bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of a Piping System Subjected to Thermal Stratification and Thermal Striping
Authors: Chattopadhyay Somnath
Published: January 2011

Piping systems in nuclear power plants are often designed for pressure and mechanical loadings (including seismic loads) and operating thermal transients. In the last few decades a number of failures have occurred due to thermal stratification caused by the mixing of hot and cold fluids under certain low flow conditions. Such stratified temperature fluid profiles give rise to circumferential metal temperature gradients through the pipe leading to high stresses causing fatigue damage. In this work, thermal stresses due to such temperature gradients have been calculated using a finite element method. The peak stresses calculated by this method has been used for fatigue evaluation. In addition the stresses due to thermal striping associated with stratification have also been independently assessed for high cycle fatigue. The method outlined in this paper is a simplified conservative procedure to obtain stratification stresses.
Analysis on Layer Cracking of Urea Reactors
Authors: Li Mengli , Wang Weiqiang , Liu Yan , Li Aiju , Song Mingda , Xu Shugen , Cui Yuliang , Yuan Xiao
Published: January 2011

A destructive explosion of a multilayered urea reactor on Mar. 21, 2005 in Shandong Province, China resulted in huge losses. About 10 urea reactors were scrapped in inspection and assessment after the explosion for the reason of layers severely cracking. Three scrapped urea reactors including the explosive reactor were anatomized layer by layer and 12 cracking reactors, and others were investigated for further study. Cracking morphology was observed in detail. Taking account of application conditions, the layer cracking can be divided into four categories: 1) severe cracking from the outmost layer inward, 2) severe cracking from the innermost layer outward, 3) randomly cracking from the outmost layer inward, or the innermost layer outward, or the middle layer, and 4) slight cracking. The reason for the layer cracking is SCC which is proved by means of visual observing the characteristics of the reactor cracking, metallographic experimenting on the samples taken from the cracking regions in the reactor and analyzing the corrosion products in the clearances between layers, the clearances of the cracks, and spills from air vent. The authors analyzed factors which caused different cracking categories from material, stress and media, gave advice on the leak detection of urea reactors: either the quality and flow of the leak detection steam should be strictly controlled, or better leak detection method should be used.
Evaluation of Leakage Probability of Non-Asbestos Fiber Sheet Gasket at Elevated Temperature Based on Percolation Theory
Authors: Hagihara Masahiro , Tsuji Hirokazu , Yamaguchi Atsushi
Published: January 2011

A long-term life prediction method for a compressed fiber sheet gasket under a high-temperature environment is studied. Non-asbestos compressed fiber sheet gaskets are now being used as a substitute for asbestos in the bolted flange joint, for instance petrochemical factories. Consequently, there is a real need for a technology to predict the lifetime of non-asbestos compressed fiber sheet gaskets quantitatively. In this report, the facing surface of the gasket and flange is visualized with scanning acoustic tomography (SAT). Voids were observed on the facing surface of the gasket and increased with the increase in exposure time at high temperature. If a leakage path for inner fluids is created by the increasing number of voids, the leak occurs on the facing surface of the gasket. The probability of a leak due to voids and the lifetime of this gasket are predicted by applying the percolation theory, which describes the connectedness of clusters.
Natural PWSCC Crack Growth in Dissimilar Metal Welds With Inlay
Authors: Brust F. W. , Shim D.-J. , Punch E. , Kalyanam S. , Rudland D.
Published: January 2011

The commercial nuclear power industry has proposed several mitigation techniques to address safety concerns due to primary water stress corrosion cracking (PWSCC) in nickel-based dissimilar metal (DM) welds (specifically Alloy 82/182 welds) in pressurized water reactors (PWRs). Since many of these welds reside in primary piping systems that have been approved for Leak-Before-Break (LBB), the mitigation strategies chosen must ensure that these systems still satisfy the LBB criteria. Mechanical Stress Improvement Process (MSIP), Full and Optimized Structural Weld Overlay (FSWOL, OWOL), and Inlay and Onlay cladding are examples of the currently proposed mitigation methods. This paper focuses on an evaluation of the inlay process for the mitigation of PWSCC since it may be the technique of choice for the large-diameter reactor coolant nozzles. Currently the ASME Section XI code is developing Code Case N-766 ‘Nickel Alloy Reactor Coolant Inlay and Cladding for Repair or Mitigation of PWR Full Penetration Circumferential Nickel Alloy Welds in Class 1 Items.’ This code case is documenting the procedures for applying inlay welds. The residual stresses caused by the inlay process were used to model the natural crack growth through the inlay in this paper. The inlay residual stresses and modeling methods are presented in a companion paper. Since the PWSCC crack growth rate is much slower in the inlay material (Alloy 52) compared with the Alloy 82/182 weld metal, the crack growth shape retains a ‘bubble’ appearance. This shape is a challenge to model within the framework of advanced finite element based natural crack growth methods. This paper focuses on the crack growth modeling challenges, the actual growth shapes for different weld repair and inlays processes, and finally compares crack growth rates to those made using a simple crack growth shape.
User’s Design Specification Recommendations for ASME Section VIII, Division 2
Authors: Seipp Trevor G. , George Shiju V. P.
Published: January 2011

The UDS (Users Design Specification) is the design-basis document for ASME Section VIII, Division 2 pressure vessels. It defines the vessel design requirements and serves as the single point of reference for the Manufacturer’s Design Report (MDR). Despite its importance, the authors’ have observed instances where insufficient attention has been paid to the creation of this baseline document. This paper discusses both requirements and recommended good practices for writing a UDS in accordance with the new Division 2 requirements. The work and information flow to arrive at the required and recommended information is discussed. In particular, the multi-disciplinary nature of a well-developed UDS and the importance of change management will be emphasized. Finally, formatting and other good practices will be discussed.
Development of a Blood Flow Model Including Hypergravity and Validation Against an Analytical Model
Authors: van Geel M. H. A. , Giannopapa C. G. , van der Linden B. J. , Kroot J. M. B.
Published: January 2011

Fluid structure interaction (FSI) appears in many areas of engineering, e.g. biomechanics, aerospace, medicine and other areas and is often motivated by the need to understand arterial blood flow. FSI plays a crucial role and cannot be neglected when the deformation of a solid boundary affects the fluid behavior and vice versa. This interaction plays an important role in the wave propagation in liquid filled flexible vessels. Additionally, the effect of hyper gravity under certain circumstances should be taken into account, since such exposure can cause alterations in the wave propagation underexposed. Typical examples in which hyper gravity occurs are rollercoaster rides and aircraft or spacecraft flights. This paper presents the development of an arterial blood flow model including hyper gravity. This model has been developed using the finite element method along with the ALE method. This method is used to couple the fluid and structure. In this paper straight and tapered aortic analogues are included. The obtained computational data for the pressure is compared with analytical data available.
Non Fracture Prediction of a C-Mn Weld Joint in Brittle to Ductile Fracture Transition Temperature Range
Authors: Chapuliot S. , Marie S. , N’Guyen T. H. , Niclaeys C. , Degalleix S.
Published: January 2011

This paper deals with the brittle fracture risk evaluation for a C-Mn weld joint in the upper shelf of the brittle to ductile fracture transition temperature range, with the main objective to develop a predictive criteria, able to demonstrate the complete absence of brittle fracture risk. The question was investigated in the frame of two PhDs. In the first one (V. Le Corre PhD), a critical stress based fracture criterion was proposed, qualibrated and validated against experimental data for the base metal. This work gave promising results with, in particular, the capability of the model to predict non fracture for a cracked pipe submitted to bending at low temperature. In the second one (T.H. N’Guyen PhD), the model was calibrated and applied to the weld joint. The work showed that material heterogeneity of the weld metal must be taken into account in order to obtain a good representation of the fracture behavior. Again, the model was confronted to different specimen geometries and showed its capability to reasonably predict constraint and geometrical effects on the brittle fracture appearance risk. The paper gives a synthesis of the main results obtained during these two PhDs, questions still to be solved and perspectives for the continuation of this work.
Characterization of NbAlO dielectric film deposited on InP
Authors: He Dawei , Cheng Xinhong , Xu Dawei , Wang Zhongjian , Yu Yuehui , Sun Qingqing , Zhang David Wei
Published: January 2011

In this work, NbAlO dielectric films were grown by atomic layer deposition method on InP substrate and were treated with rapid thermal annealing (RTA) process at 500 °C. Synchrotron radiation x-ray reflectivity measurements suggested that 1.5 nm interfacial layer exists at InP interface with a roughness of 0.4 nm. Synchrotron radiation x-ray diffraction showed that NbAlO film was polycrystal after RTA treatment. X-ray photoelectron spectra indicated that Nb–Al, Nb–O, and Al–O bonds existed. The electrical measurements indicated that the equivalent oxide thickness and the dielectric constant were 3.2 and 32 nm, respectively, and the leakage current density increased quickly from 0.6 to 15 mA/cm2 when gate bias changed from 1 to 4V.
Oxygen supply – a possible alternative
Authors: Barrand Keith
Published: January 2011

A supply of oxygen, both for the maintenance of anaesthesia using volatile anaesthetic agents and the support of animals requiring additional oxygen, is an essential part of modern veterinary practice. In most practices, this is provided via oxygen cylinders. In this article, Keith Barrand discusses an alternative – oxygen concentrators – with comparisons to cylinder oxygen use, where appropriate.
AN ANALYSIS OF ROUTE TO CHAOS FOR PIECEWISE SMOOTH SYSTEMS SUBMITTED TO NONSMOOTH TRANSITIONS
Authors: BENMERZOUK D. , BARBOT J. P.
Published: January 2011

In this paper, a mathematical analysis of a possible way to chaos (in the sense of Li and Yorke) for bounded piecewise smooth systems of dimension three submitted to nonsmooth transitions is proposed. This study is based on period doubling method applied to the relied Poincaré map defined on a Poincaré section chosen in the neighborhood of the bifurcation point and transverse to the switching manifold. This choice permits us to reduce the corresponding discrete system to dimension one and allows us to apply "period three implies chaos".
BIFURCATION CURVES OF A FAMILY OF ONE-DIMENSIONAL BIQUADRATIC POLYNOMIAL MAPS, DEPENDING ON THE COMPLEX VARIABLE, AND TWO REAL PARAMETERS
Authors: ISHIDA HISASHI , ITOH TSUYOSHI
Published: January 2011

Sun and Yin [2007] had presented a precise description of the connectedness locus of the family of real biquadratic polynomials {pa,b(z) = (z2 + a)2 + b}. We shall first give an elementary proof of their result. Second, we shall give a precise description of the sets of parameters (a, b) such that the family {pa,b} has attracting fixed points.
Lack of transketolase-like (TKTL) 1 aggravates murine experimental colitis
Authors: Bentz Susanne , Pesch Theresa , Wolfram Lutz , de Vallière Cheryl , Leucht Katharina , Fried Michael , Coy Johannes F. , Hausmann Martin , Rogler Gerhard
Published: January 2011

Transketolase-like (TKTL) 1 indirectly replenishes NADPH preventing damage induced by reactive oxygen species (ROS) formed upon intestinal inflammation. We investigated the function of TKTL1 during murine colitis and ROS detoxification for prevention of tissue damage. Mucosal damage in TKTL1−/− and wild-type (WT) mice was assessed by miniendoscopy and histology during dextran sodium sulfate (DSS) colitis. mRNA levels of interferon (IFN)-γ, inducible nitric oxide synthase (iNOS), interleukin (IL)-6, tumor necrosis factor (TNF), transketolase (TKT), and TKTL2 were determined by PCR and/or Western blotting. To assess oxidative and nitrosative stress nitrosylation, carbonylation and antioxidative enzymes catalase (Cat), superoxide dismutase 1 and 2, as well as glutathione (GSH) were determined. Myeloperoxidase (MPO) was determined for assessment of tissue neutrophils. TKTL1 knockout or DSS treatment did not influence TKT and TKTL2 mRNA or protein expression. Mucosal damage was significantly increased in TKTL1−/− mice indicated by miniendoscopy as well as a significantly shorter colon and more severe histological scores compared with WT mice during DSS colitis. This was associated with higher mRNA levels of IFN-γ, iNOS, IL-6, and TNF. In addition, iNOS protein expression was significantly enhanced in TKTL1−/− mice as well as MPO activity. Protein modification by nitric oxide (nitrotyrosine) was induced in TKTL1−/− mice. However, introduction of carbonyl groups by ROS was not induced in these mice. The expression of SOD1, SOD2, Cat, as well as GSH content was not significantly changed in TKTL1−/− mice. We conclude that induced colitis in TKTL1−/− mice was more severe compared with WT. This indicates a role of TKTL1 during mucosal repair and restoration.
Elastic and Thermal Dynamics in Femtosecond Laser-Induced Structural Change Inside Glasses Studied by the Transient Lens Method
Authors: Sakakura Masaaki , Terazima Masahide , Shimotsuma Yasuhiko , Miura Kiyotaka , Hirao Kazuyuki
Published: January 2011

A technique to study femtosecond laser induced structural change inside glasses, the transient lens (TrL) method, is described. Because the TrL method is sensitive to the refractive index change around the photoexcited region, the time dependence of the density, pressure, and temperature changes, which accompany refractive index change, can be monitored over a broad range of timescales. In the picosecond-nanosecond time range, the pressure wave generation was observed as an oscillating TrL signal. By comparing the TrL signal with that calculated based on thermoelastic simulation, the density, pressure, and temperature changes in the photoexcited region can be estimated. In the longer time range (nanoseconds—milliseconds), the thermal diffusion process was observed. By fitting the TrL signal with that simulated based on thermal diffusion, the temporal evolution of the temperature distribution was obtained. Based on these observations, the features of femtosecond laser-induced structural change inside glasses are revealed. The advantages of the TrL method are described.
Large Intra-Articular Anterior Cruciate Ligament Ganglion Cyst, Presenting with Inability to Flex the Knee
Authors: Sloane Jake , Gulati Vivek , Penna Sreeram , Pastides Philip , Baghla Davinder Paul Singh
Published: January 2011

A 41-year-old female presented with a 3-month history of gradually worsening anterior knee pain, swelling and inability to flex the knee. Magnetic resonance imaging (MRI) revealed a large intra-articular cystic swelling anterior to the anterior cruciate ligament (ACL), extending into the Hoffa's infrapatellar fat pad. Following manipulation under anaesthesia and arthroscopic debridement of the cyst, the patient's symptoms were relieved with restoration of normal knee motion. ACL ganglion cysts are uncommon intra-articular pathological entities, which are usually asymptomatic and diagnosed incidentally by MRI. This is the first reported case of an ACL cyst being so large as to cause a mechanical block to knee flexion.
Conceptual Engineering of CARA Fuel Element with Negative Void Coefficient for Atucha II
Authors: Lestani H. , Florido P. , González J.
Published: January 2011

Experimentally validated void reactivity calculations were used to study the feasibility of a change in the design basis of Atucha II Nuclear Power Plant including the Large LOCA event. The use of CARA fuel element with burnable neutronic absorbers and enriched uranium is proposed instead of the original fuel. The void reactivity, refuelling costs, and power peaking factors are analysed at conceptual level to optimize the burnable neutronic absorber, the enrichment grade, and their distribution inside the fuel. This work concludes that, for the considered plant conditions, either a void reactivity coefficient granting no prompt critical excursion on Large LOCA or negative void reactivity is achievable, with advantages on refuelling cost and linear power density.
Hamming Star-Convexity Packing in Information Storage
Authors: Shih Mau-Hsiang , Tsai Feng-Sheng
Published: January 2011

A major puzzle in neural networks is understanding the information encoding principles that implement the functions of the brain systems. Population coding in neurons and plastic changes in synapses are two important subjects in attempts to explore such principles. This forms the basis of modern theory of neuroscience concerning self-organization and associative memory. Here we wish to suggest an information storage scheme based on the dynamics of evolutionary neural networks, essentially reflecting the meta-complication of the dynamical changes of neurons as well as plastic changes of synapses. The information storage scheme may lead to the development of a complete description of all the equilibrium states (fixed points) of Hopfield networks, a space-filling network that weaves the intricate structure of Hamming star-convexity, and a plasticity regime that encodes information based on algorithmic Hebbian synaptic plasticity.
Abstract A1: Impact of CYP2D6∗10 and CYP3A5∗3 polymorphisms on the pharmacokinetics of tamoxifen in Asian breast cancer patients
Authors: Lim Joanne Siok Liu , Singh Onkar , Ng Raymond Chee Hui , Wong Nan Soon , Ramasamy Rathi Devi , Mahajan Anupama , Lee Edmund Jon Deoon , Chowbay Balram
Published: January 2011

Background: Tamoxifen (TAM) is a selective estrogen receptor modulator employed in the treatment of breast cancer. It is a prodrug with a complex metabolic pathway involving several phase I and II metabolic enzymes. TAM is metabolized by cytochrome P450 (CYP) enzymes to N-desmethyltamoxifen (NDM), 4-hydroxytamoxifen (4OHT) and endoxifen (END) with 4OHT and END being the active metabolites of TAM. CYP2D6 and CYP3A4/5 comprises the major CYP isoforms mediating the metabolism of TAM although other CYP isoforms also play a role. Polymorphisms present in genes encoding these CYP enzymes may influence the metabolism and pharmacokinetics of TAM and its metabolites.

Methods: A total of 116 Asian breast cancer patients were genotyped for CYP3A5∗3 polymorphism while 104 of these patients were genotyped for CYP2D6. Plasma levels of TAM and its 3 metabolites were obtained at steady state. The occurrence of hot flashes were monitored.

Results: The allelic frequencies of CYP2D6∗10 and CYP3A5∗3 in the breast cancer patients were 0.52 and 0.71, respectively. The plasma END level (median; range) of patients with CYP2D6∗10/∗10 (8.85; 6.27-34.68) was significantly lower compared to patients with CYP2D6∗1/∗1 (19.55; 4.18-42.56; pCYP2D6∗1/∗10 (16.18; 9.48-33.24; pCYP2D6∗10 was 359.02 ng/ml (124.7–590.65) and was significantly higher compared to patients with CYP2D6∗1/∗1 (239.27; 40.82-584.26; p=0.012). No associations were observed between the pharmacokinetics of TAM and CYP3A5∗3. Hot flashes, a common side-effect of TAM, occurred at an overall frequency of 0.208 in the patient population. Patients homozygous for the ∗10/∗10 genotype had the highest frequency of hot flashes compared to wild-type subjects (P>0.05).

Conclusion: This exploratory study identified CYP2D6∗10 to be an important predictor of TAM pharmacokinetics in Asian breast cancer patients. Other polymorphisms present in CYP2D6 or genes encoding other enzymes involved in metabolism of TAM may be useful in explaining inter-individual variation in TAM pharmacokinetics.

Citation Information: Clin Cancer Res 2010;16(7 Suppl):A1
Abstract A10: Upregulation of ADAM17 protease and HER ligands through a PKB negative feedback loop mediates acquired resistance to Trastuzumab in HER2 overexpressed breast cancer
Authors: Gijsen Merel , King Peter , Perera Tim , Parker Peter , Larijani Banafshe , Harris Adrian , Kong Anthony
Published: January 2011

The decision to treat breast cancer patients with Trastuzumab is based on HER2 receptor over-expression or gene amplification. However, even in this selective group of patients, the response rate remains poor and unpredictable. Furthermore, all responders eventually become resistant if Trastuzumab is given as monotherapy. It is still poorly understood how Trastuzumab exerts its mechanism of action and how the acquired resistance to this drug occurs. We have found the molecular mechanisms whereby Trastuzumab fails to abolish HER2 phosphorylation despite being an anti-HER2 monoclonal antibody and have resolved the inconsistencies in the literature regarding the effect of Trastuzumab on HER2 phosphorylation. Trastuzumab did not decrease HER2 phosphorylation in these cells despite the effect on HER2 receptor downregulation. HER2 phosphorylation was maintained by activation of EGFR, HER3 and HER4 via their dimerisation with HER2. The activation of EGFR, HER3 and HER4 was due to an upregulation of HER ligands including heregulin and betacellulin. The upregulation of HER ligands was mediated by ADAM17 through a PKB negative feedback loop. The feedback loop was activated because of the inhibition of PKB by Trastuzumab treatment since upregulation of HER ligands and ADAM17 also occurred when PKB phosphorylation was inhibited by a PKB inhibitor (Akt inhibitor VIII, Akti-1/2). However, the combination treatment of Trastuzumab with a panHER inhibitor JNJ-26483327 was able to abrogate the feedback loop and it was synergistic in tumour inhibition in a BT474 xenograft model. Our data provides evidence that Trastuzumab resistance can be mediated by activation of HER family ligands as a direct consequence of inhibition of HER2 and PKB signalling. This offers treatment opportunities for overcoming resistance in these patients, including approaches to target all HER receptors in combination with Trastuzumab treatment. Future research should utilize a systems biology approach to identify other feedback loops that may be involved in the acquired resistance to Trastuzumab treatment in HER2 positive breast cancer.

Citation Information: Clin Cancer Res 2010;16(7 Suppl):A10
Abstract A11: Phase II trial of letrozole (L), cyclophosphamide (C) and sorafenib (S) as neoadjuvant therapy in breast cancer patients (BC): Pharmacokinetic (PK) and pharmacodinamic (PD) analysis
Authors: Bazzola Letizia , Foroni Chiara , Andreis Daniele , Ferrozzi Francesco , Dogliotti Luigi , Berruti Alfredo , Fox Stephen B. , Harris Adrian L. , Generali Daniele , Bottini Alberto
Published: January 2011

Introduction: This trial assessed the PK and PD of letrozole-cyclophosphamide-sorafenib combination as neoadjuvant setting in patients (pts) with operable breast cancer (BC).

Methods: 13 estrogen receptor-positive postmenopausal BC pts with T2-4 N0-1 were enrolled to receive oral letrozole (L) 2.5 mg daily, 50 mg daily metronomic cyclophosphamide (C) and 400 mg twice daily sorafenib (S). S was introduced after 6 days of LC therapy. For PK analysis blood samples were collected on day 5 of cycle 1 and on day 1 of cycle 2 (day 29). At basal time and after 14 days, tumour size evaluation, Ki67 expression and MRI were performed.

Results: A significant reduction in Ki67 expression was observed in all the 13 patients after 14 days only (median 20.7% (range 3-36%) and 9.75% (range 0-20%) at 15th respectively, p<0.0001) with a concomitant reduction in tumour size detected by MRI (median 37 mm (range 15-90 mm) and 31 mm (range 13.4-90 mm) respectively, p=0.047). Three patients attained a partial response at MRI (RECIST criteria) after 15 days. The changes in ki67 expression did not correlate with changes in tumor size evaluated by MRI (Spearman r: −0.37). 10 patients out of 13 showed a clinical complete response at the end of the treatment. The most common drug-related grade 2 (G2) adverse events were skin rush (46%), hand-foot syndrome (46%), anorexia (38%), fatigue (15%), and G3 diarrhea (23%). Mean plasma concentrations of C were consistently lower following concomitant administrations of L, S and C compared to administration of L and C. This trend was confirmed by the comparison of corresponding AUC (0-24) and Cmax values from Day 5, Cycle 1 and Day 1 of Cycle 2. No influence was detected by co-administration with L.

Conclusions: These toxicity and PK results indicated that the combination feasible but sorafenib interpheres in non significant manner with the bioavailability of C. Moreover, the PD data indicated that the association of the already tested LC combination (Bottini at al, JCO 2006) with S is promising. A randomised study of LC vs LCS is ongoing.

Citation Information: Clin Cancer Res 2010;16(7 Suppl):A11
Abstract A14: Lack of tumor eradication of chemotherapy-sensitive BRCA1;p53-deficient mouse mammary tumors
Authors: Rottenberg Sven , Pajic Marina , Kersbergen Ariena , Banishki Nikola , Xu Guotai , Jonkers Jos , Borst Piet
Published: January 2011

Many breast cancers respond to chemotherapy or hormonal therapy, however, the lack of tumor eradication is a central clinical problem preceding the development of drug resistant tumors. We have previously studied responses of mammary tumors generated in the K14cre;Brca1F5-13/F5-13;p53F2-10/F2-10 mouse model for hereditary breast cancer to clinically relevant anti-cancer drugs such as doxorubicin, topotecan, cisplatin and the poly(ADP-ribose) polymerase (PARP) inhibitor olaparib (1-4). The BRCA1- and p53-deficient tumors generated in this model are hypersensitive to these drugs and never become resistant to cisplatin due to the large, irreversible deletion in Brca1 (5).

We show here that even dose-dense treatment with a maximum tolerable dose of cisplatin does not result in tumor eradication. This is not due to the trivial possibility that the drug-resistant remnants are poorly accessible to drug, since we found a homogeneous distribution of the platinum-DNA adducts throughout the tumor. To explain this result we have addressed the hypothesis that the lack of eradication of drug-sensitive tumors is due to increased in vivo chemotherapy resistance of tumor-initiating cells (TICs). Using the CD24 and CD49f cell surface markers which detect normal mouse mammary stem cells, we have identified TICs in BRCA1- and p53-deficient tumors. In addition to the Lin-/CD24+/CD49f+ subpopulation, we show that a larger population of Lin-/CD24+/CD49f-cells also has tumor-initiating capability in at least two serial orthotopic transplantations, suggesting that these are not more differentiated transit-amplifying cells. However, we did not find an enrichment of TICs in cisplatin-treated tumor remnants.

We conclude that in this model the resistance of cisplatin-surviving cells cannot be attributed to special biochemical defense mechanisms of TICs. Instead we will present data supporting the hypothesis that surviving TICs arrest in their cell cycle and ‘hibernate’ until the drug is gone. Using Brca1−/−;p53−/− cell lines derived from the mouse tumors we found that only Brca1−/−;p53−/− cells that were in the G0/G1 phase of the cell cycle 24h after cisplatin treatment were capable of forming new colonies, whereas cells in G2 or M were not. Hence, a p53-independent arrest in G0/G1 appears to underlie the lack of eradication of residual Brca1−/−;p53−/− cells.

Citation Information: Clin Cancer Res 2010;16(7 Suppl):A14
Abstract A17: miRNA silencing in malignant melanoma: Mechanisms, regulation, and potential implications
Authors: Leibowitz-Amit Raya , Zehavi Liron , Avni Dror , Sidi Yehezkel
Published: January 2011

Metastatic melanoma is a devastating disease with limited treatment options. miRNAs are small RNA species within cells whose aberrant expression has been implicated in cancerous transformation, in some cases by a mechanism of cellular de-differentiation. The role of miRNA in melanoma is still not known.

We recently observed that the expression of miRNAs from a large intergenic miRNA cluster is significantly down-regulated or absent in melanoma cell lines in comparison to normal melanocytes. This cluster resides within a parentally imprinted chromosomal region implicated in development and differentiation, and the miRNAs in this region are normally expressed selectively only in brain and skin. This chromosomal region was shown to be involved in the pathogenesis of ovarian carcinoma, and several of the miRNAs within it were shown to have tumor suppressor functions in other cellular models.

Our results demonstrate that in some melanoma cell lines, there is a chromosomal deletion or loss of heterozygosity in the cis-acting differentially-methylated regulatory region of this cluster. Conversely, in other cell lines we were able to re-express some of these miRNAs using epigenetic modifiers (de-methylating agents and histone de-acetylase inhibitors), suggesting that epigenetic aberrations take part in their silencing. We are now assessing whether miRNA re-expression or ectopic expression decreases the tumorigenic and metastatic potential of melanoma cells.

Our results suggest that aberrant regulation of this chromosomal region has a role in the pathogenesis of melanoma, and may even lead, in the future, to the development of new therapeutic strategies and bio-markers in this yet incurable disease.

Citation Information: Clin Cancer Res 2010;16(7 Suppl):A17
Abstract A20: Tumor selective delivery of chemotherapeutics via branched peptides
Authors: Falciani Chiara , Brunetti Jlenia , Lelli Barbara , Lozzi Luisa , Pini Alessandro , Ravenni Niccolò , Bencini Lapo , Menichetti Stefano , Moretti Renato , Bracci Luisa
Published: January 2011

Oligo-branched peptides, containing the sequence of the human regulatory peptide neurotensin (NT), have been used as specific tumor targeting agents, able to selectively and specifically deliver effector units for cell imaging or killing, to tumor cells that over-express NT receptors.

Tetra-branched peptides containing neurotensin (NT) sequence are described here as selective targeting agents for human colon, pancreas and prostate cancer. Fluorophore-conjugated peptides were used to measure tumor versus healthy tissue binding in human surgical samples, resulting in validation of neurotensin receptors as highly promising tumor-biomarkers. Drug-armed branched peptides were synthesized with different conjugation methods, resulting in uncleavable adducts or drug-releasing molecules. Human cell lines from colon (HT-29), pancreas (PANC-1) or prostate (PC-3) carcinoma were challenged with branched NT conjugated with 6-mercaptopurin, combretastain A-4, monastrol and 5-fluoro-deoxyuridine. Results indicated that branched NT conjugated with combretastain A-4 and 5-fluoro-deoxyuridine are the most active agents on HT-29 (EC50 1.1e-007 M) and PANC-1 (EC50 5.0e-007 M) respectively.

Tetra-branched NT armed with 5-FdU was used for in vivo experiments in HT-29-xenografted mice and produced a 50% reduction in tumor growth with respect to animals treated with the free drug. An unrelated branched peptide carrying the same drug was completely ineffective. In vitro and in vivo results indicated that branched peptides are valuable tools for tumor selective targeting.

The results reported in this presentation tell that branched-armed peptides are very promising pharmacodelivery options.

Citation Information: Clin Cancer Res 2010;16(7 Suppl):A20
Abstract A25: Humanized immunoenzyme with enhanced activity for glucuronide prodrug activation in the tumor microenvironment
Authors: Chen Kaichuan , Leu Yu-lin , Prijovich Zeljko M. , Roffler Steve
Published: January 2011

Antibody-directed enzyme prodrug therapy (ADEPT) is one of potential therapies to overcome systemic toxicity caused by traditional chemotherapy. Our lab have designed and developed glucuronide prodrugs that can be converted to potent antineoplastic agents by β-glucuronidase (βG). Toxic drugs can be preferentially generated at the tumor site after βG is first targeted to tumor cells as an antibody-enzyme fusion protein (immunoenzyme). For utilization of this therapeutic strategy in clinic, the immunoenzyme need to be compatible with humans. We have recently employed directed evolution to generate a human βG mutant (S2) that enhanced activity at neutral pH. To investigate if the S2 variant would be beneficial for tumor-selective prodrug activation, a humanized cc49 scFv gene with specificity for the TAG-72 tumor-associated antigen was fused to the wild-type hβG or S2 genes to create hcc49-hβG and hcc49-S2, respectively. Here, we show that immunoenzymes have 100-folds lower KD than hcc49 scFv and retain enzymatic activities as wild-type hβG and S2 mutant proteins. In in vitro cytotoxicity assay, the data demonstrated that hcc49 immunoenzymes can preferentially activate glucuronide prodrugs at TAG-72 positive cells, and hcc49-S2 was about 10-fold more effective than hcc49-hβG as indicated by a lower IC50 value. Further in vivo experiment, we will examine if the enhanced immunoenzyme have better efficacy to hydrolyze anticancer glucuronide prodrugs at physiological condition.

Citation Information: Clin Cancer Res 2010;16(7 Suppl):A25
Abstract A36: ImmunoSPECT and ImmunoPET imaging of IGF-1R expression in a model for triple negative breast cancer
Authors: Heskamp Sandra , Boerman Otto C. , Oyen Wim J.G. , Molkenboer-Kuenen Janneke D.M. , van der Graaf Winette T.A. , van Laarhoven Hanneke W.M.
Published: January 2011

Introduction: Triple negative breast cancer has a poor prognosis and chemotherapy is currently the mainstay of treatment. A potential new target for the treatment of triple negative breast cancer is the insulin-like growth factor 1 receptor (IGF-1R). Patients with triple negative breast cancer lesions that express the IGF-1R (30 to 40%) may be most suited to be treated with IGF-1R antibodies. Therefore, the aim of the present study was to develop a noninvasive, in vivo imaging method, using radiolabeled R1507, to visualize IGF-1R expression.

Material and methods: R1507, a monoclonal antibody directed against an epitope on the extracellular domain of the IGF-1R, was radiolabeled with 111Indium (111In), 125Iodine (125I) and 89Zirconium (89Zr). In vitro, the affinity and internalization kinetics of 111In-R1507 were determined using the IGF-1R expressing breast cancer cell line SUM149 (ER, PR and HER2 negative). In vivo studies were performed in BALB/c nude mice with subcutaneous SUM149 xenografts. To determine the pharmacodynamics of R1507, mice received an intravenous injection of 111In-R1507 and 125I-R1507. One, three and seven days post injection, mice were killed and ex vivo tumor uptake was measured. Non-specific uptake was determined by coinjection of an excess unlabeled R1507. A dose escalation study was performed with 111In-R1507 to determine the optimal protein dose of R1507 for in vivo imaging (dose range 1 – 1000 μg). Finally, SPECT and PET images were acquired of mice with subcutaneous SUM149 tumors one, three and seven days post injection of 111In-R1507 and 89Zr-R1507, respectively.

Results: 111In-R1507 (IC50 = 0.1 nM) was slowly internalized by SUM149 cells. 111In-R1507 specifically and efficiently accumulated in the SUM149 xenografts: the specific tumor uptake was 20% ID/g, 33% ID/g and 31% ID/g at one, three and seven days post injection, respectively. The dose escalation study showed that the optimal dose for imaging experiments was ≤ 3 μg (tumor uptake: 35% ID/g). MicroSPECT and microPET imaging of mice clearly visualized the subcutaneous SUM149 xenograft with increasing contrast at later time points.

Conclusion: 111In-R1507 SPECT and 89Zr-R1507 PET are excellent methods to visualize IGF-1R expression in vivo in triple negative breast cancer xenografts. In the future, these techniques may enable selection of patients with triple negative breast cancer for IGF-1R targeted therapy.

Citation Information: Clin Cancer Res 2010;16(7 Suppl):A36
Abstract A41: Somatic mutations in human cancer cell lines predict sorafenib response
Authors: Rhodes Daniel R. , Kaufmann Scott H. , Meng Xue Wei , Wyngaard Peter , Daubresse Gary , Leopold Judith S.
Published: January 2011

It is now widely accepted that a spectrum of somatic alterations occur in human cancer and that particular alterations are associated with response or lack of response to anti-cancer therapies. Here, we undertook a systematic correlation analysis of somatic mutations, copy number aberrations and drug response across 300+ human cancer cell lines. We studied the RAF and VEGFR inhibitor, sorafenib, evaluating associations between sorafenib response and somatic mutations in 35 common cancer genes and high-level amplifications and homozygous deletions in more than 100 minimal common regions of gain and loss, which include many known oncogenes and tumor suppressor genes. Notably, we found that NRAS mutations, among other alterations, were significantly associated with sensitivity to sorafenib (odds ratio = 7, p-value = 0.003), whereas activating BRAF mutations were strongly associated with a lack of response (odds ratio = 4.9, p-value = 0.012). Specifically, 64% (7 of 11) of NRAS mutant cell lines were sensitive to sorafenib, while only 20% (34 of 170) of NRAS wild-type lines were sensitive. On the contrary, just 6.7% (2 of 30) of BRAF mutant lines were sensitive to sorafenib. Because NRAS mutations occur frequently in leukemia and no leukemia cell lines were included in the original analysis, we selected 5 NRAS mutant and 5 NRAS wild-type leukemia cell lines for further evaluation. Consistent with our previous observation, the four most sensitive leukemia cell lines were all NRAS mutant, each line exhibiting greater than 50% growth inhibition after 72 hours of exposure to 4μM sorafenib. These results confirm the original association and suggest that across both solid tumors and hematologic malignancies, NRAS mutations may identify a subset of cancers that are likely to respond sorafenib. In addition, this work demonstrates that systematic analysis of somatic alterations and drug response across a large collection of cancer cell lines is capable of discovering novel predictive biomarkers.

Citation Information: Clin Cancer Res 2010;16(7 Suppl):A41
Abstract A42: The treatment of sporadic breast cancer with Poly(ADP-ribose) polymerase (PARP1) inhibitors (AZD2281, ABT888, AG14361) as single agents and in combination with chemotherapy
Authors: Fatima Naheed , Quick-Fountain Renee , De Soto Joseph A.
Published: January 2011

Introduction: It has been shown that poly(ADP-ribose) polymerase (PARP1) inhibitors may be useful in the treatment of BRCA1 and 2 hereditary breast cancers due to their deficiency in homologous repair. Many sporadic breast cancers may also be deficient in homologous repair due to deficiency's in RAD51, RAD54, DSS1, RPA1, NBS1, ATR, ATM, CH1, CHK2, FANCD2, FANCA, FANC or a down regulation of BRCA.

Methods: Human breast cancer cell lines representative of basal, Her2/neu, luminal A and luminal B subtypes were treated with PARP1 inhibitors alone or in combination with standard chemotherapeutic agents (alkylating, topoisomerase inhibitors, anti-metabolites, anti-mitotics and/or DNA intercalators) for 72 hours. IC50 values were determined by standard dose response curves of the PARP1) inhibitors (AZD2281, ABT888, AG14361), standard chemotherapeutic agents alone and in combination with each other. PARP1 inhibitor pharmacodynamic, PARP1 activity assays and the quantification of molecular markers from the apoptotic, DNA repair and mitotic pathways were also performed and correlated with IC50 values.

Results: There was no statistical difference in the IC50 of PARP1 inhibitors for BRCA1, non-BRCA1 triple negative or luminal human breast cancer tissue. Significant enhancement of chemotherapeutic cytotoxicity by PARP1 inhibitors was observed in not only hereditary (BRCA1 & BRCA2) breast cancer but, in sporadic breast cancer also. The results suggest that many sporadic breast cancers are deficient in homologous recombination and their ability to preserve DNA and chromosomal fidelity.

Conclusion: PARP1 inhibitors in combination with chemotherapy may be effective in treating sporadic breast cancer.

Citation Information: Clin Cancer Res 2010;16(7 Suppl):A42
Abstract A5: Characterization of signaling pathways related to resistance of breast cancer cells against irreversible EGFR/HER/ErbB kinase inhibitors
Authors: Bruenner-Kubath Caroline , Shabbir Waheed , Saferding Victoria , Wagner Renate , Singer Christian F. , Valent Peter , Berger Walter , Marian Brigitte , Zielinski Christoph C. , Grusch Michael , Grunt Thomas W.
Published: January 2011

Epidermal growth factor (EGF) receptor-related antigens (EGFR, ErbB1-4, HER1-4) represent emerging drug targets in oncology. However, resistance against ErbB-targeting drugs occurs frequently in cancer patients. Drug-resistant cells may exhibit drug-refractory phosphatidylinositol 3-kinase (PI3K) or mitogen-activated protein kinase (MAPK) signaling, but the relative impact and contribution of these two downstream pathways to drug resistance are still controversially discussed. We examined the effects of the two very potent, irreversibly binding ErbB receptor tyrosine kinase inhibitors (RTKIs) pelitinib (EKB-569) and canertinib (CI-1033) on PI3K- and MAPK activity in ErbB RTKI-sensitive and ErbB RTKI-resistant breast and ovarian cancer cells. Western blot analysis revealed that ErbB phosphorylation was abrogated by the inhibitors in both drug-sensitive and drug-resistant cells, whereas AKT- and GSK3β phosphorylation were drug-dependently downregulated only in drug-sensitive cells. ErbB RTKI sensitivity did not correlate with expression of wildtype PTEN or PIK3CA, nor was it associated with drug-dependent silencing of ERK1,2 in the breast and ovarian cancer cell lines examined. Moreover, exogenous AKT, but not MEK, significantly induced drug resistance. Our data demonstrate that blocking AKT phosphorylation is essential and sufficient, whereas abrogation of ERK phosphorylation is not required for ErbB RTKI anticancer efficacy. AKT phosphorylation may thus be a useful biomarker of ErbB RTKI sensitivity in breast and ovarian cancer cells. Supported by ‘MedizinischWissenschaftlicher Fonds des Bürgermeisters der Bundeshauptstadt Wien’ (#08037) and ‘Initiative Krebsforschung’, Medical Univ. Vienna.

Citation Information: Clin Cancer Res 2010;16(7 Suppl):A5
Abstract A8: GPNMB is an independent prognostic indicator of recurrence and a therapeutic target in triple negative breast cancer
Authors: Rose April , Grosset Andree-Anne , Dong Zhifeng , Bertos Nicholas , Simantov Ronit , Park Morag , Gaboury Louis , Siegel Peter
Published: January 2011

Purpose: While the murine orthologue of GPNMB (Glycoprotein non-metastatic B, DC-HIL, HGFIN), Osteoactivin, has been shown to promote breast cancer metastasis in an in vivo mouse model, its importance in human breast cancer is unknown. We have examined the significance of GPNMB expression as a prognostic indicator of recurrence and assessed its potential as a novel therapeutic target in breast cancer.

Experimental Design: The clinical significance of GPNMB expression in breast cancer was addressed by analyzing GPNMB mRNA levels in several published gene expression datasets and by determining GPNMB protein expression in two independent tissue microarrays derived from human breast tumors. Human breast cancer cell lines endogenously or exogenously expressing GPNMB were further used to validate a toxin-conjugated anti-GPNMB antibody as a novel therapeutic agent.

Results: GPNMB expression correlates with shorter times to recurrence and reduced overall survival of breast cancer patients. Epithelial-specific staining of GPNMB serves as an independent prognostic indicator for breast cancer recurrence. GPNMB is highly expressed in basal and triple-negative (TN) breast cancers and is associated with increased risk of recurrence within this subtype. GPNMB expression confers a more migratory and invasive phenotype on breast cancer cells. Treatment of mice harbouring endogenous GPNMB-expressing human breast cancer xenografts with CDX-011 (glembatumumab vedotin, CR011-vcMMAE), a GPNMB-targeted antibody-drug conjugate, induces and sustains tumor regression in vivo.

Conclusions: GPNMB expression is associated with the basal/TN subtype and is a prognostic marker of poor outcome in patients with breast cancer. CDX-011 (glembatumumab vedotin) is a promising new targeted therapy for patients with metastatic TN breast cancers, a patient population that currently lacks targeted-therapy options.

Citation Information: Clin Cancer Res 2010;16(7 Suppl):A8
Abstract B1: Heme oxygenase-1 transcription controlling GTn repeat polymorphism has contrary prognostic value in squamous cell carcinoma and adenocarcinoma of the esophagus
Authors: Effenberger Katharina E. , Vashist Yogesh K. , Uzungolu Guentac , Trump Florian , Kalinin Viacheslav , Bockhorn Maximilian , Brandt Burkhard , Pantel Klaus , Yekebas Emre F. , Izbicki Jakob R.
Published: January 2011

Purpose: The regulation of basal transcription of heme oxygenase-1 (HO-1) is dependent upon a GTn repeat polymorphism (GTn) in the promoter of the heme oxygenase-1 gene (HMOX-1). Here, we evaluate the role of GTn in surgically resected esophageal cancer patients without neoadjuvant or adjuvant treatment.

Patients and Methods: Genomic DNA was extracted from peripheral blood leucocytes of 297 patients. To determine the number of the GTn repeats DNA was amplified by RT-PCR and sequenced. The results were correlated with clinicopathological parameters, disseminated tumor cells (DTC) and clinical outcome.

Results: Three genotypes (SS, SL and LL) were defined based on cut-off points for short allele (“S”) with GTn repeats <25 and ≥25 as long allele (“L”). Throughout all analyses a contrary role of GTn was evident in squamous cell carcinoma (SCC) and adenocarcinoma (AC) patients. In SCC patients the SS genotype patients presented with less aggressive tumors in terms of tumor size, presence of regional and non-regional lymph node metastases, DTC and lower relapse rate compared to SL and LL genotype patients. In contrast, in AC patients the SS genotype patients displayed more aggressive tumor biology with bigger tumors, a higher rate of lymph node metastases, DTC as well as tumor recurrence compared to LL and SL genotype patients. The disease-free and overall survival in SCC patients was markedly reduced in LL genotypes compared to SL and SS genotypes. To the contrary, in AC the SS genotype patients displayed the worst disease-free and overall survival.

Conclusion: GTn was identified as an independent prognostic factor with contrary prognostic value for tumor recurrence and death in the two subtypes of esophageal cancer, SCC and AC.

Citation Information: Clin Cancer Res 2010;16(7 Suppl):B1