bluuebunny/crossref_metadata_2025 huggingface dataset:
Negative Regulation of YAP by LATS1 Underscores Evolutionary Conservation of the Drosophila Hippo Pathway
Authors: Zhang Jianmin , Smolen Gromoslaw A. , Haber Daniel A.
Published: April 2008

The Hippo pathway defines a novel signaling cascade regulating cell proliferation and survival in Drosophila, which involves the negative regulation of the transcriptional coactivator Yorkie by the kinases Hippo and Warts. We have recently shown that the human ortholog of Yorkie, YAP, maps to a minimal amplification locus in mouse and human cancers, and that it mediates dramatic transforming activity in MCF10A primary mammary epithelial cells. Here, we show that LATS proteins (mammalian orthologs of Warts) interact directly with YAP in mammalian cells and that ectopic expression of LATS1, but not LATS2, effectively suppresses the YAP phenotypes. Furthermore, shRNA-mediated knockdown of LATS1 phenocopies YAP overexpression. Because this effect can be suppressed by simultaneous YAP knockdown, it suggests that YAP is the primary target of LATS1 in mammalian cells. Expression profiling of genes induced by ectopic expression of YAP or by knockdown of LATS1 reveals a subset of potential Hippo pathway targets implicated in epithelial-to-mesenchymal transition, suggesting that this is a key feature of YAP signaling in mammalian cells. [Cancer Res 2008;68(8):2789–94]
Tumor Escape Mechanism Governed by Myeloid-Derived Suppressor Cells
Authors: Nagaraj Srinivas , Gabrilovich Dmitry I.
Published: April 2008

T-cell nonresponsiveness is a critical factor in immune escape and myeloid-derived suppressor cells play a major role in organizing this phenomenon. Recent findings indicate that myeloid-derived suppressor cells can induce antigen-specific CD8+ T-cell tolerance through a posttranslation mechanism which involves modification (nitration) of CD8 and the T-cell receptor itself on the T-cell surface. Elucidation of this mechanism of T-cell tolerance offers new opportunities for therapeutic corrections of immune escape in cancer. [Cancer Res 2008;68(8):2561–63]
Soft Tissue Sarcoma Cells Are Highly Sensitive to AKT Blockade: A Role for p53-Independent Up-regulation of GADD45α
Authors: Zhu Quan-Sheng , Ren Wenhong , Korchin Borys , Lahat Guy , Dicker Adam , Lu Yiling , Mills Gordon , Pollock Raphael E. , Lev Dina
Published: April 2008

The AKT signaling pathway is activated in soft tissue sarcoma (STS). However, AKT blockade has not yet been studied as a potential targeted therapeutic approach. Here, we examined the in vitro and in vivo effects of AKT inhibition in STS cells. Western blot analysis was used to evaluate the expression of AKT pathway components and the effect of AKT stimulation and inhibition on their phosphorylation. Cell culture assays were used to assess the effect of AKT blockade (using a phosphatidylinositol 3-kinase inhibitor and a specific AKT inhibitor) on STS cell growth, cell cycle, and apoptosis. Oligoarrays were used to determine gene expression changes in response to AKT inhibition. Reverse transcription–PCR was used for array validation. Specific small inhibitory RNA was used to knockdown GADD45α. Human STS xenografts in nude mice were used for in vivo studies, and immunohistochemistry was used to assess the effect of treatment on GADD45α expression, proliferation, and apoptosis. Multiple STS cell lines expressed activated AKT. AKT inhibition decreased STS downstream target phosphorylation and growth in vitro; G2 cell cycle arrest and apoptosis were also observed. AKT inhibition induced GADD45α mRNA and protein expression in all STS cells treated independent of p53 mutational status. GADD45α knockdown attenuated the G2 arrest induced by AKT inhibition. In vivo, AKT inhibition led to decreased STS xenograft growth. AKT plays a critical role in survival and proliferation of STS cells. Modulation of AKT kinase activity may provide a novel molecularly based strategy for STS-targeted therapies. [Cancer Res 2008;68(8):2895–903]
Epigenetic Inactivation of the Canonical Wnt Antagonist SRY-Box Containing Gene 17 in Colorectal Cancer
Authors: Zhang Wei , Glöckner Sabine C. , Guo Mingzhou , Machida Emi Ota , Wang David H. , Easwaran Hariharan , Van Neste Leander , Herman James G. , Schuebel Kornel E. , Watkins D. Neil , Ahuja Nita , Baylin Stephen B.
Published: April 2008

SRY-box containing gene 17 (Sox17) is a member of the high mobility group (HMG) transcription factor superfamily, which plays critical roles in the regulation of development and stem/precursor cell function, at least partly through repression of Wnt pathway activity. Modulators controlling aberrant Wnt signaling activation are frequently disrupted in human cancers through complementary effects of epigenetic and genetic changes. Our recent global analysis of CpG island hypermethylation and gene expression in colorectal cancer (CRC) cell lines revealed that SOX17 gene silencing is associated with DNA hypermethylation of a CpG island in the promoter region. Here, we report that CpG island methylation-dependent silencing of SOX17 occurs in 100% of CRC cell lines, 86% of colorectal adenomas, 100% of stage I and II CRC, 89% of stage III CRC, 89% of primary esophageal cancer, and 50% of non–small cell lung cancer. Overexpression of SOX17 in HCT116 CRC cells inhibits colony growth and β-catenin/T-cell factor–dependent transcription. Structure-based deletion analysis further shows the presence of a Wnt signaling repression domain in the SOX17 HMG box. Together, our studies suggest that SOX17 is a negative modulator of canonical Wnt signaling, and that SOX17 silencing due to promoter hypermethylation is an early event during tumorigenesis and may contribute to aberrant activation of Wnt signaling in CRC. [Cancer Res 2008;68(8):2764–72]
Novel and Highly Recurrent Chromosomal Alterations in Sézary Syndrome
Authors: Vermeer Maarten H. , van Doorn Remco , Dijkman Remco , Mao Xin , Whittaker Sean , van Voorst Vader Pieter C. , Gerritsen Marie-Jeanne P. , Geerts Marie-Louise , Gellrich Sylke , Söderberg Ola , Leuchowius Karl-Johan , Landegren Ulf , Out-Luiting Jacoba J. , Knijnenburg Jeroen , IJszenga Marije , Szuhai Karoly , Willemze Rein , Tensen Cornelis P.
Published: April 2008

This study was designed to identify highly recurrent genetic alterations typical of Sézary syndrome (Sz), an aggressive cutaneous T-cell lymphoma/leukemia, possibly revealing pathogenetic mechanisms and novel therapeutic targets. High-resolution array-based comparative genomic hybridization was done on malignant T cells from 20 patients. Expression levels of selected biologically relevant genes residing within loci with frequent copy number alteration were measured using quantitative PCR. Combined binary ratio labeling-fluorescence in situ hybridization karyotyping was done on malignant cells from five patients. Minimal common regions with copy number alteration occurring in at least 35% of patients harbored 15 bona fide oncogenes and 3 tumor suppressor genes. Based on the function of the identified oncogenes and tumor suppressor genes, at least three molecular mechanisms are relevant in the pathogenesis of Sz. First, gain of cMYC and loss of cMYC antagonists (MXI1 and MNT) were observed in 75% and 40% to 55% of patients, respectively, which were frequently associated with deregulated gene expression. The presence of cMYC/MAX protein heterodimers in Sézary cells was confirmed using a proximity ligation assay. Second, a region containing TP53 and genome maintenance genes (RPA1/HIC1) was lost in the majority of patients. Third, the interleukin 2 (IL-2) pathway was affected by gain of STAT3/STAT5 and IL-2 (receptor) genes in 75% and 30%, respectively, and loss of TCF8 and DUSP5 in at least 45% of patients. In sum, the Sz genome is characterized by gross chromosomal instability with highly recurrent gains and losses. Prominent among deregulated genes are those encoding cMYC, cMYC-regulating proteins, mediators of MYC-induced apoptosis, and IL-2 signaling pathway components. [Cancer Res 2008;68(8):2689–98]
A Requirement for DICER to Maintain Full Promoter CpG Island Hypermethylation in Human Cancer Cells
Authors: Ting Angela H. , Suzuki Hiromu , Cope Leslie , Schuebel Kornel E. , Lee Byron H. , Toyota Minoru , Imai Kohzoh , Shinomura Yasuhisa , Tokino Takashi , Baylin Stephen B.
Published: April 2008

Promoter hypermethylation is a prevalent phenomenon, found in virtually all cancer types studied thus far, and accounts for tumor suppressor gene silencing in the absence of genetic mutations. The mechanism behind the establishment and maintenance of such aberrant hypermethylation has been under intense study. Here, we have uncovered a link between aberrant gene silencing associated with promoter CpG island DNA methylation and the siRNA/miRNA processing enzyme, DICER, in human cancer cells. By comparing demethylated HCT116 colon cancer cells with HCT116 cells genetically rendered hypomorphic for DICER, we identified a group of epigenetically silenced genes that became reactivated in the absence of functional DICER. This reactivation is associated with a dramatic loss of localized promoter DNA hypermethylation. Thus, intact DICER is required to maintain full promoter DNA hypermethylation of select epigenetically silenced loci in human cancer cells. [Cancer Res 2008;68(8):2570–5]
New Derivatives of Vitamin B12 Show Preferential Targeting of Tumors
Authors: Waibel Robert , Treichler Hansjörg , Schaefer Niklaus G. , van Staveren Dave R. , Mundwiler Stefan , Kunze Susanne , Küenzi Martin , Alberto Roger , Nüesch Jakob , Knuth Alexander , Moch Holger , Schibli Roger , Schubiger Pius August
Published: April 2008

Rapidly growing cells show an increased demand for nutrients and vitamins. The objective of our work is to exploit the supply route of vitamin B12 to deliver new derivatives of this vital vitamin to hyperproliferative cells. To date, radiolabeled (57Co and 111In) vitamin B12 derivatives showed labeling of tumor tissue but also undesired high accumulation of radioactivity in normal tissue. By abolishing the interaction of a tailored vitamin B12 derivative to its transport protein transcobalamin II and therefore interrupting transcobalamin II receptor and megalin mediated uptake in normal tissue, preferential accumulation of a radiolabeled vitamin in cancer tissue could be accomplished. We identified transcobalamin I on tumors as a possible new receptor for this preferential accumulation of vitamin-mediated targeting. The low systemic distribution of radioactivity and the high tumor to blood ratio opens the possibility of a more successful clinical application of vitamin B12 for imaging or therapy. [Cancer Res 2008;68(8):2904–11]
Disrupted Expression of CXCL5 in Colorectal Cancer Is Associated with Rapid Tumor Formation in Rats and Poor Prognosis in Patients
Authors: Speetjens Frank M. , Kuppen Peter J.K. , Sandel Maro H. , Menon Anand G. , Burg Danny , van de Velde Cornelis J.H. , Tollenaar Rob A.E.M. , de Bont Hans J.G.M. , Nagelkerke J. Fred
Published: April 2008

Purpose: We isolated a subline (CC531M) from the CC531S rat colon carcinoma cell line, which grows and metastasizes much more rapidly than CC531S. We found, using RNA expression profiling, that one of the major changes in the CC531M cell line was a 5.8-fold reduction of the chemokine CXCL5. The purpose of this study was to determine the effect of CXCL5 expression on colorectal tumor growth and metastasis.

Experimental Design: CC531 clones were generated with either knockdown or restored expression of CXCL5. These clones were inoculated in the liver of rats. In addition, in two independent cohorts of colorectal cancer patients, the level of CXCL5 expression was determined and associated to clinical variables.

Results: Knockdown of CXCL5 expression in CC531S resulted in rapid tumor growth and increased number of metastasis, whereas restored expression of CXCL5 in CC531M resulted in a return of the “mild” tumor growth pattern of the parental cell line CC531S. In vitro, no difference was found in proliferation rate between clones with either high or low expression of CXCL5, suggesting that environmental interactions directed by CXCL5 determine tumor outgrowth. Finally, the importance of our findings was established for patients with colorectal cancer. We found that low expression of CXCL5 was significantly associated with poor prognosis for colorectal cancer patients. CXCL5 showed a trend (P = 0.05) for a positive correlation with intratumoral CD8+ T-cell infiltration, suggesting a possible explanation for the observed poorer prognosis.

Conclusions: Our results show that CXCL5 is important in growth and development of colorectal cancer, implicating a future role in both cancer therapy and diagnosis.
Sunitinib for Treatment of Advanced Renal Cell Cancer: Primary Tumor Response
Authors: van der Veldt Astrid A.M. , Meijerink Martijn R. , van den Eertwegh Alfons J.M. , Bex Axel , de Gast Gijsbert , Haanen John B.A.G. , Boven Epie
Published: April 2008

Purpose: Nephrectomy before immunotherapy in patients with metastatic renal cell cancer (RCC) will improve patient outcome. In addition, the primary tumor is known to be refractory to cytokines. Sunitinib is now approved for treatment of advanced RCC, but its effect on the primary tumor has yet to be reported.

Experimental Design: All patients treated with sunitinib for advanced RCC without prior nephrectomy were reviewed and sequential computed tomography scans were evaluated for response in the primary tumor as well as metastases according to Response Evaluation Criteria in Solid Tumors. Volumes of primary tumors and central necrotic areas were measured with the perimeter method.

Results: Computed tomography scans were available for evaluation of response in 17 of 22 patients with a primary tumor in situ (1 patient with two primaries). According to Response Evaluation Criteria in Solid Tumors, 4 patients had a partial response, 12 had stable disease, and 1 had progressive disease. The one-dimensional longest diameter of the primary tumor correlated with the volumetric measurements both at baseline and at the time of evaluation of response. Excluding the patient with progressive disease, the median volume reduction was 31% associated with a median increase in the volume of necrosis of 39%. Three patients underwent nephrectomy and tumors showed extensive necrotic areas next to small fields of vital tumor cells.

Conclusions: Sunitinib can induce a significant reduction in volume of primary renal cell tumors. Further trials need to address the role of nephrectomy in advanced RCC patients on sunitinib treatment.
KIT Mutations Induce Intracellular Retention and Activation of an Immature Form of the KIT Protein in Gastrointestinal Stromal Tumors
Authors: Tabone-Eglinger Séverine , Subra Frédéric , El Sayadi Hiba , Alberti Laurent , Tabone Eric , Michot Jean-Philippe , Théou-Anton Nathalie , Lemoine Antoinette , Blay Jean-Yves , Emile Jean-François
Published: April 2008

Purpose: Gastrointestinal stromal tumors (GIST) are frequently associated with gain-of-function mutations of KIT, which can be inhibited by imatinib both in vitro and in vivo. The survival of patients with GIST, following imatinib therapy, has been correlated with the nature of mutations but not with KIT expression.

Experimental Design: Subcellular localization, activation, and trafficking of the mature and the immature forms of KIT were investigated in GIST samples and in NIH3T3 cells infected with two different GIST-type exon 11–mutated human KIT cDNA.

Results: Paranuclear dot expression of KIT was more frequent in GISTs with homozygous KIT mutations than in those with heterozygous (P = 0.01) or no mutations (P < 0.01). Activation of the immature 125 kDa form of KIT was detected in most GISTs with KIT mutations but not in GISTs without KIT mutations. In NIH3T3 cells, mutant KIT was mainly retained within endoplasmic reticulum and Golgi compartments in an immature constitutively phosphorylated form, whereas the wild-type KIT was expressed at the plasma membrane, in a mature nonphosphorylated form. Imatinib-induced inhibition of the phosphorylation of immature and mature mutant KIT proteins resulted in the restoration of KIT expression at the cell surface.

Conclusions: These results show that GIST-type KIT mutations induce an activation-dependent alteration of normal maturation and trafficking, resulting in the intracellular retention of the activated kinase within the cell. These observations likely account for the absence of correlation between response to imatinib and KIT expression using immunohistochemistry and may deserve to be investigated in other tyrosine kinase–activated tumors.
Loss of Complex I due to Mitochondrial DNA Mutations in Renal Oncocytoma
Authors: Mayr Johannes A. , Meierhofer David , Zimmermann Franz , Feichtinger Rene , Kögler Christian , Ratschek Manfred , Schmeller Nikolaus , Sperl Wolfgang , Kofler Barbara
Published: April 2008

Purpose: Many solid tumors exhibit abnormal aerobic metabolism characterized by increased glycolytic capacity and decreased cellular respiration. Recently, mutations in the nuclear encoded mitochondrial enzymes fumarate hydratase and succinate dehydrogenase have been identified in certain tumor types, thus demonstrating a direct link between mitochondrial energy metabolism and tumorigenesis. Although mutations in the mitochondrial genome (mitochondrial DNA, mtDNA) also can affect aerobic metabolism and mtDNA alterations are frequently observed in tumor cells, evidence linking respiratory chain deficiency in a specific tumor type to a specific mtDNA mutation has been lacking.

Experimental Design: To identify mitochondrial alterations in oncocytomas, we investigated the activities of respiratory chain enzymes and sequenced mtDNA in 15 renal oncocytoma tissues.

Results: Here, we show that loss of respiratory chain complex I (NADH/ubiquinone oxidoreductase) is associated with renal oncocytoma. Enzymatic activity of complex I was undetectable or greatly reduced in the tumor samples (n = 15). Blue Native gel electrophoresis of the multisubunit enzyme complex revealed a lack of assembled complex I. Mutation analysis of the mtDNA showed frame-shift mutations in the genes of either subunit ND1, ND4, or ND5 of complex I in 9 of the 15 tumors.

Conclusion: Our data indicate that isolated loss of complex I is a specific feature of renal oncocytoma and that this deficiency is frequently caused by somatic mtDNA mutations.
Inhibiting Fatty Acid Synthase for Chemoprevention of Chemically Induced Lung Tumors
Authors: Orita Hajime , Coulter Jonathan , Tully Ellen , Kuhajda Francis P. , Gabrielson Edward
Published: April 2008

Purpose: Fatty acid synthase (FAS) is overexpressed in lung cancer, and we have investigated the potential use of FAS inhibitors for chemoprevention of lung cancer.

Experimental Design: Expression of FAS was evaluated in preinvasive human lung lesions (bronchial squamous dysplasia and atypical adenomatous hyperplasia) and in murine models of lung tumorigenesis [4-(methylnitrosamino)-I-(3-pyridyl)-1-butanone–induced and urethane-induced lung tumors in A/J mice]. Then, the ability of pharmacologic inhibitors of FAS to prevent development of the murine tumors was investigated. Finally, the effect of the FAS inhibitor treatment of levels of phosphorylated Akt in the murine tumors was evaluated by immunohistochemistry.

Results: Immunohistochemical studies show that human bronchial dysplasia and atypical adenomatous hyperplasia express high levels of FAS compared with normal lung tissues, suggesting that FAS might be a target for intervention in lung carcinogenesis. FAS is also expressed at high levels in chemically induced murine lung tumors, and the numbers and sizes of those murine tumors are significantly reduced by treating carcinogen-exposed mice with pharmacologic inhibitors of FAS, C75 and C93. C93 treatment is associated with reduced levels of phosphorylated Akt in tumor tissues, suggesting that inhibition of this signal transduction pathway might be involved in the chemopreventative activity of this compound.

Conclusions: We conclude that increased levels of FAS are common in human preinvasive neoplasia of the lung. Based on studies in mouse models, it seems that inhibiting FAS is an effective strategy in preventing and retarding growth of lung tumors that have high expression of this enzyme.
Therapeutic Significance of Elevated Tissue Transglutaminase Expression in Pancreatic Cancer
Authors: Verma Amit , Guha Sushovan , Diagaradjane Parmeswaran , Kunnumakkara Ajaikumar B. , Sanguino Angela M. , Lopez-Berestein Gabriel , Sood Anil K. , Aggarwal Bharat B. , Krishnan Sunil , Gelovani Juri G. , Mehta Kapil
Published: April 2008

Purpose: Tissue transglutaminase (TG2) is a multifunctional protein that is implicated in development of drug resistance and metastasis. Therefore, we examined therapeutic targeting of TG2 for inhibiting growth and metastasis of in vivo growing pancreatic ductal adenocarcinoma (PDAC) in nude mice.

Experimental Design: We implanted Panc-28 pancreatic cancer cells to induce orthotopic PDAC tumors in nude mice and determined the efficacy of liposomal TG2 small interfering RNA (siRNA) either alone or in combination with gemcitabine.

Results: We show that down-regulation of endogenous TG2 by siRNA could effectively block the growth of PDAC. Moreover, down-regulation of TG2 significantly enhanced the therapeutic efficacy of gemcitabine against PDAC and inhibited metastatic spread of the disease. The antitumor activity was related to inhibition of proliferation, angiogenesis, and Akt phosphorylation.

Conclusion: siRNA-mediated down-regulation of TG2 represents a promising therapeutic approach for improved treatment of PDAC.
Ornithine Decarboxylase G316A Genotype Is Prognostic for Colorectal Adenoma Recurrence and Predicts Efficacy of Aspirin Chemoprevention
Authors: Hubner Richard A. , Muir Kenneth R. , Liu Jo-Fen , Logan Richard F.A. , Grainge Matthew J. , Houlston Richard S. ,   Members of the UKCAP Consortium
Published: April 2008

Purpose: The chemopreventive activity of aspirin in colorectal neoplasia may be explained in part by its effect on polyamine metabolism. The ornithine decarboxylase (ODC) G316A polymorphism affects polyamine metabolism through altered expression of ODC. We investigated the influence of ODC G316A on the chemopreventive activity of aspirin in colorectal adenoma (CRA) recurrence.

Experimental Design: We genotyped ODC G316A in 546 individuals in the United Kingdom Colorectal Adenoma Prevention trial of aspirin for CRA recurrence prevention and pooled our findings with data from two other randomized intervention trials.

Results: The United Kingdom Colorectal Adenoma Prevention participants with homozygous ODC 316AA genotype were at reduced CRA recurrence risk [relative risk (RR), 0.43; 95% confidence interval (95% CI), 0.16-1.15], particularly if also exposed to aspirin (RR, 0.24; 95% CI, 0.03-1.71). In the pooled analysis of 2,207 individuals, those with homozygous ODC 316AA genotype were at significantly reduced CRA recurrence risk (RR, 0.68; 95% CI, 0.47-0.99). Following stratification by genotype and aspirin exposure, individuals with homozygous wild-type or heterozygous genotypes derived modest benefit from aspirin (RR, 0.85; 95% CI, 0.72-1.01), whereas in those with both ODC 316AA genotype and aspirin exposure recurrence risk was halved (RR, 0.52; 95% CI, 0.29-0.91).

Conclusion: The ODC G316A genotype is prognostic for CRA recurrence and predictive of an enhanced response to aspirin in preventing recurrence. This variant has the potential to be a clinically useful genetic marker to identify individuals likely to derive the greatest benefit from aspirin chemoprevention.
Clinical Significance of High Mobility Group A2 in Human Gastric Cancer and Its Relationship to let-7 MicroRNA Family
Authors: Motoyama Kazuo , Inoue Hiroshi , Nakamura Yoshito , Uetake Hiroyuki , Sugihara Kenichi , Mori Masaki
Published: April 2008

Purpose: The high mobility group A2 (HMGA2) nonhistone chromosomal protein can modulate transcription by altering chromatin architecture. HMGA2 is highly expressed during embryogenesis and in various benign and malignant tumors. Recent studies report that HMGA2 is negatively regulated by the let-7 microRNA (miRNA) family. However, no studies have examined the clinical significance of HMGA2 and its relationship to the let-7 miRNA family in gastric cancer.

Experimental Design: Using quantitative real-time reverse transcription–PCR, we analyzed HMGA2 expression with respect to various clinicopathologic factors in 110 patients with gastric cancer. We also did an association study comparing HMGA2 expression and let-7 miRNA family expression in gastric cancer.

Results: Expression of HMGA2 in cancerous tissues was significantly higher than in noncancerous tissues (P < 0.05). Elevated HMGA2 expression was significantly correlated with serosal invasion (P < 0.05) and poor clinical prognosis (P < 0.05). A multivariate analysis showed that HMGA2 expression status was an independent prognostic factor (P < 0.05). An inverse correlation between HMGA2 and let-7a was found in gastric cancer cell lines (P = 0.08). The expressions of let-7a, let-7b, and let-7c in gastric cancer patients with low HMGA2 expression were significantly higher than those with high HMGA2 expression (P < 0.05).

Conclusions: High expression of HMGA2 in gastric cancer correlates with tumor invasiveness and is an independent prognostic factor. Furthermore, our findings suggest that HMGA2 is negatively regulated by the let-7 miRNA family in human gastric cancer.
Cyclooxygenase-2 dependent and independent antitumor effects induced by celecoxib in urinary bladder cancer cells
Authors: Dhawan Deepika , Jeffreys Antonella Borgatti , Zheng Rong , Stewart Jane C. , Knapp Deborah W.
Published: April 2008

Transitional cell carcinoma of the urinary bladder is the second most common genitourinary malignancy in people in the United States. Cyclooxygenase-2 (COX-2) is overexpressed in bladder cancer. COX-2 inhibitors have had antitumor activity against bladder cancer, but the mechanisms of action are unclear. Clinically relevant concentrations of COX-2 inhibitors fail to inhibit proliferation in standard in vitro assays. In pilot experiments, different culture conditions [standard monolayer, modified monolayer, soft agar, collagen, and poly(2-hydroxyethyl methacrylate)–coated plates] were assessed to determine conditions suitable for the study of COX inhibitor growth-inhibitory effects. This was followed by studies of the effects of clinically relevant concentrations of a selective COX-2 inhibitor (celecoxib) on urinary bladder cancer cell lines (HT1376, TCCSUP, and UMUC3). Celecoxib (≤5 μmol/L) inhibited proliferation of COX-2–expressing HT1376 cells in soft agar and modified monolayer cell culture conditions in a COX-2–dependent manner. COX-2 expression, however, did not always correlate with response to celecoxib. TCCSUP cells that express COX-2 were minimally affected by celecoxib, and UMUC3 cells that lack COX-2 expression were modestly inhibited by the drug. When UMUC3Cox-2/Tet cells overexpressing COX-2 under the control of tetracycline-inducible promoter were treated with celecoxib in modified monolayer cell culture, growth inhibition was found to be associated with changes in the expression of pRb. Not surprisingly, the proliferation of all cell lines was inhibited by excessively high concentrations of celecoxib. In conclusion, the modified culture conditions allowed detection of COX-2–dependent and COX-2–independent growth-inhibitory activity of celecoxib in urinary bladder cancer cells. [Mol Cancer Ther 2008;7(4):897–904]
A selective small molecule inhibitor of c-Met, PHA-665752, reverses lung premalignancy induced by mutant K-ras
Authors: Yang Yanan , Wislez Marie , Fujimoto Nobukazu , Prudkin Ludmila , Izzo Julie G. , Uno Futoshi , Ji Lin , Hanna Amy E. , Langley Robert R. , Liu Diane , Johnson Faye M. , Wistuba Ignacio , Kurie Jonathan M.
Published: April 2008

The c-Met receptor tyrosine kinase has been implicated in cellular transformation induced by mutant Ras, a commonly activated proto-oncogene in non-small cell lung cancer (NSCLC). However, the role of c-Met has not been defined in K-ras-mutant NSCLC, a disease for which no effective targeted therapeutic options currently exist. To acquire a greater understanding of its role, we used genetic and pharmacologic approaches to inhibit c-Met in mice and cultured cells. In KrasLA1 mice, which develop premalignant lung lesions that progress to multifocal lung adenocarcinomas owing to somatic mutations in K-ras, c-Met was expressed in multiple cell types within premalignant lung lesions, and high concentrations of HGF were detected in bronchoalveolar lavage samples. Short-term treatment with PHA-665752, a c-Met inhibitor, decreased the numbers of premalignant lung lesions and induced apoptosis in tumor cells and vascular endothelial cells within lesions. In cell culture, PHA-665752 induced apoptosis of a lung adenocarcinoma cell line derived from KrasLA1 mice (LKR-13) and a murine lung endothelial cell line (MEC). c-Met depletion by siRNA transfection induced apoptosis of MECs but not LKR-13 cells. Collectively, these findings suggest that apoptosis was an on-target effect of PHA-665752 in MECs but not in LKR-13 cells. We conclude that PHA-665752 inhibited lung tumorigenesis in KrasLA1 mice and may provide a novel therapeutic approach to the prevention of K-ras-mutant NSCLC. [Mol Cancer Ther 2008;7(4):952–60]
The T790M “gatekeeper” mutation in EGFR mediates resistance to low concentrations of an irreversible EGFR inhibitor
Authors: Godin-Heymann Nadia , Ulkus Lindsey , Brannigan Brian W. , McDermott Ultan , Lamb Jennifer , Maheswaran Shyamala , Settleman Jeffrey , Haber Daniel A.
Published: April 2008

Patients with non–small cell lung cancer (NSCLC) harboring activating mutations in the epidermal growth factor receptor (EGFR) kinase domain tend to respond well to the tyrosine kinase inhibitors, gefitinib and erlotinib. However, following clinical response, these patients typically relapse within a year of treatment. In many cases, resistance is caused by an acquired secondary EGFR kinase domain mutation, T790M. In vitro studies have shown that a new class of EGFR-irreversible inhibitors could overcome the resistance conferred by T790M. Clinical trials are under way to examine the efficacy of one of these inhibitors, HKI-272, in patients with NSCLC who initially responded to gefitinib/erlotinib and subsequently relapsed. To anticipate the possibility that patients who respond to irreversible inhibitors will develop secondary resistance to such inhibitors, as has been seen in other similar settings, we modeled acquired resistance to the dual EGFR/HER2-irreversible tyrosine kinase inhibitor HKI-272 in a NSCLC cell culture model. We found that HKI-272–resistant clones fall into two biochemical groups based on the retention of EGFR phosphorylation in the presence of the drug. Cells that retain phosphorylated EGFR have acquired the secondary mutation T790M. Moreover, HKI-272 can overcome T790M resistance only at suprapharmacologic concentrations. We further model mutations at EGFR C797 as a mechanism of resistance to irreversible EGFR inhibitors and show that although these mutants are resistant to the irreversible inhibitor, they retain erlotinib sensitivity. Our findings suggest that HKI-272 treatment at maximally tolerated dosing may lead to the emergence of T790M-mediated resistance, whereas treatment with a more potent irreversible inhibitor could yield a resistance mutation at EGFR C797. [Mol Cancer Ther 2008;7(4):874–9]
Aberrant Crypt Foci in the Adenoma Prevention with Celecoxib Trial
Authors: Cho Nancy L. , Redston Mark , Zauber Ann G. , Carothers Adelaide M. , Hornick Jason , Wilton Andrew , Sontag Stephen , Nishioka Norman , Giardiello Francis M. , Saltzman John R. , Gostout Chris , Eagle Craig J. , Hawk Ernest T. , Bertagnolli Monica M.
Published: April 2008

Aberrant crypt foci (ACF) are the earliest visible neoplastic lesions in the colorectum. The natural history of these lesions and their role in the adenoma-carcinoma sequence are unknown. We studied ACF in a subset of patients randomized to placebo (n = 17), celecoxib (200 mg twice daily; n = 15), or celecoxib (400 mg twice daily; n = 13) in the Adenoma Prevention with Celecoxib (APC) trial. Magnification chromoendoscopy was done to identify, count, and biopsy ACF within the rectum at baseline and after 8 to 12 months of treatment. A total of 655 ACF were identified in 45 patients. We examined 70 of these ACF histologically, and all 70 were nondysplastic. Cohort characteristics and APC trial treatment results for substudy patients were similar to those of the overall APC trial. There was no significant modulation of ACF by celecoxib (versus placebo; P = 0.77). Immunohistochemical comparison of ACF with adjacent normal mucosa showed that ACF had an increased proliferative index as determined by Ki-67 (P < 0.0001), but lacked other features of neoplasia such as increased cyclooxygenase-2 expression and microvessel density, nuclear localization of β-catenin, or decreased expression of the tumor suppressors SMAD4, Estrogen Receptor α, or MGMT. Only baseline SMAD4 expression in ACF correlated with posttreatment adenoma recurrence (independent of treatment arm; P = 0.01). The presence or number of nondysplastic ACF did not correlate with a higher risk of synchronous advanced or recurrent adenomas. Our overall results indicated that nondysplastic ACF were not accurate surrogate endpoint biomarkers of recurrent colorectal adenomas in the APC trial.
Difluoromethylornithine Plus Sulindac for the Prevention of Sporadic Colorectal Adenomas: A Randomized Placebo-Controlled, Double-Blind Trial
Authors: Meyskens Frank L. , McLaren Christine E. , Pelot Daniel , Fujikawa-Brooks Sharon , Carpenter Philip M. , Hawk Ernest , Kelloff Gary , Lawson Michael J. , Kidao Jayashri , McCracken John , Albers C. Gregory , Ahnen Dennis J. , Turgeon D. Kim , Goldschmid Steven , Lance Peter , Hagedorn Curt H. , Gillen Daniel L. , Gerner Eugene W.
Published: April 2008

Preclinical studies of chemoprevention drugs given in combination at low doses show remarkable efficacy in preventing adenomas with little additional toxicities, suggesting a strategy to improve risk to benefit ratios for preventing recurrent adenomas. Three hundred seventy-five patients with history of resected (≥3 mm) adenomas were randomly assigned to receive oral difluoromethylornithine (DFMO) 500 mg and sulindac 150 mg once daily or matched placebos for 36 months, stratified by use of low-dose aspirin (81 mg) at baseline and clinical site. Follow-up colonoscopy was done 3 years after randomization or off-study. Colorectal adenoma recurrence was compared among the groups with log-binomial regression. Comparing the outcome in patients receiving placebos to those receiving active intervention, (a) the recurrence of one or more adenomas was 41.1% and 12.3% (risk ratio, 0.30; 95% confidence interval, 0.18-0.49; P < 0.001); (b) 8.5% had one or more advanced adenomas, compared with 0.7% of patients (risk ratio, 0.085; 95% confidence interval, 0.011-0.65; P < 0.001); and (c) 17 (13.2%) patients had multiple adenomas (>1) at the final colonoscopy, compared with 1 (0.7%; risk ratio, 0.055; 0.0074-0.41; P < 0.001). Serious adverse events (grade ≥3) occurred in 8.2% of patients in the placebo group, compared with 11% in the active intervention group (P = 0.35). There was no significant difference in the proportion of patients reporting hearing changes from baseline. Recurrent adenomatous polyps can be markedly reduced by a combination of low oral doses of DFMO and sulindac and with few side effects.
Essential Features of Designating Out-of-Hospital Cardiac Arrest as a Reportable Event
Authors: Nichol Graham , Rumsfeld John , Eigel Brian , Abella Benjamin S. , Labarthe Darwin , Hong Yuling , O’Connor Robert E. , Mosesso Vincent N. , Berg Robert A. , Leeper Barbara “Bobbi” , Weisfeldt Myron L.
Published: April 2008

The 2010 impact goal of the American Heart Association is to reduce death rates from heart disease and stroke by 25% and to lower the prevalence of the leading risk factors by the same proportion. Much of the burden of acute heart disease is initially experienced out of hospital and can be reduced by timely delivery of effective prehospital emergency care. Many patients with an acute myocardial infarction die from cardiac arrest before they reach the hospital. A small proportion of those with cardiac arrest who reach the hospital survive to discharge. Current health surveillance systems cannot determine the burden of acute cardiovascular illness in the prehospital setting nor make progress toward reducing that burden without improved surveillance mechanisms. Accordingly, the goals of this article provide a brief overview of strategies for managing out-of-hospital cardiac arrest. We review existing surveillance systems for monitoring progress in reducing the burden of out-of-hospital cardiac arrest in the United States and make recommendations for filling significant gaps in these systems, including the following: 1. Out-of-hospital cardiac arrests and their outcomes through hospital discharge should be classified as reportable events as part of a heart disease and stroke surveillance system. 2. Data collected on patients’ encounters with emergency medical services systems should include descriptions of the performance of cardiopulmonary resuscitation by bystanders and defibrillation by lay responders. 3. National annual reports on key indicators of progress in managing acute cardiovascular events in the out-of-hospital setting should be developed and made publicly available. Potential barriers to action on cardiac arrest include concerns about privacy, methodological challenges, and costs associated with designating cardiac arrest as a reportable event.
Long-Term Mortality After Percutaneous Coronary Intervention With Drug-Eluting Stent Implantation Versus Coronary Artery Bypass Surgery for the Treatment of Multivessel Coronary Artery Disease
Authors: Park Duk-Woo , Yun Sung-Cheol , Lee Seung-Whan , Kim Young-Hak , Lee Cheol Whan , Hong Myeong-Ki , Kim Jae-Joong , Choo Suk Jung , Song Hyun , Chung Cheol Hyun , Lee Jae-Won , Park Seong-Wook , Park Seung-Jung
Published: April 2008

Background—

Although previous studies have compared the treatment effects of percutaneous coronary intervention and coronary artery bypass grafting (CABG), the long-term outcomes beyond 1 year among patients with multivessel coronary artery disease who underwent percutaneous coronary intervention with drug-eluting stents (DES) or CABG have not been evaluated.

Methods and Results—

Between January 2003 and December 2005, 3042 patients with multivessel disease underwent coronary implantation of DES (n=1547) or CABG (n=1495). The primary end point was all-cause mortality. In a crude analysis, the rate of long-term mortality was significantly higher in patients who underwent CABG than in those who underwent DES implantation (3-year unadjusted mortality rate, 7.0% for CABG versus 4.4% for percutaneous coronary intervention;
P
=0.01). However, after adjustment for baseline differences, the overall risks of death were similar among all patients (hazard ratio, 0.85; 95% confidence interval [CI], 0.56 to 1.30;
P
=0.45), diabetic patients (hazard ratio, 1.76; 95% CI, 0.82 to 3.78;
P
=0.15), and patients with compromised ventricular function (hazard ratio, 1.39; 95% CI, 0.41 to 4.65;
P
=0.60). In the anatomic subgroups, mortality benefit with DES implantation was noted in patients with 2-vessel disease with involvement of the nonproximal left anterior descending artery (hazard ratio, 0.23; 95% CI, 0.01 to 0.78;
P
=0.016). The rate of revascularization was significantly higher in the DES than in the CABG group (hazard ratio, 2.81; 95% CI, 2.11 to 3.75;
P
<0.001).

Conclusions—

For the treatment of multivessel coronary artery disease, percutaneous coronary intervention with DES implantation showed equivalent long-term mortality as CABG.
C-Reactive Protein Is Elevated 30 Years After Eclamptic Pregnancy
Authors: Hubel Carl A. , Powers Robert W. , Snaedal Sunna , Gammill Hilary S. , Ness Roberta B. , Roberts James M. , Arngrímsson Reynir
Published: April 2008

Women with a history of preeclampsia or eclampsia (seizure during preeclamptic pregnancy) are at increased risk for cardiovascular disease after pregnancy for reasons that remain unclear. Prospective studies during pregnancy suggest that inflammation, dyslipidemia, and insulin resistance are associated with increased risk of preeclampsia. Elevated serum C-reactive protein (CRP >3 mg/L) is an indicator of inflammation and cardiovascular risk. We hypothesized that Icelandic postmenopausal women with a history of eclampsia would manifest higher concentrations of serum CRP than Icelandic postmenopausal controls with a history of uncomplicated pregnancies. We also asked whether elevated CRP is associated with the dyslipidemia and insulin resistance previously identified in this cohort. CRP, measured by high-sensitivity enzyme-linked immunoassay, was higher in women with prior eclampsia (n=25) than controls (n=28) (median mg/L [interquartile range]: 9.0 [0.9 to 13.2] versus 2.0 [0.3 to 5.1];
P
<0.03). This difference remained significant after adjustment for body mass index, smoking, hormone replacement, and current age. Women with prior eclampsia clustered into either high CRP (range 8.97 to 40.6 mg/L, n=13) or lower CRP (median 1.0, range 0.05 to 3.77, n=12) subsets. The prior eclampsia/high CRP subset displayed significantly elevated systolic blood pressures, lower high-density lipoprotein (HDL) cholesterol, higher apolipoprotein B, and higher fasting insulin and homeostasis model of insulin resistance (HOMA) values compared to controls, whereas the prior eclampsia/low CRP subset differed from controls only by marginally increased apolipoprotein B. The triad of inflammation, low HDL, and insulin resistance may elevate risk for both preeclampsia/eclampsia and cardiovascular disease in later life.
Angioedema Incidence in US Veterans Initiating Angiotensin-Converting Enzyme Inhibitors
Authors: Miller Donald R. , Oliveria Susan A. , Berlowitz Dan R. , Fincke Benjamin G. , Stang Paul , Lillienfeld David E.
Published: April 2008

Angioedema is a rare but potentially serious complication of angiotensin-converting enzyme inhibitor (ACE) use. We conducted a study to estimate incidence of ACE-related angioedema and explore its determinants in a large racially diverse patient population. We used linked medical and pharmacy records to identify all patients in the US Veterans Affairs Health Care System from April 1999 through December 2000 who received first prescriptions for antihypertensive medications. We studied 195 192 ACE initiators and 399 889 patients initiating other antihypertensive medications (OAH). New angioedema was identified by diagnosis codes using methods validated in a national sample of 869 angioedema cases with confirmation for over 95% of cases. Overall, 0.20% of ACE initiators developed angioedema while on the medication and the incidence rate was 1.97 (1.77 to 2.18) cases per 1000 person years. This compares with a rate of 0.51 (0.43 to 0.59) in OAH initiators and the adjusted relative risk estimate was 3.56 (2.82 to 4.44). Fifty five percent of cases occurred within 90 days of first ACE use but risk remained elevated with prolonged use, even beyond 1 year. We estimate that 58.3% of angioedema in patients starting antihypertensives was related to ACE. We also found that angioedema rates were nearly 4-fold higher in blacks, 50% higher in women, and 12% lower in those with diabetes. This study provides a reliable estimate of angioedema incidence associated with ACE use in a diverse nontrial patient population, confirming that the incidence is low, but finding substantial variation by race, sex, and diabetes status.
Advanced Rain/No-Rain Classification Methods for Microwave Radiometer Observations over Land
Authors: Seto Shinta , Kubota Takuji , Takahashi Nobuhiro , Iguchi Toshio , Oki Taikan
Published: April 2008

Seto et al. developed rain/no-rain classification (RNC) methods over land for the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI). In this study, the methods are modified for application to other microwave radiometers. The previous methods match TMI observations with TRMM precipitation radar (PR) observations, classify the TMI pixels into rain pixels and no-rain pixels, and then statistically summarize the observed brightness temperature at the no-rain pixels into a land surface brightness temperature database. In the modified methods, the probability distribution of brightness temperature under no-rain conditions is derived from unclassified TMI pixels without the use of PR. A test with the TMI shows that the modified (PR independent) methods are better than the RNC method developed for the Goddard profiling algorithm (GPROF; the standard algorithm for the TMI) while they are slightly poorer than corresponding previous (PR dependent) methods. M2d, one of the PR-independent methods, is applied to observations from the Advanced Microwave Scanning Radiometer for Earth Observing Satellite (AMSR-E), is evaluated for a matchup case with PR, and is evaluated for 1 yr with a rain gauge dataset in Japan. M2d is incorporated into a retrieval algorithm developed by the Global Satellite Mapping of Precipitation project to be applied for the AMSR-E. In latitudes above 30°N, the rain-rate retrieval is compared with a rain gauge dataset by the Global Precipitation Climatology Center. Without a snow mask, a large amount of false rainfall due to snow contamination occurs. Therefore, a simple snow mask using the 23.8-GHz channel is applied and the threshold of the mask is optimized. Between 30° and 60°N, the optimized snow mask forces the miss of an estimated 10% of the total rainfall.
Settling of Particles beneath Water Waves
Authors: Eames Ian
Published: April 2008

Considered here is the motion of small particles beneath irrotational water waves. The added mass and inertial forces are shown to be an important role in the mean transport of particles. To leading order, particles are transported with a mean horizontal Stokes drift velocity and sediment with their terminal fall velocity. The combination of a settling velocity and a mean drift transports particles a finite distance forward from their point of release.
Testing Incapacitation Theory
Authors: Stahlkopf Christina , Males Mike , Macallair Daniel
Published: April 2008

Under incapacitation theory, higher incarceration rates are expected to correlate with accelerated reductions in crime. California’s contemporary incarceration patterns offer an opportunity to analyze the validity of this theory, particularly as it applies to young people. This study focuses on California’s juvenile incarceration and crime trends during the past half century. The findings of this study fail to demonstrate reduced crime rates through higher levels of juvenile incarceration, calling deterrence and incapacitation theories into serious question as effective youth crime reduction strategies and demonstrating the urgent need for California policy makers and legislators to consider alternative theories in response to crime and sentencing.