bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Potential Role of Jun Activation Domain–Binding Protein 1 as a Negative Regulator of p27kip1 in Pancreatic Adenocarcinoma
Authors: Kouvaraki Maria A. , Korapati Anita L. , Rassidakis George Z. , Tian Ling , Zhang Qingxiu , Chiao Paul , Ho Linus , Evans Douglas B. , Claret François X.
Published: March 2023

Abstract
Reduced expression of p27 has been associated with poor prognosis in most human cancers, including pancreatic adenocarcinoma. Jun activation domain–binding protein 1 (JAB1), an activator protein (AP-1) coactivator, previously implicated in p27 degradation, is overexpressed in various tumors and correlates with low p27 expression. We examined JAB1 and p27 in normal and neoplastic pancreatic tissues. Increased JAB1 expression was seen in pancreatic carcinoma samples but not in paired normal pancreatic tissues. Immunohistochemical analysis using tissue microarrays showed that JAB1 was overexpressed in all 32 (100%) pancreatic adenocarcinoma samples tested, predominantly nuclear in 23 (72%) samples and predominantly cytoplasmic in 9 (28%) tumors. When 10% was used as a cutoff for p27 positivity, p27 was expressed in 11 (34%) of tumors; however, p27 expression was localized in the nuclei of tumor cells in only 4 (13%) of the samples. Overexpression of the JAB1 in the pancreatic carcinoma cell lines Panc-1, Mia PaCa-2, and Panc-28 resulted in decreased p27 expression. Conversely, down-regulation of JAB1 by short interfering RNA substantially increased p27 expression and inhibited progression from G1 to S phase of the cell cycle. Interestingly, JAB1-mediated p27 degradation was not impaired when S-phase kinase-interacting protein 2 (Skp2), an F-box protein required for the ubiquitination and consequent degradation of p27, was silenced. Thus, JAB1 may have an Skp2-independent p27 degradation mechanism in pancreatic cancer cells. These findings suggest that JAB1 overexpression is involved in the pathogenesis of pancreatic cancer through JAB1-mediated p27 degradation and that control of JAB1 expression is a novel therapeutic target in patients with pancreatic adenocarcinomas. (Cancer Res 2006; 66(17): 8581-9)
Data from High Frequency of Coexistent Mutations of PIK3CA and PTEN Genes in Endometrial Carcinoma
Authors: Oda Katsutoshi , Stokoe David , Taketani Yuji , McCormick Frank
Published: March 2023

Abstract
The phosphatidylinositol 3′-kinase (PI3K) pathway is activated in many human cancers. In addition to inactivation of the PTEN tumor suppressor gene, mutations or amplifications of the catalytic subunit α of PI3K (PIK3CA) have been reported. However, the coexistence of mutations in these two genes seems exceedingly rare. As PTEN mutations occur at high frequency in endometrial carcinoma, we screened 66 primary endometrial carcinomas for mutations in the helical and catalytic domains of PIK3CA. We identified a total of 24 (36%) mutations in this gene and coexistence of PIK3CA/PTEN mutations at high frequency (26%). PIK3CA mutations were more common in tumors with PTEN mutations (17 of 37, 46%) compared with those without PTEN mutations (7 of 29, 24%). Array comparative genomic hybridization detected 3q24-qter amplification, which covers the PIK3CA gene (3q26.3), in one of nine tumors. Knocking down PTEN expression in the HEC-1B cell line, which possesses both K-Ras and PIK3CA mutations, further enhances phosphorylation of Akt (Ser473), indicating that double mutation of PIK3CA and PTEN has an additive effect on PI3K activation. Our data suggest that the PI3K pathway is extensively activated in endometrial carcinomas, and that combination of PIK3CA/PTEN alterations might play an important role in development of these tumors.
Data from Degradation of Human Exonuclease 1b upon DNA Synthesis Inhibition
Authors: El-Shemerly Mahmoud , Janscak Pavel , Hess Daniel , Jiricny Josef , Ferrari Stefano
Published: March 2023

Abstract
In response to DNA damage, signaling pathways are triggered that either block the cell division cycle at defined transitions (G1-S and G2-M) or slow down progression through the S phase. Nucleases play important roles in DNA synthesis, recombination, repair, and apoptosis. In this study, we have examined the regulation of human exonuclease 1 (hEXO1b). The endogenous hEXO1b protein was only detected upon enrichment by immunoprecipitation. We found that hEXO1b was constantly expressed throughout the cell cycle. However, treatment of cells with agents that cause arrest of DNA replication led to rapid degradation of hEXO1b. This effect was fully reversed upon removal of the block. Analysis of synchronized cells showed that degradation of hEXO1b during the S phase was strictly dependent on DNA synthesis inhibition. DNA damage caused by UV-C radiation, ionizing radiation, cisplatin, or the alkylating agent N-methyl-N′-nitro-N-nitrosoguanidine did not affect hEXO1b stability. We show that hEXO1b was phosphorylated in response to inhibition of DNA synthesis and that phosphorylation coincided with rapid protein degradation through ubiquitin-proteasome pathways. Our data support the evidence that control of exonuclease 1 activity may be critical for the maintenance of stalled replication forks.
Data from Sequence-Specific Knockdown of EWS-FLI1 by Targeted, Nonviral Delivery of Small Interfering RNA Inhibits Tumor Growth in a Murine Model of Metastatic Ewing's Sarcoma
Authors: Hu-Lieskovan Siwen , Heidel Jeremy D. , Bartlett Derek W. , Davis Mark E. , Triche Timothy J.
Published: March 2023

Abstract
The development of effective, systemic therapies for metastatic cancer is highly desired. We show here that the systemic delivery of sequence-specific small interfering RNA (siRNA) against the EWS-FLI1 gene product by a targeted, nonviral delivery system dramatically inhibits tumor growth in a murine model of metastatic Ewing's sarcoma. The nonviral delivery system uses a cyclodextrin-containing polycation to bind and protect siRNA and transferrin as a targeting ligand for delivery to transferrin receptor–expressing tumor cells. Removal of the targeting ligand or the use of a control siRNA sequence eliminates the antitumor effects. Additionally, no abnormalities in interleukin-12 and IFN-α, liver and kidney function tests, complete blood counts, or pathology of major organs are observed from long-term, low-pressure, low-volume tail-vein administrations. These data provide strong evidence for the safety and efficacy of this targeted, nonviral siRNA delivery system.
Data from Mammalian Target of Rapamycin Inhibition Promotes Response to Epidermal Growth Factor Receptor Kinase Inhibitors in PTEN-Deficient and PTEN-Intact Glioblastoma Cells
Authors: Wang Maria Y. , Lu Kan V. , Zhu Shaojun , Dia Ederlyn Q. , Vivanco Igor , Shackleford Gregory M. , Cavenee Webster K. , Mellinghoff Ingo K. , Cloughesy Timothy F. , Sawyers Charles L. , Mischel Paul S.
Published: March 2023

Abstract
The epidermal growth factor receptor (EGFR) is commonly amplified, overexpressed, and mutated in glioblastoma, making it a compelling molecular target for therapy. We have recently shown that coexpression of EGFRvIII and PTEN protein by glioblastoma cells is strongly associated with clinical response to EGFR kinase inhibitor therapy. PTEN loss, by dissociating inhibition of the EGFR from downstream phosphatidylinositol 3-kinase (PI3K) pathway inhibition, seems to act as a resistance factor. Because 40% to 50% of glioblastomas are PTEN deficient, a critical challenge is to identify strategies that promote responsiveness to EGFR kinase inhibitors in patients whose tumors lack PTEN. Here, we show that the mammalian target of rapamycin (mTOR) inhibitor rapamycin enhances the sensitivity of PTEN-deficient tumor cells to the EGFR kinase inhibitor erlotinib. In two isogenic model systems (U87MG glioblastoma cells expressing EGFR, EGFRvIII, and PTEN in relevant combinations, and SF295 glioblastoma cells in which PTEN protein expression has been stably restored), we show that combined EGFR/mTOR kinase inhibition inhibits tumor cell growth and has an additive effect on inhibiting downstream PI3K pathway signaling. We also show that combination therapy provides added benefit in promoting cell death in PTEN-deficient tumor cells. These studies provide strong rationale for combined mTOR/EGFR kinase inhibitor therapy in glioblastoma patients, particularly those with PTEN-deficient tumors. (Cancer Res 2006; 66(16): 7864-9)
Data from Epidermal Growth Factor Receptor Signaling Is Up-regulated in Human Colonic Aberrant Crypt Foci
Authors: Cohen Greg , Mustafi Reba , Chumsangsri Anusara , Little Nathaniel , Nathanson Jeff , Cerda Sonia , Jagadeeswaran Sujatha , Dougherty Urszula , Joseph Loren , Hart John , Yerian Lisa , Tretiakova Maria , Yuan Weihua , Obara Piotr , Khare Sharad , Sinicrope Frank A. , Fichera Alessandro , Boss Gerry R. , Carroll Robert , Bissonnette Marc
Published: March 2023

Abstract
Aberrant crypt foci (ACF) are collections of abnormal colonic crypts with heterogeneous molecular and pathologic characteristics. Large and dysplastic ACF are putative precursors of colon cancer with neoplastic risk related to increased proliferation. In this study, we examined the role of epidermal growth factor receptor (EGFR) signaling in regulating ACF proliferation. Using magnification chromoendoscopy, we collected large ACF with endoscopic features of dysplasia and separately biopsied adjacent mucosa. Transcript levels were measured by real-time PCR, proteins were assessed by Western blotting, and levels were expressed as fold changes of adjacent mucosa. K-ras and B-Raf mutations were assessed by PCR and Ras activation by the ratio Ras-GTP / (Ras-GTP + Ras-GDP). At the RNA level, 38% of ACF were hyperproliferative, with proliferating cell nuclear antigen (PCNA) mRNA ≥2-fold of adjacent mucosa. Hyperproliferative ACF had significantly increased mRNA levels of EGFR (6.0 ± 1.7–fold), transforming growth factor-α (14.4 ± 5.0–fold), heparin-binding EGF-like growth factor (4.5 ± 1.4–fold), cyclin D1 (4.6 ± 0.7–fold), and cyclooxygenase-2 (COX-2; 9.3 ± 4.2–fold; P < 0.05). At the protein level, 46% of ACF were hyperproliferative (PCNA, 3.2 ± 1.2–fold). In hyperproliferative ACF, 44% possessed significant increases in four EGFR signaling components: EGFR (9.5 ± 1.3–fold), phosphoactive ErbB2 (2.6 ± 0.4–fold), phosphoactive extracellular signal-regulated kinase (3.7 ± 1.1–fold), and cyclin D1 (3.4 ± 0.8–fold; P < 0.05). Ras was activated in 46% of ACF (3.2 ± 0.4–fold; P < 0.05), but K-ras mutations were present in only 7% of ACF. In contrast to COX-2 mRNA, the protein was not increased in hyperproliferative ACF. In summary, we have shown that ACF with up-regulated PCNA possess increased EGFR signaling components that likely contribute to the enhanced proliferative state of dysplastic-appearing ACF. (Cancer Res 2006; 66(11): 5656-64)
Data from Large-scale Transcriptome Analyses Reveal New Genetic Marker Candidates of Head, Neck, and Thyroid Cancer
Authors: Reis Eduardo M. , Ojopi Elida P.B. , Alberto Fernando L. , Rahal Paula , Tsukumo Fernando , Mancini Ulises M. , Guimarães Gustavo S. , Thompson Gloria M.A. , Camacho Cleber , Miracca Elisabete , Carvalho André L. , Machado Abimael A. , Paquola Apuã C.M. , Cerutti Janete M. , da Silva Aline M. , Pereira Gonçalo G. , Valentini Sandro R. , Nagai Maria A. , Kowalski Luiz Paulo , Verjovski-Almeida Sergio , Tajara Eloiza H. , Dias-Neto Emmanuel
Published: March 2023

Abstract
A detailed genome mapping analysis of 213,636 expressed sequence tags (EST) derived from nontumor and tumor tissues of the oral cavity, larynx, pharynx, and thyroid was done. Transcripts matching known human genes were identified; potential new splice variants were flagged and subjected to manual curation, pointing to 788 putatively new alternative splicing isoforms, the majority (75%) being insertion events. A subset of 34 new splicing isoforms (5% of 788 events) was selected and 23 (68%) were confirmed by reverse transcription–PCR and DNA sequencing. Putative new genes were revealed, including six transcripts mapped to well-studied chromosomes such as 22, as well as transcripts that mapped to 253 intergenic regions. In addition, 2,251 noncoding intronic RNAs, eventually involved in transcriptional regulation, were found. A set of 250 candidate markers for loss of heterozygosis or gene amplification was selected by identifying transcripts that mapped to genomic regions previously known to be frequently amplified or deleted in head, neck, and thyroid tumors. Three of these markers were evaluated by quantitative reverse transcription–PCR in an independent set of individual samples. Along with detailed clinical data about tumor origin, the information reported here is now publicly available on a dedicated Web site as a resource for further biological investigation. This first in silico reconstruction of the head, neck, and thyroid transcriptomes points to a wealth of new candidate markers that can be used for future studies on the molecular basis of these tumors. Similar analysis is warranted for a number of other tumors for which large EST data sets are available.
Data from Inhibition of Phosphatidylinositol 3-Kinase Destabilizes Mycn Protein and Blocks Malignant Progression in Neuroblastoma
Authors: Chesler Louis , Schlieve Chris , Goldenberg David D. , Kenney Anna , Kim Grace , McMillan Alex , Matthay Katherine K. , Rowitch David , Weiss William A.
Published: March 2023

Abstract
Amplification of MYCN occurs commonly in neuroblastoma. We report that phosphatidylinositol 3-kinase (PI3K) inhibition in murine neuroblastoma (driven by a tyrosine hydroxylase-MYCN transgene) led to decreased tumor mass and decreased levels of Mycn protein without affecting levels of MYCN mRNA. Consistent with these observations, PI3K inhibition in MYCN-amplified human neuroblastoma cell lines resulted in decreased levels of Mycn protein without affecting levels of MYCN mRNA and caused decreased proliferation and increased apoptosis. To clarify the importance of Mycn as a target of broad-spectrum PI3K inhibitors, we transduced wild-type N-myc and N-myc mutants lacking glycogen synthase kinase 3β phosphorylation sites into human neuroblastoma cells with no endogenous expression of myc. In contrast to wild-type N-myc, the phosphorylation-defective mutant proteins were stabilized and were resistant to the antiproliferative effects of PI3K inhibition. Our results show the importance of Mycn as a therapeutic target in established tumors in vivo, offer a mechanistic rationale to test PI3K inhibitors in MYCN-amplified neuroblastoma, and represent a therapeutic approach applicable to a broad range of cancers in which transcription factors are stabilized through a PI3K-dependent mechanism. (Cancer Res 2006; 66(16): 8139-46)
Data from Cross-Talk between Nucleotide Excision and Homologous Recombination DNA Repair Pathways in the Mechanism of Action of Antitumor Trabectedin
Authors: Herrero Ana B. , Martín-Castellanos Cristina , Marco Esther , Gago Federico , Moreno Sergio
Published: March 2023

Abstract
Trabectedin (Yondelis) is a potent antitumor drug that has the unique characteristic of killing cells by poisoning the DNA nucleotide excision repair (NER) machinery. The basis for the NER-dependent toxicity has not yet been elucidated but it has been proposed as the major determinant for the drug's cytotoxicity. To study the in vivo mode of action of trabectedin and to explore the role of NER in its cytotoxicity, we used the fission yeast Schizosaccharomyces pombe as a model system. Treatment of S. pombe wild-type cells with trabectedin led to cell cycle delay and activation of the DNA damage checkpoint, indicating that the drug causes DNA damage in vivo. DNA damage induced by the drug is mostly caused by the NER protein, Rad13 (the fission yeast orthologue to human XPG), and is mainly repaired by homologous recombination. By constructing different rad13 mutants, we show that the DNA damage induced by trabectedin depends on a 46–amino acid region of Rad13 that is homologous to a DNA-binding region of human nuclease FEN-1. More specifically, an arginine residue in Rad13 (Arg961), conserved in FEN1 (Arg314), was found to be crucial for the drug's cytotoxicity. These results lead us to propose a model for the action of trabectedin in eukaryotic cells in which the formation of a Rad13/DNA-trabectedin ternary complex, stabilized by Arg961, results in cell death. (Cancer Res 2006; 66(16): 8155-62)
Data from Progression of Barrett's Metaplasia to Adenocarcinoma Is Associated with the Suppression of the Transcriptional Programs of Epidermal Differentiation
Authors: Kimchi Erik T. , Posner Mitchell C. , Park James O. , Darga Thomas E. , Kocherginsky Masha , Karrison Theodore , Hart John , Smith Kerrington D. , Mezhir James J. , Weichselbaum Ralph R. , Khodarev Nikolai N.
Published: March 2023

Abstract
We did expressional profiling on 24 paired samples of normal esophageal epithelium, Barrett's metaplasia, and esophageal adenocarcinomas. Matching tissue samples representing the three different histologic types were obtained from each patient undergoing esophagectomy for adenocarcinoma. Our analysis compared the molecular changes accompanying the transformation of normal squamous epithelium with Barrett's esophagus and adenocarcinoma in individual patients rather than in a random cohort. We tested the hypothesis that expressional profiling may reveal gene sets that can be used as molecular markers of progression from normal esophageal epithelium to Barrett's esophagus and adenocarcinoma. Expressional profiling was done using U133A GeneChip (Affymetrix), which represent approximately two thirds of the human genome. The final selection of 214 genes permitted the discrimination of differential gene expression of normal esophageal squamous epithelium, Barrett's esophagus, and adenocarcinoma using two-dimensional hierarchical clustering of selected genes. These data indicate that transformation of Barrett's esophagus to adenocarcinoma is associated with suppression of the genes involved in epidermal differentiation, including genes in 1q21 loci and corresponding to the epidermal differentiation complex. Correlation analysis of genes concordantly expressed in Barrett's esophagus and adenocarcinoma revealed 21 genes that represent potential genetic markers of disease progression and pharmacologic targets for treatment intervention. PCR analysis of genes selected based on DNA array experiments revealed that estimation of the ratios of GATA6 to SPRR3 allows discrimination among normal esophageal epithelium, Barrett's dysplasia, and adenocarcinoma.
Data from BiP/GRP78 Is an Intracellular Target for MDA-7/IL-24 Induction of Cancer-Specific Apoptosis
Authors: Gupta Pankaj , Walter Mark R. , Su Zao-zhong , Lebedeva Irina V. , Emdad Luni , Randolph Aaron , Valerie Kristoffer , Sarkar Devanand , Fisher Paul B.
Published: March 2023

Abstract
Melanoma differentiation-associated gene-7/interleukin-24 (mda-7/IL-24) is a unique member of the IL-10 gene family that induces cancer-selective growth suppression and apoptosis in a wide spectrum of human cancers in cell culture and animal models. Additionally, recent clinical trials confirm safety and document significant clinical activity of mda-7/IL-24 in patients with diverse solid cancers and melanomas. Despite intensive study the molecular basis of tumor-cell selectivity of mda-7/IL-24 is not well characterized. Using deletion analysis, a specific mutant of MDA-7/IL-24, M4, consisting of amino acids 104 to 206, is described that retains the cancer-specific growth-suppressive and apoptosis-inducing properties of the full-length protein. Employing rationally designed mutational analysis, we show that MDA-7/IL-24 and M4 physically interact with BiP/GRP78 through their C and F helices, localize in the endoplasmic reticulum, and activate p38 MAPK and GADD gene expression, culminating in cancer-selective apoptosis. These studies provide novel mechanistic insights into the discriminating antitumor activity of MDA-7/IL-24 by elucidating BiP/GRP78 as a defined intracellular target of action and present an unparalleled opportunity to develop improved therapeutic versions of this cancer-specific apoptosis-inducing cytokine. (Cancer Res 2006; 66(16): 8182-91)
Data from Identification of Potential Human Oncogenes by Mapping the Common Viral Integration Sites in Avian Nephroblastoma
Authors: Pajer Petr , Pečenka Vladimír , Králová Jarmila , Karafiát Vít , Průková Dana , Zemanová Zdena , Kodet Roman , Dvořák Michal
Published: March 2023

Abstract
Gene deregulation is a frequent cause of malignant transformation. Alteration of the gene structure and/or expression leading to cellular transformation and tumor growth can be experimentally achieved by insertion of the retroviral genome into the host DNA. Retrovirus-containing host loci found repeatedly in clonal tumors are called common viral integration sites (cVIS). cVIS are located in genes or chromosomal regions whose alterations participate in cellular transformation. Here, we present the chicken model for the identification of oncogenes and tumor suppressor genes in solid tumors by mapping the cVIS. Using the combination of inverse PCR and long terminal repeat-rapid amplification of cDNA ends technique, we have analyzed 93 myeloblastosis-associated virus type 2–induced clonal nephroblastoma tumors in detail, and mapped >500 independent retroviral integration sites. Eighteen genomic loci were hit repeatedly and thus classified as cVIS, five of these genomic loci have previously been shown to be involved in malignant transformation of different human cell types. The expression levels of selected genes and their human orthologues have been assayed in chicken and selected human renal tumor samples, and their possible correlation with tumor development, has been suggested. We have found that genes associated with cVIS are frequently, but not in all cases, deregulated at the mRNA level as a result of proviral integration. Furthermore, the deregulation of their human orthologues has been observed in the samples of human pediatric renal tumors. Thus, the avian nephroblastoma is a valid source of cancer-associated genes. Moreover, the results bring deeper insight into the molecular background of tumorigenesis in distant species. (Cancer Res 2006; 66(1): 78-86)
Data from Identifying Allelic Loss and Homozygous Deletions in Pancreatic Cancer without Matched Normals Using High-Density Single-Nucleotide Polymorphism Arrays
Authors: Calhoun Eric S. , Hucl Tomas , Gallmeier Eike , West Kristen M. , Arking Dan E. , Maitra Anirban , Iacobuzio-Donahue Christine A. , Chakravarti Aravinda , Hruban Ralph H. , Kern Scott E.
Published: March 2023

Abstract
Recent advances in oligonucleotide arrays and whole-genome complexity reduction data analysis now permit the evaluation of tens of thousands of single-nucleotide polymorphisms simultaneously for a genome-wide analysis of allelic status. Using these arrays, we created high-resolution allelotype maps of 26 pancreatic cancer cell lines. The areas of heterozygosity implicitly served to reveal regions of allelic loss. The array-derived maps were verified by a panel of 317 microsatellite markers used in a subset of seven samples, showing a 97.1% concordance between heterozygous calls. Three matched tumor/normal pairs were used to estimate the false-negative and potential false-positive rates for identifying loss of heterozygosity: 3.6 regions (average minimal region of loss, 720,228 bp) and 2.3 regions (average heterozygous gap distance, 4,434,994 bp) per genome, respectively. Genomic fractional allelic loss calculations showed that cumulative levels of allelic loss ranged widely from 17.1% to 79.9% of the haploid genome length. Regional increases in “NoCall” frequencies combined with copy number loss estimates were used to identify 41 homozygous deletions (19 first reports), implicating an additional 13 regions disrupted in pancreatic cancer. Unexpectedly, 23 of these occurred in just two lines (BxPc3 and MiaPaCa2), suggesting the existence of at least two subclasses of chromosomal instability (CIN) patterns, distinguished here by allelic loss and copy number changes (original CIN) and those also highly enriched in the genomic “holes” of homozygous deletions (holey CIN). This study provides previously unavailable high-resolution allelotype and deletion breakpoint maps in widely shared pancreatic cancer cell lines and effectively eliminates the need for matched normal tissue to define informative loci. (Cancer Res 2006; 66(16): 7920-9)
Data from Helicobacter Infection Is Required for Inflammation and Colon Cancer in Smad3-Deficient Mice
Authors: Maggio-Price Lillian , Treuting Piper , Zeng Weiping , Tsang Mark , Bielefeldt-Ohmann Helle , Iritani Brian M.
Published: March 2023

Abstract
Accumulating evidence suggests that intestinal microbial organisms may play an important role in triggering and sustaining inflammation in individuals afflicted with inflammatory bowel disease (IBD). Moreover, individuals with IBD are at increased risk for developing colorectal cancer, suggesting that chronic inflammation may initiate genetic or epigenetic changes associated with cancer development. We tested the hypothesis that bacteria may contribute to the development of colon cancer by synergizing with defective transforming growth factor-β (TGF-β) signaling, a pathway commonly mutated in human colon cancer. Although others have reported that mice deficient in the TGF-β signaling molecule SMAD3 develop colon cancer, we found that SMAD3-deficient mice maintained free of the Gram-negative enterohepatic bacteria Helicobacter spp. for up to 9 months do not develop colon cancer. Furthermore, infection of SMAD3−/− mice with Helicobacter triggers colon cancer in 50% to 66% of the animals. Using real-time PCR, we found that Helicobacter organisms concentrate in the cecum, the preferred site of tumor development. Mucinous adenocarcinomas develop 5 to 30 weeks after infection and are preceded by an early inflammatory phase, consisting of increased proliferation of epithelial cells; increased numbers of cyclooxygenase-2–positive cells, CD4+ T cells, macrophages; and increased MHC class II expression. Colonic tissue revealed increased transcripts for the oncogene c-myc and the proinflammatory cytokines interleukin-1α (IL-1α), IL-1β, IL-6, IFN-γ, and tumor necrosis factor-α, some of which have been implicated in colon cancer. These results suggest that bacteria may be important in triggering colorectal cancer, notably in the context of gene mutations in the TGF-β signaling pathway, one of the most commonly affected cellular pathways in colorectal cancer in humans. (Cancer Res 2006; 66(2): 828-38)
Data from The Shaping of a Polyvalent and Highly Individual T-Cell Repertoire in the Bone Marrow of Breast Cancer Patients
Authors: Sommerfeldt Nora , Schütz Florian , Sohn Christoph , Förster Joanna , Schirrmacher Volker , Beckhove Philipp
Published: March 2023

Abstract
We analyzed the T-cell repertoires from the bone marrow of 39 primary operated breast cancer patients and 11 healthy female donors for the presence and frequencies of spontaneously induced effector/memory T lymphocytes with peptide-HLA-A2-restricted reactivity against 10 breast tumor-associated antigens (TAA) and 3 normal breast tissue–associated antigens by short-term IFN-γ enzyme-linked immunospot (ELISpot) analysis. Sixty-seven percent of the patients recognized TAAs with a mean frequency of 144 TAA reactive cells per 106 T cells. These patients recognized simultaneously an average of 47% of the tested TAAs. The T-cell repertoire was highly polyvalent and exhibited pronounced interindividual differences in the pattern of TAAs recognized by each patient. Strong differences of reactivity were noticed between TAAs, ranging from 100% recognition of prostate-specific antigenp141-149 to only 25% recognition of MUC1p12-20 or Her-2/neup369-377. In comparison with TAAs, reactivity to normal breast tissue–associated antigens was lower with respect to the proportions of responding patients (30%) and recognized antigens (27%), with a mean frequency of only 85/106 T cells. Healthy individuals also contained TAA-reactive T cells but this repertoire was more restricted and the frequencies were in the same range as T cells reacting to normal breast tissue–associated antigens. Our data show a highly individual T-cell repertoire for recognition of TAAs in breast cancer patients. This has potential relevance for T-cell immune diagnostics, for tumor vaccine design, and for predicting immune responsiveness. (Cancer Res 2006; 66(16): 8258-65)
Data from A t(1;19)(q10;p10) Mediates the Combined Deletions of 1p and 19q and Predicts a Better Prognosis of Patients with Oligodendroglioma
Authors: Jenkins Robert B. , Blair Hilary , Ballman Karla V. , Giannini Caterina , Arusell Robert M. , Law Mark , Flynn Heather , Passe Sandra , Felten Sara , Brown Paul D. , Shaw Edward G. , Buckner Jan C.
Published: March 2023

Abstract
Combined deletion of chromosomes 1p and 19q is associated with improved prognosis and responsiveness to therapy in patients with anaplastic oligodendroglioma. The deletions usually involve whole chromosome arms, suggesting a t(1;19)(q10;p10). Using stem cell medium, we cultured a few tumors. Paraffin-embedded tissue was obtained from 21 Mayo Clinic patients and 98 patients enrolled in 2 North Central Cancer Treatment Group (NCCTG) low-grade glioma trials. Interphase fusion of CEP1 and 19p12 probes detected the t(1;19). 1p/19q deletions were evaluated by fluorescence in situ hybridization. Upon culture, one oligodendroglioma contained an unbalanced 45,XX,t(1;19)(q10;p10). CEP1/19p12 fusion was observed in all metaphases and 74% of interphase nuclei. Among Mayo Clinic oligodendrogliomas, the prevalence of fusion was 81%. Among NCCTG patients, CEP1/19p12 fusion prevalence was 55%, 47%, and 0% among the oligodendrogliomas, mixed oligoastrocytomas, and astrocytomas, respectively. Ninety-one percent of NCCTG gliomas with 1p/19q deletion and 12% without 1p/19q deletion had CEP1/19p12 fusion (P < 0.001, χ2 test). The median overall survival (OS) for all patients was 8.1 years without fusion and 11.9 years with fusion (P = 0.003). The median OS for patients with low-grade oligodendroglioma was 9.1 years without fusion and 13.0 years with fusion (P = 0.01). Similar significant median OS differences were observed for patients with combined 1p/19q deletions. The absence of alterations was associated with a significantly shorter OS for patients who received higher doses of radiotherapy. Our results strongly suggest that a t(1;19)(q10;p10) mediates the combined 1p/19q deletion in human gliomas. Like combined 1p/19q deletion, the 1;19 translocation is associated with superior OS and progression-free survival in low-grade glioma patients. (Cancer Res 2006; 66(20): 9852-61)
Data from Post-Transcriptional Regulation of the Androgen Receptor by Mammalian Target of Rapamycin
Authors: Cinar Bekir , De Benedetti Arrigo , Freeman Michael R.
Published: March 2023

Abstract
Heparin-binding epidermal growth factor-like growth factor (HB-EGF), an ErbB1 ligand and prostate stromal growth factor, is an antagonist of androgen receptor (AR) function. In the LNCaP prostate cancer model, HB-EGF reduced AR protein levels and AR transactivation without affecting AR mRNA level or protein turnover. The signal to attenuate AR was mediated by the mammalian target of rapamycin, as shown by genetic and pharmacologic methods, and was independent of ErbB2/HER-2, extracellular signal-regulated kinase 1/2, and p38 mitogen-activated protein kinase pathways. Additional evidence suggests that AR protein levels are highly sensitive to regulation by cap-dependent mRNA translation. These findings reveal a novel mechanism for regulation of AR by a classic growth factor system and indicate that a rapamycin-sensitive post-transcriptional pathway can attenuate or possibly bypass AR-mediated signaling.
Data from An Imprinted Locus Epistatically Influences Nstr1 and Nstr2 to Control Resistance to Nerve Sheath Tumors in a Neurofibromatosis Type 1 Mouse Model
Authors: Reilly Karlyne M. , Broman Karl W. , Bronson Roderick T. , Tsang Shirley , Loisel Dagan A. , Christy Emily S. , Sun Zhonghe , Diehl John , Munroe David J. , Tuskan Robert G.
Published: March 2023

Abstract
Cancer is a complex disease in which cells acquire many genetic and epigenetic alterations. We have examined how three types of alterations, mutations in tumor suppressor genes, changes in an imprinted locus, and polymorphic loci, interact to affect tumor susceptibility in a mouse model of neurofibromatosis type 1 (NF1). Mutations in tumor suppressor genes such as TP53 and in oncogenes such as KRAS have major effects on tumorigenesis due to the central roles of these genes in cell proliferation and cell survival. Imprinted genes expressed from only one parental chromosome affect tumorigenesis if their monoallelic expression is lost or duplicated. Because imprinted loci are within regions deleted or amplified in cancer, the parental origin of genomic rearrangements could affect tumorigenesis. Gene polymorphisms can vary tumor incidence by affecting rate-limiting steps in tumorigenesis within tumor cells or surrounding stroma. In our mouse model of NF1, the incidence of tumors mutant for the tumor suppressor genes Nf1 and Trp53 is strongly modified by a linked imprinted locus acting epistatically on two unlinked polymorphic loci, Nstr1 and Nstr2. This interaction of an imprinted locus and polymorphic susceptibility loci has profound implications for human mapping studies where the parental contribution of alleles is often unknown. (Cancer Res 2006; 66(1): 62-8)
Data from Effect of Conditional Knockout of the Type II TGF-β Receptor Gene in Mammary Epithelia on Mammary Gland Development and Polyomavirus Middle T Antigen Induced Tumor Formation and Metastasis
Authors: Forrester Elizabeth , Chytil Anna , Bierie Brian , Aakre Mary , Gorska Agnieszka E. , Sharif-Afshar Ali-Reza , Muller William J. , Moses Harold L.
Published: March 2023

Abstract
Transforming growth factor–β (TGF-β) isoforms are growth factors that function physiologically to regulate development, cellular proliferation, and immune responses. The role of TGF-β signaling in mammary tumorigenesis is complex, as TGF-β has been reported to function as both a tumor suppressor and tumor promoter. To elucidate the role of TGF-β signaling in mammary gland development, tumorigenesis, and metastasis, the gene encoding type II TGF-β receptor, Tgfbr2, was conditionally deleted in the mammary epithelium (Tgfbr2MGKO). Loss of Tgfbr2 in the mammary epithelium results in lobular-alveolar hyperplasia in the developing mammary gland and increased apoptosis. Tgfbr2MGKO mice were mated to the mouse mammary tumor virus-polyomavirus middle T antigen (PyVmT) transgenic mouse model of metastatic breast cancer. Loss of Tgfbr2 in the context of PyVmT expression results in a shortened median tumor latency and an increased formation of pulmonary metastases. Thus, our studies support a tumor-suppressive role for epithelial TGF-β signaling in mammary gland tumorigenesis and show that pulmonary metastases can occur and are even enhanced in the absence of TGF-β signaling in the carcinoma cells.
Data from Regulation of Human Nitric Oxide Synthase 2 Expression by Wnt β-Catenin Signaling
Authors: Du Qiang , Park Kyung Soo , Guo Zhong , He Peijun , Nagashima Makoto , Shao Lifang , Sahai Rohit , Geller David A. , Hussain S. Perwez
Published: March 2023

Abstract
Nitric oxide (NO·), an important mediator of inflammation, and β-catenin, a component of the Wnt–adenomatous polyposis coli signaling pathway, contribute to the development of cancer. We have identified two T-cell factor 4 (Tcf-4)-binding elements (TBE1 and TBE2) in the promoter of human inducible NO synthase 2 (NOS2). We tested the hypothesis that β-catenin regulates human NOS2 gene. Mutation in either of the two TBE sites decreased the basal and cytokine-induced NOS2 promoter activity in different cell lines. The promoter activity was significantly reduced when both TBE1 and TBE2 sites were mutated (P < 0.01). Nuclear extract from HCT116, HepG2, or DLD1 cells bound to NOS2 TBE1 or TBE2 oligonucleotides in electrophoretic mobility shift assays and the specific protein-DNA complexes were supershifted with anti-β-catenin or anti-Tcf-4 antibody. Overexpression of β-catenin and Tcf-4 significantly increased both basal and cytokine-induced NOS2 promoter activity (P < 0.01), and the induction was dependent on intact TBE sites. Overexpression of β-catenin or Tcf-4 increased NOS2 mRNA and protein expression in HCT116 cells. Lithium chloride (LiCl), an inhibitor of glycogen synthase kinase-3β, increased cytosolic and nuclear β-catenin level, NOS2 expression, and NO· production in primary human and rat hepatocytes and cancer cell lines. Treatment with Wnt-3A-conditioned medium increased β-catenin and NOS2 expression in fetal human hepatocytes. When administered in vivo, LiCl increased hepatic β-catenin level in a dose-dependent manner with simultaneous increase in NOS2 expression. These data are consistent with the hypothesis that β-catenin up-regulates NOS2 and suggest a novel mechanism by which the Wnt/β-catenin signaling pathway may contribute to cancer by increasing NO· production. (Cancer Res 2006; 66(14): 7024-31)
Data from The Synovial Sarcoma–Associated SS18-SSX2 Fusion Protein Induces Epigenetic Gene (De)Regulation
Authors: de Bruijn Diederik R.H. , Allander Susanne V. , van Dijk Anke H.A. , Willemse Marieke P. , Thijssen Jose , van Groningen Jan J.M. , Meltzer Paul S. , Geurts van Kessel Ad
Published: March 2023

Abstract
Fusion of the SS18 and either one of the SSX genes is a hallmark of human synovial sarcoma. The SS18 and SSX genes encode nuclear proteins that exhibit opposite transcriptional activities. The SS18 protein functions as a transcriptional coactivator and is associated with the SWI/SNF complex, whereas the SSX proteins function as transcriptional corepressors and are associated with the polycomb complex. The domains involved in these opposite transcriptional activities are retained in the SS18-SSX fusion proteins. Here, we set out to determine the direct transcriptional consequences of conditional SS18-SSX2 fusion protein expression using complementary DNA microarray-based profiling. By doing so, we identified several clusters of SS18-SSX2–responsive genes, including a group of genes involved in cholesterol synthesis, which is a general characteristic of malignancy. In addition, we identified a group of SS18-SSX2–responsive genes known to be specifically deregulated in primary synovial sarcomas, including IGF2 and CD44. Furthermore, we observed an uncoupling of EGR1, JUNB, and WNT signaling in response to SS18-SSX2 expression, suggesting that the SWI/SNF-associated coactivation functions of the SS18 moiety are impaired. Finally, we found that SS18-SSX2 expression affects histone modifications in the CD44 and IGF2 promoters and DNA methylation levels in the IGF2 imprinting control region. Together, we conclude that the SS18-SSX2 fusion protein may act as a so-called transcriptional “activator-repressor,” which induces downstream target gene deregulation through epigenetic mechanisms. Our results may have implications for both the development and clinical management of synovial sarcomas. (Cancer Res 2006; 66(19): 9474-82)
Data from Hypoxia-Induced Down-regulation of BRCA1 Expression by E2Fs
Authors: Bindra Ranjit S. , Gibson Shannon L. , Meng Alice , Westermark Ulrica , Jasin Maria , Pierce Andrew J. , Bristow Robert G. , Classon Marie K. , Glazer Peter M.
Published: March 2023

Abstract
Decreased BRCA1 expression in the absence of genetic mutation is observed frequently in sporadic cancers of the breast and other sites, although little is known regarding the mechanisms by which the expression of this gene can be repressed. Here, we show that activating and repressive E2Fs simultaneously bind the BRCA1 promoter at two adjacent E2F sites in vivo, and that hypoxia induces a dynamic redistribution of promoter occupancy by these factors resulting in the transcriptional repression of BRCA1 expression. Functionally, we show that hypoxia is associated with impaired homologous recombination, whereas the nonhomologous end-joining (NHEJ) repair pathway is unaffected under these conditions. Repression of BRCA1 expression by hypoxia represents an intriguing mechanism of functional BRCA1 inactivation in the absence of genetic mutation. We propose that hypoxia-induced decreases in BRCA1 expression and consequent suppression of homologous recombination may lead to genetic instability by shifting the balance between the high-fidelity homologous recombination pathway and the error-prone NHEJ pathway of DNA repair. Furthermore, these findings provide a novel link between E2Fs and the transcriptional response to hypoxia and provide insight into the mechanisms by which the tumor microenvironment can contribute to genetic instability in cancer. (Cancer Res 2005; 65(24): 11597-604)
Data from ROS Fusion Tyrosine Kinase Activates a SH2 Domain–Containing Phosphatase-2/Phosphatidylinositol 3-Kinase/Mammalian Target of Rapamycin Signaling Axis to Form Glioblastoma in Mice
Authors: Charest Al , Wilker Erik W. , McLaughlin Margaret E. , Lane Keara , Gowda Ram , Coven Shanie , McMahon Kevin , Kovach Steven , Feng Yun , Yaffe Michael B. , Jacks Tyler , Housman David
Published: March 2023

Abstract
Glioblastoma multiforme is the most common and lethal form of primary brain cancer. Diagnosis of this advanced glioma has a poor prognosis due to the ineffectiveness of current therapies. Aberrant expression of receptor tyrosine kinases (RTK) in glioblastoma multiformes is suggestive of their role in initiation and maintenance of these tumors of the central nervous system. In fact, ectopic expression of the orphan RTK ROS is a frequent event in human brain cancers, yet the pathologic significance of this expression remains undetermined. Here, we show that a glioblastoma-associated, ligand-independent rearrangement product of ROS (FIG-ROS) cooperates with loss of the tumor suppressor gene locus Ink4a;Arf to produce glioblastomas in the mouse. We show that this FIG-ROS-mediated tumor formation in vivo parallels the activation of the tyrosine phosphatase SH2 domain–containing phosphatase-2 (SHP-2) and a phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin signaling axis in tumors and tumor-derived cell lines. We have established a fully penetrant preclinical model for adult onset of glioblastoma multiforme in keeping with major genetic events observed in the human disease. These findings provide novel and important insights into the role of ROS and SHP-2 function in solid tumor biology and set the stage for preclinical testing of targeted therapeutic approaches. (Cancer Res 2006; 66(15): 7473-81)
Data from Activated Tyrosine Kinase Ack1 Promotes Prostate Tumorigenesis: Role of Ack1 in Polyubiquitination of Tumor Suppressor Wwox
Authors: Mahajan Nupam P. , Whang Young E. , Mohler James L. , Earp H. Shelton
Published: March 2023

Abstract
Aberrant activation of tyrosine kinases is linked causally to human cancers. Activated Cdc42-associated kinase (Ack1), an intracellular tyrosine kinase, has primarily been studied for its signaling properties but has not been linked to specific pathologic conditions. Herein, we report that expression of activated Ack1 in LNCaP cells, while minimally increasing growth in culture, enhanced anchorage-independent growth in vitro and dramatically accelerated tumorigenesis in nude mice. Molecular chaperone heat shock protein 90β (Hsp90β)–bound Ack1 and treatment of cells with geldanamycin, a Hsp90 inhibitor, inhibited Ack1 kinase activity and suppressed tumorigenesis. Further, we identify the tumor suppressor WW domain containing oxidoreductase (Wwox) as an Ack1-interacting protein. Activated Ack1 tyrosine phosphorylated Wwox, leading to rapid dissociation of the Ack1-Wwox complex and concomitant Wwox polyubiquitination followed by degradation. Tyrosine phosphorylation of Wwox was critical for its degradation, as splice variant WwoxΔ5-8 that was not phosphorylated by Ack1 failed to undergo polyubiquitination and degradation. It has been reported that phosphorylation of Wwox at Tyr33 stimulated its proapoptotic activity. We observed that Y33F Wwox mutant was still tyrosine phosphorylated and polyubiquitinated by Ack1 action. Site-directed mutagenesis revealed that activated Ack1 primarily phosphorylated Wwox at Tyr287, suggesting that phosphorylation of distinct tyrosine residues activate or degrade Wwox. Primary androgen-independent prostate tumors but not benign prostate showed increased tyrosine-phosphorylated Ack1 and decreased Wwox. Taken together, these data indicate that Ack1 stimulated prostate tumorigenesis in part by negatively regulating the proapoptotic tumor suppressor, Wwox. Further, these findings suggest that Ack1 could be a novel therapeutic target for prostate cancer.
Data from Genetically Induced Pancreatic Adenocarcinoma Is Highly Immunogenic and Causes Spontaneous Tumor-Specific Immune Responses
Authors: Garbe Annette I. , Vermeer Benjamin , Gamrekelashvili Jaba , Wasielewski Reinhard von , Greten Florian R. , Westendorf Astrid M. , Buer Jan , Schmid Roland M. , Manns Michael P. , Korangy Firouzeh , Greten Tim F.
Published: March 2023

Abstract
Treatment options for pancreatic cancer are limited and often ineffective. Immunotherapeutic approaches are one possible option that needs to be evaluated in appropriate animal models. The aim of the present study was to analyze tumor-specific immune responses in a mouse model of pancreatic cancer, which mimics the human disease closely. C57BL/6 EL-TGF-α × Trp53−/− mice, which develop spontaneous ductal pancreatic carcinoma, were generated. EL-TGF-α × Trp53−/− mice developed spontaneous pancreatic tumors with pathomorphologic features close to the human disease. Tumor-specific CD8+ T-cell responses and IgG responses were analyzed in EL-TGF-α × Trp53−/− mice during tumor development and compared with mice with s.c. growing pancreatic tumors. In contrast to spontaneous pancreatic tumors, cell lines generated from these tumors were rejected after s.c. injection into wild-type mice but not in nude or RAG knockout mice. Direct comparison of spontaneous and s.c. injected tumors revealed an impaired infiltration of CD8+ T cells in spontaneous pancreatic tumors, which was also evident after adoptive transfer of tumor-specific T cells. Intratumoral cytokine secretion of tumor necrosis factor-α, IFN-γ, IL-6, and MCP-1 was lower in spontaneous tumors as well as the number of adoptively transferred tumor-specific T cells. Our data provide clear evidence for tumor-specific immune responses in a genetic mouse model for pancreatic carcinoma. Comparative analysis of s.c. injected tumors and spontaneous tumors showed significant differences in tumor-specific immune responses, which will help in improving current immune-based cancer therapies against adenocarcinoma of the pancreas. (Cancer Res 2006; 66(1): 508-16)