bluuebunny/crossref_metadata_2025 huggingface dataset:
Transcriptome-based identification of pro- and antioxidative gene expression in kidney cortex of nitric oxide-depleted rats
Authors: Wesseling Sebastiaan , Joles Jaap A. , van Goor Harry , Bluyssen Hans A. , Kemmeren Patrick , Holstege Frank C. , Koomans Hein A. , Braam Branko
Published: October 2006

Nitric oxide (NO) depletion in rats induces severe endothelial dysfunction within 4 days. Subsequently, hypertension and renal injury develop, which are ameliorated by α-tocopherol (VitE) cotreatment. The hypothesis of the present study was that NO synthase (NOS) inhibition induces a renal cortical antioxidative transcriptional response and invokes pro-oxidative and proinflammatory gene expression due to elimination of dampening effects of NO and enhanced oxidative stress. Male Sprague-Dawley rats received NOS inhibitor Nω-nitro-l-arginine (l-NNA, 500 mg/l water) for 4 (4d-LNNA), 21 (21d-LNNA), or 21 days with VitE in chow (0.7 g/kg body wt/day). Renal cortical RNA was applied to oligonucleotide rat arrays. In 4d-LNNA, 21d-LNNA, and 21d-LNNA+VitE, 120, 320, and 184 genes were differentially expressed, respectively. Genes related to glutathione and bilirubin synthesis were suppressed during 4d and 21d-LNNA and not corrected by VitE. Proteinuria, tubulointerstitial macrophages, and heme-oxygenase-1 (HO-1) expression were strongly correlated. Remarkably, pro-oxidative genes were not induced. Inflammation- and injury-related genes, including kidney injury molecule-1 and osteopontin, were unchanged at day 4, induced at 21d, and partly corrected by VitE. Superimposing HO-1 inhibition on NOS inhibition had no impact on the development of hypertension. To summarize, renal expression of genes involved in synthesis of the antioxidants glutathione and bilirubin seemed directly NO dependent, but there were no direct effects of NO depletion on pro-oxidant systems. This indicates that renal transcriptional regulation of two defense systems, glutathione and bilirubin syntheses, seems to depend upon adequate NO synthesis. Interaction between NO synthesis and heme degradation pathways for blood pressure regulation was not found.
Protein Disulfide Isomerase Expression Is Related to the Invasive Properties of Malignant Glioma
Authors: Goplen Dorota , Wang Jian , Enger Per Ø. , Tysnes Berit B. , Terzis A.J.A. , Laerum Ole D. , Bjerkvig Rolf
Published: October 2006

By serial transplantation of human glioblastoma biopsies into the brain of immunodeficient nude rats, two different tumor phenotypes were obtained. Initially, the transplanted xenografts displayed a highly invasive phenotype that showed no signs of angiogenesis. By serial transplantation in animals, the tumors changed to a less invasive, predominantly angiogenic phenotype. To identify novel proteins related to the invasive phenotype, the xenografts were analyzed using a global proteomics approach. One of the identified proteins was protein disulfide isomerase (PDI) A6 precursor. PDI is a chaperone protein that mediates integrin-dependent cell adhesion. It is both present in the cytosol and at the cell surface. We show that PDI is strongly expressed on invasive glioma cells, in both xenografts and at the invasive front of human glioblastomas. Using an in vitro migration assay, we also show that PDI is expressed on migrating glioma cells. To determine the functional significance of PDI in cell migration, we tested the effect of a PDI inhibitor, bacitracin, and a PDI monoclonal antibody on glioma cell migration and invasion in vitro. Both tumor spheroids derived from human glioblastoma xenografts in nude rat brain and cell line spheroids were used. The PDI antibody, as well as bacitracin, inhibited tumor cell migration and invasion. The anti-invasive effect of bacitracin was reversible after withdrawal of the inhibitor, indicating a specific, nontoxic effect. In conclusion, using a global proteomics approach, PDI was identified to play an important role in glioma cell invasion, and its action was effectively inhibited by bacitracin. (Cancer Res 2006; 66(20): 9895-902)
RET Is Constitutively Activated by Novel Tandem Mutations that Alter the Active Site Resulting in Multiple Endocrine Neoplasia Type 2B
Authors: Cranston Aaron N. , Carniti Cristiana , Oakhill Kim , Radzio-Andzelm Elzbieta , Stone Eric A. , McCallion Andrew S. , Hodgson Shirley , Clarke Sue , Mondellini Piera , Leyland Jean , Pierotti Marco A. , Whittaker Joanne , Taylor Susan S. , Bongarzone Italia , Ponder Bruce A.J.
Published: October 2006

Constitutive activation of the RET receptor tyrosine kinase underlies the genesis and progression of multiple endocrine neoplasia type 2 (MEN 2), a dominantly inherited cancer predisposition. Importantly, although kinase activation represents a common theme in neoplasias, not all activating mutations are functionally equivalent. Consistent with this, we ascertained a patient with classical features of MEN 2B, but lacking either of the classical mutations in RET (M918T or A883F). Instead, the patient harbors a novel pair of germ line missense mutations in cis at codons 804 and 805. We evaluated the potential physiochemical effects of these substitutions in silico, predicting both to be moderately deleterious in isolation, but severely deleterious in combination. Consistent with this postulate, we show that the identified tandem mutations (V804M/E805K) are biologically active, transforming cells in culture and that their transforming capacity in combination is distinctly synergistic. Furthermore, the V804M/E805K tandem lesion confers resistance to the small molecule receptor tyrosine kinase inhibitor, PP1, suggesting a mode of action distinct from that known for classical MEN 2B mutations. To address this question, we used homology molecular modeling in silico to model the active site of RET. We predict that RET804 constitutes a critical gatekeeper residue that, when mutated in combination with RET805, induces a conformational change in the hinge region that locks the active site in a position permissive for ATP hydrolysis. Our findings have implications both in the clinic and in the successful development of novel kinase-targeted anticancer drugs. (Cancer Res 2006; 66(20): 10179-87)
Transforming Growth Factor β Receptor Type II Inactivation Induces the Malignant Transformation of Intestinal Neoplasms Initiated by Apc Mutation
Authors: Muñoz Nina M. , Upton Melissa , Rojas Andres , Washington M. Kay , Lin Li , Chytil Anna , Sozmen Elif G. , Madison Blair B. , Pozzi Ambra , Moon Randall T. , Moses Harold L. , Grady William M.
Published: October 2006

The transforming growth factor-β (TGF-β) signaling pathway is a tumor-suppressor pathway that is commonly inactivated in colon cancer. TGF-β is a secreted ligand that mediates its effects through a transmembrane heteromeric receptor complex, which consists of type I (TGFBR1) and type II subunits (TGFBR2). Approximately 30% of colon cancers carry TGFBR2 mutations, demonstrating that it is a common target for mutational inactivation in this cancer. To assess the functional role of TGFBR2 inactivation in the multistep progression sequence of colon cancer, we generated a mouse model that recapitulates two common genetic events observed in human colon cancer by mating Apc1638N/wt mice with mice that are null for Tgfbr2 in the intestinal epithelium, Villin-Cre;Tgfbr2E2flx/E2flx mice. In this model, we observed a dramatic increase in the number of intestinal adenocarcinomas in the Apc1638N/wt;Villin-Cre;Tgfbr2E2flx/E2flx mice (called Apc1638N/wt;Tgfbr2IEKO) compared with those mice with intact Tgfbr2 (Apc1638N/wt;Tgfbr2E2flx/E2flx). Additionally, in vitro analyses of epithelial tumor cells derived from the Apc1638N/wt;Tgfbr2IEKO mice showed enhanced expression and activity of matrix metalloproteinase MMP-2 and MMP-9, as well as increased TGF-β1 secretion in the conditioned medium. Similarly, primary tumor tissues from the Apc1638N/wt;Tgfbr2IEKO mice also showed elevated amounts of TGF-β1 as well as higher MMP-2 activity in comparison with Apc1638N/wt;Tgfbr2E2flx/E2flx–derived tumors. Thus, loss of TGFBR2 in intestinal epithelial cells promotes the invasion and malignant transformation of tumors initiated by Apc mutation, providing evidence that Wnt signaling deregulation and TGF-β signaling inactivation cooperate to drive the initiation and progression, respectively, of intestinal cancers in vivo. (Cancer Res 2006; 66(20): 9837-44)
Caveolin-1 (CAV1) Is a Target of EWS/FLI-1 and a Key Determinant of the Oncogenic Phenotype and Tumorigenicity of Ewing's Sarcoma Cells
Authors: Tirado Oscar M. , Mateo-Lozano Silvia , Villar Joaquín , Dettin Luis E. , Llort Anna , Gallego Soledad , Ban Jozef , Kovar Heinrich , Notario Vicente
Published: October 2006

Tumors of the Ewing's sarcoma family (ESFT), such as Ewing's sarcoma (EWS) and primitive neuroectodermal tumors (PNET), are highly aggressive malignancies predominantly affecting children and young adults. ESFT express chimeric transcription factors encoded by hybrid genes fusing the EWS gene with several ETS genes, most commonly FLI-1. EWS/FLI-1 proteins are responsible for the malignant phenotype of ESFT, but only few of their transcriptional targets are known. Using antisense and short hairpin RNA–mediated gene expression knockdown, array analyses, chromatin immunoprecipitation methods, and reexpression studies, we show that caveolin-1 (CAV1) is a new direct target of EWS/FLI-1 that is overexpressed in ESFT cell lines and tumor specimens and is necessary for ESFT tumorigenesis. CAV1 knockdown led to up-regulation of Snail and the concomitant loss of E-cadherin expression. Consistently, loss of CAV1 expression inhibited the anchorage-independent growth of EWS cells and markedly reduced the growth of EWS cell–derived tumors in nude mice xenografts, indicating that CAV1 promotes the malignant phenotype in EWS carcinogenesis. Reexpression of CAV1 or E-cadherin in CAV1 knockdown EWS cells rescued the oncogenic phenotype of the original EWS cells, showing that the CAV1/Snail/E-cadherin pathway plays a central role in the expression of the oncogenic transformation functions of EWS/FLI-1. Overall, these data identify CAV1 as a key determinant of the tumorigenicity of ESFT and imply that targeting CAV1 may allow the development of new molecular therapeutic strategies for ESFT patients. (Cancer Res 2006; 66(20): 9937-47)
Comparative Proteomic Profiles of Meningioma Subtypes
Authors: Okamoto Hiroaki , Li Jie , Vortmeyer Alexander O. , Jaffe Howard , Lee Youn-Soo , Gläsker Sven , Sohn Tae-Sung , Zeng Weifen , Ikejiri Barbara , Proescholdt Martin A. , Mayer Christina , Weil Robert J. , Oldfield Edward H. , Zhuang Zhengping
Published: October 2006

Meningiomas are classified into three groups (benign, atypical, and anaplastic) based on morphologic characteristics. Atypical meningiomas, which are WHO grade 2 tumors, and anaplastic meningiomas, which are WHO grade 3 tumors, exhibit an increased risk of recurrence and premature death compared with benign WHO grade 1 tumors. Although atypical and anaplastic meningiomas account for <10% of all of meningiomas, it can be difficult to distinguish them from benign meningiomas by morphologic criteria alone. We used selective tissue microdissection to examine 24 human meningiomas and did two-dimensional gel electrophoresis to determine protein expression patterns. Proteins expressed differentially by meningiomas of each WHO grade were identified and sequenced. Proteomic analysis revealed protein expression patterns unique to WHO grade 1, 2, and 3 meningiomas and identified 24 proteins that distinguish each subtype. Fifteen proteins showed significant changes in expression level between benign and atypical meningiomas, whereas nine distinguished atypical from anaplastic meningiomas. Differential protein expression was confirmed by Western blotting and immunohistochemistry. We established differential proteomic profiles that characterize and distinguish meningiomas of increasing grades. The proteins and proteomic profiles enhance understanding of the pathogenesis of meningiomas and have implications for diagnosis, prognosis, and treatment. (Cancer Res 2006; 66(20): 10199-204)
Induction of Therapeutically Relevant Cytotoxic T Lymphocytes in Humans by Percutaneous Peptide Immunization
Authors: Yagi Hiroaki , Hashizume Hideo , Horibe Takahiro , Yoshinari Yasushi , Hata Maki , Ohshima Akihiro , Ito Taisuke , Takigawa Masahiro , Shibaki Akihiko , Shimizu Hiroshi , Seo Naohiro
Published: October 2006

Percutaneous peptide immunization (PPI) is a simple and noninvasive immunization approach to induce potent CTL responses by peptide delivery via skin with the stratum corneum removed. After such a barrier disruption in human skin, epidermal Langerhans cells, although functionally matured through the up-regulation of HLA expression and costimulatory molecules, were found to emigrate with a reduced number of dendrites. CD8+ populations binding to MHC-peptide tetramers/pentamers and producing IFN-γ appeared in the blood after PPI with HLA class I–restricted antigenic peptides. PPI with melanoma-associated peptides reduced the lesion size and suppressed further development of tumors in four of seven patients with advanced melanoma. These beneficial effects were accompanied by the generation of circulating CTLs with in vitro cytolytic activity and extensive infiltration of tetramer/pentamer-binding cells into regressing lesions. PPI elicited neither local nor systemic toxicity or autoimmunity, except for vitiligo, in patients with melanoma. Therefore, PPI represents a novel therapeutic intervention for cancer in the clinical setting. (Cancer Res 2006; 66(20): 10136-44)
Activation of EDTA-Resistant Gelatinases in Malignant Human Tumors
Authors: Chen Donghai , Kennedy Alanna , Wang Jaw-Yuan , Zeng Wei , Zhao Qiang , Pearl Michael , Zhang Mengzhen , Suo Zhenhe , Nesland Jahn M. , Qiao Yuhuan , Ng Ah-Kau , Hirashima Naoko , Yamane Tetsu , Mori Yoshiyuki , Mitsumata Masako , Ghersi Giulio , Chen Wen-Tien
Published: October 2006

Among the many proteases associated with human cancer, seprase or fibroblast activation protein α, a type II transmembrane glycoprotein, has two types of EDTA-resistant protease activities: dipeptidyl peptidase and a 170-kDa gelatinase activity. To test if activation of gelatinases associated with seprase could be involved in malignant tumors, we used a mammalian expression system to generate a soluble recombinant seprase (r-seprase). In the presence of putative EDTA-sensitive activators, r-seprase was converted into 70- to 50-kDa shortened forms of seprase (s-seprase), which exhibited a 7-fold increase in gelatinase activity, whereas levels of dipeptidyl peptidase activity remained unchanged. In malignant human tumors, seprase is expressed predominantly in tumor cells as shown by in situ hybridization and immunohistochemistry. Proteins purified from experimental xenografts and malignant tumors using antibody- or lectin-affinity columns in the presence of 5 mmol/L EDTA were assayed for seprase activation in vivo. Seprase expression and activation occur most prevalently in ovarian carcinoma but were also detected in four other malignant tumor types, including adenocarcinoma of the colon and stomach, invasive ductal carcinoma of the breast, and malignant melanoma. Together, these data show that, in malignant tumors, seprase is proteolytically activated to confer its substrate specificity in collagen proteolysis and tumor invasion. (Cancer Res 2006; 66(20): 9977-85)
Heterodimerization of Insulin-like Growth Factor Receptor/Epidermal Growth Factor Receptor and Induction of Survivin Expression Counteract the Antitumor Action of Erlotinib
Authors: Morgillo Floriana , Woo Jong Kyu , Kim Edward S. , Hong Waun Ki , Lee Ho-Young
Published: October 2006

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have been used to treat non–small cell lung cancer (NSCLC). However, the overall response rate to EGFR TKIs is limited, and the mechanisms mediating resistance to the drugs are poorly understood. Here, we report that insulin-like growth factor-I receptor (IGF-IR) activation interferes with the antitumor activity of erlotinib, an EGFR TKI. Treatment with erlotinib increased the levels of EGFR/IGF-IR heterodimer localized on cell membrane, activated IGF-IR and its downstream signaling mediators, and stimulated mammalian target of rapamycin (mTOR)–mediated de novo protein synthesis of EGFR and survivin in NSCLC cells. Inhibition of IGF-IR activation, suppression of mTOR-mediated protein synthesis, or knockdown of survivin expression abolished resistance to erlotinib and induced apoptosis in NSCLC cells in vitro and in vivo. Our data suggest that enhanced synthesis of survivin protein mediated by the IGFR/EGFR heterodimer counteracts the antitumor action of erlotinib, indicating the needs of integration of IGF-IR–targeted agents to the treatment regimens with EGFR TKI for patients with lung cancer. (Cancer Res 2006; 66(20): 10100-11)
A t(1;19)(q10;p10) Mediates the Combined Deletions of 1p and 19q and Predicts a Better Prognosis of Patients with Oligodendroglioma
Authors: Jenkins Robert B. , Blair Hilary , Ballman Karla V. , Giannini Caterina , Arusell Robert M. , Law Mark , Flynn Heather , Passe Sandra , Felten Sara , Brown Paul D. , Shaw Edward G. , Buckner Jan C.
Published: October 2006

Combined deletion of chromosomes 1p and 19q is associated with improved prognosis and responsiveness to therapy in patients with anaplastic oligodendroglioma. The deletions usually involve whole chromosome arms, suggesting a t(1;19)(q10;p10). Using stem cell medium, we cultured a few tumors. Paraffin-embedded tissue was obtained from 21 Mayo Clinic patients and 98 patients enrolled in 2 North Central Cancer Treatment Group (NCCTG) low-grade glioma trials. Interphase fusion of CEP1 and 19p12 probes detected the t(1;19). 1p/19q deletions were evaluated by fluorescence in situ hybridization. Upon culture, one oligodendroglioma contained an unbalanced 45,XX,t(1;19)(q10;p10). CEP1/19p12 fusion was observed in all metaphases and 74% of interphase nuclei. Among Mayo Clinic oligodendrogliomas, the prevalence of fusion was 81%. Among NCCTG patients, CEP1/19p12 fusion prevalence was 55%, 47%, and 0% among the oligodendrogliomas, mixed oligoastrocytomas, and astrocytomas, respectively. Ninety-one percent of NCCTG gliomas with 1p/19q deletion and 12% without 1p/19q deletion had CEP1/19p12 fusion (P < 0.001, χ2 test). The median overall survival (OS) for all patients was 8.1 years without fusion and 11.9 years with fusion (P = 0.003). The median OS for patients with low-grade oligodendroglioma was 9.1 years without fusion and 13.0 years with fusion (P = 0.01). Similar significant median OS differences were observed for patients with combined 1p/19q deletions. The absence of alterations was associated with a significantly shorter OS for patients who received higher doses of radiotherapy. Our results strongly suggest that a t(1;19)(q10;p10) mediates the combined 1p/19q deletion in human gliomas. Like combined 1p/19q deletion, the 1;19 translocation is associated with superior OS and progression-free survival in low-grade glioma patients. (Cancer Res 2006; 66(20): 9852-61)
Targeting Liposomal Chemotherapy via Both Tumor Cell–Specific and Tumor Vasculature–Specific Ligands Potentiates Therapeutic Efficacy
Authors: Pastorino Fabio , Brignole Chiara , Di Paolo Daniela , Nico Bice , Pezzolo Annalisa , Marimpietri Danilo , Pagnan Gabriella , Piccardi Federica , Cilli Michele , Longhi Renato , Ribatti Domenico , Corti Angelo , Allen Theresa M. , Ponzoni Mirco
Published: October 2006

Neuroblastoma, the most common solid tumor of infancy derived from the sympathetic nervous system, continues to present a formidable clinical challenge. Sterically stabilized immunoliposomes (SIL) have been shown to enhance the selective localization of entrapped drugs to solid tumors, with improvements in therapeutic indices. We showed that SIL loaded with doxorubicin (DXR) and targeted to the disialoganglioside receptor GD2 [aGD2-SIL(DXR)] led to a selective inhibition of the metastatic growth of experimental models of human neuroblastoma. By coupling NGR peptides that target the angiogenic endothelial cell marker aminopeptidase N to the surface of DXR-loaded liposomes [NGR-SL(DXR)], we obtained tumor regression, pronounced destruction of the tumor vasculature, and prolonged survival of orthotopic neuroblastoma xenografts. Here, we showed good liposome stability, long circulation times, and enhanced time-dependent tumor accumulation of both the carrier and the drug. Antivascular effects against animal models of lung and ovarian cancer were shown for formulations of NGR-SL(DXR). In the chick embryo chorioallantoic assay, NGR-SL(DXR) substantially reduced the angiogenic potential of various neuroblastoma xenografts, with synergistic inhibition observed for the combination of NGR-SL(DXR) with aGD2-SIL(DXR). A significant improvement in antitumor effects was seen in neuroblastoma-bearing animal models when treated with the combined formulations compared with control mice or mice treated with either tumor- or vascular-targeted liposomal formulations, administered separately. The combined treatment resulted in a dramatic inhibition of tumor endothelial cell density. Long-term survivors were obtained only in animals treated with the combined tumor- and vascular-targeted formulations, confirming the pivotal role of combination therapies in treating aggressive metastatic neuroblastoma. (Cancer Res 2006; 66(20): 10073-82)
Effective Treatment of Tumors with Strong β-Catenin/T-Cell Factor Activity by Transcriptionally Targeted Oncolytic Herpes Simplex Virus Vector
Authors: Kuroda Toshihiko , Rabkin Samuel D. , Martuza Robert L.
Published: October 2006

The Wnt/β-catenin/T-cell factor (Tcf) pathway is aberrantly up-regulated in the majority of colorectal cancers (CRC) and hepatoblastomas due to either an APC or β-catenin gene mutation. We constructed synthetic promoters, T and TE, which contain tandem repeats of a Tcf responsive element without and with the human 4F2 gene intronic enhancer, respectively. Although the T and TE promoters showed higher transcriptional activity than a control promoter in all CRC and hepatoblastoma cell lines tested, with low activities in most other tumor cell lines, the level of transcription varied considerably among the CRC and hepatoblastoma cell lines. In some CRC cell lines, the TE promoter displayed higher levels of transcription than even the human CMVIE promoter. In those CRC cells, the APC gene mutations were located within a small segment between the first and second 20-amino-acid repeats in the mutation cluster region of the APC protein. We created a transcriptionally targeted oncolytic herpes simplex virus vector (bM24-TE) in which replication is driven by the TE promoter. This vector efficiently and specifically replicated in and killed tumor cells with strong β-catenin/Tcf signaling. Intratumoral injection of bM24-TE significantly reduced the growth of highly β-catenin active SW480 CRC tumors and induced a complete response in half of them, whereas it had no effect on the growth of β-catenin-inactive A549 tumors. Our results suggest that a transcriptionally regulated oncolytic herpes vector targeting β-catenin/Tcf signal is very efficacious against CRC tumors carrying an APC gene mutation between the first and second 20-amino-acid repeats. (Cancer Res 2006; 66(20): 10127-35)
Essential Role of T-Cell Factor/β-Catenin in Regulation of Rad6B: A Potential Mechanism for Rad6B Overexpression in Breast Cancer Cells
Authors: Shekhar Malathy P.V. , Tait Larry , Gerard Brigitte
Published: October 2006

We have previously shown that the postreplication DNA repair gene Rad6B plays a critical role in the maintenance of genomic integrity of human breast cells. Whereas normal breast cells express low levels of Rad6B, increases in Rad6B expression occur in hyperplasia with overexpression in breast carcinomas. Here, we show that the human Rad6B gene is a transcriptional target of T-cell factor (TCF)-4/β-catenin/p300. Rad6B promoter activity is subject to negative regulation in normal human MCF10A breast cells whereas it is constitutively active in metastatic MDA-MB-231 breast cancer cells. Derepression and activation of Rad6B promoter in MCF10A cells require coexpression of β-catenin and p300. Using electrophoresis mobility shift assay, Western blot analysis of electrophoresis mobility shift assay, UV cross-linking, and chromatin immunoprecipitation assay, we show that Rad6B transcriptional repression in MCF10A cells is due to paucity of transcriptionally active β-catenin assembled on the TCF binding sequence in the Rad6B promoter rather than to a deficit/decreased affinity of TCF-4 for the TCF binding element in Rad6B promoter. Three-dimensional epithelial acini generated in vitro from MCF10A cells cotransfected with β-catenin and p300 showed β-catenin expression on the membrane, cytoplasm, and/or nuclei with concomitant Rad6 overexpression, whereas control acini showed β-catenin on the membranes and negligible Rad6 expression. Immunohistochemical analysis of 12 breast carcinomas showed an ∼80% correlation between Rad6 and β-catenin expression, and combined nuclear and cytoplasmic staining of β-catenin and Rad6 was detected in 25% of the breast carcinomas. In vivo implantation of MCF10A-Rad6B cells produced hyperplastic lesions. These data reveal a potentially important role for transcriptionally active β-catenin in the regulation of Rad6B gene expression, and link aberrant β-catenin signaling with transcriptional deregulation of Rad6B and breast cancer development. (Mol Cancer Res 2006;4(10):729–45)
Genetic and Expression Aberrations of E3 Ubiquitin Ligases in Human Breast Cancer
Authors: Chen Ceshi , Seth Arun K. , Aplin Andrew E.
Published: October 2006

Recent studies revealed that E3 ubiquitin ligases play important roles in breast carcinogenesis. Clinical research studies have found that (epi)-genetic (deletion, amplification, mutation, and promoter methylation) and expression aberration of E3s are frequent in human breast cancer. Furthermore, many studies have suggested that many E3s are either oncogenes or tumor suppressor genes in breast cancer. In this review, we provide a comprehensive summary of E3s, which have genetic and/or expression aberration in breast cancer. Most cancer-related E3s regulate the cell cycle, p53, transcription, DNA repair, cell signaling, or apoptosis. An understanding of the oncogenic potential of the E3s may facilitate identifying and developing individual E3s as diagnosis markers and drug targets in breast cancer. (Mol Cancer Res 2006;4(10):695–707)
Spectroscopic Approaches to the Conformation of Tau Protein in Solution and in Paired Helical Filaments
Authors: von Bergen M. , Barghorn S. , Jeganathan S. , Mandelkow E.-M. , Mandelkow E.
Published: October 2006

The abnormal aggregation of the microtubule-associated protein tau into paired helical filaments is one the hallmarks of Alzheimer’s disease. This aggregation is based in the partial formation of β-structure. In contrast, the soluble protein shows a mostly random coil structure, as judged by circular dichroism, Fourier transform infrared, X-ray scattering and biochemical assays. Here, we review the basis of the natively unstructured character of tau, as well as recent studies of residual structure and long-range interactions between different domains of the protein. Analysis of the primary structure reveals a very low content of hydrophobic amino acids and a high content of charged residues, both of which tend to counteract a well-folded globular state of proteins. In the case of tau, the low overall hydrophobicity is sufficient to explain the lack of folding. This is in contrast to other proteins which also carry an excess charge at physiological pH. By tryptophan scanning mutagenesis and fluorimetry we found that most of the sequence is solvent exposed. Analysis of the hydrodynamic radii confirms a mostly random coil structure of various tau isoforms and tau domains. The proteins can be further expanded by denaturation with GdHCl which indicates some global folding. This was substantiated by a FRET-based approach where the distances between different domains of tau were determined. The combined data show that tau is mostly disordered and flexible but tends to assume a hairpin-like overall fold which may be important in the transition to a pathological aggregate.
Ectodomain Shedding of the Amyloid Precursor Protein: Cellular Control Mechanisms and Novel Modifiers
Authors: Lichtenthaler Stefan F.
Published: October 2006

Proteolytic cleavage in the ectodomain of the amyloid precursor protein (APP) is a key regulatory step in the generation of the Alzheimer’s disease amyloid-β (Aβ) peptide and occurs through two different protease activities termed α- and β-secretase. Both proteases compete for APP cleavage, but have opposite effects on Aβ generation. At present, little is known about the cellular pathways that control APP α- or β-secretase cleavage and thus Aβ generation. To explore the contributory pathways in more detail we have recently employed an expression cloning screen and identified several activators of APP cleavage by α- or β-secretase. Among them were known activators of APP cleavage, for example protein kinase A, and novel activators, such as endophilin and the APP homolog amyloid precursor-like protein 1 (APLP1). Mechanistic analysis revealed that both endophilin and APLP1 reduce the rate of APP endocytosis and strongly increase APP cleavage by α-secretase. This review summarizes the results of the expression cloning screen in the context of recent developments in our understanding of the cellular regulation of APP α-secretase cleavage. Moreover, it highlights the particular importance of endocytic APP trafficking as a prime modulator of APP shedding.
Role of Amyloid Precursor Protein, Amyloid-β and γ-Secretase in Cholesterol Maintenance
Authors: Hartmann Tobias
Published: October 2006

Lipids play an important part as risk factors for Alzheimer’s disease. This article summarizes the current understanding of the molecular mechanism by which amyloid-β (Aβ) peptides regulate cholesterol and sphingomyelin metabolism, and how in return cholesterol and sphingomyelin regulate Aβ peptide production. An understanding of the physiological function of amyloid precursor protein processing and Aβ function is critical for the development of future therapeutic approaches, e.g. statin treatment.
Growth Hormone-Secreting Tumors: Genetic Aspects and Data from Animal Models
Authors: Lytras Aristides , Tolis George
Published: October 2006

Hereditary cases of growth hormone (GH)-secreting tumors have been classified into three clinical entities: the multiple endocrine neoplasia type 1 (MEN1) syndrome, the Carney complex (CNC) and the isolated familial somatotropinomas (IFS). The genomic defects associated with MEN1 are all linked to various mutations of the MEN1 gene, which is located at chromosome 11q13 and codes for menin, a nuclear protein expressed in multiple tissues. Inactivation of the MEN1 gene appears to be only rarely associated with sporadic pituitary tumor development. A CNC-associated gene, the type 1 α regulatory subunit (R1α) of cAMP-dependent protein kinase A (PRKAR1A), is located at 17q23–24. A second CNC candidate gene is located at chromosome 2p15–16, with characteristics of inheritance consistent with an oncogene; however, this gene has not been identified yet. PRKAR1A mutations are infrequently associated with sporadic GH-secreting adenomas. A candidate IFS gene is located at 11q13, in proximity to the MEN1 gene, at a locus narrowed down to a 2.21-Mb area, with approximately 50 genes, that does not appear to include the MEN1 gene. Apart from the linkage of IFS to 11q13, a possible linkage to 2p16 has also been raised, although data are still inconclusive. This manuscript reviews genetic aspects of hereditary GH-secreting tumors, data from animal models resulting from the inactivation of the MEN1 and PRKAR1A tumor suppressor genes and available in vitro data regarding possible functions of menin, the product of the MEN1 gene.
Dynamic Tests and Basal Values for Defining Active Acromegaly
Authors: Tzanela M.
Published: October 2006

Acromegaly is a rare disease caused by excess secretion of growth hormone (GH), usually from a pituitary somatotrope adenoma. The prevalence of acromegaly is 38–40 cases/1,000,000 subjects, while the annual incidence is 3 new cases/1,000,000 subjects. The increase in morbidity and mortality associated with acromegaly is the result of GH and insulin-like growth factor (IGF)-I oversecretion and the direct mass effect of the pituitary tumor. Once the disease is clinically suspected, laboratory evaluation is mandatory to establish diagnosis. The standard method for the diagnosis of acromegaly has been the measuring of GH nadir (GHn) during an oral glucose tolerance test (OGTT) which in normal individuals is undetectable, while acromegalics failed to suppress GH levels. Determination of IGF-I levels is useful as they correlate with clinical features of acromegaly and with the 24-hour mean GH levels. According to the more recent consensus, a random GH <0.4 µg/l and IGF-I in the age- and gender-matched normal range exclude the diagnosis of acromegaly. If either of these levels are not achieved, an OGTT should be performed, and then GHn <1 µg/l during OGTT excludes acromegaly. The therapeutic goals for acromegaly include the relief of sings and symptoms, the control of the tumor mass, the correction of the biochemical markers to normal levels, and the reduction in morbidity and mortality to the expected rate for the normal population. According to the 2000 consensus criteria, biochemical control of acromegaly is achieved when circulating IGF-I is reduced to an age- and sex-adjusted normal range and GHn during OGTT is <1 µg/l. There is debate in the literature whether GHn or IGF-I levels are more reliable to evaluate treatment of acromegaly. It has been reported that 15% of acromegalics with GHn <1 µg/l after treatment demonstrate abnormal IGF-I levels, while 15% of patients with normal IGF-I fail to suppress GH levels <1 µg/l during the OGTT. Probably, GHn and IGF-I levels represent two different aspects of disease activity in acromegaly. While IGF-I evaluates the secretory function of the somatotropes, GHn provides evidence of the presence or absence of functional autonomy of these cells.
Acromegaly and the Cardiovascular System
Authors: Lombardi Gaetano , Galdiero Mariano , Auriemma Renata S. , Pivonello Rosario , Colao Annamaria
Published: October 2006

Acromegaly is characterized by an increased cardiovascular morbidity and mortality. In fact, growth hormone and insulin-like growth factor-I excess induces a specific cardiomyopathy. The heart is involved from the very early stages of the disease in which the hyperkinetic syndrome (high heart rate and increased systolic output) takes place. Frequently, if the disease is untreated for many years or unsuccessfully treated, concentric biventricular hypertrophy and diastolic dysfunction can develop and, at least, lead to diastolic congestive heart failure. Rhythm disturbances and valve dysfunction are also frequently described in acromegaly. The coexistence of other complications, such as diabetes and arterial hypertension, can induce the worsening of acromegalic cardiomyopathy. Control of acromegaly by surgery or pharmacotherapy could improve cardiovascular morbidity thanks to decreasing left ventricular mass and reducing cardiac dysfunction. In conclusion, an early diagnosis and a careful evaluation of cardiac function, morphology and activity seem to be mandatory in acromegaly.
Cancers Associated with Acromegaly
Authors: Jenkins Paul J.
Published: October 2006

Acromegaly is characterised by excessive levels of circulating growth hormone and its tissue mediator, insulin-like growth factor (IGF)-I. Prior to effective treatment and lowering of growth hormone and IGF-I, the majority of patients with the disease died by the age of 60 years, largely due to diabetes mellitus, cardiovascular and cerebrovascular diseases. More recently, it has become apparent that patients with acromegaly may also have an increased prevalence of colorectal adenomas and cancer. This may be due to elevated IGF-I, which is implicated in the development of sporadic colorectal cancer, and environmental factors, such as the bile acid deoxycholic acid, the levels of which are also increased in acromegaly. There is some evidence to suggest that breast and prostatic malignancies might also be increased in acromegaly. However, these associations have been based mostly on small epidemiological surveys and circumstantial evidence. Large-scale epidemiological studies are required to clarify this issue.
Transsphenoidal Microsurgery for Newly Diagnosed Acromegaly: A Personal View after More than 1,000 Operations
Authors: Lüdecke Dieter K. , Abe Takumi
Published: October 2006

The aim of this short review is to inform about the possibilities and limits of transnasal microsurgery in acromegaly. The current reports on surgical remissions, according to the strict criteria with international consensus using age- and sex-related normal levels for insulin-like growth factor-I and suppression of growth hormone (GH) with oral glucose tolerance below 1 µg/l, are more or less agreeable with values between 34 and 74%. In microadenomas (<10 mm in diameter), 59–95% remissions are published. Some improvement might be achieved in macroadenomas which presently have a chance of 26–68% to be satisfactorily operated on. Special instruments introduced by us to visualize and remove partially invasive adenoma parts are described. Intraoperative magnetic resonance imaging is discussed. With intraoperative measurement of GH, small adenoma rests <3 mm can be diagnosed. When GH did not sufficiently decline, an additional tumor search resulted in a significant improvement in results in resectable macroadenomas. With these techniques, we achieved remission rates which can hardly be further increased (micros 95%, macros 68%). In grossly invasive grade 4 adenomas, which are frequent in our unit, only an 80–95% reduction in tumor mass is feasible. Preoperative treatment with somatostatin analogues as used in most of our patients reduces the comorbidity and facilitates adenoma removal which is still controversially discussed in the literature. The complication rate of microsurgery in experienced hands is low.
Medical Treatment of Acromegaly: Comorbidities and Their Reversibility by Somatostatin Analogs
Authors: Tolis George , Angelopoulos Nicholas G. , Katounda Eugenia , Rombopoulos Grigorios , Kaltzidou Victoria , Kaltsas Dimitrios , Protonotariou Anthi , Lytras Aristides
Published: October 2006

Relief of symptoms can be achieved following surgery for growth hormone (GH)-secreting adenomas, as well as after pharmacological therapy with somatostatin analogs. Recently, long-acting somatostatin analog depot formulations, octreotide LAR and lanreotide SR have become available. Somatostatin analogs control GH/insulin-like growth factor (IGF)-1 excess, induce tumor shrinkage in a high proportion of patients, improve symptoms of acromegaly with relatively limited side effects and are successfully administered in patients not suitable for surgery. Furthermore, preoperative somatostatin analogs have been suggested to improve outcome for tumors with limited invasiveness, while surgical tumor debulking in cases that are, at least partially, somatostatin resistant, increases the achievement of normal IGF-1 levels by postoperative somatostatin analog treatment. Effective control of hypertension, as well as diabetes, is mandatory in order to reduce the increased vascular morbidity/mortality. Control of GH/IGF-1 excess generally improves glucose metabolism. Somatostatin analogs improve insulin sensitivity, exerting, however, a concomitant direct inhibitory effect on insulin secretion, with a net balance leaning towards a deterioration in glucose homeostasis. As a result, oral insulin secretagogues (and/or insulin) should probably be preferred to insulin sensitizers in acromegalic patients developing diabetes while on somatostatin analogs. Nevertheless, glucose tolerance remains normal in most of the nondiabetic acromegalic patients, while diabetic acromegalic patients on insulin are at risk for hypoglycemia during initiation of somatostatin analog therapy. Although successful management of acromegaly has been associated with improvement in morphological and functional parameters of cardiomyopathy, limited and conflicting information is available regarding the effect on blood pressure control. Contradictory results have also been reported regarding sleep hypopnea or apnea in treated acromegalic patients. As acromegalic skeletal abnormalities are rather irreversible, apneic episodes may persist after normalization of hormonal levels. Aggressive therapy, including surgery, pharmacological treatment and, in some cases, pituitary irradiation, aiming at normalization of IGF-1 levels, is required for arthropathy management. Some improvement in pain, crepitus and range of motion has been observed after treatment with somatostatin analogs. Information on the impact of disease control, either by surgery or somatostatin analog treatment, on gonadal function is limited. Finally, the link between the hormonal/biochemical and the psychiatric/psychological features of acromegaly, as well as a potential basis for positive effects of somatostatin analog therapy remain unclear.
Individual SNP Allele Reconstruction from Informative Markers Selected by a Non-Linear Gauss-Type Algorithm
Authors: Moskvina Valentina , Schmidt Karl Michael
Published: October 2006

Objectives: In view of the linkage disequilibrium structure of the genome, the selection of maximally informative SNP markers is a fundamental issue in the design of association studies. Currently used selection methods rely on pairwise marker correlation or informativity measures for subsets of markers. Nevertheless, the selected markers do not provide a completely satisfactory description of the individual remaining markers. The number of tag markers can be further reduced by using haplotypic information, but then the results of association analysis are difficult to interpret. Methods and Results: We propose a non-linear Gauss-type algorithm selecting a subset of markers which is optimal with respect to the informativity measures and allows an explicit reconstruction of all other known markers, thus permitting direct inference of allelic association. The selection is based on the haplotype distribution in the population, but can be adapted to work with unphased genotypes directly. Conclusions: The proposed algorithm provides a rational methodology of informative marker selection, allowing for control and optimisation of information content and full marker reconstruction. Moreover, the reconstruction step can also be applied to tag markers selected using a different method at the stage of study design, identifying those markers which cannot be uniquely recovered from the chosen tags.
Intraocular Lens Implantation in Patients with Juvenile Idiopathic Arthritis-Associated Uveitis
Authors: Kotaniemi Kaisu , Penttilä Hannu
Published: October 2006

Objective: To evaluate the development of cataract and the results of cataract surgery with intraocular lens (IOL) implantation in patients with chronic uveitis associated with juvenile idiopathic arthritis (JIA). Patients and Methods: A hospital-based retrospective case series consisted of 25 patients with JIA-associated uveitis. The mean age of the patients was 5.8 years at the onset of arthritis and 6.8 years at the onset of uveitis. During the 15-year study period cataract surgery with implantation of an IOL was performed in 36 eyes. In 17 eyes phacoemulsification and initial posterior capsulectomy with anterior core vitrectomy were performed. The treatment of JIA and uveitis was carefully adjusted with systemic immunosuppressive drugs and topical corticosteroids perioperatively. The mean postoperative follow-up period was 3.3 years. Results: The first signs of cataract were observed 2.3 years (mean) after the diagnosis of uveitis and the cataract operation of the first eye was performed 4.5 years (mean) after the diagnosis of uveitis. After IOL surgery the visual result was good (≧0.5) in 64%, moderate (0.3 to <0.5) in 11% and impaired (<0.3) in 25% of eyes. Secondary cataract developed in 16 eyes but in none of the eyes with initial posterior capsulectomy and core vitrectomy. Secondary glaucoma developed in 18 eyes, retinal detachment in 2, cystoid macular edema in 16 and band keratopathy in 12 eyes. Conclusion: Cataract is an early complication of JIA-associated uveitis. Under strict control of uveitis, IOL implantation is an important alternative in visual rehabilitation for this type of patient.
Ontogenic Expression of Estrogen Receptor-α in Female Rat Corneas
Authors: Kato Hideo , Naito Kazuyoshi , Katsu Yoshinao , Watanabe Hajime , Ohta Yasuhiko , Iguchi Taisen
Published: October 2006

Purpose: To investigate ontogenic expression of estrogen receptor (ER)-α in female rat corneas, as part of basic studies to elucidate the mechanism of estrogenic effects on the corneas. Methods: The expression and localization of ERα were determined using quantitative reverse transcribed-polymerase chain reaction methodology and immunohistochemistry in the corneas of female rats on day 14 of gestation and postnatal days (PNDs) 0, 21, and 60. Results: Quantitative analysis of ERα mRNA revealed that ERα gene expression increased approximately 4 times on PND 21 and about 10 times on PND 60, as compared with expression levels detected on PND 0. Immunohistochemical analysis revealed that expression of ERα protein was evident only in nuclei of the corneal epithelial cells from PND 21 onward. Conclusion: Ontogenic expression of ERα occurred in female rat corneas.
Tube Pharyngostomy: A Simple Method for Prolonged Intubation of the Foregut following Oesophagogastric Surgery
Authors: Katsoulis I.E. , Livingstone J.I. , Sagor G.R.
Published: October 2006

Tube pharyngostomy involves the percutaneous passage of a tube through the pharynx as an alternative to nasogastric intubation. We use this method for upper gastrointestinal decompression after oesophagectomies and total gastrectomies where prolonged intubation of the foregut is anticipated. It is simple to perform and very well tolerated as compared to a nasogastric tube. The pharyngostomy tube can also be used for enteral feeding. We present here the technique in detail and our experience with 67 procedures over the last 6 years where only few minor complications were encountered. We also review the literature for previous reports of pharyngostomy.
Subjective Memory Complaints and Cognitive Impairment in Older People
Authors: Reid Louise M. , MacLullich Alasdair M.J.
Published: October 2006

Subjective memory complaints (SMCs) are common in older people and are often thought to indicate cognitive impairment. We reviewed research on the relationship between SMCs and (a) current cognitive function, (b) risk of future cognitive decline, and (c) depression and personality. SMCs were found to be inconsistently related to current cognitive impairment but were more strongly related to risk of future cognitive decline. However, SMCs were consistently related to depression and some personality traits, e.g. neuroticism. In conclusion, the determinants of SMCs are complex. The utility of SMCs in the diagnosis of pre-dementia states (e.g. mild cognitive impairment) is uncertain and requires further evaluation.