bluuebunny/crossref_metadata_2025 huggingface dataset:
Progressive Magnetic Resonance Image Reconstruction Based on Iterative Solution of a Sparse Linear System
Authors: Kadah Yasser M. , Fahmy Ahmed S. , Gabr Refaat E. , Heberlein Keith , Hu Xiaoping P.
Published: April 2006

Image reconstruction from nonuniformly sampled spatial frequency
domain data is an important problem that arises in computed
imaging. Current reconstruction techniques suffer from limitations
in their model and implementation. In this paper, we present a new
reconstruction method that is based on solving a system of linear
equations using an efficient iterative approach. Image pixel
intensities are related to the measured frequency domain data
through a set of linear equations. Although the system matrix is
too dense and large to solve by direct inversion in practice, a
simple orthogonal transformation to the rows of this matrix is
applied to convert the matrix into a sparse one up to a certain
chosen level of energy preservation. The transformed system is
subsequently solved using the conjugate gradient method. This
method is applied to reconstruct images of a numerical phantom as
well as magnetic resonance images from experimental spiral imaging
data. The results support the theory and demonstrate that the
computational load of this method is similar to that of standard
gridding, illustrating its practical utility.
Brain Structure Segmentation from MRI by Geometric Surface Flow
Authors: Heckenberg Greg , Xi Yongjian , Duan Ye , Hua Jing
Published: April 2006

We present a method for semiautomatic segmentation of brain
structures such as thalamus from MRI images based on the concept
of geometric surface flow. Given an MRI image, the user can
interactively initialize a seed model within region of interest.
The model will then start to evolve by incorporating both boundary
and region information following the principle of variational
analysis. The deformation will stop when an equilibrium state is
achieved. To overcome the low contrast of the original image data,
a nonparametric kernel‐based method is applied to simultaneously
update the interior probability distribution during the model
evolution. Our experiments on both 2D and 3D image data
demonstrate that the new method is robust to image noise and
inhomogeneity and will not leak from spurious edge gaps.
Effect of complexation with lanthanide metal ions on the photochromism of (1,3,3‐trimethyl‐5′‐hydroxy‐6′‐formyl‐ indoline‐spiro2,2′‐[2h]chromene) in different media
Authors: Attia M. S. , Khalil M. H. , Abdel-Mottaleb M. S. A. , Lukyanova M. B. , Alekseenko Yu. A. , Lukyanov Boris
Published: April 2006

Complexation of lanthanide ions {Ln(III) ions [Tb(III), Eu(III),
or Sm(III)]} with the spiropyran‐derived merocyanine obtained
in dark and under steady irradiation of indoline spiropyran
(1,3,3‐trimethyl‐5′‐hydroxy‐6′‐formyl‐indoline‐spiro‐2,2′‐[2H]chromene) induces a noticeable hypsochromic shift of
about 10–110 nm of its visible absorption band concomitant
with hypochromic effect and influences its thermal bleaching in
the dark. The effect of lanthanide ions and medium on
photochromic, spectral‐and‐kinetic, and luminescence properties of
the spiropyran and its complexes in solution and polymer matrix of
polymethylmethacrylate (PMMA) is studied. Efficient energy
transfer from the spiropyran moiety results in efficient typical
luminescence from the Ln(III) ion that becomes more pronounced in
polar nonalcoholic solvents and PMMA solid matrix. Moreover,
luminescence mappings for pattern recognition analysis have been
obtained from which the nature of the solvent and/or the ligand is
clearly identified.
Experimental Study of a Radial Turbine Using Pitch‐ControlledGuide Vanes for Wave Power Conversion
Authors: Takao Manabu , Fujioka Yoshihiro , Homma Hiroki , Kim Tae-Whan , Setoguchi Toshiaki
Published: April 2006

In order to develop a high‐performance radial turbine for wave
power conversion, a radial turbine with pitch‐controlled guide
vanes has been proposed and manufactured in the study. The
proposed radial turbine has been investigated experimentally by
model testing under steady and sinusoidal flow conditions. Then,
the experimental results have been compared with those of the
conventional radial turbine for wave power conversion, that is, a
radial turbine with fixed guide vanes. As a result, the running
characteristics of the proposed radial turbine under steady and
sinusoidal flow conditions were clarified and the effect of
diffuser setting angle of guide vane on the turbine
characteristics was presented. Furthermore, it seems
that the proposed radial turbine is much superior to the
conventional radial turbine.
Existence of solutions to Sobolev‐type partial neutraldifferential equations
Authors: Agarwal Shruti , Bahuguna Dhirendra
Published: April 2006

This work is concerned with a nonlocal partial neutral
differential equation of Sobolev type. Specifically, existence of
the solutions to the abstract formulations of such type of
problems in a Banach space is established. The results are
obtained by using Schauder′s fixed point theorem. Finally, an
example is provided to illustrate the applications of the
abstract results.
Reduced Atherosclerotic Lesion Size in P‐Selectin Deficient Apolipoprotein E‐Knockout Mice Fed a Chow but Not a Fat Diet
Authors: Bourdillon Marie-Claude , Randon Jacques , Barek Lydie , Zibara Kazem , Covacho Chantal , Poston Robin N , Chignier Elza , McGregor John L.
Published: April 2006

Endothelial cells lining atherosclerotic, but not healthy sites, on human arteries express P‐selectin. We investigated the role of P‐selectin on the development of vascular lesions in an ApoE−/− male mice. Double‐knockout (ApoE−/−, P‐selectin-/-; DKO) were compared to single‐knockout (ApoE−/−; SKO) mice. They were fed a chow or fat diet for 3, 6, 15, and 20 weeks, without any differences in cholesterol levels. DKO mice fed a chow diet exhibited a ratio of lesion area over media lower than SKO mice, for 3 (P < .03) , 6 (P < .001), and 15 (P < .02) weeks. DKO mice fed a fat diet showed a lower ratio only at 3 weeks. P‐selectin deficiency in ApoE−/− mice has a protective effect in atherosclerotic lesions development. Reduction of lesion size depends on diet type and duration. A fat diet could neutralize the beneficial effects of P‐selectin deficiency, inducing atherosclerotic lesions via probably other adhesion molecules.
Cloning and Expression of Human Membrane‐Bound and Soluble Engineered T Cell Receptors for Immunotherapy
Authors: Alajez Nehad M. , Eghtesad Saman , Finn Olivera J.
Published: April 2006

We report here the design and construction of several gene vectors
for expression in mammalian cells of membrane‐bound and soluble
human T cell receptors (TR). We designed a vector
(TR‐ALPHA‐IRES‐TR‐BETA pEF4) that encodes high‐level expression of
the full‐length TR on the surface of T cells. Furthermore, we
engineered TR that does not require the presence of endogenous CD3
molecules for surface expression and thus expression is not
limited to T cells. We also constructed a vector encoding a
single‐chain TR (scTR) as a fusion protein of
V‐ALPHA‐V‐BETA‐C‐BETA with CD3Z. Since it is encoded and expressed
as a single molecule, this scTR is well suited for gene therapy.
Lastly, we successfully used a mammalian expression vector for
generation of soluble human TR. The approaches we used here for
manipulation of a human tumor‐specific TR can be useful for other
investigators interested in TR‐based immunotherapy.
L1 Retrotransposons in Human Cancers
Authors: Schulz Wolfgang A.
Published: April 2006

Retrotransposons like L1 are silenced in somatic cells by a
variety of mechanisms acting at different levels. Protective
mechanisms include DNA methylation and packaging into inactive
chromatin to suppress transcription and prevent recombination,
potentially supported by cytidine deaminase editing of RNA.
Furthermore, DNA strand breaks arising during attempted
retrotranspositions ought to activate cellular checkpoints, and L1
activation outside immunoprivileged sites may elicit immune
responses. A number of observations indicate that L1 sequences
nevertheless become reactivated in human cancer. Prominently,
methylation of L1 sequences is diminished in many cancer types and
full‐length L1 RNAs become detectable, although strong expression
is restricted to germ cell cancers. L1 elements have been found to
be enriched at sites of illegitimate recombination in many
cancers. In theory, lack of L1 repression in cancer might cause
transcriptional deregulation, insertional mutations, DNA breaks,
and an increased frequency of recombinations, contributing to
genome disorganization, expression changes, and chromosomal
instability. There is however little evidence that such effects
occur at a gross scale in human cancers. Rather, as a rule, L1
repression is only partly alleviated. Unfortunately, many
techniques commonly used to investigate genetic and epigenetic
alterations in cancer cells are not well suited to detect subtle
effects elicited by partial reactivation of retroelements like L1
which are present as abundant, but heterogeneous copies.
Therefore, effects of L1 sequences exerted on the local chromatin
structure, on the transcriptional regulation of individual genes,
and on chromosome fragility need to be more closely investigated
in normal and cancer cells.
Similar Effects of General and Spinal Anaesthesia onPerioperative Stress Response in Patients Undergoing Haemorrhoidectomy
Authors: Buyukkocak Unase , Caglayan Osman , Daphan Cagatay , Aydinuraz Kuzey , Saygun Oral , Kaya Tahsin , Agalar Fatih
Published: April 2006

Surgery induces release of neuroendocrine hormones (cortisol),
cytokines (interleukin‐6: IL‐6, tumour necrosis factor‐α: TNF‐α), acute phase proteins (C‐reactive protein: CRP,
leptin). We studied the effects of general and spinal anaesthesia
on stress response to haemorrhoidectomy. Patients were assigned to
general and spinal anaesthesia groups (n = 7). Blood samples were
drawn before induction and 24 hours after surgery. Perioperative
levels of IL‐6, TNF‐α, CRP, cortisol, and leptin were
comparable among the groups. Twenty four hours after surgery,
TNF‐α and cortisol did not change; IL‐6 and CRP increased
significantly in all patients. Significant increase in leptin
levels was found in patients undergoing spinal anaesthesia. Except
for the increase in leptin levels, there was no significant
difference related to the effects of general and spinal
anaesthesia.
On semi‐inverse solutions for the time‐dependent flows of a second‐grade fluid
Authors: Mohyuddin Muhammad R. , Asghar S. , Hayat T. , Siddiqui A. M.
Published: April 2006

This paper deals with analytical solutions for the time‐dependent
equations arising in a second‐grade fluid. The solutions have been
developed by assuming certain forms of the stream function.
Expressions for velocity components are obtained for flows in
plane polar, axisymmetric cylindrical, and axisymmetric spherical
polar coordinates. The obtained solutions are compared with
existing results.
Numerical analysis of a circular arch buckling under the symmetric pressure
Authors: Go Jaegwi , Choi Youngmi , Fang Zhong Bo
Published: April 2006

The many interesting phenomena, such as snap‐through,
nonuniqueness, and stability, of a circular arch subjected to the
symmetric pressure are studied. The balance of forces of an
elemental length leads to a governing equation which is used to
investigate stable states of the arch. With specific opening angle 2a = π/3, the sensitivities of angle and curvature at
a base are surveyed for various of spring constants. The
variations of angle and curvature at an edge are almost the same if
the spring constant τ ≥ 10.
Thermal shock problem of a generalized thermoelastic layered composite material with variable thermal conductivity
Authors: Youssef H. M. , El-Bary A. A.
Published: April 2006

The dynamic treatment of one‐dimensional generalized thermoelastic
problem of heat conduction is made for a layered thin plate which
is exposed to a uniform thermal shock taking into account variable
thermal conductivity. The basic equations are transformed by
Laplace transform and solved by a direct method. The solution was
applied for a plate of sandwich structure, which is thermally
shocked, and is traction‐free in the outer sides. The inverses of
Laplace transforms are obtained numerically. The temperature, the
stress, and the displacement distributions are represented
graphically.
Semiorthogonal spline wavelets approximation forFredholm integro‐differential equations
Authors: Lakestani M. , Razzaghi M. , Dehghan M.
Published: April 2006

A method for solving the nonlinear second‐order Fredholm
integro‐differential equations is presented. The approach is based
on a compactly supported linear semiorthogonal B‐spline
wavelets. The operational matrices of derivative for B‐spline
scaling functions and wavelets are presented and utilized to
reduce the solution of Fredholm integro‐differential to the
solution of algebraic equations. Illustrative examples are
included to demonstrate the validity and applicability of the
technique.
Gastrin Enhances the Angiogenic Potential of Endothelial Cells via Modulation of Heparin-Binding Epidermal-Like Growth Factor
Authors: Clarke Philip A. , Dickson Jacqueline H. , Harris Joseph C. , Grabowska Anna , Watson Susan A.
Published: April 2006

This study examined whether gastrin modulates endothelial cell activity via heparin-binding epidermal growth factor–like growth factor (HB-EGF) expression. Human umbilical vascular endothelial cells (HUVEC) were assessed for tubule formation in the presence of amidated gastrin-17 (G17) and glycine-extended gastrin-17 (GlyG17) peptides. HB-EGF gene and protein expressions were measured by quantitative reverse transcription-PCR, immunocytochemistry, and Western blotting, and HB-EGF shedding by ELISA. Matrix metalloproteinases MMP-2, MMP-3, and MMP-9 were assessed by Western blotting. Chick chorioallantoic membrane studies measured the in vivo angiogenic potential of gastrin and microvessel density (MVD) was assessed in large intestinal premalignant lesions of hypergastrinaemic APCMin mice. MVD was also examined in human colorectal tumor and resection margin normals and correlated with serum-amidated gastrin levels (via RIA) and HB-EGF protein expression (via immunohistochemistry). HUVEC cells showed increased tubule and node formation in response to G17 (186%, P < 0.0005) and GlyG17 (194%, P < 0.0005). This was blockaded by the cholecystokinin-2 receptor (CCK-2R) antagonists JB95008 and JMV1155 and by antiserum to gastrin and HB-EGF. Gastrin peptides increased HB-EGF gene expression/protein secretion in HUVEC and microvessel-derived endothelial cells and the levels of MMP-2, MMP-3, and MMP-9. G17 promoted angiogenesis in a chorioallantoic membrane assay, and MVD was significantly elevated in premalignant large intestinal tissue from hypergastrinaemic APCMin mice. In terms of the clinical situation, MVD in the normal mucosa surrounding colorectal adenocarcinomas correlated with patient serum gastrin levels and HB-EGF expression. Gastrin peptides, acting through the CCK-2R, enhance endothelial cell activity in models of angiogenesis. This may be mediated through enhanced expression and shedding of HB-EGF, possibly resulting from increased activity of matrix metalloproteinases. This proangiogenic effect translates to the in vivo and human situations and may add to the tumorigenic properties attributable to gastrin peptides in malignancy. (Cancer Res 2006; 66(7): 3504-12)
Inactivation of von Hippel-Lindau Gene Induces Constitutive Phosphorylation of MET Protein in Clear Cell Renal Carcinoma
Authors: Nakaigawa Noboru , Yao Masahiro , Baba Masaya , Kato Shingo , Kishida Takeshi , Hattori Keiko , Nagashima Yoji , Kubota Yoshinobu
Published: April 2006

It is well known that inactivation of von Hippel-Lindau (VHL) gene predisposes for human clear cell renal carcinoma (CCRC). However, details about critical roles of VHL inactivation during tumorigenesis are still unknown. MET protein is a tyrosine kinase receptor for hepatocyte growth factor/scatter factor (HGF/SF), which regulates cell growth, cell morphology, and cell motility. We showed that MET protein overexpressed in CCRC cells was phosphorylated without HGF/SF. This constitutive phosphorylation of MET protein in CCRC cells was inhibited by the rescue of exogenous wild-type VHL gene without a decrease in expression level of MET protein. Interestingly, wild-type VHL gene suppressed the phosphorylation of MET protein only under high cell density conditions. Additionally, MET protein activated by the inactivation of VHL gene modified cell adherence, including N-cadherin and β-catenin. When activation of MET protein in CCRC cells was inhibited by the MET inhibitor K252a, the growth of CCRC cells in vitro and the tumorigenesis induced by CCRC cells in nude mice were suppressed. From these results, we concluded that inactivation of VHL gene induced constitutive phosphorylation of MET protein and modified intercellular adherence structure to trigger the cell growth released from contact inhibition, finally resulting in tumorigenesis. This is one of the mechanisms of CCRC oncogenesis, and MET protein has potential as a molecular target for novel CCRC therapies. (Cancer Res 2006; 66(7): 3699-705)
Targeted Ablation of Par-4 Reveals a Cell Type–Specific Susceptibility to Apoptosis-Inducing Agents
Authors: Affar El Bachir , Po-shan Luke Margaret , Gay Frédérique , Calvo Dominica , Sui Guangchao , Weiss Robert S. , Li En , Shi Yang
Published: April 2006

The prostate apoptosis response-4 (Par-4) protein has been shown to function as an effector of cell death in response to various apoptotic stimuli, and down-regulation of this protein has been suggested to be a key event during tumorigenesis. Several studies suggest an essential function for the COOH-terminal leucine repeats/death domain of Par-4 in mediating apoptosis. We investigated the biological role of this domain in vivo by generating knock-out mice expressing a Par-4 mutant protein lacking the COOH terminus domain. We found that the Par-4 mutant mice are viable and fertile with no overt phenotype, thus excluding an essential role for the COOH terminus domain of Par-4 in embryogenesis and developmental apoptosis. To determine the requirement of Par-4 for apoptosis, we treated primary fibroblasts with various stimuli that trigger mitochondria and membrane receptor cell death pathways. Fibroblasts isolated from Par-4 mutant mice are as sensitive as the wild-type cells to these apoptosis-inducing agents. Similar effects were observed following RNA interference (RNAi)–mediated knockdown of Par-4 in these cells. In contrast, RNAi-mediated depletion of Par-4 in HeLa cells resulted in a significant inhibition of apoptosis induced by various proapoptotic agents. Taken together, our findings provide strong genetic evidence that the proapoptotic function of Par-4 is dependent on the cellular context and raise the possibility that alterations of Par-4 function may occur during carcinogenesis. (Cancer Res 2006; 66(7): 3456-62)
Simultaneous Inhibition of PDK1/AKT and Fms-Like Tyrosine Kinase 3 Signaling by a Small-Molecule KP372-1 Induces Mitochondrial Dysfunction and Apoptosis in Acute Myelogenous Leukemia
Authors: Zeng Zhihong , Samudio Ismael J. , Zhang Weiguo , Estrov Zeev , Pelicano Hélène , Harris David , Frolova Olga , Hail Numsen , Chen Wenjing , Kornblau Steven M. , Huang Peng , Lu Yiling , Mills Gordon B. , Andreeff Michael , Konopleva Marina
Published: April 2006

Phosphoinositol-3-kinase (PI3K)/protein kinase B (AKT) and Fms-like tyrosine kinase 3 (FLT3) signaling are aberrantly activated in acute myelogenous leukemia (AML) cells. Constitutively activated AKT and FLT3 regulate leukemia cell survival and resistance to chemotherapy. In this study, we investigated the effects of the novel multiple kinase inhibitor KP372-1 on the survival of AML cell lines and primary AML samples. KP372-1 directly inhibited the kinase activity of AKT, PDK1, and FLT3 in a concentration-dependent manner. Western blot analysis indicated that KP372-1 decreased the phosphorylation of AKT on both Ser473 and Thr308; abrogated the phosphorylation of p70S6 kinase, BAD, and Foxo3a via PI3K/AKT signaling; and down-regulated expression of PIM-1 through direct inhibition of FLT3. Treatment of AML cell lines with KP372-1 resulted in rapid generation of reactive oxygen species and stimulation of oxygen consumption, followed by mitochondrial depolarization, caspase activation, and phosphatidylserine externalization. KP372-1 induced pronounced apoptosis in AML cell lines and primary samples irrespective of their FLT3 status, but not in normal CD34+ cells. Moreover, KP372-1 markedly decreased the colony-forming ability of primary AML samples (IC50 < 200 nmol/L) with minimal cytotoxic effects on normal progenitor cells. Taken together, our results show that the simultaneous inhibition of critical prosurvival kinases by KP372-1 leads to mitochondrial dysfunction and apoptosis of AML but not normal hematopoietic progenitor cells. (Cancer Res 2006; 66(7): 3737-46)
Adenoviral Gene Transfer of Stromal Cell–Derived Factor-1 to Murine Tumors Induces the Accumulation of Dendritic Cells and Suppresses Tumor Growth
Authors: Fushimi Toshiaki , O'Connor Timothy P. , Crystal Ronald G.
Published: April 2006

The human CXC chemokine, stromal cell–derived factor 1 (SDF-1α), is known to function in vitro as a chemotactic factor for lymphocytes, monocytes, and dendritic cells. In the context that dendritic cells are powerful antigen-presenting cells, we hypothesized that adenoviral gene transfer of SDF-1α to tumors might inhibit growth of preexisting tumors through attracting dendritic cells to the tumor. AdSDF-1α mediated the expression of SDF-1α mRNA and protein in A549 cells in vitro, and the supernatant of the AdSDF-1α-infected A549 cells showed chemotactic activity for dendritic cells. When syngeneic murine CT26 colon carcinoma tumors (BALB/c) and B16 melanoma and Lewis lung cell carcinoma (C57Bl/6) were injected with AdSDF-1α (5 × 108 plaque-forming units), there was an accumulation of dendritic cells and CD8+ cells within the tumor and significant inhibition of tumor growth compared with tumors injected with PBS or AdNull (control vector). The injection of AdSDF-1α into tumors induced the inflammatory enlargement and the accumulation of dendritic cells in the draining lymph node. Intratumoral AdSDF-1α administration elicited tumor-specific CTLs and adoptive transfer of splenocytes from AdSDF-1α-treated mice resulted in the elongation of survival after tumor challenge. Interestingly, in wild-type and CD4−/− mice but not in CD8−/− mice, AdSDF-1α inhibited the growth of the tumor. These observations suggest that adenoviral gene transfer of SDF-1α may be a useful strategy to accumulate dendritic cells in tumors and evoke antitumor immune responses to inhibit tumor growth. (Cancer Res 2006; 66(7): 3513-22)
PGP9.5 Methylation in Diffuse-Type Gastric Cancer
Authors: Yamashita Keishi , Park Hannah Lui , Kim Myoung Sook , Osada Motonobu , Tokumaru Yutaka , Inoue Hiroshi , Mori Masaki , Sidransky David
Published: April 2006

Diffuse-type gastric cancer (DGC) is the most deadly form of gastric cancer and is frequently accompanied by peritoneal dissemination and metastasis. The specific molecular events involved in DGC pathogenesis remain elusive. Accumulating evidence of epigenetic inactivation in tumor suppressor genes led us to conduct a comprehensive screen to identify novel methylated genes in human cancers using pharmacologic unmasking and subsequent microarray analysis. We compared differential RNA expression profiles of DGC and intestinal-type gastric cancer (IGC) cell lines treated with 5-aza-2′-deoxycytidine using microarrays containing 22,284 genes. We identified 16 methylated genes, including many novel genes, in DGC cell lines and studied PGP9.5 with particular interest. In primary gastric cancers, PGP9.5 was found to be more frequently methylated in DGCs (78%) than in IGCs (36%; DGC versus IGC, P < 0.05). Furthermore, real-time methylation-specific PCR analysis of PGP9.5 showed relatively higher methylation levels in DGC than in IGC. Our data thus implicate a molecular event common in the DGC phenotype compared with IGC. (Cancer Res 2006; 66(7): 3921-7)
3p21.3 Tumor Suppressor Gene H37/Luca15/RBM5 Inhibits Growth of Human Lung Cancer Cells through Cell Cycle Arrest and Apoptosis
Authors: Oh Juliana J. , Razfar Ali , Delgado Idolina , Reed Rebecca A. , Malkina Anna , Boctor Baher , Slamon Dennis J.
Published: April 2006

Deletion at chromosome 3p21.3 is the earliest and the most frequently observed genetic alteration in lung cancer, suggesting that the region contains tumor suppressor gene(s) (TSG). Identification of those genes may lead to the development both of biomarkers to identify high-risk individuals and novel therapeutics. Previously, we cloned the H37/Luca15/RBM5 gene from 3p21.3 and showed its TSG characteristics. To investigate the physiologic function of H37 in the lung and its mechanism of tumor suppression, we have stably transfected H37 into A549 non–small cell lung cancer cells. A549/H37 cells show significant growth inhibition compared with the vector controls by in vitro and in vivo cell proliferation assays. Using this lung cancer cell model, we have found that the molecular mechanism of H37 tumor suppression involves both cell cycle (G1) arrest and apoptosis. To further define H37's function in cell cycle/apoptotic pathways, we investigated differential expression profiles of various cell cycle and apoptosis regulatory proteins using Western blot analysis. Both cyclin A and phophorylated RB levels were decreased in H37-transfected cells, whereas expression of Bax protein was increased. Mitochondrial regulation of apoptosis further downstream of Bax was investigated, showing change in the mitochondrial membrane potential, cytochrome c release into the cytosol, and enhanced caspase-9 and caspase-3 activities. We also report that H37 may mediate apoptosis in a p53-independent manner, and Bax knockdown by small interfering RNA suggests Bax plays a functional role downstream of H37. Lastly, we proposed a tumor suppression model of H37 as a post-transcriptional regulator for cell cycle/apoptotic–related proteins. (Cancer Res 2006; (66)7: 3419-27)
Improvement of the Tumor-Suppressive Effect of Boron Neutron Capture Therapy for Amelanotic Melanoma by Intratumoral Injection of the Tyrosinase Gene
Authors: Morita Norimasa , Hiratsuka Junichi , Kondoh Hirohumi , Uno Masako , Asano Tomoyuki , Niki Yoko , Sakurai Yoshinori , Ono Koji , Harada Tamotsu , Imajo Yoshinari
Published: April 2006

Boron neutron capture therapy (BNCT) is successful when there is a sufficient 10B concentration in tumor cells. In melanoma, 10B-para-boronophenylalanine (BPA) accumulation is proportional to melanin-producing activity. This study was done to confirm enhancement of the tumor-suppressive effect of BNCT on amelanotic melanoma by intratumoral injection of the tyrosinase gene. D178 or FF amelanotic melanomas were implanted s.c. in Syrian hamsters. One group of D178- or FF-bearing hamsters (TD178 or TFF group) received intratumoral injections of pcDNA-Tyrs constructed as a tyrosinase expression plasmid. The other hamsters (pD178 and pFF groups) were injected with pUC119, and control hamsters (D178 and FF groups) only with transfection reagents. All the groups underwent immunofluorescence analysis of tyrosinase expression and BPA biodistribution studies. BNCT experiments were done at the Kyoto University Research Reactor. Tyrosinase expression increased in the tumors of the TD178 and TFF groups but remained the same in the pD178 and pFF groups. Tumor boron concentrations in the TD178 and TFF groups increased significantly (TD178: 49.7 ± 12.6 versus D178: 27.2 ± 4.9 μg/g, P < 0.0001; TFF: 30.7 ± 6.6 versus FF: 13.0 ± 4.7 μg/g, P < 0.0001). The BNCT tumor-suppressive effect was marked in the TD178 and TFF groups. In vivo transfection with the tyrosinase gene increased BPA accumulation in the tumors, the BNCT tumor-suppressive effect on amelanotic melanoma being significantly enhanced. These findings suggest a potential new clinical strategy for the treatment of amelanotic melanoma with BNCT. (Cancer Res 2006; 66(7): 3747-53)
Gonadotropins Activate Proteolysis and Increase Invasion through Protein Kinase A and Phosphatidylinositol 3-Kinase Pathways in Human Epithelial Ovarian Cancer Cells
Authors: Choi Jung-Hye , Choi Kyung-Chul , Auersperg Nelly , Leung Peter C.K.
Published: April 2006

Despite evidence that gonadotropins may facilitate peritoneal metastasis of ovarian cancer by increasing cell adhesion, the action and molecular mechanism of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in ovarian cancer invasion is not well characterized. In the present study, we investigated the effects of FSH and LH on the invasive activity and the expression of metastasis-related proteinases in human epithelial ovarian cancer by Western blot, zymography, reverse transcription-PCR (RT-PCR), ELISA, and Boyden chamber assay. Treatment with FSH or LH (10, 100, or 1,000 ng/mL) significantly increased the invasion of ovarian cancer cell lines, including BG-1, CaOV-3, and SKOV-3 cells but not OVCAR-3 cells. In addition, treatment of SKOV-3 cells with FSH or LH (100 or 1,000 ng/mL) enhanced the expression and activation of matrix metalloproteinases (MMP-2 and MMP-9) as shown by RT-PCR, gelatin zymography, and ELISA. Pretreatment with [(2R)-2-(hydroxamido-carbonylmethyl)-4-methylpentanoyl]-l-tryptophan methylamide (10 μmol/L), a total MMP inhibitor, and 3-(4-phenoxyphenylsulfonyl)-propylthiirane (20 μmol/L), a specific gelatinase inhibitor, neutralized the proinvasive effect of gonadotropins in SKOV-3 cells. In addition, the secretion of tissue inhibitor of metalloproteinases (TIMP-1 and TIMP-2) and plasminogen activator inhibitor-1 was significantly decreased by FSH and LH (100 or 1,000 ng/mL). We further showed that gonadotropins induced an increase in SKOV-3 invasiveness via the activation of protein kinase A (PKA) and phosphatidylinositol 3-kinase (PI3K) signaling pathways. Taken together, these results suggest that gonadotropins may contribute to ovarian cancer metastasis via activation of proteolysis and increase in invasion through the PKA and PI3K pathways. (Cancer Res 2006; 66(7): 3912-20)
hTERT-Immortalized Prostate Epithelial and Stromal-Derived Cells: an Authentic In vitro Model for Differentiation and Carcinogenesis
Authors: Kogan Ira , Goldfinger Naomi , Milyavsky Michael , Cohen Merav , Shats Igor , Dobler Gabriele , Klocker Helmut , Wasylyk Bohdan , Voller Maureen , Aalders Tilly , Schalken Jack A. , Oren Moshe , Rotter Varda
Published: April 2006

Prostate cancer is the most commonly diagnosed type of cancer in men, and there is no available cure for patients with advanced disease. In vitro model systems are urgently required to permit the study of human prostate cell differentiation and malignant transformation. Unfortunately, human prostate cells are particularly difficult to convert into continuously growing cultures. We report here the successful immortalization without viral oncogenes of prostate epithelial cells and, for the first time, prostate stromal cells. These cells exhibit a significant pattern of authentic prostate-specific features. In particular, the epithelial cell culture is able to differentiate into glandular buds that closely resemble the structures formed by primary prostate epithelial cells. The stromal cells have typical characteristics of prostate smooth muscle cells. These immortalized cultures may serve as a unique experimental platform to permit several research directions, including the study of cell-cell interactions in an authentic prostate microenvironment, prostate cell differentiation, and most significantly, the complex multistep process leading to prostate cell transformation. (Cancer Res 2006; 66(7): 3531-40)
Targeting PIM Kinases Impairs Survival of Hematopoietic Cells Transformed by Kinase Inhibitor–Sensitive and Kinase Inhibitor–Resistant Forms of Fms-Like Tyrosine Kinase 3 and BCR/ABL
Authors: Adam Myriam , Pogacic Vanda , Bendit Marina , Chappuis Richard , Nawijn Martijn C. , Duyster Justus , Fox Casey J. , Thompson Craig B. , Cools Jan , Schwaller Juerg
Published: April 2006

Previous studies have shown that activation of the signal transducer and activator of transcription 5 (STAT5) plays an essential role in leukemogenesis mediated through constitutive activated protein tyrosine kinases (PTK). Because PIM-1 is a STAT5 target gene, we analyzed the role of the family of PIM serine/threonine kinases (PIM-1 to PIM-3) in PTK-mediated transformation of hematopoietic cells. Ba/F3 cells transformed to growth factor independence by various oncogenic PTKs (TEL/JAK2, TEL/TRKC, TEL/ABL, BCR/ABL, FLT3-ITD, and H4/PDGFβR) show abundant expression of PIM-1 and PIM-2. Suppression of PIM-1 activity had a negligible effect on transformation. In contrast, expression of kinase-dead PIM-2 mutant (PIM-2KD) led to a rapid decline of survival in Ba/F3 cells transformed by FLT3-ITD but not by other oncogenic PTKs tested. Coexpression of PIM-1KD and PIM-2KD abrogated growth factor–independent growth of Ba/F3 transformed by several PTKs, including BCR/ABL. Targeted down-regulation of PIM-2 by RNA interference (RNAi) selectively abrogated survival of Ba/F3 cells transformed by various Fms-like tyrosine kinase 3 (FLT3)–activating mutants [internal tandem duplication (ITD) and kinase domain] and attenuated growth of human cell lines containing FLT3 mutations. Interestingly, cells transformed by FLT3 and BCR/ABL mutations that confer resistance to small-molecule tyrosine kinase inhibitors were still sensitive to knockdown of PIM-2, or PIM-1 and PIM-2 by RNAi. Our observations indicate that combined inactivation of PIM-1 and PIM-2 interferes with oncogenic PTKs and suggest that PIMs are alternative therapeutic targets in PTK-mediated leukemia. Targeting the PIM kinase family could provide a new avenue to overcome resistance against small-molecule tyrosine kinase inhibitors. (Cancer Res 2006; 66(7): 3828-35)
Ubiquitin-Proteasome System Stress Sensitizes Ovarian Cancer to Proteasome Inhibitor–Induced Apoptosis
Authors: Bazzaro Martina , Lee Michael K. , Zoso Alessia , Stirling Wanda L.H. , Santillan Antonio , Shih Ie-Ming , Roden Richard B.S.
Published: April 2006

The ubiquitin-proteasome system (UPS) mediates targeted protein degradation. Notably, the UPS determines levels of key checkpoint proteins controlling apoptosis and proliferation by controlling protein half-life. Herein, we show that ovarian carcinoma manifests an overstressed UPS by comparison with normal tissues by accumulation of ubiquitinated proteins despite elevated proteasome levels. Elevated levels of total ubiquitinated proteins and 19S and 20S proteasome subunits are evident in both low-grade and high-grade ovarian carcinoma tissues relative to benign ovarian tumors and in ovarian carcinoma cell lines relative to immortalized surface epithelium. We find that ovarian carcinoma cell lines exhibit greater sensitivity to apoptosis in response to proteasome inhibitors than immortalized ovarian surface epithelial cells. This sensitivity correlates with increased cellular proliferation rate and UPS stress rather than absolute proteasome levels. Proteasomal inhibition in vitro induces cell cycle arrest and the accumulation of p21 and p27 and triggers apoptosis via activation of caspase-3. Furthermore, treatment with the licensed proteasome inhibitor PS-341 slows the growth of ES-2 ovarian carcinoma xenograft in immunodeficient mice. In sum, elevated proliferation and metabolic rate resulting from malignant transformation of the epithelium stresses the UPS and renders ovarian carcinoma more sensitive to apoptosis in response to proteasomal inhibition. (Cancer Res 2006; 66(7): 3754-63)
Silenced Tumor Suppressor Genes Reactivated by DNA Demethylation Do Not Return to a Fully Euchromatic Chromatin State
Authors: McGarvey Kelly M. , Fahrner Jill A. , Greene Eriko , Martens Joost , Jenuwein Thomas , Baylin Stephen B.
Published: April 2006

Histone H3 lysine 9 (H3K9) and lysine 27 (H3K27) trimethylation are properties of stably silenced heterochromatin whereas H3K9 dimethylation (H3K9me2) is important for euchromatic gene repression. In colorectal cancer cells, all of these marks, as well as the key enzymes which establish them, surround the hMLH1 promoter when it is DNA hypermethylated and aberrantly silenced, but are absent when the gene is unmethylated and fully expressed in a euchromatic state. When the aberrantly silenced gene is DNA demethylated and reexpressed following 5-aza-2′-deoxycytidine treatment, H3K9me1 and H3K9me2 are the only silencing marks that are lost. A series of other silenced and DNA hypermethylated gene promoters behave identically even when the genes are chronically DNA demethylated and reexpressed after genetic knockout of DNA methyltransferases. Our data indicate that when transcription of DNA hypermethylated genes is activated in cancer cells, their promoters remain in an environment with certain heterochromatic characteristics. This finding has important implications for the translational goal of reactivating aberrantly silenced cancer genes as a therapeutic maneuver. (Cancer Res 2006; 66(7): 3541-9)
Chemical Enhancers of Cytokine Signaling that Suppress Microfilament Turnover and Tumor Cell Growth
Authors: Park Hyun-Joo , Partridge Emily , Cheung Pam , Pawling Judy , Donovan Rob , Wrana Jeffrey L. , Dennis James W.
Published: April 2006

The transforming growth factor-β (TGF-β) family of cytokines regulates cell proliferation, morphogenesis, and specialized cell functions in metazoans. Herein, we screened a compound library for modifiers of TGF-β signaling in NMuMG epithelial cells using a cell-based assay to measure Smad2/3 nuclear translocation. We identified five enhancers of TGF-β signaling that share a core structure of diethyl 2-(anilinomethylene)malonate (DAM), and D50 values of 1 to 4 μmol/L. Taking advantage of the Mgat5 mutant phenotype of accelerated receptor loss to endocytosis, we determined that DAM-1976 restored the sensitivity of Mgat5−/− carcinoma cells to both TGF-β and epidermal growth factor (EGF). In Mgat5 mutant and wild-type carcinoma cells, DAM-1976 enhanced and prolonged TGF-β- and EGF-dependent Smad2/3 and Erk activation, respectively. DAM-1976 reduced ligand-dependent EGF receptor endocytosis, actin microfilament turnover, and cell spreading, suggesting that the compound attenuates vesicular trafficking. Hyperactivation of intracellular signaling has the potential to suppress tumor cell growth and, in this regard, DAM-1976 represents a new pharmacophore that increases basal activation of Smad2/3 and Erk, inhibits microfilament remodeling, and suppresses carcinoma cell growth. (Cancer Res 2006; 66(7): 3558-66)
Regulation of E-cadherin Expression by VHL and Hypoxia-Inducible Factor
Authors: Esteban Miguel A. , Tran Maxine G.B. , Harten Sarah K. , Hill Peter , Castellanos Maria C. , Chandra Ashish , Raval Raju , O'Brien Tim S. , Maxwell Patrick H.
Published: April 2006

Mutations in von Hippel-Lindau tumor suppressor gene (VHL) underlie the VHL hereditary cancer syndrome and also occur in most sporadic clear cell renal cell cancers (CCRCC). Currently, the mechanism(s) by which VHL loss of function promotes tumor development in the kidney are not fully elucidated. Here, we show that VHL inactivation in precancerous lesions in kidneys from patients with VHL disease correlates with marked down-regulation of the intercellular adhesion molecule E-cadherin. Moreover, in VHL-defective cell lines (RCC4 and RCC10) derived from sporadic CCRCC, reexpression of VHL was found to restore E-cadherin expression. The product of the VHL gene has multiple reported functions, the best characterized of which is its role as the recognition component of an ubiquitin E3 ligase complex responsible for mediating oxygen-dependent destruction of hypoxia-inducible factor-α (HIF-α) subunits. We show that HIF activation is necessary and sufficient to suppress E-cadherin in renal cancer cells. Given the fundamental role of E-cadherin in controlling epithelial behavior, our findings give insight into how VHL inactivation/HIF activation may lead to kidney cancer and also indicate a mechanism by which reduced oxygenation could alter E-cadherin expression in other cancers and influence normal homeostasis in other epithelia. (Cancer Res 2006; 66(7): 3567-75)
Inactivation of Conditional Rb by Villin-Cre Leads to Aggressive Tumors outside the Gastrointestinal Tract
Authors: Kucherlapati Melanie H. , Nguyen Andrew A. , Bronson Roderick T. , Kucherlapati Raju S.
Published: April 2006

We have crossed mice carrying the conditional Rbtm2Brn allele with a constitutive Villin-Cre transgenic mouse. The Villin promoter in these animals is highly expressed in adult intestine and kidney proximal tubules and is expressed in the gut and nephros anlagen during embryogenesis. We report here that these mice develop tumors between 12 and 17 months old outside the gastrointestinal (GI) tract. A high penetrance of pituitary tumors and medullar carcinoma of the thyroid is observed with a lower incidence of hyperplasia of pulmonary neuroendocrine cells and aggressive liver, bile duct, stomach, oral cavity tumors, and lipomas. Rb rearrangement due to ectopic Villin promoter activity in neural crest or neural crest stem cells during embryogenesis is most likely responsible for the medullar carcinoma of the thyroid phenotype. The aggressive nature of the medullar carcinoma of the thyroid and its ability to metastasize to unusual sites make the model suitable for the study of tumor progression and mechanism of metastasis. Observed sites of metastasis include the stomach, small intestine, liver, lung, kidney, pancreas, spleen, bone marrow, salivary gland, fat, lymph nodes, and dorsal root ganglion. Because the Villin promoter is highly active throughout the GI and in the nephros anlagen during development, we find that Rb inactivation is not sufficient to initiate tumorigenesis in the GI or kidneys in mice. (Cancer Res 2006; 66(7): 3576-83)
Estrogen Up-regulates Neuropeptide Y Y1 Receptor Expression in a Human Breast Cancer Cell Line
Authors: Amlal Hassane , Faroqui Somia , Balasubramaniam Ambikaipakan , Sheriff Sulaiman
Published: April 2006

Normal breast tissue mainly expresses the neuropeptide Y (NPY) Y2 receptor whereas primary human breast carcinomas express the Y1 receptor (Y1R) subtype. We hypothesized that activation of estrogen signaling systems plays a role in the induction of Y1R. To investigate this possibility, we used estrogen receptor–positive (ER+) human breast carcinoma cell line, MCF-7, and examined the effect of estrogen on Y1R gene expression and its signaling pathways. Saturation binding studies revealed that MCF-7 cells express high-affinity NPY receptor. NPY inhibited forskolin-stimulated adenosine 3′5′-cyclic monophosphate (cAMP) accumulation and mobilized intracellular Ca2+ in MCF-7 cells. Chronic estrogen treatment enhanced NPY-mediated inhibition of cAMP accumulation by 4-fold and caused a significant increase in Y1R mRNA expression through ERα. Similarly, estrogen increased Y1R mRNA expression in T-47D (ER+) but not in MDA-MB231 or MDA-MB468 (ER−) cell lines. Cycloheximide decreased basal Y1R mRNA expression; however, it did not affect its increase by estrogen. Moreover, estrogen treatment of MCF-7 cells did not increase Y1R mRNA stability. The up-regulation of Y1R expression by estrogen is prevented by hydroxyurea but not by nocodazole or IB-MECA (cell cycle inhibitors). Lastly, NPY inhibited estrogen-induced cell proliferation through Y1R. In conclusion, MCF-7 cells express a functional Y1R coupled to both Ca2+ and cAMP pathways. Estrogen up-regulates Y1R expression through ERα. This effect is independent of increased Y1R mRNA stability or new protein synthesis, and likely occurs during S phase completion of the cell cycle. Estrogen plays an important role in the up-regulation of Y1R, which in turn regulates estrogen-induced cell proliferation in breast cancer cells. (Cancer Res 2006; 66(7): 3706-14)
Selective Inhibition of ErbB2-Overexpressing Breast Cancer In vivo by a Novel TAT-Based ErbB2-Targeting Signal Transducers and Activators of Transcription 3–Blocking Peptide
Authors: Tan Ming , Lan Keng-Hsueh , Yao Jun , Lu Chien-Hsing , Sun Menghong , Neal Christopher L. , Lu Jing , Yu Dihua
Published: April 2006

ErbB2 is an excellent target for cancer therapies. Unfortunately, the outcome of current therapies for ErbB2-positive breast cancers remains unsatisfying due to resistance and side effects. New therapies for ErbB2-overexpressing breast cancers continue to be in great need. Peptide therapy using cell-penetrating peptides (CPP) as peptide carriers is promising because the internalization is highly efficient, and the cargoes delivered can be bioactive. However, the major obstacle in using these powerful CPPs for therapy is their lack of specificity. Here, we sought to develop a peptide carrier that could introduce therapeutics specifically to ErbB2-overexpressing breast cancer cells. By modifying the HIV TAT-derived CPP and conjugating anti-HER-2/neu peptide mimetic (AHNP), we developed the peptide carrier (P3-AHNP) that specifically targeted ErbB2-overexpressing breast cancer cells in vitro and in vivo. A signal transducers and activators of transcription 3 (STAT3)–inhibiting peptide conjugated to this peptide carrier (P3-AHNP-STAT3BP) was delivered more efficiently into ErbB2-overexpressing than ErbB2 low-expressing cancer cells in vitro and successfully decreased STAT3 binding to STAT3-interacting DNA sequence. P3-AHNP-STAT3BP inhibited cell growth in vitro, with ErbB2-overexpressing 435.eB breast cancer cells being more sensitive to the treatment than the ErbB2 low-expressing MDA-MB-435 cells. Compared with ErbB2 low-expressing MDA-MB-435 xenografts, i.p. injected P3-AHNP-STAT3BP preferentially accumulated in 435.eB xenografts, which led to more reduction of proliferation and increased apoptosis and targeted inhibition of tumor growth. This novel peptide delivery system provided a sound basis for the future development of safe and effective new-generation therapeutics to cancer-specific molecular targets. (Cancer Res 2006; 66(7): 3764-72)