bluuebunny/crossref_metadata_2025_split huggingface dataset:
Deletion of STAT5 prevents HER2/Neu/ErbB2-induced mammary tumor development.
Authors: Yamaji D , Robinson GW , Muller WJ , Hennighausen L 
Published: December 2010

Abstract
Abstract #3045
HER2 (ErbB2/Neu in rodents) is overexpressed in a number of breast cancers and it activates several intracellular signaling pathways by recruiting adaptor proteins. Among them, Shc or Gab2 signaling mediates ErbB2/Neu-induced mammary tumor progression. HER2 activates the transcription factors STAT5A/B but their contribution to the etiology of breast cancer remains to be elucidated. STAT5 mediates signals from a wide variety of cytokine receptors, including the EGFR and ErbB4. Further, constitutive activation of STAT5 has been observed in human breast cancer, leukemia and many solid tumors. To address whether STAT5 mediates HER2/ErbB2/Neu-induced breast cancer progression, both Stat5 genes were deleted specifically in ErbB2/Neu oncogene (known as HER2 in human)-expressing mammary epithelial cells in mice. Briefly, transgenic mice carrying floxed Stat5 alleles (Stat5fl/fl mice) were mated with transgenic MMTV/NIC mice expressing both activated Neu/ErbB2 and Cre recombinase from the same bicistronic transcript due to the presence of an internal ribosome entry site (IRES) between the two cDNA sequences (NIC) under the control of mouse mammary tumor virus (MMTV) long terminal repeat. Whole mount staining of mammary tissue of MMTV/NIC mice demonstrated that mammary glands of control virgin NIC mice (MMTV/NIC;Stat5+/+) exhibited hyperplastic lesions at 5 months of age, while no lesions were detected in NIC mice that lacked STAT5 (MMTV/NIC;Stat5fl/fl). Histological analysis revealed the absence of hyperplastic or neoplastic lesions in MMTV/NIC;Stat5fl/fl mammary glands. These results indicate that inactivation of Stat5 results in the absence of hyperplasias in spite of overexpression of ErbB2/Neu in mammary epithelium and suggest that activation of STAT5 contributes to the development of HER2-induced breast cancer.
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3045.
A multi-marker QPCR panel for the detection of circulating tumor cells predicts survival in breast cancer patients.
Authors: Molloy TJ , Bosma AJ , Baumbusch LO , Borgen E , van't Veer LJ , Naume B 
Published: December 2010

Abstract
Abstract #305
The detection of circulating tumor cells (CTCs) in the blood of cancer patients is a promising tool for risk stratification, treatment tailoring, and monitoring of the disease state. We previously developed a QPCR-based detection platform for the semi-quantitation of circulating tumor cells in the peripheral blood of breast cancer patients. This CTC assay combines gene expression data from 4 tumor marker genes into a single score using a quadratic discriminant analysis, and is optimized such that positivity indicates tumor cell presence, and negativity indicates tumor cell absence. An initial cohort of metastatic patients demonstrated that score positivity was correlated to a significantly shorter time to disease progression.&#x2028; The current study aimed to validate these results by using the CTC assay in an independent, retrospective patient series consisting of 111 non-metastatic stage I-III breast cancer patients (median followup 7.3 years), 16 metastatic breast cancer patients, and 28 healthy controls. Assay score positivity was observed in 14 out of 16 (88%) metastatic patients, 16 out of 111 (14%) non-metastatic stage I-III patients, and 0 out of 28 (0%) healthy female controls.&#x2028; In the early stage patient group, a positive CTC score was correlated to significantly poorer relapse-free survival (HR = 3.6, 95% CI = 1.7-7.9, p &lt; 0.01) and overall survival (HR = 3.2, 95% CI = 1.6-6.1, p &lt; 0.01). The assay was particularly powerful in patients with no lymph node metastases at time of diagnosis (relapse-free survival HR = 13.0, 95%CI = 3.0-55.7, p &lt; 0.01, overall survival HR = 6.3, 95% CI = 1.9-21.1, p &lt; 0.01). This platform compared very favorably to the traditional immunohistochemistry-based assay for disseminated tumor cell detection in bone marrow utilizing pan-anticytokeratin staining (AE1/AE3), which was not a significant predictor of survival in this patient group (HR = 1.3, 95% CI = 0.6-2.4, p = 0.49). In multivariate analyses, our CTC assay was a significant, independent predictor of overall survival.&#x2028; Work is currently ongoing to expand the study to include an additional 500-600 patients which should serve as a robust validation of the assay. This CTC detection platform represents an objective assay with both high specificity and prognostic power, and could be an effective clinical tool for outcome prediction in breast cancer patients.&#x2028; This work was supported by the Sixth Framework Program of the European Commission as part of the international DISMAL collaboration for research into disseminated epithelial malignancies.
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 305.
The antitumorgenic actions of estrogen receptor beta in breast cancer cells.
Authors: Wimalasena J , Baek S , Sukhthankar M , Strom A 
Published: December 2010

Abstract
Abstract #3056
Recent studies have suggested that ERβ may oppose actions of ERα in breast cancer cells and clinical studies indicate that loss of ERβ expression in ERα positive tumors is associated with a poor prognosis and perhaps resistance to tamoxifen therapy. Clinical evidence indicates that in post menopausal women hormone replacement therapy significantly decreased incidence of colon cancer, suggesting that estrogens have a protective role . We have recently found that in SW 480 colon cancer cells, (ER negative) stable expression of ERβ decreased SKP2, c-myc but not p27kip1 mRNA measured by real time PCR. These results were confirmed for c-myc and SKP2 at the protein level. However, ERβ expression increased only p27 protein levels. Addition of E2 did not regulate effects of ERβ expression.&#x2028; Similar results have been observed with T47D (ER positive breast cancer cells) stably over expressing ERβ. In the latter cells and MCF7 (ER alpha positive) cells over expressing ERβ, E2 induced β catenin protein expression was blocked by ERβ. The latter also blocked AKT and ERK activation by E2 and induced apoptosis, in an E2 independent fashion. ERβ expression also blocked E2 induced growth in MCF 7 cells. Antibody array analysis showed that ERβ regulated &gt;100 proteins at or above the 2 fold level in T47D breast cancer cells,where as 2D PAGE/MS showed that over 60 proteins changed significantly, both types of analysis and Western blots indicate that ERβ regulates Sp1,HSP70,β catenin, c-Jun, JNK,c-Jun ,BAD among other proteins. Antibody arrays and MS have therefore revealed unsuspected targets of ERβ action. Thus, ERβ appears to oppose several actions of ERα in breast cancer cells and block colon cancer cell growth, independently of E2. Design of selective ERβ activating agents or delivery of ERβ using gene therapy may be of substantial utility in the treatment of breast and colon cancer. Category27.
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3056.
No clinical relevance of standardized immunocytological and molecular methods for detection of disseminated tumor cells in bone marrow of patients with primary breast cancer.
Authors: Kaul S , Sonnauer M , Bartik B , Deckert A , Zeifang F , Bastert G , Fersis N 
Published: December 2010

Abstract
Abstract #306
Background: Bone marrow samples from 2093 patients operated for primary breast cancer (stage T1-4, N0/N+, M0/M1) at the University Hospital Heidelberg between 1999 und 2007 were analysed for disseminated tumor cells (DTC) by standard cytology on cytospin slides. In parallel a subgroup of 250 samples was analysed by immunobead-RT-PCR methods for CK19 expression.&#x2028; Material and Methods: Mononuclear cells were enriched by Ficoll density-gradient centrifugation. Cytospin-slides (mean 6) with 1x106 BM-cells were fixed in 3.5% buffered formalin at RT and endogenous AP and Ig were blocked with 10% acetic acid and 2.28% NaJO4. DTC were identified by CK antibodies 5D3 and A45-B/B3 (automated immunostainers, AP-techniques). Slides were analysed by automated picture analysis with the ACIS I and II systems (ChromaVision). Criteria for classification of disseminated tumor cells were in compliance with the publication of Fehm et al. (Cancer, Vol.107, 2006). 1x107 BM cells were used for immunomagnetic enrichment of epithelial cell types using antibodies targeting the cell membrane glycoproteins MUC1 and EpCAM. The markers cytokeratin 19 (CK19) and MG1 were analysed by real-time qRT-PCR using primers and FAM-labeled TaqMan probes of the UniversalProbeLibrary system (Roche AG, Basel, CH). The newly developed embedded tumor cell calibrator (ETC) technique was introduced for cell quantification.&#x2028; Results: Small cells characterized by an excentrically located small and clear nucleus were detected in 56% of the bone marrow samples. These cytokeratin-positive cells were identified as bone marrow stroma stem cells. Identical cell types were present in 27 samples from normal BM-donors. In contrast, tumor cells were characterized by strong and irregular cytoplasmic cytokeratin staining, a granular nucleus and a clearly enlarged nuclear size. These DTC had a mean value for the parameter area of 309 (n=13) according to the ACIS picture analysis. Using published tumor classification critera 40 (1.9%) from 2093 patients with primary breast carcinoma were scored DTC positive. At the basis of 2x106 BM-cells the molecular detection methods of a) endpoint RT-PCR for CK19 and b) real-time RT-PCR for CK19 and MG1 had positivity rates of 3.5% and 3.8%, respectively.&#x2028; Discussion: We have shown that bone marrow stroma cells are positive for various epithelial antigens including CK. Elimination of these cells either by size exclusion in picture analysis or by immunomagnetic separation results in tumor cell detection rates of less than 4% in 2x106 bone marrow cells. We conclude that cytological DTC analysis and the technique of immunomagnetic enrichment followed by molecular CK19 detection have no clinical relevance in patients with primary breast cancer.
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 306.
Breast tumor cells with PI3K mutation or HER2 amplification are selectively addicted to Akt signaling.
Authors: She Q , Chandarlapaty S , Ye Q , Lobo J , Haskell KM , Leander KR , DeFeo-Jones D , Huber HE , Rosen N 
Published: December 2010

Abstract
Abstract #3061
Background: Activation of the PI3K/Akt pathway is a common event in human cancers and is responsible for key aspects of the transformed phenotype. This pathway is activated in most breast cancers, but by different mechanisms including HER2 amplification, PI3K mutation and PTEN inactivation. Inhibition of this pathway is thus thought to be clinically useful, but the functional output of PI3K/Akt signaling and the corresponding clinical effects of its inhibition may be due to the mechanisms by which it is activated. The objective of this study was to determine the role of Akt activation in breast cancer as a function of mechanism of activation and whether inhibition of Akt signaling is a feasible approach to therapy.&#x2028; Methodology/Principal Findings: Using a panel of human breast cancer cell lines that harbor HER2 amplification, PI3K or PTEN mutations, or wild-type of PI3K and PTEN, and a selective, PH-domain dependent, allosteric inhibitor of Akt1 and Akt2 (AKTi-1/2), and a variety of biochemical, molecular, and cellular techniques as well as in vivo xenograft models, we show that AKTi-1/2 resulted in the selective inhibition of breast tumor cell lines with either mutant PI3K or amplified HER2, but not those in which PI3K/Akt signaling is not mutationally activated. Cellular sensitivity was due to induction of G1 arrest and of apoptosis and associated with inhibition of Akt signaling, loss of D-cyclin expression, and dephosphorylation of Rb. Most importantly, AKTi-1/2 effectively inhibited Akt kinase and its downstream effectors in vivo and caused complete suppression of the growth of breast cancer xenografts with PI3K mutation or HER2 amplification, including models of the latter selected for resistance to Herceptin. Furthermore, chronic administration of the drug was well-tolerated, causing only transient hyperglycemia without gross toxicity to the host despite the pleiotropic normal functions of Akt.&#x2028; Conclusions/Significance: Our data demonstrate the exquisite dependence of PI3K-mutated or HER2-amplified breast cancer cells on Akt signaling, and that effective inhibition of Akt in tumors is feasible and effective in vivo. These findings suggest that direct inhibition of Akt may represent a therapeutic strategy for breast cancers that are addicted to the pathway and in patients with clinical resistance to Herceptin.
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3061.
Orally active gnRH-antagonist AEZS-115 inhibits growth of human ovarian and breast cancers in vitro.
Authors: Engel JB , Ivanisevic M , Guenther E , Dietl J , Kaemmerer U , Hoenig A 
Published: December 2010

Abstract
Abstract #3065
Introduction: AEZS-115 is an orally active peptidomimetic antagonist of GnRH, which has been shown to block the pituitary GnRH receptor in nanomolar range. Recently an increasing number of human cancers have been demonstrated to express receptors for GnRH, which mediate growth promoting signals. Accordingly, we tested the antitumor activity of AEZS-115 in in vitro models of human breast and ovarian cancer.&#x2028; Material and Methods: Human ovarian SKOV3, Ovcar 3 as well breast cancer cell line MDA-MB 468 were analyzed for GnRH receptor expression by immunocytochemistry. To screen for a putative anti-tumor effect, these cell lines were incubated with increasing concentrations of AEZS-115, peptidic GnRH-antagonist Cetrorelix and GnRH-agonist Triptorelin (1, 10, 100 µm) for 48 hours and the number of viable cells was determined by crystal violet staining as well as by ATP-dependent luminometric assay.&#x2028; Results: Cell lines SKOV3, OVCAR3 and MDA-MB 468 expressed GnRH I receptors as demonstrated by immunehistochemistry. Both GnRH-antagonists dose dependently inhibited growth of all three cell lines, while GnRH-agonist Triptorelin showed marginal growth inhibition. At 10 µM AEZS-115 inhibited cell growth by 40-60%, at 100 µM growth inhibition was 60-80%. Inhibition with Cetrorelix at 100 µM ranged from 20-40%, while only minor effects on cell growth were seen at 10 µM. These results obtained by crystal violet staining were confirmed by additional luminometric evaluation of the ATP content after treatment with the respective substances.&#x2028; Conclusions: To our knowledge here we report for the first time in vitro anti-cancer activity for a peptidomimetic GnRH antagonist.&#x2028; AEZS-115 showed substantial anti-tumor activity in human ovarian and breast cancer cell lines, while GnRH-agonist Triptorelin showed only minor growth inhibition. Surprisingly AEZS-115 was somewhat more potent than peptidic GnRH-antagonist Cetrorelix. Due to the good antitumor-activity and the possible oral administration AEZS-115 should be a promising candidate for in vivo studies.
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3065.
Molecular mechanisms for leptin regulation of VEGF in breast cancer cells.
Authors: Xu Y , Watters A , Leibovich SJ , Mann D , Rueda BR , Gonzalez RR 
Published: December 2010

Abstract
Abstract #3071
Background: We have previously reported that in vitro and in vivo leptin signaling mediates proliferation of mouse 4T1 mammary tumor (MT) cells and levels of VEGF and VEGFR2. Therefore, we hypothesize that leptin can contribute to MT growth by augmenting angiogenesis through the regulation of VEGF expression. To test this we assessed whether leptin regulates VEGF promoter activity in mouse MT cells and if leptin-induced factors (HIF-1α, NFκB, AP1, SP1) regulate the VEGF promoter. Materials and Methods: Mouse MT cells (4T1, EM6 and MMT) were transiently transfected with molecular engineered luciferase-reporters (pGL3) for mouse VEGF promoter (full-length) and transcription factor-binding deletions for hypoxia responsive element (HRE), AP1, SP1 and NFκB. Leptin dose-response effects on reporter activity and VEGF levels (protein and mRNA) were investigated using ELISA, Western blot and real-time PCR, respectively. To further assess leptin regulation of VEGF expression in MT cells the effects of hypoxia (CoCl2, hypoxia mimetic agent) alone and combined with leptin on VEGF promoter activity were investigated. To assess which leptin-induced signaling pathways/transcription factors are linked to VEGF regulation in MT cells inhibitors for: (1) JAK2/STAT3, MEK-1/MAPK and PI-3K/Akt-1 pathways and; (2) target molecules NFκB; SP1; AP1 and HIF-1α were used. The effects of leptin/CoCl2 and inhibitors on luciferase activity of transfected cells were compared using pRL-TK renilla luciferase as control and the Dual-Luciferase Reporter Assay System. Results: Our data suggest that leptin signaling can regulate the transcriptional activity of VEGF gene in breast cancer cells by activating gene transcription at several sites of the VEGF promoter. Leptin-induced HIF-1α has a relevant role in the regulation of VEGF expression in MT cells. Leptin can also increase VEGF-levels (protein and mRNA) through the specific activation of AP1, SP1, and NFκB. PI-3K activity was mainly linked to leptin regulatory effects on VEGF. However, diverse mechanisms for leptin regulation of VEGF expression were found in the different MT cells. Discussion: Our results provide novel information on the molecular mechanisms for leptin-induced angiogenic effects in breast cancer. Our data further suggest that disruption of leptin signaling could impact angiogenesis and MT growth by inhibiting VEGF expression. Thus targeted disruption of leptin-signaling could serve as method of prevention/treatment of breast cancer. This work was supported in part by the Susan G. Komen Foundation for the Cure (to R.R.G.; BC 504370); UAB Breast SPORE Award (to R.R.G) and Contraceptive Research and Development Program (CONRAD; CIG-07-114 to R.R.G).
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3071.
Rapamycin-regulated gene expression signature determines prognosis in breast cancer.
Authors: Akcakanat A , Zhang L , Tsavachidis S , Meric-Bernstam F 
Published: December 2010

Abstract
Abstract #3072
Background: Mammalian target of rapamycin (mTOR) is a serine/threonine kinase involved in multiple intracellular signaling pathways promoting tumor growth. mTOR is aberrantly activated in a significant portion of breast cancers and is a promising target for treatment. Rapamycin and its analogues are in clinical trials for breast cancer treatment. Patterns of gene expression (metagenes) may also be used to simulate a biologic process or effects of a drug treatment. In this study, we tested the hypothesis that the gene-expression signature regulated by rapamycin could predict disease outcome for patients with breast cancer.&#x2028; Methods: MDA-MB-468 breast cancer cell line is triple negative and PTEN null. Sensitivity of MDA-MB-468 breast cancer cell line to rapamycin was determined by in vitro growth assays and in vivo tumor studies. Total RNA was extracted from cell lines treated with rapamycin or DMSO for 24 hours and xenografts treated with DMSO or rapamycin for 1 or 22 days. Total RNA was used for expression profiling and hybridized to Affymetrix HG-U133 Plus 2.0 arrays. We used two well-described primary breast cancer datasets of 251 (Miller et al, Proc. Natl. Acad. Sci. USA 2005;102:13550) and 286 (Wang et al, Lancet. 2005;365:671) patients from the public domain and assessed the prognostic capability of rapamycin-regulated gene expression signatures.&#x2028; Results: Colony formation and sulforhodazine B (IC50 &lt; 1 nM) assays, and xenograft animals showed that MDA-MB-468 cells were sensitive to treatment with rapamycin. The comparison of in vitro and in vivo gene expression data identified a 31-gene expression signature that was up- regulated by rapamycin treatment in vitro as well as in vivo (FDR of 0.1). From the 31 genes on HG-U133 Plus 2.0 array, 20 that were included on HG-U133A array were used for analysis. In the Miller dataset, rapamycin metagene index (RMI) did not correlate with tumor size or lymph node status. High (0.75 percentile) RMI was significantly associated with longer survival (P=0.015). On multivariate analysis, RMI (P=0.029), tumor size (P=0.015) and lymph node status (P=0.001) were prognostic. In the Wang dataset, RMI predicted time to disease relapse (P=0.009).&#x2028; Conclusion: Rapamycin-regulated gene expression signature predicts clinical outcome in breast cancer. This supports the central role of mTOR signaling in breast cancer biology and provides further impetus to pursue mTOR-targeted therapies for breast cancer treatment.
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3072.
Cyr61 (CCN1) is a novel target for Zometa (zoledronic acid) in breast cancer bone metastasis.
Authors: Espinoza I , Liu H , Dimri M , Lupu R 
Published: December 2010

Abstract
Abstract #3074
Background: Cyr61, currently known as CCN1, is a pro-angiogenic factor highly expressed in triple negative breast carcinomas. CCN1 binds, among others, to αvβ3 integrin receptor, which is concomitantly expressed with CCN1 in triple negative carcinomas. It has clinically established that a greater part of the tumor initially diagnose as triple negative eventually metastasize to the bone. Women with advanced breast cancer often develop bone metastases. Currently, many patients receive bisphosphonate treatment as a support treatment to maintain bone density. Zometa (Zoledronic acid=ZOL), a third generation amino-bisphosphonate, inhibits bone resorption and it might prevent development of new osteolytic lesions; lesions induced by tumor metastases. Provided that: 1) ZOL has a direct anti-tumor activity on breast cancer cells in vitro, 2) CCN1:αvβ3 is an autocrine loop shown to be involved in breast cancer cells which metastasize to the bone, 3) ZOL inhibits αvβ3 expression in the cell surface of endothelial cells, and CCN1 induces the expression of αvβ3 expression.&#x2028; Material and Methods: Using MTT assay we analyzed the effect of ZOL in the viability of cells overexpressing CCN1:αvβ3. The study whether the effect of ZOL was at the transcriptional level of CCN1 a Luciferase reporter assay was performed. To study whether FOXO3a binding site on CCN1 promoter was an important site for ZOL effect on CCN1 we used a CCN1-promoter containing a deletion in the FOXO3a binding site and we performed the Luciferase reporter assay. We also analyze the effect of ZOL in the anchorage-independent growth by soft agar assay and in the branching and morphogenesis in 3D Matrigel culture.&#x2028; Results: We found that: a) ZOL regulates the expression of CCN1 expression in triple negative breast cancer cell lines; b) the IC50 for Zometa for CCN1:αvβ3 expressing cells is lower (about 12μM) than the IC50 for cells that express low to undetectable levels of CCN1:αvβ3 cells; c) ZOL specifically inhibited CCN1 at a protein and transcription expression levels in a concentration-dependent manner; d) FOXO3a is the site by which ZOL induces transcriptional activation of CCN1; e) ZOL induced specific inhibition of anchorage independent growth of CCN1:αvβ3 cells in a dose dependent manner, and f) ZOL induces Mesenchimal-Epithelial Transition (MET) of CCN1:αvβ3 expressing cells and inhibited the generation of branching and morphogenesis in 3D in Matrigel culture of CCN1:αvβ3 expressing cells.&#x2028; Discusion: Collectively, these data demonstrated for first time a specific effect of ZOL on a pro-angiogenic factor involved in triple negative carcinomas; providing a new model for the development of a therapeutic strategy for ZOL.
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3074.