bluuebunny/crossref_metadata_2025 huggingface dataset:
Gene Expression Profiles in Pancreatic Intraepithelial Neoplasia Reflect the Effects of Hedgehog Signaling on Pancreatic Ductal Epithelial Cells
Authors: Prasad Nijaguna B. , Biankin Andrew V. , Fukushima Noriyoshi , Maitra Anirban , Dhara Surajit , Elkahloun Abdel G. , Hruban Ralph H. , Goggins Michael , Leach Steven D.
Published: September 2005

Invasive pancreatic cancer is thought to develop through a series of noninvasive duct lesions known as pancreatic intraepithelial neoplasia (PanIN). We used cDNA microarrays interrogating 15,000 transcripts to identify 49 genes that were differentially expressed in microdissected early PanIN lesions (PanIN-1B/2) compared with microdissected normal duct epithelium. In this analysis, a cluster of extrapancreatic foregut markers, including pepsinogen C, MUC6, KLF4, and TFF1, was found to be up-regulated in PanIN. Up-regulation of these genes was further validated using combinations of real-time reverse transcription-PCR, in situ hybridization, and immunohistochemistry in a total of 150 early PanIN lesions from 81 patients. Identification of these gastrointestinal transcripts in human PanIN prompted assessment of other foregut markers by both semiquantitative and real-time reverse transcription-PCR, revealing similar up-regulation of Sox-2, Gastrin, HoxA5, GATA4/5/6, Villin and Forkhead 6 (Foxl1). In contrast to frequent expression of multiple gastric epithelial markers, the intestinal markers intestinal fatty acid binding protein, CDX1 and CDX2 were rarely expressed either in PanIN lesions or in invasive pancreatic cancer. Hedgehog pathway activation induced by transfection of immortalized human pancreatic ductal epithelial cells with Gli1 resulted in up-regulation of the majority of foregut markers seen in early PanIN lesions. These data show frequent up-regulation of foregut markers in early PanIN lesions and suggest that PanIN development may involve Hedgehog-mediated conversion to a gastric epithelial differentiation program.
Cyclooxygenase-2 Inhibits Novel Ginseng Metabolite-Mediated Apoptosis
Authors: Yim Hyung Woo , Jong Hyun-Soon , Kim Tai Young , Choi Hyun Ho , Kim Sang Gyun , Song Sang Hyun , Kim Juyong , Ko Seong-Gyu , Lee Jung Weon , Kim Tae-You , Bang Yung-Jue
Published: September 2005

Recently, a novel intestinal bacterial metabolite of ginseng protopanaxadiol saponins, i.e., 20-O-(β-d-glucopyranosyl)-20(S)-protopanaxadiol (IH-901), has been reported to induce apoptosis in a variety of cancer cells. Here we show a differential effect of IH-901 on several cell types. Exposure to IH-901 for 48 hours at a supposedly subapoptotic concentration of 40 μmol/L led to both apoptotic cell death and G1 arrest in Hep3B cells, but only resulted in G1 arrest in MDA-MB-231, Hs578T, and MKN28 cells. Additionally, the treatment of MDA-MB-231, but not of Hep3B, with IH-901 up-regulated cyclooxygenase-2 (COX-2) mRNA (2 hours) and protein (6 hours), and enhanced the production of prostaglandin E2. In MDA-MB-231 cells, IH-901 induced the sustained activation of extracellular signal-regulated kinase (ERK), whereas inhibition of mitogen-activated protein/ERK kinase blocked IH-901-mediated COX-2 induction and resulted in apoptosis, suggesting the involvement of an ERK-COX-2 pathway. Combined treatment with IH-901 and nonsteroidal anti-inflammatory drugs inhibited COX-2 enzyme and induced apoptosis in MDA-MB-231 and Hs578T cells. Adenovirus-mediated COX-2 small interfering RNAs also effectively inhibited COX-2 protein expression and enhanced IH-901-mediated apoptosis without inhibiting ERK 1/2 phosphorylation, thus providing direct evidence that COX-2 is an antiapoptotic molecule. Moreover, IH-901-mediated G1 arrest resulted from an increase in p27Kip1 mRNA and protein expression followed by a decrease in CDK2 kinase activity that was concurrent with the hypophosphorylation of Rb and p130. In conclusion, IH-901 induced both G1 arrest and apoptosis, and this apoptosis could be inhibited by COX-2 induction.
Combined Targeting of the Estrogen Receptor and the Epidermal Growth Factor Receptor in Non–Small Cell Lung Cancer Shows Enhanced Antiproliferative Effects
Authors: Stabile Laura P. , Lyker Jennifer S. , Gubish Christopher T. , Zhang Weiping , Grandis Jennifer R. , Siegfried Jill M.
Published: September 2005

Identifying new effective therapeutic treatments for lung cancer is critical to improving overall patient survival. We have targeted both the estrogen receptor (ER) and the epidermal growth factor receptor (EGFR) pathways using an ER antagonist, fulvestrant (“Faslodex”), and the selective EGFR tyrosine kinase inhibitor, gefitinib (“Iressa”), in non–small cell lung cancer (NSCLC) cells. Rapid activation of phospho-EGFR and phospho-p44/p42 mitogen-activated protein kinase by estrogen was observed, indicating nonnuclear ER transactivation of EGFR. Additionally, EGFR protein expression was down-regulated in response to estrogen and up-regulated in response to fulvestrant in vitro, suggesting that the EGFR pathway is activated when estrogen is depleted in NSCLC cells. Cell growth and apoptosis were examined in several NSCLC lines that express varying amounts of ERβ, EGFR, and Neu but no full-length ERα. One cell line contained an EGFR mutation. Cells were exposed to 10 nmol/L estrogen and 10 ng/mL EGF and either 1 μmol/L fulvestrant or 1 μmol/L gefitinib alone or in combination. In all cell lines, the drug combination decreased cell proliferation up to 90% and increased apoptosis 2-fold. The relative responses to gefitinib and fulvestrant were similar regardless of ER and EGFR expression and mutation status. In an in vivo lung tumor xenograft model, the drug combination decreased tumor volume in severe combined immunodeficient mice by ∼60% compared with 49% and 32% for gefitinib and fulvestrant treatment alone, respectively. Antitumor effects of the combination therapy were accompanied by biochemical and histologic evidence of increased apoptosis, decreased phospho-p44/p42 mitogen-activated protein kinase expression, and increased Ki-67 expression compared with individual treatment. These studies provide evidence of a functional interaction between the ER and the EGFR pathways in NSCLC.
Administration of IFN-α Enhances the Efficacy of a Granulocyte Macrophage Colony Stimulating Factor–Secreting Tumor Cell Vaccine
Authors: Prell Rodney A. , Li Betty , Lin Jian Min , VanRoey Melinda , Jooss Karin
Published: September 2005

IFN-α is approved for the treatment of multiple cancers. Its pleiotropic properties include inhibition of proliferation and angiogenesis and induction of apoptosis. Type I IFNs also exert immunomodulatory effects, which make it an appropriate candidate to combine with cancer vaccines. The studies reported herein show that 50% of mice reject established B16 tumors following treatment with the combination of a granulocyte macrophage colony-stimulating factor–secreting tumor cell vaccine (B16.GM) and subclinical doses of recombinant murine IFN-α delivered at the vaccine site. Similarly, 80% of mice treated with the combination reject established B16 tumors when recombinant murine IFN-α is given at the challenge site, suggesting that in the latter case its antiproliferative, proapoptotic, and antiangiogenic properties may be involved in controlling tumor growth. In contrast, fewer than 10% of mice reject the tumors when either one is used as a monotherapy. Furthermore, a 30-fold increase in the frequency of melanoma-associated antigen (Trp-2 and gp100) specific T cells was observed in mice treated with the combination when compared with unvaccinated controls. These data show that IFN-α combined with a granulocyte macrophage colony-stimulating factor–secreting tumor cell vaccine significantly enhances vaccine potency and may represent a potential new approach for tumor immunotherapy.
Quantitative Immuno-Positron Emission Tomography Imaging of HER2-Positive Tumor Xenografts with an Iodine-124 Labeled Anti-HER2 Diabody
Authors: Robinson Matthew K. , Doss Mohan , Shaller Calvin , Narayanan Deepa , Marks James D. , Adler Lee P. , González Trotter Dinko E. , Adams Gregory P.
Published: September 2005

Positron emission tomography (PET) provides an effective means of both diagnosing/staging several types of cancer and evaluating efficacy of treatment. To date, the only U.S. Food and Drug Administration–approved radiotracer for oncologic PET is 18F-fluoro-deoxyglucose, which measures glucose accumulation as a surrogate for malignant activity. Engineered antibody fragments have been developed with the appropriate targeting specificity and systemic elimination properties predicted to allow for effective imaging of cancer based on expression of tumor associated antigens. We evaluated a small engineered antibody fragment specific for the HER2 receptor tyrosine kinase (C6.5 diabody) for its ability to function as a PET radiotracer when labeled with iodine-124. Our studies revealed HER2-dependent imaging of mouse tumor xenografts with a time-dependent increase in tumor-to-background signal over the course of the experiments. Radioiodination via an indirect method attenuated uptake of radioiodine in tissues that express the Na/I symporter without affecting the ability to image the tumor xenografts. In addition, we validated a method for using a clinical PET/computed tomography scanner to quantify tumor uptake in small-animal model systems; quantitation of the tumor targeting by PET correlated with traditional necropsy-based analysis at all time points analyzed. Thus, diabodies may represent an effective molecular structure for development of novel PET radiotracers.
Cytoplasmic Domain of proEGF Affects Distribution and Post-Translational Modification of Microtubuli and Increases Microtubule-Associated Proteins 1b and 2 Production in Human Thyroid Carcinoma Cells
Authors: Pyka Janette , Glogowska Aleksandra , Dralle Henning , Hoang-Vu Cuong , Klonisch Thomas
Published: September 2005

We studied the distribution of transcripts encoding the cytoplasmic domain of the membrane-anchored precursor epidermal growth factor (proEGFcyt) and a novel cytoplasmic proEGF splice isoform with a deleted exon 23 and an out-of-frame fusion of exon 24 (proEGFdel23) in human normal and neoplastic thyroid tissues. In papillary thyroid carcinoma (PTC), coexpression of transcripts encoding for both proEGFcyt and proEGFdel23 correlated with poor differentiation of PTC. To determine potential roles of the cytoplasmic proEGF domain in human thyroid cells, we generated stable transfectants of the human follicular thyroid carcinoma cell line FTC-133 overexpressing the normal cytoplasmic domain proEGFcyt, a truncated proEGFcyt composed of the peptide sequence encoded by exons 22 and 23 (proEGF22.23) and proEGFdel23. The proEGFcyt and proEGF22.23 transfectants displayed significantly reduced proliferation rates, an enlarged cellular phenotype, and alterations in the distribution and post-translational modification of the microtubular system. These transfectants also displayed increased production of microtubule-associated proteins 1b and 2c, which was absent in FTC-133-proEGFdel23 or FTC-133-empty plasmid transfectants. This is the first evidence of an involvement of proEGF cytoplasmic domain in microtubular stability in the human thyroid carcinoma cell line FTC-133 and may suggest a specific role for the cytoplasmic domain of membrane-anchored proEGF, particularly exon 23, in thyroid carcinoma. The up-regulation of proEGFdel23 in poorly differentiated PTC and the exclusive detection of both proEGF isoforms in undifferentiated thyroid carcinoma may indicate an involvement of this novel truncated proEGFdel23 cytoplasmic domain during dedifferentiation processes of human thyroid cells.
Two Functional Coding Single Nucleotide Polymorphisms in STK15 (Aurora-A) Coordinately Increase Esophageal Cancer Risk
Authors: Kimura Makoto T. , Mori Takahiro , Conroy Jeffrey , Nowak Norma J. , Satomi Susumu , Tamai Katsuyuki , Nagase Hiroki
Published: September 2005

STK15/Aurora-A is a serine/threonine kinase essential for chromosome segregation and cytokinesis, and is considered to be a cancer susceptibility gene in mice and humans. Two coding single nucleotide polymorphisms in Aurora-A, 91T>A [phenylalanine/isoleucine (F/I)] and 169G>A [valine/isoleucine (V/I)], create four haplotypes, 91T-169G, 91A-169G, 91T-169A, and 91A-169A. We evaluated the association between these coding single nucleotide polymorphisms and esophageal cancer risk by genotyping 197 esophageal cancer cases and 146 controls. Haplotype 91A-169A (I31/I57) was observed to be statistically more frequent in cancer cases (odds ratio, 3.1452; 95% confidence interval, 1.0258-9.6435). Functional differences among the four isoforms were then analyzed to reveal the source of the cancer risk. Kinase activity levels of I31/I57 and F31/I57 were reduced to 15% and 40% compared with I31/V57 in vivo and in vitro. We considered the differences between the kinase activities and divided individuals into four categories of Aurora-A haplotype combination. Category I had 57.5% or less kinase activity compared with the most common category, category III, and had a significantly higher estimated cancer risk (odds ratio, 5.5328; 95% confidence interval, 1.8149-16.8671). Abnormal nuclear morphology, a characteristic of genomic instability, was observed to be 30 to 40 times more frequent in human immortalized fibroblast cells overexpressing I31/I57 or F31/I57 compared with the others. Furthermore, significantly higher levels of chromosomal instability were observed in cancers in category I (homozygote 91T-169A) than those in category III (homozygous 91A-169G). These results indicate that the less kinase active Aurora-A haplotype combinations might induce genomic instability and increase esophageal cancer risk either in a recessive or a dominant manner.
The Role of Hypoxia-Inducible Factor-1 in Three-dimensional Tumor Growth, Apoptosis, and Regulation by the Insulin-Signaling Pathway
Authors: Leek Russell D. , Stratford Ian , Harris Adrian L.
Published: September 2005

The purpose of this study was to establish the effect of hypoxia-inducible factor-1 (HIF-1) directly on tumor growth, independently of angiogenesis. This was done by growing wild-type mouse hepatoma cells (HEPA-1) and their HIF-1–deficient counterpart C4 as multicellular tumor spheroids and quantifying differences in growth rates and proliferative and apoptotic indices. Insulin and insulin-like growth factor-I are key growth factors, also able to regulate hypoxia-responsive genes via HIF-1; thus, the effects of insulin on this model were also investigated. Two-dimensional growth was serum dependent and no difference was seen between wild-type HEPA-1 and C4 cell growth profiles, but major differences were seen in three-dimensional growth. HIF-1 supported spheroid growth under hypoxia as the HEPA-1 spheroids grew faster than the C4. Surprisingly, the HIF-1–deficient cells had a higher proliferation rate in three-dimensional growth (C4 mean S-phase index, 13.6%; HEPA-1 mean S-phase index, 9%; P = 0.009) that was associated with an inhibition of apoptosis. However, the apoptosis rate was much greater in these spheroids (C4 mean apoptotic index, 6.4; HEPA-1 mean apoptotic index, 0.78%; P = 0.0006). Addition of insulin increased proliferation and apoptosis in both HEPA-1 and C4 spheroids, demonstrating an HIF-1–independent effect of insulin signaling in three-dimensional growth. These results indicate that the enhancing effect of HIF-1 in three-dimensional tumor growth is a balance of both reduced proliferation and enhanced survival, the latter being proportionally greater.
Identification of the Genes Involved in Enhanced Fenretinide-Induced Apoptosis by Parthenolide in Human Hepatoma Cells
Authors: Park Jeong-Hyang , Liu Lan , Kim In-Hee , Kim Jong-Hyun , You Kyung-Ran , Kim Dae-Ghon
Published: September 2005

Fenretinide (N-4-hydroxyphenyl retinamide, 4HPR) is a synthetic anticancer retinoid that is a well-known apoptosis-inducing agent. Recently, we observed that the apoptosis induced by fenretinide could be effectively enhanced in hepatoma cells by a concomitant treatment with parthenolide, which is a known inhibitor of nuclear factor-κB (NF-κB). Furthermore, treatment with fenretinide triggered the activation of NF-κB during apoptosis, which could be substantially inhibited by parthenolide, suggesting that NF-κB activation during fenretinide-induced apoptosis has an antiapoptotic effect. This study investigated the molecular mechanism of this apoptotic potentiation by NF-κB inhibition. The genes involved in the enhanced fenretinide-induced apoptosis by parthenolide were identified using the differential display-PCR method and subsequent Northern blot or semiquantitative reverse transcriptase PCR analysis. This study identified 35 apoptosis-related genes including 12 unknown genes that were either up- or down-regulated by parthenolide. Interestingly, one up-regulated gene (HA1A2) was isolated and cloned from the liver cDNA, and was found to be identical to ANKRD1, which is also referred to as the CARP gene. Compared with controls treated with an empty vector or with antisense cDNA, the ectopic expression of ANKRD1 led to reduced colony formation and to enhanced apoptotic cell death in hepatoma cells. These results suggest that ANKRD1 and the other genes, whose expressions were substantially modulated by the parthenolide-mediated inhibition of NF-κB activation, play roles in the enhanced drug-induced apoptosis. In addition, this study suggests that those identified genes may be useful in anticancer strategies against hepatoma.
RET-Familial Medullary Thyroid Carcinoma Mutants Y791F and S891A Activate a Src/JAK/STAT3 Pathway, Independent of Glial Cell Line–Derived Neurotrophic Factor
Authors: Plaza Menacho Ivan , Koster Roelof , van der Sloot Almer M. , Quax Wim J. , Osinga Jan , van der Sluis Tineke , Hollema Harry , Burzynski Grzegorz M. , Gimm Oliver , Buys Charles H.C.M. , Eggen Bart J.L. , Hofstra Robert M.W.
Published: September 2005

The RET proto-oncogene encodes a receptor tyrosine kinase whose dysfunction plays a crucial role in the development of several neural crest disorders. Distinct activating RET mutations cause multiple endocrine neoplasia type 2A (MEN2A), type 2B (MEN2B), and familial medullary thyroid carcinoma (FMTC). Despite clear correlations between the mutations found in these cancer syndromes and their phenotypes, the molecular mechanisms connecting the mutated receptor to the different disease phenotypes are far from completely understood. Luciferase reporter assays in combination with immunoprecipitations, and Western and immunohistochemistry analyses were done in order to characterize the signaling properties of two FMTC-associated RET mutations, Y791F and S891A, respectively, both affecting the tyrosine kinase domain of the receptor. We show that these RET-FMTC mutants are monomeric receptors which are autophosphorylated and activated independently of glial cell line–derived neurotrophic factor. Moreover, we show that the dysfunctional signaling properties of these mutants, when compared with wild-type RET, involve constitutive activation of signal transducers and activators of transcription 3 (STAT3). Furthermore, we show that STAT3 activation is mediated by a signaling pathway involving Src, JAK1, and JAK2, differing from STAT3 activation promoted by RETC634R which was previously found to be independent of Src and JAKs. Three-dimensional modeling of the RET catalytic domain suggested that the structural changes promoted by the respective amino acids substitutions lead to a more accessible substrate and ATP-binding monomeric conformation. Finally, immunohistochemical analysis of FMTC tumor samples support the in vitro data, because nuclear localized, Y705-phosphorylated STAT3, as well as a high degree of RET expression at the plasma membrane was observed.
Coadministration of Histone Deacetylase Inhibitors and Perifosine Synergistically Induces Apoptosis in Human Leukemia Cells through Akt and ERK1/2 Inactivation and the Generation of Ceramide and Reactive Oxygen Species
Authors: Rahmani Mohamed , Reese Erin , Dai Yun , Bauer Cheryl , Payne Shawn G. , Dent Paul , Spiegel Sarah , Grant Steven
Published: September 2005

Interactions between histone deacetylase inhibitors (HDACIs) and the alkyl-lysophospholipid perifosine were examined in human leukemia cells. Coadministration of sodium butyrate, suberoylanilide hydroxamic acid (SAHA), or trichostatin with perifosine synergistically induced mitochondrial dysfunction (cytochrome c and apoptosis-inducing factor release), caspase-3 and -8 activation, apoptosis, and a marked decrease in cell growth in U937 as well as HL-60 and Jurkat leukemia cells. These events were associated with inactivation of extracellular signal-regulated kinase (ERK) 1/2 and Akt, p46 c-jun-NH2-kinase (JNK) activation, and a pronounced increase in generation of ceramide and reactive oxygen species (ROS). They were also associated with up-regulation of Bak and a marked conformational change in Bax accompanied by membrane translocation. Ectopic expression of Bcl-2 delayed but was ultimately ineffective in preventing perifosine/HDACI-mediated apoptosis. Enforced expression of constitutively active mitogen-activated protein kinase kinase (MEK) 1 or myristoylated Akt blocked HDACI/perifosine-mediated ceramide production and cell death, suggesting that MEK/ERK and Akt inactivation play a primary role in these phenomena. However, inhibition of JNK activation (e.g., by the JNK inhibitor SP600125) did not attenuate sodium butyrate/perifosine-induced apoptosis. In addition, the free radical scavenger N-acetyl-l-cysteine attenuated ROS generation and apoptosis mediated by combined treatment. Finally, the acidic sphingomyelinase inhibitor desipramine attenuated HDACI/perifosine-mediated ceramide and ROS production as well as cell death. Together, these findings indicate that coadministration of HDACIs with perifosine in human leukemia cells leads to Akt and MEK/ERK disruption, a marked increase in ceramide and ROS production, and a striking increase in mitochondrial injury and apoptosis. They also raise the possibility that combining these agents may represent a novel antileukemic strategy.
Methylenetetrahydrofolate Reductase Polymorphisms and Therapy Response in Pediatric Acute Lymphoblastic Leukemia
Authors: Aplenc Richard , Thompson Jennifer , Han Peggy , La Mei , Zhao Huaqing , Lange Beverly , Rebbeck Timothy
Published: September 2005

A significant portion of patients treated for pediatric acute lymphoblastic leukemia (ALL) relapse. We hypothesized that common polymorphisms with moderate effect sizes and large attributive risks could explain an important fraction of ALL relapses. Methylenetetrahydrofolate reductase (MTHFR) is central to folate metabolism and has two common functional polymorphisms (C677T and A1298G). Methotrexate (MTX), which interrupts folate metabolism, is a mainstay of pediatric ALL therapy. MTX inhibits the synthesis of dTMP needed for DNA replication by blocking the conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate by MTHFR. We hypothesized that a deactivating MTHFR allele would increase ALL relapse risk by potentially increasing 5,10-methylenetetrahydrofolate and dTMP, enhancing DNA synthesis and thus opposing MTX. To test this hypothesis, we genotyped 520 patients on the Children's Cancer Study Group ALL study, CCG-1891. The MTHFR C677T variant allele was statistically significantly associated with relapse (χ2 = 4.38, P = 0.036). This association remained significant (hazard ratio = 1.82, P = 0.008), controlling for important covariates, and was more predictive of relapse than other predictors, including day 7 bone marrow response. The MTHFR C677T variant allele was not associated with an increased risk of toxicity or infection. The MTHFR A1298G polymorphism was not associated with altered risks of relapse, toxicity, or infection. Haplotype analysis showed six common haplotypes that did not provide additional information predictive for relapse. These data provide evidence that the MTHFR C677T polymorphism is a common genetic variant conferring a moderate relative risk and a high attributable risk for relapse in pediatric ALL patients.
Survivin-Responsive Conditionally Replicating Adenovirus Exhibits Cancer-Specific and Efficient Viral Replication
Authors: Kamizono Junichi , Nagano Satoshi , Murofushi Yoshiteru , Komiya Setsuro , Fujiwara Hisayoshi , Matsuishi Toyojiro , Kosai Ken-ichiro
Published: September 2005

Although a conditionally replicating adenovirus (CRA) exhibiting cancer-selective replication and induction of cell death is an innovative potential anticancer agent, current imperfections in cancer specificity and efficient viral replication limit the usefulness of this technique. Here, we constructed survivin-responsive CRAs (Surv.CRAs), in which expression of the wild-type or mutant adenoviral early region 1A (E1A) gene is regulated by the promoter of survivin, a new member of the inhibitor of apoptosis gene family. We explored the cancer specificity and effectiveness of viral replication of Surv.CRAs, evaluating their potential as a treatment for cancer. The survivin promoter was strongly activated in all cancers examined at levels similar to or even higher than those seen for representative strong promoters; in contrast, low activity was observed in normal cells. Surv.CRAs efficiently replicated and potently induced cell death in most types of cancer. In contrast, minimal viral replication in normal cells did not induce any detectable cytotoxicity. A single injection of Surv.CRAs into a preestablished tumor expressing survivin, even at relatively low levels, induced significant tumor death and inhibition of tumor growth. Furthermore, Surv.CRAs were superior to telomerase-dependent CRAs, one of the most effective CRAs that have been examined to date, both in terms of cancer specificity and efficiency. Thus, Surv.CRAs are an attractive potential anticancer agent that could effectively and specifically treat a variety of cancers.
Enhancement of Folate Receptor α Expression in Tumor Cells Through the Glucocorticoid Receptor: A Promising Means to Improved Tumor Detection and Targeting
Authors: Tran Thuyet , Shatnawi Aymen , Zheng Xuan , Kelley Karen M.M. , Ratnam Manohar
Published: September 2005

The utility of the folate receptor (FR) type α, in a broad range of targeted therapies and as a diagnostic serum marker in cancer, is confounded by its variable tumor expression levels. FR-α, its mRNA and its promoter activity were coordinately up-regulated by the glucocorticoid receptor (GR) agonist, dexamethasone. Optimal promoter activation which occurred at <50 nmol/L dexamethasone was inhibited by the GR antagonist, RU486, and was enhanced by coactivators, supporting GR mediation of the dexamethasone effect. The dexamethasone response of the FR-α promoter progressed even after dexamethasone was withdrawn, but this delayed effect required prior de novo protein synthesis indicating an indirect regulation. The dexamethasone effect was mediated by the G/C-rich (Sp1 binding) element in the core P4 promoter and was optimal in the proper initiator context without associated changes in the complement of major Sp family proteins. Histone deacetylase (HDAC) inhibitors potentiated dexamethasone induction of FR-α independent of changes in GR levels. Dexamethasone/HDAC inhibitor treatment did not cause de novo FR-α expression in a variety of receptor-negative cells. In a murine HeLa cell tumor xenograft model, dexamethasone treatment increased both tumor-associated and serum FR-α. The results support the concept of increasing FR-α expression selectively in the receptor-positive tumors by brief treatment with a nontoxic dose of a GR agonist, alone or in combination with a well-tolerated HDAC inhibitor, to increase the efficacy of various FR-α–dependent therapeutic and diagnostic applications. They also offer a new paradigm for cancer diagnosis and combination therapy that includes altering a marker or a target protein expression using general transcription modulators.
Matrix Metalloproteinases 9 and 10 Inhibit Protein Kinase C–Potentiated, p53-Mediated Apoptosis
Authors: Meyer Eric , Vollmer Jean-Yves , Bovey Raymonde , Stamenkovic Ivan
Published: September 2005

p53, a major sensor of DNA damage, is a transcription factor that, depending on its phosphorylation status, regulates the cell cycle, DNA repair, or apoptosis. The protein kinase C (PKC) family of isozymes is also implicated in cell cycle and programmed cell death (PCD) control and has recently been shown to influence p53 function. Using three human colon adenocarcinoma cell lines SW480, EB-1, and HCT116 that either lack p53 function and were engineered to express inducible wild-type p53 (wt p53), or that constitutively express wt p53, we show that phorbol ester–mediated PKC activation potentiates p53-induced PCD. Despite the effectiveness of PKC/p53 synergy in inducing SW480 tumor cell death, however, a fraction of the cells invariably survive. To address the putative mechanisms that underlie resistance to PKC/p53-induced cell death, we generated a phorbol 12-myristate 13-acetate/p53–resistant SW480 subline and compared the gene expression profile of resistant and parental cells by DNA microarray analysis. The results of these experiments show that PKC/p53-resistant cells express a higher level of several matrix metalloproteinases (MMP), including MMP-9, MMP-10, and MMP-12, and corresponding real-time PCR assays indicate that p53 is a negative regulator of MMP-9 gene expression. Using MMP inhibitors and MMP-specific small interfering RNA, we show that MMP function confers protection from PKC/p53-induced apoptosis and identify the protective MMPs as MMP-9 and MMP-10. Taken together, these observations provide evidence that MMPs are implicated in tumor cell resistance to the synergistic proapoptotic effect of PKC and p53.
Distal Chr 4 Harbors a Genetic Locus (Gct1) Fundamental for Spontaneous Ovarian Granulosa Cell Tumorigenesis in a Mouse Model
Authors: Dorward Ann M. , Shultz Kathryn L. , Horton Lindsay G. , Li Renhua , Churchill Gary A. , Beamer Wesley G.
Published: September 2005

The spontaneous development of juvenile-onset ovarian granulosa cell tumors in mice of the SWXJ-9 recombinant inbred strain is a model for juvenile-type granulosa cell tumors that appear in very young girls. To expedite gene discovery in this mouse model of childhood cancer, we did a gene mapping study with the SWXJ-9 recombinant inbred strain and the evolutionarily divergent Mus musculus castaneus (CAST/Ei) strain as a mapping partner. Our mapping strategy focused on autosomal determinants of susceptibility with a backcross scheme that exploited a paternal, parent-of-origin effect for a X-linked gene (Gct4) that strongly supports granulosa cell tumor development. Of 1,968 backcross females examined, we detected 81 granulosa cell tumor-bearing animals and compared their allelic inheritance patterns to non-tumor-bearing siblings in a case-control analysis. The results of our study have confirmed an important locus on mouse chromosome (Chr) 4 (Gct1) and have revealed new loci for granulosa cell tumor susceptibility (Gct7-Gct9) on Chrs 1, 2, and 13 with susceptibility alleles contributed by the SWXJ-9 progenitor. Two novel gene-gene interactions supportive for granulosa cell tumor development were also observed between loci on Chrs 17 and 18 and loci on Chrs 2 and 10. Our data substantiate the evidence that Gct1 on Chr 4 is a fundamental oncogene for granulosa cell tumorigenesis in mice and has identified additional interacting autosomal loci that support tumor development.
The Tumor Bed Effect: Increased Metastatic Dissemination from Hypoxia-Induced Up-regulation of Metastasis-Promoting Gene Products
Authors: Rofstad Einar K. , Mathiesen Berit , Henriksen Kristin , Kindem Kristil , Galappathi Kanthi
Published: September 2005

Cancer patients with recurrent local disease after radiation therapy have increased probability of developing regional and distant metastases. The mechanisms behind this observation were studied in the present work by using D-12 and R-18 human melanoma xenografts growing in preirradiated beds in BALB/c-nu/nu mice as preclinical models of recurrent primary tumors in humans. D-12 tumors metastasize to the lungs, whereas R-18 tumors develop lymph node metastases. Based on earlier studies, we hypothesized that metastasis was governed primarily by the proangiogenic factor interleukin-8 (IL-8) in D-12 tumors and by the invasive growth-promoting receptor urokinase-type plasminogen activator receptor (uPAR) in R-18 tumors. Pimonidazole was used as a hypoxia marker, and hypoxia, microvascular hotspots, and the expression of IL-8 and uPAR were studied by immunohistochemistry. The metastatic frequency was significantly higher in tumors in preirradiated beds than in control tumors in unirradiated beds, and it increased with the preirradiation dose. D-12 tumors showed increased fraction of hypoxic cells, increased fraction of IL-8–positive cells, and increased density of microvascular hotspots in preirradiated beds, and R-18 tumors showed increased fraction of hypoxic cells and increased fraction of uPAR-positive cells in preirradiated beds. Strong correlations were found between these parameters and metastatic frequency. IL-8 was up-regulated in hypoxic regions of D-12 tumors, and uPAR was up-regulated in hypoxic regions of R-18 tumors. Daily treatment with anti–IL-8 antibody (D-12) or anti-uPAR antibody (R-18) suppressed metastasis significantly. Our preclinical study suggests that primary tumors recurring after inadequate radiation therapy may show increased metastatic propensity because of increased fraction of hypoxic cells and hypoxia-induced up-regulation of metastasis-promoting gene products. Two possible mechanisms were identified: hypoxia may enhance metastasis by inducing neoangiogenesis facilitating hematogenous spread and by promoting invasive growth facilitating lymphogenous spread. The aggressive behavior of postirradiation local recurrences suggests that they should be subjected to curative treatment as early as possible to prevent further metastatic dissemination. Moreover, the possibility that patients with a high probability of developing local recurrences after radiation therapy may benefit from postirradiation treatment with antiangiogenic and/or anti-invasive agents merits clinical investigation.
Histone Deacetylase Inhibitor Valproic Acid Enhances the Cytokine-Induced Expansion of Human Hematopoietic Stem Cells
Authors: De Felice Lidia , Tatarelli Caterina , Mascolo Maria Grazia , Gregorj Chiara , Agostini Francesca , Fiorini Roberto , Gelmetti Vania , Pascale Simona , Padula Fabrizio , Petrucci Maria Teresa , Arcese William , Nervi Clara
Published: September 2005

Ex vivo amplification of human hematopoietic stem cells (HSC) without loss of their self-renewing potential represents an important target for transplantation, gene and cellular therapies. Valproic acid is a safe and widely used neurologic agent that acts as a potent inhibitor of histone deacetylase activities. Here, we show that valproic acid addition to liquid cultures of human CD34+ cells isolated from cord blood, mobilized peripheral blood, and bone marrow strongly enhances the ex vivo expansion potential of different cytokine cocktails as shown by morphologic, cytochemical, immunophenotypical, clonogenic, and gene expression analyses. Notably, valproic acid highly preserves the CD34 positivity after 1 week (range, 40-89%) or 3 weeks (range, 21-52%) amplification cultures with two (Flt3L + thrombopoietin) or four cytokines (Flt3L + thrombopoietin + stem cell factor + interleukin 3). Moreover, valproic acid treatment increases histone H4 acetylation levels at specific regulatory sites on HOXB4, a transcription factor gene with a key role in the regulation of HSC self-renewal and AC133, a recognized marker gene for stem cell populations. Overall, our results relate the changes induced by valproic acid on chromatin accessibility with the enhancement of the cytokine effect on the maintenance and expansion of a primitive hematopoietic stem cell population. These findings underscore the potentiality of novel epigenetic approaches to modify HSC fate in vitro.
BRCA2 Regulates Homologous Recombination in Response to DNA Damage: Implications for Genome Stability and Carcinogenesis
Authors: Abaji Christine , Cousineau Isabelle , Belmaaza Abdellah
Published: September 2005

BRCA2 has been implicated in the maintenance of genome stability and RAD51-mediated homologous recombination repair of chromosomal double-strand breaks (DSBs), but its role in these processes is unclear. To gain more insight into its role in homologous recombination, we expressed wild-type BRCA2 in the well-characterized BRCA2-deficient human cell line CAPAN-1 containing, as homologous recombination substrates, either direct or inverted repeats of two inactive marker genes. Whereas direct repeats monitor a mixture of RAD51-dependent and RAD51-independent homologous recombination events, inverted repeats distinguish between these events by reporting RAD51-dependent homologous recombination, gene conversion, and crossover events only. At either repeats, BRCA2 decreases the rate and frequency of spontaneous homologous recombination, but following chromosomal DSBs, BRCA2 increases the frequency of homologous recombination. At direct repeats, BRCA2 suppresses both spontaneous gene conversion and deletions, which can arise either from crossover or RAD51-independent sister chromatid replication slippage (SCRS), but following chromosomal DSBs, BRCA2 highly promotes gene conversion with little effect on deletions. At inverted repeats, spontaneous or DSB-induced crossover events were scarce and BRCA2 does not suppress their formation. From these results, we conclude that (i) BRCA2 regulates RAD51 recombination in response to the type of DNA damage and (ii) BRCA2 suppresses SCRS, suggesting a role for BRCA2 in sister chromatids cohesion and/or alignment. Loss of such control in response to estrogen-induced DNA damage after BRCA2 inactivation may be a key initial event triggering genome instability and carcinogenesis.
Gene Expression Profile of Papillary Thyroid Cancer: Sources of Variability and Diagnostic Implications
Authors: Jarząb Barbara , Wiench Małgorzata , Fujarewicz Krzysztof , Simek Krzysztof , Jarząb Michał , Oczko-Wojciechowska Małgorzata , Włoch Jan , Czarniecka Agnieszka , Chmielik Ewa , Lange Dariusz , Pawlaczek Agnieszka , Szpak Sylwia , Gubała Elżbieta , Świerniak Andrzej
Published: September 2005

The study looked for an optimal set of genes differentiating between papillary thyroid cancer (PTC) and normal thyroid tissue and assessed the sources of variability in gene expression profiles. The analysis was done by oligonucleotide microarrays (GeneChip HG-U133A) in 50 tissue samples taken intraoperatively from 33 patients (23 PTC patients and 10 patients with other thyroid disease). In the initial group of 16 PTC and 16 normal samples, we assessed the sources of variability in the gene expression profile by singular value decomposition which specified three major patterns of variability. The first and the most distinct mode grouped transcripts differentiating between tumor and normal tissues. Two consecutive modes contained a large proportion of immunity-related genes. To generate a multigene classifier for tumor-normal difference, we used support vector machines-based technique (recursive feature replacement). It included the following 19 genes: DPP4, GJB3, ST14, SERPINA1, LRP4, MET, EVA1, SPUVE, LGALS3, HBB, MKRN2, MRC2, IGSF1, KIAA0830, RXRG, P4HA2, CDH3, IL13RA1, and MTMR4, and correctly discriminated 17 of 18 additional PTC/normal thyroid samples and all 16 samples published in a previous microarray study. Selected novel genes (LRP4, EVA1, TMPRSS4, QPCT, and SLC34A2) were confirmed by Q-PCR.Our results prove that the gene expression signal of PTC is easily detectable even when cancer cells do not prevail over tumor stroma. We indicate and separate the confounding variability related to the immune response. Finally, we propose a potent molecular classifier able to discriminate between PTC and nonmalignant thyroid in more than 90% of investigated samples.
Inhibitory Anti-FLT3 Antibodies Are Capable of Mediating Antibody-Dependent Cell-Mediated Cytotoxicity and Reducing Engraftment of Acute Myelogenous Leukemia Blasts in Nonobese Diabetic/Severe Combined Immunodeficient Mice
Authors: Piloto Obdulio , Levis Mark , Huso David , Li Yiwen , Li Hongli , Wang Mei-Nai , Bassi Rajiv , Balderes Paul , Ludwig Dale L. , Witte Larry , Zhu Zhenping , Hicklin Daniel J. , Small Donald
Published: September 2005

Aberrant FLT3 expression and/or mutation plays a significant role in leukemogenesis. This has prompted the development of selective small molecule tyrosine kinase inhibitors against FLT3. However, like most tyrosine kinase inhibitors, those against FLT3 are not completely specific and at the doses required to completely inhibit target, significant toxicities may occur. In addition, tyrosine kinase inhibitors for other kinases have been shown to select for cells that become resistant. To overcome some of these limitations we developed two fully human phage display monoclonal antibodies against FLT3 (IMC-EB10 and IMC-NC7). These antibodies inhibited ligand-mediated activation of wild-type FLT3 and constitutively activated mutant FLT3 and in most cell types affected downstream STAT5, AKT, and mitogen-activated protein kinase activation. In addition to interfering with FLT3 signaling, IMC-EB10 and, to a significantly lesser extent, IMC-NC7 initiated antibody-dependent cell-mediated cytotoxicity on FLT3-expressing cells. When IMC-EB10 was used in vivo to treat nonobese diabetic/severe combined immunodeficient mice given injections of primary FLT3/ITD acute myelogenous leukemia samples or myeloid cell lines with FLT3 expression, it significantly decreased engraftment of leukemic cells and increased survival, respectively. In contrast, IMC-EB10 treatment did not reduce engraftment of normal human CD34+ cord blood cells nor did it show any significant inhibition of normal murine hematopoiesis. Thus, these types of antibodies have the potential to be safe and effective new therapeutic agents for acute myelogenous leukemia and possibly other FLT3-expressing malignancies.
Jasmonates: Novel Anticancer Agents Acting Directly and Selectively on Human Cancer Cell Mitochondria
Authors: Rotem Ronit , Heyfets Alina , Fingrut Orit , Blickstein Dorit , Shaklai Mati , Flescher Eliezer
Published: September 2005

We reported previously that jasmonates can kill human cancer cells. Many chemotherapeutic drugs induce mitochondrial membrane permeability transition, membrane depolarization, osmotic swelling, and release of cytochrome c, involving the opening of the permeability transition pore complex (PTPC). Because jasmonates exert their cytotoxic effects independent of transcription, translation, and p53 expression, we hypothesized that these compounds may act directly on mitochondria. Mitochondrial membrane depolarization was determined by flow cytometry, and cytochrome c release by Western blotting. Mitochondria were isolated by mechanical lysis and differential centrifugation. Cytotoxicity was measured by a tetrazolium-based assay, and mitochondrial swelling by spectrophotometry. Jasmonates induced membrane depolarization and cytochrome c release in intact human cancer cell lines. Jasmonates induced swelling in mitochondria isolated from Hep 3B hepatoma cells, but not in mitochondria isolated from 3T3 nontransformed cells or from normal lymphocytes, in a PTPC-mediated manner. Methyl jasmonate induced the release of cytochrome c from mitochondria isolated from cancer cell lines in a PTPC-mediated manner, but not from mitochondria isolated from normal lymphocytes. A correlation was found between cytotoxicity of methyl jasmonate and the percentage of leukemic cells in the blood of patients with chronic lymphocytic leukemia (CLL). Jasmonates induced membrane depolarization in CLL cells, and swelling and release of cytochrome c in mitochondria isolated from these cells. In conclusion, jasmonates act directly on mitochondria derived from cancer cells in a PTPC-mediated manner, and could therefore bypass premitochondrial apoptotic blocks. Jasmonates are promising candidates for the treatment of CLL and other types of cancer.
CD4+CD25+ Regulatory Lymphocytes Induce Regression of Intestinal Tumors in ApcMin/+ Mice
Authors: Erdman Susan E. , Sohn Jane J. , Rao Varada P. , Nambiar Prashant R. , Ge Zhongming , Fox James G. , Schauer David B.
Published: September 2005

Colorectal cancer in humans results from sequential genetic changes in intestinal epithelia commencing with inactivation of the APC tumor suppressor gene. Roles for host immunity in epithelial tumorigenesis are poorly understood. It has been previously shown that CD4+CD25+ lymphocytes inhibit colitis-associated epithelial tumors in Rag-deficient mice. Here we show that addition of CD4+CD25+ lymphocytes in ApcMin/+ mice reduces multiplicity of epithelial adenomas. Interleukin-10 was required in regulatory cells for therapeutic effect. Recipients of regulatory cells showed increased apoptosis and down-regulation of cyclooxygenase-2 within tumors coincident with tumor regression. These data suggest a role for regulatory lymphocytes in epithelial homeostasis in the ApcMin/+ mouse model of intestinal polyposis. Similarities with cancer of the breast, prostate, lung, and other sites raise the possibility of broader roles for regulatory lymphocytes in prevention and treatment of epithelial cancers in humans.
Broad-Spectrum G Protein–Coupled Receptor Antagonist, [D-Arg1,D-Trp5,7,9,Leu11]SP: A Dual Inhibitor of Growth and Angiogenesis in Pancreatic Cancer
Authors: Guha Sushovan , Eibl Guido , Kisfalvi Krisztina , Fan Robert S. , Burdick Marie , Reber Howard , Hines Oscar J. , Strieter Robert , Rozengurt Enrique
Published: September 2005

Substance P analogues, including [D-Arg1,D-Trp5,7,9,Leu11]SP (SPA) are broad-spectrum G protein–coupled receptor (GPCR) antagonists that have potential antitumorigenic activities, although the mechanism(s) are not completely understood. Here, we examined the effects of SPA in ductal pancreatic cancers that express multiple GPCRs for mitogenic agonists and also produce proangiogenic chemokines. Using HPAF-II, a well-differentiated pancreatic cancer cell line as our model system, we showed that SPA inhibited multiple neuropeptide-induced Ca2+ mobilization, DNA synthesis, and anchorage-independent growth in vitro. SPA also significantly attenuated the growth of HPAF-II tumor xenografts in nude mice beyond the treatment period. Interestingly, SPA markedly increased apoptosis but moderately decreased proliferation marker, Ki-67 in the tumor xenografts implying additional mechanism(s) for the significant growth inhibitory effect observed in vivo. HPAF-II cells express ELR+ CXC chemokines, including IL-8/CXCL8, which bind to CXCR2 (a member of GPCR superfamily) and promote angiogenesis in multiple cancers, including pancreatic cancer. SPA inhibited CXCR2-mediated Ca2+ mobilization and blocked specifically IL-8/CXCL8-induced angiogenesis in rat corneal micropocket assay in vivo. A salient feature of the results presented here is that SPA markedly reduced tumor-associated angiogenesis in the HPAF-II xenografts in vivo. Our results show that SPA, a broad-spectrum GPCR antagonist attenuates tumor growth in pancreatic cancer via a dual mechanism involving both the antiproliferative and antiangiogenic properties. We conclude that this novel dual-inhibitory property of SPA could be of significant therapeutic value in pancreatic cancer, when used in combination with other antiproliferative and/or antiangiogenic agents.