bluuebunny/crossref_metadata_2025 huggingface dataset:
Epigenetic Signatures of Familial Cancer Are Characteristic of Tumor Type and Family Category
Authors: Joensuu Emmi I. , Abdel-Rahman Wael M. , Ollikainen Miina , Ruosaari Salla , Knuutila Sakari , Peltomäki Päivi
Published: June 2008

Tumor suppressor genes (TSG) may be inactivated by methylation of critical CpG sites in their promoter regions, providing targets for early detection and prevention. Although sporadic cancers, especially colorectal carcinoma (CRC), have been characterized for epigenetic changes extensively, such information in familial/hereditary cancer is limited. We studied 108 CRCs and 63 endometrial carcinomas (EC) occurring as part of hereditary nonpolyposis CRC, as separate familial site-specific entities or sporadically, for promoter methylation of 24 TSGs. Eleven genes in CRC and 6 in EC were methylated in at least 15% of tumors and together accounted for 89% and 82% of promoter methylation events in CRC and EC, respectively. Some genes (e.g., CDH13, APC, GSTP1, and TIMP3) showed frequent methylation in both cancers, whereas promoter methylation of ESR1, CHFR, and RARB was typical of CRC and that of RASSF1(A) characterized EC. Among CRCs, sets of genes with methylation characteristic of familial versus sporadic tumors appeared. A TSG methylator phenotype (methylation of at least 5 of 24 genes) occurred in 37% of CRC and 18% of EC (P = 0.013), and the presence versus absence of MLH1 methylation divided the tumors into high versus low methylation groups. In conclusion, inactivation of TSGs by promoter methylation followed patterns characteristic of tumor type (CRC versus EC) and family category and was strongly influenced by MLH1 promoter methylation status in all categories. Paired normal tissues or blood displayed negligible methylation arguing against a constitutional methylation abnormality in familial cases. [Cancer Res 2008;68(12):4597–605]
GlutathioneS-Transferase P1: Gene Sequence Variation and Functional Genomic Studies
Authors: Moyer Ann M. , Salavaggione Oreste E. , Wu Tse-Yu , Moon Irene , Eckloff Bruce W. , Hildebrandt Michelle A.T. , Schaid Daniel J. , Wieben Eric D. , Weinshilboum Richard M.
Published: June 2008

Glutathione S-transferase P1 (GSTP1) is of importance for cancer research because of its role in detoxifying carcinogens, activating antineoplastic prodrugs, metabolizing chemotherapeutic agents, and its involvement in cell cycle and apoptosis regulation. Two common GSTP1 genetic polymorphisms have been studied extensively. However, the full range of GSTP1 genetic variation has not been systematically characterized in the absence of disease pathology. We set out to identify common GSTP1 polymorphisms in four ethnic groups, followed by functional genomic studies. All exons, splice junctions, and the 5′-flanking region of GSTP1 were resequenced using 60 DNA samples each from four ethnic groups. The 35 single-nucleotide polymorphisms (SNP) identified included six nonsynonymous SNPs and 17 previously unreported polymorphisms. GSTP1 variant allozymes were then expressed in COS-1 cells, and five displayed significantly altered levels of enzyme activity. One decreased to 22% of the wild-type (WT) activity. Four variant allozymes had Km values that differed significantly from that of the WT, and five showed altered levels of immunoreactive protein compared with WT, with a significant correlation (r = 0.79, P < 0.007) between levels of immunoreactive protein and enzyme activity in these samples. In the Mexican American population, five linked SNPs were significantly associated with GSTP1 mRNA expression, one of which was found by electrophoretic mobility shift assay to alter protein binding. These studies have identified functionally significant genetic variation, in addition to the two frequently studied GSTP1 nonsynonymous SNPs, that may influence GSTP1's contribution to carcinogen and drug metabolism, and possibly disease pathogenesis and/or drug response. [Cancer Res 2008;68(12):4791–801]
An HLA-DR–Degenerate Epitope Pool Detects Insulin-like Growth Factor Binding Protein 2–Specific Immunity in Patients with Cancer
Authors: Kalli Kimberly R. , Krco Christopher J. , Hartmann Lynn C. , Goodman Karin , Maurer Matthew J. , Yu Chao , Johnson Elliot M. , Erskine Courtney L. , Disis Mary L. , Wettstein Peter J. , Fikes John D. , Beebe Melanie , Ishioka Glenn , Knutson Keith L.
Published: June 2008

Recent studies have shown the importance of helper CD4 T cells in initiating and sustaining tumor-specific CD8 T-cell immunity. This has paved the way for identifying MHC class II epitopes that could be incorporated into class I–based vaccines. In this study, the goal was to identify an HLA-DR–degenerate epitope pool derived from insulin-like growth factor binding protein 2 (IGFBP-2). IGFBP-2, a regulator of insulin-like growth factor action, is overexpressed in the majority of breast and ovarian cancers. Using algorithms, we predicted 29 HLA-DR1–binding epitopes. Binding assays targeting 15 different HLA-DRs revealed that 10 epitopes were degenerate, binding to at least four different HLA-DR variants. An IFN-γ enzyme-linked immunosorbent spot assay was used to assess immunity to these 10 epitopes in 48 patients with either breast or ovarian cancer and 18 controls. Elevated T-cell immunity in patients was detected in 4 of the 10 epitopes (IGFBP2.17, IGFBP2.22, IGFBP2.249, and IGFBP2.293). The cumulative T-cell frequency of these four epitopes was elevated in patients relative to controls. All four peptides are naturally processed and presented to CD4 T-cells. The degenerate pool of peptides covers nearly 80% of patients and may be useful for augmenting CD4 T-cell immunity in patients undergoing immunization. [Cancer Res 2008;68(12):4893–901]
Elevated CRAF as a Potential Mechanism of Acquired Resistance to BRAF Inhibition in Melanoma
Authors: Montagut Clara , Sharma Sreenath V. , Shioda Toshi , McDermott Ultan , Ulman Matthew , Ulkus Lindsey E. , Dias-Santagata Dora , Stubbs Hannah , Lee Diana Y. , Singh Anurag , Drew Lisa , Haber Daniel A. , Settleman Jeffrey
Published: June 2008

Activating BRAF kinase mutations arise in ∼7% of all human tumors, and preclinical studies have validated the RAF–mitogen-activated protein/extracellular signal-regulated kinase (ERK) kinase–ERK signaling cascade as a potentially important therapeutic target in this setting. Selective RAF kinase inhibitors are currently undergoing clinical development, and based on the experience with other kinase-targeted therapeutics, it is expected that clinical responses to these agents, if observed, will lead to the eventual emergence of drug resistance in most cases. Thus, it is important to establish molecular mechanisms underlying such resistance to develop effective therapeutic strategies to overcome or prevent drug resistance. To anticipate potential mechanisms of acquired resistance to RAF inhibitors during the course of treatment, we established drug-resistant clones from a human melanoma-derived cell line harboring the recurrent V600E activating BRAF mutation, which exhibits exquisite sensitivity to AZ628, a selective RAF kinase inhibitor. We determined that elevated CRAF protein levels account for the acquisition of resistance to AZ628 in these cells, associated with a switch from BRAF to CRAF dependency in tumor cells. We also found that elevated CRAF protein levels may similarly contribute to primary insensitivity to RAF inhibition in a subset of BRAF mutant tumor cells. Interestingly, AZ628-resistant cells demonstrating either primary drug insensitivity or acquired drug resistance exhibit exquisite sensitivity to the HSP90 inhibitor geldanamycin. Geldanamycin effectively promotes the degradation of CRAF, thereby revealing a potential therapeutic strategy to overcome resistance to RAF inhibition in a subset of BRAF mutant tumors. [Cancer Res 2008;68(12):4853–61]
Serine/Arginine Protein–Specific Kinase 2 Promotes Leukemia Cell Proliferation by Phosphorylating Acinus and Regulating Cyclin A1
Authors: Jang Sung-Wuk , Yang Seung-ju , Ehlén Åsa , Dong Shaozhong , Khoury Hanna , Chen Jing , Persson Jenny L. , Ye Keqiang
Published: June 2008

Serine/arginine (SR) protein–specific kinase (SRPK), a family of cell cycle–regulated protein kinases, phosphorylate SR domain–containing proteins in nuclear speckles and mediate the pre-mRNA splicing. However, the physiologic roles of this event in cell cycle are incompletely understood. Here, we show that SRPK2 binds and phosphorylates acinus, an SR protein essential for RNA splicing, and redistributes it from the nuclear speckles to the nucleoplasm, resulting in cyclin A1 but not A2 up-regulation. Acinus S422D, an SRPK2 phosphorylation mimetic, enhances cyclin A1 transcription, whereas acinus S422A, an unphosphorylatable mutant, blocks the stimulatory effect of SRPK2. Ablation of acinus or SRPK2 abrogates cyclin A1 expression in leukemia cells and arrest cells at G1 phase. Overexpression of acinus or SRPK2 increases leukemia cell proliferation. Furthermore, both SRPK2 and acinus are overexpressed in some human acute myelogenous leukemia patients and correlate with elevated cyclin A1 expression levels, fitting with the oncogenic activity of cyclin A1 in leukemia. Thus, our findings establish a molecular mechanism by which SR splicing machinery regulates cell cycle and contributes to leukemia tumorigenesis. [Cancer Res 2008;68(12):4559–70]
Development of a Preclinical Model of Spontaneous Human Melanoma Central Nervous System Metastasis
Authors: Cruz-Munoz William , Man Shan , Xu Ping , Kerbel Robert S.
Published: June 2008

Metastatic spread of melanoma to the central nervous system (CNS) is associated with dismal prognosis. Preclinical testing of novel therapeutic approaches would be aided by the development of appropriate models of spontaneous CNS metastasis arising from primary tumors. A highly metastatic variant of the WM239A human melanoma cell line, designated 113/6-4L, was generated and used to test the efficacy of long-term, low-dose metronomic cyclophosphamide and vinblastine chemotherapy on advanced established metastatic disease in sites such as liver, lungs, and lymph node. This treatment resulted in control of advanced, systemic disease and prolongation of survival. Among long-term surviving mice, 20% showed the presence of spontaneous brain metastases. Two cell lines (131/4-5B1 and 131/4-5B2) were generated from such metastases, which were found to spontaneously metastasize to brain parenchyma with occasional localization to leptomeninges, after orthotopic transplantation and removal of the primary tumor. The cell lines were found to have increased ability to proliferate in brain-conditioned medium and displayed enhanced adhesion to lung and brain endothelial cells. These findings represent the first report of spontaneous CNS metastases generated from primary tumors of any human cancer in mice, which heritably maintains this phenotype, and as such, the variant cell lines generated should aid studies in the biology and treatment of CNS metastases, especially of melanoma origin. [Cancer Res 2008;68(12):4500–5]
Hypoxia Increases Tumor Cell Shedding of MHC Class I Chain-Related Molecule: Role of Nitric Oxide
Authors: Siemens D. Robert , Hu Nianping , Sheikhi Abdol Karim , Chung Eugene , Frederiksen Lisa J. , Pross Hugh , Graham Charles H.
Published: June 2008

The MHC class I chain-related (MIC) molecules play important roles in tumor immune surveillance through their interaction with the NKG2D receptor on natural killer and cytotoxic T cells. Thus, shedding of the MIC molecules from the tumor cell membrane represents a potential mechanism of escape from NKG2D-mediated immune surveillance. Tumor hypoxia is associated with a poor clinical outcome for cancer patients. We show that hypoxia contributes to tumor cell shedding of MIC through a mechanism involving impaired nitric oxide (NO) signaling. Whereas hypoxia increased MIC shedding in human prostate cancer cells, activation of NO signaling inhibited hypoxia-mediated MIC shedding. Similar to incubation in hypoxia, pharmacologic inhibition of endogenous NO signaling increased MIC shedding. Parallel studies showed hypoxia-mediated tumor cell resistance to lysis by interleukin 2–activated peripheral blood lymphocytes (PBL) and NO-mediated attenuation of this resistance to lysis. Inhibition of NO production also led to resistance to PBL-mediated lysis. Interference of MIC-NKG2D interaction with a blocking anti-MIC antibody abrogated the effect of hypoxia and NO signaling on tumor cell sensitivity to PBL-mediated lysis. Finally, continuous transdermal delivery of the NO mimetic glyceryl trinitrate (7.3 μg/h) attenuated the growth of xenografted MIC-expressing human prostate tumors. These findings suggest that the hypoxic tumor microenvironment contributes to resistance to immune surveillance and that activation of NO signaling is of potential use in cancer immunotherapy. [Cancer Res 2008;68(12):4746–53]
Neo-Organoid of Marrow Mesenchymal Stromal Cells Secreting Interleukin-12 for Breast Cancer Therapy
Authors: Eliopoulos Nicoletta , Francois Moïra , Boivin Marie-Noëlle , Martineau Daniel , Galipeau Jacques
Published: June 2008

Bone marrow–derived mesenchymal stromal cells (MSCs), beneficial for regenerative medicine applications due to their wide differentiation capabilities, also hold promise as cellular vehicles for the delivery of therapeutic plasma-soluble gene products due to their ease of handling, expansion, and genetic engineering. We hypothesized that MSCs, gene enhanced to express interleukin-12 (IL-12) and then embedded in a matrix, may act as an anticancer neo-organoid when delivered s.c. in autologous/syngeneic hosts. We performed such experiments in mice and noted that primary murine MSCs retrovirally engineered to secrete murine IL-12 can significantly interfere with growth of 4T1 breast cancer cells in vivo, with a more substantial anticancer action achieved when these cells are embedded in a matrix. Plasma of mice that received the IL-12 MSC-containing neo-organoids showed increased levels of IL-12 and IFN-γ. Histopathologic analysis revealed less tumor cells in implants of 4T1 cells with IL-12 MSCs, and the presence of necrotic tumor islets and necrotic capillaries, suggesting antiangiogenesis. We also showed that the anticancer effect exerted by the IL-12 MSCs is immune mediated because it is absent in immunodeficient mice, is not due to systemic IL-12 delivery, and also occurs in a B16 melanoma model. This study therefore establishes the feasibility of using gene-enhanced MSCs in a cell-based neo-organoid approach for cancer treatment. [Cancer Res 2008;68(12):4810–8]
Early-Onset Lymphoma and Extensive Embryonic Apoptosis in Two Domain-Specific Fen1 Mice Mutants
Authors: Larsen Elisabeth , Kleppa Liv , Meza Trine J. , Meza-Zepeda Leonardo A. , Rada Christina , Castellanos Cesilie G. , Lien Guro F. , Nesse Gaute J. , Neuberger Michael S. , Laerdahl Jon K. , William Doughty Richard , Klungland Arne
Published: June 2008

Flap endonuclease 1 (FEN1) processes Okazaki fragments in lagging strand DNA synthesis, and FEN1 is involved in several DNA repair pathways. The interaction of FEN1 with the proliferating cell nuclear antigen (PCNA) processivity factor is central to the function of FEN1 in both DNA replication and repair. Here we present two gene-targeted mice with mutations in FEN1. The first mutant mouse carries a single amino acid point mutation in the active site of the nuclease domain of FEN1 (Fen1E160D/E160D), and the second mutant mouse contains two amino acid substitutions in the highly conserved PCNA interaction domain of FEN1 (Fen1ΔPCNA/ΔPCNA). Fen1E160D/E160D mice develop a considerably elevated incidence of B-cell lymphomas beginning at 6 months of age, particularly in females. By 16 months of age, more than 90% of the Fen1E160D/E160D females have tumors, primarily lymphomas. By contrast, Fen1ΔPCNA/ΔPCNA mouse embryos show extensive apoptosis in the forebrain and vertebrae area and die around stage E9.5 to E11.5. [Cancer Res 2008;68(12):4571–8]
Activated Cholinergic Signaling Provides a Target in Squamous Cell Lung Carcinoma
Authors: Song Pingfang , Sekhon Harmanjatinder S. , Fu Xiao Wen , Maier Michelle , Jia Yibing , Duan Jie , Proskosil Becky J. , Gravett Courtney , Lindstrom Jon , Mark Gregory P. , Saha Saurabh , Spindel Eliot R.
Published: June 2008

The binding of exogenous nicotine to nicotinic acetylcholine (ACh) receptors (nAChR) and the binding of endogenous ACh to both nAChR and muscarinic ACh receptors (mAChR) stimulate growth of both small cell and non–small cell lung carcinomas. Understanding how cholinergic signaling is up-regulated in lung cancer may suggest new therapeutic approaches. Analysis of 28 squamous cell lung carcinomas (SCC) showed increased levels of α5 and β3 nAChR mRNA and increased levels of ACh associated with increased levels of choline acetyltransferase mRNA and decreased cholinesterase mRNAs. Lynx1, an allosteric inhibitor of nAChR activity, was also decreased in SCC. Thus, cholinergic signaling is broadly increased in SCC caused by increased levels of receptors, increased levels of ligands, and decreased levels of receptor inhibitors. Partially explaining the cholinergic up-regulation seen in SCC, incubation of the H520 SCC cell line with nicotine increased levels of ACh secretion, increased expression of nAChR, and, as measured by electrophysiologic recording, increased activity of the expressed nAChR. Consistent with these effects, nicotine stimulated proliferation of H520 cells. One approach to blocking proliferative effects of nicotine and ACh on growth of lung cancers may be through M3 mAChR antagonists, which can limit the activation of mitogen-activated protein kinase that is caused by both nicotinic and muscarinic signaling. This was tested with the M3-selective muscarinic antagonist darifenacin. Darifenacin blocked nicotine-stimulated H520 growth in vitro and also blocked H520 growth in nude mice in vivo. Thus, cholinergic signaling is broadly up-regulated in SCC and blocking cholinergic signaling can limit basal and nicotine-stimulated growth of SCC. [Cancer Res 2008;68(12):4693–700]
Oncolytic Vesicular Stomatitis Viruses Are Potent Agents for Intravesical Treatment of High-Risk Bladder Cancer
Authors: Hadaschik Boris A. , Zhang Kaixin , So Alan I. , Fazli Ladan , Jia William , Bell John C. , Gleave Martin E. , Rennie Paul S.
Published: June 2008

Bladder cancer is the second most common genitourinary malignancy. At initial diagnosis, ∼70% of cases are non–muscle-invasive; however, current treatment options for superficial disease are of limited efficacy because many patients will develop recurrent tumors. The purpose of this study was to examine two replication-competent oncolytic vesicular stomatitis virus (VSV) strains as intravesical agents in an orthotopic murine model of high-grade bladder cancer. Four human bladder cancer cell lines (RT4, MGH-U3, UM-UC3, and KU-7) were treated with either wild-type VSV or a mutant Δ51M variant (AV3) in vitro. Both wild-type VSV and AV3, which has an impaired ability to shutdown innate immunity, preferentially killed the more aggressive, IFN-nonresponsive cell lines UM-UC3 and KU-7, whereas IFN-responsive RT4 and MGH-U3 cells were less susceptible. In vivo, KU-7-luc bladder tumor cells, which stably express firefly luciferase, were inoculated into nude mice by intravesical instillation and tumor growth was quantified using bioluminescence imaging. Mice with established xenografts were administered VSV intravesically on days 4, 9, and 14, and necropsy was performed after 3 weeks. AV3 as well as wild-type VSV significantly inhibited KU-7-luc tumor growth by 90% (AV3) and 98% (wild-type), respectively, as compared with controls treated with UV-inactivated VSV. Despite using immunocompromised hosts, there was no evidence of toxicity in either group. In conclusion, VSV instillation therapy showed promising antitumor activity and safety in an orthotopic model of bladder cancer. These findings provide preclinical proof-of-principle for the intravesical use of VSV against non–muscle-invasive bladder cancer, especially in IFN-refractory patients. [Cancer Res 2008;68(12):4506–10]
Genome-Wide Analysis of Aromatase Inhibitor-Resistant, Tamoxifen-Resistant, and Long-Term Estrogen-Deprived Cells Reveals a Role for Estrogen Receptor
Authors: Masri Selma , Phung Sheryl , Wang Xin , Wu Xiwei , Yuan Yate-Ching , Wagman Lawrence , Chen Shiuan
Published: June 2008

Acquired resistance to either tamoxifen or aromatase inhibitors (AI) develops after prolonged treatment in a majority of hormone-responsive breast cancers. In an attempt to further elucidate mechanisms of acquired resistance to AIs, MCF-7aro cells resistant to letrozole (T+LET R), anastrozole (T+ANA R), and exemestane (T+EXE R), as well as long-term estrogen deprived (LTEDaro) and tamoxifen-resistant (T+TAM R) lines were generated. This is the first complete panel of endocrine therapy–resistant cell lines, which were generated as multiple independent biological replicates for unbiased genome-wide analysis using affymetrix microarrays. Although similarities are apparent, microarray results clearly show gene signatures unique to AI-resistance were inherently different from LTEDaro and T+TAM R gene expression profiles. Based on hierarchical clustering, unique estrogen-responsive gene signatures vary depending on cell line, with some genes up-regulated in all lines versus other genes up-regulated only in the AI-resistant lines. Characterization of these resistant lines showed that LTEDaro, T+LET R, and T+ANA R cells contained a constitutively active estrogen receptor (ER)α that does not require estrogen for activation. This ligand-independent activation of ER was not observed in the parental cells, as well as T+EXE R and T+TAM R cells. Further characterization of these resistant lines was performed using cell cycle analysis, immunofluorescence experiments to visualize ER subcellular localization, as well as cross-resistance studies to determine second-line inhibitor response. Using this well-defined model system, our studies provide important information regarding differences in resistance mechanisms to AIs, TAM, and LTEDaro, which are critical in overcoming resistance when treating hormone-responsive breast cancers. [Cancer Res 2008;68(12):4910–8]
Gain of Oncogenic Function of p53 Mutants Induces Invasive Phenotypes in Human Breast Cancer Cells by Silencing CCN5/WISP-2
Authors: Dhar Gopal , Banerjee Snigdha , Dhar Kakali , Tawfik Ossama , Mayo Matthew S. , VanVeldhuizen Peter J. , Banerjee Sushanta K.
Published: June 2008

CCN5/WISP-2 is overexpressed in noninvasive breast cancer cells and tissue samples, whereas its expression is minimal or undetected in invasive conditions. CCN5/WISP-2 has been considered as an antiinvasive gene because CCN5/WISP-2 silencing augments the invasive phenotypes in vitro. However, the mechanism of silencing of CCN5 during the progression of the disease has been elusive. Because p53 mutations are associated with breast cancer progression and have been shown to correlate inversely with CCN5/WISP-2 expression in other cancer cell types, the objective of this study was to explore whether p53 mutants suppress CCN5 expression in breast tumor cells resulting in the progression of this disease. We found CCN5 expression is inversely correlated with the mutational activation of p53 in human breast tumor cells. The ectopic expression of p53 mutants in ER-positive noninvasive breast tumor cells silenced the CCN5/WISP-2 expression and enhanced invasive phenotypes, including the induction of morphologic changes from the epithelial-to-mesenchymal type along with the alterations of hallmark proteins of these cell types and an augmentation of the migration of these cells. The suppression of CCN5 by the p53 mutants can be nullified by estrogen signaling in these cells through the transcriptional activation of the CCN5 gene. Moreover, the invasive changes can be imitated by blocking the CCN5/WISP-2 expression through RNA interference or can be reversed by the addition of CCN5/WISP-2 recombinant protein in the culture. Thus, these studies suggest that CCN5 inactivation could be an essential molecular event for p53 mutant–induced invasive phenotypes. [Cancer Res 2008;68(12):4580–7]
The Chemokine Receptor CXCR6 and Its Ligand CXCL16 Are Expressed in Carcinomas and Inhibit Proliferation
Authors: Meijer Joost , Ogink Janneke , Kreike Bas , Nuyten Dimitry , de Visser Karin E. , Roos Ed
Published: June 2008

The chemokine receptor CXCR6 and its ligand CXCL16 are involved in inflammation. Thus far, they were known to be expressed mainly by T cells and macrophages, respectively. However, we detected both in all of 170 human primary mammary carcinomas and at similar levels in all 8 human mammary carcinoma cell lines tested by microarray analysis. Expression was confirmed by reverse transcription-PCR and for the cell lines also by fluorescence-activated cell sorting analysis. CXCR6 and CXCL16 were also detected in several mouse and human mammary, colon, and pancreatic carcinoma cell lines. CXCL16 is a transmembrane protein from which the soluble chemokine can be cleaved off. The transmembrane form is present on the surface of the carcinoma cells. Surprisingly, suppression of either CXCR6 or CXCL16 led to greatly enhanced proliferation in vitro as well as in vivo, indicating that their interaction inhibits proliferation. This notion was verified using inhibitory antibodies and by introduction of CXCL16 into a rare CXCL16-negative cell line. The effect was mediated by the G protein–coupled receptor CXCR6 because it was blocked by the Gi protein inhibitor pertussis toxin. In contrast, the soluble CXCL16 chemokine enhanced proliferation, and this was also mediated by CXCR6 but not via Gi protein. It is remarkable that both CXCR6 and CXCL16 are expressed by all mammary carcinomas because cells that lose either acquire a growth advantage and should be selected during tumor progression. This suggests an unknown important role in tumor formation. Proteases, possibly macrophage derived, might convert inhibitory transmembrane CXCL16 into the stimulatory chemokine. [Cancer Res 2008;68(12):4701–8]
Salmonella Promoters Preferentially Activated Inside Tumors
Authors: Arrach Nabil , Zhao Ming , Porwollik Steffen , Hoffman Robert M. , McClelland Michael
Published: June 2008

Salmonella enterica and avirulent derivatives prefer solid tumors over normal tissue in animal models. The identification of endogenous Salmonella promoters that are preferentially activated in tumors could further our understanding of this phenomenon. Toward this goal, a random library of S. enterica typhimurium 14028 genomic DNA was cloned upstream of a promoterless gene encoding the green fluorescent protein (GFP) TurboGFP. A population of Salmonella containing this library was injected i.v. into tumor-free nude mice and into human PC3 prostate tumors growing subcutaneously in nude mice. After 2 days, fluorescence-activated cell sorting was used to enrich for bacterial clones expressing GFP from spleens or tumors. The resulting libraries were hybridized to an oligonucleotide tiling array of the Salmonella genome. Eighty-six intergenic regions were found to be enriched in tumor samples but not in spleen. Twenty of these candidate promoters were also detected in the sequences of 100 random clones from a library enriched for expression in bacteria growing in tumors. Three candidate promoter clones were individually tested in vivo, and enhanced GFP expression in bacteria growing in tumor relative to spleen was confirmed. Two of the three clones (pflE and ansB promoter regions) are known to be induced in hypoxic conditions that pertain to many tumors. For many of the other candidate promoters preferentially induced in bacteria growing in tumors, regulatory mechanisms may not be related to hypoxia. The expression of therapeutics in Salmonella under the regulation of one or more promoters that are activated preferentially in tumors has the potential to improve the targeting of drug delivery. [Cancer Res 2008;68(12):4827–32]
Role of Acetylation and Extracellular Location of Heat Shock Protein 90α in Tumor Cell Invasion
Authors: Yang Yonghua , Rao Rehka , Shen Jie , Tang Yun , Fiskus Warren , Nechtman John , Atadja Peter , Bhalla Kapil
Published: June 2008

Heat shock protein (hsp) 90 is an ATP-dependent molecular chaperone that maintains the active conformation of client oncoproteins in cancer cells. An isoform, hsp90α, promotes extracellular maturation of matrix metalloproteinase (MMP)-2, involved in tumor invasion and metastasis. Knockdown of histone deacetylase (HDAC) 6, which deacetylates lysine residues in hsp90, induces reversible hyperacetylation and attenuates ATP binding and chaperone function of hsp90. Here, using mass spectrometry, we identified seven lysine residues in hsp90α that are hyperacetylated after treatment of eukaryotic cells with a pan-HDAC inhibitor that also inhibits HDAC6. Depending on the specific lysine residue in the middle domain involved, although acetylation affects ATP, cochaperone, and client protein binding to hsp90α, acetylation of all seven lysines increased the binding of hsp90α to 17-allyl-amino-demethoxy geldanamycin. Notably, after treatment with the pan-HDAC inhibitor panobinostat (LBH589), the extracellular hsp90α was hyperacetylated and it bound to MMP-2, which was associated with increased in vitro tumor cell invasiveness. Treatment with antiacetylated hsp90α antibody inhibited in vitro invasion by tumor cells. Thus, reversible hyperacetylation modulates the intracellular and extracellular chaperone function of hsp90, and targeting extracellular hyperacetylated hsp90α may undermine tumor invasion and metastasis. [Cancer Res 2008;68(12):4833–42]
Cisplatin Induces p53-Dependent FLICE-Like Inhibitory Protein Ubiquitination in Ovarian Cancer Cells
Authors: Abedini Mohammad R. , Muller Emilie J. , Brun Jan , Bergeron Richard , Gray Douglas A. , Tsang Benjamin K.
Published: June 2008

Understanding the mechanism of cisplatin (CDDP) action may improve therapeutic strategy for ovarian cancer. Although p53 and FLICE-like inhibitory protein (FLIP) are determinants of CDDP sensitivity in ovarian cancer, the interaction between p53 and FLIP remains poorly understood. Here, using two chemosensitive ovarian cancer cell lines and various molecular and cellular approaches, we show that CDDP induces p53-dependent FLIP ubiquitination and degradation, and apoptosis in vitro. Moreover, we showed that Itch (an E3 ligase) forms a complex with FLIP and p53 upon CDDP treatment. These results suggest that p53 facilitates FLIP down-regulation by CDDP-induced FLIP ubiquitination and proteasomal degradation. [Cancer Res 2008;68(12):4511–7]
Caspase-8: Fly or Die
Authors: Frisch Steven M.
Published: June 2008

Recent studies have revealed that procaspase-8 has an important function in cell adhesion and motility. Src phosphorylation controls this function by preventing the conversion of procaspase-8, which is an adhesion/migration factor, to mature caspase-8, which is an apoptosis-inducing factor. This provides a mechanism to switch these opposing functions. In its migratory role, procaspase-8 interacts with the phosphatidylinositol-3-OH kinase regulatory subunit p85α and c-src to modulate signaling by Rac and extracellular signal-regulated kinase, and promote calpain activation. Here, I survey the findings of these studies and discuss potential mechanisms and ramifications for cancer prognosis and therapy. [Cancer Res 2008;68(12):4491–3]
ArgBP2-Dependent Signaling Regulates Pancreatic Cell Migration, Adhesion, and Tumorigenicity
Authors: Taieb David , Roignot Julie , André Frédéric , Garcia Stéphane , Masson Bénédicte , Pierres Anne , Iovanna Juan-Lucio , Soubeyran Philippe
Published: June 2008

The poor prognosis of pancreatic cancer is due to rapid locoregional invasion, the early development of metastases, and the limited efficacy of current therapies. To date, none of the identified oncogenes and suppressors involved in this disease have led to efficient treatments. Here, we describe that the scaffold protein ArgBP2 is repressed during oncogenic transformation of the pancreas. We could show, using a pancreatic cancer cell line model, that this repression of ArgBP2 participates in the progression of this disease. Interestingly, in vitro analyses revealed that the antitumoral potential of ArgBP2 is linked to the control of cell adhesion and migration rather than to the regulation of cell proliferation or sensitivity to apoptosis. Moreover, we could detail part of the molecular mechanism responsible by identifying new ArgBP2-interacting proteins, and show that this function is partly achieved by the control of a WAVE/PTP-PEST/c-Abl signaling complex. These findings point to a new mechanism of pancreatic cancer progression leading to invasion and metastasis and suggest that the ArgBP2 signaling pathway could represent a new target for cancer therapy. [Cancer Res 2008;68(12):4588–96]
Overexpression of CDC25B and LAMC2 mRNA and Protein in Esophageal Squamous Cell Carcinomas and Premalignant Lesions in Subjects from a High-Risk Population in China
Authors: Shou Jian-Zhong , Hu Nan , Takikita Mikiko , Roth Mark J. , Johnson Laura Lee , Giffen Carol , Wang Quan-Hong , Wang Chaoyu , Wang Yuan , Su Hua , Kong Li-Hui , Emmert-Buck Michael R. , Goldstein Alisa M. , Hewitt Stephen M. , Taylor Philip R.
Published: June 2008

Molecular events associated with the initiation and progression of esophageal squamous cell carcinoma (ESCC) remain poorly understood but likely hold the key to effective early detection approaches for this almost invariably fatal cancer. CDC25B and LAMC2 are two promising early detection candidates emerging from new molecular studies of ESCC. To further elucidate the role of these two genes in esophageal carcinogenesis, we did a series of studies to (a) confirm RNA overexpression, (b) establish the prevalence of protein overexpression, (c) relate protein overexpression to survival, and (d) explore their potential as early detection biomarkers. Results of these studies indicated that CDC25B mRNA was overexpressed (≥2-fold overexpression in tumor compared with normal) in 64% of the 73 ESCC cases evaluated, whereas LAMC2 mRNA was overexpressed in 89% of cases. CDC25B protein expression was categorized as positive in 59% (144 of 243) of ESCC cases on a tumor tissue microarray, and nonnegative LAMC2 patterns of protein expression were observed in 82% (225 of 275) of cases. Multivariate-adjusted proportional hazard regression models showed no association between CDC25B protein expression score and risk of death [hazard ratio (HR) for each unit increase in expression score, 1.00; P = 0.90]; however, several of the LAMC2 protein expression patterns strongly predicted survival. Using the cytoplasmic pattern as the reference (the pattern with the lowest mortality), cases with a diffuse pattern had a 254% increased risk of death (HR, 3.52; P = 0.007), cases with no LAMC2 expression had a 169% increased risk of death (HR, 2.69; P = 0.009), and cases with a peripheral pattern had a 130% greater risk of death (HR, 2.30; P = 0.02). CDC25B protein expression scores in subjects with esophageal biopsies diagnosed as normal (n = 35), dysplastic (n = 23), or ESCC (n = 32) increased significantly with morphologic progression. For LAMC2, all normal and dysplastic patients had a continuous pattern of protein expression, whereas all ESCCs showed alternative, noncontinuous patterns. This series of studies showed that both CDC25B and LAMC2 overexpress RNA and protein in a significant majority of ESCC cases. The strong relation of LAMC2 pattern of protein expression to survival suggests a role in prognosis, whereas the association of CDC25B with morphologic progression indicates a potential role as an early detection marker. (Cancer Epidemiol Biomarkers Prev 2008;17(6):1424–35)
Strong Association of Chromosome 1p12 Loci with Thyroid Cancer Susceptibility
Authors: Baida Aida , Akdi Mounaim , González-Flores Eddy , Galofré Pere , Marcos Ricard , Velázquez Antonia
Published: June 2008

Several genes directly related to thyroid cancer development have been described; nevertheless, the genetic pathways of this tumorigenesis process are unknown. Together with environmental factors, susceptibility genes could have an important role in thyroid cancer. Our previous studies suggest that the chromosome 1p12-13 is related to thyroid cancer incidence. Here, we extend the analysis with a case-control association study in a Spanish population. Thus, six single-nucleotide polymorphisms were genotyped, covering 2.4 Mb of the 1p12-13 region. A statistically significant association between thyroid cancer incidence and the rs2145418 and rs4658973 polymorphisms was found (P < 0.0001). No association was detected for the other four polymorphisms studied. The rs2145418 marker showed a significant odds ratio of 5.0 [95% confidence interval (95% CI), 2.85-8.83] and 9.2 (95% CI, 4.50-21.6) for heterozygous and homozygous G-variant alleles, respectively. For rs4658973, the odds ratios were 0.40 (95% CI, 0.26-0.62) and 0.07 (95% CI, 0.03-0.18) for heterozygous and homozygous G-variant alleles, respectively. These markers map into the 1p12 region, and no linkage disequilibrium was found between them, indicating an independent relation of these polymorphisms with thyroid cancer susceptibility. Our data provide evidence of a strong association of the chromosome 1p12 with thyroid cancer risk, and it is the first study describing susceptibility loci for thyroid cancer in this region. (Cancer Epidemiol Biomarkers Prev 2008;17(6):1499–504)
Light Exposure at Night, Urinary 6-Sulfatoxymelatonin, and Serum Estrogens and Androgens in Postmenopausal Japanese Women
Authors: Nagata Chisato , Nagao Yasuko , Yamamoto Satoru , Shibuya Chiken , Kashiki Yoshitomo , Shimizu Hiroyuki
Published: June 2008

It has been hypothesized that exposure to light at night increases the risk of breast cancer by suppressing the normal nocturnal increase in melatonin production and release, thereby resulting in increased levels of circulating estrogen. We assessed associations among concentrations of serum estrogen and androgen and the principal metabolite of melatonin in urine, 6-sulfatoxymelatonin, and exposure to light at night based on information regarding the sleeping habits and history of graveyard-shift work of 206 postmenopausal Japanese women. Serum estradiol level was significantly higher in women who were not asleep at or after 1:00 a.m. (the approximate time of the melatonin peak) than those who were asleep after controlling for covariates. Significantly increased estrone levels were observed in women who had worked graveyard shift. Serum testosterone and DHEA sulfate were unrelated to sleeping habits and history of graveyard-shift work. Urinary 6-sulfatoxymelatonin was lower in women who were not asleep at or after 1:00 a.m. on weekends than those who were asleep at this time, but the difference was of borderline significance (P = 0.08). There was no significant association between urinary 6-sulfatoxymelatonin and any serum hormone levels. These data suggest that exposure to light at night has implications for the risk of breast cancer in postmenopausal women. However, the potential role of melatonin as an intervening factor between light exposure at night and the serum concentrations of estrogen was equivocal. (Cancer Epidemiol Biomarkers Prev 2008;17(6):1418–23)
Dietary Flavonoids and Colorectal Adenoma Recurrence in the Polyp Prevention Trial
Authors: Bobe Gerd , Sansbury Leah B. , Albert Paul S. , Cross Amanda J. , Kahle Lisa , Ashby Jason , Slattery Martha L. , Caan Bette , Paskett Electra , Iber Frank , Kikendall James Walter , Lance Peter , Daston Cassandra , Marshall James R. , Schatzkin Arthur , Lanza Elaine
Published: June 2008

Two recent case-control studies suggested that some flavonoid subgroups may play a role in preventing colorectal cancer. Previous prospective cohort studies generally reported no association; however, only a small subset of flavonoids was evaluated and partial flavonoid databases were used. We used the newly constructed U.S. Department of Agriculture flavonoid database to examine the association between consumption of total flavonoids, 6 flavonoid subgroups, and 29 individual flavonoids with adenomatous polyp recurrence in the Polyp Prevention Trial. The Polyp Prevention Trial was a randomized dietary intervention trial, which examined the effectiveness of a low-fat, high-fiber, high-fruit, and high-vegetable diet on adenoma recurrence. Intakes of flavonoids were estimated from a food frequency questionnaire. Multivariate logistic regression models (adjusted for age, body mass index, sex, regular non–steroidal anti-inflammatory use, and dietary fiber intake) were used to estimate odds ratios and 95% confidence intervals for both any and advanced adenoma recurrence within quartiles of energy-adjusted flavonoid intake (baseline, during the trial, and change during the trial). Total flavonoid intake was not associated with any or advanced adenoma recurrence. However, high intake of flavonols, which are at greater concentrations in beans, onions, apples, and tea, was associated with decreased risk of advanced adenoma recurrence (4th versus 1st quartile during the trial; odds ratio, 0.24; 95% confidence interval, 0.11, 0.53; Ptrend = 0.0006). Similar inverse associations were observed to a smaller extent for isoflavonoids, the flavonol kaempferol, and the isoflavonoids genistein and formononetin. Our data suggest that a flavonol-rich diet may decrease the risk of advanced adenoma recurrence. (Cancer Epidemiol Biomarkers Prev 2008;17(6):1344–53)
Comparing Genetic Ancestry and Self-Described Race in African Americans Born in the United States and in Africa
Authors: Yaeger Rona , Avila-Bront Alexa , Abdul Kazeem , Nolan Patricia C. , Grann Victor R. , Birchette Mark G. , Choudhry Shweta , Burchard Esteban G. , Beckman Kenneth B. , Gorroochurn Prakash , Ziv Elad , Consedine Nathan S. , Joe Andrew K.
Published: June 2008

Genetic association studies can be used to identify factors that may contribute to disparities in disease evident across different racial and ethnic populations. However, such studies may not account for potential confounding if study populations are genetically heterogeneous. Racial and ethnic classifications have been used as proxies for genetic relatedness. We investigated genetic admixture and developed a questionnaire to explore variables used in constructing racial identity in two cohorts: 50 African Americans and 40 Nigerians. Genetic ancestry was determined by genotyping 107 ancestry informative markers. Ancestry estimates calculated with maximum likelihood estimation were compared with population stratification detected with principal components analysis. Ancestry was approximately 95% west African, 4% European, and 1% Native American in the Nigerian cohort and 83% west African, 15% European, and 2% Native American in the African American cohort. Therefore, self-identification as African American agreed well with inferred west African ancestry. However, the cohorts differed significantly in mean percentage west African and European ancestries (P < 0.0001) and in the variance for individual ancestry (P ≤ 0.01). Among African Americans, no set of questionnaire items effectively estimated degree of west African ancestry, and self-report of a high degree of African ancestry in a three-generation family tree did not accurately predict degree of African ancestry. Our findings suggest that self-reported race and ancestry can predict ancestral clusters but do not reveal the extent of admixture. Genetic classifications of ancestry may provide a more objective and accurate method of defining homogenous populations for the investigation of specific population-disease associations. (Cancer Epidemiol Biomarkers Prev 2008;17(6):1329–38)
DNA Repair Capacity and Lung Cancer Risk in Never Smokers
Authors: Gorlova Olga Y. , Weng Shih-Feng , Zhang Yiqun , Amos Christopher I. , Spitz Margaret R. , Wei Qingyi
Published: June 2008

Besides secondhand smoke exposure, few other risk factors for lung cancer in lifetime never smokers have been identified. We present the estimates of lung cancer risk associated with suboptimal DNA repair capacity (DRC) measured by the host-cell reactivation assay in lifetime never smokers using data from 219 cases and 309 matched controls enrolled in a case-control study. Suboptimal DRC level (below the control median) conferred a significantly increased lung cancer risk in never smokers [odds ratio, 1.92; 95% confidence interval (95% CI), 1.3-2.9; P = 0.0024]. There was a 3.38-fold risk for individuals with DRC below the first quartile (95% CI, 1.8-6.3) compared with individuals with DRC above the third quartile. Secondhand smoke exposure in individuals with DRC below the control median was associated with a 3.81-fold risk of lung cancer (95% CI, 2.3-6.4). A 2.49-fold (95% CI, 1.1-5.6) risk was noted for the joint effects of lung cancer family history in first-degree relatives and suboptimal DRC. Relatives of probands (cases and controls) with lowest DRC (below the first quartile) were significantly more likely to be diagnosed with lung cancer (odds ratio, 2.69; 95% CI, 1.1-6.7) compared with relatives of probands with the most proficient DRC (above the third quartile). Relatives of probands with suboptimal (below the control median) versus proficient DRC also had an earlier age at diagnosis with lung cancer, although the only statistically significant difference was in female relatives (55.4 versus 67.7 years; P = 0.03). (Cancer Epidemiol Biomarkers Prev 2008;17(6):1322–8)
BAGE Hypomethylation, A New Epigenetic Biomarker for Colon Cancer Detection
Authors: Grunau Christoph , Brun Marie-Elisabeth , Rivals Isabelle , Selves Janick , Hindermann Winfried , Favre-Mercuret Magali , Granier Guillaume , De Sario Albertina
Published: June 2008

Early detection of colorectal cancer is a decisive step in the successful and complete cure of the disease. Epigenetic markers, in particular, those based on aberrant DNA methylation, can be used to diagnose cancer. B melanoma antigens (BAGE) are a family of genes and truncated genes located in the heterochromatic regions of several human chromosomes. Our previous work showed that BAGE loci (i.e., genes and truncated genes) were hypermethylated in normal tissues and hypomethylated in 98% of human cancers. In the present study, we analyzed DNA methylation of the BAGE loci in 54 colon cancers and in neighboring histopathologic normal tissue samples. Using a combined bisulfite restriction assay, we showed that BAGE loci were hypomethylated in 81% of carcinoma samples. Colon cancer could be diagnosed with 94% specificity, 83% sensitivity, and 89% accuracy. No correlation was found between DNA methylation of BAGE loci and age, gender of patients, nor with the tumor stage or site. Based on the hypothesis that during neoplastic transformation, hypomethylation occurs in juxtacentromeric CpG islands, we suggest that other genes located in the heterochromatic compartment should be tested. These new markers enrich the list of currently studied epigenetic alterations in colon cancer and could be associated with hypermethylation markers to develop reliable diagnostic tests. (Cancer Epidemiol Biomarkers Prev 2008;17(6):1374–9)