bluuebunny/crossref_metadata_2025_split huggingface dataset:
Methylation of Polycomb Target Genes in Intestinal Cancer Is Mediated by Inflammation
Authors: Hahn Maria A. , Hahn Torsten , Lee Dong-Hyun , Esworthy R. Steven , Kim Byung-wook , Riggs Arthur D. , Chu Fong-Fong , Pfeifer Gerd P. 
Published: December 2008

AbstractEpigenetic changes are strongly associated with cancer development. DNA hypermethylation is associated with gene silencing and is often observed in CpG islands. Recently, it was suggested that aberrant CpG island methylation in tumors is directed by Polycomb (PcG) proteins. However, specific mechanisms responsible for methylation of PcG target genes in cancer are not known. Chronic infection and inflammation contribute to up to 25% of all cancers worldwide. Using glutathione peroxidase, Gpx1 and Gpx2, double knockout (Gpx1/2-KO) mice as a model of inflammatory bowel disease predisposing to intestinal cancer, we analyzed genome-wide DNA methylation in the mouse ileum during chronic inflammation, aging, and cancer. We found that inflammation leads to aberrant DNA methylation in PcG target genes, with 70% of the ∼250 genes methylated in the inflamed tissue being PcG targets in embryonic stem cells and 59% of the methylated genes being marked by H3K27 trimethylation in the ileum of adult wild-type mice. Acquisition of DNA methylation at CpG islands in the ileum of Gpx1/2-KO mice frequently correlates with loss of H3K27 trimethylation at the same loci. Inflammation-associated DNA methylation occurs preferentially in tissue-specific silent genes and, importantly, is much more frequently represented in tumors than is age-dependent DNA methylation. Sixty percent of aberrant methylation found in tumors is also present in the inflamed tissue. In summary, inflammation creates a signature of aberrant DNA methylation, which is observed later in the malignant tissue and is directed by the PcG complex. [Cancer Res 2008;68(24):10280–9]
The Innate Immune Receptor Nod1 Protects the Intestine from Inflammation-Induced Tumorigenesis
Authors: Chen Grace Y. , Shaw Michael H. , Redondo Gloria , Núñez Gabriel 
Published: December 2008

Abstract
There is growing evidence that the host innate immune system has a critical role in regulating carcinogenesis, but the specific receptors involved and the importance of their interaction with commensal bacteria need to be elucidated. Two major classes of innate immune receptors, the Toll-like receptors and Nod-like receptors, many of which are upstream of nuclear factor-κB, are involved in the detection of intestinal bacteria. The Toll-like receptors have been implicated in promoting colon tumorigenesis, but the role of Nod-like receptors in regulating tumorigenesis remains unclear. Using an established mouse model system of colitis-associated colon tumorigenesis, we show that Nod1 deficiency results in the increased development of both colitis-associated and Apc tumor suppressor–related colon tumors. In the absence of Nod1 signaling, there is a greater disruption of the intestinal epithelial cell barrier due to chemically induced injury as manifested by increased surface epithelial apoptosis early on during chemically induced colitis and increased intestinal permeability. The increased intestinal permeability is associated with enhanced inflammatory cytokine production and epithelial cell proliferation in Nod1-deficient mice as compared with wild-type mice. Depletion of the gut microbiota suppressed tumor development in Nod1-deficient mice, thus highlighting a link between the commensal bacteria within the intestine and the host innate immune Nod1 signaling pathway in the regulation inflammation-mediated colon cancer development. [Cancer Res 2008;68(24):10060–7]
The High-Mobility Group A1a/Signal Transducer and Activator of Transcription-3 Axis: An Achilles Heel for Hematopoietic Malignancies?
Authors: Hillion Joelle , Dhara Surajit , Sumter Takita Felder , Mukherjee Mita , Di Cello Francescopaolo , Belton Amy , Turkson James , Jaganathan Souyma , Cheng Linzhao , Ye Zhaohui , Jove Richard , Aplan Peter , Lin Ying-Wei , Wertzler Kelsey , Reeves Ray , Elbahlouh Ossama , Kowalski Jeanne , Bhattacharya Raka , Resar Linda M. S. 
Published: December 2008

Abstract
Although HMGA1 (high-mobility group A1; formerly HMG-I/Y) is an oncogene that is widely overexpressed in aggressive cancers, the molecular mechanisms underlying transformation by HMGA1 are only beginning to emerge. HMGA1 encodes the HMGA1a and HMGA1b protein isoforms, which function in regulating gene expression. To determine how HMGA1 leads to neoplastic transformation, we looked for genes regulated by HMGA1 using gene expression profile analysis. Here, we show that the STAT3 gene, which encodes the signaling molecule signal transducer and activator of transcription 3 (STAT3), is a critical downstream target of HMGA1a. STAT3 mRNA and protein are up-regulated in fibroblasts overexpressing HMGA1a and activated STAT3 recapitulates the transforming activity of HMGA1a in fibroblasts. HMGA1a also binds directly to a conserved region of the STAT3 promoter in vivo in human leukemia cells by chromatin immunoprecipitation and activates transcription of the STAT3 promoter in transfection experiments. To determine if this pathway contributes to HMGA1-mediated transformation, we investigated STAT3 expression in our HMGA1a transgenic mice, all of which developed aggressive lymphoid malignancy. STAT3 expression was increased in the leukemia cells from our transgenics but not in control cells. Blocking STAT3 function induced apoptosis in the transgenic leukemia cells but not in controls. In primary human leukemia samples, there was a positive correlation between HMGA1a and STAT3 mRNA. Moreover, blocking STAT3 function in human leukemia or lymphoma cells led to decreased cellular motility and foci formation. Our results show that the HMGA1a–STAT3 axis is a potential Achilles heel that could be exploited therapeutically in hematopoietic and other malignancies overexpressing HMGA1a. [Cancer Res 2008;68(24):10121–7]
Wnt5A Regulates Expression of Tumor-Associated Antigens in Melanoma via Changes in Signal Transducers and Activators of Transcription 3 Phosphorylation
Authors: Dissanayake Samudra K. , Olkhanud Purevdorj B. , O'Connell Michael P. , Carter Arnell , French Amanda D. , Camilli Tura C. , Emeche Chineye D. , Hewitt Kyle J. , Rosenthal Devin T. , Leotlela Poloko D. , Wade Michael S. , Yang Sherry W. , Brant Larry , Nickoloff Brian J. , Messina Jane L. , Biragyn Arya , Hoek Keith S. , Taub Dennis D. , Longo Dan L. , Sondak Vernon K. , Hewitt Stephen M. , Weeraratna Ashani T. 
Published: December 2008

Abstract
There are currently no effective therapies for metastatic melanoma and targeted immunotherapy results in the remission of only a very small percentage of tumors. In this study, we show that the noncanonical Wnt ligand, Wnt5A, can increase melanoma metastasis in vivo while down-regulating the expression of tumor-associated antigens important in eliciting CTL responses (e.g., MART-1, GP100, and tyrosinase). Melanosomal antigen expression is governed by MITF, PAX3, and SOX10 and is inhibited upon signal transducers and activators of transcription 3 (STAT3) activation, via decreases in PAX3 and subsequently MITF expression. Increasing Wnt5A in Wnt5A-low cells activated STAT3, and STAT3 was decreased upon Wnt5A knockdown. Downstream targets such as PAX3, MITF, and MART-1 were also affected by Wnt5A treatment or knockdown. Staining of a melanoma tissue array also highlighted the inverse relationship between MART-1 and Wnt5A expression. PKC activation by phorbol ester mimicked Wnt5A effects, and Wnt5A treatment in the presence of STAT3 or PKC inhibitors did not lower MART-1 levels. CTL activation studies showed that increases in Wnt5A correspond to decreased CTL activation and vice versa, suggesting that targeting Wnt5A before immunotherapy may lead to the enhancement of current targeted immunotherapy for patients with metastatic melanoma. [Cancer Res 2008;68(24):10205–14]
In vivo Dynamics of Stable Chronic Lymphocytic Leukemia Inversely Correlate with Somatic Hypermutation Levels and Suggest No Major Leukemic Turnover in Bone Marrow
Authors: van Gent Rogier , Kater Arnon P. , Otto Sigrid A. , Jaspers A. , Borghans José A.M. , Vrisekoop Nienke , Ackermans Mariëtte A.T. , Ruiter An F.C. , Wittebol Shulamiet , Eldering Eric , van Oers Marinus H.J. , Tesselaar Kiki , Kersten Marie José , Miedema Frank 
Published: December 2008

Abstract
Although accumulating evidence indicates that chronic lymphocytic leukemia (CLL) is a disease with appreciable cell dynamics, it remains uncertain whether this also applies to patients with stable disease. In this study, 2H2O was administered to a clinically homogeneous cohort of nine stable, untreated CLL patients. CLL dynamics in blood and bone marrow were determined and compared with normal B-cell dynamics in blood from five healthy individuals who underwent a similar 2H2O labeling protocol. Average CLL turnover rates (0.08–0.35% of the clone per day) were ∼2-fold lower than average B-cell turnover rates from healthy individuals (0.34–0.89%), whereas the rate at which labeled CLL cells in blood disappeared (0.00–0.39% of B cells per day) was ∼10-fold lower compared with labeled B cells from healthy individuals (1.57–4.24% per day). Leukemic cell turnover variables inversely correlated with the level of somatic hypermutation of the CLL clone (IgVH mutations). Although CLL cells in bone marrow had a higher level of label enrichment than CLL cells in blood, no difference between proliferation rates and proapoptotic and antiapoptotic profiles of CLL cells from these compartments was observed. These data suggest that, in stable disease, there is a biological relationship between the degree of somatic hypermutation of the CLL clone and its dynamics in vivo. Furthermore, in contrast to lymph nodes, the bone marrow does not seem to be a major CLL proliferation site. [Cancer Res 2008;68(24):10137–44]
Increased c-Jun-NH2-Kinase Signaling in Neurofibromatosis-1 Heterozygous Microglia Drives Microglia Activation and Promotes Optic Glioma Proliferation
Authors: Daginakatte Girish C. , Gianino Scott M. , Zhao Nina W. , Parsadanian Alexander S. , Gutmann David H. 
Published: December 2008

Abstract
Neurofibromatosis-1 (NF1) is a common tumor predisposition syndrome in which affected individuals develop benign and malignant tumors. Previous studies from our laboratory and others have shown that benign tumor formation in Nf1 genetically engineered mice (GEM) requires a permissive tumor microenvironment. In the central nervous system, Nf1 loss in glia is insufficient for glioma formation unless coupled with Nf1 heterozygosity in the brain. Our subsequent studies identified Nf1+/− microglia as a critical cellular determinant of optic glioma growth in Nf1 GEM. Using NF1 as an experimental paradigm to further characterize the role of microglia in glioma growth, we first examined the properties of Nf1+/− microglia in vitro and in vivo. Nf1+/− microglia exhibit increased proliferation and motility and express elevated levels of genes associated with microglia activation. We further show that Nf1+/− microglia harbor high levels of activated c-Jun-NH2-kinase (JNK) without any significant changes in Akt, mitogen-activated protein kinase (MAPK), or p38-MAPK activity. In contrast, Nf1−/− astrocytes do not exhibit increased JNK activation. SP600125 inhibition of JNK activity in Nf1+/− microglia results in amelioration of the increased proliferation and motility phenotypes and reduces the levels of expression of activated microglia-associated transcripts. Moreover, SP600125 treatment of Nf1 optic glioma–bearing GEM results in reduced optic glioma proliferation in vivo. Collectively, these findings suggest that Nf1+/− microglia represent a good model system to study the role of specialized microglia in brain tumorigenesis and identify a unique Nf1 deregulated pathway for therapeutic studies aimed at abrogating microenvironmental signals that promote brain tumor growth. [Cancer Res 2008;68(24):10358–66]
Genome-wide Allelic State Analysis on Flow-Sorted Tumor Fractions Provides an Accurate Measure of Chromosomal Aberrations
Authors: Corver Willem E. , Middeldorp Anneke , ter Haar Natalja T. , Jordanova Ekaterina S. , van Puijenbroek Marjo , van Eijk Ronald , Cornelisse Cees J. , Fleuren Gert Jan , Morreau Hans , Oosting Jan , van Wezel Tom 
Published: December 2008

Abstract
Chromosomal aberrations are a common characteristic of cancer and are associated with copy number abnormalities and loss of heterozygosity (LOH). Tumor heterogeneity, low tumor cell percentage, and lack of knowledge of the DNA content impair the identification of these alterations especially in aneuploid tumors. To accurately detect allelic changes in carcinomas, we combined flow-sorting and single nucleotide polymorphism arrays. Cells derived from archival cervical and colon cancers were flow-sorted based on differential vimentin and keratin expression and DNA content and analyzed on single nucleotide polymorphism arrays. A new algorithm, the lesser allele intensity ratio, was used to generate a molecular measure of chromosomal aberrations for each case. Flow-sorting significantly improved the detection of copy number abnormalities; 31.8% showed an increase in amplitude and 23.2% were missed in the unsorted fraction, whereas 15.9% were detected but interpreted differently. Integration of the DNA index in the analysis enabled the identification of the allelic state of chromosomal aberrations, such as LOH ([A]), copy-neutral LOH ([AA]), balanced amplifications ([AABB]), and allelic imbalances ([AAB] or [AAAB], etc.). Chromosomal segments were sharply defined. Fluorescence in situ hybridization copy numbers, as well as the high similarity between the DNA index and the allelic state index, which is the average of the allelic states across the genome, validated the method. This new approach provides an individual molecular measure of chromosomal aberrations and will likely have repercussions for preoperative molecular staging, classification, and prognostic profiling of tumors, particularly for heterogeneous aneuploid tumors, and allows the study of the underlying molecular genetic mechanisms and clonal evolution of tumor subpopulations. [Cancer Res 2008;68(24):10333–40]
Phosphorylated Insulin-Like Growth Factor-I/Insulin Receptor Is Present in All Breast Cancer Subtypes and Is Related to Poor Survival
Authors: Law Jennifer H. , Habibi Golareh , Hu Kaiji , Masoudi Hamid , Wang Michelle Y.C. , Stratford Anna L. , Park Eugene , Gee Julia M.W. , Finlay Pauline , Jones Helen E. , Nicholson Robert I. , Carboni Joan , Gottardis Marco , Pollak Michael , Dunn Sandra E. 
Published: December 2008

AbstractDrugs that target the insulin-like growth factor-I receptor (IGF-IR) and/or insulin receptor (IR) are currently under investigation for a variety of malignancies including breast cancer. Although we have previously reported that IGF-IR expression in primary breast tumors is common, the activation status of this receptor has not been examined in relation to survival. Phosphorylated IGF-IR/IR (P-IGF-IR/IR) and its downstream signaling partner phospho-S6 (P-S6) were evaluated immunohistochemically in tumor tissue microarrays representing 438 cases of invasive breast cancer. P-IGF-IR/IR (n = 114; P = 0.046) and total levels of IR (n = 122; P = 0.009) were indicative of poor survival, whereas total IGF-IR (n = 112; P = 0.304) was not. P-IGF-IR/IR and P-S6 were coordinately expressed in primary breast tumors (likelihood ratio, 11.57; P = 6.70 × 10−4). Importantly, P-IGF-IR/IR was detected in all breast cancer subtypes (luminal, 48.1%; triple negative, 41.9%; and HER2, 64.3%). In vitro, the IGF-IR/IR inhibitor BMS-536924 decreased phospho-RSK and P-S6, and significantly suppressed the growth of breast cancer cell lines MCF-7, SUM149, and AU565 representing the luminal, triple negative, and HER2 subtypes, respectively, in monolayer and soft agar. BMS-536924 also inhibited growth in tamoxifen resistant MCF-7 Tam-R cells while having little effect on immortalized normal breast epithelial cells. Thus, we can determine which patients have the activated receptor and provide evidence that P-IGF-IR/IR is a prognostic factor for breast cancer. Beyond this, P-IGF-IR/IR could be a predictive marker for response to IGF-IR and/or IR-targeted therapies, as these inhibitors may be of benefit in all breast cancer subtypes including those with acquired resistance to tamoxifen. [Cancer Res 2008;68(24):10238–46]
Translating an Antagonist of Chemokine Receptor CXCR4: From Bench to Bedside
Authors: Wong Donald , Korz Walter 
Published: December 2008

AbstractThe majority of current cancer therapies focus on a primary tumor approach. However, it is metastases that cause the majority of cancer deaths. The metastatic process has been shown repeatedly to be greatly influenced by chemokines such as CXCL12 [stromal cell derived factor-1 (SDF-1)] and its receptor CXCR4. The activation of this pathway has been reported to modulate cell migration, survival, proliferation, and gene transcription through G proteins, phosphoinositide-3 kinase, Akt, extracellular signal-regulated kinase, arrestin, and Janus-activated kinase/signal transducers and activators of transcription. A wide variety of strategies, such as peptides, small molecules, antibodies, and small interfering RNA, have been used to target this pathway. Treatments in combination with current therapies seem to be especially promising in preclinical studies. A few compounds are advancing into early stages of clinical development. In this article, we will review the development of CXCR4 antagonists in oncology.
Reversal of Myeloid Cell–Mediated Immunosuppression in Patients with Metastatic Renal Cell Carcinoma
Authors: Kusmartsev Sergei , Su Zhen , Heiser Axel , Dannull Jens , Eruslanov Evgeniy , Kübler Hubert , Yancey Donna , Dahm Philip , Vieweg Johannes 
Published: December 2008

AbstractPurpose: Tumor-induced immunosuppression remains a significant obstacle that limits the efficacy of biological therapy for renal cell carcinoma. Here we evaluate the role of CD33 myeloid-derived suppressor cells (MDSC) in the regulation of T-cell responses in renal cell carcinoma patients. We also examine effect of all-trans-retinoic acid (ATRA) on MDSC-mediated immune suppression.Experimental Design: CD33-positive myeloid cells were isolated from the peripheral blood of renal cell carcinoma patients with magnetic beads and tested in vitro for their ability to inhibit T-cell responses. T-cell function was evaluated using ELISPOT and CTL assays.Results: MDSC isolated from renal cell carcinoma patients, but not from healthy donors, were capable of suppressing antigen-specific T-cell responses in vitro through the secretion of reactive oxygen species and nitric oxide upon interaction with CTL. MDSC-mediated immune suppression and IFN-γ down-regulation was reversible in vitro by exposing cells to the reactive oxygen species inhibitors. Moreover, ATRA was capable of abrogating MDSC-mediated immunosuppression and improving T-cell function by direct differentiation into antigen-presenting cell precursors.Conclusions: These results may have significant implications regarding the future design of active immunotherapy protocols that may include differentiation agents as part of a multimodal approach to renal cell carcinoma immunotherapy.
A Phase I and Pharmacokinetic Study of Ixabepilone in Combination with Carboplatin in Patients with Advanced Solid Malignancies
Authors: Plummer Ruth , Woll Penella , Fyfe David , Boddy Alan V. , Griffin Melanie , Hewitt Paula , Carmichael James , Namouni Fouad , Cohen Marvin , Verrill Mark 
Published: December 2008

Abstract
Purpose: To determine the recommended phase II dose of combination ixabepilone plus carboplatin based on the maximum tolerated dose, pharmacokinetics, optimum schedule, and safety.
Experimental Design: Patients with advanced solid malignancies were treated with escalating doses of carboplatin plus ixabepilone administered on day 1 (schedule A) or days 1 and 8 (schedule B) of a 21-day cycle. Blood was sampled during cycle 1 for pharmacokinetic analysis of ixabepilone (both schedules) and carboplatin (schedule B).
Results: Fifty-two patients were treated with ixabepilone doses ranging from 30 to 50 mg/m2 per 21-day cycle plus carboplatin area under curve (AUC) 5 or 6 (Calvert formula). On schedule A (ixabepilone 40 mg/m2 over 1 hour plus carboplatin AUC 6), 2 of 2 patients experienced dose-limiting toxicity (DLT). On schedule B (ixabepilone 25 mg/m2 over 1 hour on days 1 and 8 plus carboplatin AUC 6), 3 of 3 patients experienced DLT. DLT was myelosuppression; however, cumulative sensory neuropathy limited extended dosing on schedule A. Ixabepilone and carboplatin pharmacokinetics were similar to those using either drug as monotherapy, indicating an absence of pharmacokinetic drug interactions. Based on DLTs and tolerability with repeated dosing, the recommended doses were 30 mg/m2 ixabepilone (1-hour infusion) d1 q3w plus carboplatin AUC 6 (schedule A) and 20 mg/m2 ixabepilone (1 hour infusion) d1, d8 q3w plus carboplatin AUC 6 (schedule B).
Conclusions: Data from the present study show the feasibility and tolerability of combination ixabepilone plus carboplatin, with ixabepilone administered on day 1 or on days 1 and 8 on a 21-day cycle.
Cytosolic Phospholipase A2-α: A Potential Therapeutic Target for Prostate Cancer
Authors: Patel Manish I. , Singh Jaskirat , Niknami Marzieh , Kurek Caroline , Yao Mu , Lu Sasa , Maclean Fiona , King Nicholas J.C. , Gelb Michael H. , Scott Kieran F. , Russell Pamela J. , Boulas John , Dong Qihan 
Published: December 2008

Abstract
Purpose: Cytosolic phospholipase A2-α (cPLA2-α) provides intracellular arachidonic acid to supply both cyclooxygenase and lipoxygenase pathways. We aim to determine the expression and activation of cPLA2-α in prostate cancer cell lines and tissue and the effect of targeting cPLA2-α in vitro and in vivo.
Experimental Design: The expression of cPLA2-α was determined in prostate cancer cells by reverse transcription-PCR, Western blot, and immunocytochemistry. Growth inhibition, apoptosis, and cPLA2-α activity were determined after inhibition with cPLA2-α small interfering RNA or inhibitor (Wyeth-1). Cytosolic PLA2-α inhibitor or vehicle was also administered to prostate cancer xenograft mouse models. Finally, the expression of phosphorylated cPLA2-α was determined by immunohistochemistry in human normal, androgen-sensitive and androgen-insensitive prostate cancer specimens.
Results: cPLA2-α is present in all prostate cancer cells lines, but increased in androgen-insensitive cells. Inhibition with small interfering RNA or Wyeth-1 results in significant reductions in prostate cancer cell numbers, as a result of reduced proliferation as well as increased apoptosis, and this was also associated with a reduction in cPLA2-α activity. Expression of cyclin D1 and phosphorylation of Akt were also observed to decrease. Wyeth-1 inhibited PC3 xenograft growth by ∼33% and again, also reduced cyclin D1. Immunohistochemistry of human prostate tissue revealed that phosphorylated cPLA2-α is increased when hormone refractory is reached.
Conclusions: Expression and activation of cPLA2-α are increased in the androgen-insensitive cancer cell line and tissue. Inhibition of cPLA2-α results in cells and xenograft tumor growth inhibition and serves as a potentially effective therapy for hormone refractory prostate cancer.