bluuebunny/crossref_metadata_2025_split huggingface dataset:
Curcumin Decreases Specificity Protein Expression in Bladder Cancer Cells
Authors: Chadalapaka Gayathri , Jutooru Indira , Chintharlapalli Sudhakar , Papineni Sabitha , Smith Roger , Li Xiangrong , Safe Stephen 
Published: July 2008

Abstract
Curcumin is the active component of tumeric, and this polyphenolic compound has been extensively investigated as an anticancer drug that modulates multiple pathways and genes. In this study, 10 to 25 μmol/L curcumin inhibited 253JB-V and KU7 bladder cancer cell growth, and this was accompanied by induction of apoptosis and decreased expression of the proapoptotic protein survivin and the angiogenic proteins vascular endothelial growth factor (VEGF) and VEGF receptor 1 (VEGFR1). Because expression of survivin, VEGF, and VEGFR1 are dependent on specificity protein (Sp) transcription factors, we also investigated the effects of curcumin on Sp protein expression as an underlying mechanism for the apoptotic and antiangiogenic activity of this compound. The results show that curcumin induced proteasome-dependent down-regulation of Sp1, Sp3, and Sp4 in 253JB-V and KU7 cells. Moreover, using RNA interference with small inhibitory RNAs for Sp1, Sp3, and Sp4, we observed that curcumin-dependent inhibition of nuclear factor κB (NF-κB)–dependent genes, such as bcl-2, survivin, and cyclin D1, was also due, in part, to loss of Sp proteins. Curcumin also decreased bladder tumor growth in athymic nude mice bearing KU7 cells as xenografts and this was accompanied by decreased Sp1, Sp3, and Sp4 protein levels in tumors. These results show for the first time that one of the underlying mechanisms of action of curcumin as a cancer chemotherapeutic agent is due, in part, to decreased expression of Sp transcription factors in bladder cancer cells. [Cancer Res 2008;68(13):5345–54]
Curcumin Blocks RON Tyrosine Kinase–Mediated Invasion of Breast Carcinoma Cells
Authors: Narasimhan Madhusudhanan , Ammanamanchi Sudhakar 
Published: July 2008

Abstract
We have recently shown that macrophage-stimulating protein (MSP) promotes the invasion of recepteur d'origine nantais (RON), a tyrosine kinase receptor–positive MDA-MB-231, MDA-MB-468 breast cancer cells, and also identified the regulatory elements required for RON gene expression. In this report, we have analyzed the efficacy of a chemopreventive agent, curcumin, in blocking RON tyrosine kinase–mediated invasion of breast cancer cells. Reverse transcription-PCR and Western analysis indicated the down-regulation of the RON message and protein, respectively, in MDA-MB-231 and MDA-MB-468 cells. Significantly, curcumin-mediated inhibition of RON expression resulted in the blockade of RON ligand, MSP-induced invasion of breast cancer cells. We have identified two putative nuclear factor-κB p65 subunit binding sites on the RON promoter. Using chromatin immunoprecipitation analysis and site-directed mutagenesis of the RON promoter, we have confirmed the binding of p65 to the RON promoter. Our data show that curcumin reduces RON expression by affecting p65 protein expression and transcriptional activity. Treatment of MDA-MB-231 cells with pyrrolidine dithiocarbamate, an inhibitor of p65, or small interfering RNA knockdown of p65, blocked RON gene expression and MSP-mediated invasion of MDA-MB-231 cells. This is the first report showing the regulation of human RON gene expression by nuclear factor-κB and suggests a potential therapeutic role for curcumin in blocking RON tyrosine kinase–mediated invasion of carcinoma cells. [Cancer Res 2008;68(13):5185–92]
Increasing Melanoma Cell Death Using Inhibitors of Protein Disulfide Isomerases to Abrogate Survival Responses to Endoplasmic Reticulum Stress
Authors: Lovat Penny E. , Corazzari Marco , Armstrong Jane L. , Martin Shaun , Pagliarini Vittoria , Hill David , Brown Anna M. , Piacentini Mauro , Birch-Machin Mark A. , Redfern Christopher P.F. 
Published: July 2008

AbstractExploiting vulnerabilities in the intracellular signaling pathways of tumor cells is a key strategy for the development of new drugs. The activation of cellular stress responses mediated by the endoplasmic reticulum (ER) allows cancer cells to survive outside their normal environment. Many proteins that protect cells against ER stress are active as protein disulfide isomerases (PDI) and the aim of this study was to test the hypothesis that apoptosis in response to ER stress can be increased by inhibiting PDI activity. We show that the novel chemotherapeutic drugs fenretinide and velcade induce ER stress–mediated apoptosis in melanoma cells. Both stress response and apoptosis were enhanced by the PDI inhibitor bacitracin. Overexpression of the main cellular PDI, procollagen-proline, 2-oxoglutarate-4-dioxygenase β subunit (P4HB), resulted in increased PDI activity and abrogated the apoptosis-enhancing effect of bacitracin. In contrast, overexpression of a mutant P4HB lacking PDI activity did not increase cellular PDI activity or block the effects of bacitracin. These results show that inhibition of PDI activity increases apoptosis in response to agents which induce ER stress and suggest that the development of potent, small-molecule PDI inhibitors has significant potential as a powerful tool for enhancing the efficacy of chemotherapy in melanoma. [Cancer Res 2008;68(13):5363–8]
Improved Therapeutic Results by Pretargeted Radioimmunotherapy of Non–Hodgkin's Lymphoma with a New Recombinant, Trivalent, Anti-CD20, Bispecific Antibody
Authors: Sharkey Robert M. , Karacay Habibe , Litwin Samuel , Rossi Edmund A. , McBride William J. , Chang Chien-Hsing , Goldenberg David M. 
Published: July 2008

Abstract
We examined whether a pretargeting method using a new recombinant anti-CD20 bispecific antibody (bsMAb) followed by 90Y-1,4,7,10-tetraazacyclododecane-N,N′,N′′,N′′′-tetraacetic acid (90Y-DOTA)-peptide could reduce hematologic toxicity yet improve therapeutic responses compared with conventional 90Y-anti-CD20 IgG and a chemically conjugated bsMAb. TF4, a humanized, tri-Fab bsMAb with two Fabs binding CD20 and one Fab binding histamine-succinyl-glycine (HSG), developed by the dock and lock (DNL) method, was tested in nude mice with Ramos B-cell lymphomas. Optimal pretargeting required a 29-h interval between TF4 and 90Y-DOTA-HSG, and 20-fold more moles of TF4. TF4 cleared more rapidly from the blood than anti-CD20 IgG, with early processing in the liver, spleen, and kidney. At 24 h, TF4 improved tumor uptake of 111In-HSG-peptide 2.6-fold [13% versus 5% injected dose per gram (ID/g)] and enhanced tumor to blood ratios &gt;45-fold (770 versus 17), compared with an anti-CD20 Fab × anti-HSG Fab chemical conjugate, and by 1.6-fold (9.0% versus 5.6% ID/g) and 1,600-fold (522 versus 0.32), respectively, compared with radiolabeled anti-CD20 IgG. A severe (≥90%) and prolonged reduction of WBCs was observed at the maximum dose of 90Y-anti-CD20 IgG, whereas pretargeting resulted in a ≤60% transient drop. TF4 pretargeting resulted in highly significant improvement in survival, curing 33% to 90% of the animals, even at relatively low doses, whereas most tumors progressed quickly without cures with 90Y-anti-CD20 IgG. These results indicate an improved therapeutic index with pretargeted radioimmunotherapy (RAIT) using a DNL-constructed tri-Fab, bsMAb, compared with conventional therapy with directly radiolabeled antibody or with a chemically conjugated bsMAb. These encouraging results prompt testing these constructs for pretargeting RAIT in patients. [Cancer Res 2008;68(13):5282–90]
Haploinsufficiency of the Maspin Tumor Suppressor Gene Leads to Hyperplastic Lesions in Prostate
Authors: Shao Long-jiang , Shi Heidi Y. , Ayala Gustavo , Rowley David , Zhang Ming 
Published: July 2008

Abstract
Maspin is a key tumor suppressor gene in prostate and breast cancers with diverse biological functions. However, how maspin regulates prostate tumor progression is not fully understood. In this study, we have used maspin heterozygous knockout mice to determine the effect of maspin haploinsufficiency on prostate development and tumor progression. We report that loss of one copy of maspin gene in Mp+/− heterozygous knockout mice leads to the development of prostate hyperplastic lesions, and this effect was mediated through decreased level of cyclin-dependent kinase inhibitors p21 and p27. Prostate hyperplastic lesions in Mp+/− mice also induced stromal reaction, which occurred in both aged prostate tissues and in neonatal prostates during early ductal morphogenesis. We showed that maspin was also expressed in prostate smooth muscle cells (PSMC), and recombinant maspin increased PSMC cell adhesion but inhibited cell proliferation. We also observed a defective interaction between epithelial cells and basement membrane in the prostate of Mp+/− mice, which was accompanied with a changed pattern of matrix deposition and a loss of epithelial cell polarity. Therefore, we have identified a novel property of maspin, which involves the control of the proliferation in prostate epithelial and smooth muscle cells. This is the first report that a partial loss of maspin caused an early developmental defect of the prostate and prostate hyperplastic lesions in mouse. [Cancer Res 2008;68(13):5143–51]
miR-206 Expression Is Down-regulated in Estrogen Receptor α–Positive Human Breast Cancer
Authors: Kondo Naoto , Toyama Tatsuya , Sugiura Hiroshi , Fujii Yoshitaka , Yamashita Hiroko 
Published: July 2008

Abstract
Expression levels of estrogen receptor (ER) α govern estrogen-dependent growth, response to endocrine therapy, and prognosis in ERα-positive breast cancer. Multiple mechanisms involved in altering ERα gene expression in breast cancer have been identified, including ERα gene amplification as well as transcriptional silencing by DNA methylation of CpG islands within the ERα promoter and mutations within the open reading frame of ERα. However, expression levels of ERα in breast cancer tissues differ widely among patients, and frequently change during disease progression and in response to systemic therapies. Recent evidence has shown that microRNA mutations or misexpression correlate with various human cancers, and miR-206 is reported to decrease endogenous ERα mRNA and protein levels in human MCF-7 breast cancer cells via two specific target sites within the 3′-untranslated region of the human ERα transcript. In this study, we show for the first time that miR-206 expression is markedly decreased in ERα-positive human breast cancer tissues assayed by quantitative reverse transcription-PCR analysis. Moreover, we observe that miR-206 expression is inversely correlated with ERα but not ERβ mRNA expression in breast cancer tissues. Transfection experiments revealed that introduction of miR-206 into estrogen-dependent MCF-7 breast cancer cells inhibits cell growth in a dose- and time-dependent manner. Our results suggest that miR-206 could be a novel candidate for endocrine therapy that targets only ERα in breast cancer. [Cancer Res 2008;68(13):5004–8]
Serotonin Regulates Macrophage-Mediated Angiogenesis in a Mouse Model of Colon Cancer Allografts
Authors: Nocito Antonio , Dahm Felix , Jochum Wolfram , Jang Jae Hwi , Georgiev Panco , Bader Michael , Graf Rolf , Clavien Pierre-Alain 
Published: July 2008

AbstractSerotonin, a neurotransmitter with numerous functions in the central nervous system (CNS), is emerging as an important signaling molecule in biological processes outside of the CNS. Recent advances have implicated serotonin as a regulator of inflammation, proliferation, regeneration, and repair. The role of serotonin in tumor biology in vivo has not been elucidated. Using a genetic model of serotonin deficiency (Tph1−/−) in mice, we show serotonin to be crucial for the growth of s.c. colon cancer allografts in vivo. Serotonin does not enhance tumor cell proliferation but acts as a regulator of angiogenesis by reducing the expression of matrix metalloproteinase 12 (MMP-12) in tumor-infiltrating macrophages, entailing lower levels of angiostatin—an endogenous inhibitor of angiogenesis. Accordingly, serotonin deficiency causes slower growth of s.c. tumors by reducing vascularity, thus increasing hypoxia and spontaneous necrosis. The biological relevance of these effects is underscored by the reconstitution of serotonin synthesis in Tph1−/− mice, which restores allograft phenotype in all aspects. In conclusion, we show how serotonin regulates angiogenesis in s.c. colon cancer allografts by influencing MMP-12 expression in tumor-infiltrating macrophages, thereby affecting the production of circulating angiostatin. [Cancer Res 2008;68(13):5152–8]
NO Signaling Confers Cytoprotectivity through the Survivin Network in Ovarian Carcinomas
Authors: Engels Knut , Knauer Shirley K. , Loibl Sibylle , Fetz Verena , Harter Philipp , Schweitzer Andrea , Fisseler-Eckhoff Annette , Kommoss Friedrich , Hanker Lars , Nekljudova Valentina , Hermanns Iris , Kleinert Hartmut , Mann Wolf , du Bois Andreas , Stauber Roland H. 
Published: July 2008

Abstract
Despite considerable success in the treatment of epithelial ovarian cancer (EOC), therapy resistance counteracts improvement of long-term survival. The dual role of survivin as an apoptosis inhibitor and mitotic regulator has been associated with disease outcome. However, the molecular mechanisms involved in the deregulated expression in EOC of survivin need further investigation. Here, we show that high amounts of the nitric oxide (NO) donors, S-nitroso-N-acetyl-penicillamine (SNAP) and sodium nitroprusside (SNP) or strong overexpression of the inducible nitric oxide synthase (iNOS) suppressed survivin levels via the p38MAPK pathway and triggered apoptosis in ovarian cancer cell lines (OCC). Importantly, low NO concentrations conferred resistance against carboplatin/paclitaxel-induced apoptosis. Cytoprotection was mediated by survivin because we observed its up-regulation subsequent to low SNAP/SNP doses or ectopic expression of low amounts of iNOS. Also, RNAi-mediated depletion of survivin blocked the antiapoptotic effects of NO signaling. Induction of survivin involves activation of the phosphatidylinositol-3-kinase (PI3K)/Akt pathway, which was antagonized by the PI3K-inhibitor, LY294002. Interestingly, application of the iNOS-inhibitor 1400W together with RNAi-mediated survivin down-regulation cooperatively enhanced drug-induced apoptosis in OCCs. The iNOS/survivin interdependencies seem to be also of clinical relevance because immunohistochemistry revealed that low iNOS levels correlate with survivin expression (P &lt; 0.01) in carboplatin/paclitaxel-treated EOC patients with minimal postoperative residual tumor (n = 54). Also, iNOS and survivin expression were associated with increased risk for disease progression. Our study uncovers a novel molecular mechanism of how NO signaling may contribute to therapy resistance in EOC by modulating survivin expression. Pharmacogenetic iNOS/survivin-targeting strategies may hence be pursued to complement current treatment modalities in EOC. [Cancer Res 2008;68(13):5159–65]
The Warburg Effect in Leukemia-Stroma Cocultures Is Mediated by Mitochondrial Uncoupling Associated with Uncoupling Protein 2 Activation
Authors: Samudio Ismael , Fiegl Michael , McQueen Teresa , Clise-Dwyer Karen , Andreeff Michael 
Published: July 2008

Abstract
In 1956, Otto Warburg proposed that the origin of cancer cells was closely linked to a permanent respiratory defect that bypassed the Pasteur effect (i.e., the inhibition of anaerobic fermentation by oxygen). Since then, permanent defects in oxygen consumption that could explain the dependence of cancer cells on aerobic glycolysis have not been identified. Here, we show that under normoxic conditions exposure of leukemia cells to bone marrow–derived mesenchymal stromal cells (MSC) promotes accumulation of lactate in the culture medium and reduces mitochondrial membrane potential (ΔΨM) in both cell types. Notably, the consumption of glucose was not altered in cocultures, suggesting that the accumulation of lactate was the result of reduced pyruvate metabolism. Interestingly, the decrease in ΔΨM was mediated by mitochondrial uncoupling in leukemia cells and was accompanied by increased expression of uncoupling protein 2 (UCP2). HL60 cells fail to increase UCP2 expression, are not uncoupled after coculture, and do not exhibit increased aerobic glycolysis, whereas small interfering RNA–mediated suppression of UCP2 in OCI-AML3 cells reversed mitochondrial uncoupling and aerobic glycolysis elicited by MSC. Taken together, these data suggest that microenvironment activation of highly conserved mammalian UCPs may facilitate the Warburg effect in the absence of permanent respiratory impairment. [Cancer Res 2008;68(13):5198–205]
Splicing of a Novel Androgen Receptor Exon Generates a Constitutively Active Androgen Receptor that Mediates Prostate Cancer Therapy Resistance
Authors: Dehm Scott M. , Schmidt Lucy J. , Heemers Hannelore V. , Vessella Robert L. , Tindall Donald J. 
Published: July 2008

Abstract
The standard systemic treatment for prostate cancer (PCa) is androgen ablation, which causes tumor regression by inhibiting activity of the androgen receptor (AR). Invariably, PCa recurs with a fatal androgen-refractory phenotype. Importantly, the growth of androgen-refractory PCa remains dependent on the AR through various mechanisms of aberrant AR activation. Here, we studied the 22Rv1 PCa cell line, which was derived from a CWR22 xenograft that relapsed during androgen ablation. Three AR isoforms are expressed in 22Rv1 cells: a full-length version with duplicated exon 3 and two truncated versions lacking the COOH terminal domain (CTD). We found that CTD-truncated AR isoforms are encoded by mRNAs that have a novel exon 2b at their 3′ end. Functionally, these AR isoforms are constitutively active and promote the expression of endogenous AR-dependent genes, as well as the proliferation of 22Rv1 cells in a ligand-independent manner. AR mRNAs containing exon 2b and their protein products are expressed in commonly studied PCa cell lines. Moreover, exon 2b–derived species are enriched in xenograft-based models of therapy-resistant PCa. Together, our data describe a simple and effective mechanism by which PCa cells can synthesize a constitutively active AR and thus circumvent androgen ablation. [Cancer Res 2008;68(13):5469–77]
Synthesis and Anticancer Properties of Water-Soluble Zinc Ionophores
Authors: Magda Darren , Lecane Philip , Wang Zhong , Hu Weilin , Thiemann Patricia , Ma Xuan , Dranchak Patricia K. , Wang Xiaoming , Lynch Vincent , Wei Wenhao , Csokai Viktor , Hacia Joseph G. , Sessler Jonathan L. 
Published: July 2008

Abstract
Several water-solubilized versions of the zinc ionophore 1-hydroxypyridine-2-thione (ZnHPT), synthesized as part of the present study, have been found both to increase the intracellular concentrations of free zinc and to produce an antiproliferative activity in exponential phase A549 human lung cancer cultures. Gene expression profiles of A549 cultures treated with one of these water-soluble zinc ionophores, PCI-5002, reveal the activation of stress response pathways under the control of metal-responsive transcription factor 1 (MTF-1), hypoxia-inducible transcription factor 1 (HIF-1), and heat shock transcription factors. Additional oxidative stress response and apoptotic pathways were activated in cultures grown in zinc-supplemented media. We also show that these water-soluble zinc ionophores can be given to mice at 100 μmol/kg (300 μmol/m2) with no observable toxicity and inhibit the growth of A549 lung and PC3 prostate cancer cells grown in xenograft models. Gene expression profiles of tumor specimens harvested from mice 4 h after treatment confirmed the in vivo activation of MTF-1–responsive genes. Overall, we propose that water-solubilized zinc ionophores represent a potential new class of anticancer agents. [Cancer Res 2008;68(13):5318–25]
Pim Kinases Promote Cell Cycle Progression by Phosphorylating and Down-regulating p27Kip1 at the Transcriptional and Posttranscriptional Levels
Authors: Morishita Daisuke , Katayama Ryohei , Sekimizu Kazuhisa , Tsuruo Takashi , Fujita Naoya 
Published: July 2008

Abstract
The serine/threonine kinase Pim is known to promote cell cycle progression and to inhibit apoptosis leading to tumorigenesis. However, the precise mechanisms remain unclear. We show, herein, that all the Pim family members (Pim1, Pim2, and Pim3) bind to and directly phosphorylate the cyclin-dependent kinase inhibitor p27Kip1 at threonine-157 and threonine-198 residues in cells and in vitro. The Pim-mediated phosphorylation induced p27Kip1 binding to 14-3-3 protein, resulting in its nuclear export and proteasome-dependent degradation. Ectopic expression of Pim kinases overcome the G1 arrest mediated by wild-type p27Kip1 but not by phosphorylation-resistant T157A-p27Kip1 or T198A-p27Kip1. In addition to the posttranslational regulations, p27Kip1 promoter assay revealed that Pim kinases also had the ability to suppress p27Kip1 transcription. Pim-mediated phosphorylation and inactivation of forkhead transcription factors, FoxO1a and FoxO3a, was involved in the transcriptional repression of the p27Kip1 gene. In contrast, inhibition of Pim signaling by expressing the dominant-negative form of Pim1 increased nuclear p27Kip1 level and attenuated cell proliferation. Because the CDK inhibitor p27Kip1 plays a crucial role in tumor suppression by inhibiting abnormal cell cycle progression, Pim kinases promote cell cycle progression and tumorigenesis by down-regulating p27Kip1 expression at both transcriptional and posttranslational levels. [Cancer Res 2008;68(13):5076–85]
Frequent Detection of Merkel Cell Polyomavirus in Human Merkel Cell Carcinomas and Identification of a Unique Deletion in the VP1 Gene
Authors: Kassem Ahmad , Schöpflin Anja , Diaz Carlos , Weyers Wolfgang , Stickeler Elmar , Werner Martin , zur Hausen Axel 
Published: July 2008

Abstract
Merkel cell carcinoma (MCC) is a rare but very aggressive human malignancy of the elderly or immunosuppressed patients. Recently, the clonal integration of a new human polyoma virus, which was termed Merkel cell polyomavirus (MCPyV), has been reported in 8 of 10 MCC patients. In the present study, we studied the formalin-fixed and paraffin-embedded tissue specimens of 39 MCC for the presence of MCPyV by PCR. We applied four different primer sets directed against the large T antigen and the VP1 gene of MCPyV. We were able to detect MCPyV in 77% (n = 30) of MCC as confirmed by sequence analyses of the PCR products. Sequence analyses showed only minor nucleotide changes compared with the previously published MCC sequences. In addition, one patient revealed the amplification of two PCR products using PCR primers directed against the VP1 gene. Sequence analyses confirmed the presence of the expected 351-bp PCR product and in addition a second PCR product of 261 bp containing a unique 90-bp deletion in the VP1 gene, which will lead to a predicted loss of 28 amino acids. The unique 90-bp deletion within the VP1 gene possibly is a result of incomplete viral integration of MCPyV in the MCC. The presence of MCPyV in the majority of MCC tissue specimens in our study strongly underlines a possible role for MCPyV as an etiologic agent in the carcinogenesis of MCC. [Cancer Res 2008;68(13):5009–13]