bluuebunny/crossref_metadata_2025 huggingface dataset:
NBS1
Is a Prostate Cancer Susceptibility Gene
Authors: Cybulski C. , Górski B. , Dębniak T. , Gliniewicz B. , Mierzejewski M. , Masojć B. , Jakubowska A. , Matyjasik J. , Złowocka E. , Sikorski A. , Narod S. A. , Lubiński J.
Published: September 2005

To evaluate whether an inactivating mutation in the gene for the Nijmegen breakage syndrome (NBS1) plays a role in the etiology of prostate cancer, we compared the prevalence of the 657del5 NBS1 founder allele in 56 patients with familial prostate cancer, 305 patients with nonfamilial prostate cancer, and 1500 control subjects from Poland. Loss of heterozygosity analysis also was performed on DNA samples isolated from 17 microdissected prostate cancers, including 8 from carriers of the 657del5 mutation. The NBS1 founder mutation was present in 5 of 56 (9%) patients with familial prostate cancer (odds ratio, 16; P < 0.0001), 7 of 305 (2.2%) patients with nonfamilial prostate cancer (odds ratio, 3.9; P = 0.01), and 9 of 1500 control subjects (0.6%). The wild-type NBS1 allele was lost in seven of eight prostate tumors from carriers of the 657del5 allele, but loss of heterozygosity was seen in only one of nine tumors from noncarriers (P = 0.003). These findings suggest that heterozygous carriers of the NBS1 founder mutation exhibit increased susceptibility to prostate cancer and that the cancers that develop in the prostates of carriers are functionally homozygous for the mutation.
Monoallelic Methylation of the
APC
Promoter Is Altered in Normal Gastric Mucosa Associated with Neoplastic Lesions
Authors: Clément Geneviève , Bosman Fred T. , Fontolliet Charlotte , Benhattar Jean
Published: September 2005

Adenomatous polyposis coli (APC) promoter hypermethylation has been reported frequently in normal gastric mucosa, but it remained to be clarified whether this occurs in every individual. In this study, methylation of the APC promoter was analyzed in histologically normal-appearing gastric mucosa samples by methylation-sensitive single-strand conformation analysis and by a methylation-sensitive dot blot assay. Epithelial cell samples were collected by microdissection from tissue sections. Equal amounts of methylated and unmethylated APC alleles were found in all gastric mucosa samples from patients without any gastric lesions (20 samples). Allele-specific methylation analysis showed that the methylation of the APC promoter was monoallelic; however, which allele was methylated depended on the cell type. Increased or decreased methylation was found in 10 of 36 (28%) normal gastric mucosa samples adjacent to a gastric or esophageal adenocarcinoma. No allelic loss was found at the APC locus. Modification of the methylation status was also found in 3 of 21 (14%) normal-appearing gastric mucosa samples adjacent to intestinal metaplasia. In contrast, all normal mucosa samples in cases with chronic gastritis but without metaplasia or dysplasia showed a monoallelic methylation pattern. Our results indicate the following: (a) In normal gastric mucosa, the APC promoter shows monoallelic methylation, which is not due to imprinting but most likely due to allelic exclusion; (b) the excluded allele differs between foveolar and glandular epithelial cells; (c) the APC methylation pattern is frequently altered in normal-appearing gastric mucosa of gastric or esophageal adenocarcinoma patients; and (d) such alterations also occur in normal gastric mucosa adjacent to intestinal metaplasia.
Inhibition of gp130 Signaling in Breast Cancer Blocks Constitutive Activation of Stat3 and Inhibits
in Vivo
Malignancy
Authors: Selander Katri S. , Li Li , Watson Latania , Merrell Melinda , Dahmen Heike , Heinrich Peter C. , Müller-Newen Gerhard , Harris Kevin W.
Published: September 2005

The cytokine receptor gp130 is the common signaling subunit of receptors used by the interleukin (IL)-6 cytokine family. gp130 is widely expressed in breast cancer cell lines and primary tumors. The role of gp130 in breast cancer in vivo is unknown. To study the effect of gp130 inhibition in breast cancer, endogenous gp130 signaling in breast cancer cell lines was blocked with a dominant-negative gp130 protein (DN gp130). DN gp130 inhibited constitutive Stat3 activation in breast cancer cells. Both gp130 and epidermal growth factor receptor (EGFR) have been implicated in constitutive Stat3 activation in breast cancer. There are known physical and functional interactions between gp130 and EGFR. Consistent with this, we show that DN gp130 inhibits signaling downstream of the EGFR in breast cancer cells. The effect of DN gp130 on breast cancer in vivo was assessed with an orthotopic nude mouse model. DN gp130 MDA-231 cells had markedly decreased engraftment, size, and metastasis compared with control cells. These results are particularly striking considering that DN gp130-expressing breast cancer cells grow faster in vitro. We hypothesized that DN gp130 expression results in inhibition of invasion and metastasis in vivo. Marked angiogenesis was present in tumors from control animals and was absent in tumors from DN gp130 animals. We additionally show that tissue inhibitor of metalloproteinase-3, an inhibitor of tumor invasion and angiogenesis, is up-regulated in both MDA-231 DN gp130 cells and tumors. These results, in light of the availability of several potential pharmacological inhibitors of gp130, suggest novel approaches to breast cancer therapy.
Predictive Pharmacokinetic-Pharmacodynamic Modeling of Tumor Growth Kinetics in Xenograft Models after Administration of Anticancer Agents
Authors: Simeoni Monica , Magni Paolo , Cammia Cristiano , De Nicolao Giuseppe , Croci Valter , Pesenti Enrico , Germani Massimiliano , Poggesi Italo , Rocchetti Maurizio
Published: September 2005

The available mathematical models describing tumor growth and the effect of anticancer treatments on tumors in animals are of limited use within the drug industry. A simple and effective model would allow applying quantitative thinking to the preclinical development of oncology drugs. In this article, a minimal pharmacokinetic-pharmacodynamic model is presented, based on a system of ordinary differential equations that link the dosing regimen of a compound to the tumor growth in animal models. The growth of tumors in nontreated animals is described by an exponential growth followed by a linear growth. In treated animals, the tumor growth rate is decreased by a factor proportional to both drug concentration and number of proliferating tumor cells. A transit compartmental system is used to model the process of cell death, which occurs at later times. The parameters of the pharmacodynamic model are related to the growth characteristics of the tumor, to the drug potency, and to the kinetics of the tumor cell death. Therefore, such parameters can be used for ranking compounds based on their potency and for evaluating potential differences in the tumor cell death process. The model was extensively tested on discovery candidates and known anticancer drugs. It fitted well the experimental data, providing reliable parameter estimates. On the basis of the parameters estimated in a first experiment, the model successfully predicted the response of tumors exposed to drugs given at different dose levels and/or schedules. It is, thus, possible to use the model prospectively, optimizing the design of new experiments.
Induction of Adipophilin-Specific Cytotoxic T Lymphocytes Using a Novel HLA-A2-Binding Peptide That Mediates Tumor Cell Lysis
Authors: Schmidt Susanne M. , Schag Kerstin , Müller Martin R. , Weinschenk Toni , Appel Silke , Schoor Oliver , Weck Markus M. , Grünebach Frank , Kanz Lothar , Stevanovic Stefan , Rammensee Hans-Georg , Brossart Peter
Published: September 2005

Identification of tumor-associated antigens and advances in tumor immunology resulted in the development of vaccination strategies to treat patients with malignant diseases. Using a novel approach that combines DNA chip analysis of tumor samples with isolation of peptides on the surface of tumor cells, a HLA-A*0201-binding peptide derived from the adipophilin protein was identified. Adipophilin is involved in lipid storage and was thought to be expressed only in adipocytes, but it can be found in other cell types such as macrophages or tumor cells. In the present study, we analyzed the possible use of this peptide as a T-cell epitope presented by malignant cells. To accomplish this, we induced CTL responses using this HLA-A*0201-binding peptide. The in vitro-induced CTLs efficiently lysed cells pulsed with the adipophilin peptide and HLA-matched tumor cell lines in an antigen-specific and HLA-restricted manner. Finally, the induced CTLs recognized autologous dendritic cells (DCs) pulsed with the antigenic peptide or transfected with tumor RNA purified from an adipophilin-expressing tumor cell line. To further analyze the possible use of this peptide in immunotherapies of human malignancies, we induced adipophilin-specific CTLs using peripheral blood mononuclear cells and DCs from HLA-A*0201-positive patients with chronic lymphatic leukemia and plasma cell leukemia. The in vitro-generated CTLs recognized autologous chronic lymphatic leukemia cells and malignant plasma cells, whereas they spared nonmalignant resting or activated B and T lymphocytes, monocytes, or DCs. Our results demonstrate that this peptide might represent an interesting candidate for the development of cancer vaccines designed to target adipophilin-derived epitopes in a wide range of malignancies.
Loss of Vascular Endothelial Growth Factor A Activity in Murine Epidermal Keratinocytes Delays Wound Healing and Inhibits Tumor Formation
Authors: Rossiter Heidemarie , Barresi Caterina , Pammer Johannes , Rendl Michael , Haigh Jody , Wagner Erwin F. , Tschachler Erwin
Published: September 2005

The angiogenic cytokine vascular endothelial growth factor (VEGF)-A plays a central role in both wound healing and tumor growth. In the skin, epidermal keratinocytes are a major source of this growth factor. To study the contribution of keratinocyte-derived VEGF-A to these angiogenesis-dependent processes, we generated mice in which this cytokine was inactivated specifically in keratin 5-expressing tissues. The mutant mice were macroscopically normal, and the skin capillary system was well established, demonstrating that keratinocyte-derived VEGF-A is not essential for angiogenesis in the skin during embryonic development. However, healing of full-thickness wounds in adult animals was appreciably delayed compared with controls, with retarded crust shedding and the appearance of a blood vessel-free zone underneath the newly formed epidermis. When 9,12-dimethyl 1,2-benzanthracene was applied as both tumor initiator and promoter, a total of 143 papillomas developed in 20 of 23 (87%) of control mice. In contrast, only three papillomas arose in 2 of 17 (12%) of the mutant mice, whereas the rest merely displayed epidermal thickening and parakeratosis. Mutant mice also developed only 2 squamous cell carcinomas, whereas 11 carcinomas were found in seven of the control animals. These data demonstrate that whereas keratinocyte-derived VEGF-A is dispensable for skin vascularization under physiological conditions, it plays an important albeit nonessential role during epidermal wound healing and is crucial for the development of 9,12-dimethyl 1,2-benzanthracene-induced epithelial skin tumors.
Potentiation of Tumor Eradication by Adoptive Immunotherapy with T-cell Receptor Gene-Transduced T-Helper Type 1 Cells
Authors: Chamoto Kenji , Tsuji Takemasa , Funamoto Hiromi , Kosaka Akemi , Matsuzaki Junko , Sato Takeshi , Abe Hiroyuki , Fujio Keishi , Yamamoto Kazuhiko , Kitamura Toshio , Takeshima Tsuguhide , Togashi Yuji , Nishimura Takashi
Published: September 2005

Adoptive immunotherapy using antigen-specific T-helper type 1 (Th1) cells has been considered as a potential strategy for tumor immunotherapy. However, its application to tumor immunotherapy has been hampered by difficulties in expanding tumor-specific Th1 cells from tumor-bearing hosts. Here, we have developed an efficient protocol for preparing mouse antigen-specific Th1 cells from nonspecifically activated Th cells after retroviral transfer of T-cell receptor (TCR)-α and TCR-β genes. We demonstrate that Th1 cells transduced with the TCR-α and -β genes from the I-Ad-restricted ovalbumin (OVA)323–339-specific T-cell clone DO11.10 produce IFN-γ but not interleukin-4 in response to stimulation with OVA323–339 peptides or A20 B lymphoma (A20-OVA) cells expressing OVA as a model tumor antigen. TCR-transduced Th1 cells also exhibited cytotoxicity against tumor cells in an antigen-specific manner. Moreover, adoptive transfer of TCR-transduced Th1 cells, but not mock-transduced Th1 cells, exhibited potent antitumor activity in vivo and, when combined with cyclophosphamide treatment, completely eradicated established tumor masses. Thus, TCR-transduced Th1 cells are a promising alternative for the development of effective adoptive immunotherapies.
Modification of Breast Cancer Risk in Young Women by a Polymorphic Sequence in the
egfr
Gene
Authors: Brandt Burkhard , Hermann Silke , Straif Kurt , Tidow Nicola , Buerger Horst , Chang-Claude Jenny
Published: September 2005

The regulation of the epidermal growth factor receptor (egfr) gene in human cancer is not yet fully understood. Recent data on a polymorphic CA repeat located at the 5′-regulatory sequence in intron 1 of the egfr gene [egfr CA simple sequence repeat (SSR) I] point to a possible inheritance of cancer risk associated with the egfr gene. Furthermore, we have detected frequent allelic imbalances restricted to the egfr CA SSR I in breast cancer tissue and nontumorous breast tissue adjacent to invasive and in situ breast cancer representing amplifications. Therefore, we conducted a population-based case-control study to assess the relationship between the egfr polymorphism and breast cancer risk. Cases with a first primary breast cancer by age 50 years and age-matched population controls provided information on known and suspected risk factors. The allelic length of the egfr CA SSR was determined in 616 cases and 1072 population-sampled controls. Genotypes were categorized for analysis by allele length. Multivariate logistic regression was used to compare genotype distributions, accounting for other risk factors, and to investigate gene-environment interactions. We found a modifying effect, albeit no main effect, of the allelic length of the egfr polymorphism on breast cancer risk. The presence of two long alleles (≥19 CA) was associated with a significantly elevated odds ratio (OR) of 10.4 [95% confidence interval (CI), 1.85–58.70] among women with a first-degree family history of breast cancer (P = 0.015 for interaction). The risk increase associated with high red meat consumption (OR, 10.68; 95% CI, 1.57–72.58) and the protective effect of high vegetable intake (OR, 0.07; 95% CI, 0.004–1.07) was also most pronounced among carriers of two long alleles (≥19 CA). The length of the egfr CA SSR may increase the risk for familial breast cancers, and its effect could be modulated by dietary factors.
Enhanced Radiation-Induced Cell Killing and Prolongation of γH2AX Foci Expression by the Histone Deacetylase Inhibitor MS-275
Authors: Camphausen Kevin , Burgan William , Cerra Michael , Oswald Kelli A. , Trepel Jane B. , Lee Min-Jung , Tofilon Philip J.
Published: September 2005

Histone deacetylase (HDAC) inhibitors are undergoing clinical evaluation for cancer therapy. Because HDAC modulates chromatin structure and gene expression, parameters considered to influence radioresponse, we have investigated the effects of the HDAC inhibitor MS-275 on the radiosensitivity of two human tumor cell lines (DU145 prostate carcinoma and U251 glioma). Acetylation status of histones H3 and H4 was determined as a function of time after MS-275 addition to and removal from culture medium. Histone acetylation increased by 6 h after MS-275 addition, reaching a maximum between 24 and 48 h of exposure; providing fresh drug-free medium then resulted in a decrease in histone acetylation that began by 6 h and approached untreated levels by 16 h. Treatment of cells with MS-275 for 48 h followed by irradiation had little or no effect on radiation-induced cell death. However, exposure to MS-275 before and after irradiation resulted in an increase in radiosensitivity with dose enhancement factors of 1.9 and 1.3 for DU145 and U251 cells, respectively. This MS-275 treatment protocol did not result in a redistribution of the cells into a more radiosensitive phase of the cell cycle or in an increase in apoptosis. However, MS-275 did modify the time course of γH2AX expression in irradiated cells. Whereas there was no significant difference in radiation-induced γH2AX foci at 6 h, the number of cells expressing γH2AX foci was significantly greater in the MS-275-treated cells at 24 h after irradiation. These results indicate that MS-275 can enhance radiosensitivity and suggest that this effect may involve an inhibition of DNA repair.
Prolonged Extracellular Signal-Regulated Kinase 1/2 Activation during Fibroblast Growth Factor 1- or Heregulin β1-Induced Antiestrogen-Resistant Growth of Breast Cancer Cells Is Resistant to Mitogen-Activated Protein/Extracellular Regulated Kinase Kinase Inhibitors
Authors: Thottassery Jaideep V. , Sun Yanjie , Westbrook Louise , Rentz Sarah S. , Manuvakhova Marina , Qu Zhican , Samuel Shanti , Upshaw Ramanda , Cunningham Amanda , Kern Francis G.
Published: September 2005

Increased growth factor receptor signaling is implicated in antiestrogen-resistant breast tumors suggesting that abrogation of such signaling could restore or prolong sensitivity to antihormonal agents. Activation of the mitogen-activated protein/extracellular regulated kinase kinase (MEK)-extracellular regulated kinase (ERK)1/2 cascade is a common component of such pathways. We investigated the ability of the MEK activation inhibitor U0126 to block the increased growth of estrogen receptor-positive MCF-7 breast cancer cells caused by fibroblast growth factor 1 (FGF-1), heregulin β1 (HRGβ1), and epidermal growth factor (EGF) in the presence of the pure antiestrogen ICI 182780 (Faslodex; fulvestrant). We found that either FGF-1 or HRGβ1 but not EGF substantially reduced the inhibitory effects of U0126 on growth and ERK1/2 activation, including the combined inhibitory effects of U0126 and ICI 182780. FGF-1 and HRGβ1 also reduced the inhibition of ERK1/2 phosphorylation by the MEK inhibitors PD98059 and PD184161. Interestingly, a transiently transfected dominant-negative MEK1 completely abrogated activation of a coexpressed green fluorescent protein-ERK2 reporter by all three of the factors. Despite a short-lived activation of Ras and Raf-1 by all three of the growth factors, both FGF-1 and HRGβ1, unlike EGF, induced a prolonged activation of MEK and ERK1/2 in these cells. Thus, activation of FGF-1- and HRGβ1-specific signaling causes MEK-dependent prolonged activation of ERK1/2, which is incompletely susceptible to known MEK inhibitors. We also demonstrate that the cytosolic phospholipase A2 inhibitor arachidonyl trifluoro methyl ketone and the pan PKC inhibitor bisindolymaleimide abrogated U0126-resistant phosphorylation of ERK1/2 induced by HRGβ1 but not by FGF-1. Phosphorylation of ERK5 by all three of the factors was also resistant to U0126 suggesting that its activation is not sufficient to overturn growth inhibition due to diminished ERK1/2 activation. Therefore, therapy combining antiestrogens and MEK inhibitors may be ineffective in some antiestrogen-resistant estrogen receptor-positive breast cancers.
Elucidation of Epigenetic Inactivation of
SMAD8
in Cancer Using Targeted Expressed Gene Display
Authors: Cheng Kuang-hung , Ponte Jose F. , Thiagalingam Sam
Published: September 2005

To address the challenge of identifying related members of a large family of genes, their variants and their patterns of expression, we have developed a novel technique known as targeted expressed gene display. Here, we demonstrate the general application of this technique by analyzing the SMAD genes and report that the loss of SMAD8 expression is associated with multiple types of cancers, including 31% of both breast and colon cancers. Epigenetic silencing of SMAD8 expression by DNA hypermethylation in cancers directly correlates with loss of SMAD8 expression. The SMAD8 alteration in a third of breast and colon cancers makes it a significant novel tumor marker as well as a potential therapeutic target. The utility of targeted expressed gene display for the analysis of highly homologous gene families as demonstrated by its application to the SMAD genes suggests that it is an efficient tool for the identification of novel members, simultaneous analysis of differential expression patterns, and initial discovery of alterations of expressed genes.
Protein Kinase C ζ Transactivates Hypoxia-Inducible Factor α by Promoting Its Association with p300 in Renal Cancer
Authors: Datta Kaustubh , Li Jinping , Bhattacharya Resham , Gasparian Levon , Wang Enfeng , Mukhopadhyay Debabrata
Published: September 2005

Hydroxylation at an asparagine residue at the COOH-terminal activation domain of hypoxia-inducible factor (HIF)-1/2 αs is essential for its inactivation under normoxic condition. To date, the mechanism by which HIF-α avoids the inhibitory effect of asparagine hydroxylase in renal cell carcinoma (RCC) in normoxia is undefined. We have shown herein that protein kinase C (PKC) ζ has an important role in HIF-α activation in RCC. By using dominant negative mutant and small interference RNA approaches, we have demonstrated that the association between HIF-α and p300 is modulated by PKCζ. Moreover, a novel signaling pathway involving phosphatidylinositol 3′-kinase and PKCζ has been shown to be responsible for the activation of HIF-α by inhibiting the mRNA expression of FIH-1 (factor inhibiting HIF-1) in RCC and thereby promoting the transcription of hypoxia-inducible genes such as vascular permeability factor/vascular endothelial growth factor.
Bortezomib as a Potential Treatment for Prostate Cancer
Authors: Papandreou Christos N. , Logothetis Christopher J.
Published: September 2005

Androgen ablation and chemotherapy provide effective palliation for most patients with advanced prostate cancer, but eventually progressing androgen-independent prostate cancer threatens the lives of patients usually within a few years, mandating improvement in therapy. Proteasome inhibition has been proposed as a therapy target for the treatment of solid and hematological malignancies. The proteasome is a ubiquitous enzyme complex that is a hub for the regulation of many intracellular regulatory pathways; because of its essential function, this enzyme has become a new target for cancer treatment. Studies with bortezomib (VELCADE, formerly known as PS-341) and other proteasome inhibitors indicate that cancer cells are especially dependent on the proteasome for survival, and several mechanisms used by prostate cancer cells require proteasome function. Bortezomib has been studied extensively in vitro and in vivo, and anticancer activity has been seen in cell and animal models for several solid tumor types, including prostate cancer. A Phase I trial to determine the maximum tolerated dose of once-weekly bortezomib has been completed. This trial included a large fraction of patients with androgen-independent prostate cancer. The maximum tolerated dose was reached at 1.6 mg/m2. A correlation was seen among bortezomib dose, proteasome inhibition, and positive modulation of serum prostate-specific antigen. There was also evidence of down-regulation of serum interleukin 6, a downstream nuclear factor κB effector. This Phase I trial and preclinical studies support additional testing of bortezomib in combination with radiation or chemotherapy for androgen-independent prostate cancer.
An Antiapoptotic Role for Gastrin and the Gastrin/CCK-2 Receptor in Barrett’s Esophagus
Authors: Harris Joseph C. , Clarke Philip A. , Awan Altaf , Jankowski Janusz , Watson Susan A.
Published: September 2005

Mechanisms by which premalignant Barrett’s metaplasia (BM) progresses to esophageal adenocarcinoma are currently being sought. This study investigated the role played by the polypeptide hormone gastrin, specifically its antiapoptotic effects through activation of protein kinase B/Akt (PKB/Akt). In esophageal cell lines with low basal levels of activated PKB/Akt, phosphorylation could be induced by exogenous amidated gastrin. High basal levels of activated PKB/Akt were linked to endogenous gastrin expression and were reduced by treatment with a cholecystokinin-type 2 receptor (CCK-2R) antagonist. Expression of a constitutively active splice variant of the CCK-2R additionally increased basal activation of PKB/Akt. It is proposed that gastrin acting in an autocrine and endocrine manner via a CCK-2R isoform may activate PKB/Akt and that with expression of gastrin and CCK-2R isoforms increasing in BM samples, gastrin may aid progression of BM through amplification of antiapoptotic pathways. Evidence for this proposal was provided through the observed specific up-regulation of PKB/Akt in BM samples.
Hypoxia Increases Heparanase-Dependent Tumor Cell Invasion, Which Can Be Inhibited by Antiheparanase Antibodies
Authors: He Xiaotong , Brenchley Paul E. C. , Jayson Gordon C. , Hampson Lynne , Davies John , Hampson Ian N.
Published: September 2005

The β-endoglucuronidase heparanase plays an important role in tumor invasion, a process that is significantly enhanced by hypoxia. We have used a strategy of stable transfection with antisense to derive ovarian carcinoma cell lines that express different levels of heparanase and used these to demonstrate that invasion correlates with heparanase activity. Secreted heparanase activity was increased by reduction, hypoxia, and growth of cells under reduced oxygen (1%) augmented heparanase activity and invasion, both of which are inhibited by treatment with antiheparanase antibodies. This is the first demonstration that heparanase activity may be regulated by microenvironmental redox conditions, which influence invasion, and that invasion can be blocked with specific heparanase-neutralizing antibodies.
The Tumor Invasion Inhibitor Dihydromotuporamine C Activates RHO, Remodels Stress Fibers and Focal Adhesions, and Stimulates Sodium–Proton Exchange
Authors: McHardy Lianne M. , Sinotte Ryan , Troussard Armelle , Sheldon Claire , Church John , Williams David E. , Andersen Raymond J. , Dedhar Shoukat , Roberge Michel , Roskelley Calvin D.
Published: September 2005

The motuporamines are macrocyclic alkaloids that inhibit tumor cell invasion by an, as yet, unknown mechanism. A structure–activity study recently identified dihydromotuporamine C (dhMotC) as a highly active and readily synthesized analogue. Here, we show that dhMotC causes subtle cytoskeletal alterations in highly invasive MDA231 breast tumor cells that include an increase in the thickness and number of cytoplasmic actin stress fibers. Experiments with serum-starved Swiss 3T3 fibroblasts showed that micromolar concentrations of dhMotC that inhibit tumor cell invasion induce the formation of new stress fibers and large focal adhesion complexes that are dispersed around the entire cell periphery. dhMotC treatment of Swiss 3T3 cells also initiates a strong, long-lived activation of the small GTP-binding protein Rho, and it stimulates Rho kinase-dependent sodium–proton exchanger activity. Liposome-mediated cell loading of C3 exoenzyme prevents dhMotC-mediated Rho activation and stress fiber formation in 3T3 cells. C3 exoenzyme loading also reestablishes elongated MDA231 breast tumor cell invasion in the presence of dhMotC. Taken together, these results indicate that the ability to activate Rho is one important determinant of the anti-invasive activity of dhMotC.
The Role of Metastasis-Associated Protein 1 in Prostate Cancer Progression
Authors: Hofer Matthias D. , Kuefer Rainer , Varambally Sooryanarayana , Li Haojie , Ma Jing , Shapiro Geoffrey I. , Gschwend Juergen E. , Hautmann Richard E. , Sanda Martin G. , Giehl Klaudia , Menke Andre , Chinnaiyan Arul M. , Rubin Mark A.
Published: September 2005

Distinguishing aggressive prostate cancer from indolent disease represents an important clinical challenge, as current therapy requires over treating men with prostate cancer to prevent the progression of a few cases. Expression of the metastasis-associated protein 1 (MTA1) has previously been found to be associated with progression to the metastatic state in various cancers. Analyzing DNA microarray data, we found MTA1 to be selectively overexpressed in metastatic prostate cancer compared with clinically localized prostate cancer and benign prostate tissue. These results were validated by demonstrating overexpression of MTA1 in metastatic prostate cancer by immunoblot analysis. MTA1 protein expression was evaluated by immunohistochemistry in a broad spectrum of prostate tumors with tissue microarrays containing 1940 tissue cores from 300 cases. Metastatic prostate cancer demonstrated significantly higher mean MTA1 protein expression intensity (score = 3.4/4) and percentage of tissue cores staining positive for MTA1 (83%) compared with clinically localized prostate cancer (score = 2.8/4, 63% positive cores) or benign prostate tissue (score = 1.5/4, 25% positive cores) with a mean difference of 0.54 and 1.84, respectively (P < 0.00001 for both). Paradoxically, for localized disease, higher MTA1 protein expression was associated with lower rates of prostate specific antigen recurrence after radical prostatectomy for localized disease. In summary, this study identified an association of MTA1 expression and prostate cancer progression.
Prostate Specific Antigen Expression Is Down-Regulated by Selenium through Disruption of Androgen Receptor Signaling
Authors: Dong Yan , Lee Soo Ok , Zhang Haitao , Marshall James , Gao Allen C. , Ip Clement
Published: September 2005

A previous controlled intervention trial showed that selenium supplementation was effective in reducing the incidence of prostate cancer. Physiological concentrations of selenium have also been reported to inhibit the growth of human prostate cancer cells in vitro. The present study describes the observation that selenium was able to significantly down-regulate the expression of prostate-specific antigen (PSA) transcript and protein within hours in the androgen-responsive LNCaP cells. Decreases in androgen receptor (AR) transcript and protein followed a similar dose and time response pattern upon exposure to selenium. The reduction of AR and PSA expression by selenium occurred well before any significant change in cell number. With the use of a luciferase reporter construct linked to either the PSA promoter or the androgen responsive element, it was found that selenium inhibited the trans-activating activity of AR in cells transfected with the wild-type AR expression vector. Selenium also suppressed the binding of AR to the androgen responsive element site, as evidenced by electrophoretic mobility shift assay of the AR-androgen responsive element complex. In view of the fact that PSA is a well-accepted prognostic indicator of prostate cancer, an important implication of this study is that a selenium intervention strategy aimed at toning down the amplitude of androgen signaling could be helpful in controlling morbidity of this disease.
Induction of Apoptosis and Down-Regulation of Bcl-XL in Cancer Cells by a Novel Small Molecule, 2[ [3-(2,3-Dichlorophenoxy)propyl]amino]ethanol
Authors: Wu Shuhong , Zhu Hongbo , Gu Jian , Zhang Lidong , Teraishi Fuminori , Davis John J. , Jacob Dietmar A. , Fang Bingliang
Published: September 2005

In a search for new anticancer agents, we identified that 2[[3-(2,3-dichlorophenoxy) propyl]amino]ethanol (2,3-DCPE) induced apoptosis more effectively in various cancer cells than in normal human fibroblasts. We further evaluated the cell-killing effects of this compound in vitro in several human cancer cell lines and normal human fibroblasts. A cell viability assay showed that IC50s for human colon cancer cell lines LoVo and DLD-1, for human lung cancer cell lines H1299 and A549, and for normal human fibroblasts were 0.89, 1.95, 2.24, 2.69, and 12.6 μm, respectively. Subsequent studies revealed that 2,3-DCPE could cause cleavage of caspase-8, caspase-3, caspase-9, and poly(ADP-ribose) polymerase and release of cytochrome c in cancer cells but not in normal human fibroblasts. Our data also showed that 2,3-DCPE attenuated the protein level of Bcl-XL and that apoptosis induction by 2,3-DCPE could be blocked by enforced overexpression of Bcl-XL. Our results suggest that 2,3-DCPE might be a potential new anticancer agent.
Significant Differences in the Effects of Magnetic Field Exposure on 7,12-Dimethylbenz(a)anthracene-Induced Mammary Carcinogenesis in Two Substrains of Sprague-Dawley Rats
Authors: Fedrowitz Maren , Kamino Kenji , Löscher Wolfgang
Published: September 2005

We have shown previously (S. Thun-Battersby et al., Cancer Res., 59: 3627–3633, 1999) that power-line frequency (50-Hz) magnetic fields (MFs) at μT-flux densities enhance mammary gland tumor development and growth in the 7,12-dimethylbenz(a)anthracene (DMBA) model of breast cancer in female Sprague-Dawley (SD) rats. We also demonstrated that MF exposure results in an enhanced proliferative activity of the mammary epithelium of SD rats (M. Fedrowitz et al., Cancer Res., 62: 1356–1363, 2002), which is a likely explanation for the cocarcinogenic or tumor-promoting effects of MF exposure in the DMBA model. However, in contrast with our data, in a similar study conducted by Battelle in the United States, no evidence for a cocarcinogenic or tumor-promoting effect of MF exposure was found in the DMBA model in SD rats (L. E. Anderson et al., Carcinogenesis, 20: 1615–1620, 1999). Probably the most important difference between our and the Battelle studies was the use of different substrains of SD rats; the United States rats were much more susceptible to DMBA than the rats used in our studies. This prompted us to compare different substrains of SD outbred rats in our laboratory in respect to MF effects on cell proliferation in the mammary gland, susceptibility to DMBA-induced mammary cancer, and MF effects on mammary tumor development and growth in the DMBA model. The SD substrain (termed “SD1”) used in all of our previous studies was considered MF-sensitive and used for comparison with another substrain (“SD2”) obtained from the same breeder. In contrast with SD1 rats, no enhanced cell proliferation was determined after MF exposure in SD2 rats. MF exposure significantly increased mammary tumor development and growth in SD1 but not SD2 rats. These data indicate that the genetic background plays a pivotal role in effects of MF exposure. Different strains or substrains of rats may serve to evaluate the genetic factors underlying sensitivity to cocarcinogenic or tumor-promoting effects of MF exposure.
Emmprin Promotes Anchorage-Independent Growth in Human Mammary Carcinoma Cells by Stimulating Hyaluronan Production
Authors: Marieb Erica A. , Zoltan-Jones Alexandra , Li Rongsong , Misra Suniti , Ghatak Shibnath , Cao Jian , Zucker Stanley , Toole Bryan P.
Published: September 2005

Emmprin (CD147; basigin) is a plasma membrane glycoprotein, enriched on the surface of many cancer cells, which induces matrix metalloproteinase synthesis via cell-cell interactions. Elevated emmprin production causes increased growth in vivo of human mammary carcinoma cells. In this study, we show that elevation of emmprin expression in less aggressive human carcinoma cells, which normally express low emmprin levels, induces the ability to grow under anchorage-independent conditions. We also found that elevated emmprin expression stimulates hyaluronan production and that the effect of emmprin on anchorage-independent growth is dependent on hyaluronan. Furthermore, emmprin stimulates cell survival pathway signaling in a hyaluronan-dependent manner. From these and other studies we conclude that emmprin enhances several malignant properties of cancer cells, including anchorage-independent growth, invasiveness, and chemoresistance.
Antitumor Activity of 3-Ingenyl Angelate
Authors: Ogbourne Steven M. , Suhrbier Andreas , Jones Brad , Cozzi Sarah-Jane , Boyle Glen M. , Morris Melanie , McAlpine Devi , Johns Jenny , Scott Tania M. , Sutherland Kirsty P. , Gardner Joy M. , Le Thuy T. T. , Lenarczyk Aleksandra , Aylward James H. , Parsons Peter G.
Published: September 2005

Options for skin cancer treatment currently include surgery, radiotherapy, topical chemotherapy, cryosurgery, curettage, and electrodessication. Although effective, surgery is costly and unsuitable for certain patients. Radiotherapy can leave a poor cosmetic effect, and current chemotherapy is limited by low cure rates and extended treatment schedules. Here, we describe the preclinical activity of a novel topical chemotherapeutic agent for the treatment of skin cancer, 3-ingenyl angelate (PEP005), a hydrophobic diterpene ester isolated from the plant Euphorbia peplus. Three daily topical applications of 42 nmol (18 μg) of PEP005 cured a series of s.c. mouse tumors (B16 melanoma, LK2 UV-induced squamous cell carcinoma, and Lewis lung carcinoma; n = >14 tumors/group) and human tumors (DO4 melanoma, HeLa cervical carcinoma, and PC3 and DU145 prostate carcinoma; n = >4 tumors/group) previously established (5–10 mm3) on C57BL/6 or Foxn1nu mice. The treatment produced a mild, short-term erythema and eschar formation but, ultimately, resulted in excellent skin cosmesis. The LD90 for PEP005 for a panel of tumor cell lines was 180–220 μm. Electron microscopy showed that treatment with PEP005 both in vitro (230 μm) and in vivo (42 nmol) rapidly caused swelling of mitochondria and cell death by primary necrosis. 51Cr release, uptake of propidium iodide, and staining with the mitochondria dye JC1, revealed that PEP005 (230 μm) treatment of tumor cells in vitro resulted in a rapid plasma membrane perturbation and loss of mitochondrial membrane potential. PEP005 thus emerges as a new topical anti-skin cancer agent that has a novel mode of action involving plasma membrane and mitochondrial disruption and primary necrosis, ultimately resulting in an excellent cosmetic outcome.
Association of Homozygous Wild-Type Glutathione S-Transferase M1 Genotype with Increased Breast Cancer Risk
Authors: Roodi Nady , Dupont William D. , Moore Jason H. , Parl Fritz F.
Published: September 2005

More than 500 studies have examined the association of the glutathione S-transferase M1 (GSTM1) genotype with various malignancies yielding inconsistent results. The genotyping was based on a PCR assay that identified the GSTM1 null (−/−) genotype but did not distinguish homozygous wild-type (+/+) and heterozygous (+/−) individuals. We developed an assay that allowed the definition of +/+, +/−, and −/− genotypes by separate identification of wild-type and null alleles, which were found with frequencies of 0.225 and 0.775, respectively, in Caucasian women. We applied the new assay to a breast cancer case-control study and identified the +/+ genotype in 14 (6.9%) of 202 control subjects compared with 37 (18.2%) of 203 patients. Compared with women with the −/− genotype, the relative risk of breast cancer for the +/+ genotype was 2.83 (95% confidence interval, 1.45–5.59; P = 0.002), suggesting a protective effect of the GSTM1 deletion.
Rituximab-Dependent Cytotoxicity by Natural Killer Cells
Authors: Dall’Ozzo Sébastien , Tartas Sophie , Paintaud Gilles , Cartron Guillaume , Colombat Philippe , Bardos Pierre , Watier Hervé , Thibault Gilles
Published: September 2005

The FCGR3A gene dimorphism generates two allotypes: FcγRIIIa-158V and FcγRIIIa-158F. The genotype homozygous for FcγRIIIa-158V (VV) is associated with higher clinical response to rituximab, a chimeric anti-CD20 IgG1 used in the treatment of B lymphoproliferative malignancies. Our objective was to determine whether this genetic association relates to rituximab-dependent cytotoxicity mediated by FcγRIIIa/CD16a+ cells. The number of CD16+ circulating monocytes, T cells, and natural killer (NK) cells in 54 donors was first shown to be unrelated to FCGR3A polymorphism. We then demonstrated that FcγRIIIa-158V displays higher affinity for rituximab than FcγRIIIa-158F by comparing rituximab concentrations inhibiting the binding of 3G8 mAb (anti-CD16) with VV NK cells and NK cells homozygous for FcγRIIIa-158F (FF). VV and FF NK cells killed Daudi cells similarly after FcγRIIIa engagement by saturating concentrations of rituximab or 3G8. However, the rituximab concentration resulting in 50% lysis (EC50) observed with NK cells from VV donors was 4.2 times lower than that observed with NK cells from FF donors (on average 0.00096 and 0.00402 μg/ml, respectively, P = 0.0043). Finally, the functional difference between VV and FF NK cells was restricted to rituximab concentrations weakly sensitizing CD20. This study supports the conclusion that FCGR3A genotype is associated with response to rituximab because it affects the relationship between rituximab concentration and NK cell-mediated lysis of CD20+ cells. Rituximab administration could therefore be adjusted according to FCGR3A genotype.
Insulin-Like Growth Factor Binding Protein-3 Interacts with Autocrine Motility Factor/Phosphoglucose Isomerase (AMF/PGI) and Inhibits the AMF/PGI Function
Authors: Mishra Suresh , Raz Avrahram , Murphy Liam J.
Published: September 2005

Autocrine motility factor/phosphoglucose isomerase (AMF/PGI) was identified as a binding partner for insulin-like growth factor binding protein-3 (IGFBP-3) in solubilized T47D and MCF-7 human breast cancer cell membranes. The interaction between AMF/PGI and IGFBP-3 was verified by cross-linking biotinylated IGFBP-3 to intact cells. After solubilization of the membranes, the biotinylated complexes were precipitated with streptavidin-agarose conjugate and analyzed by SDS-PAGE. A Mr ∼80,000 complex was identified when the nitrocellulose membranes were probed either with streptavidin-horseradish peroxidase conjugate or AMF/PGI antiserum confirming the cross-linking of IGFBP-3 to AMF/PGI. The interaction between IGFBP-3 and AMF/PGI was also further confirmed by ligand blotting of purified AMF/PGI using biotinylated IGFBP-3. Both glycosylated and nonglycosylated IGFBP-3 inhibited the catalytic activity of AMF/PGI in a dose-dependent fashion. In addition, IGFBP-3 inhibited the binding of AMF/PGI to breast cancer cells and AMF/PGI-induced migration of both T47D and MCF-7 human breast cancer cells. IGFBP-3 also decreased the phosphorylation of AMF/PGI and reduced the translocation of AMF/PGI to the cell membrane and AMF/PGI. AMF/PGI resulted in a dose-dependent inhibition of IGFBP-3 induced apoptosis in T47D and MCF-7 cells. In summary, we have identified AMF/PGI as a membrane-associated binding partner for IGFBP-3 in breast cancer cells. The ability of IGFBP-3 to bind and inhibit the actions of AMF/PGI may have some role in the antiproliferative proapoptotic effects of IGFBP-3.
Role of the Grb2-Associated Binder 1/SHP-2 Interaction in Cell Growth and Transformation
Authors: Holgado-Madruga Marina , Wong Albert J.
Published: September 2005

Grb2-associated binder 1 (Gab1) is a docking protein that is tyrosine phosphorylated following the activation of multiple cytokine receptors and receptor tyrosine kinases. Its function then is to recruit and activate multiple signaling molecules. In our previous work, we showed that Gab1 enhances cell growth and induces the transformed phenotype in NIH3T3 cells downstream of the epidermal growth factor (EGF) receptor. In this report, we analyze how it produces these effects. Because SHP-2 is the major binding partner of Gab1, we mutated its binding site in the Gab1 cDNA (Gab1/ΔSHP-2). This construct was stably overexpressed in NIH3T3 cells (3T3-Gab1/ΔSHP-2) and in the wild-type Gab1 cDNA (3T3-Gab1) or an empty expression vector (3T3-CTR). Our findings show that after EGF stimulation, Gab1/ΔSHP-2 has a higher level of tyrosine phosphorylation at early time points than Gab1. Gab1/ΔSHP-2 recruits more phosphatidylinositol 3′-kinase than Gab1 after EGF triggering, which accounts for a higher and more sustained AKT activation in 3T3-Gab1/ΔSHP-2 cells relative to 3T3-Gab1 fibroblasts. Moreover, 3T3-Gab1/ΔSHP-2 cells demonstrate a higher level of extracellular-regulated kinase 1 activation at early time points of EGF stimulation. However, there was an unexpected decrease in c-fos promoter induction in 3T3-Gab1/ΔSHP-2 cells when compared with 3T3-Gab1 cells. Additionally, the 3T3-Gab1/ΔSHP-2 cells show a reversion of the transformed phenotype, including fewer morphologic changes, an increase in stress fiber cytoskeletal organization, and a decrease in cell proliferation and anchorage independent growth. These results reveal that the Gab1/SHP-2 interaction is essential for cell growth and transformation but that this must occur through a novel pathway that is independent of extracellular-regulated kinase or AKT. On the basis of its role in growth and transformation, the Gab1/SHP-2 interaction may become an attractive target for the pharmacologic intervention of malignant cell growth.
Caspase-8-Dependent HER-2 Cleavage in Response to Tumor Necrosis Factor α Stimulation Is Counteracted by Nuclear Factor κB through c-FLIP-L Expression
Authors: Benoit Valérie , Chariot Alain , Delacroix Laurence , Deregowski Valérie , Jacobs Nathalie , Merville Marie-Paule , Bours Vincent
Published: September 2005

The oncoprotein HER-2/neu is a prosurvival factor, and its overexpression has been correlated with poor prognosis in patients with breast cancer. We report that HER-2 is a new substrate for caspase-8 and that tumor necrosis factor α (TNF-α) stimulation leads to an early caspase-8-dependent HER-2 cleavage in MCF7 A/Z breast adenocarcinoma cells defective for nuclear factor κB (NFκB) activation. We show that the antiapoptotic transcription factor NFκB counteracts this cleavage through induction of the caspase-8 inhibitor c-FLIP. Our results also demonstrate that this HER-2 cleavage contributes to the TNF-α-induced apoptosis pathway because ectopic expression of an uncleavable HER-2 protects NFκB-defective cells against TNF-α-mediated cell death. Therefore, we propose an original model in which NFκB exerts a new antiapoptotic function by counteracting TNF-α-triggered cleavage of the HER-2 survival factor.
In Vivo
Treatment with CPT-11 Leads to Differentiation of Neuroblastoma Xenografts and Topoisomerase I Alterations
Authors: Santos Alexandre , Calvet Loreley , Terrier-Lacombe Marie-Josee , Larsen Annette , Bénard Jean , Pondarré Corinne , Aubert Geneviève , Morizet Jackie , Lavelle François , Vassal Gilles
Published: September 2005

Topoisomerase I inhibitors, such as CPT-11, are potent anticancer drugs against neuroblastoma (NB). Differentiating agents, such as retinoids, improve the survival of children with metastatic NB. To characterize the biological effects associated with exposure to CPT-11 in vivo, athymic mice bearing a human NB xenograft, named IGR-NB8 and characterized as an immature NB with poor prognostic markers, were treated with CPT-11. Prolonged stable disease was observed, resulting in an overall tumor growth delay of 115 days. During treatment, tumors differentiated into ganglioneuroblastomas (GGNB), which reverted into an immature phenotype when treatment was discontinued. In contrast, 13-cis retinoic acid failed to induce differentiation of IGR-NB8 in vivo. Tumor differentiation was associated with decreased N-myc expression, induction of p73 expression in the perinuclear area and cytoplasm, and a dramatic 35-fold decrease in topoisomerase I (topo I) catalytic activity. The full-length Mr 100,000 topo I protein was present in both pre and post-treatment immature NB xenografts. In contrast, differentiated GGNBs did not contain the Mr 100,000 protein but an intense Mr 48,000 topo I fragment. Furthermore, redistribution of the Mr 48,000 and 68,000 forms to the cytoplasm was observed in differentiated tumors. The same pattern of topo I expression and catalytic activity was observed in NBs and GGNBs obtained from pediatric patients. Our data suggest that prolonged in vivo exposure to CPT-11 induces differentiation of NB xenografts, which is associated with truncation of the topo I enzyme, relocation of the degraded forms to the cytoplasm, and decreased catalytic activity.