bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simian Virus 40 Large T Antigen Can Specifically Unwind the Central Palindrome at the Origin of DNA Replication
Authors: Wang Weiping , Simmons Daniel T. 
Published: January 2009

ABSTRACT
The hydrophilic channels between helicase domains of simian virus 40 (SV40) large T antigen play a critical role in DNA replication. Previous mutagenesis of residues in the channels identified one class of mutants (class A: D429A, N449S, and N515S) with normal DNA binding and ATPase and helicase activities but with a severely reduced ability to unwind origin DNA and to support SV40 DNA replication in vitro. Here, we further studied these mutants to gain insights into how T antigen unwinds the origin. We found that the mutants were compromised in melting the imperfect palindrome (EP) but normal in untwisting the AT-rich track. However, the mutants' defect in EP melting was not the major reason they failed to unwind the origin because supplying an EP region as a mismatched bubble, or deleting the EP region altogether, did not rescue their unwinding deficiency. These results suggested that specific separation of the central palindrome of the origin (site II) is an essential step in unwinding origin DNA by T antigen. In support of this, wild-type T antigen was able to specifically unwind a 31-bp DNA containing only site II in an ATPase-dependent reaction, whereas D429A and N515S failed to do so. By performing a systematic mutagenesis of 31-bp site II DNA, we identified discrete regions in each pentanucleotide necessary for normal origin unwinding. These data indicate that T antigen has a mechanism to specifically unwind the central palindrome. Various models are proposed to illustrate how T antigen could separate the central origin.
5′
cis
Elements Direct Nodavirus RNA1 Recruitment to Mitochondrial Sites of Replication Complex Formation
Authors: Van Wynsberghe Priscilla M. , Ahlquist Paul 
Published: January 2009

ABSTRACT

Positive-strand RNA viruses replicate their genomes on intracellular membranes, usually in conjunction with virus-induced membrane rearrangements. For the nodavirus flock house virus (FHV), we recently showed that multifunctional FHV replicase protein A induces viral RNA template recruitment to a membrane-associated state, but the site(s) and function of this recruitment were not determined. By tagging viral RNA with green fluorescent protein, we show here in
Drosophila
cells that protein A recruits FHV RNA specifically to the outer mitochondrial membrane sites of RNA replication complex formation. Using
Drosophila
cells and yeast cells, which also support FHV replication, we also defined the
cis
-acting regions that direct replication and template recruitment for FHV genomic RNA1. RNA1 nucleotides 68 to 205 were required for RNA replication and directed efficient protein A-mediated RNA recruitment in both cell types. RNA secondary structure prediction, structure probing, and phylogenetic comparisons in this region identified two stable, conserved stem-loops with nearly identical loop sequences. Further mutational analysis showed that both stem-loops and certain flanking sequences were required for RNA1 recruitment, negative-strand synthesis, and subsequent positive-strand amplification in yeast and
Drosophila
cells. Thus, we have shown that protein A recruits RNA1 templates to mitochondria, as expected for RNA replication, and identified a new RNA1
cis
element that is necessary and sufficient for RNA1 template recognition and recruitment to these mitochondrial membranes for negative-strand RNA1 synthesis. These results establish RNA recruitment to the sites of replication complex formation as an essential, distinct, and selective early step in nodavirus replication.
Discovery of Herpes B Virus-Encoded MicroRNAs
Authors: Besecker Michael I. , Harden Mallory E. , Li Guanglin , Wang Xiu-Jie , Griffiths Anthony 
Published: January 2009

ABSTRACT
Herpes B virus (BV) naturally infects macaque monkeys and is a close relative of herpes simplex virus. BV can zoonotically infect humans to cause a rapidly ascending encephalitis with ∼80% mortality. Therefore, BV is a serious danger to those who come into contact with these monkeys or their tissues and cells. MicroRNAs are regulators of gene expression, and there have been reports of virus-encoded microRNAs. We hypothesize that BV-encoded microRNAs are important for the regulation of viral and cellular genes. Herein, we report the discovery of three herpes B virus-encoded microRNAs.
Helicobacter pyloriCytotoxin-Associated Gene A Activates the Signal Transducer and Activator of Transcription 3 PathwayIn vitroandIn vivo
Authors: Bronte-Tinkew Dana M. , Terebiznik Mauricio , Franco Aime , Ang Michelle , Ahn Diane , Mimuro Hitomi , Sasakawa Chihiro , Ropeleski Mark J. , Peek Richard M. , Jones Nicola L. 
Published: January 2009

AbstractPersistent infection with Helicobacter pylori confers an increased risk for the development of gastric cancer. However, the exact mechanisms whereby this bacterium causes carcinogenesis have not been completely elucidated. Recent evidence indicates that aberrant activation of the signal transducers and activators of transcription 3 (STAT3) signaling pathway may play a role in gastric carcinogenesis. Therefore, we hypothesized that H. pylori infection modulates STAT3 signaling, favoring gastric cancer development. In epithelial cells infected with H. pylori, STAT3 was activated, as assessed by immunoblotting for phosphorylated STAT3, immunofluorescence of translocated STAT3, fluorescence recovery after photobleaching, and luciferase activation in transfected cells. Activation was dependent on translocation but not phosphorylation of cytotoxin-associated gene A (CagA) in host cells. Activation seemed to be receptor-mediated because preincubation of cells with the interleukin-6 (IL-6) receptor superantagonist sant7 or inhibition of gp130 by a monoclonal antibody prevented H. pylori–mediated STAT3 activation. However, activation was not related to autocrine activation by IL-6 or IL-11. CagA+ wild-type H. pylori, but not the noncarcinogenic cagA− mutant, activated STAT3 in gastric epithelial cells in vivo in the gerbil model of H. pylori–mediated gastric carcinogenesis. Collectively, these results indicate that H. pylori CagA activates the STAT3 signaling pathway in vitro and in vivo, providing a potential mechanism by which chronic H. pylori infection promotes the development of gastric cancer. [Cancer Res 2009;69(2):632–9]
High Frequency of TP53 Mutation in BRCA1 and Sporadic Basal-like Carcinomas but not in BRCA1 Luminal Breast Tumors
Authors: Manié Elodie , Vincent-Salomon Anne , Lehmann-Che Jacqueline , Pierron Gaelle , Turpin Elisabeth , Warcoin Mathilde , Gruel Nadège , Lebigot Ingrid , Sastre-Garau Xavier , Lidereau Rosette , Remenieras Audrey , Feunteun Jean , Delattre Olivier , de Thé Hugues , Stoppa-Lyonnet Dominique , Stern Marc-Henri 
Published: January 2009

Abstract
Breast tumors with a germ-line mutation of BRCA1 (BRCA1 tumors) and basal-like carcinoma (BLC) are associated with a high rate of TP53 mutation. Because BRCA1 tumors frequently display a basal-like phenotype, this study was designed to determine whether TP53 mutations are correlated with the hereditary BRCA1 mutated status or the particular phenotype of these tumors. The TP53 gene status was first investigated in a series of 35 BRCA1 BLCs using immunohistochemistry, direct sequencing of the coding sequence, and functional analysis of separated alleles in yeast, and compared with the TP53 status in a series of 38 sporadic (nonhereditary) BLCs. Using this sensitive approach, TP53 was found to be frequently mutated in both BRCA1 (34 of 35, 97%) and sporadic (35 of 38, 92%) BLCs. However, the spectrum of mutation was different, particularly with a higher rate of complex mutations, such as insertion/deletion, in BRCA1 BLCs than in the sporadic group [14 of 33 (42%) and 13 of 34 (9%), respectively; P = 0.002]. Secondly, the incidence of TP53 mutations was analyzed in 19 BRCA1 luminal tumors using the same strategy. Interestingly, only 10 of these 19 tumors were mutated (53%), a frequency similar to that found in grade-matched sporadic luminal tumors. In conclusion, TP53 mutation is highly recurrent in BLCs independently of BRCA1 status, but not a common feature of BRCA1 luminal tumors. [Cancer Res 2009;69(2):663–71]
Down-regulation of Rap1GAP via Promoter Hypermethylation Promotes Melanoma Cell Proliferation, Survival, and Migration
Authors: Zheng Hong , Gao Ling , Feng Yunfeng , Yuan Liya , Zhao Haibo , Cornelius Lynn A. 
Published: January 2009

AbstractMelanoma is the most serious, highly aggressive form of skin cancer with recent dramatic increases in incidence. Current therapies are relatively ineffective, highlighting the need for a better understanding of the molecular mechanisms contributing to the disease. We have previously shown that activation of Rap1 promotes melanoma cell proliferation and migration through the mitogen-activated protein kinase pathway and integrin activation. In the present study, we show that expression of Rap1GAP, a specific negative regulator of Rap1, is decreased in human melanoma tumors and cell lines. Overexpression of Rap1GAP in melanoma cells blocks Rap1 activation and extracellular signal-regulated kinase (ERK) phosphorylation and inhibits melanoma cell proliferation and survival. In addition, overexpression of Rap1GAP also inhibits focal adhesion formation and decreases melanoma cell migration. Rap1GAP down-regulation is due to its promoter methylation, a mechanism of gene silencing in tumors. Furthermore, treatment of melanoma cells with the demethylating agent 5-aza-2'-deoxycytidine reinduces Rap1GAP expression, followed by decreased Rap1 activity, ERK phosphorylation, and cell proliferation and survival—changes that are significantly blunted in cells transfected by small interfering RNA–mediated Rap1GAP knockdown. Taken together, our findings indicate that down-regulation of Rap1GAP via promoter hypermethylation promotes melanoma cell proliferation, survival, and migration. [Cancer Res 2009;69(2):449–57]
Epigallocatechin-3-Gallate, a Histone Acetyltransferase Inhibitor, Inhibits EBV-Induced B Lymphocyte Transformation via Suppression of RelA Acetylation
Authors: Choi Kyung-Chul , Jung Myung Gu , Lee Yoo-Hyun , Yoon Joo Chun , Kwon Seung Hyun , Kang Hee-Bum , Kim Mi-Jeong , Cha Jeong-Heon , Kim Young Jun , Jun Woo Jin , Lee Jae Myun , Yoon Ho-Geun 
Published: January 2009

Abstract
Because the p300/CBP-mediated hyperacetylation of RelA (p65) is critical for nuclear factor-κB (NF-κB) activation, the attenuation of p65 acetylation is a potential molecular target for the prevention of chronic inflammation. During our ongoing screening study to identify natural compounds with histone acetyltransferase inhibitor (HATi) activity, we identified epigallocatechin-3-gallate (EGCG) as a novel HATi with global specificity for the majority of HAT enzymes but with no activity toward epigenetic enzymes including HDAC, SIRT1, and HMTase. At a dose of 100 μmol/L, EGCG abrogates p300-induced p65 acetylation in vitro and in vivo, increases the level of cytosolic IκBα, and suppresses tumor necrosis factor α (TNFα)–induced NF-κB activation. We also showed that EGCG prevents TNFα-induced p65 translocation to the nucleus, confirming that hyperacetylation is critical for NF-κB translocation as well as activity. Furthermore, EGCG treatment inhibited the acetylation of p65 and the expression of NF-κB target genes in response to diverse stimuli. Finally, EGCG reduced the binding of p300 to the promoter region of interleukin-6 gene with an increased recruitment of HDAC3, which highlights the importance of the balance between HATs and histone deacetylases in the NF-κB–mediated inflammatory signaling pathway. Importantly, EGCG at 50 μmol/L dose completely blocks EBV infection-induced cytokine expression and subsequently the EBV-induced B lymphocyte transformation. These results show the crucial role of acetylation in the development of inflammatory-related diseases. [Cancer Res 2009;69(2):583–92]
MicroRNA Silencing in Primates: Towards Development of Novel Therapeutics
Authors: Petri Andreas , Lindow Morten , Kauppinen Sakari 
Published: January 2009

Abstract
MicroRNAs (miRNA) comprise an abundant class of small noncoding RNAs that act as important posttranscriptional regulators of gene expression. Accumulating evidence showing that aberrantly expressed miRNAs play important roles in human cancers underscores them as potential targets for therapeutic intervention. Recent reports on efficient miRNA silencing in rodents and nonhuman primates using high-affinity targeting by chemically modified antisense oligonucleotides highlight the utility of such compounds in the development of miRNA-based cancer therapeutics. [Cancer Res 2009;69(2):393–5]
Modulation of G Protein Signaling Normalizes Tumor Vessels
Authors: Manzur Mitali , Hamzah Juliana , Ganss Ruth 
Published: January 2009

AbstractG protein–coupled biological processes are important for an ever-increasing number of human diseases and require fine-tuning through accessory molecules such as the regulators of G protein signaling (RGS). RGS5, a marker for tumor-resident pericytes, was recently established as playing a pivotal role in vascular maturation and vessel remodeling during carcinogenesis. Remarkably, tumors arising in a RGS5-deficient background display vessels with normalized morphology and an overall improved blood flow. Furthermore, these morphologic changes also lead to dramatic improvements in lymphocyte access to tumors and success of antitumor immunotherapy. Here, we consider the implications of these findings, and how they contribute to enhancing our understanding of remodeling angiogenic vessels as means for improving anticancer therapies. [Cancer Res 2009;69(2):396–9]
Protein Kinase C βII and PKCι/λ: Collaborating Partners in Colon Cancer Promotion and Progression
Authors: Murray Nicole R. , Weems Justin , Braun Ursula , Leitges Michael , Fields Alan P. 
Published: January 2009

Abstract
We previously showed that elevated expression of either protein kinase CβII (PKCβII) or PKCι/λ enhances colon carcinogenesis in mice. Here, we use novel bitransgenic mice to determine the relative importance of PKCβII and PKCι/λ in colon carcinogenesis in two complimentary models of colon cancer in vivo. Bitransgenic mice overexpressing PKCβII and constitutively active PKCι (PKCβII/caPKCι) or kinase-deficient, dominant-negative PKCι (PKCβII/kdPKCι) in the colon exhibit a similar increase in colon tumor incidence, tumor size, and tumor burden in response to azoxymethane (AOM) when compared with nontransgenic littermates. However, PKCβII/kdPKCι mice develop predominantly benign colonic adenomas, whereas PKCβII/caPKCι mice develop malignant carcinomas. In contrast, PKCβ-deficient (PKCβ−/−) mice fail to develop tumors even in the presence of caPKCι. Our previous data indicated that PKCβII drives tumorigenesis and proliferation by activating β-catenin/Apc signaling. Consistent with this conclusion, genetic deletion of PKCβ has no effect on spontaneous tumorigenesis in Apcmin/+ mice. In contrast, tissue-specific knockout of PKCλ significantly suppresses intestinal tumor formation in Apcmin/+ mice. Our data show that PKCβII and PKCι/λ serve distinct, nonoverlapping functions in colon carcinogenesis. PKCβII is required for AOM-induced tumorigenesis but is dispensable for tumor formation in ApcMin/+ mice. PKCι/λ promotes tumor progression in both AOM- and Apcmin/+-induced tumorigenesis. Thus, PKCβII and PKCι, whose expression is elevated in both rodent and human colon tumors, collaborate to drive colon tumor formation and progression, respectively. [Cancer Res 2009;69(2):656–62]
Potentiating Endogenous Antitumor Immunity to Prostate Cancer through Combination Immunotherapy with CTLA4 Blockade and GM-CSF
Authors: Fong Lawrence , Kwek Serena S. , O'Brien Shaun , Kavanagh Brian , McNeel Douglas G. , Weinberg Vivian , Lin Amy M. , Rosenberg Jonathan , Ryan Charles J. , Rini Brian I. , Small Eric J. 
Published: January 2009

Abstract
CTL-associated antigen 4 (CTLA4) is a costimulatory molecule expressed on activated T cells that delivers an inhibitory signal to these T cells. CTLA4 blockade with antibody treatment has been shown to augment antitumor immunity in animal models and is being developed as a treatment for cancer patients. As has been seen in preclinical models, combining CTLA4 blockade and granulocyte macrophage colony-stimulating factor (GM-CSF)–based immunotherapies can enhance the antitumor efficacy of this approach. We therefore examined whether CTLA4 blockade could be combined with GM-CSF administration. We treated 24 patients with metastatic, castration-resistant prostate cancer in a phase I trial where sequential cohorts were treated with increasing doses of ipilimumab, a fully human anti-CTLA4 antibody. Study subjects also received s.c. injections of GM-CSF at a fixed dose. Of the six patients treated at the highest dose level, three had confirmed PSA declines of &gt;50%, including one patient that had a partial response in visceral metastases. Expansion of activated, circulating CD25+ CD69+ CD8+ T cells occurred more frequently at higher doses of treatment and was greater in magnitude than was seen in patients who received the same doses of either ipilimumab or GM-CSF alone. By screening sera with protein arrays, we showed that our treatment can induce antibody responses to NY-ESO-1. These results show that this combination immunotherapy can induce the expansion not only of activated effector CD8 T cells in vivo but also of T cells that are specific for known tumor-associated antigens from the endogenous immune repertoire. [Cancer Res 2009;69(2):609–15]
Targeting Inflammatory Pathways for Prevention and Therapy of Cancer: Short-Term Friend, Long-Term Foe
Authors: Aggarwal Bharat B. , Vijayalekshmi R.V. , Sung Bokyung 
Published: January 2009

AbstractChronic infections, obesity, alcohol, tobacco, radiation, environmental pollutants, and high-calorie diet have been recognized as major risk factors for the most common types of cancer. All these risk factors are linked to cancer through inflammation. Although acute inflammation that persists for short-term mediates host defense against infections, chronic inflammation that lasts for long term can predispose the host to various chronic illnesses, including cancer. Linkage between cancer and inflammation is indicated by numerous lines of evidence; first, transcription factors nuclear factor-κB (NF-κB) and signal transducers and activators of transcription 3 (STAT3), two major pathways for inflammation, are activated by most cancer risk factors; second, an inflammatory condition precedes most cancers; third, NF-κB and STAT3 are constitutively active in most cancers; fourth, hypoxia and acidic conditions found in solid tumors activate NF-κB; fifth, chemotherapeutic agents and γ-irradiation activate NF-κB and lead to chemoresistance and radioresistance; sixth, most gene products linked to inflammation, survival, proliferation, invasion, angiogenesis, and metastasis are regulated by NF-κB and STAT3; seventh, suppression of NF-κB and STAT3 inhibits the proliferation and invasion of tumors; and eighth, most chemopreventive agents mediate their effects through inhibition of NF-κB and STAT3 activation pathways. Thus, suppression of these proinflammatory pathways may provide opportunities for both prevention and treatment of cancer.
The Expression of Phospho-AKT, Phospho-mTOR, and PTEN in Extrahepatic Cholangiocarcinoma
Authors: Chung Joon-Yong , Hong Seung-Mo , Choi Byeong Yeob , Cho HyungJun , Yu Eunsil , Hewitt Stephen M. 
Published: January 2009

Abstract
Purpose: The protein kinase B (AKT) pathway plays a key role in the regulation of cellular survival, apoptosis, and protein translation, and has been shown to have prognostic significance in a number of cancers. We sought to define its role in extrahepatic cholangiocarcinoma.
Experimental Design: Two hundred twenty-one extrahepatic cholangiocarcinoma patients with clinicopathologic data, including survival, were arrayed into tissue microarrays. Phosphorylated AKT (p-AKT), phosphorylated mammalian target of rapamycin (p-mTOR), and total phosphatase and tensin homolog deleted on chromosome 10 (PTEN) protein expressions were studied with multiplex tissue immunoblotting assay.
Results: Expressions of p-AKT and p-mTOR were significantly increased in extrahepatic cholangiocarcinoma cases compared with normal and dysplastic bile duct epithelium (P &lt; 0.05 both). Decreased PTEN expression was observed in patients with increasing depth of invasion (P &lt; 0.05), T classification (P &lt; 0.05), and stage grouping (P &lt; 0.05), and the presence of invasion of the pancreas (P &lt; 0.05) and duodenum (P &lt; 0.05). Decreased PTEN expression (P = 0.004) as well as decreased PTEN/p-AKT (P = 0.003) and PTEN/p-mTOR (P = 0.009) expression showed shorter survival by univariate but not by multivariate analysis.
Conclusions: The AKT pathway is activated in a subset of extrahepatic cholangiocarcinoma. Elevated PTEN expression correlates with longer survival. Quantitative data obtained by multiplex tissue immunoblotting may provide additional information than assessment of immunohistochemistry alone. Quantitative analysis of PTEN, PTEN/p-AKT and PTEN/p-mTOR shows differences in survival by univariate analysis.
Improvement of Gemcitabine-Based Therapy of Pancreatic Carcinoma by Means of Oncolytic Parvovirus H-1PV
Authors: Angelova Assia L. , Aprahamian Marc , Grekova Svitlana P. , Hajri Amor , Leuchs Barbara , Giese Nathalia A. , Dinsart Christiane , Herrmann Alexia , Balboni Ginette , Rommelaere Jean , Raykov Zahari 
Published: January 2009

Abstract
Pancreatic carcinoma is a gastrointestinal malignancy with poor prognosis. Treatment with gemcitabine, the most potent chemotherapeutic against this cancer up to date, is not curative, and resistance may appear. Complementary treatment with an oncolytic virus, such as the rat parvovirus H-1PV, which is infectious but nonpathogenic in humans, emerges as an innovative option.
Purpose: To prove that combining gemcitabine and H-1PV in a model of pancreatic carcinoma may reduce the dosage of the toxic drug and/or improve the overall anticancer effect.
Experimental Design: Pancreatic tumors were implanted orthotopically in Lewis rats or subcutaneously in nude mice and treated with gemcitabine, H-1PV, or both according to different regimens. Tumor size was monitored by micro-computed tomography, whereas bone marrow, liver, and kidney functions were monitored by measuring clinically relevant markers. Human pancreatic cell lines and gemcitabine-resistant derivatives were tested in vitro for sensitivity to H-1PV infection with or without gemcitabine.
Results: In vitro studies proved that combining gemcitabine with H-1PV resulted in synergistic cytotoxic effects and achieved an up to 15-fold reduction in the 50% effective concentration of the drug, with drug-resistant cells remaining sensitive to virus killing. Toxicologic screening showed that H-1PV had an excellent safety profile when applied alone or in combination with gemcitabine. The benefits of applying H-1PV as a second-line treatment after gemcitabine included reduction of tumor growth, prolonged survival of the animals, and absence of metastases on CT-scans.
Conclusion: In addition to their potential use as monotherapy for pancreatic cancer, parvoviruses can be best combined with gemcitabine in a two-step protocol.