bluuebunny/crossref_metadata_2025_split huggingface dataset:
Murine Cell Lines Derived from Pten Null Prostate Cancer Show the Critical Role of PTEN in Hormone Refractory Prostate Cancer Development
Authors: Jiao Jing , Wang Shunyou , Qiao Rong , Vivanco Igor , Watson Philip A. , Sawyers Charles L. , Wu Hong 
Published: July 2007

Abstract
PTEN mutations are among the most frequent genetic alterations found in human prostate cancers. Our previous works suggest that although precancerous lesions were found in Pten heterozygous mice, cancer progression and metastasis only happened when both alleles of Pten were deleted. To understand the molecular mechanisms underlying the role of PTEN in prostate cancer control, we generated two pairs of isogenic, androgen receptor (AR)–positive prostate epithelial lines from intact conditional Pten knock-out mice that are either heterozygous (PTEN-P2 and -P8) or homozygous (PTEN-CaP2 and PTEN-CaP8) for Pten deletion. Further characterization of these cells showed that loss of the second allele of Pten leads to increased anchorage-independent growth in vitro and tumorigenesis in vivo without obvious structural or numerical chromosome changes based on SKY karyotyping analysis. Despite no prior exposure to hormone ablation therapy, Pten null cells are tumorigenic in both male and female severe combined immunodeficiency mice. Furthermore, knocking down PTEN can convert the androgen-dependent Myc-CaP cell into androgen independence, suggesting that PTEN intrinsically controls androgen responsiveness, a critical step in the development of hormone refractory prostate cancer. Importantly, knocking down AR by shRNA in Pten null cells reverses androgen-independent growth in vitro and partially inhibited tumorigenesis in vivo, indicating that PTEN-controlled prostate tumorigenesis is AR dependent. These cell lines will serve as useful tools for understanding signaling pathways controlled by PTEN and elucidating the molecular mechanisms involved in hormone refractory prostate cancer formation. [Cancer Res 2007;67(13):6083–91]
A 3′ Enhancer Controls Snail Expression in Melanoma Cells
Authors: Palmer Matthew B. , Majumder Parimal , Green Myesha R. , Wade Paul A. , Boss Jeremy M. 
Published: July 2007

Abstract
The snail gene encodes a transcriptional repressor that functions during animal development and in cancer progression to promote epithelial-mesenchymal transitions. Strict spatial and temporal boundaries of Snail expression in development imply precise transcriptional control, which becomes inappropriately activated in many cancer subtypes. To gain insight into the molecular mechanism(s) governing transcriptional control of Snail, we analyze chromatin structural changes associated with Snail transcription in melanoma cells. Regardless of transcriptional status, the Snail promoter displays three constitutive DNase hypersensitive sites (HS) and a moderate level of histone H3 Lys4 dimethylation. A robust HS is found in the 3′ region of A375 melanoma cells, in which Snail is highly expressed, but is absent in cells not expressing Snail. This element is conserved throughout the mammalian lineage and strongly activates expression of a reporter in A375 and Colo829 melanoma cells, but not in keratinocytes or primary melanocytes. Activity of this enhancer is associated with enrichment of H3 Lys4 dimethylation and H3 acetylation at both the enhancer and the promoter. Additionally, enhancer activity is associated with H3 Lys4 trimethylation at the promoter. A physical interaction between the 3′ enhancer and promoter was observed in Snail-expressing cells, demonstrating a direct role for the enhancer in Snail expression. These results suggest a model in which the Snail promoter is constitutively packaged in a poised chromatin structure that can be activated in melanoma cells by a tissue-specific enhancer, which physically contacts the promoter. [Cancer Res 2007;67(13):6113–20]
Elevated Frequencies of Self-reactive CD8+ T Cells following Immunization with a Xenoantigen Are Due to the Presence of a Heteroclitic CD4+ T-Cell Helper Epitope
Authors: Kianizad Korosh , Marshall Laura A. , Grinshtein Natalie , Bernard Dannie , Margl Renate , Cheng Sheng , Beermann Friedrich , Wan Yonghong , Bramson Jonathan 
Published: July 2007

Abstract
Immunization of mice with human dopachrome tautomerase (hDCT) provides greater protection against melanoma than immunization with the murine homologue (mDCT). We mapped the CD8+ and CD4+ T-cell epitopes in both proteins to better understand the mechanisms of the enhanced protection. The dominant CD8+ T-cell epitopes were fully conserved between both proteins, yet immunization with hDCT produced frequencies of CD8+ T cells that were 5- to 10-fold higher than immunization with mDCT. This difference was not intrinsic to the two proteins because comparable frequencies of CD8+ T cells were elicited by both antigens in DCT-deficient mice. Strikingly, only hDCT elicited a significant level of specific CD4+ T cells in wild-type (WT) mice. The murine protein was not devoid of CD4+ T-cell epitopes because immunization of DCT-deficient mice with mDCT resulted in robust CD4+ T-cell immunity directed against two epitopes that were not identified in WT mice. These results suggested that the reduced immunogenicity of mDCT in WT mice may be a function of insufficient CD4+ T-cell help. To address this possibility, the dominant CD4+ T-cell epitope from hDCT was introduced into mDCT. Immunization with the mutated mDCT evoked CD8+ T-cell frequencies and protective immunity comparable with hDCT. These results reveal a novel mechanism by which xenoantigens overcome tolerance. Our data also suggest that immunologic tolerance is more stringent for CD4+ T cells than CD8+ T cells, providing a mechanism of peripheral tolerance where autoreactive CD8+ T cells fail to be activated due to a lack of autoreactive CD4+ T cells specific for the same antigen. [Cancer Res 2007;67(13):6459–67]
Cyclin G1 Is a Target of miR-122a, a MicroRNA Frequently Down-regulated in Human Hepatocellular Carcinoma
Authors: Gramantieri Laura , Ferracin Manuela , Fornari Francesca , Veronese Angelo , Sabbioni Silvia , Liu Chang-Gong , Calin George A. , Giovannini Catia , Ferrazzi Eros , Grazi Gian Luca , Croce Carlo M. , Bolondi Luigi , Negrini Massimo 
Published: July 2007

Abstract
We investigated the role of microRNAs (miRNAs) in the pathogenesis of human hepatocellular carcinoma (HCC). A genome-wide miRNA microarray was used to identify differentially expressed miRNAs in HCCs arisen on cirrhotic livers. Thirty-five miRNAs were identified. Several of these miRNAs were previously found deregulated in other human cancers, such as members of the let-7 family, mir-221, and mir-145. In addition, the hepato-specific miR-122a was found down-regulated in ∼70% of HCCs and in all HCC-derived cell lines. Microarray data for let-7a, mir-221, and mir-122a were validated by Northern blot and real-time PCR analysis. Understanding the contribution of deregulated miRNAs to cancer requires the identification of gene targets. Here, we show that miR-122a can modulate cyclin G1 expression in HCC-derived cell lines and an inverse correlation between miR-122a and cyclin G1 expression exists in primary liver carcinomas. These results indicate that cyclin G1 is a target of miR-122a and expand our knowledge of the molecular alterations involved in HCC pathogenesis and of the role of miRNAs in human cancer. [Cancer Res 2007;67(13):6092–9]
FRA-1 Proto-Oncogene Induces Lung Epithelial Cell Invasion and Anchorage-Independent Growth In vitro, but Is Insufficient to Promote Tumor Growth In vivo
Authors: Adiseshaiah Pavan , Lindner Daniel J. , Kalvakolanu Dhananjaya V. , Reddy Sekhar P. 
Published: July 2007

Abstract
FRA-1 forms activator protein-1 complexes in association with members of the JUN family and drives gene transcription. FRA-1 has been implicated in the development of airway squamous metaplasia and is frequently overexpressed in squamous cell carcinomas of the esophagus and stomach. We and others have shown a high level of persistent induction of FRA-1 by lung carcinogens, such as cigarette smoke and asbestos, in pulmonary epithelial cells. However, the exact roles of FRA-1 in regulating lung epithelial cell growth and invasion are poorly understood. To examine this aspect, we have stably overexpressed FRA-1 in human type-II–like alveolar malignant cell line (A549) and a nonmalignant bronchial epithelial cell line (BEAS-2B). FRA-1 greatly enhanced the rate of proliferation, motility, and invasion of A549 and BEAS-2B cells. In athymic nude mice, FRA-1, but not the control vector, rapidly enhanced tumor formation and metastasis by A549 cells. In contrast, FRA-1 failed to promote tumor formation by BEAS-2B. We suggest that FRA-1 can promote motility, invasion, and anchorage-independent growth of lung epithelial cells in vitro, but is insufficient for tumor formation. [Cancer Res 2007;67(13):6204–11]
Tumor-Suppressive Activity of the Cell Death Activator GRIM-19 on a Constitutively Active Signal Transducer and Activator of Transcription 3
Authors: Kalakonda Sudhakar , Nallar Shreeram C. , Lindner Daniel J. , Hu Jiadi , Reddy Sekhar P. , Kalvakolanu Dhananjaya V. 
Published: July 2007

AbstractSignal transducers and activators of transcription 3 (STAT3) was originally identified as a transcription factor that mediates cytokine-induced responses. In these pathways, Janus-activated kinase (JAK)–induced transient tyrosine phosphorylation of STAT3 promotes gene expression in response to a number of cytokines, which is inhibited by feedback mechanisms. A number of studies have shown that STAT3 is constitutively activated in human cancer cells, leading to cell proliferation. It is unclear, apart from a chronic tyrosyl phosphorylation of STAT3, what mechanisms contribute to the STAT3 deregulation in tumors. Earlier, we have isolated a novel growth inhibitory gene product, gene associated with retinoid-IFN–induced mortality 19 (GRIM-19), using a genetic approach. GRIM-19 is an IFN/retinoic acid–regulated growth suppressor. Subsequent analyses have shown that GRIM-19 binds to STAT3 and prevents interleukin-6–induced transcription of cellular genes. However, its effects on a constitutively active STAT3 and cellular transformation are unknown. In this study, we show that GRIM-19 suppresses constitutive STAT3-induced cellular transformation in vitro and in vivo by down-regulating the expression of a number of cellular genes involved in cell proliferation and apoptosis. [Cancer Res 2007;67(13):6212–20]
The Role of Protein Binding in Induction of Apoptosis by Phenethyl Isothiocyanate and Sulforaphane in Human Non–Small Lung Cancer Cells
Authors: Mi Lixin , Wang Xiantao , Govind Sudha , Hood Brian L. , Veenstra Timothy D. , Conrads Thomas P. , Saha Daniel T. , Goldman Radoslav , Chung Fung-Lung 
Published: July 2007

Abstract
Induction of apoptosis underlies a mechanism for inhibiting tumorigenesis by phenethyl isothiocyanate (PEITC) and sulforaphane (SFN). However, the upstream events by which isothiocyanates (ITC) induce apoptosis have not been fully investigated. As electrophiles, ITCs could trigger apoptosis by binding to DNA or proteins or by inducing oxidative stress. To better understand the molecular mechanisms of apoptosis by ITCs, we examined, as a first step, the role of these events in human non–small lung cancer A549 cells. PEITC was a more potent inducer than SFN; it induced apoptosis at 20 μmol/L, whereas SFN induced at 40 μmol/L but not at 20 μmol/L. To study binding with cellular proteins and DNA, cells were treated with 14C-ITCs; the initial protein binding by PEITC was almost 3-fold than that of SFN. The binding by PEITC increased with time, whereas binding by SFN remained low. Therefore, 4 h after incubation proteins became the predominant targets for PEITC with a 6-fold binding than that of SFN. To characterize the chemical nature of binding by the ITCs, we used bovine serum albumin (BSA) as a surrogate protein. PEITC also modified BSA covalently to a greater extent than SFN occurring exclusively at cysteine residues. Surprisingly, neither PEITC nor SFN bound to DNA or RNA at detectable levels or caused significant DNA strand breakage. The levels of oxidative damage in cells, measured as reactive oxygen species, 8-oxo-deoxyguanosine, and protein carbonyls formation, were greater in cells treated with SFN than PEITC. Because PEITC is a stronger inducer of apoptosis than SFN, these results indicate that direct covalent binding to cellular proteins is an important early event in the induction of apoptosis by the ITCs. [Cancer Res 2007;67(13):6409–16]
Phosphorylation of ATR-Interacting Protein on Ser239 Mediates an Interaction with Breast-Ovarian Cancer Susceptibility 1 and Checkpoint Function
Authors: Venere Monica , Snyder Andrew , Zgheib Omar , Halazonetis Thanos D. 
Published: July 2007

Abstract
The signaling of DNA damage and replication stress involves a multitude of proteins, including the kinases ataxia-telangiectasia mutated (ATM) and ATM and Rad3-related (ATR), and proteins with BRCA1 COOH-terminal (BRCT) domains. The BRCT domain–containing proteins facilitate the phosphorylation of ATM/ATR substrates and can be coimmunoprecipitated with ATM or ATR. However, their mode of interaction with the ATM/ATR kinases remains elusive. Here, we show that breast-ovarian cancer susceptibility 1 (BRCA1) interacts directly with ATR-interacting protein (ATRIP), an obligate partner of ATR. The interaction involves the BRCT domains of BRCA1 and Ser239 of ATRIP, a residue that is phosphorylated in both irradiated and nonirradiated cells. Consistent with a role of BRCA1 in ATR signaling, substitution of Ser239 of ATRIP with Ala leads to a G2-M checkpoint defect. We propose that a direct physical interaction between BRCA1 and ATRIP is required for the checkpoint function of ATR. [Cancer Res 2007;67(13):6100–5]
Increased Susceptibility to Colitis-Associated Cancer of Mice Lacking TIR8, an Inhibitory Member of the Interleukin-1 Receptor Family
Authors: Garlanda Cecilia , Riva Federica , Veliz Tania , Polentarutti Nadia , Pasqualini Fabio , Radaelli Enrico , Sironi Marina , Nebuloni Manuela , Zorini Elisabetta Omodeo , Scanziani Eugenio , Mantovani Alberto 
Published: July 2007

Abstract
TIR8 (also known as SIGIRR) is a member of the interleukin-1/Toll-like receptor family with inhibitory activity on inflammatory reactions and high expression in intestinal mucosa. Here, we report that Tir8-deficient mice exhibited a dramatic intestinal inflammation in response to dextran sulfate sodium salt (DSS) administration in terms of weight loss, intestinal bleeding, and mortality and showed increased susceptibility to carcinogenesis in response to azoxymethane and DSS. Increased susceptibility to colitis-associated cancer was associated to increased permeability and local production of prostaglandin E2, proinflammatory cytokines, and chemokines. Thus, these results are consistent with the hypothesis that TIR8, by negatively regulating intestinal inflammation, plays a nonredundant role in the control of the protumor activity of chronic inflammation in the gut. [Cancer Res 2007;67(13):6017–21]
Alterations of the HBP1 Transcriptional Repressor Are Associated with Invasive Breast Cancer
Authors: Paulson K. Eric , Rieger-Christ Kimberly , McDevitt Michael A. , Kuperwasser Charlotte , Kim Jiyoung , Unanue Vincent E. , Zhang Xiaowei , Hu Maowen , Ruthazer Robin , Berasi Stephen P. , Huang Chun-Yin , Giri Dilip , Kaufman Seth , Dugan John M. , Blum Joanne , Netto Georges , Wazer David E. , Summerhayes Ian C. , Yee Amy S. 
Published: July 2007

Abstract
Invasive breast cancer has a high risk of recurrence to incurable disease and needs improved prognostic and therapeutic tools. Our work combines clinical and molecular analyses to show that the transcriptional repressor HBP1 may be a new target for invasive breast cancer. Previous work indicated that HBP1 regulated proliferation and senescence and inhibited Wnt signaling. Two of these functions have been associated with invasive breast cancer. In 76 breast tumors, we identified 10 HBP1 mutations/variants that were associated with fully invasive breast cancer. In a separate analysis, we found that a subset of invasive breast cancer specimens also had reduced HBP1 mRNA levels. These clinical correlations suggested that mutation or reduction of HBP1 occurs in invasive breast cancer and that HBP1 might regulate the proliferation and invasiveness of this breast cancer type. Analysis of the HBP1 mutants showed they were functionally defective for suppressing Wnt signaling. To test the consequences of reduced HBP1 levels, we used RNA interference to knock down HBP1 and observed increased Wnt signaling, tumorigenic proliferation, and invasiveness in cell and animal breast cancer models. Lastly, statistical analysis of a breast cancer patient database linked reduced HBP1 expression to breast cancer recurrence. In considering two-gene criteria for relapse potential, reduced expression of HBP1 and SFRP1, which is another Wnt inhibitor that was recently linked to invasive breast cancer, strikingly correlated with recurrence. Together, these data indicate that HBP1 may be a molecularly and clinically relevant regulator of breast cancer transitions that eventually lead to poor prognosis. [Cancer Res 2007;67(13):6136–45]
Induction of Postsurgical Tumor Immunity and T-Cell Memory by a Poorly Immunogenic Tumor
Authors: Zhang Peisheng , Côté Anik L. , de Vries Victor C. , Usherwood Edward J. , Turk Mary Jo 
Published: July 2007

AbstractThe generation of protective CD8 T-cell memory against tumor-expressed self-antigens is an important but elusive goal of cancer immunotherapy. The possibility that a progressive, poorly immunogenic tumor can induce T-cell memory against self-antigens has not previously been studied. Herein, we report that growth of the poorly immunogenic B16 melanoma in the absence of regulatory T cells (Treg) generates CD8 T-cell responses that develop into functional memory after the tumor has been surgically excised. Tumor-primed memory T cells recognized melanocyte differentiation antigens TRP-2/DCT and gp100 and persisted for as long as 5 months following surgical tumor excision. Phenotypic analysis showed that these cells develop into both central and effector memory T-cell subsets, which produce IFN-γ and interleukin-2 on reencounter with antigen. Most importantly, tumor-primed memory T cells mediated the rejection of intradermal and systemically disseminated challenge tumors given 30 to 60 days following surgery. Tumor-excised mice also developed autoimmune vitiligo, showing that Treg cells prevent tissue-specific autoimmunity in tumor-bearing hosts. This study establishes that Treg depletion in tumor-bearing hosts drives the natural development of protective T-cell memory. Generating such responses may aid in the clinical management of tumor recurrence and metastasis following surgery. [Cancer Res 2007;67(13):6468–76]
RING Domain–Mediated Interaction Is a Requirement for MDM2's E3 Ligase Activity
Authors: Kawai Hidehiko , Lopez-Pajares Vanessa , Kim Mihee M. , Wiederschain Dmitri , Yuan Zhi-Min 
Published: July 2007

Abstract
The RING domain of MDM2 that is essential for its E3 ligase activity mediates binding to itself and its structural homologue MDMX. Whereas it has been reported that RING domain interactions are critical, it is not well understood how they affect the E3 ligase activity of MDM2. We report that the E3 ligase activity requires the RING domain–dependent complex formation. In vivo, MDM2 and MDMX hetero-RING complexes are the predominant form versus the MDM2 homo-RING complex. Importantly, the MDM2/MDMX hetero-RING complexes exhibit a greater E3 ligase activity than the MDM2 homo-RING complexes. Disruption of the binding between MDM2 and MDMX resulted in a marked increase in both abundance and activity of p53, emphasizing the functional importance of this heterocomplex in p53 control. [Cancer Res 2007;67(13):6026–30]
Evaluation of antibodies to oxidized low-density lipoprotein and assessment of C-reactive protein in acute coronary syndrome and stable coronary artery disease
Authors: Soltesz Pal , Veres Katalin , Laczik Renata , Der Henrietta , Csipo Istvan , Timar Orsolya , Szomjak Edit , Szegedi Gyula , Szodoray Peter 
Published: July 2007

SummaryThe aim was to measure the level of antibodies to oxidized LDL (oxLDL) and C-reactive protein (CRP) in the serum of patients with acute coronary syndrome (ACS). The results were correlated with data obtained from patients with stable coronary artery disease (stable CAD) and healthy controls.Thirty-three patients with ACS and 62 stable CAD patients were enrolled in the study. Fifty healthy individuals served as controls.The evaluation of anti-oxLDL autoantibodies was performed by ELISA, while CRP levels were measured by turbidimetry. The level of antibodies to oxLDL was significantly higher in both groups of patients with ACS and stable CAD compared to controls.The comparison between the acute and stable groups showed that anti-oxLDL levels were higher in the acute group,but because of high SD, the difference was not significant. By performing group analysis, anti-oxLDL levels were found to be significantly higher in ACS patients with unstable clinical state (circulatory insufficiency, malignant arrhythmias, recurring ischemic pain, need for urgent coronary intervention and death). CRP level in patients with ACS was significantly higher than in those with stable CAD. A positive correlation was found between anti-oxLDL antibodies and CRP levels both in patients with ACS and stable CAD. The association between the two biomarkers was stronger in the ACS group. In conclusion, our findings support the notion that the presence of antibodies to oxLDL, a plaquespecific antigen, plays a major role as a predictor of complicated manifestations of ACS.
Prothrombotic markers and early spontaneous recanalization in ST-segment elevation myocardial infarction
Authors: Lanoy Emilie , Tcheche Didier , Feldman Laurent , Bezeaud Annie , Anglès-Cano Eduardo , Mary-Krause Murielle , de Prost Dominique , Guillin Marie-Claude , Steg Gabriel , Huisse Marie-Geneviève 
Published: July 2007

SummaryWe tested the hypothesis that selected prothrombotic biomarkers might be associated with early spontaneous coronary recanalization in patients with ST-segment elevation acute myocardial infarction (STEMI). We prospectively enrolled 123 patients with STEMI including 53 patients with spontaneous coronary recanalization (cases) and 70 patients with persistent occlusion (controls) at the time of emergent coronary angiography and before angioplasty. All had received aspirin and heparin. Blood samples were collected immediately before angioplasty to measure soluble P-selectin, circulating microparticles originating from platelets (PMPs), granulocytes (GMPs), endothelial cells (EMPs); tissue factor-associated MP (TF-MP); soluble platelet glycoprotein V (sGPV) and prothrombin F1+2; tissue plasminogen activator (tPA), plasminogen activator inhibitor (PAI-1) and plasmin-antiplasmin (PAP). A sub-group of 70 patients (35 cases, 35 controls) was available for flow cytometry analysis of platelet P-selectin and activated GPIIb-IIIa. Baseline clinical characteristics did not differ between groups except for more frequent hypertension and dyslipidemia in controls. Platelet activation markers and PMP did not differ between the two groups. Controls had higher numbers of EMPs and GMPs compared to cases, but the difference was no longer significant when corrected for risk factors. Controls differed from cases by higher plasma levels of sGPV [64 (47–84) ng/ml vs. 53 (44–63) ng/ml] and PAP [114(65–225) ng/ml vs. 88 (51–147) ng/ml].The difference persisted after adjustment for risks factors (p=0.031 and 0.037, respectively). Persistent occlusion of the infarct related artery is associated with some markers related to higher thrombin (sGPV) and plasmin (PAP) production but is not associated with markers of platelet activation.