bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cyclin dependent kinase inhibitor p27Kip1 is upregulated by hypoxia via an ARNT dependent pathway
Authors: Wang Gang , Reisdorph Richard , Clark Robert E. , Miskimins Robin , Lindahl Ronald , Miskimins W. Keith 
Published: September 2003

AbstractExpression of cyclin dependent kinase (Cdk) inhibitor p27Kip1, which blocks cell cycle progression from G1 to S phase, can be regulated via multiple mechanisms including transcription, protein degradation, and translation. Recently, it was shown that p27Kip1 plays an important role in the cellular response to hypoxia. However, the mechanisms involved in the hypoxia‐induced regulation of p27Kip1 expression are still not clear. In this study, we compare the expression of p27Kip1 in two related murine hepatoma cell lines, Hepa‐1 and c4. Hepa‐1 produces functional aryl hydrocarbon receptor nuclear translocator (ARNT). c4 cells are derived from Hepa‐1, but are ARNT deficient. Interestingly, we observed cell line‐dependent effects of hypoxia on the expression of p27Kip1. The level of p27Kip1 protein in Hepa‐1 cells is enhanced by hypoxia, but is reduced by hypoxia in c4 cells. Further investigation demonstrated that hypoxia‐induced, ARNT‐mediated, transactivation of the p27Kip1 gene in Hepa‐1 cells is responsible for the increase in p27Kip1 protein. Once c4 cells were stably transfected with the wild type ARNT gene, a hypoxia‐induced increase in p27Kip1 mRNA was observed and reduction of p27Kip1 protein caused by hypoxia was blocked. Hence, our data indicate that ARNT is involved in transcriptional upregulation of the p27Kip1 gene under hypoxic conditions. © 2003 Wiley‐Liss, Inc.
Imaging gene expression using oligonucleotides and peptide nucleic acids
Authors: Paroo Zain , Corey David R. 
Published: September 2003

AbstractThe development of methods for non‐invasive, real‐time imaging of gene expression would provide powerful tools for biomedical research and medical diagnostics. A broadly applicable strategy for achieving this goal is the use of complementary oligonucleotide probes for recognition of mRNA. The major challenge for molecular imaging is the development of specific and efficient transducers for signaling probe–target interaction. This review summarizes the strengths and limitations of reported molecular approaches for imaging of mRNA expression and discusses the challenges to development of in vivo methods. © 2003 Wiley‐Liss, Inc.
Optical imaging and tumor angiogenesis
Authors: Lin Pengnain Charles 
Published: September 2003

AbstractTumor angiogenesis is essential for tumor growth and progression. Therefore, targeting tumor blood vessels is a promising approach for cancer therapy. Angiogenesis, the formation of blood vessels, is a multistep process, and strongly influenced by the microenvironment. There are no in vitro assays that can resemble this dynamic process in vivo. For this reason, animal models and imaging technologies are critical for studying tumor angiogenesis, identifying therapeutic targets as well as validating the targets. Non‐invasive molecular imaging in animal models presents an unprecedented opportunity and ability for us to perform repetitive observations and analysis of the biological processes underlying tumor angiogenesis and tumor progression in living animals in real time. As we gain a better understanding of the fundamental molecular nature of cancer, these techniques will be an important adjunct in translating the knowledge into clinical practice. This important information may elucidate how the tumor blood vessels behave and respond to certain treatments and therapies. © 2003 Wiley‐Liss, Inc.
Tunable, monochromatic X‐rays: An enabling technology for molecular/cellular imaging and therapy
Authors: Carroll Frank 
Published: September 2003

AbstractPulsed, tunable, monochromatic X‐rays hold great potential as a cellular and molecular probe. These beams can be tuned to the binding energy of orbital electrons in atoms, making them extremely useful in diagnostic k‐edge imaging and Auger cascade radiotherapy. Their wide tunability makes them ideal for the performance of various techniques as disparate as protein crystallography and three‐dimensional, compressionless, monochromatic mammography. Since only the frequency best suited to the task at hand is used, radiation exposure to patients or animals is exceedingly low when compared to standard X‐ray techniques. © 2003 Wiley‐Liss, Inc.
Combinatorial discovery of tumor targeting peptides using phage display
Authors: Landon Linda A. , Deutscher Susan L. 
Published: September 2003

AbstractPeptides possess appropriate pharmacokinetic properties to serve as cancer imaging or therapeutic targeting agents. Currently, only a small number of rationally‐derived, labeled peptide analogues that target only a limited subset of antigens are available. Thus, finding new cancer targeting peptides is a central goal in the field of molecular targeting. Novel tumor‐avid peptides can be efficiently identified via affinity selections using complex random peptide libraries containing millions of peptides that are displayed on bacteriophage. In vitro and in situ affinity selections may be used to identify peptides with high affinity for the target antigen in vitro. Unfortunately, it has been found that peptides selected in vitro or in situ may not effectively target tumors in vivo due to poor peptide stability and other problems. To improve in vivo targeting, methodological combinatorial chemistry innovations allow selections to be conducted in the environment of the whole animal. Thus, new targeting peptides with optimal in vivo properties can be selected in vivo in tumor‐bearing animals. In vivo selections have been proven successful in identifying peptides that target the vasculature of specific organs. In addition, in vivo selections have identified peptides that bind specifically to the surface of or are internalized into tumor cells. In the future, direct selection of peptides for cancer imaging may be expedited using genetically engineered bacteriophage libraries that encode peptides with intrinsic radiometal‐chelation or fluorescent sequences. © 2003 Wiley‐Liss, Inc.
Molecular imaging: The latest generation of contrast agents and tissue characterization techniques
Authors: Blankenberg Francis G. 
Published: September 2003

AbstractMolecular Imaging technologies will have a profound impact on both basic research and clinical imaging in the near future. As the field covers many different specialties and scientific disciplines it is not possible to review all in a single article. In the current article we will turn our attention to those modalities that are either currently in use or in development for the medical imaging clinic. © 2003 Wiley‐Liss, Inc.
Molecular imaging in prostate cancer
Authors: Karam Jose A. , Mason Ralph P. , Koeneman Kenneth S. , Antich Peter P. , Benaim Elie A. , Hsieh Jer‐Tsong 
Published: September 2003

AbstractProstate cancer (PCa) is the most common non‐cutaneous malignancy in men. New ways to diagnose this cancer in its early stages are needed. Unique genetic and biochemical changes in the cell pave the way for tumors to grow and metastasize. Novel imaging approaches attempt to detect pathological processes in cancer cells at the molecular level. This has led to the establishment and development of the field of molecular imaging. Positron emission tomography (PET), magnetic resonance spectroscopic imaging (MRSI), magnetic resonance imaging (MRI), and radiolabeled antibodies are a few of the modalities that can detect abnormal tumor metabolic processes in the clinical setting. Other imaging techniques are still in their early phase of development but hold promise for the future, including bioluminescence imaging (BLI), measurement of tumor oxygenation, and measurement of uptake of iodine by tumors. These techniques are non‐invasive and can spare the patient undue morbidity, while potentially providing early diagnosis, accurate follow‐up and, finally, valuable prognostic information. © 2003 Wiley‐Liss, Inc.
Antisense imaging: And miles to go before we sleep?
Authors: Lewis Michael R. , Jia Fang 
Published: September 2003

AbstractLabeled oligonucleotide analogues for antisense imaging of messenger RNA (mRNA) have great potential for detection of endogenous gene expression in vivo. Successful antisense imaging may be useful for detecting cellular gene expression patterns and early molecular changes in disease. Conclusive demonstration of this technique has been hindered by formidable challenges in surmounting biological barriers and detecting low concentrations of target mRNA. Recent advances in the development of novel antisense molecules, high specific activity radiolabeling chemistry, sophisticated drug targeting technology, and complementary molecular imaging modalities make it quite possible that true antisense imaging will be realized in the near future. © 2003 Wiley‐Liss, Inc.
Functional imaging of angiogenesis in an orthotopic model of pancreatic cancer
Authors: Fleming Jason B. , Brekken Rolf A. 
Published: September 2003

AbstractPancreatic cancer is a major unsolved health problem. The estimated overall 5‐year survival rate of only 1–4% is due to aggressiveness of the disease and the lack of effective systemic therapies. Most pancreatic cancer‐related deaths are due to the development of metastases, which represents the culmination of a complex interaction between the host organism and neoplastic cells within the primary tumor. Therefore, the study of tumor–host interaction in the context of the whole organism is necessary to evaluate the pathogenesis of tumor growth and metastasis so that effective therapies can be developed. Recent advances in functional imaging combined with animal models that faithfully recreate the biology of human tumors have elevated our ability to examine these complex interactions. In this review, we will use the example of orthotopic mouse models of pancreatic cancer as a tool to survey the challenges and possibilities of functional imaging of angiogenesis, a critical determinant of metastasis. © 2003 Wiley‐Liss, Inc.
ErbB2 and EGFR are downmodulated during the differentiation of 3T3‐L1 preadipocytes
Authors: Pagano Eleonora , Calvo Juan Carlos 
Published: September 2003

AbstractThe expression of receptors belonging to the epidermal growth factor receptor subfamily has been largely studied these last years in epithelial cells mainly as involved in cell proliferation and malignant progression. Although much work has focused on the role of these growth factor receptors in the differentiation of a variety of tissues, there is little information in regards to normal stromal cells. We investigated erbB2 expression in the murine fibroblast cell line Swiss 3T3L1, which naturally or hormonally induced undergoes adipocyte differentiation. We found that the Swiss 3T3‐L1 fibroblasts express erbB2, in addition to EGFR, and in a quantity comparable to or even greater than the breast cancer cell line T47D. Proliferating cells increased erbB2 and EGFR levels when reaching confluence up to 4‐ and 10‐fold, respectively. This expression showed a significant decrease when growth‐arrested cells were stimulated to differentiate with dexamethasone and isobutyl‐methylxanthine. Differentiated cells presented a decreased expression of both erbB2 and EGFR regardless of whether the cells were hormonally or spontaneously differentiated. EGF stimulation of serum‐starved cells increased erbB2 tyrosine phosphorylation and retarded erbB2 migration in SDS–PAGE, suggesting receptor association and activation. Heregulin‐α1 and ‐β1, two EGF related factors, had no effect on erbB2 or EGFR phosphorylation. Although 3T3‐L1 cells expressed heregulin, its specific receptors, erbB3 and erbB4, were not found. This is the first time in which erbB2 is reported to be expressed in an adipocytic cell line which does not depend on non EGF family growth factors (thyroid hormone, growth hormone, etc.) to accomplish adipose differentiation. Since erbB2 and EGFR expression were downmodulated as differentiation progressed it is conceivable that a mechanism of switching from a mitogenic to a differentiating signaling pathway may be involved, through regulation of the expression of these growth factor receptors. © 2003 Wiley‐Liss, Inc.
Hpr6.6 protein mediates cell death from oxidative damage in MCF‐7 human breast cancer cells
Authors: Hand Randal A. , Craven Rolf J. 
Published: September 2003

AbstractReactive oxygen species (ROS) cause cell death and are associated with a variety of maladies, from trauma and infection to organ degeneration and cancer. Cells mount a complex response to oxidative damage that includes signaling from transmembrane receptors and intracellular kinases. We have analyzed the response to oxidative damage in human breast cancer cells expressing the Hpr6.6 (human membrane progesterone receptor) protein. Although Hpr6.6 is related to a putative progesterone‐binding protein, Hpr6.6 is widely expressed in epithelial tissues and shares close homology with a budding yeast damage response protein called Dap1p (damage response protein related to membrane progesterone receptor). We report here that the Hpr6.6 protein regulates the response to oxidative damage in breast cancer cells. Expression of Hpr6.6 in MCF‐7 cells sensitized the cells to death following long‐term/low dose or short‐term/high dose treatment with hydrogen peroxide. Cell death did not occur through a typical apoptotic mechanism and corresponded with hyperphosphorylation of the Akt and IκB proteins. However, inhibition of Akt activation and IκB degradation had no effect on Hpr6.6‐mediated cell death, suggesting that Hpr6.6 regulates cell death through a novel oxidative damage response pathway. Our work indicates a key regulatory function for Hpr6.6 in epithelial tissues exposed to oxidative damage. © 2003 Wiley‐Liss, Inc.
Modification of phospholipids fatty acid composition in reuber H35 hepatoma cells: Effect on HMG‐CoA reductase activity
Authors: García‐Pelayo M. Carmen , García‐Peregrín Eduardo , Martínez‐Cayuela Marina 
Published: September 2003

AbstractThere is controversy about the effect of saturated and polyunsaturated fats on 3‐hydroxy‐3‐methylglutaryl‐CoA (HMG‐CoA) reductase, the main regulatory enzyme of cholesterogenic pathway. Results from dietary studies are difficult to interpret because diets normally contain a mixture of fatty acids. Therefore, we have used Reuber H35 hepatoma cells whose phospholipids were enriched in different individual fatty acids and have studied their effects on the cellular reductase activity. Lauric, myristic, eicosapentaenoic (EPA), and docosahexaenoic (DHA) acids were supplemented to the culture medium coupled to bovine serum albumin. The four fatty acids were incorporated into phospholipids from cells grown in media containing whole serum or lipoprotein‐poor serum (LPPS). Reductase activity of cells cultivated in a medium with LPPS was three to four times higher than those cultivated in medium with whole serum. Saturated fatty acids increased reductase activity of cells grown in medium with whole serum, whereas n‐3 polyunsaturated fatty acids (PUFA) decreased it. However, both saturated and polyunsaturated fatty acids increased reductase activity when serum lipoproteins were removed. In conclusion, this is one of the first reports demonstrating that saturated and n‐3 PUFA only show differential effects on HMG‐CoA reductase activity in the presence of lipoproteins. © 2003 Wiley‐Liss, Inc.
Two alanines juxtaposed to aggrecan's G1 domain alter its intracellular localization
Authors: Oliver Bonnie L. , Cronin Chunxia G. , Bue Catherine , Hand Arthur R. , Tanzer Marvin L. 
Published: September 2003

AbstractNascent proteins translated and processed in the endoplasmic reticulum (ER) sometimes contain intrinsic signals for ER retention or ER retrieval. These signals are usually a few amino acids in length, and if alanine modifications are made within these sequences, normal transit patterns of the nascent protein frequently change. The purpose of this study was to determine whether two alanines juxtaposed to the first globular domain of aggrecan's core protein affect its transit in Chinese hamster ovary (CHO) cells. Results show that two alanines juxtaposed to the first globular domain (G1AA) minimized secretion of the protein. However, transgenic proteins with juxtaposed glutamate–phenylalanine (G1EF) or no additional amino acids (G1) were still secreted. GFP‐tagged G1AA localized in the lumen of the ER but not in the Golgi. In contrast, a portion of GFP‐tagged G1EF and G1 did appear in the Golgi compartment. More importantly, unique and striking accumulations of G1EF and G1 transgenic proteins were seen in large dilated regions of the ER cisternae, reminiscent of accumulations seen in α1‐antitrypsin deficiency disease. G1AA transgenic proteins did not form these vesicles but were diffusely distributed throughout the ER lumen. These results indicate that just two juxtaposed alanines can profoundly affect a large globular protein's intracellular localization. © 2003 Wiley‐Liss, Inc.
Overexpression of regucalcin modulates tumor‐related gene expression in cloned rat hepatoma H4‐II‐E cells
Authors: Tsurusaki Yoshinori , Yamaguchi Masayoshi 
Published: September 2003

AbstractRegucalcin is a regulatory protein in intracellular signaling pathway which is related to various protein kinases and protein phosphatases in many cells. The effect of regucalcin on the expression of tumor‐related genes was investigated in the cloned rat hepatoma H4‐II‐E cells and the hepatoma cells (transfectants) overexpressing regucalcin. Hepatoma cells were cultured for 24–72 h in the presence of fetal bovine serum (FBS; 10%). The proliferation of hepatoma cells was significantly suppressed at 24–72 h of culture in regucalcin transfectants as compared with that of wild‐type or mock‐type cells. Western blot analysis showed that regucalcin was markedly expressed in transfectants. The expression of c‐myc, c‐fos, c‐jun, Ha‐ras, and p53 mRNAs was determined using reverse transcription‐polymerase chain reaction (RT‐PCR). Of these genes, the expression of c‐myc or Ha‐ras mRNAs was significantly suppressed in regucalcin transfectants. The suppression of c‐myc mRNA expression in transfectants was confirmed by using Northern blot analysis; significant suppression was seen at 24, 48, or 72 h of culture in the presence of 10% FBS. Culture with 10% FBS significantly enhanced c‐myc mRNA expression in the hepatoma cells (wild‐type) as compared with that of 1% FBS. The enhancement was significantly abolished in the transfectants. Meanwhile, the expression of p53 mRNA in the hepatoma cells was significantly enhanced in regucalcin‐overexpressing hepatoma cells. This study demonstrates that the expression of oncogene c‐myc and Ha‐ras mRNA in hepatoma cells overexpressing regucalcin is suppressed, and that the tumor suppression gene p53 is enhanced in the transfectants. © 2003 Wiley‐Liss, Inc.
Sodium arsenite downregulates transcriptional activity of AP‐1 and CRE binding proteins in IL‐1β‐treated Caco‐2 cells by increasing the expression of the transcriptional repressor CREMα
Authors: Hershko Dan D. , Robb Bruce W. , Luo Guang‐jo , Hungness Eric S. , Hasselgren Per‐Olof 
Published: September 2003

AbstractIn recent studies, sodium arsenite (SA) inhibited IL‐6 production in cultured intestinal epithelial cells, at least in part by downregulating the activity of nuclear factor‐kappaB (NF‐κB). The influence of SA on the activity of other transcription factors regulating the interleukin‐6 (IL‐6) gene in enterocytes is not known. We tested the effect of SA on the activity of CCAAT/enhancer binding protein (C/EBP), activating protein‐1 (AP‐1), and CRE binding proteins in IL‐1β‐treated Caco‐2 cells. DNA binding activity was determined by electrophoretic mobility shift assay (EMSA) and transcriptional activity by transfecting cells with luciferase reporter plasmids containing promoter constructs with binding sites for the individual transcription factors. DNA binding activity for all three transcription factors was increased after treatment with SA or IL‐1β. In contrast, SA inhibited transcriptional activity of AP‐1 and CRE binding proteins but not C/EBP. Additional experiments provided evidence that the inhibition of AP‐1 and CRE mediated transcriptional activity was associated with, and probably caused by, increased expression of the transcriptional repressor cyclic AMP response element modulator (CREM)α. The present results are consistent with the concept that SA inhibits IL‐6 production in stimulated enterocytes by downregulating the transcriptional activity of several, but not all, IL‐6‐related transcription factors. Because of the multiple important biological functions of IL‐6 in the enterocyte and gut mucosa, methods to regulate enterocyte IL‐6 production have significant clinical implications. © 2003 Wiley‐Liss, Inc.
Analysis of SOX10 mutations identified in Waardenburg‐Hirschsprung patients: Differential effects on target gene regulation
Authors: Chan Kwok Keung , Wong Corinne Kung Yen , Lui Vincent Chi Hang , Tam Paul Kwong Hang , Sham Mai Har 
Published: September 2003

AbstractSOX10 is a member of the SOX gene family related by homology to the high‐mobility group (HMG) box region of the testis‐determining gene SRY. Mutations of the transcription factor gene SOX10 lead to Waardenburg‐Hirschsprung syndrome (Waardenburg‐Shah syndrome, WS4) in humans. A number of SOX10 mutations have been identified in WS4 patients who suffer from different extents of intestinal aganglionosis, pigmentation, and hearing abnormalities. Some patients also exhibit signs of myelination deficiency in the central and peripheral nervous systems. Although the molecular bases for the wide range of symptoms displayed by the patients are still not clearly understood, a few target genes for SOX10 have been identified. We have analyzed the impact of six different SOX10 mutations on the activation of SOX10 target genes by yeast one‐hybrid and mammalian cell transfection assays. To investigate the transactivation activities of the mutant proteins, three different SOX target binding sites were introduced into luciferase reporter gene constructs and examined in our series of transfection assays: consensus HMG domain protein binding sites; SOX10 binding sites identified in the RET promoter; and Sox10 binding sites identified in the P0 promoter. We found that the same mutation could have different transactivation activities when tested with different target binding sites and in different cell lines. The differential transactivation activities of the SOX10 mutants appeared to correlate with the intestinal and/or neurological symptoms presented in the patients. Among the six mutant SOX10 proteins tested, much reduced transactivation activities were observed when tested on the SOX10 binding sites from the RET promoter. Of the two similar mutations X467K and 1400del12, only the 1400del12 mutant protein exhibited an increase of transactivation through the P0 promoter. While the lack of normal SOX10 mediated activation of RET transcription may lead to intestinal aganglionosis, overexpression of genes coding for structural myelin proteins such as P0 due to mutant SOX10 may explain the dysmyelination phenotype observed in the patients with an additional neurological disorder. © 2003 Wiley‐Liss, Inc.