bluuebunny/crossref_metadata_2025 huggingface dataset:
Presentation Counts: Microenvironmental Regulation of Stem Cells by Biophysical and Material Cues
Authors: Keung Albert J. , Kumar Sanjay , Schaffer David V.
Published: October 2010

Stem cells reside in adult and embryonic tissues in a broad spectrum of developmental stages and lineages, and they are thus naturally exposed to diverse microenvironments or niches that modulate their hallmark behaviors of self-renewal and differentiation into one or more mature lineages. Within each such microenvironment, stem cells sense and process multiple biochemical and biophysical cues, which can exert redundant, competing, or orthogonal influences to collectively regulate cell fate and function. The proper presentation of these myriad regulatory signals is required for tissue development and homeostasis, and their improper appearance can potentially lead to disease. Whereas these complex regulatory cues can be challenging to dissect using traditional cell culture paradigms, recently developed engineered material systems offer advantages for investigating biochemical and biophysical cues, both static and dynamic, in a controlled, modular, and quantitative fashion. Advances in the development and use of such systems have helped elucidate novel regulatory mechanisms controlling stem cell behavior, particularly the importance of solid-phase mechanical and immobilized biochemical microenvironmental signals, with implications for basic stem cell biology, disease, and therapeutics.
Stochastic Mechanisms of Cell Fate Specification that Yield Random or Robust Outcomes
Authors: Johnston Robert J. , Desplan Claude
Published: October 2010

Although cell fate specification is tightly controlled to yield highly reproducible results and avoid extreme variation, developmental programs often incorporate stochastic mechanisms to diversify cell types. Stochastic specification phenomena are observed in a wide range of species and an assorted set of developmental contexts. In bacteria, stochastic mechanisms are utilized to generate transient subpopulations capable of surviving adverse environmental conditions. In vertebrate, insect, and worm nervous systems, stochastic fate choices are used to increase the repertoire of sensory and motor neuron subtypes. Random fate choices are also integrated into developmental programs controlling organogenesis. Although stochastic decisions can be maintained to produce a mosaic of fates within a population of cells, they can also be compensated for or directed to yield robust and reproducible outcomes.
Transmembrane Signaling Proteoglycans
Authors: Couchman John R.
Published: October 2010

Virtually all metazoan cells contain at least one and usually several types of transmembrane proteoglycans. These are varied in protein structure and type of polysaccharide, but the total number of vertebrate genes encoding transmembrane proteoglycan core proteins is less than 10. Some core proteins, including those of the syndecans, always possess covalently coupled glycosaminoglycans; others do not. Syndecan has a long evolutionary history, as it is present in invertebrates, but many other transmembrane proteoglycans are vertebrate inventions. The variety of proteins and their glycosaminoglycan chains is matched by diverse functions. However, all assume roles as coreceptors, often working alongside high-affinity growth factor receptors or adhesion receptors such as integrins. Other common themes are an ability to signal through their cytoplasmic domains, often to the actin cytoskeleton, and linkage to PDZ protein networks. Many transmembrane proteoglycans associate on the cell surface with metzincin proteases and can be shed by them. Work with model systems in vivo and in vitro reveals roles in growth, adhesion, migration, and metabolism. Furthermore, a wide range of phenotypes for the core proteins has been obtained in mouse knockout experiments. Here some of the latest developments in the field are examined in hopes of stimulating further interest in this fascinating group of molecules.
Paramutation and Development
Authors: Hollick Jay B.
Published: October 2010

Paramutation describes a heritable change of gene expression that is brought about through interactions between homologous chromosomes. Genetic analyses in plants and, more recently, in mouse indicate that genomic sequences related to transcriptional control and molecules related to small RNA biology are necessary for specific examples of paramutation. Some of the molecules identified in maize are also required for normal plant development. These observations indicate a functional relationship between the nuclear mechanisms responsible for paramutation and modes of developmental gene control.
Common Factors Regulating Patterning of the Nervous and Vascular Systems*
Authors: Melani Mariana , Weinstein Brant M.
Published: October 2010

The vascular and the nervous systems of vertebrates share many features with similar and often overlapping anatomy. The parallels between these two systems extend to the molecular level, where recent work has identified ever-increasing similarities between the molecular mechanisms employed in the specification, differentiation, and patterning of both systems. This review discusses some of the most recent literature on this subject, with particular emphasis on the roles that the Ephrin, Semaphorin, Netrin, and Slit signaling pathways play in vascular development.
Pathways for ATP release by bovine ciliary epithelial cells, the initial step in purinergic regulation of aqueous humor inflow
Authors: Li Ang , Leung Chi Ting , Peterson-Yantorno Kim , Mitchell Claire H. , Civan Mortimer M.
Published: October 2010

ATP release by nonpigmented (NPE) and pigmented (PE) ciliary epithelial cells is the enabling step in purinergic regulation of aqueous humor formation, but the release pathways are unknown. We measured ATP release from primary cultures of bovine mixed NPE and PE (bCE) cells and transformed bovine NPE and PE cells, using the luciferin-luciferase reaction. Hypotonicity-triggered bCE ATP release was inhibited by the relatively selective blocker of pannexin-1 (PX1) hemichannels (probenecid, 1 mM, 47 ± 2%), by a connexin inhibitor (heptanol, 1 mM, 49 ± 4%), and by an inhibitor of vesicular release (bafilomycin A1, 25 ± 2%), but not by the P2X7 receptor (P2RX7) antagonist KN-62. Bafilomycin A1 acts by reducing the driving force for uptake of ATP from the cytosol into vesicles. The reducing agent dithiothreitol reduced probenecid-blockable ATP release. Similar results were obtained with NPE and PE cell lines. Pannexins PX1–3, connexins Cx43 and Cx40, and P2RX7 were identified in native cells and cell lines by RT-PCR. PX1 mRNA expression was confirmed by Northern blots; its quantitative expression was comparable to that of Cx43 by real-time PCR. Heterologous expression of bovine PX1 in HEK293T cells enhanced swelling-activated ATP release, inhibitable by probenecid. We conclude that P2RX7-independent PX1 hemichannels, Cx hemichannels, and vesicular release contribute comparably to swelling-triggered ATP release. The relatively large response to dithiothreitol raises the possibility that the oxidation-reduction state is a substantial regulator of PX1-mediated ATP release from bovine ciliary epithelial cells.
Expression and role of serum and glucocorticoid-regulated kinase 2 in the regulation of Na+/H+exchanger 3 in the mammalian kidney
Authors: Pao Alan C. , Bhargava Aditi , Sole Francesca Di , Quigley Raymond , Shao Xinli , Wang Jian , Thomas Sheela , Zhang Jianning , Shi Mingjun , Funder John W. , Moe Orson W. , Pearce David
Published: October 2010

Serum and glucocorticoid-regulated kinase 2 (sgk2) is 80% identical to the kinase domain of sgk1, an important mediator of mineralocorticoid-regulated sodium (Na+) transport in the distal nephron of the kidney. The expression pattern and role in renal function of sgk2 are virtually uncharacterized. In situ hybridization and immunohistochemistry of rodent kidney coupled with real-time RT-PCR of microdissected rat kidney tubules showed robust sgk2 expression in the proximal straight tubule and thick ascending limb of the loop of Henle. Sgk2 expression was minimal in distal tubule cells with aquaporin-2 immunostaining but significant in proximal tubule cells with Na+/H+exchanger 3 (NHE3) immunostaining. To ascertain whether mineralocorticoids regulate expression of sgk2 in a manner similar to sgk1, we examined sgk2 mRNA expression in the kidneys of adrenalectomized rats treated with physiological doses of aldosterone together with the glucocorticoid receptor antagonist RU486. Northern blot analysis and in situ hybridization showed that, unlike sgk1, sgk2 expression in the kidney was not altered by aldosterone treatment. Based on the observation that sgk2 is expressed in proximal tubule cells that also express NHE3, we asked whether sgk2 regulates NHE3 activity. We heterologously expressed sgk2 in opossum kidney (OKP) cells and measured Na+/H+exchange activity by Na+-dependent cell pH recovery. Constitutively active sgk2, but not sgk1, stimulated Na+/H+exchange activity by >30%. Moreover, the sgk2-mediated increase in Na+/H+exchange activity correlated with an increase in cell surface expression of NHE3. Together, these results suggest that the pattern of expression, regulation, and role of sgk2 within the mammalian kidney are distinct from sgk1 and that sgk2 may play a previously unrecognized role in the control of transtubular Na+transport through NHE3 in the proximal tubule.
Modular Processing in the Hand Representation of Primate Primary Somatosensory Cortex Coexists With Widespread Activation
Authors: Reed Jamie L. , Qi Hui-Xin , Pouget Pierre , Burish Mark J. , Bonds A. B. , Kaas Jon H.
Published: October 2010

Neurons in the hand representation of primary somatosensory cortex (area 3b) are known to have discretely localized receptive fields; and these neurons form modules that can be visualized histologically as distinct digit and palm representations. Despite these indicators of the importance of local processing in area 3b, widespread interactions between stimuli presented to locations across the hand have been reported. We investigated the relationship of neuron firing rate with distance from the site of maximum activation in cortex by recording from a 100-electrode array with electrodes spaced 400 μm apart, implanted into the area 3b hand representation in anesthetized owl monkeys. For each stimulated location on the hand, the electrode site where neurons had the highest peak firing rate was defined as the peak activation site. The lesser firing rates of neurons at all other electrode sites in the grid were compared with the firing rates of neurons at the peak activation site. On average, peak firing rates of neurons decreased rapidly with distance away from the peak activation site. The effect of distance on the variance of firing rates was highly significant ( P < 0.0001). However, individual neurons retained high firing rates for distances over 3 mm. The clear decline in firing rate with distance from the most activated location indicates that local processing is emphasized in area 3b, while the distance of neurons with reduced but maintained firing rates ≤3–4 mm from the site of best activation demonstrated widespread activation in primary somatosensory cortex.
Physiological Basis for Inhibition of Morphine and Improgan Antinociception by CC12, a P450 Epoxygenase Inhibitor
Authors: Heinricher Mary M. , Maire Jennifer J. , Lee Delaina , Nalwalk Julia W. , Hough Lindsay B.
Published: October 2010

Many analgesic drugs, including μ-opioids, cannabinoids, and the novel nonopioid analgesic improgan, produce antinociception by actions in the rostral ventromedial medulla (RVM). There they activate pain-inhibiting neurons, termed “off-cells,” defined by a nociceptive reflex-related pause in activity. Based on recent functional evidence that neuronal P450 epoxygenases are important for the central antinociceptive actions of morphine and improgan, we explored the convergence of opioid and nonopioid analgesic drug actions in RVM by studying the effects of the P450 epoxygenase inhibitor CC12 on the analgesic drug-induced activation of these off-cells and on behavioral antinociception. In rats lightly anesthetized with isoflurane, we recorded the effects of intraventricular morphine and improgan, with and without CC12 pretreatment, on tail flick latency and activity of identified RVM neurons: off-cells, on-cells (pronociceptive neurons), and neutral cells (unresponsive to analgesic drugs). CC12 pretreatment preserved reflex-related changes in off-cell firing and blocked the analgesic actions of both drugs, without interfering with the increase in spontaneous firing induced by improgan or morphine. CC12 blocked suppression of evoked on-cell firing by improgan, but not morphine. CC12 pretreatment had no effect by itself on RVM neurons or behavior. These data show that the epoxygenase inhibitor CC12 works downstream from receptors for both μ-opioid and improgan, at the inhibitory input mediating the off-cell pause. This circuit-level analysis thus provides a cellular basis for the convergence of opioid and nonopioid analgesic actions in the RVM. A presynaptic P450 epoxygenase may therefore be an important target for development of clinically useful nonopioid analgesic drugs.
Easiness of Use and Validity Testing ofVS-SENSEDevice for Detection of Abnormal Vaginal Flora and Bacterial Vaginosis
Authors: Donders Gilbert G. G. , Marconi Camila , Bellen Gert
Published: October 2010

Accessing vaginal pH is fundamental during gynaecological visit for the detection of abnormal vaginal flora (AVF), but use of pH strips may be time-consuming and difficult to interpret. The aim of this study was to evaluate theVS-SENSEtest (Common Sense Ltd, Caesarea, Israel) as a tool for the diagnosis of AVF and its correlation with abnormal pH and bacterial vaginosis (BV). The study population consisted of 45 women with vaginal pH≥4.5 and 45 women with normal pH. Vaginal samples were evaluated byVS-SENSEtest, microscopy and microbiologic cultures. Comparing with pH strips results,VS-SENSEtest specificity was 97.8% and sensitivity of 91%. All severe cases of BV and aerobic vaginitis (AV) were detected by the test. Only one case with normal pH had an unclear result. Concluding,VS-SENSEtest is easy to perform, and it correlates with increased pH, AVF, and the severe cases of BV and AV.
Clinicopathologic Significance of HIF‐1α, CXCR4, and VEGF Expression in Colon Cancer
Authors: Wu Yugang , Jin Min , Xu Huanbai , Shimin Zhang , He Songbing , Wang Liang , Zhang Yanyun
Published: October 2010

We investigated the clinicopathologic significance of HIF‐1, CXCR4, and VEGF expression using immumohistochemistry in human colon cancer. HIF‐1, CXCR4, and VEGF high expression levels were correlated positively with TNM stage, lymph node involvement, and distant metastasis Furthermore, we found that combined high expression of any two of the three molecules (P = .028 for HIF‐1/CXCR4, P = .007 for HIF‐1/VEGF, and P = .004 for CXCR4/VEGF) had stronger correlation with lymph node metastasis than did each alone. However, a relationship with distant metastasis is seen only with the combinations CXCR4/VEGF (P = .069 for HIF‐1/CXCR4, P = .062 for HIF‐1/VEGF, and P = .035 for CXCR4/VEGF) as compared with those of single molecule high expression alone. Combined expression of all three molecules strongly correlates with lymph node metastasis and distant metastasis. The mRNA expression of HIF‐1, CXCR4, and VEGF were
quantified by real‐time PCR in different colon cancer tissue samples, the experiment results shown that fresh colon tissue samples significantly overexpressed CXCR4 and VEGF mRNA compared with negative control. Therefore, the disease‐free survival of all
patients after curative resection can be considered in association with all three markers expression.
Second‐Order Gauge‐Invariant Cosmological Perturbation Theory: Current Status
Authors: Nakamura Kouji
Published: October 2010

The current status of the recent developments of the second‐order gauge‐invariant cosmological perturbation theory is reviewed. To show the essence of this perturbation theory, we concentrate only on the universe filled with a single scalar field. Through this paper, we point out the problems which should be clarified for the further theoretical sophistication of this perturbation theory. We also expect that this theoretical sophistication will be also useful to discuss the theoretical predictions
of non‐Gaussianity in CMB and comparison with observations.
Frequency Invariant Beam Steering for Short-Pulse Systems with a Rotman Lens
Authors: Lambrecht Andreas , Laskowski Piotr , Beer Stefan , Zwick Thomas
Published: October 2010

A promising approach for beam steering of high-voltage transient signals for HPEM-systems (High Power Electro Magnetic) is presented. The inherent capability of the Rotman lens to provide true time delays is used to develop a prototype beam steering device for an antielectronics HPEM system in the frequency range from 350 MHz to 5 GHz. Results of analytical calculations, simulations, and measurements from a hardware prototype are presented. The detailed mechanical setup of the Rotman lens is presented. Additionally the output pulses are investigated when inputting a Gaussian-like transient signal. Then time domain measures of quality (full width at half maximum, ringing, delay spread, maximum of transfer function) are investigated for these output transients, and the simulation and measurement results are compared. A concluding analysis of the realizable time domain array pattern shows the radiated pulse form.
An ANFIS Approach for Real Power Transfer Allocation
Authors: Shareef Hussain , Abd Khalid Saifulnizam , Mustafa Mohd Wazir , Khairuddin Azhar
Published: October 2010

This paper proposes an adaptive neurofuzzy interface system (ANFIS) approach to identify the real power transfer between generators. Based on solved load flow results, it first uses modified nodal equation method (MNE) to determine real power contribution from each generator to loads. Then the results of MNE method and load flow information are utilized to train the designed ANFIS. It also incorporated an enhanced feature extraction method called principle component analysis (PCA) to reduce the input features to the ANFIS. The 25‐bus equivalent system of south Malaysia is utilized as a test system to illustrate the effectiveness of the ANFIS output compared to that of the MNE method. The ANFIS output provides promising results in terms of accuracy and computation time. Furthermore, it can be concluded that the ANFIS with enhanced feature extraction method reduces the time taken to train the ANFIS without affecting the accuracy of the results.
eIF2α Kinase PKR Modulates the Hypoxic Response by Stat3-Dependent Transcriptional Suppression of HIF-1α
Authors: Papadakis Andreas I. , Paraskeva Efrosyni , Peidis Philippos , Muaddi Hala , Li Suiyang , Raptis Leda , Pantopoulos Kostas , Simos George , Koromilas Antonis E.
Published: October 2010

Hypoxia within the tumor microenvironment promotes angiogenesis, metabolic reprogramming, and tumor progression. In addition to activating hypoxia-inducible factor-1α (HIF-1α), cells also respond to hypoxia by globally inhibiting protein synthesis via serine 51 phosphorylation of translation eukaryotic initiation factor 2α (eIF2α). In this study, we investigated potential roles for stress-activated eIF2α kinases in regulation of HIF-1α. Our investigations revealed that the double-stranded RNA–dependent protein kinase R (PKR) plays a significant role in suppressing HIF-1α expression, acting specifically at the level of transcription. HIF-1α transcriptional repression by PKR was sufficient to impair the hypoxia-induced accumulation of HIF-1α and transcriptional induction of HIF-1α–dependent target genes. Inhibition of HIF-1A transcription by PKR was independent of eIF2α phosphorylation but dependent on inhibition of the signal transducer and activator of transcription 3 (Stat3). Furthermore, HIF-1A repression required the T-cell protein tyrosine phosphatase, which acts downstream of PKR, to suppress Stat3. Our findings reveal a novel tumor suppressor function for PKR, which inhibits HIF-1α expression through Stat3 but is independent of eIF2α phosphorylation. Cancer Res; 70(20); 7820–9. ©2010 AACR.
Role of LIM and SH3 Protein 1 (LASP1) in the Metastatic Dissemination of Medulloblastoma
Authors: Traenka Christopher , Remke Marc , Korshunov Andrey , Bender Sebastian , Hielscher Thomas , Northcott Paul A. , Witt Hendrik , Ryzhova Marina , Felsberg Jörg , Benner Axel , Riester Stephanie , Scheurlen Wolfram , Grunewald Thomas G.P. , von Deimling Andreas , Kulozik Andreas E. , Reifenberger Guido , Taylor Michael D. , Lichter Peter , Butt Elke , Pfister Stefan M.
Published: October 2010

Medulloblastoma is the most common malignant pediatric brain tumor and is one of the leading causes of cancer-related mortality in children. Treatment failure mainly occurs in children harboring metastatic tumors, which typically carry an isochromosome 17 or gain of 17q, a common hallmark of intermediate and high-risk medulloblastoma. Through mRNA expression profiling, we identified LIM and SH3 protein 1 (LASP1) as one of the most upregulated genes on chromosome 17q in tumors with 17q gain. In an independent validation cohort of 101 medulloblastoma samples, the abundance of LASP1 mRNA was significantly associated with 17q gain, metastatic dissemination, and unfavorable outcome. LASP1 protein expression was analyzed by immunohistochemistry in a large cohort of patients (n = 207), and high protein expression levels were found to be strongly correlated with 17q gain, metastatic dissemination, and inferior overall and progression-free survival. In vitro experiments in medulloblastoma cell lines showed a strong reduction of cell migration, increased adhesion, and decreased proliferation upon LASP1 knockdown by small interfering RNA–mediated silencing, further indicating a functional role for LASP1 in the progression and metastatic dissemination of medulloblastoma. Cancer Res; 70(20); 8003–14. ©2010 AACR.
Impact of Stromal Sensitivity on Radiation Response of Tumors Implanted in SCID Hosts Revisited
Authors: García-Barros Mónica , Thin Tin Htwe , Maj Jerzy , Cordon-Cardo Carlos , Haimovitz-Friedman Adriana , Fuks Zvi , Kolesnick Richard
Published: October 2010

Severe combined immunodeficient (SCID) mice carry a germ-line mutation in DNA-PK, associated with deficiency in recognition and repair DNA double-strand breaks. Thus, SCID cells and tissues display increased sensitivity to radiation-induced postmitotic (clonogenic) cell death. Nonetheless, the single-radiation doses required for 50% permanent local control (TCD50) of tumors implanted in SCID mice are not significantly different from the TCD50 values of the same tumors in wild-type hosts. Whereas the tumor stroma is derived from the host, the observation that tumors implanted in SCID mice do not exhibit hypersensitivity to radiation might imply that stromal endothelial elements do not contribute substantially to tumor cure by ionizing radiation. Here, we challenge this notion, testing the hypothesis that ASMase-mediated endothelial apoptosis, which results from plasma membrane alterations, not DNA damage, is a crucial element in the cure of tumors in SCID mice by single-dose radiotherapy (SDRT). We show that the endothelium in MCA/129 fibrosarcomas and B16 melanomas exhibits a wild-type apoptotic phenotype in SCID hosts, abrogated in tumors in SCIDasmase−/− littermates, which also acquire resistance to SDRT. Conversion into a radioresistant tumor phenotype when implanted in SCIDasmase−/− hosts provides compelling evidence that cell membrane ASMase-mediated microvascular dysfunction, rather than DNA damage–mediated endothelial clonogenic lethality, plays a mandatory role in the complex pathophysiologic mechanism of tumor cure by SDRT, and provides an explanation for the wild-type SDRT responses reported in tumors implanted in SCID mice. Cancer Res; 70(20); 8179–86. ©2010 AACR.
Clld7, A Candidate Tumor Suppressor on Chromosome 13q14, Regulates Pathways of DNA Damage/Repair and Apoptosis
Authors: Zhou Xiaobo , Münger Karl
Published: October 2010

Chronic lymphocytic leukemia deletion gene 7 (Clld7) is a candidate tumor suppressor on chromosome 13q14. Clld7 encodes an evolutionarily conserved protein that contains an RCC1 domain plus broad complex, tramtrack, bric-a-brac (BTB), and POZ domains. In this study, we investigated the biological functions of Clld7 protein in inducible osteosarcoma cell lines. Clld7 induction inhibited cell growth, decreased cell viability, and increased γ-H2AX staining under conditions of caspase inhibition, indicating activation of the DNA damage/repair pathway. Real-time PCR analysis in tumor cells and normal human epithelial cells revealed Clld7 target genes that regulate DNA repair responses. Furthermore, depletion of Clld7 in normal human epithelial cells conferred resistance to apoptosis triggered by DNA damage. Taken together, the biological actions of Clld7 are consistent with those of a tumor suppressor. Cancer Res; 70(22); 9434–43. ©2010 AACR.
Multiple Injections of Electroporated Autologous T Cells Expressing a Chimeric Antigen Receptor Mediate Regression of Human Disseminated Tumor
Authors: Zhao Yangbing , Moon Edmund , Carpenito Carmine , Paulos Chrystal M. , Liu Xiaojun , Brennan Andrea L. , Chew Anne , Carroll Richard G. , Scholler John , Levine Bruce L. , Albelda Steven M. , June Carl H.
Published: October 2010

Redirecting T lymphocyte antigen specificity by gene transfer can provide large numbers of tumor-reactive T lymphocytes for adoptive immunotherapy. However, safety concerns associated with viral vector production have limited clinical application of T cells expressing chimeric antigen receptors (CAR). T lymphocytes can be gene modified by RNA electroporation without integration-associated safety concerns. To establish a safe platform for adoptive immunotherapy, we first optimized the vector backbone for RNA in vitro transcription to achieve high-level transgene expression. CAR expression and function of RNA-electroporated T cells could be detected up to a week after electroporation. Multiple injections of RNA CAR–electroporated T cells mediated regression of large vascularized flank mesothelioma tumors in NOD/scid/γc(−/−) mice. Dramatic tumor reduction also occurred when the preexisting intraperitoneal human-derived tumors, which had been growing in vivo for >50 days, were treated by multiple injections of autologous human T cells electroporated with anti-mesothelin CAR mRNA. This is the first report using matched patient tumor and lymphocytes showing that autologous T cells from cancer patients can be engineered to provide an effective therapy for a disseminated tumor in a robust preclinical model. Multiple injections of RNA-engineered T cells are a novel approach for adoptive cell transfer, providing flexible platform for the treatment of cancer that may complement the use of retroviral and lentiviral engineered T cells. This approach may increase the therapeutic index of T cells engineered to express powerful activation domains without the associated safety concerns of integrating viral vectors. Cancer Res; 70(22); 9053–61. ©2010 AACR.
Fecal DNA for Noninvasive Diagnosis of Colorectal Cancer in Immunochemical Fecal Occult Blood Test–Positive Individuals
Authors: Calistri Daniele , Rengucci Claudia , Casadei Gardini Andrea , Frassineti Giovanni Luca , Scarpi Emanuela , Zoli Wainer , Falcini Fabio , Silvestrini Rosella , Amadori Dino
Published: October 2010

Background: We aimed to define the potential of the fecal DNA assay as an alternative or in addition to the currently used immunochemical fecal occult blood test (iFOBT) for the early diagnosis of colorectal cancer.

Methods: A total of 560 individuals aged 50 to 69 years with a positive iFOBT were recruited from an Italian FOBT regional screening program. Twenty-six were diagnosed with adenocarcinoma, 264 with high-risk adenoma, and 54 with low-risk adenoma, whereas 216 subjects did not have premalignant or malignant lesions. Fecal DNA integrity was analyzed blindly by the fluorescence long DNA (FL-DNA) test.

Results: iFOBT and FL-DNA were largely independent variables (rs = 0.036, P = 0.42), with values ranging from 101 to 5,826 ng/mL and from 0 to 515 ng, respectively. Median values of both variables were significantly higher in cancer patients than in patients with noncancerous lesions or in healthy individuals. Moreover, iFOBT and FL-DNA values were individually associated with a number of pathologic parameters. Sequential use of the diagnostic iFOBT and FL-DNA methods showed that fecal DNA provided more accurate diagnostic information and was able to identify subgroups at different risk of cancer in iFOBT-positive individuals.

Conclusions: A combined approach based on FL-DNA and iFOBT evaluation could help to better identify colorectal cancers and to determine a patient's risk of harboring a preneoplastic or neoplastic lesion. Further evaluation in a screening setting is needed to confirm this hypothesis.

Impact: Fecal DNA could be a useful tool to better predict cancer risk in FOBT-positive individuals. Cancer Epidemiol Biomarkers Prev; 19(10); 2647–54. ©2010 AACR.
High Levels of Expression of Human Stromal Cell–Derived Factor-1 Are Associated with Worse Prognosis in Patients with Stage II Pancreatic Ductal Adenocarcinoma
Authors: Liang John J. , Zhu Shaobo , Bruggeman Richard , Zaino Richard J. , Evans Douglas B. , Fleming Jason B. , Gomez Henry F. , Zander Dani S. , Wang Huamin
Published: October 2010

Background: Stromal cell–derived factor-1 (SDF-1) and its receptor, CXCR4, have been shown to mediate invasiveness and metastatic behavior in a number of cancers, including ovarian, prostate, bladder, breast, and pancreatic cancers. The expression and significance of SDF-1 in pancreatic ductal adenocarcinoma (PDA) have not been systematically studied.

Methods: We examined the expression of SDF-1 by immunohistochemistry using a mouse anti-human SDF-1/CXCL12 antibody (dilution 1:300) and a tissue microarray consisting of 72 stage II PDAs from pancreaticoduodenectomy specimens. The staining results were categorized as SDF-1-high (SDF-1-H; cytoplasmic staining of ≥10% of tumor cells) or SDF-1-low (SDF-1-L; no staining or staining of <10% of tumor cells). The results of SDF-1 expression were correlated with clinicopathologic parameters and survival. Statistical analyses were done using SPSS software.

Result: Of the 72 stage II PDAs, 25 (35%) showed high levels of SDF-1 expression. The median overall and recurrence-free survival for patients with SDF-1-H PDAs were 26.1 and 11.1 months, respectively, compared with 44.3 and 22.3 months for patients with SDF-1-L tumors (log-rank test, P = 0.047 and P = 0.021). In multivariate analysis, high SDF-1 expression correlated with poor overall and disease-free survival (P = 0.02 and P = 0.02) independent of tumor size, differentiation, and lymph node status.

Conclusion: High levels of SDF-1 expression were associated with poor overall and disease-free survival in patients with stage II PDA. SDF-1 may serve as a useful prognostic marker for stage II PDA.

Impact: Our results suggest that SDF-1-CXCR4 or SDF-1-CXCR7 pathways may represent a potential target for therapeutic intervention as well as prediction of prognosis in PDA. Cancer Epidemiol Biomarkers Prev; 19(10); 2598–604. ©2010 AACR.
Reproductive Factors, Hormone Use, and Risk for Lung Cancer in Postmenopausal Women, the Nurses' Health Study
Authors: Baik Christina S. , Strauss Gary M. , Speizer Frank E. , Feskanich Diane
Published: October 2010

Background: There is increasing evidence suggesting that female hormones may play a significant role in lung cancer development. We evaluated the associations between reproductive factors, exogenous hormone use, and lung cancer incidence in the Nurses' Health Study.

Methods: We assessed age at menopause, age at menarche, type of menopause, parity, age at first birth, postmenopausal hormone (PMH) use, and past oral contraceptive use in 107,171 postmenopausal women. Cox models were used to estimate the hazard ratios for each exposure, adjusting for smoking and other covariates.

Results: We identified 1,729 lung cancer cases during follow-up from 1984 to 2006. Menopause onset before 44 years of age (hazard ratio, 1.39; 95% confidence interval, 1.14-1.70) and past oral contraceptive use for >5 years (hazard ratio, 1.22; 95% confidence interval, 1.05-1.42) were associated with increased lung cancer risk. These associations were strongest in current smokers and small cell histology. In never smokers, increased parity was associated with decreased risk among parous women (P trend = 0.03), whereas in current smokers, older age at first birth was associated with increased risk (P trend = 0.02). PMH use was not associated with overall lung cancer incidence. However, nonsignificant results of increased risk in adenocarcinoma were seen with current PMH use.

Conclusions: Our findings suggest female hormones may influence lung carcinogenesis, although the effect is likely modest, varied by histologic subtype, and altered by smoking.

Impact: Further investigation of the pathophysiology of female hormones in lung cancer subtypes and their interaction with smoking will lead to better understanding of lung carcinogenesis. Cancer Epidemiol Biomarkers Prev; 19(10); 2525–33. ©2010 AACR.
Effect of Long-term Storage in TRIzol on Microarray-Based Gene Expression Profiling
Authors: Ma Wencai , Wang Michael , Wang Zhi-Qiang , Sun Luhong , Graber David , Matthews Jairo , Champlin Richard , Yi Qing , Orlowski Robert Z. , Kwak Larry W. , Weber Donna M. , Thomas Sheeba K. , Shah Jatin , Kornblau Steven , Davis Richard E.
Published: October 2010

Background: Although TRIzol is widely used for preservation and isolation of RNA, there is suspicion that prolonged sample storage in TRIzol may affect array-based gene expression profiling (GEP) through premature termination during reverse transcription.

Methods: GEP on Illumina arrays compared paired aliquots (cryopreserved or stored in TRIzol) of primary samples of multiple myeloma (MM) and acute myeloid leukemia (AML). Data were analyzed at the “probe level” (a single consensus value) or “bead level” (multiple measurements provided by individual beads).

Results: TRIzol storage does not affect standard probe-level comparisons between sample groups: different preservation methods did not generate differentially expressed probes (DEP) within MM or AML sample groups, or substantially affect the many DEPs distinguishing between these groups. Differences were found by gene set enrichment analysis, but these were dismissible because of instability with permutation of sample labels, unbalanced restriction to TRIzol aliquots, inconsistency between MM and AML groups, and lack of biological plausibility. Bead-level comparisons found many DEPs within sample pairs, but most (73%) were <2-fold changed. There was no consistent evidence that TRIzol causes premature reverse transcription termination. Instead, a subset of DEPs were systematically due to increased signals in TRIzol-preserved samples from probes near the 5′ end of transcripts, suggesting better mRNA preservation with TRIzol.

Conclusions: TRIzol preserves RNA quality well, without a deleterious effect on GEP. Samples stored frozen with and without TRIzol may be compared by GEP with only minor concern for systematic artifacts.

Impact: The standard practice of prolonged sample storage in TRIzol is suitable for GEP. Cancer Epidemiol Biomarkers Prev; 19(10); 2445–52. ©2010 AACR.
Dietary Factors and Risk of Chronic Lymphocytic Leukemia and Small Lymphocytic Lymphoma: A Pooled Analysis of Two Prospective Studies
Authors: Tsai Huei-Ting , Cross Amanda J. , Graubard Barry I. , Oken Martin , Schatzkin Arthur , Caporaso Neil E.
Published: October 2010

Background: Other than male sex, family history, advanced age, and race, risk factors for chronic lymphocytic leukemia and small lymphocytic lymphoma (CLL/SLL) are unknown. Very few studies have investigated diet in relation to these leukemias, and no consistent associations are known.

Methods: Using two large prospective population-based studies, we evaluated the relationship between diet and CLL/SLL risk. Among 525,982 men and women free of cancer at enrollment, we identified 1,129 incident CLL/SLL cases during 11.2 years of follow-up.

Results: We found no associations between total fat, saturated fat, fiber, red meat, processed meat, fruit, or vegetable intake and risk of CLL/SLL. We noted a suggestive positive association between body mass index and CLL/SLL (hazard ratio, 1.30; 95% confidence interval, 0.99-1.36).

Conclusion: We did not find any associations between food or nutrient intake and CLL/SLL.

Impact: Our large prospective study indicates that diet may not play a role in CLL/SLL development. Cancer Epidemiol Biomarkers Prev; 19(10); 2680–4. ©2010 AACR.
Small Interfering RNA Targeting 14-3-3ζ Increases Efficacy of Chemotherapeutic Agents in Head and Neck Cancer Cells
Authors: Matta Ajay , DeSouza Leroi V. , Ralhan Ranju , Siu K.W. Michael
Published: October 2010

Patients diagnosed in advanced stages of head and neck squamous cell carcinoma often show limited response to chemotherapeutic agents. Recently, we reported the overexpression of 14-3-3ζ protein in head and neck premalignant and cancer tissues using liquid chromatography–tandem mass spectrometry with isotopic labeling and revealed its significance as a prognostic marker using immunohistochemical analysis. In this study, we determined the potential of 14-3-3ζ as a therapeutic target for head and neck cancer. Small interfering RNA (siRNA) targeting 14-3-3ζ was used to downregulate its expression in head and neck cancer cells in culture. Cell cycle analysis showed that head and neck cancer cells transfected with siRNA targeting 14-3-3ζ showed G2-M arrest. These siRNA transfectants also showed increased cell death on treatment with any one of the following chemotherapeutic agents: cisplatin, 5-fluorouracil, paclitaxel, or doxorubicin in comparison with the no transfection controls. Flow cytometric analysis using propidium iodide staining showed increased sub-G0 fraction in siRNA-transfected cells treated with any of these chemotherapeutic agents, suggesting cell death; in addition, Annexin V staining and terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling assay revealed increased apoptosis. Taken together, our results strongly showed that downregulation of 14-3-3ζ expression may serve to improve the sensitivity of head and neck cancer cells to chemotherapeutic agents. Mol Cancer Ther; 9(10); 2676–88. ©2010 AACR.
Aflibercept Exerts Antivascular Effects and Enhances Levels of Anthracycline ChemotherapyIn vivoin Human Acute Myeloid Leukemia Models
Authors: Lal Deepika , Park Jennifer A. , Demock Kellie , Marinaro Joseph , Perez Amanda M. , Lin Mei-Hui , Tian Lili , Mashtare Terry J. , Murphy Michael , Prey Joshua , Wetzler Meir , Fetterly Gerald J. , Wang Eunice S.
Published: October 2010

We examined whether potent vascular endothelial growth factor (VEGF) blockade mediated by aflibercept, a decoy VEGF receptor (VEGFR) 1/2 moiety with stronger affinity for VEGF than bevacizumab, resulted in antileukemia effects and enhanced the efficacy of systemic chemotherapy. The efficacy of aflibercept alone and in combination with doxorubicin was evaluated in human VEGF-expressing acute myeloid leukemia (AML) cell lines and primary cells xenotransplanted into immunodeficient mice. Aflibercept reduced primary VEGF/VEGFR-positive AML colony formation growth in vitro and inhibited AML xenograft growth up to 93% in association with antiangiogenic and antiproliferative effects, hypoxia, and VEGF sequestration in multiple models. High VEGF-A expression by AML cells promoted in vivo xenograft growth and aflibercept sensitivity. Aflibercept therapy slowed disease progression in two systemic human AML xenograft models and reduced peripheral leukemia disease in a primary relapsed AML model in NOD/SCID/IL2Rγnull mice. Combination aflibercept and doxorubicin enhanced antitumor effects in local xenograft models. Sequential aflibercept followed by doxorubicin resulted in progressive anthracycline accumulation in marrow and extramedullary AML sites and resulted in 2-fold higher drug levels 24 hours after administration. In contrast, tissues (tumor, plasma, marrow) treated with chemotherapy only showed progressive drug clearance over time. Combination aflibercept and doxorubicin also resulted in vascular narrowing, decreased vessel number, and perivascular apoptosis. These data suggest that inefficient drug delivery by leukemia-associated vasculature may mediate chemoresistance and support further clinical evaluation of combination aflibercept and anthracycline therapy in refractory/relapsed AML patients. Mol Cancer Ther; 9(10); 2737–51. ©2010 AACR.
Clinical Implications of the Influence of Ehm2 on the Aggressiveness of Breast Cancer Cells through Regulation of Matrix Metalloproteinase-9 Expression
Authors: Yu Hefen , Ye Lin , Mansel Robert E. , Zhang Yuxiang , Jiang Wen G.
Published: October 2010

Ehm2, a member of NF2/ERM/4.1 superfamily, has been indicated in disease progression and metastasis of prostate cancer. However, its function and implication in malignancies remain largely unknown. The present study aimed to examine the role of Ehm2 in breast cancer. We first constructed a hammerhead ribozyme transgene to knock down Ehm2 expression in breast cancer cells. The effect on growth, cell matrix adhesion, motility, and invasion following knockdown of Ehm2 was then investigated using in vitro models. Reduction of Ehm2 had inhibitory effects on in vitro growth and invasion of breast cancer cells. Flow cytometric analysis showed that knockdown of Ehm2 induced apoptosis. Knockdown of Ehm2 also significantly decreased matrix metalloproteinase 9 mRNA and protein levels, as well as the corresponding enzymatic activity, and consequently led to a reduction of the invasion. The expression pattern of Ehm2 in a cohort of breast specimens (normal, n = 33; cancer, n = 127) was analyzed using both quantitative real-time PCR and immunohistochemical staining. Increased expression of Ehm2 in breast cancer was seen at both mRNA and protein levels. Higher levels of Ehm2 transcripts were correlated with disease progression, metastasis, and poor prognosis. Disease-free survival of the patients with lower levels of Ehm2 was 135.8 (95% confidence interval, 125.1-146.5) months, significantly longer compared with 102.5 (95% confidence interval, 78.7-126.4) months of patients with higher levels of Ehm2 expression (P = 0.039). Taken together, increased Ehm2 expression correlates with poor prognosis and metastasis. Ehm2 may promote the invasive ability of breast cancer cells via regulation of matrix metalloproteinase 9. Mol Cancer Res; 8(11); 1501–12. ©2010 AACR.
Impaired ATP Kinetics in Failing In Vivo Mouse Heart
Authors: Gupta Ashish , Chacko Vadappuram P. , Schär Michael , Akki Ashwin , Weiss Robert G.
Published: October 2010

Background—

The hypothesis that the failing heart may be energy-starved is supported in part by observations of reduced rates of adenosine 5′-triphosphate (ATP) synthesis through the creatine kinase (CK) reaction, the primary myocardial energy reservoir, in patients with heart failure (HF). Although murine models have been used to probe HF pathophysiology, it has not been possible to noninvasively measure the rate of ATP synthesis through CK in the in vivo mouse heart. The purpose of this work was to exploit noninvasive spatially localized magnetic resonance spectroscopy techniques to measure ATP flux through CK in in vivo mouse hearts and determine the extent of any reductions in murine HF.

Methods and Results—

The Triple Repetition Time Saturation Transfer (TRiST) magnetic resonance spectroscopy method of measuring ATP kinetics was first validated in skeletal muscle, rendering similar results to conventional saturation transfer magnetic resonance spectroscopy. In normal mouse hearts, the in vivo CK pseudo–first-order-rate constant,

k
F

, was 0.32±0.03 s
−1
(mean±SD) and the rate of ATP synthesis through CK was 3.16±0.47 μmol/g/s. Thoracic aortic constriction reduced

k
F

by 31% (0.23±0.03 s
−1
,
P
<0.0001) and ATP synthesis through CK by 51% (1.54±0.25 μmol/g/s,
P
<0.0001), values analogous to those in failing human hearts.

Conclusions—

Despite the small size and high murine heart rate, the ATP synthesis rate through CK is similar in vivo in murine and human hearts and comparably reduced in HF. Because murine thoracic aortic constriction shares fundamental energetic similarities with human HF, this model and new magnetic resonance spectroscopy approach promise a powerful means to noninvasively probe altered energetics in HF.
Incidence and Contributors to Potential Drug‐Drug Interactions in Hospitalized Patients
Authors: Reimche Leanne , Forster Alan J. , van Walraven Carl
Published: October 2010

Drug‐drug interactions (DDIs) are drug combinations that result in pharmacological or clinical responses that differ from solitary administration. Previous studies of DDIs have been limited to particular drugs or particular patient populations. The authors performed a retrospective cohort study of all adults admitted to a teaching hospital between 1999 and 2005. All medications administered to patients were identified and compared with a standard reference of important DDIs. The authors measured the potential DDI incidence density as the percentage of time in the hospital during which patients were exposed to at least 1 DDI and used multivariate Poisson regression to determine its determinants. A total of 19.3% of 140 349 hospitalizations had at least 1 potential DDI. The potential DDI incidence density was 18.8%. Factors having the greatest influence on potential DDI incidence density included increased patient age (adjusted rate ratio patient >75 years vs <30 years, 2.25; 95% CI, 2.15–2.35), increased number of drug orders (adjusted rate ratio, 2.27 [2.23–2.30] for logarithm), and patient service (adjusted rate ratio, 1.49 [1.46–1.52] for surgical vs medical service). Potential DDIs were present during one fifth of hospitalization time.
Pharmacokinetics, Pharmacodynamics, and Safety of Ticagrelor in Volunteers With Mild Hepatic Impairment
Authors: Butler Kathleen , Teng Renli
Published: October 2010

Ticagrelor, a P2Y12 receptor antagonist that inhibits ADP‐induced platelet aggregation (IPA), has demonstrated improved outcomes in patients with acute coronary syndromes compared with clopidogrel. Because ticagrelor undergoes extensive hepatic elimination, this study evaluated the effect of mild hepatic impairment on its pharmacokinetics, pharmacodynamics, and safety. A single oral 90‐mg ticagrelor dose was administered to volunteers with and without hepatic impairment (10 with Child‐Pugh class A; 10 with normal liver function). Absorption of ticagrelor and formation of its active metabolite, AR‐C124910XX, were rapid in both groups. Ticagrelor exposure was higher in hepatically impaired volunteers (maximum concentration [Cmax] 12%; area under the plasma concentration‐time curve from time 0 to infinity [AUC] 23%) compared with controls. AR‐C124910XX exposure was also higher in hepatic impairment (Cmax 17%; AUC 66%). Ticagrelor is highly protein bound (>99.8%); the unbound fraction in plasma was comparable in volunteers with hepatic impairment and controls. Overall, IPA parameters were not significantly different between groups, and similar IPA‐concentration profiles were observed. Ticagrelor was well tolerated in both groups, and no adverse events were reported. In conclusion, mild hepatic impairment resulted in modestly higher exposure to ticagrelor and AR‐C124910XX, without subsequent effects on pharmacodynamics or tolerability Based on these data, no ticagrelor dosage adjustment is needed in patients with mild hepatic impairment.