bluuebunny/crossref_metadata_2025 huggingface dataset:
Estrogen Receptors: How Do They Signal and What Are Their Targets
Authors: Heldring Nina , Pike Ashley , Andersson Sandra , Matthews Jason , Cheng Guojun , Hartman Johan , Tujague Michel , Ström Anders , Treuter Eckardt , Warner Margaret , Gustafsson Jan-Åke
Published: July 2007

During the past decade there has been a substantial advance in our understanding of estrogen signaling both from a clinical as well as a preclinical perspective. Estrogen signaling is a balance between two opposing forces in the form of two distinct receptors (ERα and ERβ) and their splice variants. The prospect that these two pathways can be selectively stimulated or inhibited with subtype-selective drugs constitutes new and promising therapeutic opportunities in clinical areas as diverse as hormone replacement, autoimmune diseases, prostate and breast cancer, and depression. Molecular biological, biochemical, and structural studies have generated information which is invaluable for the development of more selective and effective ER ligands. We have also become aware that ERs do not function by themselves but require a number of coregulatory proteins whose cell-specific expression explains some of the distinct cellular actions of estrogen. Estrogen is an important morphogen, and many of its proliferative effects on the epithelial compartment of glands are mediated by growth factors secreted from the stromal compartment. Thus understanding the cross-talk between growth factor and estrogen signaling is essential for understanding both normal and malignant growth. In this review we focus on several of the interesting recent discoveries concerning estrogen receptors, on estrogen as a morphogen, and on the molecular mechanisms of anti-estrogen signaling.
Noncoding RNAs and RNA Editing in Brain Development, Functional Diversification, and Neurological Disease
Authors: Mehler Mark F. , Mattick John S.
Published: July 2007

The progressive maturation and functional plasticity of the nervous system in health and disease involve a dynamic interplay between the transcriptome and the environment. There is a growing awareness that the previously unexplored molecular and functional interface mediating these complex gene-environmental interactions, particularly in brain, may encompass a sophisticated RNA regulatory network involving the twin processes of RNA editing and multifaceted actions of numerous subclasses of non-protein-coding RNAs. The mature nervous system encompasses a wide range of cell types and interconnections. Long-term changes in the strength of synaptic connections are thought to underlie memory retrieval, formation, stabilization, and effector functions. The evolving nervous system involves numerous developmental transitions, such as neurulation, neural tube patterning, neural stem cell expansion and maintenance, lineage elaboration, differentiation, axonal path finding, and synaptogenesis. Although the molecular bases for these processes are largely unknown, RNA-based epigenetic mechanisms appear to be essential for orchestrating these precise and versatile biological phenomena and in defining the etiology of a spectrum of neurological diseases. The concerted modulation of RNA editing and the selective expression of non-protein-coding RNAs during seminal as well as continuous state transitions may comprise the plastic molecular code needed to couple the intrinsic malleability of neural network connections to evolving environmental influences to establish diverse forms of short- and long-term memory, context-specific behavioral responses, and sophisticated cognitive capacities.
Physiology and Neurobiology of Stress and Adaptation: Central Role of the Brain
Authors: McEwen Bruce S.
Published: July 2007

The brain is the key organ of the response to stress because it determines what is threatening and, therefore, potentially stressful, as well as the physiological and behavioral responses which can be either adaptive or damaging. Stress involves two-way communication between the brain and the cardiovascular, immune, and other systems via neural and endocrine mechanisms. Beyond the “flight-or-fight” response to acute stress, there are events in daily life that produce a type of chronic stress and lead over time to wear and tear on the body (“allostatic load”). Yet, hormones associated with stress protect the body in the short-run and promote adaptation (“allostasis”). The brain is a target of stress, and the hippocampus was the first brain region, besides the hypothalamus, to be recognized as a target of glucocorticoids. Stress and stress hormones produce both adaptive and maladaptive effects on this brain region throughout the life course. Early life events influence life-long patterns of emotionality and stress responsiveness and alter the rate of brain and body aging. The hippocampus, amygdala, and prefrontal cortex undergo stress-induced structural remodeling, which alters behavioral and physiological responses. As an adjunct to pharmaceutical therapy, social and behavioral interventions such as regular physical activity and social support reduce the chronic stress burden and benefit brain and body health and resilience.
Pathobiology of Cigarette Smoke-Induced Chronic Obstructive Pulmonary Disease
Authors: Yoshida Toshinori , Tuder Rubin M.
Published: July 2007

Chronic obstructive pulmonary diseases (COPD), comprised of pulmonary emphysema, chronic bronchitis, and structural and inflammatory changes of small airways, is a leading cause of morbidity and mortality in the world. A better understanding of the pathobiology of COPD is critical for the developing of novel therapies, as the majority of patients with the disease have little therapeutic options at the present time. The pathobiology of COPD encompasses multiple injurious processes including inflammation (excessive or inappropriate innate and adaptive immunity), cellular apoptosis, altered cellular and molecular alveolar maintenance program, abnormal cell repair, extracellular matrix destruction (protease and anti-protease imbalance), and oxidative stress (oxidant and antioxidant imbalance). These processes are triggered by urban and rural air pollutants and active and/or passive cigarette smoke and modified by cellular senescence and infection. A series of receptor-mediated signal transduction pathways are activated by reactive oxygen species and tobacco components, resulting in impairment of a variety of cell signaling and cytokine networks, subsequently leading to chronic airway responses with mucus production, airway remodeling, and alveolar destruction. The authors provide an updated insight into the molecular and cellular pathobiology of COPD based on human and/or animal data.
Organization and Ca2+Regulation of Adenylyl Cyclases in cAMP Microdomains
Authors: Willoughby Debbie , Cooper Dermot M. F.
Published: July 2007

The adenylyl cyclases are variously regulated by G protein subunits, a number of serine/threonine and tyrosine protein kinases, and Ca2+. In some physiological situations, this regulation can be readily incorporated into a hormonal cascade, controlling processes such as cardiac contractility or neurotransmitter release. However, the significance of some modes of regulation is obscure and is likely only to be apparent in explicit cellular contexts (or stages of the cell cycle). The regulation of many of the ACs by the ubiquitous second messenger Ca2+provides an overarching mechanism for integrating the activities of these two major signaling systems. Elaborate devices have been evolved to ensure that this interaction occurs, to guarantee the fidelity of the interaction, and to insulate the microenvironment in which it occurs. Subcellular targeting, as well as a variety of scaffolding devices, is used to promote interaction of the ACs with specific signaling proteins and regulatory factors to generate privileged domains for cAMP signaling. A direct consequence of this organization is that cAMP will exhibit distinct kinetics in discrete cellular domains. A variety of means are now available to study cAMP in these domains and to dissect their components in real time in live cells. These topics are explored within the present review.
Patterns of Known and Novel Small RNAs in Human Cervical Cancer
Authors: Lui Weng-Onn , Pourmand Nader , Patterson Bruce K. , Fire Andrew
Published: July 2007

Recent studies suggest that knowledge of differential expression of microRNAs (miRNA) in cancer may have substantial diagnostic and prognostic value. Here, we use a direct sequencing method to characterize the profiles of miRNAs and other small RNA segments for six human cervical carcinoma cell lines and five normal cervical samples. Of 166 miRNAs expressed in normal cervix and cancer cell lines, we observed significant expression variation of six miRNAs between the two groups. To further show the biological relevance of our findings, we examined the expression level of two significantly varying miRNAs in a panel of 29 matched pairs of human cervical cancer and normal cervical samples. Reduced expression of miR-143 and increased expression of miR-21 were reproducibly displayed in cancer samples, suggesting the potential value of these miRNAs as tumor markers. In addition to the known miRNAs, we found a number of novel miRNAs and an additional set of small RNAs that do not meet miRNA criteria. [Cancer Res 2007;67(13):6031–43]
High-Mobility Group A1 Proteins Inhibit Expression of Nucleotide Excision Repair Factor Xeroderma Pigmentosum Group A
Authors: Adair Jennifer E. , Maloney Scott C. , Dement Gregory A. , Wertzler Kelsey J. , Smerdon Michael J. , Reeves Raymond
Published: July 2007

Cells that overexpress high-mobility group A1 (HMGA1) proteins exhibit deficient nucleotide excision repair (NER) after exposure to DNA-damaging agents, a condition ameliorated by artificially lowering intracellular levels of these nonhistone proteins. One possible mechanism for this NER inhibition is down-regulation of proteins involved in NER, such as xeroderma pigmentosum complimentation group A (XPA). Microarray and reverse transcription-PCR data indicate a 2.6-fold decrease in intracellular XPA mRNA in transgenic MCF-7 cells overexpressing HMGA1 proteins compared with non–HMGA1-expressing cells. XPA protein levels are also ∼3-fold lower in HMGA1-expressing MCF-7 cells. Moreover, whereas a >2-fold induction of XPA proteins is observed in normal MCF-7 cells 30 min after UV exposure, no apparent induction of XPA protein is observed in MCF-7 cells expressing HMGA1. Mechanistically, we present both chromatin immunoprecipitation and promoter site-specific mutagenesis evidence linking HMGA1 to repression of XPA transcription via binding to a negative regulatory element in the endogenous XPA gene promoter. Phenotypically, HMGA1-expressing cells exhibit compromised removal of cyclobutane pyrimidine dimer lesions, a characteristic of cells that express low levels of XPA. Importantly, we show that restoring expression of wild-type XPA in HMGA1-expressing cells rescues UV resistance comparable with that of normal MCF-7 cells. Together, these data provide strong experimental evidence that HMGA1 proteins are involved in inhibiting XPA expression, resulting in increased UV sensitivity in cells that overexpress these proteins. Because HMGA1 proteins are overexpressed in most naturally occurring cancers, with increasing cellular concentrations correlating with increasing metastatic potential and poor patient prognosis, the current findings provide new insights into previously unsuspected mechanisms contributing to tumor progression. [Cancer Res 2007;67(13):6044–52]
Endothelin Receptor Type B Counteracts Tenascin-C–Induced Endothelin Receptor Type A–Dependent Focal Adhesion and Actin Stress Fiber Disorganization
Authors: Lange Katrin , Kammerer Martial , Hegi Monika E. , Grotegut Stefan , Dittmann Antje , Huang Wentao , Fluri Erika , Yip George W. , Götte Martin , Ruiz Christian , Orend Gertraud
Published: July 2007

Tenascin-C, an extracellular matrix molecule of the tumor-specific microenvironment, counteracts the tumor cell proliferation–suppressing effect of fibronectin by blocking the integrin α5β1/syndecan-4 complex. This causes cell rounding and stimulates tumor cell proliferation. Tenascin-C also stimulates endothelin receptor type A (EDNRA) expression. Here, we investigated whether signaling through endothelin receptors affects tenascin-C–induced cell rounding. We observed that endothelin receptor type B (EDNRB) activation inhibited cell rounding by tenascin-C and induced spreading by restoring expression and function of focal adhesion kinase (FAK), paxillin, RhoA, and tropomyosin-1 (TM1) via activation of epidermal growth factor receptor, phospholipase C, c-Jun NH2-terminal kinase, and the phosphatidylinositol 3-kinase pathway. In contrast to EDNRB, signaling through EDNRA induced cell rounding, which correlated with FAK inhibition and TM1 and RhoA protein destabilization in the presence of tenascin-C. This occurred in a mitogen-activated protein kinase/extracellular signal-regulated kinase kinase–dependent manner. Thus, tumorigenesis might be enhanced by tenascin-C involving EDNRA signaling. Inhibition of tenascin-C in combination with blocking both endothelin receptors could present a strategy for sensitization of cancer and endothelial cells toward anoikis. [Cancer Res 2007;67(13):6163–73]
Folate Receptor–Specific Antitumor Activity of EC131, a Folate-Maytansinoid Conjugate
Authors: Reddy Joseph A. , Westrick Elaine , Santhapuram Hari K.R. , Howard Stephen J. , Miller Michael L. , Vetzel Marilynn , Vlahov Iontcho , Chari Ravi V.J. , Goldmacher Victor S. , Leamon Christopher P.
Published: July 2007

EC131, a new folate receptor (FR)–targeted drug conjugate, was prepared by covalently attaching the vitamin folic acid (FA) to a potent microtubule-inhibiting agent, maytansinoid DM1, via an intramolecular disulfide bond. When tested on cells in culture, EC131 was found to retain high affinity for FR-positive cells and to provide FR-specific cytotoxicity with an IC50 in the low nanomolar range. The activity of EC131 was completely blocked in the presence of an excess of free FA, and no activity was detected against FR-negative cells. When evaluated against s.c. FR-positive M109 tumors in BALB/c mice, EC131 showed marked antitumor efficacy. Furthermore, this therapeutic effect occurred in the apparent absence of weight loss or noticeable organ tissue degeneration. In contrast, no significant antitumor activity was observed in EC131-treated animals that were codosed with an excess of FA, thus demonstrating the targeted specificity of the in vivo activity. EC131 also showed marked antitumor activity against FR-positive human KB tumors, but not against FR-negative A549 tumors, in nude mice with no evidence of systemic toxicity during or after the therapy. In contrast, therapy with the free maytansinoid drug (in the form of DM1-S-Me) proved not to be effective against the KB model when administered at its maximum tolerated dose (MTD). Taken together, these results indicate that EC131 is a highly potent agent capable of producing therapeutic benefit in murine tumor models at sub-MTD levels. [Cancer Res 2007;67(13):6376–82]
Adipose Tissue–Derived Human Mesenchymal Stem Cells Mediated Prodrug Cancer Gene Therapy
Authors: Kucerova Lucia , Altanerova Veronika , Matuskova Miroslava , Tyciakova Silvia , Altaner Cestmir
Published: July 2007

Human adipose tissue–derived mesenchymal stem cells (AT-MSC) are considered to be a promising source of autologous stem cells in personalized cell-based therapies. Tumor tracking properties of MSC provide an attractive opportunity for targeted transgene delivery into the sites of tumor formation. In the present study, we addressed whether the suicide gene introduction into human AT-MSC could produce a tumor-specific prodrug converting cellular vehicle for targeted chemotherapy. We prepared yeast fusion cytosine deaminase::uracil phosphoribosyltransferase gene–expressing cells [cytosine deaminase (CD)–expressing AT-MSC (CD-AT-MSC)] by retrovirus transduction. We explored their therapeutic potential on a model of human colon cancer in the presence of prodrug 5-fluorocytosine (5-FC). Gene manipulation of human AT-MSC did not sensitize CD-AT-MSC to 5-FC, thus overcoming the inherent disadvantage of suicide effect on cellular vehicle. CD-AT-MSC in combination with 5-FC augmented the bystander effect and selective cytotoxicity on target tumor cells HT-29 in direct coculture in vitro. We confirmed directed migration ability of AT-MSC and CD-AT-MSC toward tumor cells HT-29 in vitro. Moreover, we achieved significant inhibition of s.c. tumor xenograft growth by s.c. or i.v. administered CD-AT-MSC in immunocompromised mice treated with 5-FC. We confirmed the ability of CD-AT-MSC to deliver the CD transgene to the site of tumor formation and mediate strong antitumor effect in vivo. Taken together, these data characterize MSC derived from adipose tissue as suitable delivery vehicles for prodrug converting gene and show their utility for a personalized cell-based targeted cancer gene therapy. [Cancer Res 2007;67(13):6304–13]
Requirement for IFN-γ, CD8+ T Lymphocytes, and NKT Cells in Talactoferrin-Induced Inhibition of neu+ Tumors
Authors: Spadaro Michela , Curcio Claudia , Varadhachary Atul , Cavallo Federica , Engelmayer Jose , Blezinger Paul , Pericle Federica , Forni Guido
Published: July 2007

We have previously shown that talactoferrin-alfa (TLF), a recombinant human lactoferrin, is an immunomodulatory protein that is active against implanted tumors, both as a single agent and in combination with chemotherapy. In this study, we show that talactoferrin is active against autochthonous tumors in a transgenic mouse line, which is more analogous to human cancers, and identify key mechanistic steps involved in the anticancer activity of oral TLF. BALB/c mice transgenic for the rat neu (ErbB2) oncogene (BALB-neuT) treated with oral TLF showed a significant delay in carcinogenesis, with 60% tumor protection relative to vehicle-treated mice at week 21. Oral TLF also showed tumor growth inhibition in wild-type BALB/c mice implanted with neu+ mammary adenocarcinoma, with one third displaying a long-lasting or complete response. Oral TLF induces an increase in intestinal mucosal IFN-γ production and an increase in Peyer's patch cellularity, including expansion of CD8+ T lymphocytes and NKT cells, and the enhancement of CD8+ T-cell cytotoxicity. In IFN-γ knockout mice, there is an absence of the TLF-induced Peyer's patch cellularity, no expansion of CD8+ T lymphocytes and NKT cells, and loss of TLF anticancer activity. TLF antitumor activity is also lost in mice depleted of CD8+ T cells and in CD1 knockout mice, which lack NKT activity. Thus, the inhibition of distant tumors by oral TLF seems to be mediated by an IFN-γ–dependent enhancement of CD8+ T- and NKT cell activity initiated within the intestinal mucosa. [Cancer Res 2007;67(13):6425–32]
The RON Receptor Tyrosine Kinase Mediates Oncogenic Phenotypes in Pancreatic Cancer Cells and Is Increasingly Expressed during Pancreatic Cancer Progression
Authors: Thomas Ryan M. , Toney Kenya , Fenoglio-Preiser Cecilia , Revelo-Penafiel Monica P. , Hingorani Sunil R. , Tuveson David A. , Waltz Susan E. , Lowy Andrew M.
Published: July 2007

Pancreatic cancer is an aggressive disease characterized by rapid growth and early metastasis. The recepteur d'origine nantais (RON) receptor tyrosine kinase is overexpressed and/or constitutively active in several epithelial cancers, but its role in pancreatic cancer is unknown. In this study, we have characterized RON expression in both murine and human pancreatic cancer. Immunoblotting indicates that RON is expressed in pancreatic intraepithelial neoplasia (PanIN), primary, and metastatic cell lines both in the human and mouse. Immunostaining revealed that 93% of high-grade PanIN, 79% of primary, and 83% of metastatic lesions from human pancreatic tissue samples expressed RON, with minimal expression in normal ducts and low-grade PanIN (6% and 18%, respectively). Moreover, we show a dose-dependent effect of hepatocyte growth factor-like protein (HGFL), the RON-specific ligand, on pancreatic cancer cell migration and invasion, which was reversed by RON inhibition. Although stimulation with HGFL had no effect on proliferation, concurrent RON receptor blockade and gemcitabine treatment increased apoptosis of RON-expressing pancreatic cancer cells versus gemcitabine treatment alone. Finally, HGFL stimulation of pancreatic cancer cells resulted in increased expression of phospho-mitogen-activated protein kinase and phospho-Akt. Taken together, these findings suggest that RON receptor signaling may contribute to pancreatic carcinogenesis, and that further investigation is warranted to assess the potential of RON-directed therapies in this deadly disease. [Cancer Res 2007;67(13):6075–82]
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

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

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

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

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

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

Signal 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

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

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

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

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

The 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

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]
The Use of MDCT-Based Computer-Aided Pathway Finding for Mediastinal and Perihilar Lymph Node Biopsy: A Randomized Controlled Prospective Trial
Authors: McLennan Geoffrey , Ferguson J. Scott , Thomas Karl , Delsing Angela S. , Cook-Granroth Janice , Hoffman Eric A.
Published: July 2007

Background: Mediastinal and perihilar lymph node samples can be acquired safely through the transbronchial approach during a bronchoscopic examination that is usually required as part of the evaluation of suspected lung cancer. Typically, needle aspiration samples are performed and needle cores can be sampled if the operator is confident that the needle is within the lymph node target, partly because of the risk of bleeding if a large blood vessel is sampled during core biopsy, especially in the perihilar region. Many bronchoscopists have difficulty assessing the three-dimensional (3D) positioning for needle sampling during these procedures, especially when relying on multidetector-row computerized tomography (MDCT) images displayed two-dimensionally seen prior to and usually during the procedure. Objective: We have developed and evaluated a process model and associated software for providing interactive 3D displays of the MDCT data for procedure planning and real-time virtual bronchoscopic pathfinding for these procedures. Methods: We undertook a prospective randomized clinical study for evaluating the computer-aided pathfinding assistance in mediastinal lymph node biopsies in 87 consenting subjects. Results: We demonstrate that the addition of this computer-aided pathfinding improved operator performance in perihilar and paratracheal lymph node sampling (100 vs. 69%) but not in subcarinal sampling (82 vs. 85%). Overall success with lymph node sampling is 92% using the computer-aided method and 77% using standard clinical practice. Conclusions: The type of computer-aided pathway assistance described here, using 3D MDCT scanning information obtained before the procedure, but interacting with real-time bronchoscopic images during the bronchoscopic procedure, should improve the confidence of most bronchoscopists in performing these procedures, with improved clinical outcomes, and will add to the personalization of medicine through imaging.
Chronic Kidney Disease Management: Comparison between Renal Transplant Recipients and Nontransplant Patients with Chronic Kidney Disease
Authors: Akbari Ayub , Hussain Naser , Karpinski Jolanta , Knoll Greg A.
Published: July 2007

Background/Aim: Renal transplant recipients (RTR) and patients with native chronic kidney disease (CKD) have similar complications. It is not known how the management of CKD in RTR differs from that of patients with native CKD. This study compares the management of complications related to CKD between RTR and patients with native CKD. Methods: Cross-sectional study of all RTR with stage 4 or 5 CKD (n = 72). The control group consisted of 72 native CKD patients matched by glomerular filtration rate (within 2 ml/min/1.73 m2). Multivariate logistic regression analysis was performed to account for potential confounding variables. Results: Multivariate analysis revealed RTR to more likely have uncontrolled hypertension (adjusted odds ratio AOR 3.8; 95% confidence interval CI 1.3–10.7), less likely to be on angiotensin-converting enzyme inhibitors (AOR 0.11; 95% CI 0.04–0.32), more likely to be anemic and not be on erythropoietin (AOR 6.4; 95% CI 0.99–41.9), and more likely to have dyslipidemia and not be on statin (AOR 4.3; 95% CI 1.4–13.4). Conclusions: This study suggests that the management of non-RTR in a multidisciplinary CKD clinic differs significantly from the CKD management in a traditional transplant clinic. A disease management approach like a multidisciplinary clinic may be an appropriate model for the future.
Current Insights into Molecular Mechanisms of Alzheimer Disease and Their Implications for Therapeutic Approaches
Authors: Van Broeck Bianca , Van Broeckhoven Christine , Kumar-Singh Samir
Published: July 2007

During the last 10 years, a lot of progress has been made in unraveling the pathogenic cascade leading to Alzheimer disease (AD). According to the most widely accepted hypothesis, production and aggregation of the amyloid β (Aβ) peptide plays a key role in AD, and thus therapeutic interference with these processes is the subject of intense research. However, some important aspects of the disease mechanism are not yet fully understood. There is no consensus as yet on whether the disease acts through a loss- (LOF) or a gain-of-function (GOF) mechanism. While for many years, an increased production of Aβ42 was considered to be the prime culprit for the initiation of the disease process, and accordingly Aβ42 is elevated by AD-related presenilin(PS) mutations, recent data strongly suggest that PS mutations also lead to a LOF of PS towards a plethora of its substrates including amyloid precursor protein. How this PS LOF, especially decreased Aβ40 secretion due to mutant PS, impacts on the disease pathogenesis is yet to be elucidated. Secondly, vascular abnormalities – frequently observed to co-occur with AD – might also play a critical role in the initiation and aggravation of AD pathology given that the elimination of Aβ through a vascular route is an important brain Aβ clearance mechanism and its failure leads to formation of vascular amyloidosis and dense-core plaques. In this review, we will first focus on the important issue of a LOF versus a GOF mechanism for AD due to mutant PS, as well as on the possible role of vascular damage and reduced perfusion in AD. Special emphasis will be given to some of the AD mouse models that have helped to gain insights into the disease mechanism. Secondly, considering these mechanistic insights, we will discuss some therapeutic strategies which are currently in clinical or preclinical trials for AD.
Identification of a Novel Valosin-Containing Protein Polymorphism in Late-Onset Alzheimer’s Disease
Authors: Kaleem M. , Zhao A. , Hamshere M. , Myers A.J.
Published: July 2007

Background/Aims: Recently, mutations in the valosin-containing protein gene (VCP) were found to be causative for a rare form of dementia [Watts GDJ, et al.: Nat Genet 2004;36:377–381]. This gene lies within a region on the genome that has been linked to late onset Alzheimer’s disease (LOAD) [Myers A, et al.: Am J Med Genet 2002;114:233–242]. In this study, we investigated whether variation within VCP could account for the LOAD linkage peak on chromosome 9. Methods: We sequenced 188 individuals from the set of sibling pairs we had used to obtain the linkage results for chromosome 9 to look for novel polymorphisms that could explain the linkage signal. Any variant that was found was then typed in 2 additional sets of neuropathologically confirmed samples to look for associations with Alzheimer’s disease. Results: We found 2 variants when we sequenced VCP. One was a novel rare variant (R92H) and the other is already reported within the publicly available databases (rs10972300). Neither explained the chromosome 9 linkage signal for LOAD. Conclusions: We have found a novel rare variant within the VCP gene, but we did not find a variant that could explain the linkage signal for LOAD on chromosome 9.