bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract A15: Using genetic and pharmacological methods to explore role of the methyltransferase Ezh2 in mouse mammary tumorigenesis
Authors: Hirukawa Alison , Smith Harvey , Muller William 
Published: May 2016

Abstract
ErbB2 (HER2/Neu) is a receptor tyrosine kinase over expressed in 20-30% of primary human breast cancer cancer, and correlated with poor clinical outcome. However, the mechanisms through which ErbB2 contributes to tumorigenesis and poor patients prognosis is unclear. Over the last decade, several lines of evidence have demonstrated that the transformation of a normal epithelial cells to a malignant phenotype requires the accumulation of multiple genetics and epigenetic events, including post translational modifications of histones. Enhancer of Zeste 2 (Ezh2) is a polycomb group protein that, as a part of the PRC2 complex mediates gene silencing through tri-methylation of lysine 27 on histone 3 (H3K27me3). Interestingly, several clinical studies have reported EZH2 transcript and protein levels to be elevated in aggressive human breast carcinomas.
To investigate the requirement of Ezh2 in mouse mammary epithelial tumour initiation, we have crossed an Ezh2 conditional knock out mouse strain to a tetracycline inducible mammary epithelium specific Polyoma virus Middle T (PyVmT) transgenic mouse strain. The PyVmT model provides insight into how active receptor tyrosine kinase signalling can direct cellular transformation and its benefits include rapid tumour onset and well characterized disease progression, while the tetracycline-inducible systems allows for bypassing any developmental defects in the mammary gland due to Ezh2 ablation. Tumour onset in Ezh2 deficient mice are delayed(t50=135 days, n=15) compared to the wild type cohort (t50=63, n=28), and less multifocal in comparison to the wild type cohorts. End point tumours in Ezh2 deficient mice upregulate transcriptional signatures related to fibrosis and matrix remodelling, lipid biogenesis and cell cycle regulation. To compliment our genetic studies, we have also acquired a potent Ezh2 inhibitor, GSK126, to target the methyl transferase activity of Ezh2 in vivo and in vitro. Preliminary results indicate that the effect of global H3K27me3 loss is more pronounced during tumour initiation than tumour maintenance, and that in vivo effects of GSK-126 administration are likely mediated by the immune system.
Genetic studies will allow for us to dissect how Ezh2 (through H3K27me3) controls transcriptional programs during tumour initiation and maintenance. In combination with the development of a highly selective and potent Ezh2 inhibitor, GSK126, combined pharmaceutical studies and the use of genetic models will provide insight into potential therapeutic windows during disease progression.
Citation Format: Alison Hirukawa, Harvey Smith, William Muller. Using genetic and pharmacological methods to explore role of the methyltransferase Ezh2 in mouse mammary tumorigenesis. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research; Oct 17-20, 2015; Bellevue, WA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(2_Suppl):Abstract nr A15.
Abstract A24: Age- and lineage-dependent gene expression is maintained by microenvironment imposed epigenetic states in human mammary epithelial cells
Authors: Miyano Masaru , Stoiber Marcus , Stampfer Martha , Brown Ben , LaBarge Mark A. 
Published: May 2016

Abstract
Normal healthy tissues show changing patterns of gene expression as a consequence of aging, and there is a functional cost to these changes that can be relevant to disease pathology. The most obvious age-related disease in breast is cancer, with the large majority of newly diagnosed breast cancer occuring in women over 50. We have shown that breast gene expression changes that occur with age have functional consequences in the epithelial progenitor and differentiated cells, i.e, a decline of the myoepithelial lineage, loss of luminal cell specificity, and accumulation of differentiation defective multipotent progenitor cells. We have hypothesized that these tissue-level changes make older epithelia more susceptible to transformation. Because gene expression patterns reflect the wiring and response diagrams of cells, it is of central importance to understand the origins of age-related transcriptomes. In our studies, early passage normal human mammary epithelial cells (HMEC) show age-dependent functional and molecular hallmarks consistent with in vivo, suggesting that the underlying gene expression patterns are metastable. DNA methylation is a stable, but malleable, form of epigenetic regulation that may underpin these biologically metastable states. Genome-wide analysis of primary epithelia was used to identify a set of genes that exhibit age- and lineage-specific expression that was inversely correlated with promoter CpG methylation. Chemical perturbation of DNA methylation in pre-menopausal HMEC resulted in a biochemical phenocopy of more advanced age. Tissue-mimetic cultures were used to demonstrate that lineage-specific gene expression and methylation in luminal cells were imposed by distinct microenvironments. Optimal maintenance of the luminal phenotype required direct contact with the apical surface of myoepithelial cells. Mimetic tissues built with HMEC that differed in chronological donor age revealed that age-dependent gene expression and methylation patterns are communicated between the two different lineages, as exposure of pre-menopausal luminal cells to a post-menopausal microenvironment imposed transcriptional patterns in luminal cells consistent with post-menopause. These data demonstrate that lineage- and age-dependent phenotypes in HMEC are maintained by microenvironment-imposed metastable epigenetic states.
Note: This abstract was not presented at the conference.
Citation Format: Masaru Miyano, Marcus Stoiber, Martha Stampfer, Ben Brown, Mark A. LaBarge. Age- and lineage-dependent gene expression is maintained by microenvironment imposed epigenetic states in human mammary epithelial cells. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research; Oct 17-20, 2015; Bellevue, WA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(2_Suppl):Abstract nr A24.
Abstract A25: Cytometric atlas of the human breast: Comprehensive characterization reveals 12 distinct cell populations
Authors: Hines William Curtis , Carr Ambrose , Thi Kate , Wan Zhenmao , Pe'er Dana , Bissell Mina J. 
Published: May 2016

Abstract
Since formulation of the cellular theory in the early 19th century—relatively not so long ago—it has become universally recognized that tissues and organisms are formed and shaped by cells of many different types, all operating in beautiful harmony. Many mechanisms of this orchestration remain largely a mystery to this day, yet are important for us to understand if we are to fully comprehend fundamental processes in disease, especially one as formidable and perplexing as cancer. In the current era of progressive technological advances, many areas of biology are converging, and we now recognize and expect differences between cells, even among those of the same type, but whose origins rest in different tissues. Yet, many core tenets are being universally applied. The detailed cellular composition of tissues is clouded with uncertainty for many tissue types, and this includes the breast. To clarify the cell types in the breast and build a solid foundation for future work, we have meticulously examined a large collection of normal breast tissues, microscopically and by flow cytometry. We developed a complex antibody panel and rigorous gating strategy capable of objectively resolving and sorting each major cell type. We have sequenced mRNAs expressed by even the rarest of cell subpopulations and refined or developed methods for culturing each. This includes: several different luminal and epithelial fractions, myoepithelial cells, adipocytes, leukocytes, pericytes, erythrocytes, adipose-derived mesenchymal stem cells, and both lymphatic and vascular endothelial cells –12 different types in all. Future studies are aimed at developing heterotypic culture models using these cells, but also to use our new knowledge and experience to similarly explore heterogeneity of ductal carcinoma in situ (DCIS) and invasive breast cancers. We will present the development of this method and characterization to date of the sorted cell populations.
Citation Format: William Curtis Hines, Ambrose Carr, Kate Thi, Zhenmao Wan, Dana Pe'er, Mina J. Bissell. Cytometric atlas of the human breast: Comprehensive characterization reveals 12 distinct cell populations. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research; Oct 17-20, 2015; Bellevue, WA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(2_Suppl):Abstract nr A25.
Abstract A29: Detection of ultra-rare mutations during breast stem cell tumor progression by Duplex Sequencing
Authors: Ahn Eun Hyun , Hirohata Kensen , Lee Seung Hyuk , Kim Joon Yup , Kohrn Brendan F. , Fox Edward J. , Chang Chia-Cheng , Loeb Lawrence A. 
Published: May 2016

Abstract
Most studies have mainly investigated clonal mutations due to the high background error frequencies of conventional next generation sequencing (NGS) methods. We have established a new method termed Duplex Sequencing (DS) that detects mutations with unprecedented accuracy and enables us to detect sub-clonal and rare mutations as well as clonal mutations. Using DS, we present our first genome-wide analysis of mitochondrial (mt) DNA mutations during the transformation of human normal breast stem cells to tumorigenic cells. We used a model system to dissect sequential steps in the progression of normal stem cells to tumorigenic cells. Significant differences have been found among normal stem cells, immortal cells, and tumorigenic cells. These cells differ in putative breast cancer stem cell (CSC) populations, mtDNA copy numbers, and the frequencies and types of mutations. We found that putative CSCs and mtDNA copy numbers increase as normal stem cells become tumorigenic cells. The vast majority of mutations identified in our study are stochastic (rare mutations) and the frequency of rare mutations is lower in transformed cells than in normal stem cells. This lower rare mutation load in transformed cells induces lower scores of predicted pathogenicity in transformed cells than in normal stem cells. C&gt;T/G&gt;A and A&gt;G/T&gt;C transitions are the major mutation types in normal stem cells, while only C&gt;T/G&gt;A are the major mutation types in transformed cells. Using DS, we detected a total of 1220 rare mutations and 678 of these variants have not been reported previously. The mtDNA mutation spectra of breast tumorigenic cells correlate with published nuclear DNA mutation signatures, which are found in the majority of tumors. We have identified mutations that can serve as potential biomarkers that indicate the different stages of breast carcinogenesis. These significant differences in mutation profiles could aid in characterizing different phenotypes between normal stem cells and transformed cells.
Citation Format: Eun Hyun Ahn, Kensen Hirohata, Seung Hyuk Lee, Joon Yup Kim, Brendan F. Kohrn, Edward J. Fox, Chia-Cheng Chang, Lawrence A. Loeb. Detection of ultra-rare mutations during breast stem cell tumor progression by Duplex Sequencing. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research; Oct 17-20, 2015; Bellevue, WA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(2_Suppl):Abstract nr A29.
Abstract A39: A role for src kinase in estrogen receptor-positive breast cancer
Authors: Abdullah Christopher , Korkaya Hasan , Courtneidge Sara A. 
Published: May 2016

Abstract
Estrogen (E2) stimulation promotes proliferation in estrogen receptor-positive (ER+) breast cancer, which accounts for 60-75% of all breast cancer. E2 signals through the ER via three pathways: the classical genomic pathway involving transcriptional activation of the ER, crosstalk between ER and other transcription factors, and “non-genomic” signaling cascades, which do not involve the transcriptional activity of the ER. This “non-genomic” pathway likely involves Src family kinases (SFKs) and has been implicated in cell cycle progression in fibroblasts engineered to express the ER (Castoria 1999). While not typically amplified or mutationally activated in ER+ breast cancer, Src is hyperactive in most breast cancers.
To test whether SFK activity is required for G1/S cell cycle progression in breast cancer cells, we pretreated quiescent ER+ MCF7 or ZR75-1 cells with a selective SFK inhibitor (SU11333) prior to stimulation with E2. Inhibition of SFK activity blocked progression from G1 to S phase. Previous data from our laboratory has demonstrated that G1/S progression in response to peptide growth factor stimulation of quiescent fibroblasts is dependent upon SFK-mediated stabilization of myc mRNA (Bromann 2005). We therefore tested whether SFK activity also regulates myc expression in breast cancer cells. Our data suggest that SFK activity is required for accumulation of myc mRNA in quiescent MCF7s after E2 stimulation, and that E2 stimulated stabilization of myc mRNA is dependent on SFK activity. We are currently investigating the mechanism involved in stabilizing myc mRNA levels.
References:
Castoria et al. EMBO J, 1999
Bromann et al. JBC, 2005
Citation Format: Christopher Abdullah, Hasan Korkaya, Sara A. Courtneidge. A role for src kinase in estrogen receptor-positive breast cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research; Oct 17-20, 2015; Bellevue, WA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(2_Suppl):Abstract nr A39.
Abstract B07: Mcl-1-mediated resistance to ABT-263 is combated by mTOR inhibition in luminal breast cancers
Authors: Williams Michelle M. , Lee Linus , Morrison Meghan M. , McKernan Courtney , Sanchez Violeta , Hicks Donna , Stricker Thomas , Cook Rebecca S. 
Published: May 2016

Abstract
In the context of cancer, the intrinsic apoptotic pathway is exploited to favor tumor cell survival through overexpression of anti-apoptotic Bcl-2 family members (Bcl-A1, Bcl-2, Bcl-xL, Bcl-w and Mcl-1). We investigated targeting of anti-apoptotic Bcl-2 proteins in a panel of human luminal breast cancer cell lines. Use of ABT-263, the Bcl-2/Bcl-xL/Bcl-w inhibitor, induced transient tumor cell killing and decreased tumor cell growth in only 1 of 4 cell lines in three dimensional (3D) cultures. Mcl-1 expression and activity were rapidly upregulated upon ABT-263 treatment, highlighting the compensatory nature of Mcl-1. In luminal breast cancers, Mcl-1 was the most frequently amplified anti-apoptotic Bcl-2 family member according to The Cancer Genome Atlas, while nearly 80% of the luminal breast tumor epithelium was positive for Mcl-1 in a tissue microarray. Thus, we hypothesized that Mcl-1 may be a dominant tumor cell survival factor in luminal breast cancers.
Use of the mTOR inhibitor RAD001 (everolimus) to target Mcl-1 indirectly decreased tumor cell growth and increased tumor cell killing in 3 of 4 cell lines, as well as WAP-Myc luminal mammary tumors, demonstrating the effectiveness of Mcl-1 as a therapeutic target in breast cancers. While Mcl-1 inhibition alone did not affect growth of T47D cells, robust growth inhibition and tumor cell killing were seen in all cell lines upon inhibition of Mcl-1 using RAD001 or a EIF4 complex inhibitor (4E1RCat) in combination with ABT-263, suggesting that the induction of Mcl-1 upon ABT-263 treatment may be supported by increased cap-dependent translation. These results demonstrate that the sensitivity of luminal breast cancers to ABT-263 is enhanced by Mcl-1 inhibition, warranting further investigation into inhibition of anti-apoptotic Bcl-2 family proteins, in particular Mcl-1, as a clinical strategy to improve survival of patients with luminal breast cancers.
Citation Format: Michelle M. Williams, Linus Lee, Meghan M. Morrison, Courtney McKernan, Violeta Sanchez, Donna Hicks, Thomas Stricker, Rebecca S. Cook. Mcl-1-mediated resistance to ABT-263 is combated by mTOR inhibition in luminal breast cancers. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research; Oct 17-20, 2015; Bellevue, WA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(2_Suppl):Abstract nr B07.
Abstract B15: Semaphorin 7a exerts pleiotropic effects to promote breast tumor progression
Authors: Black Sarah , Nelson Andrew , Gurule Natalia , Futscher Bernard , Lyons Traci R. 
Published: May 2016

Abstract
Understanding what drives breast tumor progression is of utmost importance for blocking tumor metastasis. We have identified that semaphorin 7a is a potent driver of breast tumor progression. Semaphorin 7a is a GPI membrane anchored protein that promotes attachment and spreading in multiple cell types. We observe that increased expression of SEMA7A occurs in ~45%human breast cancers and its upregulation is associated with decreased overall and distant metastasis free survival. In both in vitro and in vivo models, shRNA mediated silencing reveals roles for semaphorin 7a in the promotion of breast cancer cell growth, motility, and invasion as well as in lymphangiogenesis. Our studies also uncover a relationship between COX-2 and semaphorin 7a expression, and suggest that semaphorin 7a promotes tumor cell invasion on collagen and lymphangiogenesis via activation of β1-integrin receptor. Our results suggest that semaphorin 7a, may be novel target for blocking breast tumor progression.
Citation Format: Sarah Black, Andrew Nelson, Natalia Gurule, Bernard Futscher, Traci R. Lyons. Semaphorin 7a exerts pleiotropic effects to promote breast tumor progression. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research; Oct 17-20, 2015; Bellevue, WA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(2_Suppl):Abstract nr B15.
Abstract B60: The clinical significance and molecular features of the spatial tumor shapes in breast cancers
Authors: Moon Hyeong-Gon , Kim Namshin , Lee Minju , Moon HyunHye , Yoo Tae-Kyung , Lee Han-Byoel , Kim Jisun , Noh Dong-Young , Han Wonshik 
Published: May 2016

Abstract
Background: Each breast cancer has its unique spatial shape, but the clinical importance and the underlying mechanism for the three-dimensional tumor shapes are mostly unknown.
Methods: We collected the data on the three-dimensional tumor size and tumor volume data of invasive breast cancers from 2,250 patients who underwent surgery between Jan 2000 and Jul 2007. The degree of tumor eccentricity was estimated by using the difference between the spheroid tumor volume and ellipsoid tumor volume (spheroid-ellipsoid discrepancy, SED). In 39 patients, transcriptome and exome sequencing data obtained.
Results: Estimation of more accurate tumor burden by calculating ellipsoid tumor volumes did not improve the outcome prediction when compared to the traditional longest diameter measurement. However, the spatial tumor eccentricity, which was measured by SED, showed significant variation between the molecular subtypes of breast cancer. Additionally, the degree of tumor eccentricity was associated with well-known prognostic factors of breast cancer such as tumor size and lymph node metastasis. Transcriptome data from 39 patients showed significant association between genes involved in metal/ion binding, nucleotide binding, and extracellular matrix, and the degree of tumor eccentricity.
Conclusion: The present study validates the usefulness of the current tumor size method in determining tumor stages. Furthermore, we show that the tumors with high eccentricity are more likely to have aggressive tumor characteristics. Genes involved in the extracellular matrix remodeling are candidate regulators of the spatial tumor shapes in breast cancer.
Citation Format: Hyeong-Gon Moon, Namshin Kim, Minju Lee, HyunHye Moon, Tae-Kyung Yoo, Han-Byoel Lee, Jisun Kim, Dong-Young Noh, Wonshik Han. The clinical significance and molecular features of the spatial tumor shapes in breast cancers. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research; Oct 17-20, 2015; Bellevue, WA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(2_Suppl):Abstract nr B60.
Abstract B70: p16 and 9p21 deletion are largely unrelated but linked to unfavorable tumor phenotype in breast cancer
Authors: Lebok Patrick , Roming Magdalena , Kluth Martina , Koop Christina , Oezden Cansu , Taskin Brevian , Hussein Khakan , Lebeau Anette , Witzel Isabell , Mahner Sven , Geist Stefan , Paluchowski Peter , Wilke Christian , Heilenkoetter Uwe , Mueller Volkmar , Simon Ronald , Sauter Guido , Terracciano Luigi , Krech Rainer , Assen Albert von der , Burandt Eike 
Published: May 2016

Abstract
Overexpression of the p16 tumor suppressor, but also deletion of its gene locus 9p21, has been linked to unfavorable tumor phenotype and poor patient outcome in breast cancer. To better understand these seemingly contradictory observations, and the prognostic impact of p16 expression and 9p21 deletion in breast cancer, we analyzed a tissue microarray (TMA) with 2,197 breast cancers by fluorescence in-situ hybridization (FISH) using a CDKN2A-specific probe and by p16 immunohistochemistry. p16 immunostaining was typically uniform and considered weak in 25.6%, moderate in 7.1%, and strong in 12.7% of 1,684 analyzable cancers. Strong p16 staining was significantly linked to advanced tumor stage (p=0.0003), high-grade (p&lt;0.0001), high tumor cell proliferation (p&lt;0.0001), negative hormone receptor (ER/PR) status (p&lt;0.0001 each), and shortened overall survival (p=0.0038). 9p21 deletion was found in 15.3% of 1,089 analyzable breast cancers, including 1.7% homozygous and 13.6% heterozygous deletions. 9p21 deletion was significantly linked to adverse tumor features, including high-grade (p&lt;0.0001) and nodal positive cancers (p=0.0063), high cell proliferation (p&lt;0.0001), negative hormone receptor (ER/PR) status (p≤0.0006), and HER2 amplification (p=0.0078). Patient outcome was also worse in p16 deleted than in undeleted cancers but this difference did not reach statistical significance (p=0,0720). p16 expression was absent in cancers harboring homozygous 9p21 deletions. However, a striking difference in p16 expression was not found between cancers with (59.2% p16 positive) and without heterozygous 9p21 deletion (51.3% p16 positive, p=0.0256). In conclusion, p16 expression is unrelated to 9p21 deletion, but both alterations are linked to aggressive breast cancer phenotype. High level p16 expression is a strong predictor of unfavorable disease course in breast cancer.
Citation Format: Patrick Lebok, Magdalena Roming, Martina Kluth, Christina Koop, Cansu Oezden, Brevian Taskin, Khakan Hussein, Anette Lebeau, Isabell Witzel, Sven Mahner, Stefan Geist, Peter Paluchowski, Christian Wilke, Uwe Heilenkoetter, Volkmar Mueller, Ronald Simon, Guido Sauter, Luigi Terracciano, Rainer Krech, Albert von der Assen, Eike Burandt. p16 and 9p21 deletion are largely unrelated but linked to unfavorable tumor phenotype in breast cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research; Oct 17-20, 2015; Bellevue, WA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(2_Suppl):Abstract nr B70.