bluuebunny/crossref_metadata_2025 huggingface dataset:
Conifer-seed preferences of small mammals
Authors: Lobo N. , Duong M. , Millar J. S.
Published: September 2009

The preferences of the deer mouse ( Peromyscus maniculatus (Wagner, 1845)), southern red-backed vole ( Myodes gapperi (Vigors, 1830)), heather vole ( Phenacomys intermedius Merriam, 1889), long-tailed vole ( Microtus longicaudus (Merriam, 1888)), and meadow vole ( Microtus pennsylvanicus (Ord, 1851)) for lodgepole pine ( Pinus contorta Dougl. ex Loud.), white spruce ( Picea glauca (Moench.) Voss), and subalpine fir ( Abies lasiocarpa (Hook.) Nutt.) seeds were investigated using cafeteria-style feeding experiments. Seed selection by P. maniculatus and M. gapperi in the field was also studied. Peromyscus maniculatus, M. gapperi, M. longicaudus, and M. pennsylvanicus showed a distinct preference for lodgepole pine seeds and avoidance of subalpine fir seeds, and consumed the different species of seeds in similar relative proportions. Phenacomys intermedius behaved very differently from the other rodent species in that it did not show a preference among seed species, and consumed very few seeds in total. Findings from the field seed selection trials were consistent with laboratory results. We suggest that postdispersal seed predation by small mammals could limit the recruitment success of lodgepole pine and white spruce, but would not be a major problem in the regeneration of subalpine fir stands. This could provide an advantage for subalpine fir over neighbouring competitive species.
Role of visual barriers on mitigation of interspecific interference competition between native and non-native salmonid species
Authors: Hasegawa Koh , Maekawa Koji
Published: September 2009

Interspecific competition is a mechanism by which native salmonids can be replaced by non-native species. According to the two-species Lotka–Volterra competition model, replacement of the native species would occur when the non-native species has a competitive advantage over the native species and interspecific competition is more intense than competition within each of the two species. However, field observations have implied that visual barriers such as woody debris may slow down the replacement by mitigating interspecific competition. Using an experimental stream with white-spotted charr ( Salvelinus leucomaenis (Pallas, 1814)) as the native species and brown trout ( Salmo trutta L., 1758) as the non-native species, this study examined aggressive actions within and between species to assess the relative intensities of interspecific and intraspecific competitons within native species and the effect of visual barriers for reducing the relative intensity. In a sympatric and no-barrier treatment where trout was the dominant species, interspecific competition occurred more intensely than intraspecific competition among native charr. However, the relative intensity of interspecific competition decreased in a sympatric and with-barrier treatment. Our results suggest that interspecific competition may contribute to the replacement of native species by more competitive, non-native species. However, restoring visual barriers is a potential method to mitigate interference interactions and may deter the replacement.
Signaling through Accounting Accruals vs. Financial Policy: Evidence from Bank Loan Loss Provisions and Dividend Changes
Authors: Yang Dong-Hoon
Published: September 2009

This study examines substitution or complementarity relationships between discretionary loan loss provisions (LLP) and dividend signals. The statistical tests and results presented in this study indicate that bank managers may signal simultaneously with an accounting policy (i.e., discretionary LLP) and a financial policy (i.e., dividend change). This finding primarily points out the possibility that a bank manager with an incentive to mitigate asymmetric information can select multiple signals to maximize signaling effects. Thus, LLP signaling is a complementary (rather than a substitute) signaling device of dividend signaling.
A NEW BATCH IDENTIFICATION SCHEME
Authors: DEHKORDI MASSOUD HADIAN , ALIMORADI REZA
Published: September 2009

Identification protocols have a very important role in the world of electronic communication. In an identification protocol, the prover (user) proves to the verifier (center) that it is truly the authorized user who is communicating with the center. In one round of batch identification scheme a user with several secret keys (identities) can prove itself to the verifier instead of several proofs. In this paper, the first Weil pairing will be introduced. In addition, we propose a new batch zero-knowledge identification scheme based on the Weil pairing hereafter considered the security analysis of our proposed scheme.
Electrophysiological and Pharmacological Properties of Locomotor Activity-Related Neurons in cfos-EGFP Mice
Authors: Dai Yue , Carlin Kevin P. , Li Zongming , McMahon Douglas G. , Brownstone Robert M. , Jordan Larry M.
Published: September 2009

Although locomotion is known to be generated by networks of spinal neurons, knowledge of the properties of these neurons is limited. Using neonatal transgenic mice that express enhanced green fluorescent protein (EGFP) driven by the c-fos promoter, we visualized EGFP-positive neurons in spinal cord slices from animals that were subjected to a locomotor task or drug cocktail [ N-methyl-d-aspartate, serotonin (5-HT), dopamine, and acetylcholine (ACh)]. The activity-dependent expression of EGFP was also induced in dorsal root ganglion neurons with electrical stimulation of the neurons. Following 60–90 min of swimming, whole cell patch-clamp recordings were made from EGFP+ neurons in laminae VII, VIII, and X from slices of segments T12 to L4. The EGFP+ neurons ( n = 55) could be classified into three types based on their responses to depolarizing step currents: single spike, phasic firing, and tonic firing. Membrane properties observed in these neurons include hyperpolarization-activated inward currents (29/55), postinhibitory rebound (11/55), and persistent-inward currents (31/55). Bath application of 10–40 μM 5-HT and/or ACh increased neuronal excitability or output with hyperpolarization of voltage threshold and changes in membrane potential. 5-HT also increased input resistance, reduced the afterhyperpolarization (AHP), and induced membrane oscillations, whereas ACh reduced the input resistance and increased the AHP. In this study, we demonstrate a new way of identifying neurons active in locomotion. Our results suggest that the EGFP+ neurons are a heterogeneous population of interneurons. The actions of 5-HT and ACh on these neurons provide insights into the neuronal properties modulated by these transmitters for generation of locomotion.
Development of Multisensory Convergence in the Xenopus Optic Tectum
Authors: Deeg Katherine E. , Sears Irina B. , Aizenman Carlos D.
Published: September 2009

The adult Xenopus optic tectum receives and integrates visual and nonvisual sensory information. Nonvisual inputs include mechanosensory inputs from the lateral line, auditory, somatosensory, and vestibular systems. While much is known about the development of visual inputs in this species, almost nothing is known about the development of mechanosensory inputs to the tectum. In this study, we investigated mechanosensory inputs to the tectum during critical developmental stages (stages 42–49) in which the retinotectal map is being established. Tract-tracing studies using lipophilic dyes revealed a large projection between the hindbrain and the tectum as early as stage 42; this projection carries information from the Vth, VIIth, and VIIIth nerves. By directly stimulating hindbrain and visual inputs using an isolated whole-brain preparation, we found that all tectal cells studied received both visual and hindbrain input during these early developmental stages. Pharmacological data indicated that the hindbrain-tectal projection is glutamatergic and that there are no direct inhibitory hindbrain-tectal ascending projections. We found that unlike visual inputs, hindbrain inputs do not show a decrease in paired-pulse facilitation over this developmental period. Interestingly, over this developmental period, hindbrain inputs show a transient increase followed by a significant decrease in the α-amino-3-hydroxyl-5-methyl-4-isoxazolepropionate (AMPA)/N-methyl-d-aspartate (NMDA) ratio and show no change in quantal size, both in contrast to visual inputs. Our data support a model by which fibers are added to the hindbrain-tectal projection across development. Nascent fibers form new synapses with tectal neurons and primarily activate NMDA receptors. At a time when retinal ganglion cells and their tectal synapses mature, hindbrain-tectal synapses are still undergoing a period of rapid synaptogenesis. This study supports the idea that immature tectal cells receive converging visual and mechanosensory information and indicates that the Xenopus tectum might be an ideal preparation to study the early development of potential multisensory interactions at the cellular level.
Gene expression endpoints following chronic waterborne copper exposure in a genomic model organism, the zebrafish, Danio rerio
Authors: Craig Paul M. , Hogstrand Christer , Wood Chris M. , McClelland Grant B.
Published: September 2009

Although copper (Cu) is an essential micronutrient for all organisms, in excess, waterborne Cu poses a significant threat to fish from the cellular to population level. We examined the physiological and gene expression endpoints that chronic waterborne Cu exposure (21 d) imposes on soft-water acclimated zebrafish at two environmentally relevant concentrations: 8 μg/l (moderate) and 15 μg/l (high). Using a 16,730 65-mer oligonucleotide customized zebrafish microarray chip related to metal metabolism and toxicity to assess the transcriptomic response, we found that 573 genes in the liver responded significantly to Cu exposure. These clustered into three distinct patterns of expression. There was distinct upregulation of a majority of these genes under moderate Cu exposure and a significant downregulation under high Cu exposure. Microarray results were validated by qPCR of eight genes; two genes, metallothionein 2 (mt2) and Na+-K+-ATPase 1a1 (atp1a1), displayed increased expression under both Cu exposures, indicative of potential genetic endpoints of Cu toxicity, whereas the remaining six genes demonstrated opposing effects at each Cu exposure. Na+-K+-ATPase enzyme activity decreased during Cu exposure, which may be linked to Cu's competitive effects with Na+. Whole body cortisol levels were significantly increased in Cu-exposed fish, which prompted an analysis of the promoter region of all significantly regulated genes for glucocorticoid (GRE) and metal (MRE) response elements to dissociate metal- and stress-specific gene responses. Of the genes significantly regulated, 30% contained only a GRE sequence, whereas 2.5% contained only a consensus MRE. We conclude that the indirect effects of Cu exposure regulate gene expression to a much greater degree than the direct effects.
Quantitative trait loci for exercise training responses in FVB/NJ and C57BL/6J mice
Authors: Massett Michael P. , Fan Ruzong , Berk Bradford C.
Published: September 2009

The genetic factors determining the magnitude of the response to exercise training are poorly understood. The aim of this study was to identify quantitative trait loci (QTL) associated with adaptation to exercise training in a cross between FVB/NJ (FVB) and C57BL/6J (B6) mice. Mice completed an exercise performance test before and after a 4-wk treadmill running program, and changes in exercise capacity, expressed as work (kg·m), were calculated. Changes in work in F2mice averaged 1.51 ± 0.08 kg·m (94.3 ± 7.3%), with a range of −1.67 to +4.55 kg·m. All F2mice ( n = 188) were genotyped at 20-cM intervals with 103 single nucleotide polymorphisms (SNPs), and genomewide linkage scans were performed for pretraining, posttraining, and change in work. Significant QTL for pretraining work were located on chromosomes 14 at 4.0 cM [3.72 logarithm of odds (LOD)] and 19 at 34.4 cM (3.63 LOD). For posttraining work significant QTL were located on chromosomes 3 at 60 cM (4.66 LOD) and 14 at 26 cM (4.99 LOD). Suggestive QTL for changes in work were found on chromosomes 11 at 44.6 cM (2.30 LOD) and 14 at 36 cM (2.25 LOD). When pretraining work was used as a covariate, a potential QTL for change in work was identified on chromosome 6 at 68 cM (3.56 LOD). These data indicate that one or more QTL determine exercise capacity and training responses in mice. Furthermore, these data suggest that the genes that determine pretraining work and training responses may differ.
Oncogenesis Caused by Loss of the SNF5 Tumor Suppressor Is Dependent on Activity of BRG1, the ATPase of the SWI/SNF Chromatin Remodeling Complex
Authors: Wang Xi , Sansam Courtney G. , Thom Christopher S. , Metzger Daniel , Evans Julia A. , Nguyen Phuong T.L. , Roberts Charles W.M.
Published: September 2009

Alterations in chromatin play an important role in oncogenic transformation, although the underlying mechanisms are often poorly understood. The SWI/SNF complex contributes to epigenetic regulation by using the energy of ATP hydrolysis to remodel chromatin and thus regulate transcription of target genes. SNF5, a core subunit of the SWI/SNF complex, is a potent tumor suppressor that is specifically inactivated in several types of human cancer. However, the mechanism by which SNF5 mutation leads to cancer and the role of SNF5 within the SWI/SNF complex remain largely unknown. It has been hypothesized that oncogenesis in the absence of SNF5 occurs due to a loss of function of the SWI/SNF complex. Here, we show, however, distinct effects for inactivation of Snf5 and the ATPase subunit Brg1 in primary cells. Further, using both human cell lines and mouse models, we show that cancer formation in the absence of SNF5 does not result from SWI/SNF inactivation but rather that oncogenesis is dependent on continued presence of BRG1. Collectively, our results show that cancer formation in the absence of SNF5 is dependent on the activity of the residual BRG1-containing SWI/SNF complex. These findings suggest that, much like the concept of oncogene addiction, targeted inhibition of SWI/SNF ATPase activity may be an effective therapeutic approach for aggressive SNF5-deficient human tumors. [Cancer Res 2009;69(20):8094–101]
Circulating Tumor Cells Are Transcriptionally Similar to the Primary Tumor in a Murine Prostate Model
Authors: Helzer Kimberly T. , Barnes Helen E. , Day Laura , Harvey Jeanne , Billings Paul R. , Forsyth Allyn
Published: September 2009

The abundance of circulating tumor cells (CTC) indicates patient prognosis. Molecular characterization of CTCs may add additional information about a patient's disease. However, currently available methods are limited by contamination with blood cells. We describe a study using a modified CTC-chip to capture CTCs from an orthotopic xenograft model. Using laser capture microscopy to collect CTCs from the chip, we compared transcripts from purified CTCs with those from primary and metastatic tissue. Transcriptional profiles showed strong concordance among primary, metastatic, and CTC sources. Moreover, cells captured on the chip were viable and could be expanded in culture. We conclude that the CTC-chip is a useful tool to further characterize animal models of cancer and that viable CTCs can be isolated and show transcriptional similarity to solid tumors. [Cancer Res 2009;69(19):7860–6]
Dual Phosphoinositide 3-Kinase/Mammalian Target of Rapamycin Blockade Is an Effective Radiosensitizing Strategy for the Treatment of Non–Small Cell Lung Cancer Harboring K-RAS Mutations
Authors: Konstantinidou Georgia , Bey Erik A. , Rabellino Andrea , Schuster Katja , Maira Michael S. , Gazdar Adi F. , Amici Augusto , Boothman David A. , Scaglioni Pier Paolo
Published: September 2009

Non–small cell lung cancer (NSCLC) is a leading cause of cancer-related death worldwide. NSCLC often harbors oncogenic K-RAS mutations that lead to the aberrant activation of several intracellular networks including the phosphoinositide 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling pathway. Oncogenic K-RAS predicts poor prognosis and resistance to treatment with ionizing radiation (IR). Oncogenic K-Ras expression in the respiratory epithelium is sufficient to initiate NSCLC tumorigenesis, which requires the catalytic subunit of PI3K. Thus, effective inhibition of the PI3K signaling should lead to significant antitumor effects. However, therapy with rapamycin analogues has yielded disappointing results due in part to compensatory up-regulation of AKT. We hypothesized that dual PI3K/mTOR blockade would overcome these limitations. We tested this hypothesis with BEZ235, a novel dual PI3K/mTOR inhibitor that has recently entered clinical development. We found that BEZ235 induces a striking antiproliferative effect both in transgenic mice with oncogenic K-RAS–induced NSCLC and in NSCLC cell lines expressing oncogenic K-RAS. We determined that treatment with BEZ235 was not sufficient to induce apoptosis. However, we found that dual PI3K/mTOR blockade effectively sensitizes NSCLC expressing oncogenic K-RAS to the proapoptotic effects of IR both in vitro and in vivo. We conclude that dual PI3K/mTOR blockade in combination with IR may benefit patients with NSCLC expressing oncogenic K-RAS. These findings may have general applicability in cancer therapy, because aberrant activation of PI3K occurs frequently in human cancer. [Cancer Res 2009;69(19):7644–52]
Induction of Prostatic Intraepithelial Neoplasia and Modulation of Androgen Receptor by ETS Variant 1/ETS-Related Protein 81
Authors: Shin Sook , Kim Tae-Dong , Jin Fang , van Deursen Jan M. , Dehm Scott M. , Tindall Donald J. , Grande Joseph P. , Munz Jan-Marie , Vasmatzis George , Janknecht Ralf
Published: September 2009

ETS variant 1 (ETV1), also known as ETS-related protein 81, is overexpressed in prostate tumors, but whether and how this transcription factor affects tumorigenesis has remained elusive. Here, we show that ETV1 is primarily overexpressed in the most aggressive human prostate tumors. Transgenic ETV1 mice developed prostatic intraepithelial neoplasia as well as hyperplasia/neoplasia in seminal vesicles. Moreover, ETV1 cooperated with the androgen receptor (AR) to bind to the prostate-specific antigen enhancer and stimulate gene transcription. Consistent with its ability to physically interact with AR, ETV1 rendered an ETV1 binding site–driven reporter androgen inducible, and, on the other hand, ETV1 superinduced transcription from an AR binding site on androgen stimulation. In conclusion, our study substantiates that ETV1 overexpression is an underlying cause in the development of prostate and possibly also seminal vesicle cancer. Its interaction with and activation of AR provides a molecular mechanism on how ETV1 exerts its deleterious function. Thus, inhibiting ETV1 or blocking its interaction with AR may represent novel strategies in prostate cancer therapy. [Cancer Res 2009;69(20):8102–10]
Design of Agonistic Altered Peptides for the Robust Induction of CTL Directed towards H-2Db in Complex with the Melanoma-Associated Epitope gp100
Authors: van Stipdonk Marianne J.B. , Badia-Martinez Daniel , Sluijter Marjolein , Offringa Rienk , van Hall Thorbald , Achour Adnane
Published: September 2009

Immunogenicity of tumor-associated antigens (TAA) is often weak because many TAA are autoantigens for which the T-cell repertoire is sculpted by tolerance mechanisms. Substitutions at main anchor positions to increase the complementarity between the peptide and the MHC class I (MHC-I) binding cleft constitute a common procedure to improve binding capacity and immunogenicity of TAA. However, such alterations are tailored for each MHC-I allele and may recruit different CTL specificities through conformational changes in the targeted peptides. Comparative analysis of substituted melanoma-differentiation antigen gp100 in complex with H-2Db revealed that combined introduction of glycine and proline residues at the nonanchor positions 2 and 3, respectively, resulted in an agonistic altered peptide with dramatically enhanced binding affinity, stability, and immunogenicity of this TAA. Peptide vaccination using the p2Gp3P-altered peptide version of gp100 induced high frequencies of melanoma-specific CTL in the endogenous CD8+ repertoire. Crystal structure analysis of MHC/peptide complexes revealed that the conformation of the modified p2Gp3P-peptide was similar to the wild-type peptide, and indicated that this mimotope was stabilized through interactions between peptide residue p3P and the tyrosine residue Y159 that is conserved among most known MHC-I molecules throughout mammalian species. Our results may provide an alternative approach to enhance MHC stabilization capacity and immunogenicity of low-affinity peptides for induction of robust tumor-specific CTL. [Cancer Res 2009;69(19):7784–92]
Identification of a Novel Small Molecule HIF-1α Translation Inhibitor
Authors: Narita Takuhito , Yin Shaoman , Gelin Christine F. , Moreno Carlos S. , Yepes Manuel , Nicolaou K.C. , Van Meir Erwin G.
Published: September 2009

Purpose: Hypoxia inducible factor-1 (HIF-1), the central mediator of the cellular response to low oxygen, functions as a transcription factor for a broad range of genes that provide adaptive responses to oxygen deprivation. HIF-1 is overexpressed in cancer and has become an important therapeutic target in solid tumors. In this study, a novel HIF-1α inhibitor was identified and its molecular mechanism was investigated.

Experimental Design: Using a HIF-responsive reporter cell–based assay, a 10,000-member natural product–like chemical compound library was screened to identify novel HIF-1 inhibitors. This led us to discover KC7F2, a lead compound with a central structure of cystamine. The effects of KC7F2 on HIF-1 transcription, translation, and protein degradation processes were analyzed.

Results: KC7F2 markedly inhibited HIF-mediated transcription in cells derived from different tumor types, including glioma, breast, and prostate cancers, and exhibited enhanced cytotoxicity under hypoxia. KC7F2 prevented the activation of HIF-target genes such as carbonic anhydrase IX, matrix metalloproteinase 2 (MMP2), endothelin 1, and enolase 1. An investigation into the mechanism of action of KC7F2 showed that it worked through the down-regulation of HIF-1α protein synthesis, an effect accompanied by the suppression of the phosphorylation of eukaryotic translation initiation factor 4E binding protein 1 and p70 S6 kinase, key regulators of HIF-1α protein synthesis.

Conclusion: These results show that KC7F2 is a potent HIF-1 pathway inhibitor and its potential as a cancer therapy agent warrants further study. (Clin Cancer Res 2009;15(19):6128–36)
A Comparison of Phase II Study Strategies
Authors: Hunsberger Sally , Zhao Yingdong , Simon Richard
Published: September 2009

The traditional oncology drug development paradigm of single arm phase II studies followed by a randomized phase III study has limitations for modern oncology drug development. Interpretation of single arm phase II study results is difficult when a new drug is used in combination with other agents or when progression-free survival is used as the endpoint rather than tumor shrinkage. Randomized phase II studies are more informative for these objectives but increase both the number of patients and time required to determine the value of a new experimental agent. In this article, we compare different phase II study strategies to determine the most efficient drug development path in terms of number of patients and length of time to conclusion of drug efficacy on overall survival. (Clin Cancer Res 2009;15(19):5950–5)
Disrupting Polyamine Homeostasis as a Therapeutic Strategy for Neuroblastoma
Authors: Evageliou Nicholas F. , Hogarty Michael D.
Published: September 2009

MYC genes are deregulated in a plurality of human cancers. Through direct and indirect mechanisms, the MYC network regulates the expression of > 15% of the human genome, including both protein-coding and noncoding RNAs. This complexity has complicated efforts to define the principal pathways mediating MYC's oncogenic activity. MYC plays a central role in providing for the bioenergetic and biomass needs of proliferating cells, and polyamines are essential cell constituents supporting many of these functions. The rate-limiting enzyme in polyamine biosynthesis, ODC, is a bona fide MYC target, as are other regulatory enzymes in this pathway. A wealth of data link enhanced polyamine biosynthesis to cancer progression, and polyamine depletion may limit the malignant transformation of preneoplastic lesions. Studies with transgenic cancer models also support the finding that the effect of MYC on tumor initiation and progression can be attenuated through the repression of polyamine production. High-risk neuroblastomas (an often lethal embryonal tumor in which MYC activation is paramount) deregulate numerous polyamine enzymes to promote the expansion of intracellular polyamine pools. Selective inhibition of key enzymes in this pathway, e.g., using DFMO and/or SAM486, reduces tumorigenesis and synergizes with chemotherapy to regress tumors in preclinical models. Here, we review the potential clinical application of these and additional polyamine depletion agents to neuroblastoma and other advanced cancers in which MYC is operative. (Clin Cancer Res 2009;15(19):5956–61)
Phase I Dose-Escalation and Pharmacokinetic Study of Dasatinib in Patients with Advanced Solid Tumors
Authors: Demetri George D. , Lo Russo Patricia , MacPherson Iain R.J. , Wang Ding , Morgan Jeffrey A. , Brunton Valerie G. , Paliwal Prashni , Agrawal Shruti , Voi Maurizio , Evans T.R. Jeffry
Published: September 2009

Purpose: To determine the maximum tolerated dose, dose-limiting toxicity (DLT), and recommended phase II dose of dasatinib in metastatic solid tumors refractory to standard therapies or for which no effective standard therapy exists.

Experimental Design: In this phase I, open-label, dose-escalation study, patients received 35 to 160 mg of dasatinib twice daily in 28-day cycles either every 12 hours for 5 consecutive days followed by 2 nontreatment days every week (5D2) or as continuous, twice-daily (CDD) dosing.

Results: Sixty-seven patients were treated (5D2, n = 33; CDD, n = 34). The maximum tolerated doses were 120 mg twice daily 5D2 and 70 mg twice daily CDD. DLTs with 160 mg 5D2 were recurrent grade 2 rash, grade 3 lethargy, and one patient with both grade 3 prolonged bleeding time and grade 3 hypocalcemia; DLTs with 120 mg twice daily CDD were grade 3 nausea, grade 3 fatigue, and one patient with both grade 3 rash and grade 2 proteinuria. The most frequent treatment-related toxicities across all doses were nausea, fatigue, lethargy, anorexia, proteinuria, and diarrhea, with infrequent hematologic toxicities. Pharmacokinetic data indicated rapid absorption, dose proportionality, and lack of drug accumulation. Although no objective tumor responses were seen, durable stable disease was observed in 16% of patients.

Conclusion: Dasatinib was well tolerated in this population, with a safety profile similar to that observed previously in leukemia patients, although with much less hematologic toxicity. Limited, although encouraging, preliminary evidence of clinical activity was observed. Doses of 120 mg twice daily (5D2) or 70 mg twice daily (CDD) are recommended for further studies in patients with solid tumors. (Clin Cancer Res 2009;15(19):6232–40)
Vasoactivity of AG014699, a Clinically Active Small Molecule Inhibitor of Poly(ADP-ribose) Polymerase: a Contributory Factor to Chemopotentiation In vivo?
Authors: Ali Majid , Telfer Brian A. , McCrudden Cian , O'Rourke Martin , Thomas Huw D. , Kamjoo Marzieh , Kyle Suzanne , Robson Tracy , Shaw Chris , Hirst David G. , Curtin Nicola J. , Williams Kaye J.
Published: September 2009

Purpose: Poly(ADP-ribose) polymerase (PARP) plays an important role in DNA repair, and PARP inhibitors can enhance the activity of DNA-damaging agents in vitro and in vivo. AG014699 is a potent PARP inhibitor in phase II clinical development. However, the range of therapeutics with which AG014699 could interact via a DNA-repair based mechanism is limited. We aimed to investigate a novel, vascular-based activity of AG014699, underlying in vivo chemosensitization, which could widen its clinical application.

Experimental Design: Temozolomide response was analyzed in vitro and in vivo. Vessel dynamics were monitored using “mismatch” following the administration of perfusion markers and real-time analysis of fluorescently labeled albumin uptake in to tumors established in dorsal window chambers. Further mechanistic investigations used ex vivo assays of vascular smooth muscle relaxation, gut motility, and myosin light chain kinase (MLCK) inhibition.

Results: AG014699 failed to sensitize SW620 cells to temozolomide in vitro but induced pronounced enhancement in vivo. AG014699 (1 mg/kg) improved tumor perfusion comparably with the control agents nicotinamide (1 g/kg) and AG14361 (forerunner to AG014699; 10 mg/kg). AG014699 and AG14361 relaxed preconstricted vascular smooth muscle more potently than the standard agent, hydralazine, with no impact on gut motility. AG014699 inhibited MLCK at concentrations that relaxed isolated arteries, whereas AG14361 had no effect.

Conclusion: Increased vessel perfusion elicited by AG014699 could increase tumor drug accumulation and therapeutic response. Vasoactive concentrations of AG014699 do not cause detrimental side effects to gut motility and may increase the range of therapeutics with which AG014699 could be combined with for clinical benefit. (Clin Cancer Res 2009;15(19):6106–12)
A Phase I Dose-Finding Study of 5-Azacytidine in Combination with Sodium Phenylbutyrate in Patients with Refractory Solid Tumors
Authors: Lin Jianqing , Gilbert Jill , Rudek Michelle A. , Zwiebel James A. , Gore Steve , Jiemjit Anchalee , Zhao Ming , Baker Sharyn D. , Ambinder Richard F. , Herman James G. , Donehower Ross C. , Carducci Michael A.
Published: September 2009

Purpose: This was a phase I trial to determine the minimal effective dose and optimal dose schedule for 5-azacytidine (5-AC) in combination with sodium phenylbutyrate in patients with refractory solid tumors. The pharmacokinetics, pharmacodynamics, and antineoplastic effects were also studied.

Experimental Design: Three dosing regimens were studied in 27 patients with advanced solid tumors, and toxicity was recorded. The pharmacokinetics of the combination of drugs was evaluated. Repeat tumor biopsies and peripheral blood mononuclear cells (PBMC) were analyzed to evaluate epigenetic changes in response to therapy. EBV titers were evaluated as a surrogate measure for gene re-expression of epigenetic modulation in PBMC.

Results: The three dose regimens of 5-AC and phenylbutyrate were generally well tolerated and safe. A total of 48 cycles was administrated to 27 patients. The most common toxicities were bone marrow suppression–related neutropenia and anemia, which were minor. The clinical response rate was disappointing for the combination of agents. One patient showed stable disease for 5 months whereas 26 patients showed progressive disease as the best tumor response. The administration of phenylbutyrate and 5-AC did not seem to alter the pharmacokinetics of either drug. Although there were individual cases of targeted DNA methyltransferase activity and histone H3/4 acetylation changes from paired biopsy or PBMC, no conclusive statement can be made based on these limited correlative studies.

Conclusion: The combination of 5-AC and phenylbutyrate across three dose schedules was generally well tolerated and safe, yet lacked any real evidence for clinical benefit. (Clin Cancer Res 2009;15(19):6241–9)
A Novel Reduced Immunogenicity Bispecific Targeted Toxin Simultaneously Recognizing Human Epidermal Growth Factor and Interleukin-4 Receptors in a Mouse Model of Metastatic Breast Carcinoma
Authors: Oh Seunguk , Stish Brad J. , Sachdev Deepali , Chen Hua , Dudek Arkadiusz Z. , Vallera Daniel A.
Published: September 2009

Purpose: To develop a targeted biological drug that when systemically injected can penetrate to metastatic breast cancer tumors, one needs a drug of high potency and reduced immunogenicity. Thus, we bioengineered a novel bispecific ligand–directed toxin (BLT) targeted by dual high-affinity cytokines with a PE38KDEL COOH terminus. Our purpose was to reduce toxin immunogenicity using mutagenesis, measure the ability of mutated drug to elicit B-cell antitoxin antibody responses, and show that mutated drug was effective against systemic breast cancer in vivo.

Experimental Design: A new BLT was created in which both human epidermal growth factor (EGF) and interleukin 4 cytokines were cloned onto the same single-chain molecule with truncated Pseudomonas exotoxin (PE38). Site-specific mutagenesis was used to mutate amino acids in seven key epitopic toxin regions that dictate B-cell generation of neutralizing antitoxin antibodies. Bioassays were used to determine whether mutation reduced potency, and ELISA studies were done to determine whether antitoxin antibodies were reduced. Finally, a genetically altered luciferase xenograft model was used; this model could be imaged in real time to determine the effect on the systemic malignant human breast cancer MDA-MB-231.

Results: EGF4KDEL 7mut was significantly effective against established systemic human breast cancer and prevented metastatic spread. Mutagenesis reduced immunogenicity by ∼90% with no apparent loss in in vitro or in vivo activity.

Conclusions: Because EGF4KDEL 7mut was highly effective even when we waited 26 days to begin therapy and because immunogenicity was significantly reduced, we can now give multiple drug treatments for chemotherapy-refractory breast cancer in clinical trials. (Clin Cancer Res 2009;15(19):6137–47)
Gender Disparities in Metastatic Colorectal Cancer Survival
Authors: Hendifar Andrew , Yang Dongyun , Lenz Felicitas , Lurje Georg , Pohl Alexandra , Lenz Cosima , Ning Yan , Zhang Wu , Lenz Heinz-Josef
Published: September 2009

Purpose: Previous studies have shown that estrogen prevents colon cancer in postmenopausal women, indicating a role in colorectal cancer carcinogenesis and tumor progression. We investigated the interactions between sex, age, ethnicity, and year of diagnosis on overall survival (OS) in patients with metastatic colorectal cancer (MCRC).

Experimental Design: We screened 52,882 patients with MCRC from 1988 to 2004, using the Surveillance Epidemiology and End Results registry. Age at diagnosis, sex, ethnicity, tumor location, year of diagnosis, OS, and cancer-specific survival were evaluated using Cox proportional hazards model. The models were adjusted for marital status, tumor site, tumor differentiation, and treatment with radiation and/or surgery.

Results: We observed that younger women (18-44 years old) with MCRC lived longer than younger men (17 months versus 14; P < 0.0001, log-rank test). In contrast, older women (55 years and older) had significantly worse OS than older men (7 months versus 9; P < 0.0001, log-rank test). In multivariate analysis, we found that gender discrepancies have widened in recent years; young women diagnosed after 2000 have improved cancer-specific survival, compared to men (hazard ratio, 0.778; 95% confidence interval, 0.669-0.904), but those diagnosed before 2000 benefit less (hazard ratio, 0.931; 95% confidence interval, 0.821-1.056).

Conclusion: As one of the largest data sets analyzed to establish that younger women with MCRC survive longer than younger men, hormonal status not only seems to play an important role in the development and pathogenesis of colorectal cancer but also may be of prognostic significance. These data warrant further studies to determine the role of estrogen in colorectal cancer. (Clin Cancer Res 2009;15(20):6391–7)
Local Biosynthesis of Estrogen in Human Endometrial Carcinoma through Tumor-Stromal Cell Interactions
Authors: Takahashi-Shiga Naomi , Utsunomiya Hiroki , Miki Yasuhiro , Nagase Satoru , Kobayashi Rika , Matsumoto Mitsuyo , Niikura Hitoshi , Ito Kiyoshi , Yaegashi Nobuo
Published: September 2009

Purpose: The metabolism and synthesis of intratumoral estrogens are thought to play a very important role in the etiology and progression of endometrial carcinoma. Aromatase is a key enzyme in the conversion of androgens to estrogens, and aromatase localization studies have reported that aromatase immunoreactivity and mRNA were detected mainly in stromal cells. However, the effect of tumor-stromal interactions on local estrogen biosynthesis in endometrial carcinomas remains largely unknown.

Experimental Design: The endometrial carcinoma cell lines (Ishikawa and RL95-2) and breast carcinoma cell line (MCF-7) were cocultured with stromal cells isolated from endometrial carcinomas, and aromatization activity was measured using liquid chromatography-tandem mass spectrometry. We then confirmed the local biosynthesis of estrogens and tumor-stromal interactions on aromatase activity in Ishikawa and RL95-2 cells. In addition, we also examined the effects of aromatase inhibitors on cell proliferation.

Results: Aromatase activity was significantly higher in cocultures with Ishikawa or RL95-2 than in each monoculture, respectively. Estrone (E1) concentrations were significantly higher than estradiol (E2) concentrations in Ishikawa and RL95-2 cells, whereas E2 was significantly higher than E1 in MCF-7 cells. Cell proliferation was significantly inhibited in Ishikawa and RL95-2 cell cultures treated with aromatase inhibitors compared with control cultures.

Conclusions: These results indicate the contribution of not only E2 but also E1 to cancer cell proliferation in endometrial carcinoma. Our study may provide important information on metabolism and synthesis of intratumoral estrogens with regard to the etiology and progression of endometrial carcinoma, thus helping to achieve improved clinical responses in patients with endometrial carcinoma, who are treated with aromatase inhibitors. (Clin Cancer Res 2009;15(19):6028–34)
Loss of Heterozygosity at 2q37 in Sporadic Wilms' Tumor: Putative Role for miR-562
Authors: Drake Kylie M. , Ruteshouser E. Cristy , Natrajan Rachael , Harbor Phyllis , Wegert Jenny , Gessler Manfred , Pritchard-Jones Kathy , Grundy Paul , Dome Jeffrey , Huff Vicki , Jones Chris , Aldred Micheala A.
Published: September 2009

Purpose: Wilms' tumor is a childhood cancer of the kidney with an incidence of ∼1 in 10,000. Cooccurrence of Wilms' tumor with 2q37 deletion syndrome, an uncommon constitutional chromosome abnormality, has been reported previously in three children. Given these are independently rare clinical entities, we hypothesized that 2q37 harbors a tumor suppressor gene important in Wilms' tumor pathogenesis.

Experimental Design: To test this, we performed loss of heterozygosity analysis in a panel of 226 sporadic Wilms' tumor samples and mutation analysis of candidate genes.

Results: Loss of heterozygosity was present in at least 4% of cases. Two tumors harbored homozygous deletions at 2q37.1, supporting the presence of a tumor suppressor gene that follows a classic two-hit model. However, no other evidence of second mutations was found, suggesting that heterozygous deletion alone may be sufficient to promote tumorigenesis in concert with other genomic abnormalities. We show that miR-562, a microRNA within the candidate region, is expressed only in kidney and colon and regulates EYA1, a critical gene for renal development. miR-562 expression is reduced in Wilms' tumor and may contribute to tumorigenesis by deregulating EYA1. Two other candidate regions were localized at 2q37.3 and 2qter, but available data from patients with constitutional deletions suggest that these probably do not confer a high risk for Wilms' tumor.

Conclusions: Our data support the presence of a tumor suppressor gene at 2q37.1 and suggest that, in individuals with constitutional 2q37 deletions, any increased risk for developing Wilms' tumor likely correlates with deletions encompassing 2q37.1. (Clin Cancer Res 2009;15(19):5985–92)
Dendritic Cell Vaccination Combined with CTLA4 Blockade in Patients with Metastatic Melanoma
Authors: Ribas Antoni , Comin-Anduix Begoña , Chmielowski Bartosz , Jalil Jason , de la Rocha Pilar , McCannel Tara A. , Ochoa Maria Teresa , Seja Elizabeth , Villanueva Arturo , Oseguera Denise K. , Straatsma Bradley R. , Cochran Alistair J. , Glaspy John A. , Hui Liu , Marincola Francesco M. , Wang Ena , Economou James S. , Gomez-Navarro Jesus
Published: September 2009

Purpose: Tumor antigen–loaded dendritic cells (DC) are believed to activate antitumor immunity by stimulating T cells, and CTL-associated antigen 4 (CTLA4)–blocking antibodies should release a key negative regulatory pathway on T cells. The combination was tested in a phase I clinical trial in patients with advanced melanoma.

Experimental Design: Autologous DC were pulsed with MART-126-35 peptide and administered with a dose escalation of the CTLA4-blocking antibody tremelimumab. Sixteen patients were accrued to five dose levels. Primary end points were safety and immune effects; clinical efficacy was a secondary end point.

Results: Dose-limiting toxicities of grade 3 diarrhea and grade 2 hypophysitis developed in two of three patients receiving tremelimumab at 10 mg/kg monthly. Four patients had an objective tumor response, two partial responses and two complete responses, all melanoma free between 2 and 4 years after study initiation. There was no difference in immune monitoring results between patients with an objective tumor response and those without a response. Exploratory gene expression analysis suggested that immune-related gene signatures, in particular for B-cell function, may be important in predicting response.

Conclusion: The combination of MART-1 peptide–pulsed DC and tremelimumab results in objective and durable tumor responses at the higher range of the expected response rate with either agent alone. (Clin Cancer Res 2009;15(19):6267–76)
Antibody-Mediated Inhibition of Cathepsin S Blocks Colorectal Tumor Invasion and Angiogenesis
Authors: Burden Roberta E. , Gormley Julie A. , Jaquin Thomas J. , Small Donna M. , Quinn Derek J. , Hegarty Shauna M. , Ward Claire , Walker Brian , Johnston James A. , Olwill Shane A. , Scott Christopher J.
Published: September 2009

Purpose: Cathepsin S is a cysteine protease that promotes the invasion of tumor and endothelial cells during cancer progression. Here we investigated the potential to target cathepsin S using an antagonistic antibody, Fsn0503, to block these tumorigenic effects.

Experimental Design: A panel of monoclonal antibodies was raised to human cathepsin S. The effects of a selected antibody were subsequently determined using invasion and proteolysis assays. Endothelial cell tube formation and aorta sprouting assays were done to examine antiangiogenic effects. In vivo effects were also evaluated using HCT116 xenograft studies.

Results: A selected cathepsin S antibody, Fsn0503, significantly blocked invasion of a range of tumor cell lines, most significantly HCT116 colorectal carcinoma cells, through inhibition of extracellular cathepsin S–mediated proteolysis. We subsequently found enhanced expression of cathepsin S in colorectal adenocarcinoma biopsies when compared with normal colon tissue. Moreover, Fsn0503 blocked endothelial cell capillary tube formation and aortic microvascular sprouting. We further showed that administration of Fsn0503 resulted in inhibition of tumor growth and neovascularization of HCT116 xenograft tumors.

Conclusions: These results show that blocking the invasive and proangiogenic effects of cathepsin S with antibody inhibitors may have therapeutic utility upon further preclinical and clinical evaluation. (Clin Cancer Res 2009;15(19):6042–51)
Anticancer mechanisms of doxorubicin and zoledronic acid in breast cancer tumor growth in bone
Authors: Ottewell Penelope D. , Woodward Julia K. , Lefley Diane V. , Evans C. Alyson , Coleman Robert E. , Holen Ingunn
Published: September 2009

Patients with advanced breast cancer frequently develop bone metastases, and at this stage, the disease is considered incurable. Here, we show that a 6-week course of weekly administration of doxorubicin (2 mg/kg), followed 24 hours later by the bisphosphonate zoledronic acid (100μg/kg), causes substantial inhibition of MDA-MB-436 breast tumor burden in bone of immunocompromised mice, compared with administration of the single agents. Molecular analysis of tumors from animals treated sequentially with doxorubicin followed by zoledronic acid showed reduced numbers of proliferating tumor cells and decreased expression of cyclins E1, B, D1, and D3 as well as cdk2 and cdk4. Tumors from the sequential treatment group also displayed increased levels of apoptosis, increased expression of bcl2-associated X protein, decreased expression of B-cell chronic lymphocytic leukemia/lymphoma 2, and activation of caspase 3, 8, and 9. Zoledronic acid caused a small reduction in tumor volume, reduced tumor cell proliferation, and decreased expression of cyclins D1 and D3, compared with tumors from animals treated with saline or doxorubicin. Doxorubicin had no effect on tumor growth, cell cycle, or apoptosis in vivo, but did cause increased accumulation of a bisphosphonate in MDA-MB-436 cells in vitro, suggesting that doxorubicin may affect subsequent uptake of zoledronic acid. In support of this, accumulation of unprenylated Rap1A, a surrogate marker of zoledronic acid, was only detected in tumors following sequential treatment, and not following treatment with zoledronic acid alone. Our data are the first to show the specific molecular pathways by which sequential treatment with doxorubicin and zoledronic acid induce tumor cell apoptosis and inhibit proliferation in an in vivo model of breast tumor growth in bone. [Mol Cancer Ther 2009;8(10):2821–32]
Urinary Phytoestrogen Excretion and Postmenopausal Breast Cancer Risk: The Multiethnic Cohort Study
Authors: Goodman Marc T. , Shvetsov Yurii B. , Wilkens Lynne R. , Franke Adrian A. , Le Marchand Loic , Kakazu Kerry K. , Nomura Abraham M.Y. , Henderson Brian E. , Kolonel Laurence N.
Published: September 2009

The objective of this study was to examine the association of urinary phytoestrogens with the risk of postmenopausal breast cancer. Participants in the Multiethnic Cohort Study included 36,458 postmenopausal women who provided blood or urine specimens. A nested case-control study of breast cancer with biospecimens was created in which cases diagnosed after specimen collection were matched to two controls. Two hundred fifty-one women with breast cancer and 462 controls had urine available for analysis of urinary phytoestrogens. Odds ratios (OR) and 95% confidence intervals (CI) were obtained using conditional logistic regression. A nonmonotonic inverse trend (P = 0.04) in breast cancer risk was associated with increasing urinary excretion of genistein (OR 25th-75th percentile, 0.88; 95% CI, 0.78-0.99) and total isoflavones (OR 25th-75th percentile, 0.80; 95% CI, 0.65-0.99). A significant reduction in breast cancer risk in Japanese-American women was associated with the highest compared with the lowest quartile excretion of urinary daidzein (OR, 0.41; 95% CI, 0.19-0.89; Ptrend, 0.005). The risk of breast cancer was reduced among White women with the highest compared with the lowest quartile excretion of equol (OR, 0.27; 95% CI, 0.08-0.95), although the trend in risk was not significant (P = 0.07). Our results provide some support to the hypothesis that a diet rich in isoflavones from soy products reduces the risk of postmenopausal breast cancer, particularly in populations with comparatively high excretion of phytoestrogens.