Breast cancer research: BCR (Breast Canc Res)

Publications in this journal

• Article: High mammographic density in women of Ashkenazi Jewish descent.

  Jennifer L Caswell, Karla Kerlikowske, John A Shepherd, Steven R Cummings, Donglei Hu, Scott Huntsman, Elad Ziv
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  ABSTRACT: INTRODUCTION: Percent mammographic density (PMD) adjusted for age and BMI is one of the strongest risk factors for breast cancer and is known to be approximately 60 percent heritable. Here we report a finding of an association between genetic ancestry and adjusted PMD. METHODS: We selected self-identified Caucasian women in the California Pacific Medical Center Research Institute Cohort whose screening mammograms placed them in the top or bottom quintiles of age- and body mass index-adjusted PMD. Our final data set included 474 women with the highest adjusted PMD and 469 with the lowest genotyped on the Illumina 1M platform. Principal component analysis (PCA) and identity-by-descent (IBD) analyses allowed us to infer the women's genetic ancestry and correlate it with adjusted PMD. RESULTS: Women of Ashkenazi Jewish ancestry, as defined by the first principal component (PC1) of PCA and identity-by-descent analyses, represented approximately 15 percent of the sample. Ashkenazi Jewish ancestry, defined by PC1, was associated with higher adjusted PMD (p = 0.004). Using multivariate regression to adjust for epidemiologic factors associated with PMD, including age at parity and use of postmenopausal hormone therapy, did not attenuate the association. CONCLUSION: Women of Ashkenazi Jewish ancestry based on genetic analysis are more likely to have high age- and BMI-adjusted PMD. Ashkenazi Jews may have a unique set of genetic variants or environmental risk factors that increase mammographic density.
  Breast cancer research: BCR 05/2013; 15(3):R40.
• Article: The expression and significance of insulin-like growth factor-1 receptor and its pathway on breast cancer stem/progenitors.

  Wen-Wei Chang, Ruey-Jen Lin, John Yu, Wen-Ying Chang, Chiung-Hui Fu, Alan Chuan-Ying Lai, Jyh-Cherng Yu, Alice L Yu
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  ABSTRACT: INTRODUCTION: Dysregulation of the insulin-like growth factor-1 receptor (IGF-1R)/ PI3K/Akt pathway was shown to correlate with breast cancer disease progression. Cancer stem cells (CSCs) are a subpopulation within cancer cells which participate in tumor initiation, radio/chemoresistance and metastasis. In breast cancer, breast CSCs (BCSCs) were identified as CD24-CD44+ cells or cells with high intracellular aldehyde dehydrogenase activity (ALDH+). Elucidation of the role of IGF-1R in breast cancer stem cells (BCSCs) is crucial to the design of breast cancer therapies targeting BCSCs. METHODS: IGF-1R expression in BCSCs and non-CSCs sorted from xenografts of human primary breast cancers was examined by FACS, western blot analysis and immunoprecipitation (IP). The role of IGF-1R in BCSCs was assessed by IGF-1R blockade with chemical inhibitor and gene silencing. The involvement of PI3K/Akt/mTOR as downstream pathway was studied by their phosphorylation status upon IGF-1R inhibition and the effects of chemical inhibitors of these signaling molecules on BCSCs. We also studied 16 clinical specimens of breast cancer for the expression of phosphor-Akt in the BCSCs by FACS. RESULTS: Expression of phosphorylated IGF-1R was greater in BCSCs than in non-BCSCs from xenografts of human breast cancer which were supported by western blot and IP experiments. The sorted IGF-1R expressing cells displayed features of cancer stem/progenitors such as mammosphere formation in vitro and tumorigenicity in vivo, both of which were suppressed by knockdown of IGF-1R. A specific inhibitor of the IGF-1R, PPP, suppressed the phospho-AktSer473 and preferentially decreased ALDH+ BCSC populations of human breast cancer cells. Furthermore, PPP inhibited the capacity of CD24-CD44+ BCSCs to undergo epithelial-mesenchymal transition process with downregulation of mesenchymal markers. Inhibitors of signal molecules downstream of IGR-1R including PI3K/Akt/mTOR also reduced the ALDH + population of breast cancer cells. Furthermore, the mTOR inhibitor, rapamycin, suppressed BCSCs in vitro and in vivo. CONCLUSIONS: Our data support the notion that IGF-1R is a marker of stemness, and IGF-1R and its downstream PI3K/Akt/mTOR pathway are attractive targets for therapy directed against breast cancer stem/progenitors.
  Breast cancer research: BCR 05/2013; 15(3):R39.
• Article: Molecular apocrine breast cancers are aggressive estrogen receptor negative tumors overexpressing either HER2 or GCDFP15.

  Jacqueline Lehmann-Che, Anne Sophie Hamy, Raphael Porcher, Marc Barritault, Fatiha Bouhidel, Hanadi Habuellelah, Solenne Leman-Detours, Anne de Roquancourt, Laurence Cahen-Doidy, Edwige Bourstyn, Patricia de Cremoux, Cedric de Bazelaire, Marcela Albiter, Sylvie Giacchetti, Caroline Cuvier, Anne Janin, Marc Espie, Hugues de The, Philippe Bertheau
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  ABSTRACT: INTRODUCTION: Molecular apocrine (MA) tumors are estrogen receptor (ER) negative breast cancers characterized by androgen receptor (AR) expression. We analysed a group of 58 transcriptionally defined MA tumors and proposed a new tool to identify these tumors. METHODS: We performed quantitative reverse transcription PCR (qRT-PCR) for ER, AR, FOXA1 and AR-related genes, and immunohistochemistry (IHC) for ER, PR, HER2, CK5/6, CK17, EGFR, Ki67, AR, FOXA1 and GCDFP15 and we analysed clinical features. RESULTS: MA tumors were all characterized by ER(-) AR(+) FOXA1(+) and AR-related genes positive mRNA profile. IHC staining on these tumors showed 93% ER(-), only 58% AR(+) and 90% FOXA1(+). 67% and 57% MA tumors were HER2(3+) and GCDFP15(+), respectively. Almost all MA tumors (94%) had the IHC signature "HER2(3+) or GCDFP15(+)" but none of 13 control basal-like (BL) tumors did. Clinically, MA tumors were rather aggressive, with poor prognostic factors. CONCLUSION: MA tumors could be better defined by their qRT-PCR-AR profile than by AR IHC. In addition, we found that "HER2 or GCDFP15" protein overexpression is a sensitive and specific tool to differentiate MA from BL in the context of ER negative tumors. A composite molecular and IHC signature could therefore help to identify MA tumors in the daily practice.
  Breast cancer research: BCR 05/2013; 15(3):R37.
• Article: Progesterone metabolites regulate induction, growth and suppression of estrogen- and progesterone receptor-negative human breast cell tumors.

  John P Wiebe, Guihua Zhang, Ian Welch, Heather-Anne T Cadieux-Pitre
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  ABSTRACT: INTRODUCTION: Of the nearly 1.4 million new cases of breast cancer diagnosed each year, a large proportion is characterized as hormone receptor negative, lacking estrogen receptors (ER) and/or progesterone receptors (PR). Patients with receptor-negative tumors do not respond to current steroid hormone based therapies and generally have significantly higher risk of recurrence and mortality compared to patients with tumors that are ER- and/or PR-positive. Previous in vitro studies had shown that the progesterone metabolites, 5-dihydroprogesterone (5P) and 3-dihydroprogesterone (3HP), respectively, exhibit pro-cancer and anti-cancer effects on receptor-negative human breast cell lines. Here in vivo studies were conducted to investigate the ability of 5P and 3HP to control initiation, growth and regression of ER/PR-negative human breast cell tumors. METHODS: ER/PR-negative human breast cells (MDA-MB-231) were implanted into mammary fat pads of immunosuppressed mice and the effects of 5P and 3HP treatments on tumor initiation, growth, suppression/regression and histopathology were assessed in five separate experiments. Specific radioimmunoassays and gas chromatography-mass spectrometry were used to measure 5P, 3HP and progesterone in mouse serum and tumors. RESULTS: Onset and growth of ER/PR-negative human breast cell tumors were significantly stimulated by 5P and inhibited by 3HP. When both hormones were applied simultaneously, the stimulatory effects of 5P were abrogated by the inhibitory effects of 3HP and vice versa. Treatment with 3HP subsequent to 5P-induced tumor initiation resulted in suppression of further tumorigenesis and regression of existing tumors. The levels of 5P in tumors, regardless of treatment, were about 10-fold higher than the levels of 3HP and the 5P:3HP ratios were about 5-fold higher than in serum, indicating significant changes in endogenous synthesis of these hormones in tumorous breast tissues. CONCLUSIONS: The studies showed that estrogen/progesterone insensitive breast tumors are sensitive to, and controlled by, the progesterone metabolites 5P and 3HP. Tumorigenesis of ER/PR-negative breast cells is significantly enhanced by 5P and suppressed by 3HP, the outcome depending upon the relative concentrations of these two hormones in the microenvironment in the breast regions. The findings show that the production of 5P greatly exceeds that of 3HP in ER/PR-negative tumors and that treatment with 3HP can effectively block tumorigenesis and regress existing tumors. The results provide the first hormonal theory to explain tumorigenesis of ER/PR-negative breast tissues and support the hypothesis that a high 3HP-to-5P concentration ratio in the microenvironment may foster normalcy in non-cancerous breast regions. The findings suggest new diagnostics based on the relative levels of these hormones and new approaches to prevention and treatment of breast cancers based on regulating the levels and action mechanisms of anti- and pro-cancer progesterone metabolites.
  Breast cancer research: BCR 05/2013; 15(3):R38.
• Article: Pregnancy protection of breast cancer: new insights reveal unanswered questions.

  Daniel Medina
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  ABSTRACT: The recent paper by Meier-Abt and colleagues on pregnancy protection of breast cancer development takes a different approach to the problem and focused on the effect of parity on the cell subpopulations of the mouse mammary gland. Their results demonstrate that parity decreases the cell number of the hormone receptor-positive luminal cells (that is, luminal Sca1+) but not the basal stem/progenitor cells (CD24lo/CD49hi). Additionally, microarray studies demonstrate that wnt4 expression from the luminal Sca1+ cells is markedly reduced as is the wnt signaling pathway in basal cells. One important implication from these results is that targeting the wnt signaling pathway might be a feasible prevention approach in humans.
  Breast cancer research: BCR 05/2013; 15(3):103.
• Article: Parity induces differentiation and reduces Wnt/Notch signaling ratio and proliferation potential of basal stem/progenitor cells isolated from mouse mammary epithelium.

  Fabienne Meier-Abt, Emanuela Milani, Tim Roloff, Heike Brinkhaus, Stephan Duss, Dominique S Meyer, Ina Klebba, Piotr J Balwierz, Erik van Nimwegen, Mohamed Bentires-Alj
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  ABSTRACT: INTRODUCTION: Early pregnancy has a strong protective effect against breast cancer in humans and rodents, but the underlying mechanism is unknown. Because breast cancers are thought to arise from specific cell subpopulations of mammary epithelia, we studied the effect of parity on the transcriptome and the differentiation/proliferation potential of specific luminal and basal mammary cells in mice. METHODS: Mammary epithelial cell subpopulations (luminal Sca1-, luminal Sca1+, basal stem/progenitor, and basal myoepithelial cells) were isolated by flow cytometry from parous and age-matched virgin mice and examined by using a combination of unbiased genomics, bioinformatics, in vitro colony formation, and in vivo limiting dilution transplantation assays. Specific findings were further investigated with immunohistochemistry in entire glands of parous and age-matched virgin mice. RESULTS: Transcriptome analysis revealed an upregulation of differentiation genes and a marked decrease in the Wnt/Notch signaling ratio in basal stem/progenitor cells of parous mice. Separate bioinformatics analyses showed reduced activity for the canonical Wnt transcription factor LEF1/TCF7 and increased activity for the Wnt repressor TCF3. This finding was specific for basal stem/progenitor cells and was associated with downregulation of potentially carcinogenic pathways and a reduction in the proliferation potential of this cell subpopulation in vitro and in vivo. As a possible mechanism for decreased Wnt signaling in basal stem/progenitor cells, we found a more than threefold reduction in the expression of the secreted Wnt ligand Wnt4 in total mammary cells from parous mice, which corresponded to a similar decrease in the proportion of Wnt4-secreting and estrogen/progesterone receptor-positive cells. Because recombinant Wnt4 rescued the proliferation defect of basal stem/progenitor cells in vitro, reduced Wnt4 secretion appears to be causally related to parity-induced alterations of basal stem/progenitor cell properties in mice. CONCLUSIONS: By revealing that parity induces differentiation and downregulates the Wnt/Notch signaling ratio and the in vitro and in vivo proliferation potential of basal stem/progenitor cells in mice, our study sheds light on the long-term consequences of an early pregnancy. Furthermore, it opens the door to future studies assessing whether inhibitors of the Wnt pathway may be used to mimic the parity-induced protective effect against breast cancer.
  Breast cancer research: BCR 04/2013; 15(2):R36.
• Article: Microwave imaging for neoadjuvant chemotherapy monitoring: initial clinical experience.

  Paul M Meaney, Peter A Kaufman, Lori S Muffly, Michael Click, Steven P Poplack, Wendy A Wells, Gary N Schwartz, Roberta M di Florio-Alexander, Tor D Tosteson, Zhongze Li, Shireen D Geimer, Margaret W Fanning, Tian Zhou, Neil R Epstein, Keith D Paulsen
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  ABSTRACT: INTRODUCTION: Microwave tomography recovers images of tissue dielectric properties, which appear to be specific for breast cancer, with low-cost technology that does not present an exposure risk, suggesting the modality may be a good candidate for monitoring neoadjuvant chemotherapy. METHODS: Eight patients undergoing neoadjuvant chemotherapy for locally advanced breast cancer were imaged longitudinally five to eight times during the course of treatment. At the start of therapy, regions of interest (ROIs) were identified from contrast-enhanced magnetic resonance imaging studies. During subsequent microwave examinations, subjects were positioned with their breasts pendant in a coupling fluid and surrounded by an immersed antenna array. Microwave property values were extracted from the ROIs through an automated procedure and statistical analyses were performed to assess short term (30 days) and longer term (four to six months) dielectric property changes. RESULTS: Two patient cases (one complete and one partial response) are presented in detail and demonstrate changes in microwave properties commensurate with the degree of treatment response observed pathologically. Normalized mean conductivity in ROIs from patients with complete pathological responses was significantly different from that of partial responders (P value = 0.004). In addition, the normalized conductivity measure also correlated well with complete pathological response at 30 days (P value = 0.002). CONCLUSIONS: These preliminary findings suggest that both early and late conductivity property changes correlate well with overall treatment response to neoadjuvant therapy in locally advanced breast cancer. This result is consistent with earlier clinical outcomes that lesion conductivity is specific to differentiating breast cancer from benign lesions and normal tissue.
  Breast cancer research: BCR 04/2013; 15(2):R35.
• Article: The estrogen-regulated anterior gradient 2 (AGR2) protein in breast cancer: a potential drug target and biomarker.

  Michael L Salmans, Fang Zhao, Bogi Andersen
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  ABSTRACT: Initially discovered as an estrogen-responsive gene in breast cancer cell lines, anterior gradient 2 (AGR2) is a developmentally regulated gene belonging to the protein disulfide isomerase (PDI) gene family. Developmentally, AGR2 is expressed in the mammary gland in an estrogen-dependent manner, and AGR2 knockout and overexpression mouse models indicate that the gene promotes lobuloalveolar development by stimulating cell proliferation. Although AGR2 overexpression alone seems insufficient for breast tumorigenesis in mice, several lines of investigations suggest that AGR2 promotes breast tumorigenesis. Overexpression of AGR2 in several breast cancer cell lines increases cell survival in clonogenic assays and cell proliferation, whereas AGR2 loss of function leads to decreased cell cycle progression and cell death. In addition, AGR2 was shown to promote metastasis of breast epithelial cells in an in vivo metastasis assay. As a PDI, AGR2 is thought to be involved in the unfolded protein response that alleviates endoplasmic reticulum stress. Since cancer has to overcome proteotoxic stress due to excess protein production, AGR2 may be one of many pro-survival factors recruited to assist in protein folding or degradation or both. When AGR2 is secreted, it plays a role in cellular adhesion and dissemination of metastatic tumor cells. In breast cancer, AGR2 expression is associated with estrogen receptor (ER)-positive tumors; its overexpression is a predictor of poor prognosis. The AGR2 gene is directly targeted by ER-alpha, which is preferentially bound in tumors with poor outcome. Whereas aromatase inhibitor therapy decreases AGR2 expression, tamoxifen acts as an agonist of AGR2 expression in ER-positive tumors, perhaps contributing to tamoxifen resistance. AGR2 is also overexpressed in a subset of ER-negative tumors. Furthermore, AGR2 expression is associated with the dissemination of metastatic breast cancer cells and can be used as a marker to identify circulating tumor cells and metastatic cells in sentinel lymph nodes. In conclusion, AGR2 is a promising drug target in breast cancer and may serve as a useful prognostic indicator as well as a marker of breast cancer metastasis.
  Breast cancer research: BCR 04/2013; 15(2):204.
• Article: Activating mutations and senescence secretome: new insights into HER2 activation, drug sensitivity and metastatic progression.

  Swarnali Acharyya
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  ABSTRACT: HER2 amplification and overexpression is observed in approximately 20% of breast cancers and is strongly associated with poor prognosis and therapeutic responsiveness to HER2 targeted agents. A recent study by Bose and colleagues suggests that another subset of breast cancer patients without HER2 amplification but with activating HER2 mutation might also benefit from existing HER2-targeted agents and the authors functionally characterize these somatic mutations in experimental models. In a second study on HER2-driven breast cancer, Angelini and colleagues investigate how the constitutively active, truncated carboxy-terminal fragment of HER2, p95HER2, promotes metastatic progression through non-cellautonomous secretion of factors from senescent cells. These new findings advance our understanding of HER2 biology in the context of HER2 activation as well as offer new insights into our understanding of drug sensitivity and metastatic progression.
  Breast cancer research: BCR 04/2013; 15(2):309.
• Article: Relationship of serum estrogens and estrogen metabolites to postmenopausal breast cancer risk: a nested case-control study.

  Roni T Falk, Louise A Brinton, Joanne F Dorgan, Barbara J Fuhrman, Timothy D Veenstra, Xia Xu, Gretchen L Gierach
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  ABSTRACT: INTRODUCTION: Elevated levels of circulating estrogens are linked to breast cancer risk among postmenopausal women but little is known about the importance of estrogen metabolism. A recently developed liquid chromatography tandem mass spectrometry-based method (LC-MS/MS) measuring a panel of 15 estrogen metabolites (EM) has been evaluated in one study, linking high levels of 2-pathway metabolites relative to the parent estrogens to reduced breast cancer risk. We analyzed this panel of EM in a nested case-control study of postmenopausal breast cancer. METHODS: Between 1977 and 1987, 6915 women provided blood samples to the Columbia Missouri Serum Bank and were followed for incident breast cancer through December 2002. We studied 215 postmenopausal breast cancer cases and 215 matched controls that were postmenopausal and not using exogenous hormones at the time of blood draw. EM were examined individually, grouped by pathway (hydroxylation at the C-2, C-4, or C-16 positions of the steroid ring), and by ratios of the groupings. Logistic regression models controlling for matching and breast cancer risk factors were used to calculate quartile-specific odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Significant elevated risks were not observed for individual EM, except for quartiles of 16-epiestriol (p trend =0.07). OR for total EM, the parent estrogens estrone and estradiol, and 2-pathway catechol EM (2-hydroxyestrone and 2-hydroxyestradiol) were elevated but trends were not statistically significant. Among 2-pathway metabolites, risks for the highest levels of 2-hydroxyestrone-3-methyl ether, and 2-methoxyestradiol were reduced; ORs for women in the highest vs. lowest quartiles were 0.57 (95% CI=0.33-0.99) and 0.53 (95% CI=0.30-0.96), respectively. Overall, women with higher levels of 2-pathway EM had a reduced risk of breast cancer, which remained after accounting for levels of parent EM, 4-pathway EM, and 16-pathway EM (all trends, p<0.11). CONCLUSIONS: Women with more extensive hydroxylation along the 2-pathway may have a reduced risk of postmenopausal breast cancer. Further studies are needed to clarify the risks for specific EM and complex patterns of estrogen metabolism. This will require aggregation of EM results from several studies.
  Breast cancer research: BCR 04/2013; 15(2):R34.
• Article: MicroRNA expression profiling of 51 human breast cancer cell lines reveals subtype and driver mutation-specific miRNAs.

  Muhammad Riaz, Marijn Tm van Jaarsveld, Antoinette Hollestelle, Wendy Jc Prager-van der Smissen, Anouk Aj Heine, Antonius Wm Boersma, Jingjing Liu, Jean Helmijr, Bahar Ozturk, Marcel Smid, Erik A Wiemer, John A Foekens, John Wm Martens
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  ABSTRACT: INTRODUCTION: Breast cancer is a genetically and phenotypically complex disease. To understand the role of microRNAs (miRNAs) in this molecular complexity, we performed miRNA expression analysis in a cohort of molecularly well-characterized human breast cancer (BC) cell lines to identify miRNAs associated with the most common molecular subtypes and the most frequent genetic aberrations. METHOD: Using a microarray carrying LNATM modified oligonucleotide capture probes (Exiqon), expression levels of 725 human miRNAs were measured in 51 BC cell lines. Differential miRNA expression was explored by unsupervised cluster analysis and then associated with the molecular subtypes and genetic aberrations commonly present in breast cancer. RESULTS: Unsupervised cluster analysis using the most variably expressed miRNAs divided the 51 BC cell lines into a major and a minor cluster predominantly mirroring the luminal and basal intrinsic subdivision of BC cell lines. One hundred and thirteen miRNAs were differentially expressed between these two main clusters. Forty miRNAs were differentially expressed between basal-like and normal-like/claudin-low cell lines. Within the luminal-group, 39 miRNAs were associated with ERBB2 overexpression and 24 with E-cadherin gene mutations, which are frequent in this subtype of BC cell lines. In contrast, 31 miRNAs were associated with E-cadherin promoter hypermethylation, which, contrary to E-cadherin mutation, is exclusively observed in BC cell lines that are not of luminal origin. Thirty miRNAs were associated with p16INK4 status while only a few miRNAs were associated with BRCA1, PIK3CA/PTEN and TP53 mutation status. Twelve miRNAs were associated with DNA copy number variation of the respective locus. CONCLUSIONS: Luminal-basal and epithelial-mesenchymal associated miRNAs determine the subdivision of miRNA transcriptome of BC cell lines. Specific sets of miRNAs were associated with ERBB2 overexpression, p16INK4a or E-cadherin mutation or E-cadherin methylation status, which implies that these miRNAs may contribute to the driver role of these genetic aberrations. Additionally, miRNAs, which are located in a genomic region showing recurrent genetic aberrations, may themselves play a driver role in breast carcinogenesis or contribute to a driver gene in their vicinity. In short, our study provides detailed molecular miRNA portraits of BC cell lines, which can be exploited for functional studies of clinically important miRNAs.
  Breast cancer research: BCR 04/2013; 15(2):R33.
• Article: Arthritis augments breast cancer metastasis: role of mast cells and SCF/c-Kit signaling.

  Lopamudra Das Roy, Jennifer M Curry, Mahnaz Sahraei, Dahlia M Besmer, Amritha Kidiyoor, Helen E Gruber, Pinku Mukherjee
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  ABSTRACT: INTRODUCTION: Breast cancer remains the second leading cause of cancer related deaths for women in the United States. Metastasis is regulated not only by intrinsic genetic changes in malignant cells, but also by the microenvironment, especially those associated with chronic inflammation. We have recently reported that mice that suffer from autoimmune arthritis have significantly increased incidence of bone and lung metastasis and decreased survival associated with breast cancer. In this study, we evaluated the mechanism underlying the increased metastasis. Methods We used two mouse models; one that develops spontaneous autoimmune arthritis (SKG mice) injected with metastatic breast cancer cells (4T1), and second, that develops spontaneous breast cancer (MMTV-PyV MT mice) injected with type II collagen to induce autoimmune arthritis. Mast cell levels and metastasis were monitored. RESULTS: First, we confirm that breast tumor-bearing arthritic mice have significantly higher incidence of bone and lung metastasis than their non-arthritic counterparts. Next, we show increased recruitment of mast cells within the primary tumor of arthritic mice which facilitate metastasis. Next, we report that arthritic mice without any tumors have higher numbers of mast cells in the bones and lungs which may be the underlying cause for the enhanced lung and bone metastasis observed in the arthritic mice. Next, we show that once the tumor cells populate the metastatic niches (bones and lungs), they further increase the mast cell population within the niche and assist in enhancing metastasis. This may primarily be due to the interaction of c-kit receptor present on mast cells and stem cell factor (SCF, the ligand for ckit) expressed on tumor cells. Finally, we show that targeting the SCF/cKit interaction with an anti-ckit antibody reduces the differentiation of mast cells and consequently reduces metastasis. CONCLUSION: This is the first report to show that mast cells may play a critical role in not only remodeling the tumor microenvironment but also the metastatic niche to facilitate efficient metastasis through SCF/cKit interaction in breast cancer with arthritis.
  Breast cancer research: BCR 04/2013; 15(2):R32.
• Article: Is TIMP-1 immunoreactivity alone or in combination with other markers a predictor of benefit from anthracyclines in the BR9601 adjuvant breast cancer chemotherapy trial?

  Alison F Munro, Annette Bartels, Eva Balslev, Christopher J Twelves, David A Cameron, Nils Brunner, John Ms Bartlett
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  ABSTRACT: INTRODUCTION: Predictive cancer biomarkers to guide the right treatment to the right patient at the right time are strongly needed. The purpose of the present study was to validate prior results that TIMP-1 alone or in combination with either HER2 or TOP2A copy number, can be used to predict benefit from epirubicin (E) containing chemotherapy compared with cyclophosphamide, methotrexate and fluorouracil (CMF) treatment. METHODS: For the purpose of this study, formalin fixed paraffin embedded tumor tissue from women recruited into the BR9601 clinical trial, that randomised patients to E-CMF versus CMF, were analysed for TIMP-1 immunoreactivity. Using previously collected data for HER2 amplification and TOP2A gene aberrations we defined patients as "anthracycline non-responsive" i.e.: 2T (TIMP-1 immunoreactive and TOP2A normal) and HT (TIMP-1 immunoreactive and HER2 negative) and anthracycline responsive (all other cases). RESULTS: In total 288 tumors were available for TIMP-1 analysis with (183/274) 66.8%, and (181/274) 66.0% being classed as 2T and HT responsive, respectively. TIMP-1 was neither associated with patient prognosis (recurrence free survival or overall survival) nor with a differential effect of E-CMF and CMF. Also, TIMP-1 did not add to the predictive value of HER2, TOP2A gene aberrations, or to Ki67 immunoreactivity. CONCLUSION: This study could not confirm the predictive value of TIMP-1 immunoreactivity in patients randomized to receive E-CMF versus CMF as adjuvant treatment for primary breast cancer.
  Breast cancer research: BCR 04/2013; 15(2):R31.
• Article: HIF-1alpha stimulates aromatase expression driven by prostaglandin E2 in breast adipose stroma.

  Nirukshi U Samarajeewa, Fangyuan Yang, Maria M Docanto, Minako Sakurai, Keely M McNamara, Hironobu Sasano, Stephen B Fox, Evan R Simpson, Kristy A Brown
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  ABSTRACT: INTRODUCTION: The majority of postmenopausal breast cancers are estrogen-dependent. Tumor-derived factors such as prostaglandin E2 (PGE2) stimulate CREB1 binding to cAMP response elements (CREs) on aromatase promoter II (PII), leading to the increased expression of aromatase and biosynthesis of estrogens within human breast adipose stromal cells (ASCs). Hypoxia inducible factor-1alpha (HIF-1alpha), a key mediator of cellular adaptation to low oxygen levels, is emerging as a novel prognostic marker in breast cancer. We have identified the presence of a consensus HIF-1alpha binding motif overlapping with the proximal CRE of aromatase PII. However, the regulation of aromatase expression by HIF-1alpha in breast cancer has not been characterized. This study aimed to characterize the role of HIF-1alpha in the activation of aromatase PII. METHODS: HIF-1alpha expression and localization were examined in human breast ASCs using QPCR, Western blotting, immunofluorescence and high content screening. QPCR and tritiated water-release assays were performed to assess the effect of HIF-1alpha on aromatase expression and activity. Reporter assays and ChIP were performed to assess the effect of HIF-1alpha on PII activity and binding. Treatments included PGE2 or DMOG (HIF-1alpha stabilizer). Double immunohistochemistry for HIF-1alpha and aromatase was performed on tissues obtained from breast cancer and cancer-free patients. RESULTS: Results indicate that PGE2 increases HIF-1alpha transcript and protein expression, nuclear localization and binding to aromatase PII in human breast ASCs. Results also demonstrate that HIF-1alpha significantly increases PII activity, and aromatase transcript expression and activity, in the presence of DMOG and/or PGE2, and that HIF-1alpha and CREB1 act co-operatively on PII. There is a significant increase in HIF-1alpha positive ASCs in breast cancer patients compared to cancer-free women, and a positive association between HIF-1 and aromatase expression. CONCLUSIONS: This study is the first to identify HIF-1alpha as a modulator of PII-driven aromatase expression in human breast tumor-associated stroma and provides a novel mechanism for estrogen regulation in obesity-related, post-menopausal breast cancer. Together with our on-going studies on the role of AMP-activated protein kinase (AMPK) in the regulation of breast aromatase, this work provides another link between disregulated metabolism and breast cancer.
  Breast cancer research: BCR 04/2013; 15(2):R30.
• Article: Closing escape routes: inhibition of IL-8 signaling enhances the anti-tumor efficacy of PI3K inhibitors.

  Ashish Juvekar, Gerburg M Wulf
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  ABSTRACT: The phosphoinositide 3-kinase (PI3K) pathway serves as a relay where signals that emanate from the cell membrane are received and converted into intracellular signals that promote proliferation and survival. Inhibitors of PI3K hold promise for the treatment of breast cancer because activation of this pathway is highly prevalent. However, as is increasingly observed with inhibitors of cell signaling, there appear to be mechanisms of primary and secondary resistance. Britschgi and colleagues report that compensatory activation of the IL-8 signaling axis is a mechanism of primary resistance to PI3K inhibitors in some triple-negative breast cancers. In a set of experiments that carefully emulate the clinical scenario in a mouse model, they show that simultaneous inhibition of Janus kinase 2 enhances the efficacy of PI3K/mammalian target of rapamycin inhibition. Their paper lends further support to the concept that successful design of treatments with signal transduction inhibitors must anticipate potential escape routes - and include agents to simultaneously block them.
  Breast cancer research: BCR 04/2013; 15(2):308.
• Article: A randomised controlled phase II trial of pre-operative celecoxib treatment reveals anti-tumour transcriptional response in primary breast cancer.

  Rita D Brandao, Juergen Veeck, Koen K Van de Vijver, Patrick Lindsey, Bart de Vries, Catharine Hmj van Elssen, Marinus J Blok, Kristien Keymeulen, Torik Ayoubi, Hubert Jm Smeets, Vivianne C Tjan-Heijnen, Pierre S Hupperets
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  ABSTRACT: INTRODUCTION: Cyclooxygenase-2 (COX-2) is frequently over-expressed in primary breast cancer. In transgenic breast cancer models, over-expression of COX-2 leads to tumour formation while COX-2 inhibition exerts anti-tumour effects in breast cancer cell lines. To further determine the effect of COX-2 inhibition in primary breast cancer, here we aimed at identifying transcriptional changes in breast cancer tissues of patients treated with the selective COX-2 inhibitor celecoxib. METHODS: In a single-centre double-blinded phase II study, thirty-seven breast cancer patients were randomised to receive either pre-operative celecoxib (400 mg) twice daily for two to three weeks (n = 22) or a placebo likewise (n = 15). Gene expression in fresh-frozen pre-surgical biopsies (before treatment) and surgical excision specimens (after treatment) was profiled by using Affymetrix arrays. Differentially expressed genes and altered pathways were bioinformatically identified. Expression of selected genes was validated by quantitative PCR (qPCR). Immunohistochemical protein expression analyses of the proliferation marker Ki-67, the apoptosis marker cleaved caspase-3, and the neo-angiogenesis marker CD34 served to evaluate biological response. RESULTS: We identified 972 and 586 significantly up- and down-regulated genes, respectively, in celecoxib-treated specimens. Significant expression changes in six out of eight genes could be validated by qPCR. Pathway analyses revealed over-representation of deregulated genes in the networks of proliferation, cell cycle, extracellular matrix biology, and inflammatory immune response. The Ki-67 mean change relative to baseline was -29.1% (P = 0.019) and -8.2% (P = 0.384) in the treatment and control arm, respectively. Between treatment groups, the change in Ki-67 was statistically significant (P = 0.029). Cleaved caspase-3 and CD34 expression were not significantly different between the celecoxib-treated and placebo-treated group. CONCLUSIONS: Short-term COX-2 inhibition by celecoxib induces transcriptional programs supporting an anti-tumour activity in primary breast cancer tissue. The impact on proliferation-associated genes is reflected by a reduction of Ki-67 positive cells. Therefore, COX-2 inhibition should be considered as treatment strategy for further clinical testing in primary breast cancer. Trial registration: ClinicalTrials.gov NCT01695226.
  Breast cancer research: BCR 04/2013; 15(2):R29.
• Article: The Hedgehog signalling pathway in breast development, carcinogenesis and cancer therapy.

  Mun Hui, Aurélie Cazet, Radhika Nair, D Neil Watkins, Sandra A O'Toole, Alexander Swarbrick
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  ABSTRACT: Despite the progress achieved in breast cancer screening and therapeutic innovations, the basal-like subtype of breast cancer (BLBC) still represents a particular clinical challenge. In order to make an impact on survival in this type of aggressive breast cancer, new targeted therapeutic agents are urgently needed. Aberrant activation of the Hedgehog (Hh) signalling pathway has been unambiguously tied to cancer development and progression in a variety of solid malignancies, and the recent approval of vismodegib, an orally bioavailable small-molecule inhibitor of Smoothened, validates Hh signalling as a valuable therapeutic target. A number of recent publications have highlighted a role for Hh signalling in breast cancer models and clinical specimens. Interestingly, Hh ligand overexpression is associated with the BLBC phenotype and a poor outcome in terms of metastasis and breast cancer-related death. In this review, we provide a comprehensive overview of the canonical Hh signalling pathway in mammals, highlight its roles in mammary gland development and breast carcinogenesis and discuss its potential therapeutic value in BLBC.
  Breast cancer research: BCR 03/2013; 15(2):203.
• Article: Expression of Quiescin Sulfhydryl Oxidase 1 is associated with a highly invasive phenotype and correlates with a poor prognosis in Luminal B breast cancer.

  Benjamin A Katchman, I Tolgay Ocal, Heather E Cunliffe, Yu-Hui H Chang, Galen Hostetter, Aprill Watanabe, Janine Lobello, Douglas F Lake
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  ABSTRACT: INTRODUCTION: Quiescin sulfhydryl oxidase 1 (QSOX1) oxidizes sulfhydryl groups to form disulfide bonds in proteins. Tumor specific expression of QSOX1 has been reported for numerous tumor types. In this study, we investigate QSOX1 as a marker of breast tumor progression and evaluate the role of QSOX1 as it relates to breast tumor growth and metastasis. METHODS: Correlation of QSOX1 expression with breast tumor grade, subtype, and Estrogen Receptor (ER) status was gathered through informatic analysis using the "Gene Expression Based Outcome for Breast Cancer Online" (GOBO) web-based tool. Expression of QSOX1 protein in breast tumors tissue microarray (TMA) and in a panel of breast cancer cell lines was used to confirm our informatics analysis. To investigate malignant cell mechanisms for which QSOX1 might play a key role, we suppressed QSOX1 protein expression using short hairpin (sh) RNA in ER+ Luminal A-like MCF7, ER+ Luminal B-like BT474 and ER- Basal-like BT549 breast cancer cell lines. RESULTS: GOBO analysis revealed high levels of QSOX1 RNA expression in ER+ subtypes of breast cancer. In addition, Kaplan Meyer analyses revealed QSOX1 RNA as a highly significant predictive marker for both relapse and poor overall survival in Luminal B tumors. We confirmed this finding by evaluation of QSOX1 protein expression in breast tumors and in a panel of breast cancer cell lines. Expression of QSOX1 in breast tumors correlates with increasing tumor grade and high Ki-67 expression. Suppression of QSOX1 protein slowed cell proliferation as well as dramatic inhibition of MCF7, BT474 and BT549 breast tumor cells from invading through Matrigel in a modified Boyden chamber assay. Inhibition of invasion could be rescued by the exogenous addition of recombinant QSOX1. Gelatin zymography indicated that QSOX1 plays an important role in function of MMP-9 a key mediator of breast cancer invasive behavior. CONCLUSIONS: Taken together, our results suggest that QSOX1 is a novel biomarker for risk of relapse and poor survival in Luminal B breast cancer, and has a pro-proliferative and pro-invasive role in malignant progression partly mediated through a decrease in MMP-9 functional activity.
  Breast cancer research: BCR 03/2013; 15(2):R28.
• Article: Elf5 - breast cancer's little helper.

  Hayley T Frend, Christine J Watson
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  ABSTRACT: A variety of transcription factors has been shown to regulate lineage commitment in the mammary gland and to be associated with different molecular subtypes of breast cancer. E74-like factor 5 (Elf5) has now been identified as a marker of oestrogen receptor status, and high expression correlates with more aggressive basal cancers and resistance to anti-oestrogens. Manipulation of Elf5 transcript levels perturbs the molecular profiles of luminal and basal subtypes, highlighting the possibility that targeting Elf5 could provide a new approach for the treatment of basal cancers.
  Breast cancer research: BCR 03/2013; 15(2):307.