bluuebunny/crossref_metadata_2025_split huggingface dataset:
Smad-Binding Defective Mutant of Transforming Growth Factor β Type I Receptor Enhances Tumorigenesis but Suppresses Metastasis of Breast Cancer Cell Lines
Authors: Tian Fang , Byfield Stacey DaCosta , Parks W. Tony , Stuelten Christina H. , Nemani Deepa , Zhang Ying E. , Roberts Anita B. 
Published: September 2005

Abstract
The role of transforming growth factor β (TGF-β) in carcinogenesis is complex, with tumor suppressor and pro-oncogenic activities depending on the particular tumor cell and its stage in malignant progression. We previously have demonstrated in breast cancer cell lines that Smad2/3 signaling played a dominant role in mediating tumor suppressor effects on well-differentiated breast cancer cell lines grown as xenografts and prometastatic effects on a more invasive, metastatic cell line. Our present data based on selective interference with activation of endogenous Smad2 and Smad3 by stable expression of a mutant form of the TGF-β type I receptor (RImL45) unable to bind Smad2/3 but with a functional kinase again show that reduction in Smad2/3 signaling by expression of RImL45 enhanced the malignancy of xenografted tumors of the well-differentiated MCF10A-derived tumor cell line MCF10CA1h, resulting in formation of larger tumors with a higher proliferative index and more malignant histologic features. In contrast, expression of RImL45 in the more aggressive MCF10CA1a cell line strongly suppressed formation of lung metastases following tail vein injection. These results suggest a causal, dominant role for the endogenous Smad2/3 signaling pathway in the tumor suppressor and prometastatic activities of TGF-β in these cells. Using an in vitro assay, we further show that non-Smad signaling pathways, including p38 and c-Jun NH2-terminal kinase, cooperate with TGF-β/Smads in enhancing migration of metastatic MCF10CA1a cells, but that, although necessary for migration, these other pathways are not sufficient for metastasis.
The Increased Expression of Peroxisome Proliferator-Activated Receptor-γ1 in Human Breast Cancer Is Mediated by Selective Promoter Usage
Authors: Wang Xin , Southard R. Chase , Kilgore Michael W. 
Published: September 2005

Abstract
Peroxisome proliferator-activated receptor-γ1 (PPARγ1) is transactivated by a wide range of ligands in normal human mammary epithelial and breast cancer cells. Although transactivation of PPARγ mediates the expression of genes that are markers of differentiation, its overexpression in cancers of the breast, thyroid, colon, and lung suggests its dysregulation may play a role in oncogenesis, cancer progression, or both. We report the overexpression of PPARγ is caused by the use of a tumor-specific promoter in breast cancer cells that is distinct from the promoter used in normal epithelia. Thus, the increase in PPARγ expression seen in breast cancer cells results from promoter recruitment, providing new insights into the expression and actions of PPARγ in breast cancer.
Spermine Acts as a Negative Regulator of Macrophage Differentiation in Human Myeloid Leukemia Cells
Authors: Gavin Igor M. , Glesne David , Zhao Yong , Kubera Cathryn , Huberman Eliezer 
Published: September 2005

AbstractThe role of putrescine, spermidine and spermine in phorbol 12-myristate-13-acetate (PMA)-induced macrophage differentiation was examined in human HL-60 and U-937 myeloid leukemia cells. Unlike other polyamines, spermine affected this differentiation by acting as a negative regulator. This negative regulation was established by showing that the PMA-induced macrophage phenotype, but not PMA-associated replication arrest, was abrogated (a) by replenishing the PMA-evoked decrease in cellular spermine levels with this polyamine from an exogenous source and (b) by blocking PMA-induced expression of the polyamine catabolic enzyme N1-spermidine/spermine acetyltransferase (SSAT) with antisense oligonucleotides in the presence of low substrate level. The PMA-evoked reduction in cellular spermine appears to result from an increase in the activity of SSAT and a decrease in the activity of ornithine decarboxylase, the polyamine biosynthetic enzyme. To a degree, these changes are due to corresponding changes in the expression of the genes that code for these enzymes. When cell differentiation is initiated, SSAT expression is increased after PMA-evoked activation of protein kinase C-β. The present studies raise the possibility that agents able to reduce spermine levels in patients’ myeloid leukemia cells may enhance the activity of differentiation therapy drugs for this type of leukemia.
Synergistic Activation of Innate Immunity by Double-Stranded RNA and CpG DNA Promotes Enhanced Antitumor Activity
Authors: Whitmore Mark M. , DeVeer Michael J. , Edling Andrea , Oates Rhonda K. , Simons Brenna , Lindner Daniel , Williams Bryan R. G. 
Published: September 2005

AbstractDouble-stranded RNA (dsRNA) and unmethylated CpG sequences in DNA are pathogen-associated molecular patterns of viruses and bacteria that activate innate immunity. To examine whether dsRNA and CpG DNA could combine to provide enhanced stimulation of innate immune cells, murine macrophages were stimulated with poly-rI:rC (pIC), a dsRNA analog, and CpG-containing oligodeoxynucleotides (CpG-ODN). Combined treatments demonstrated synergy in nitric oxide, interleukin (IL)-12, tumor necrosis factor α, and IL-6 production. Studies using neutralizing antibodies for type I interferons (IFNs), IFN-α and IFN-β, indicated that nitric oxide synthase synergism is mediated by paracrine/autocrine effects of IFN-β. In contrast, enhanced cytokine production occurred independent of type I IFN and was maintained in macrophages from IFN-α/β receptor knockout mice. Cotransfection of human Toll-like receptors 3 and 9 (receptors for dsRNA and CpG DNA, respectively) into 293T cells supported synergistic activation of an IL-8 promoter reporter construct by pIC, indicating interaction of the signaling pathways in driving the synergy response. In vivo stimulation of mice with pIC and CpG-ODN demonstrated synergy for serum IL-6 and IL-12p40 levels that correlated with an enhanced antitumor effect against established B16-F10 experimental pulmonary metastases. Treatment of tumor-bearing mice with pIC and CpG-ODN in combination resulted in enhanced nitric oxide synthase expression in lung tissue and enhanced up-regulation of class I major histocompatibility complex on splenic dendritic cells relative to treatments with either agent alone. In conclusion, the combined detection of viral pathogen-associated molecular patterns, i.e., dsRNA and CpG DNA, may mimic definitive viral recognition, resulting in an enhanced innate immune response that could be used for tumor vaccination or immunotherapy.
Therapeutic Effectiveness of Recombinant Cancer Vaccines Is Associated with a Prevalent T-Cell Receptor α Usage by Melanoma-specific CD8+ T Lymphocytes
Authors: De Palma Raffaele , Marigo Ilaria , Del Galdo Francesco , De Santo Carmela , Serafini Paolo , Cingarlini Sara , Tüting Thomas , Lenz Julia , Basso Giuseppe , Milan Gabriella , Zanovello Paola , Bronte Vincenzo 
Published: September 2005

Abstract
Definition of immune variables that correlate with the antitumor activity of cancer vaccines is critical for monitoring immunotherapy protocols. To define surrogate end points predictive of the therapeutic efficacy of recombinant vaccines based on melanoma antigen tyrosinase-related protein (TRP)-2, we evaluated several properties of antigen-specific CD8+ T lymphocytes in single mice undergoing either prophylactic or therapeutic immunization. Predictive markers for the efficacy of genetic vaccination were identified in the prophylactic model used. Interestingly, the number of tetramer+ CD8+ T lymphocytes expanded in vitro after a single cycle of stimulation with the immunodominant TRP-2 peptide was of the highest predictive value. In the therapeutic model, no variable examined at a single mouse level predicted the long-term therapeutic effect. Mice that survived did not show the highest expansion of antigen-specific lymphocytes or the more functionally active effectors, ex vivo or after in vitro culture with the peptide antigen. Successful therapy correlated strictly with the skewing of the T-cell receptor repertoire of tetramer-sorted, TRP-2–specific CD8+ T lymphocytes, which showed a preferential α chain usage with a common CDR3 region.
Integrin Fibronectin Receptors in Matrix Metalloproteinase-1–Dependent Invasion by Breast Cancer and Mammary Epithelial Cells
Authors: Jia Yifeng , Zeng Zhao-Zhu , Markwart Sonja M. , Rockwood Korrene F. , Ignatoski Kathleen M. Woods , Ethier Stephen P. , Livant Donna L. 
Published: September 2005

Abstract
Integrins contribute to progression in many cancers, including breast cancer. For example, the interaction of α5β1 with plasma fibronectin causes the constitutive invasiveness of human prostate cancer cells. Inhibition of this process reduces tumorigenesis and prevents metastasis and recurrence. In this study, naturally serum-free basement membranes were used as invasion substrates. Immunoassays were used to compare the roles of α5β1 and α4β1 fibronectin receptors in regulating matrix metalloproteinase (MMP)-1–dependent invasion by human breast cancer and mammary epithelial cells. We found that a peptide consisting of fibronectin PHSRN sequence, Ac-PHSRN-NH2, induces α5β1-mediated invasion of basement membranes in vitro by human breast cancer and mammary epithelial cells. PHSRN-induced invasion requires interstitial collagenase MMP-1 activity and is suppressed by an equimolar concentration of a peptide consisting of the LDV sequence of the fibronectin connecting segment, Ac-LHGPEILDVPST-NH2, in mammary epithelial cells, but not in breast cancer cells. This sequence interacts with α4β1, an integrin that is often down-regulated in breast cancer cells. Immunoblotting shows that the PHSRN peptide stimulates MMP-1 production by serum-free human breast cancer and mammary epithelial cells and that the LDV peptide represses PHSRN-stimulated MMP-1 production only in mammary epithelial cells. Furthermore, PHSRN stimulates MMP-1 activity in breast cancer cells and mammary epithelial cells with a time course that closely parallels invasion induction. Thus, down-regulation of surface α4β1 during oncogenic transformation may be crucial for establishment of the α5β1-induced, MMP-1–dependent invasive phenotype of breast cancer cells.
Vascular Normalization by Vascular Endothelial Growth Factor Receptor 2 Blockade Induces a Pressure Gradient Across the Vasculature and Improves Drug Penetration in Tumors
Authors: Tong Ricky T. , Boucher Yves , Kozin Sergey V. , Winkler Frank , Hicklin Daniel J. , Jain Rakesh K. 
Published: September 2005

Abstract
Elevated interstitial fluid pressure, a hallmark of solid tumors, can compromise the delivery of therapeutics to tumors. Here we show that blocking vascular endothelial growth factor (VEGF) signaling by DC101 (a VEGF-receptor-2 antibody) decreases interstitial fluid pressure, not by restoring lymphatic function, but by producing a morphologically and functionally “normalized” vascular network. We demonstrate that the normalization process prunes immature vessels and improves the integrity and function of the remaining vasculature by enhancing the perivascular cell and basement membrane coverage. We also show that DC101 induces a hydrostatic pressure gradient across the vascular wall, which leads to a deeper penetration of molecules into tumors. Thus, vascular normalization may contribute to the improved survival rates in tumor-bearing animals and in colorectal carcinoma patients treated with an anti-VEGF antibody in combination with cytotoxic therapies.
CpG Hypermethylation of
MDR1
Gene Contributes to the Pathogenesis and Progression of Human Prostate Cancer
Authors: Enokida Hideki , Shiina Hiroaki , Igawa Mikio , Ogishima Tatsuya , Kawakami Toshifumi , Bassett William W. , Anast Jason W. , Li Long-Cheng , Urakami Shinji , Terashima Masaharu , Verma Mukesh , Kawahara Motoshi , Nakagawa Masayuki , Kane Christopher J. , Carroll Peter R. , Dahiya Rajvir 
Published: September 2005

Abstract
Multidrug resistance 1 (MDR1) gene encodes for P-glycoprotein (P-gp), a Mr 170,000 transmembrane calcium-dependent efflux pump that is inactivated in prostate cancer. We hypothesize that inactivation of the MDR1 gene through CpG methylation contributes to the pathogenesis and progression of prostate cancer. To test this hypothesis, CpG methylation status of the MDR1 promoter and its correlation with clinicopathological findings were evaluated in 177 prostate cancer samples and 69 benign prostate hypertrophy (BPH) samples. Cellular proliferation index and apoptotic index were determined by proliferating cell nuclear antigen (PCNA) and single-strand DNA immunostaining, respectively. After 5-aza-2′-deoxycytidine treatment, increased expression of MDR1 mRNA transcript was found in prostate cancer cell lines (DU145, DuPro, and ND1). MDR1 methylation frequency was significantly higher in prostate cancer samples compared with BPH samples (54.8 versus 11.6%, respectively, P &lt; 0.001). Logistic regression analysis revealed that PC patients are 11.5 times more likely to have MDR1 methylation than BPH patients (95% confidence interval 4.87–27.0) and that MDR1 methylation is independent of the age. Significant correlation of MDR1 methylation was observed with high pT category (P &lt; 0.001), high Gleason sum (P = 0.008), high preoperative prostate-specific antigen (P = 0.01), and advancing pathological features. In addition, PCNA-labeling index were significantly higher in methylation-specific PCR (MSP)-positive than in MSP-negative prostate cancer samples (P = 0.048). In contrast, no significant difference in apoptotic index was found between MSP-positive and -negative prostate cancer samples. These findings suggest that CpG hypermethylation of MDR1 promoter is a frequent event in prostate cancer and is related to disease progression via increased cell proliferation in prostate cancer cells.
Silencing of the Hypoxia-Inducible Cell Death Protein BNIP3 in Pancreatic Cancer
Authors: Okami Jiro , Simeone Diane M. , Logsdon Craig D. 
Published: September 2005

Abstract
Hypoxic conditions exist within pancreatic adenocarcinoma, yet pancreatic cancer cells survive and replicate within this environment. To understand the mechanisms involved in pancreatic cancer adaptation to hypoxia, we analyzed expression of a regulator of hypoxia-induced cell death, Bcl-2/adenovirus E1B 19 kDa interacting protein 3 (BNIP3). We found that BNIP3 was down-regulated in nine of nine pancreatic adenocarcinomas compared with normal pancreas despite the up-regulation of other hypoxia-inducible genes, including glucose transporter-1 and insulin-like growth factor-binding protein 3. Also, BNIP3 expression was undetectable even after hypoxia treatment in six of seven pancreatic cancer cell lines. The BNIP3 promoter, which was remarkably activated by hypoxia, is located within a CpG island. The methylation status of CpG dinucleotides within the BNIP3 promoter was analyzed after bisulfite treatment by sequencing and methylation-specific PCR. Hypermethylation of the BNIP3 promoter was observed in all BNIP3-negative pancreatic cancer cell lines and eight of 10 pancreatic adenocarcinoma samples. Treatment of BNIP3-negative pancreatic cancer cell lines with a DNA methylation inhibitor, 5-aza-2′ deoxycytidine, restored hypoxia-induced BNIP3 expression. BNIP3 expression was also restored by introduction of a construct consisting of a full-length BNIP3 cDNA regulated by a cloned BNIP3 promoter. Restoration of BNIP3 expression rendered the pancreatic cancer cells notably more sensitive to hypoxia-induced cell death. In conclusion, down-regulation of BNIP3 by CpG methylation likely contributes to resistance to hypoxia-induced cell death in pancreatic cancer.
Proadrenomedullin NH2-Terminal 20 Peptide Is a Potent Angiogenic Factor, and Its Inhibition Results in Reduction of Tumor Growth
Authors: Martínez Alfredo , Zudaire Enrique , Portal-Núñez Sergio , Guédez Liliana , Libutti Steven K. , Stetler-Stevenson William G. , Cuttitta Frank 
Published: September 2005

Abstract
We have found through ex vivo and in vivo angiogenesis models that the adrenomedullin gene-related peptide, proadrenomedullin NH2-terminal 20 peptide (PAMP), exhibits a potent angiogenic potential at femtomolar concentrations, whereas classic angiogenic factors such as vascular endothelial growth factor and adrenomedullin mediate a comparable effect at nanomolar concentrations. We found that human microvascular endothelial cells express PAMP receptors and respond to exogenous addition of PAMP by increasing migration and cord formation. Exposure of endothelial cells to PAMP increases gene expression of other angiogenic factors such as adrenomedullin, vascular endothelial growth factor, basic fibroblast growth factor, and platelet-derived growth factor C. In addition, the peptide fragment PAMP(12-20) inhibits tumor cell–induced angiogenesis in vivo and reduces tumor growth in xenograft models. Together, our data demonstrate PAMP to be an extremely potent angiogenic factor and implicate this peptide as an attractive molecular target for angiogenesis-based antitumor therapy.
Cell-Type-Specific Responses to Chemotherapeutics in Breast Cancer
Authors: Troester Melissa A. , Hoadley Katherine A. , Sørlie Therese , Herbert Brittney-Shea , Børresen-Dale Anne-Lise , Lønning Per Eystein , Shay Jerry W. , Kaufmann William K. , Perou Charles M. 
Published: September 2005

AbstractRecent microarray studies have identified distinct subtypes of breast tumors that arise from different cell types and that show statistically significant differences in patient outcome. To gain insight into these differences, we identified in vitro and in vivo changes in gene expression induced by chemotherapeutics. We treated two cell lines derived from basal epithelium (immortalized human mammary epithelial cells) and two lines derived from luminal epithelium (MCF-7 and ZR-75–1) with chemotherapeutics used in the treatment of breast cancer and assayed for changes in gene expression using DNA microarrays. Treatment doses for doxorubicin and 5-fluorouracil were selected to cause comparable cytotoxicity across all four cell lines. The dominant expression response in each of the cell lines was a general stress response; however, distinct expression patterns were observed. Both cell types induced DNA damage-response genes such as p21waf1, but the response in the luminal cells showed higher fold changes and included more p53-regulated genes. Luminal cell lines repressed a large number of cell cycle-regulated genes and other genes involved in cellular proliferation, whereas the basal cell lines did not. Instead, the basal cell lines repressed genes that were involved in differentiation. These in vitro responses were compared with expression responses in breast tumors sampled before and after treatment with doxorubicin or 5-fluorouracil/mitomycin C. The in vivo data corroborated the cell-type-specific responses to chemotherapeutics observed in vitro, including the induction of p21waf1. Similarities between in vivo and in vitro responses help to identify important response mechanisms to chemotherapeutics.
Cytoplasmic Mislocalization of p27Kip1 Protein Is Associated with Constitutive Phosphorylation of Akt or Protein Kinase B and Poor Prognosis in Acute Myelogenous Leukemia
Authors: Min Yoo Hong , Cheong June-Won , Kim Ji Yeon , Eom Ju In , Lee Seung Tae , Hahn Jee Sook , Ko Yun Woong , Lee Mark Hong 
Published: September 2005

Abstract
Cyclin-dependent kinase inhibitor p27Kip1 functions at the nuclear level by binding to cyclin E/cyclin-dependent kinase-2. It was shown that Akt or protein kinase B (Akt/PKB)-dependent phosphorylation of p27Kip1 led to the cytoplasmic mislocalization of p27Kip1, suggesting the potential abrogation of its activity. Here, we evaluated the localization of p27Kip1 protein in leukemic blasts in relation to Akt/PKB phosphorylation and clinical outcomes in acute myelogenous leukemia (AML). Western blot analysis of the nuclear and cytoplasmic fractions revealed a heterogenous localization pattern of p27Kip1 in AML. Cytoplasmic mislocalization of p27Kip1 was significantly associated with the constitutive serine473 Akt/PKB phosphorylation in AML cells (P &lt; 0.05). Transfection of U937 cells with an expression construct encoding the constitutively active form of Akt/PKB resulted in a remarkable increase in the levels of cytoplasmic p27Kip1. Whereas the transfection of U937 cells with a construct encoding dominant-negative Akt/PKB resulted in a recovery of nuclear localization of p27Kip1. Both the disease-free survival and overall survival are significantly shorter in AML cases with high cytoplasmic to nuclear ratio of p27Kip1 localization compared with the cases with low cytoplasmic to nuclear ratio (P = 0.0353, P = 0.0023, respectively). Multivariate analysis indicated that the cytoplasmic to nuclear ratio of p27Kip1 localization was an independent prognostic variable for both disease-free survival and overall survival (P = 0.043, P = 0.008, respectively). These findings additionally extend our understanding of the role of p27Kip1 in AML, and buttress the case of p27Kip1 mislocalization as a prognostic indicator and Akt/PKB/p27Kip1 pathway as a ready target for antileukemia therapy.
Evaluation of Human Thymidine Kinase 1 Substrates as New Candidates for Boron Neutron Capture Therapy
Authors: Al-Madhoun Ashraf S. , Johnsamuel Jayaseharan , Barth Rolf F. , Tjarks Werner , Eriksson Staffan 
Published: September 2005

Abstract
Thymidine analogs containing o-carboranylalkyl groups at the 3-position were screened as potential substrates for human thymidine kinase 1 (TK1), an enzyme that is selectively expressed in a variety of rapidly proliferating cells, including tumor cells. On the basis of previous studies, 12 of these were identified as potential delivery agents for boron neutron capture therapy, a therapeutic method used for the treatment of high-grade brain tumors. Compound 4 with a pentylene spacer between the o-carborane cage and the thymidine scaffold and compound 10, which has an additional dihydroxypropyl substituent at the o-carborane cage, were the best substrates for TK1 with kcat/Km values of 27% and 36% relative to that of thymidine, respectively. These compounds showed partial competitive inhibition for thymidine phosphorylation by TK1. Neither compound was a substrate of recombinant human thymidine phosphorylase nor were their respective 5′-monophosphates substrates of 5′-deoxynucleotidase 1, thereby indicating potential in vivo stability. The octanol/water partition coefficient for compound 10 was 2.09, suggesting that it has excellent physiochemical properties for crossing the blood brain barrier and penetrating brain tissue. The in vitro cytotoxic effect of the 12 analogs was moderate to low in mammalian cell cultures with IC50 values between 10 and 160 μmol/L. Compounds 4 and 10 were taken up selectively and retained by the murine fibroblast L929 cell line, in contrast to its TK1-deficient variant. These findings suggest that compound 10 is a promising candidate for selective delivery of boron-10 to malignant cells, and additional in vivo studies are planned to evaluate it for boron neutron capture therapy of brain tumors.