bluuebunny/crossref_metadata_2025 huggingface dataset:
Cyclooxygenase-2 Is Expressed in Neuroblastoma, and Nonsteroidal Anti-Inflammatory Drugs Induce Apoptosis and Inhibit Tumor Growth
In vivo
Authors: Johnsen John I. , Lindskog Magnus , Ponthan Frida , Pettersen Ingvild , Elfman Lotta , Orrego Abiel , Sveinbjörnsson Baldur , Kogner Per
Published: September 2005

Neuroblastoma is the single most common and deadly tumor of childhood and is often associated with therapy resistance. Cyclooxygenases (COXs) catalyze the conversion of arachidonic acid to prostaglandins. COX-2 is up-regulated in several adult epithelial cancers and is linked to proliferation and resistance to apoptosis. We detected COX-2 expression in neuroblastoma primary tumors and cell lines but not in normal adrenal medullas from children. Treatment of neuroblastoma cells with nonsteroidal anti-inflammatory drugs, inhibitors of COX, induced caspase-dependent apoptosis via the intrinsic mitochondrial pathway. Treatment of established neuroblastoma xenografts in nude rats with the dual COX-1/COX-2 inhibitor diclofenac or the COX-2–specific inhibitor celecoxib significantly inhibited tumor growth in vivo (P < 0.001). In vitro, arachidonic acid and diclofenac synergistically induced neuroblastoma cell death. This effect was further pronounced when lipooxygenases were simultaneously inhibited. Proton magnetic resonance spectroscopy (1H MRS) of neuroblastoma cells treated with COX inhibitors demonstrated accumulation of polyunsaturated fatty acids and depletion of choline compounds. Thus, 1H MRS, which can be performed with clinical magnetic resonance scanners, is likely to provide pharmacodynamic markers of neuroblastoma response to COX inhibition. Taken together, these data suggest the use of nonsteroidal anti-inflammatory drugs as a novel adjuvant therapy for children with neuroblastoma.
p73
G4C14-to-A4T14 Polymorphism and Risk of Lung Cancer
Authors: Li Guojun , Wang Li-E , Chamberlain Robert M. , Amos Christopher I. , Spitz Margaret R. , Wei Qingyi
Published: September 2005

Genetic variants in genes controlling cellular processes such as cell cycle, DNA repair, and apoptosis may modulate lung cancer risk. p73 has some p53-like activity and plays an important role in modulating these processes. The noncoding region of exon 2 of the p73 gene has two polymorphisms that are in complete linkage disequilibrium with one another, which may alter translation efficiency of the p73 protein. To test the hypothesis that this p73 polymorphism plays a role in the etiology of lung cancer, we conducted a hospital-based case-control study of 1054 patients newly diagnosed with lung cancer and 1139 cancer-free controls and evaluated the association between the p73 variant AT allele and risk of lung cancer. Cancer-free controls were frequency matched to the cases by age (±5 years), sex, and smoking status, and all subjects were non-Hispanic whites. The variant AT allele and genotypes were more common among the cases than among the controls (P = 0.0007 and P < 0.001, respectively). Compared with the GC/GC genotype, the variant GC/AT and AT/AT genotypes were associated with a statistically significantly increased risk for lung cancer [adjusted odds ratio (OR) = 1.32, 95% confidence interval (CI), 1.10–1.59 and OR = 1.54, 95% CI, 1.05–2.26, respectively] in an allele dose-effect relationship (trend test: P < 0.001). The risk associated with the AT allele (GC/AT+AT/AT) was more pronounced in younger (≤50 years) individuals (OR = 1.53, 95% CI, 1.00–2.37), men (OR = 1.61, 95% CI, 1.26–2.06), light smokers (OR = 1.58, 95% CI, 1.17–2.14), and squamous cell lung carcinoma (OR = 1.79, 95% CI, 1.32–2.42). These results suggest that this p73 polymorphism may be a marker for susceptibility to lung cancer.
Adhesion-Independent α6β4 Integrin Clustering Is Mediated by Phosphatidylinositol 3-Kinase
Authors: Gilcrease Michael Z. , Zhou Xiao , Welch Kristin
Published: September 2005

Clustering of cell-surface integrins is known to augment integrin-mediated signal transduction, but mechanisms of integrin clustering are poorly understood. Here we report that adhesion-independent clustering of α6β4 integrin, known to be important in mediating tumor cell motility, is driven by phosphatidylinositol 3-kinase (PI3K) but does not require activation of the PI3K-Akt pathway. We observed clustering of α6β4 in breast carcinoma cells after adhesion-independent cross-linking of the β4 integrin subunit. Clustering was significantly blocked when cross-linking was performed in the presence of PI3K inhibitors LY294002 and wortmannin. In contrast, no significant inhibition of clustering was observed with protein kinase C inhibitor GF109203X, rapamycin, or heparin. Although α6β4 clustering was blocked by PI3K inhibitors, clustering was not associated with increased PI3K lipid kinase activity or increased phosphorylation of Akt. A novel role for PI3K in α6β4 integrin clustering is proposed.
PEGylation Confers Greatly Extended Half-Life and Attenuated Immunogenicity to Recombinant Methioninase in Primates
Authors: Yang Zhijian , Wang Junhua , Lu Quan , Xu Jinbao , Kobayashi Yoshinao , Takakura Tomoaki , Takimoto Akio , Yoshioka Takayuji , Lian Changgen , Chen Chunmei , Zhang Dongdong , Zhang Ying , Li Shukuan , Sun Xinghua , Tan Yuying , Yagi Shigeo , Frenkel Eugene P. , Hoffman Robert M.
Published: September 2005

Methionine depletion by recombinant methioninase (rMETase) has been demonstrated previously to be highly effective in tumor-bearing mouse models. However, the therapeutic potential of rMETase has been limited by its short plasma half-life and immunologic effects, including high antibody production in mice and monkeys and anaphylactic reactions in monkeys. To overcome these limits of rMETase, the enzyme has been coupled to methoxypolyethylene glycol succinimidyl glutarate (MEGC-PEG-5000). In this study, we evaluated the pharmacokinetics, antigenicity and toxicity of MEGC-PEG-rMETase in Macaca fascicularis monkeys using an escalating-dose strategy. Dose ranging studies at 1,000, 4,000, and 8,000 units/kg i.v. determined that a single dose of 4,000 units/kg was sufficient to reduce plasma methionine to <5 μmol/L for 12 hours. Pharmacokinetic analysis with the single 4,000 units/kg dose showed that MEGC-PEG-rMETase holoenzyme activity was eliminated with a biological half-life of 1.3 hours, and the MEGC-PEG-rMETase apoenzyme was eliminated with a biological half-life of 90 hours, an ∼36-fold increase compared with non-PEGylated rMETase. A single dose at 2,000 units/kg of MEGC-PEG-rMETase resulted in an apoenzyme half-life of 143 hours. A seven-day i.v. administration of 4,000 units/kg every 12 hours resulted in a steady-state depletion of plasma methionine to <5 μmol/L. The only manifest toxicity was decreased food intake and slight weight loss. Red cell values and hemoglobin declined transiently during treatment but recovered after cessation of treatment. Subsequent challenges on days 29, 50 and, 71 did not result in any immunologic reactions. This result is in contrast to non-PEGylated rMETase, which elicited anaphylactic reactions in monkeys. Anti-MEGC-PEG-rMETase antibodies (at 10−2) were found on day 29, and these increased to 10−3 to 104 on day 71, 100 to 1,000-fold less than antibodies elicited by naked rMETase. Although anti-MEGC-PEG-rMETase antibodies were produced, no neutralizing antibody was identified, and each challenge dose was effective in depleting plasma methionine levels. The results of the present study demonstrate that PEGylation greatly prolongs serum half-life of the rMETase apoenzyme and eliminated anaphylactic reactions. The results indicate a profile with respect to serum half-life, toxicity, and antigenicity that suggest clinical potential of MEGC-PEG-rMETase.
Protein Kinase C ε Is an Endogenous Photosensitizer That Enhances Ultraviolet Radiation-Induced Cutaneous Damage and Development of Squamous Cell Carcinomas1
Authors: Wheeler Deric L. , Martin Kaitlin E. , Ness Kristin J. , Li Yafan , Dreckschmidt Nancy E. , Wartman Marybeth , Ananthaswamy Honnavara N. , Mitchell David L. , Verma Ajit K.
Published: September 2005

Chronic exposure to UV radiation (UVR), especially in the UVA (315–400 nm) and UVB (280–315 nm) spectrum of sunlight, is the major risk factor for the development of nonmelanoma skin cancer. UVR is a complete carcinogen, which both initiates and promotes carcinogenesis. We found that protein kinase C ε (PKCε), a member of the phospholipid-dependent threonine/serine kinase family, is an endogenous photosensitizer, the overexpression of which in the epidermis increases the susceptibility of mice to UVR-induced cutaneous damage and development of squamous cell carcinoma. The PKCε transgenic mouse (FVB/N) lines 224 and 215 overexpressed 8- and 18-fold PKCε protein, respectively, over endogenous levels in basal epidermal cells. UVR exposure (1 kJ/m2 three times weekly) induced irreparable skin damage in high PKCε-overexpressing mouse line 215. However, the PKCε transgenic mouse line 224, when exposed to UVR (2 kJ/m2 three times weekly), exhibited minimum cutaneous damage but increased squamous cell carcinoma multiplicity by 3-fold and decreased tumor latency by 12 weeks. UVR exposure of PKCε transgenic mice compared with wild-type littermates (1) elevated the levels of neither cyclobutane pyrimidine dimer nor pyrimidine (6-4) pyrimidone dimer, (2) reduced the appearance of sunburn cells, (3) induced extensive hyperplasia and increased the levels of mouse skin tumor promoter marker ornithine decarboxylase, and (4) elevated the levels of tumor necrosis factor α (TNFα) and other growth stimulatory cytokines, granulocyte colony–stimulating factor, and granulocyte macrophage colony–stimulating factor. The role of TNFα in UVR-induced cutaneous damage was evaluated using PKCε transgenic mice deficient in TNFα. UVR treatment three times weekly for 13 weeks at 2 kJ/m2 induced severe cutaneous damage in PKCε transgenic mice (line 215), which was partially prevented in PKCε-transgenic TNFα-knockout mice. Taken together, the results indicate that PKCε signals UVR-induced TNFα release that is linked, at least in part, to the photosensitivity of PKCε transgenic mice.
Human
In vivo
Radiation-Induced Biomarkers
Authors: Amundson Sally A. , Grace Marcy B. , McLeland Christopher B. , Epperly Michael W. , Yeager Andrew , Zhan Qimin , Greenberger Joel S. , Fornace Albert J.
Published: September 2005

After initially identifying potential biomarkers of radiation exposure through microarray studies of ex vivo irradiated human peripheral white blood cells, we have now measured the in vivo responses of several of these biomarker genes in patients undergoing total body irradiation. Microarray analysis has identified additional in vivo radiation-responsive genes, although the general in vivo patterns of stress-gene induction appear similar to those obtained from ex vivo white blood cell experiments. Additional studies may reveal correlations between responses and either diagnosis or prognosis, and such in vivo validation marks an important step in the development of potentially informative radiation exposure biomarkers.
Selective Activation of Insulin Receptor Substrate-1 and -2 in Pleural Mesothelioma Cells
Authors: Hoang Chuong D. , Zhang Xihong , Scott Paul D. , Guillaume Tenner J. , Maddaus Michael A. , Yee Douglas , Kratzke Robert A.
Published: September 2005

Molecular mechanisms active in transforming human pleural cells remain incompletely understood. Our previous microarray analysis of malignant pleural mesothelioma revealed alterations in components of the insulin-like growth factor (IGF) system, implicating this signaling axis in tumorigenesis. Therefore, in this current study, we characterized the molecular phenotype and investigated the key signaling pathways of the IGF system in malignant pleural mesothelioma specimens. For the major IGF components, we assessed mRNA abundance and total protein levels. We measured IGF-I ligand-dependent activation of signaling pathways downstream of the type I IGF receptor in a subset of malignant pleural mesothelioma cell lines and determined the corresponding biological consequences. At the transcriptional level, we observed consistent changes in IGF components that may contribute to a malignant phenotype. IGF-I stimulation of cells resulted in enhanced activation of type I IGF receptor and IRS adaptor proteins. Differential activation of IRS-1 signaling was associated with cell growth, whereas IRS-2 signaling was associated with cell motility. Thus, these data suggest that multiple mechanisms likely contribute to malignant pleural mesothelioma tumorigenesis. Therefore, IGF system components represent novel malignant pleural mesothelioma therapeutic targets for investigation.
Gefitinib Induces Apoptosis in the EGFRL858R Non–Small-Cell Lung Cancer Cell Line H3255
Authors: Tracy Sean , Mukohara Toru , Hansen Mark , Meyerson Matthew , Johnson Bruce E. , Jänne Pasi A.
Published: September 2005

Somatic mutations in the tyrosine kinase domain of the epidermal growth factor receptor (EGFR) have recently been described in patients with non–small-cell lung cancer (NSCLC) who achieve radiographic regressions to the EGFR inhibitor gefitinib. One of these mutations, L858R (Leu→Arg), is also found in NSCLC cell line H3255, which is very sensitive to gefitinib treatment. We characterized nine NSCLC cell lines (three isolated from patients with bronchioloalveolar carcinoma and six isolated from patients with adenocarcinoma) for their in vitro sensitivity to gefitinib. Of these, only H3255 (EGFRL858R) and H1666 (EGFRWT) are sensitive to gefitinib with IC50 values of 40 nmol/L and 2 μmol/L, respectively. We examined the effects of gefitinib on H3255 and cell lines containing wild-type EGFR that are either sensitive (H1666) or resistant (A549 and H441) to gefitinib exposure in vitro. Gefitinib treatment (1 μmol/L) leads to significant apoptosis accompanied by increased poly(ADP-ribose) polymerase cleavage only in the H3255 cell line, leads to G1-S arrest in H1666, and has no effects in the A549 and H441 cell lines. Although EGFR and AKT are constitutively phosphorylated in H3255, H1666, and H441 cell lines, AKT is completely inhibited by gefitinib treatment only in the H3255 cell line. These findings further characterize a mechanism by which gefitinib treatment of NSCLC harboring EGFRL858R leads to a dramatic response to gefitinib.
A Functional Polymorphism in
RGS6
Modulates the Risk of Bladder Cancer
Authors: Berman David M. , Wang Yunfei , Liu Zhengyu , Dong Qiong , Burke Lorri-Anne , Liotta Lance A. , Fisher Rory , Wu Xifeng
Published: September 2005

RGS proteins negatively regulate heterotrimeric G protein signaling. Recent reports have shown that RGS proteins modulate neuronal, cardiovascular, and lymphocytic activity, yet their role in carcinogenesis has not been explored. In an epidemiologic study of 477 bladder cancer patients and 446 matched controls, three noncoding single-nucleotide polymorphisms (SNPs) in RGS2 and RGS6 were each associated with a statistically significant reduction in bladder cancer risk. The risk of bladder cancer was reduced by 74% in those individuals with the variant genotype at all three SNPs (odds ratio, 0.26; 95% confidence interval, 0.09–0.71). When the SNPs were analyzed separately, the RGS6-rs2074647 (C→T) polymorphism conferred the greatest overall reduction in risk of bladder cancer (odds ratio, 0.66; 95% confidence interval, 0.46–0.95). These reductions in risk were more pronounced in ever smokers, suggesting a gene-environment interaction. In transfection assays, the RGS6-rs2074647 (C→T) polymorphism increased the activity of a luciferase-RGS fusion protein by 2.9-fold, suggesting that this SNP is functionally significant. Finally, we demonstrate that RGS2 transcripts and several splice variants of RGS6 are expressed in bladder cancer cells. These data provide the first evidence that RGS proteins may be important modulators of cancer risk and validate RGS6 as a target for further study.
c-Jun NH2-Terminal Kinase Activation Contributes to Hypoxia-Inducible Factor 1α–Dependent P-Glycoprotein Expression in Hypoxia
Authors: Comerford Katrina M. , Cummins Eoin P. , Taylor Cormac T.
Published: September 2005

We previously have shown that hypoxia increases the expression of P-glycoprotein, which in turn increases tumor cell capacity to actively extrude chemotherapeutic agents and may contribute to tumor drug resistance. This event is mediated through the hypoxia-inducible factor (HIF-1). Here, we investigated the role of the stress-activated protein kinase c-Jun NH2-terminal kinase (JNK) in the signaling mechanisms underlying these events. Hypoxia activates JNK activity in vitro and in vivo. Overexpression of mitogen-activated protein kinase (MAPK) kinase kinase (MEKK-1), which preferentially activates JNK, mimics, in a nonadditive way, hypoxia-induced activity of the MDR1 promoter and expression of MDR1 mRNA and P-glycoprotein. Furthermore, the JNK inhibitor SP600125 selectively and specifically inhibits hypoxia- and MEKK-1–induced MDR1 promoter activity in a dose-dependent manner. JNK inhibition also reversed hypoxia- and MEKK-1–induced activity of an HIF-1–dependent reporter gene. MEKK-1–induced MDR1 expression depends on a functional HIF-1 binding site (hypoxia-responsive element). Hypoxia- but not cobalt chloride–dependent HIF-1–DNA binding and transcriptional activation was inhibited by SP600125, indicating that hypoxia-induced signaling to HIF-1 depends on JNK activation. Because it has been reported that reactive oxygen species are increased in hypoxia and related to JNK activation, we investigated their role in signaling this response. Whereas exogenous addition of H2O2 was sufficient to activate JNK, reactive oxygen species scavengers were without effect on hypoxia-induced JNK or HIF-1 activation. Thus, hypoxia-elicited MDR1 expression, which depends on HIF-1 activation, depends at least in part on signaling via activation of JNK. Furthermore, these events are independent of the generation of reactive oxygen intermediates. Thus, JNK may represent a therapeutic target in the prevention of tumor resistance to chemotherapeutic treatment.
Using Sindbis Viral Vectors for Specific Detection and Suppression of Advanced Ovarian Cancer in Animal Models
Authors: Tseng Jen-Chieh , Hurtado Alicia , Yee Herman , Levin Brandi , Boivin Christopher , Benet Marta , Blank Stephanie V. , Pellicer Angel , Meruelo Daniel
Published: September 2005

We studied the therapeutic value of Sindbis vectors for advanced metastatic ovarian cancer by using two highly reproducible and clinically accurate mouse models: a SCID xenograft model, established by i.p. inoculation of human ES-2 ovarian cancer cells, and a syngenic C57BL/6 model, established by i.p. inoculation of mouse MOSEC ovarian cancer cells. We demonstrate through imaging, histologic, and molecular data that Sindbis vectors systemically and specifically infect/detect and kill metastasized tumors in the peritoneal cavity, leading to significant suppression of the carcinomatosis in both animal models. Use of two different bioluminescent genetic markers for the IVIS Imaging System permitted demonstration, for the first time, of an excellent correlation between vector delivery and metastatic locations in vivo. Sindbis vector infection and growth suppression of murine MOSEC tumor cells indicate that Sindbis tumor specificity is not attributable to a species difference between human tumor and mouse normal cells. Sindbis virus is known to infect mammalian cells using the Mr 67,000 laminin receptor. Immunohistochemical staining of tumor cells indicates that laminin receptor is elevated in tumor versus normal cells. Down-regulated expression of laminin receptor with small interfering RNA significantly reduces the infectivity of Sindbis vectors. Tumor overexpression of the laminin receptor may explain the specificity and efficacy that Sindbis vectors demonstrate for tumor cells in vivo. We show that incorporation of antitumor cytokine genes such as interleukin-12 and interleukin-15 genes enhances the efficacy of the vector. These results suggest that Sindbis viral vectors may be promising agents for both specific detection and growth suppression of metastatic ovarian cancer.
Cyclin G2 Dysregulation in Human Oral Cancer
Authors: Kim Yong , Shintani Satoru , Kohno Yohko , Zhang Rong , Wong David T.
Published: September 2005

Using expression microarray, we have previously shown that human cyclin G2 (hCG2) is significantly down-regulated in laser capture microdissected oral cancer epithelia. Western analysis showed detectable hCG2 protein in normal (2 of 2) but not in malignant (4 of 4) oral keratinocyte cell lines. Immunohistochemistry analysis done on oral cancers showed that normal oral mucosa (100%, 12 of 12) and 69.1% (47 of 68) of dysplastic oral epithelia expressed readily detectable hCG2 in the nuclei. However, only 11.1% of oral cancer epithelia (14 of 126) showed mild hCG2 nuclear staining. Interestingly, of the oral cancers devoid of nuclear hCG2 (112 cases), 58 cases (52%) showed cytoplasmic hCG2 immunostaining, whereas the other 54 cases (48%) exhibited neither nuclear nor cytoplasmic hCG2 staining. In vitro functional study by ectopic restoration of hCG2 expression in the human malignant squamous cell carcinoma (SCC) line SCC15 resulted in a significant inhibition of cellular proliferation (P < 0.001) and colony formation (P < 2 × 10−5) with increased population of G1 phase and decreased in S phase (P < 0.01). Furthermore, stable down-regulation of hCG2 by short interference RNA-based gene silencing in immortalized normal oral keratinocytes resulted in enhanced cell growth with increase in S and prominently in G2 phase. Because hCG2 has been implicated as a negative regulator in cell cycle progression, our results support that hCG2 dysregulation may play an important role in epithelial transformation and the early stages of human oral cancer development.
In vivo
Near-Infrared Fluorescence Imaging of Integrin αvβ3 in Brain Tumor Xenografts
Authors: Chen Xiaoyuan , Conti Peter S. , Moats Rex A.
Published: September 2005

Noninvasive visualization of cell adhesion molecule αvβ3 integrin expression in vivo has been well studied by using the radionuclide imaging modalities in various preclinical tumor models. A literature survey indicated no previous use of cyanine dyes as contrast agents for in vivo optical detection of tumor integrin. Herein, we report the integrin receptor specificity of novel peptide-dye conjugate arginine-glycine-aspartic acid (RGD)-Cy5.5 as a contrast agent in vitro, in vivo, and ex vivo. The RGD-Cy5.5 exhibited intermediate affinity for αvβ3 integrin (IC50 = 58.1 ± 5.6 nmol/L). The conjugate led to elevated cell-associated fluorescence on integrin-expressing tumor cells and endothelial cells and produced minimal cell fluorescence when coincubated with c(RGDyK). In vivo imaging with a prototype three-dimensional small-animal imaging system visualized subcutaneous U87MG glioblastoma xenograft with a broad range of concentrations of fluorescent probe administered via the tail vein. The intermediate dose (0.5 nmol) produces better tumor contrast than high dose (3 nmol) and low dose (0.1 nmol) during 30 minutes to 24 hours postinjection, because of partial self-inhibition of receptor-specific tumor uptake at high dose and the presence of significant amount of background fluorescence at low dose, respectively. The tumor contrast was also dependent on the mouse viewing angles. Tumor uptake of RGD-Cy5.5 was blocked by unlabeled c(RGDyK). This study suggests that the combination of the specificity of RGD peptide/integrin interaction with near-infrared fluorescence detection may be applied to noninvasive imaging of integrin expression and monitoring anti-integrin treatment efficacy providing near real-time measurements.
Recombinant
Listeria
Vaccines Containing PEST Sequences Are Potent Immune Adjuvants for the Tumor-Associated Antigen Human Papillomavirus-16 E7
Authors: Sewell Duane A. , Shahabi Vafa , Gunn George R. , Pan Zhen-Kun , Dominiecki Mary E. , Paterson Yvonne
Published: September 2005

Previous work in our laboratory has established that the fusion of tumor-associated antigens to a truncated form of the Listeria monocytogenes virulence factor listeriolysin O (LLO) enhances the immunogenicity and antitumor efficacy of the tumor antigen when delivered by Listeria or by vaccinia. LLO contains a PEST sequence at the NH2 terminus. These sequences, which are found in eukaryotic proteins with a short cellular half-life, target proteins for degradation in the ubiquitin-proteosome pathway. To investigate whether the enhanced immunogenicity conferred by LLO is due to the PEST sequence, we constructed new Listeria recombinants that expressed the HPV-16 E7 antigen fused to LLO, which either contained or had been deleted of this sequence. We then compared the antitumor efficacy of this set of vectors and found that Listeria expressing the fusion protein LLO-E7 or PEST-E7 were effective at regressing established macroscopic HPV-16 immortalized tumors in syngeneic mice. In contrast, Listeria recombinants expressing E7 alone or E7 fused to LLO from which the PEST sequence had been genetically removed could only slow tumor growth. Because CD8+ T cell epitopes are generated in the ubiquitin-proteosome pathway, we also investigated the ability of the vaccines to induce E7-specific CD8+ T cells in the spleen and to generate E7-specific tumor-infiltrating lymphocytes. A strong correlation was observed between CD8+ T-cell induction and tumor homing and the antitumor efficacy of the Listeria-E7 vaccines. These findings suggest a strategy for the augmentation of tumor antigen-based immunotherapeutic strategies that may be broadly applicable.
Alterations in Vascular Gene Expression in Invasive Breast Carcinoma
Authors: Parker Belinda S. , Argani Pedram , Cook Brian P. , Liangfeng Han , Chartrand Scott D. , Zhang Mindy , Saha Saurabh , Bardelli Alberto , Jiang Yide , St. Martin Thia B. , Nacht Mariana , Teicher Beverly A. , Klinger Katherine W. , Sukumar Saraswati , Madden Stephen L.
Published: September 2005

The molecular signature that defines tumor microvasculature will likely provide clues as to how vascular-dependent tumor proliferation is regulated. Using purified endothelial cells, we generated a database of gene expression changes accompanying vascular proliferation in invasive breast cancer. In contrast to normal mammary vasculature, invasive breast cancer vasculature expresses extracellular matrix and surface proteins characteristic of proliferating and migrating endothelial cells. We define and validate the up-regulated expression of VE-cadherin and osteonectin in breast tumor vasculature. In contrast to other tumor types, invasive breast cancer vasculature induced a high expression level of specific transcription factors, including SNAIL1 and HEYL, that may drive gene expression changes necessary for breast tumor neovascularization. We demonstrate the expression of HEYL in tumor endothelial cells and additionally establish the ability of HEYL to both induce proliferation and attenuate programmed cell death of primary endothelial cells in vitro. We also establish that an additional intracellular protein and previously defined metastasis-associated gene, PRL3, appears to be expressed predominately in the vasculature of invasive breast cancers and is able to enhance the migration of endothelial cells in vitro. Together, our results provide unique insights into vascular regulation in breast tumors and suggest specific roles for genes in driving tumor angiogenesis.
Bone Marrow Is a Reservoir for CD4+CD25+ Regulatory T Cells that Traffic through CXCL12/CXCR4 Signals
Authors: Zou Linhua , Barnett Brian , Safah Hana , LaRussa Vincent F. , Evdemon-Hogan Melina , Mottram Peter , Wei Shuang , David Odile , Curiel Tyler J. , Zou Weiping
Published: September 2005

CD4+CD25+ regulatory T cells (Tregs) mediate peripheral T-cell homeostasis and contribute to self-tolerance. Their homeostatic and pathologic trafficking is poorly understood. Under homeostatic conditions, we show a relatively high prevalence of functional Tregs in human bone marrow. Bone marrow strongly expresses functional stromal-derived factor (CXCL12), the ligand for CXCR4. Human Tregs traffic to and are retained in bone marrow through CXCR4/CXCL12 signals as shown in chimeric nonobese diabetic/severe combined immunodeficient mice. Granulocyte colony-stimulating factor (G-CSF) reduces human bone marrow CXCL12 expression in vivo, associated with mobilization of marrow Tregs to peripheral blood in human volunteers. These findings show a mechanism for homeostatic Treg trafficking and indicate that bone marrow is a significant reservoir for Tregs. These data also suggest a novel mechanism explaining reduced acute graft-versus-host disease and improvement in autoimmune diseases following G-CSF treatment.
Respective Roles of Serological Status and Blood Specific Antihuman Herpesvirus 8 Antibody Levels in Human Herpesvirus 8 Intrafamilial Transmission in a Highly Endemic Area
Authors: Plancoulaine Sabine , Abel Laurent , Trégouët David , Duprez Renan , van Beveren Monique , Tortevoye Patricia , Froment Alain , Gessain Antoine
Published: September 2005

Transmission of human herpesvirus 8 (HHV-8), the etiological agent of Kaposi’s sarcoma, occurs mainly during childhood in endemic countries and, to a large extent, through intrafamilial contacts. To additionally investigate this familial transmission, and especially the role of plasma anti-HHV–8 antibody titers, we conducted a large survey in a village from Cameroon, Central Africa, including 92 families (608 individuals). Plasma samples were tested for specific IgG directed against HHV-8 lytic antigens by immunofluorescence assay, and titers were determined by 2-fold dilutions. Global HHV-8 seroprevalence was 60%, raising from 32% under 9 years up to a plateau of around 62% between 15 and 40 years. The familial correlation patterns in HHV-8 seropositive/seronegative status showed strong dependence from mother to child and between siblings. In contrast, no familial correlation in anti-HHV–8 antibody levels was observed among infected subjects. In particular, no relationship was observed between the anti-HHV–8 antibody titer of HHV-8 seropositive mothers and the proportion of their HHV-8 seropositive children. Furthermore, a random permutation study of the anti-HHV–8 antibody titers among HHV-8 infected subjects showed that the main risk factor for infection was the HHV-8 serologic status and not the antibody level. In addition, no correlation was found between anti-HHV–8 antibody levels and buffy coat HHV-8 viral loads in a subsample of 95 infected subjects. Overall, these results strongly suggest that, in this highly endemic population from Central Africa, HHV-8 transmission mainly occurs from mother to child and between siblings, and it is independent of plasma antibody levels of HHV-8 infected relatives.
Breast Cancer Cells Isolated by Chemotaxis from Primary Tumors Show Increased Survival and Resistance to Chemotherapy
Authors: Goswami Sumanta , Wang Weigang , Wyckoff Jeffrey B. , Condeelis John S.
Published: September 2005

In this study, we have collected a migratory population of carcinoma cells by chemotaxis to epidermal growth factor-containing microneedles held in the primary tumor. The collected cells were subjected to microarray analysis for differential gene expression. The results show that anti-apoptotic genes are up-regulated and pro-apoptotic genes are down-regulated coordinately in the migratory subpopulation. Induction of apoptosis by doxorubicin, cisplatin, and etoposide in these cells demonstrates that they exhibit a lower drug-induced apoptotic index and lower cell death compared with carcinoma cells of the whole tumor. Our study indicates, for the first time, the capability of using a rat alograft model for evaluating the apoptotic status of a migratory subpopulation of tumor cells and the ability to study their resistance to chemotherapeutic agents directly. In addition, these results indicate that tumor cells that are chemotactic and migratory in response to epidermal growth factor in the primary tumor have a survival advantage over stationary tumor cells.
Physical and Functional Interactions between the Wwox Tumor Suppressor Protein and the AP-2γ Transcription Factor
Authors: Aqeilan Rami I. , Palamarchuk Alexey , Weigel Ronald J. , Herrero Juan J. , Pekarsky Yuri , Croce Carlo M.
Published: September 2005

The WWOX gene encodes a tumor suppressor WW domain-containing protein, Wwox. Alterations of WWOX have been demonstrated in multiple types of cancer, and introduction of Wwox into Wwox-negative tumor cells has resulted in tumor suppression and apoptosis. The Wwox protein contains two WW domains that typically bind proline-rich motifs and mediate protein–protein interactions. Recently, we have described functional cross-talk between the Wwox protein and the p53 homologue, p73. To further explore the biological function of Wwox, we investigated other interacting candidates. In this report, we demonstrate a physical and functional association between AP-2γ transcription factor and the Wwox protein. AP-2γ at 20q13.2 encodes a transcription factor and is frequently amplified in breast carcinoma. We show that Wwox binds to the PPPY motif of AP-2γ via its first WW domain. Alterations of tyrosine 33 in the first WW domain of Wwox or the proline-rich motif in AP-2γ dramatically reduce this interaction. In addition, our results demonstrate that Wwox expression triggers redistribution of nuclear AP-2γ to the cytoplasm, hence suppressing its transactivating function. Our results suggest that Wwox tumor suppressor protein inhibits AP-2γ oncogenic activity by sequestering it in the cytoplasm.
BRAK/CXCL14 Is a Potent Inhibitor of Angiogenesis and a Chemotactic Factor for Immature Dendritic Cells
Authors: Shellenberger Thomas D. , Wang Mary , Gujrati Manu , Jayakumar Arumugam , Strieter Robert M. , Burdick Marie D. , Ioannides Constantin G. , Efferson Clayton L. , El-Naggar Adel K. , Roberts Dianna , Clayman Gary L. , Frederick Mitchell J.
Published: September 2005

BRAK/CXCL14 is a CXC chemokine constitutively expressed at the mRNA level in certain normal tissues but absent from many established tumor cell lines and human cancers. Although multiple investigators cloned BRAK, little is known regarding the physiologic function of BRAK or the reason for decreased expression in cancer. To understand the possible significance associated with loss of BRAK mRNA in tumors, we examined the pattern of BRAK protein expression in normal and tumor specimens from patients with squamous cell carcinoma (SCC) of the tongue and used recombinant BRAK (rBRAK) to investigate potential biological functions. Using a peptide-specific antiserum, abundant expression of BRAK protein was found in suprabasal layers of normal tongue mucosa but consistently was absent in tongue SCC. Consistent with previous in situ mRNA studies, BRAK protein also was expressed strongly by stromal cells adjacent to tumors. In the rat corneal micropocket assay, BRAK was a potent inhibitor of in vivo angiogenesis stimulated by multiple angiogenic factors, including interleukin 8, basic fibroblast growth factor, and vascular endothelial growth factor. In vitro, rBRAK blocked endothelial cell chemotaxis at concentrations as low as 1 nmol/L, suggesting this was a major mechanism for angiogenesis inhibition. Although only low affinity receptors for BRAK could be found on endothelial cells, human immature monocyte-derived dendritic cells (iDCs) bound rBRAK with high affinity (i.e., Kd, ∼2 nmol/L). Furthermore, rBRAK was chemotactic for iDCs at concentrations ranging from 1 to 10 nmol/L. Our findings support a hypothesis that loss of BRAK expression from tumors may facilitate neovascularization and possibly contributes to immunologic escape.
CXC Chemokine Receptor 3 Expression by Activated CD8+ T cells Is Associated with Survival in Melanoma Patients with Stage III Disease
Authors: Mullins Irene M. , Slingluff Craig L. , Lee Jae K. , Garbee Courtney F. , Shu Jianfen , Anderson Sara G. , Mayer Melanie E. , Knaus William A. , Mullins David W.
Published: September 2005

Despite the presence of tumor Ag-specific CD8+ T cells in the peripheral blood, metastatic melanoma often evades immune-mediated destruction. Even after therapeutic efforts to expand Ag-specific T-cell populations, the correlation between magnitude of response and clinical efficacy has been weak. Because the migratory phenotype of tumor Ag-specific effector T cells may determine their ability for tumor control, we hypothesized that the expression of CC or CXC chemokine receptor (CCR) molecules on activated CD8+ T cells may define phenotypes associated with more effective control of melanoma progression and prolonged survival. In a retrospective evaluation of patient isolates, CCR expression was determined for activated CD8+ T cells derived from the peripheral blood or tumor-involved lymph nodes of 52 patients with stage III or IV metastatic melanoma. In patients with stage III disease, expression of CXCR3 by CD8+CD45RO+ cells was significantly associated with enhanced survival. This was a stage-specific effect, because it was not observed in patients with stage IV disease. In addition, CCR4 and CXCR3 were highly coexpressed and associated with enhanced survival in stage III patients; however, CXCR3 seems to be the dominant receptor associated with clinical outcome. These findings support the hypothesis that the host immune system affects cancer progression and control, and that measures of CCR status of circulating lymphocytes may have prognostic value.
Gene Expression of Parathyroid Tumors
Authors: Haven Carola J. , Howell Viive M. , Eilers Paul H. C. , Dunne Robert , Takahashi Masayuki , van Puijenbroek Marjo , Furge Kyle , Kievit Job , Tan Min-Han , Fleuren Gert Jan , Robinson Bruce G. , Delbridge Leigh W. , Philips Jeanette , Nelson Anne E. , Krause Ulf , Dralle Henning , Hoang-Vu Cuong , Gimm Oliver , Morreau Hans , Marsh Deborah J. , Teh Bin T.
Published: September 2005

Parathyroid tumors are heterogeneous, and diagnosis is often difficult using histologic and clinical features.

We have undertaken expression profiling of 53 hereditary and sporadic parathyroid tumors to better define the molecular genetics of parathyroid tumors. A class discovery approach identified three distinct groups: (1) predominantly hyperplasia cluster, (2) HRPT2/carcinoma cluster consisting of sporadic carcinomas and benign and malignant tumors from Hyperparathyroidism-Jaw Tumor Syndrome patients, and (3) adenoma cluster consisting mainly of primary adenoma and MEN 1 tumors. Gene sets able to distinguish between the groups were identified and may serve as diagnostic biomarkers. We demonstrated, by both gene and protein expression, that Histone 1 Family 2, amyloid β precursor protein, and E-cadherin are useful markers for parathyroid carcinoma and suggest that the presence of a HRPT2 mutation, whether germ-line or somatic, strongly influences the expression pattern of these 3 genes. Cluster 2, characterized by HRPT2 mutations, was the most striking, suggesting that parathyroid tumors with somatic HRPT2 mutation or tumors developing on a background of germ-line HRPT2 mutation follow pathways distinct from those involved in mutant MEN 1-related parathyroid tumors. Furthermore, our findings likely preclude an adenoma to carcinoma progression model for parathyroid tumorigenesis outside of the presence of either a germ-line or somatic HRPT2 mutation. These findings provide insights into the molecular pathways involved in parathyroid tumorigenesis and will contribute to a better understanding, diagnosis, and treatment of parathyroid tumors.
RASSF4/AD037 Is a Potential Ras Effector/Tumor Suppressor of the RASSF Family
Authors: Eckfeld Kristin , Hesson Luke , Vos Michele D. , Bieche Ivan , Latif Farida , Clark Geoffrey J.
Published: September 2005

Activated Ras proteins interact with a broad range of effector proteins to induce a diverse series of biological consequences. Although typically associated with enhanced growth and transformation, activated Ras may also induce growth antagonistic effects such as senescence or apoptosis. It is now apparent that some of the growth-inhibitory properties of Ras are mediated via the RASSF family of Ras effector/tumor suppressors. To date, four members of this family have been identified (Nore1, RASSF1, RASSF2, and RASSF3). We now identify a fifth member of this group, RASSF4 (AD037). RASSF4 shows approximately 25% identity with RASSF1A and 60% identity with RASSF2. RASSF4 binds directly to activated K-Ras in a GTP-dependent manner via the effector domain, thus exhibiting the basic properties of a Ras effector. Overexpression of RASSF4 induces Ras-dependent apoptosis in 293-T cells and inhibits the growth of human tumor cell lines. Although broadly expressed in normal tissue, RASSF4 is frequently down-regulated by promoter methylation in human tumor cells. Thus, RASSF4 appears to be a new member of the RASSF family of potential Ras effector/tumor suppressors.
Activin Type II Receptor Restoration inACVR2-Deficient Colon Cancer Cells Induces Transforming Growth Factor-β Response Pathway Genes
Authors: Deacu Elena , Mori Yuriko , Sato Fumiaki , Yin Jing , Olaru Andreea , Sterian Anca , Xu Yan , Wang Suna , Schulmann Karsten , Berki Agnes , Kan Takatsugu , Abraham John M. , Meltzer Stephen J.
Published: September 2005

The activin type II receptor (ACVR2) gene is a putative tumor suppressor gene that is frequently mutated in microsatellite-unstable colon cancers (MSI-H colon cancers). ACVR2 is a member of the transforming growth factor (TGF)-β type II receptor (TGFBR2) family and controls cell growth and differentiation. SMAD proteins are major intracellular effectors shared by ACVR2 and TGFBR2 signaling; however, additional shared effector mechanisms remain to be explored. To discover novel mechanisms transmitting the ACVR2 signal, we restored ACVR2 function by transfecting wild-type ACVR2 (wt-ACVR2) into a MSI-H colon cancer cell line carrying an ACVR2 frameshift mutation. The effect of ACVR2 restoration on cell growth, SMAD phosphorylation, and global molecular phenotype was then evaluated. Decreased cell growth was observed in wt-ACVR2 transfectants relative to ACVR2-deficient vector-transfected controls. Western blotting revealed higher expression of phosphorylated SMAD2 in wt-ACVR2 transfectants versus controls, suggesting cells deficient in ACVR2 had impaired SMAD signaling. Microarray-based differential expression analysis revealed substantial ACVR2-induced overexpression of genes implicated in the control of cell growth and tumorigenesis, including the activator protein (AP)-1 complex genes JUND, JUN, and FOSB, as well as the small GTPase signal transduction family members, RHOB, ARHE, and ARHGDIA. Overexpression of these genes is shared with TGFBR2 activation. This observed similarity between the activin and TGF-β signaling systems suggests that activin may serve as an alternative activator of TGF-β effectors, including SMADs, and that frameshift mutation of ACVR2 may contribute to MSI-H colon tumorigenesis via disruption of alternate TGF-β effector pathways.
Id2 Drives Differentiation and Suppresses Tumor Formation in the Intestinal Epithelium
Authors: Russell Robert G. , Lasorella Anna , Dettin Luis E. , Iavarone Antonio
Published: September 2005

Oncogenic signals elevate expression of Id2 in multiple tumor types. When deregulated, Id2 inactivates the tumor suppressor proteins retinoblastoma, p107, and p130. Here, we report a novel and unexpected tumor inhibitory function of Id2 in the intestinal epithelium. First, genetic ablation of Id2 in the mouse prevents differentiation and cell cycle arrest of enterocytes at the time of formation of the crypt-villus unit. Later, these developmental abnormalities evolve toward neoplastic transformation with complete penetrance. Id2-null tumors contain severe dysplastic and metaplastic lesions and express aberrant amounts of β-catenin. Thus, our data are the first to establish a direct requirement of basic helix-loop-helix inhibitors in driving differentiation and define an unexpected role for the retinoblastoma-binding protein Id2 in preventing tumor formation.
Endogenous Inhibitors of Nuclear Factor-κB, An Opportunity for Cancer Control
Authors: Chen Fei
Published: September 2005

Excessive and prolonged activation of nuclear factor-κB (NF-κB) has been linked to numerous human diseases, especially cancer, because of the elevated expression of genes encoding antiapoptotic proteins, cytokines, chemokines, cell adhesion molecules, and so on. Eukaryotic cells have developed multiple mechanisms to keep this ubiquitous transcription factor in check. In addition to the inhibitor of κB family proteins, a number of endogenous molecules that negatively regulate the activation or activity of NF-κB have been identified. These molecules include A20, CYLD, cyPG15-deoxy-Δ12,14-prostaglandin J2, Foxj1, Twist proteins, and β-arrestins. The extended list of these endogenous inhibitors of NF-κB may provide new opportunities for the development of novel strategies for the intervention of malignant transformation. The question to be asked is how NF-κB is sustained activated in a number of cancers in which so many antagonists are surrounded.
Regulation of Protein Catabolism by Muscle-Specific and Cytokine-Inducible Ubiquitin Ligase E3α-II during Cancer Cachexia
Authors: Kwak Keith S. , Zhou Xiaolan , Solomon Vered , Baracos Vickie E. , Davis James , Bannon Anthony W. , Boyle William J. , Lacey David L. , Han H.Q.
Published: September 2005

The progressive depletion of skeletal muscle is a hallmark of many types of advanced cancer and frequently is associated with debility, morbidity, and mortality. Muscle wasting is primarily mediated by the activation of the ubiquitin-proteasome system, which is responsible for degrading the bulk of intracellular proteins. E3 ubiquitin ligases control polyubiquitination, a rate-limiting step in the ubiquitin-proteasome system, but their direct involvement in muscle protein catabolism in cancer remains obscure. Here, we report the full-length cloning of E3α-II, a novel “N-end rule” ubiquitin ligase, and its functional involvement in cancer cachexia. E3α-II is highly enriched in skeletal muscle, and its expression is regulated by proinflammatory cytokines. In two different animal models of cancer cachexia, E3α-II was significantly induced at the onset and during the progression of muscle wasting. The E3α-II activation in skeletal muscle was accompanied by a sharp increase in protein ubiquitination, which could be blocked by arginine methylester, an E3α-selective inhibitor. Treatment of myotubes with tumor necrosis factor α or interleukin 6 elicited marked increases in E3α-II but not E3α-I expression and ubiquitin conjugation activity in parallel. E3α-II transfection markedly accelerated ubiquitin conjugation to endogenous cellular proteins in muscle cultures. These findings show that E3α-II plays an important role in muscle protein catabolism during cancer cachexia and suggest that E3α-II is a potential therapeutic target for muscle wasting.
Schedule-dependent Inhibition of Hypoxia-inducible Factor-1α Protein Accumulation, Angiogenesis, and Tumor Growth by Topotecan in U251-HRE Glioblastoma Xenografts
Authors: Rapisarda Annamaria , Zalek Jessica , Hollingshead Melinda , Braunschweig Till , Uranchimeg Badarch , Bonomi Carrie A. , Borgel Suzanne D. , Carter John P. , Hewitt Stephen M. , Shoemaker Robert H. , Melillo Giovanni
Published: September 2005

We have previously shown that topotecan, a topoisomerase I poison, inhibits hypoxia-inducible factor (HIF)-1α protein accumulation by a DNA damage-independent mechanism. Here, we report that daily administration of topotecan inhibits HIF-1α protein expression in U251-HRE glioblastoma xenografts. Concomitant with HIF-1α inhibition, topotecan caused a significant tumor growth inhibition associated with a marked decrease of angiogenesis and expression of HIF-1 target genes in tumor tissue. These results provide a compelling rationale for testing topotecan in clinical trials to target HIF-1 in cancer patients.