen , Lee Te-Chang
Published: February 2006

Arsenite-induced mitotic abnormalities result in mitotic death in several cancer cell lines. However, how arsenite induces these effects is not known. We have previously shown that arsenite induces mitotic arrest, mitotic abnormalities, and mitotic death in CGL-2 cells. To further delineate the mechanism of action of arsenite, we examined its effect on centrosome duplication and the possible link between centrosome dysregulation and arsenite-induced mitotic death. Immunofluorescence staining of γ-tubulin revealed that centrosome amplification was induced in arsenite-arrested mitotic cells but not in nocodazole-arrested cells. When S phase–enriched cells were treated with arsenite, they progressed into and arrested at mitosis and then formed supernumerary centrosomes. A further increase in arsenite-induced centrosome amplification was seen during the prolonged mitotic arrest. The arsenite-induced supernumerary centrosomes might result from uneven fragmentation of centrosome, overexpression of pericentriolar materials, and inhibition of centrosomal coalescence during mitosis. Furthermore, termination of mitotic arrest by treatment of arsenite-arrested mitotic cells with cyclin-dependent kinase 1 inhibitors or by suppression of spindle checkpoint function by small interfering RNA–mediated silencing of BubR1 or Mad2 markedly reduced the induction of centrosome amplification and mitotic death in arsenite-treated cells. These results indicate that centrosome amplification is induced in arsenite-arrested mitotic CGL-2 cells in a spindle checkpoint-dependent manner and is involved in the induction of arsenite-induced mitotic death. (Cancer Res 2006; 66(4): 2098-106)
Mechanism by Which Mammalian Target of Rapamycin Inhibitors Sensitize Multiple Myeloma Cells to Dexamethasone-Induced Apoptosis
Authors: Yan Huajun , Frost Patrick , Shi Yijiang , Hoang Bao , Sharma Sanjai , Fisher Myrna , Gera Joseph , Lichtenstein Alan
Published: February 2006

Mammalian target of rapamycin (mTOR) inhibitors curtail cap-dependent translation. However, they can also induce post-translational modifications of proteins. We assessed both effects to understand the mechanism by which mTOR inhibitors like rapamycin sensitize multiple myeloma cells to dexamethasone-induced apoptosis. Sensitization was achieved in multiple myeloma cells irrespective of their PTEN or p53 status, enhanced by activation of AKT, and associated with stimulation of both intrinsic and extrinsic pathways of apoptosis. The sensitizing effect was not due to post-translational modifications of the RAFTK kinase, Jun kinase, p38 mitogen-activated protein kinase, or BAD. Sensitization was also not associated with a rapamycin-mediated increase in glucocorticoid receptor reporter expression. However, when cap-dependent translation was prevented by transfection with a mutant 4E-BP1 construct, which is resistant to mTOR-induced phosphorylation, cells responded to dexamethasone with enhanced apoptosis, mirroring the effect of coexposure to rapamycin. Thus, sensitization is mediated by inhibition of cap-dependent translation. A high-throughput screening for translational efficiency identified several antiapoptotic proteins whose translation was inhibited by rapamycin. Immunoblot assay confirmed rapamycin-induced down-regulated expressions of XIAP, CIAP1, HSP-27, and BAG-3, which may play a role in the sensitization to apoptosis. Studies in a xenograft model showed synergistic in vivo antimyeloma effects when dexamethasone was combined with the mTOR inhibitor CCI-779. Synergistic effects were associated with an enhanced multiple myeloma cell apoptosis in vivo. This study supports the strategy of combining dexamethasone with mTOR inhibitors in multiple myeloma and identifies a mechanism by which the synergistic effect is achieved. (Cancer Res 2006; 66(4): 2305-13)
Cell Type and Culture Condition–Dependent Alternative Splicing in Human Breast Cancer Cells Revealed by Splicing-Sensitive Microarrays
Authors: Li Chunxia , Kato Mitsuo , Shiue Lily , Shively John E. , Ares Manuel , Lin Ren-Jang
Published: February 2006

Growing evidence indicates that alternative or aberrant pre-mRNA splicing takes place during the development, progression, and metastasis of breast cancer. However, which splicing changes that might contribute directly to tumorigenesis or cancer progression remain to be elucidated. We used splicing-sensitive microarrays to detect differences in alternative splicing between two breast cancer cell lines, MCF7 (estrogen receptor positive) and MDA-MB-231 (estrogen receptor negative), as well as cultured human mammary epithelial cells. Several splicing alterations in genes, including CD44, FAS, RBM9, hnRNPA/B, APLP2, and MYL6, were detected by the microarray and verified by reverse transcription-PCR. We also compared splicing in these breast cancer cells cultured in either two-dimensional flat dishes or in three-dimensional Matrigel conditions. Only a subset of the splicing differences that distinguish MCF7 cells from MDA-MB-231 cells under two-dimensional culture condition is retained under three-dimensional conditions, suggesting that alternative splicing events are influenced by the geometry of the culture conditions of these cells. Further characterization of splicing patterns of several genes in MCF7 cells grown in Matrigel and in xenograft in nude mice shows that splicing is similar under both conditions. Thus, our oligonucleotide microarray can effectively detect changes in alternative splicing in different cells or in the same cells grown in different environments. Our findings also illustrate the potential for understanding gene expression with resolution of alternative splicing in the study of breast cancer. (Cancer Res 2006; 66(4): 1990-9)
Structurally Dependent Redox Property of Ribonucleotide Reductase Subunit p53R2
Authors: Xue Lijun , Zhou Bingsen , Liu Xiyong , Wang Tieli , Shih Jennifer , Qi Christina , Heung Yvonne , Yen Yun
Published: February 2006

p53R2 is a newly identified small subunit of ribonucleotide reductase (RR) and plays a key role in supplying precursors for DNA repair in a p53-dependent manner. Currently, we are studying the redox property, structure, and function of p53R2. In cell-free systems, p53R2 did not oxidize a reactive oxygen species (ROS) indicator carboxy-H2DCFDA, but another class I RR small subunit, hRRM2, did. Further studies showed that purified recombinant p53R2 protein has catalase activity, which breaks down H2O2. Overexpression of p53R2 reduced intracellular ROS and protected the mitochondrial membrane potential against oxidative stress, whereas overexpression of hRRM2 did not and resulted in a collapse of mitochondrial membrane potential. In a site-directed mutagenesis study, antioxidant activity was abrogated in p53R2 mutants Y331F, Y285F, Y49F, and Y241H, but not Y164F or Y164C. The fluorescence intensity in mutants oxidizing carboxy-H2DCFDA, in order from highest to lowest, was Y331F > Y285F > Y49F > Y241H > wild-type p53R2. This indicates that Y331, Y285, Y49, and Y241 in p53R2 are critical residues involved in scavenging ROS. Of interest, the ability to oxidize carboxy-H2DCFDA indicated by fluorescence intensity was negatively correlated with RR activity from wild-type p53R2, mutants Y331F, Y285F, and Y49F. Our findings suggest that p53R2 may play a key role in defending oxidative stress by scavenging ROS, and this antioxidant property is also important for its fundamental enzymatic activity. (Cancer Res 2006; 66(4): 1900-5)
C-fosAssessment as a Marker of Anti–Epidermal Growth Factor Receptor Effect
Authors: Jimeno Antonio , Kulesza Peter , Kincaid Erik , Bouaroud Nadia , Chan Audrey , Forastiere Arlene , Brahmer Julie , Clark Douglas P. , Hidalgo Manuel
Published: February 2006

Factors predicting sensitivity to epidermal growth factor receptor (EGFR) blockade are largely unknown and new strategies are being sought to individualize cancer therapy. This study evaluated the variation in the expression of the early response gene c-fos as a distal effect of EGFR inhibition and its relationship to antitumor effects. The growth-inhibitory and c-fos–modulating effects of gefitinib and erlotinib in human cancer cell lines (A431, CAL27, HN11, HuCCT1, and Hep2) were determined. Next, these cell lines were xenografted in mice and treated for 14 days with gefitinib (A431 and HuCCT1) or erlotinib (CAL27, HN11, and Hep2). Fine needle aspiration biopsy of tumors was done at baseline and after 14 days of therapy for c-fos assessment. In addition, we tested the feasibility of analyzing this marker in five paired tumor samples from a clinical trial of gefitinib in patients with solid tumors. In culture, gefitinib and erlotinib decreased c-fos mRNA levels in the susceptible cell lines A431, CAL27, and HN11; however, both drugs failed to achieve c-fos inhibition in resistant cells. Gefitinib or erlotinib abrogated the increase in c-fos expression in vivo in EGFR-sensitive A431, CAL27, and HN11 tumors but not in resistant strains. Ex vivo evaluation was feasible and predicted in vivo effects. The feasibility study in paired human tumor biopsies showed that this biomarker can be reliably measured in clinical materials. In summary, variations in c-fos expression reflect the pharmacologic actions of EGFR inhibitors in in vitro and in vivo models. (Cancer Res 2006; 66(4): 2385-90)
Genetic and Epigenetic Analysis of von Hippel-Lindau (VHL) Gene Alterations and Relationship with Clinical Variables in Sporadic Renal Cancer
Authors: Banks Rosamonde E. , Tirukonda Prasanna , Taylor Claire , Hornigold Nick , Astuti Dewi , Cohen Dena , Maher Eamonn R. , Stanley Anthea J. , Harnden Patricia , Joyce Adrian , Knowles Margaret , Selby Peter J.
Published: February 2006

Genetic and epigenetic changes in the von Hippel-Lindau (VHL) tumor suppressor gene are common in sporadic conventional renal cell carcinoma (cRCC). Further insight into the clinical significance of these changes may lead to increased biological understanding and identification of subgroups of patients differing prognostically or who may benefit from specific targeted treatments. We have comprehensively examined the VHL status in tissue samples from 115 patients undergoing nephrectomy, including 96 with sporadic cRCC. In patients with cRCC, loss of heterozygosity was found in 78.4%, mutation in 71%, and promoter methylation in 20.4% of samples. Multiplex ligation–dependent probe amplification identified intragenic copy number changes in several samples including two which were otherwise thought to be VHL-noninvolved. Overall, evidence of biallelic inactivation was found in 74.2% of patients with cRCC. Many of the mutations were novel and approximately two-thirds were potentially truncating. Examination of these and other published findings confirmed mutation hotspots affecting codons 117 and 164, and revealed a common region of mutation in codons 60 to 78. Gender-specific differences in methylation and mutation were seen, although not quite achieving statistical significance (P = 0.068 and 0.11), and a possible association between methylation and polymorphism was identified. No significant differences were seen between VHL subgroups with regard to clinicopathologic features including stage, grade, tumor size, cancer-free and overall survival, with the exception of a significant association between loss of heterozygosity and grade, although a possible trend for survival differences based on mutation location was apparent. (Cancer Res 2006; 66(4): 2000-11)
Cell Adhesion to Fibronectin (CAM-DR) Influences Acquired Mitoxantrone Resistance in U937 Cells
Authors: Hazlehurst Lori A. , Argilagos Raul F. , Emmons Michael , Boulware David , Beam Craig A. , Sullivan Dan M. , Dalton William S.
Published: February 2006

Cell adhesion to fibronectin is known to confer a temporally related cell adhesion–mediated drug resistance (CAM-DR). However, it is unknown whether cell adhesion during drug selection influences the more permanent form of acquired drug resistance. To examine this question, we compared the acquisition of mitoxantrone resistance in U937 cells adhered to fibronectin versus cells selected in a traditional suspension culture. Our data show that acquired drug resistance levels of resistance to mitoxantrone are 2- to 3-fold greater for cells adhered to fibronectin compared with cells in suspension culture. We also compared mechanism(s) of resistance associated with drug selection in suspension versus fibronectin-adherent cultures. Drug resistance in both suspension and fibronectin-adhered cultures correlated with reduced drug-induced DNA damage and diminished topoisomerase II levels and activity; however, mechanisms regulating topoisomerase II levels differed depending on culture conditions. In suspension cultures, a reduction in topoisomerase IIβ levels was detected at both RNA and protein levels. Furthermore, the decreased expression of topoisomerase IIβ mRNA levels correlated with decreased expression of NF-YA. In contrast, in spite of no changes in NF-YA or topoisomerase IIβ RNA expression, topoisomerase IIβ protein levels were decreased in fibronectin-adherent, drug-resistant cells. In addition, topoisomerase IIα protein levels (but not RNA levels) were reduced in drug resistance cells selected on fibronectin; however, no change in topoisomerase IIα was observed in cells selected with mitoxantrone in suspension culture. Taken together, our results suggest that the development of drug resistance models must consider interactions with the microenvironment to identify clinically relevant targets and mechanisms associated with acquired drug resistance. (Cancer Res 2006; 66(4): 2338-45)
Reduction of Cytosolic p27Kip1 Inhibits Cancer Cell Motility, Survival, and Tumorigenicity
Authors: Wu Frederick Y. , Wang Shizhen Emily , Sanders Melinda E. , Shin Incheol , Rojo Federico , Baselga Jose , Arteaga Carlos L.
Published: February 2006

We generated a p27Kip1 mutant (p27ΔNLS) that localized exclusively in cell cytosol. Expression of p27ΔNLS in MCF7 breast cancer cells down-regulated RhoA and increased motility, survival, and Akt levels without an effect on cell cycle distribution. RNA interference of p27 in U87 glioma cells, which express p27 predominantly in the cytoplasm, inhibited motility and survival. Conversely, knockdown of p27 in COS7 cells, with >95% nuclear p27 expression, accelerated proliferation but had no effect on motility or survival. U87 cells in which p27 had been eliminated by RNA interference exhibited lower Akt levels, shorter Akt turnover, and markedly impaired tumorigenicity in vivo. These xenografts were less invasive and exhibited increased apoptosis compared with p27-expressing tumors. Expression of cytosolic p27 in primary human breast carcinomas correlated linearly with Akt content as measured by immunohistochemistry. These data suggest that cytoplasmic p27 can exert oncogenic functions by modulating Akt stability, cell survival, and tumorigenicity. (Cancer Res 2006; 66(4): 2162-72)
Genetic and Histopathologic Evaluation ofBRCA1andBRCA2DNA Sequence Variants of Unknown Clinical Significance
Authors: Chenevix-Trench Georgia , Healey Sue , Lakhani Sunil , Waring Paul , Cummings Margaret , Brinkworth Ross , Deffenbaugh Amie M. , Burbidge Lynn Anne , Pruss Dmitry , Judkins Thad , Scholl Tom , Bekessy Anna , Marsh Anna , Lovelock Paul , Wong Ming , Tesoriero Andrea , Renard Helene , Southey Melissa , Hopper John L. , Yannoukakos Koulis , Brown Melissa ,   kConFab Investigators, Easton Douglas , Tavtigian Sean V. , Goldgar David , Spurdle Amanda B.
Published: February 2006

Classification of rare missense variants as neutral or disease causing is a challenge and has important implications for genetic counseling. A multifactorial likelihood model for classification of unclassified variants in BRCA1 and BRCA2 has previously been developed, which uses data on co-occurrence of the unclassified variant with pathogenic mutations in the same gene, cosegregation of the unclassified variant with affected status, and Grantham analysis of the fit between the missense substitution and the evolutionary range of variation observed at its position in the protein. We have further developed this model to take into account relevant features of BRCA1- and BRCA2-associated tumors, such as the characteristic histopathology and immunochemical profiles associated with pathogenic mutations in BRCA1, and the fact that ∼80% of tumors from BRCA1 and BRCA2 carriers undergo inactivation of the wild-type allele by loss of heterozygosity. We examined 10 BRCA1 and 15 BRCA2 unclassified variants identified in Australian, multiple-case breast cancer families. By a combination of genetic, in silico, and histopathologic analyses, we were able to classify one BRCA1 variant as pathogenic and six BRCA1 and seven BRCA2 variants as neutral. Five of these neutral variants were also found in at least 1 of 180 healthy controls, suggesting that screening a large number of appropriate controls might be a useful adjunct to other methods for evaluation of unclassified variants. (Cancer Res 2006; 66(4): 2019-27)
Haplotype Analysis of theHSD17B1Gene and Risk of Breast Cancer: A Comprehensive Approach to Multicenter Analyses of Prospective Cohort Studies
Authors: Feigelson Heather Spencer , Cox David G. , Cann Howard M. , Wacholder Sholom , Kaaks Rudolf , Henderson Brian E. , Albanes Demetrius , Altshuler David , Berglund Goran , Berrino Franco , Bingham Sheila , Buring Julie E. , Burtt Noel P. , Calle Eugenia E. , Chanock Stephen J. , Clavel-Chapelon Francoise , Colditz Graham , Diver W. Ryan , Freedman Matthew L. , Haiman Christopher A. , Hankinson Susan E. , Hayes Richard B. , Hirschhorn Joel N. , Hunter David , Kolonel Laurence N. , Kraft Peter , LeMarchand Loic , Linseisen Jakob , Modi William , Navarro Carmen , Peeters Petra H. , Pike Malcolm C. , Riboli Elio , Setiawan V. Wendy , Stram Daniel O. , Thomas Gilles , Thun Michael J. , Tjonneland Anne , Trichopoulos Dimitrios
Published: February 2006

The 17β-hydroxysteroid dehydrogenase 1 gene (HSD17B1) encodes 17HSD1, which catalyzes the final step of estradiol biosynthesis. Despite the important role of HSD17B1 in hormone metabolism, few epidemiologic studies of HSD17B1 and breast cancer have been conducted. This study includes 5,370 breast cancer cases and 7,480 matched controls from five large cohorts in the Breast and Prostate Cancer Cohort Consortium. We characterized variation in HSD17B1 by resequencing and dense genotyping a multiethnic sample and identified haplotype-tagging single nucleotide polymorphisms (htSNP) that capture common variation within a 33.3-kb region around HSD17B1. Four htSNPs, including the previously studied SNP rs605059 (S312G), were genotyped to tag five common haplotypes in all cases and controls. Conditional logistic regression was used to estimate odds ratios (OR) for disease. We found no evidence of association between common HSD17B1 haplotypes or htSNPs and overall risk of breast cancer. The OR for each haplotype relative to the most common haplotype ranged from 0.98 to 1.07 (omnibus test for association: X2 = 3.77, P = 0.58, 5 degrees of freedom). When cases were subdivided by estrogen receptor (ER) status, two common haplotypes were associated with ER-negative tumors (test for trend, Ps = 0.0009 and 0.0076; n = 353 cases). HSD17B1 variants that are common in Caucasians are not associated with overall risk of breast cancer; however, there was an association among the subset of ER-negative tumors. Although the probability that these ER-negative findings are false-positive results is high, these findings were consistent across each cohort examined and warrant further study. (Cancer Res 2006; 66(4): 2468-75)
A Prospective Study of Serum C-Reactive Protein and Colorectal Cancer Risk in Men
Authors: Gunter Marc J. , Stolzenberg-Solomon Rachael , Cross Amanda J. , Leitzmann Michael F. , Weinstein Stephanie , Wood Richard J. , Virtamo Jarmo , Taylor Philip R. , Albanes Demetrius , Sinha Rashmi
Published: February 2006

Chronic inflammation has been implicated in the etiology of colorectal cancer. C-reactive protein (CRP), a sensitive marker of inflammation, has been investigated with regard to colorectal cancer in only three previous studies, and the results from these investigations were inconsistent. We examined serum CRP levels in relation to colorectal cancer incidence in a nested case-control study within the Alpha Tocopherol, Beta-Carotene (ATBC) Cancer Prevention Study, a cohort of 29,133 Finnish males enrolled from 1985 to 1988 with follow-up through April 2002. Colorectal cancer cases were ascertained by the Finnish Cancer Registry; this analysis included 130 cases of colorectal cancer (with available blood), which occurred between 1990 and April 30, 2002, and 260 matched controls. Baseline median CRP levels were ∼25% higher among colorectal cancer cases (3.4 mg/L) than controls (2.6 mg/L; P = 0.04). Relative to men in the lowest quartile of CRP concentration, men in the highest quartile had an odds ratio of 2.9 (95% confidence interval, 1.4-6.0) for developing colorectal cancer with a dose-response relationship supported (Ptrend = 0.006). The relation between CRP and incident colorectal cancer was modified by body mass index such that the association was stronger among lean individuals than in heavier individuals (Pinteraction = 0.018). These results support the notion that chronic low-grade inflammation is a marker for increased risk of colorectal cancer. (Cancer Res 2006; 66(4): 2483-7)
Ex vivoDetectable Human CD8 T-Cell Responses to Cancer-Testis Antigens
Authors: Baumgaertner Petra , Rufer Nathalie , Devevre Estelle , Derre Laurent , Rimoldi Donata , Geldhof Christine , Voelter Verena , Liénard Danielle , Romero Pedro , Speiser Daniel E.
Published: February 2006

Clinical trials have shown that strong tumor antigen–specific CD8 T-cell responses are difficult to induce but can be achieved for T-cells specific for melanoma differentiation antigens, upon repetitive vaccination with stable emulsions prepared with synthetic peptides and incomplete Freund's adjuvant. Here, we show in four melanoma patients that ex vivo detectable T-cells and thus strong T-cell responses can also be induced against the more universal cancer-testis antigens NY-ESO-1 and Mage-A10. Interestingly, all patients had ex vivo detectable T-cell responses against multiple antigens after serial vaccinations with three peptides emulsified in incomplete Freund's adjuvant. Antigen-specific T-cells displayed an activated phenotype and secreted IFNγ. The robust immune responses provide a solid basis for further development of human T-cell vaccination. (Cancer Res 2006; 66(4): 1912-6)
The Metastasis-Associated Gene CD24 Is Regulated by Ral GTPase and Is a Mediator of Cell Proliferation and Survival in Human Cancer
Authors: Smith Steven C. , Oxford Gary , Wu Zhong , Nitz Matthew D. , Conaway Mark , Frierson Henry F. , Hampton Garret , Theodorescu Dan
Published: February 2006

Ral GTPases are important mediators of transformation, tumorigenesis, and cancer progression. We recently identified the metastasis-associated protein CD24, a glycosyl phosphatidyl inositol–linked surface protein, as a downstream target of Ral signaling by profiling the expression of RalA/B–depleted bladder carcinoma cells. Because CD24 is highly expressed in bladder and many other tumor types, we sought to determine if this protein plays an essential role in maintaining the malignant phenotype. Here, we show that loss of CD24 function in cell lines derived from common tumor types is associated with decreased rates of cell proliferation, clonogenicity in soft agar, changes in the actin cytoskeleton, and induction of apoptosis. Given these phenotypes, we evaluated a human bladder cancer tissue microarray by immunohistochemistry for CD24 to determine if CD24 is a prognostic cancer biomarker. Multivariate analysis showed that increased CD24 expression correlated with shorter patient disease-free survival (P = 0.07). In conclusion, we show that CD24 is a novel and functionally relevant Ral-regulated target and a potentially important prognostic marker. We suggest that these insights may lead to future therapeutic approaches that seek to eliminate CD24 function in cancer cells. (Cancer Res 2006; 66(4): 1917-22)
Multiple Robust Signatures for Detecting Lymph Node Metastasis in Head and Neck Cancer
Authors: Roepman Paul , Kemmeren Patrick , Wessels Lodewijk F.A. , Slootweg Piet J. , Holstege Frank C.P.
Published: February 2006

Genome-wide mRNA expression measurements can identify molecular signatures of cancer and are anticipated to improve patient management. Such expression profiles are currently being critically evaluated based on an apparent instability in gene composition and the limited overlap between signatures from different studies. We have recently identified a primary tumor signature for detection of lymph node metastasis in head and neck squamous cell carcinomas. Before starting a large multicenter prospective validation, we have thoroughly evaluated the composition of this signature. A multiple training approach was used for validating the original set of predictive genes. Based on different combinations of training samples, multiple signatures were assessed for predictive accuracy and gene composition. The initial set of predictive genes is a subset of a larger group of 825 genes with predictive power. Many of the predictive genes are interchangeable because of a similar expression pattern across the tumor samples. The head and neck metastasis signature has a more stable gene composition than previous predictors. Exclusion of the strongest predictive genes could be compensated by raising the number of genes included in the signature. Multiple accurate predictive signatures can be designed using various subsets of predictive genes. The absence of genes with strong predictive power can be compensated by including more genes with lower predictive power. Lack of overlap between predictive signatures from different studies with the same goal may be explained by the fact that there are more predictive genes than required to design an accurate predictor. (Cancer Res 2006; 66(4): 2361-6)
Optical Imaging of Hydroxyapatite in the Calcified Vasculature of Transgenic Animals
Authors: Zaheer Atif , Murshed Monzur , De Grand Alec M. , Morgan Timothy G. , Karsenty Gerard , Frangioni John V.
Published: February 2006

Objective—

To detect the hydroxyapatite component of vascular calcification in vivo so that the process of calcium deposition can be studied in transgenic model systems.

Methods and Results—

We have previously developed a near-infrared fluorescent bisphosphonate derivative that binds with high affinity and specificity to hydroxyapatite, and an intraoperative near-infrared fluorescence imaging system for small animals. Using these tools, and a transgenic mouse strain with homozygous deletion of the matrix GLA protein (
Mgp
−/−
), we demonstrate that the hydroxyapatite component of vascular calcification can be detected in vivo with high sensitivity, specificity, and resolution.

Conclusions—

The hydroxyapatite component of vascular calcification can be detected optically, in real-time, without sacrifice of the animal. It is now possible to study the earliest events associated with vascular mineralization, at the cell and organ level, and to monitor the process in living animals.
Quantitative Trait Loci Modifying Cardiac Atrial Septal Morphology and Risk of Patent Foramen Ovale in the Mouse
Authors: Kirk Edwin P. , Hyun Changbaig , Thomson Peter C. , Lai Donna , Castro M. Leticia , Biben Christine , Buckley Michael F. , Martin Ian C.A. , Moran Chris , Harvey Richard P.
Published: February 2006

Atrial septal defect (ASD) is a common congenital heart disease (CHD) occurring in 5 to 7 per 10 000 live births. Mutations in 5 human genes (
NKX2.5
,
TBX5
,
GATA4
,
MYHC
,
ACTC
) are known to cause dominant ASD, but these account for a minority of cases. Human and mouse data suggest that ASD exists in an anatomical continuum with milder septal variants patent foramen ovale (PFO) and atrial septal aneurysm, strongly associated with ischemic stroke and migraine. We have previously shown in inbred mice that the incidence of PFO strongly correlates with length of the interatrial
septum primum
, defining a quantitative trait underlying PFO risk. To better understand genetic causation of atrial septal abnormalities, we mapped quantitative trait loci (QTL) influencing septal morphology using mouse strains (QSi5 and 129T2/SvEms) maximally informative for PFO incidence and 3 quantitative septal anatomical traits including
septum primum
length. [QSi5×129T2/SvEms]F2 intercross animals (n=1437) were phenotyped and a whole genome scan performed at an average 17-cM interval. Statistical methodology scoring PFO as a binary phenotype was developed as a confirmatory mapping technique. We mapped 7 significant and 6 suggestive QTL modifying quantitative phenotypes, with 4 supported by binary analysis. Quantitative traits, although strongly associated with PFO (
P
<0.001), correlated poorly with each other and in all but 1 case QTL for different traits were nonoverlapping. Thus, multiple anatomical processes under separate genetic control contribute to risk of PFO. Our findings demonstrate the feasibility of modeling the genetic basis of common CHD using animal genetic and genomic technologies.
Estrogen Receptor α Gene Variation Is Associated With Risk of Myocardial Infarction in More Than Seven Thousand Men From Five Cohorts
Authors: Shearman Amanda M. , Cooper Jackie A. , Kotwinski Paul J. , Miller George J. , Humphries Steve E. , Ardlie Kristin G. , Jordan Barbara , Irenze Kathryn , Lunetta Kathryn L. , Schuit Stephanie C. E. , Uitterlinden André G. , Pols Huibert A. P. , Demissie Serkalem , Cupples L. Adrienne , Mendelsohn Michael E. , Levy Daniel , Housman David E.
Published: February 2006

Understanding the mechanisms by which estrogens affect cardiovascular disease risk, including the role of variation in the gene for estrogen receptor α (
ESR1
), may be key to new treatment strategies. We investigated whether the
CC
genotype at
ESR1 c.454-397T
>
C
is associated with increased risk among men. Study of more than 7000 whites in 5 cohorts from 4 countries provided evidence that genotype
CC
, present in roughly 20% of individuals, is a risk factor for nonfatal acute myocardial infarction (odds ratio=1.44;
P
<0.0001), after adjustment for established cardiovascular risk factors. After exclusion of younger subjects from 2 cohorts, because of age interaction, the odds ratio increased (to 1.63).
Electrotonic Modulation of Cardiac Impulse Conduction by Myofibroblasts
Authors: Miragoli Michele , Gaudesius Giedrius , Rohr Stephan
Published: February 2006

Structural remodeling of the myocardium associated with mechanical overload or cardiac infarction is accompanied by the appearance of myofibroblasts. These fibroblast-like cells express α-smooth muscle actin (αSMA) and have been shown to express connexins in tissues other than heart. The present study examined whether myofibroblasts of cardiac origin establish heterocellular gap junctional coupling with cardiomyocytes and whether ensuing electrotonic interactions affect impulse propagation. For this purpose, impulse conduction characteristics (conduction velocity [θ] and maximal upstroke velocity [dV/dt
max
]) were assessed optically in cultured strands of cardiomyocytes, which were coated with fibroblasts of cardiac origin. Immunocytochemistry showed that cultured fibroblasts underwent a phenotype switch to αSMA-positive myofibroblasts that expressed connexin 43 and 45 both among themselves and at contact sites with cardiomyocytes. Myofibroblasts affected θ and dV/dt
max
in a cell density-dependent manner; a gradual increase of myofibroblast-to-cardiomyocyte ratios up to 7:100 caused an increase of both θ and dV/dt
max
, which was followed by a progressive decline at higher ratios. On full coverage of the strands with myofibroblasts (ratio >20:100), θ fell <200 mm/s. This biphasic dependence of θ and dV/dt
max
on myofibroblast density is reminiscent of “supernormal conduction” and is explained by a myofibroblast density-dependent gradual depolarization of the cardiomyocyte strands from −78 mV to −50 mV as measured using microelectrode recordings. These findings suggest that myofibroblasts, apart from their role in structural remodeling, might contribute to arrhythmogenesis by direct electrotonic modulation of conduction and that prevention of their appearance might represent an antiarrhythmic therapeutic target.
De Novo Synthesis of Cyclooxygenase-1 Counteracts the Suppression of Platelet Thromboxane Biosynthesis by Aspirin
Authors: Evangelista Virgilio , Manarini Stefano , Di Santo Angelo , Capone Marta L. , Ricciotti Emanuela , Di Francesco Luigia , Tacconelli Stefania , Sacchetti Andrea , D’Angelo Sandra , Scilimati Antonio , Sciulli Maria G. , Patrignani Paola
Published: February 2006

Aspirin affords cardioprotection through the acetylation of serine
529
in human cyclooxygenase-1 (COX-1) of anucleated platelets, inducing a permanent defect in thromboxane A
2
(TXA
2
)–dependent platelet function. However, heterogeneity of COX-1 suppression by aspirin has been detected in cardiovascular disease and may contribute to failure to prevent clinical events. The recent recognized capacity of platelets to make proteins de novo paves the way to identify new mechanisms involved in the variable response to aspirin. We found that in washed human platelets, the complete suppression of TXA
2
biosynthesis by aspirin, in vitro, recovered in response to thrombin and fibrinogen in a time-dependent fashion (at 0.5 and 24 hours, TXB
2
averaged 0.1±0.03 and 3±0.8 ng/mL; in the presence of arachidonic acid [10 μmol/L], it was 2±0.7 and 25±7 ng/mL, respectively), and it was blocked by translational inhibitors, by rapamycin, and by inhibitors of phosphatidylinositol 3-kinase. The results that COX-1 mRNA was readily detected in resting platelets and that [
35
S]-methionine was incorporated into COX-1 protein after stimulation strongly support the occurrence of de novo COX-1 synthesis in platelets. This process may interfere with the complete and persistent suppression of TXA
2
biosynthesis by aspirin necessary for cardioprotection.
Interobserver Agreement for the Bedside Clinical Assessment of Suspected Stroke
Authors: Hand Peter J. , Haisma Janneke A. , Kwan Joseph , Lindley Richard I. , Lamont Bart , Dennis Martin S. , Wardlaw Joanna M.
Published: February 2006

Background and Purpose—

Stroke remains primarily a clinical diagnosis, with information obtained from history and examination determining further management. We aimed to measure inter-rater reliability for the clinical assessment of stroke, with emphasis on items of history, timing of symptom onset, and diagnosis of stroke or mimic. We explored reasons for poor reliability.

Methods—

The study was based in an urban hospital with an acute stroke unit. Pairs of observers independently assessed suspected stroke patients. Findings from history, neurological examination, and the diagnosis of stroke or mimic, were recorded on a standard form. Reliability was measured by the κ statistic. We assessed the impact of observer experience and confidence, time of assessment, and patient-related factors of age, confusion, and aphasia on inter-rater reliability.

Results—

Ninety-eight patients were recruited. Most items of the history and the diagnosis of stroke were found to have moderate to good inter-rater reliability. There was agreement for the hour and minute of symptom onset in only 45% of cases. Observer experience and confidence improved reliability; patient-related factors of confusion and aphasia made the assessment more difficult. There was a trend for worse inter-rater reliability among patients assessed very early and very late after symptom onset.

Conclusions—

Clinicians should be aware that inter-rater reliability of the clinical assessment is affected by a variety of factors and is improved by experience and confidence. Our findings have implications for training of doctors who assess patients with suspected stroke and identifies the more reliable components of the clinical assessment.
Neuroprotective Effects of Activated Protein C Through Induction of Insulin-Like Growth Factor-1 (IGF-1), IGF-1 Receptor, and Its Downstream Signal Phosphorylated Serine-Threonine Kinase After Spinal Cord Ischemia in Rabbits
Authors: Yamauchi Takashi , Sakurai Masahiro , Abe Koji , Takano Hiroshi , Sawa Yoshiki
Published: February 2006

Background and Purpose—

Activated protein C (APC) has beneficial effects on ischemia reperfusion injury in neuron. However, the possible mechanism of such beneficial effects is not fully understood. The aim of this study was to investigate the effects and possible mechanisms of APC on ischemic spinal cord damage.

Methods—

After induction of spinal cord ischemia, APC (group A) or vehicle (group I) was injected intravenously. Severity of ischemic damage was analyzed by counting the number of motor neurons. To investigate the mechanisms by which APC prevents ischemic spinal cord damage, we performed immunoreactivity and Western blotting of insulin-like growth factor 1 (IGF-1), IGF-1 receptor, and phosphorylated serine-threonine kinase (p-Akt).

Results—

APC eased the functional deficits and increased the number of motor neurons after ischemia. Immunoreactivity of IGF-1 in group A was stronger than in group I at 8 hours after reperfusion but was at the same level at 1 day. Induction of IGF-1 receptor and the downstream factor p-Akt was stronger and more prolonged in group A.

Conclusions—

These results indicate that induction of IGF-1, IGF-1 receptor, and p-Akt might partially explain the neuroprotective effects of APC after transient spinal cord ischemia in rabbit.
MRI of Clot in Cerebral Venous Thrombosis
Authors: Idbaih Ahmed , Boukobza Monique , Crassard Isabelle , Porcher Raphaël , Bousser Marie-Germaine , Chabriat Hugues
Published: February 2006

Background and Purpose—

In cerebral venous thrombosis (CVT), the sensitivity of conventional MRI sequences to detect clot in the sinuses or veins is incomplete and largely depends on the time elapsed since thrombus formation. Little is known concerning the corresponding diagnostic value of fluid-attenuated inversion recovery (FLAIR), echo-planar T2* susceptibility-weighted imaging (T2*SW) or diffusion-weighted images (DWI).

Methods—

We performed a retrospective analysis of 114 MRI examinations from 39 patients with CVT using a structured assessment. The time course of sensitivity in the detection of clot (n=166 clots) was analyzed for different MR sequences using a multilevel logistic model. The sensitivity of different MR sequences for diagnosis of cortical venous thrombosis was tested separately (n=38 clots).

Results—

The sensitivity of T2*SW and T1-weighted spin echo image (T1SE) sequences to detect clot in the sinuses or veins was estimated at 90% and 71% between day 1 and day 3, which was much higher than that of T2SE, FLAIR or DWI during the first week of clinical onset. The sensitivity of T2*SW was stable in the first week. After this period, the sensitivity of T2*SW decreased less than that of T1SE. Thrombosed cortical veins, even in the absence of visible occlusion on magnetic resonance venography, were detected more frequently with T2*SW (97%) and T1SE (78%) than with FLAIR or DWI (<40%).

Conclusions—

T2*SW imaging appears to be of additional diagnostic value in CVT. The T2*SW sequence may be particularly useful during the acute phase of CVT when the sensitivity of the other sequences is incomplete and for the diagnosis of isolated cortical venous thrombosis.
Assessing Teacher Education
Authors: Darling-Hammond Linda
Published: February 2006

Productive strategies for evaluating outcomes are becoming increasingly important for the improvement, and even the survival, of teacher education. This article describes a set of research and assessment strategies used to evaluate program outcomes in the Stanford Teacher Education Program during a period of program redesign over the past 5 years. These include perceptual data on what candidates feel they have learned in the program (through surveys and interviews) as well as independent measures of what they have learned (data from pretests and posttests, performance assessments, work samples, employers’ surveys, and observations of practice). The article discusses the possibilities and limits of different tools for evaluating teachers and teacher education and describes future plans for assessing beginning teachers’ performance in teacher education, their practices in the initial years of teaching, and their pupils’ learning.
The Teacher Effectiveness Movement
Authors: Imig David G. , Imig Scott R.
Published: February 2006

The locus of control in teacher education has been outside the hands of those who educate our nation’s teachers for more than a century. Essentialists have long controlled the agenda for public schooling in America, and it is evident as well that their influence has prevailed in both the form and function of teacher education. The authors suggest that the contest between progressives and essentialists regarding teacher education has been repeatedly decided in favor of the essentialists. The current attempt to recast teacher education to focus singularly on effectiveness of classroom teachers in raising the test scores of their students is a not-unanticipated result of this enduring contest.
The Buffalo Upon the Chimneypiece
Authors: Fallon Daniel
Published: February 2006

Advocacy for academically based teacher education informs this article, which stresses the need for persuasive evidence of its value. A summary of the current state of the evidence is presented, concluding that positive evidence is now very limited. What is needed to make the case for academically based teacher education is quantitative empirical evidence. The data presented by Coleman are described as a case study to demonstrate the difficulties in interpreting empirical data developed through quantitative methods. The recent assembling of comprehensive longitudinal databases of student achievement in multiple knowledge domains linking individual students with specific teachers is shown to be a promising improvement available to contemporary researchers. Good data and the means for working with them are currently at hand. Those who support the aims of academically based teacher education are called to develop quantitative empirical arguments that will build a dossier of persuasive evidence on its behalf.
Structured Heterogeneity and Change in Laryngeal Phonetics
Authors: Purnell Thomas , Salmons Joseph , Tepeli Dilara , Mercer Jennifer
Published: February 2006

American sociolinguists have largely ignored obstruents as invariant, including how speakers distinguish /s, t/ from /z, d/. Upper Midwestern final obstruents provide clear evidence that the realization of such contrasts can and does vary. In a once German-speaking Wisconsin town, we have found that speakers systematically produce final laryngeal distinctions differently than reported for American English, with an apparent partial neutralization of the distinction. Here, we seek the historical antecedents of this pattern, comparing acoustic characteristics of recordings from speakers throughout the region born from 1866–1986. Analysis by date of birth shows distinct obstruent phonetics over this whole period, revealing striking changes in which acoustic cues have been exploited to maintain the distinction: The oldest speakers used primarily glottal pulsing, younger ones exhibit a “trading relation” between pulsing and preceding-vowel duration, and the youngest have reduced the acoustic cues of the distinction dramatically.