Breast Epithelium Research Articles

Gene expression signature of atypical breast hyperplasia and regulation by SFRP1

BackgroundAtypical breast hyperplasias (AH) have a 10-year risk of progression to invasive cancer estimated at 4–7%, with the overall risk of developing breast cancer increased by ~ 4-fold. AH lesions are estrogen receptor alpha positive (ERα+) and represent risk indicators and/or precursor lesions to low grade ERα+ tumors. Therefore, molecular profiles of AH lesions offer insights into the earliest changes in the breast epithelium, rendering it susceptible to oncogenic transformation.MethodsIn this study, women were selected who were diagnosed with ductal or lobular AH, but no breast cancer prior to or within the 2-year follow-up. Paired AH and histologically normal benign (HNB) tissues from patients were microdissected. RNA was isolated, amplified linearly, labeled, and hybridized to whole transcriptome microarrays to determine gene expression profiles. Genes that were differentially expressed between AH and HNB were identified using a paired analysis. Gene expression signatures distinguishing AH and HNB were defined using AGNES and PAM methods. Regulation of gene networks was investigated using breast epithelial cell lines, explant cultures of normal breast tissue and mouse tissues.ResultsA 99-gene signature discriminated the histologically normal and AH tissues in 81% of the cases. Network analysis identified coordinated alterations in signaling through ERα, epidermal growth factor receptors, and androgen receptor which were associated with the development of both lobular and ductal AH. Decreased expression of SFRP1 was also consistently lower in AH. Knockdown of SFRP1 in 76N-Tert cells resulted altered expression of 13 genes similarly to that observed in AH. An SFRP1-regulated network was also observed in tissues from mice lacking Sfrp1. Re-expression of SFRP1 in MCF7 cells provided further support for the SFRP1-regulated network. Treatment of breast explant cultures with rSFRP1 dampened estrogen-induced progesterone receptor levels.ConclusionsThe alterations in gene expression were observed in both ductal and lobular AH suggesting shared underlying mechanisms predisposing to AH. Loss of SFRP1 expression is a significant regulator of AH transcriptional profiles driving previously unidentified changes affecting responses to estrogen and possibly other pathways. The gene signature and pathways provide insights into alterations contributing to AH breast lesions.

The novel diterpene 7β-acetoxy-20-hydroxy-19,20-epoxyroyleanone from Salvia corrugata shows complex cytotoxic activities against human breast epithelial cells

AimsThe aim of this study was the characterization of the in vitro cytotoxic properties of a recently isolated diterpene compound, 7β-acetoxy-20-hydroxy-19,20-epoxyroyleanone (compound 1), extracted from Salvia corrugata, versus human cell lines. Main methodsWe used as model study immortalized breast epithelial cells MCF10A and two ERBB2+ breast cancer (BCa) cell lines, SKBR-3 and BT474. Compound 1 was isolated by methanolic extraction from regenerated shoots of Salvia corrugata Vahl, and purified by high pressure liquid chromatography (HPLC). Flow cytometry (FCM) was employed for cell cycle, apoptosis and reactive oxygen species (ROS) analysis. Cell morphology was assessed by immunofluorescence and transmission electron microscopy (TEM). Key findingsCompound 1 inhibited cell survival of all breast cell lines. In particular, compound 1 promoted cell cycle arrest in the G0/G1 phase and apoptosis along with impairment of the mitochondrial function, which was reflected in a gross alteration of the mitochondrial network structure. Furthermore, we also detected a potent activation of the ERK1/2 kinase, which suggested the induction of reactive oxygen species (ROS). Partial rescue of survival obtained with n-acetylcysteine (NAC) when coadminstered with compound 1 further supported a contribution of ROS mediated mechanisms to the growth-arrest and proapoptotic activity of compound 1 in both BCa cell lines. ROS production was indeed confirmed in SKBR-3. SignificanceOur findings show that compound 1 has a cytotoxic activity against both human normal and cancer cell lines derived from breast epithelia, which is mediated by ROS generation and mitochondrial damage.

Molecular profiling of microinvasive breast cancer microenvironment progression

BackgroundTumors develop by progression through a series of stages. Every cell of the tumor microenvironment is constantly changing in the flow of the cancer progression. It has become clear in recent years that stroma is essential for tumor maintenance and growth. Here, we aimed to give a chronological order of gene expression changes given in the dynamical framework of microinvasive breast cancer microenvironment.MethodsRNA-seq was performed on seven microinvasive breast cancers. For each of them we microdissected seven different portions of the tumor, four related to the breast epithelium and three to the stroma. Breast epithelium was chronologically subdivided in normal breast epithelium (NBE), carcinoma in situ (CIS), emerging invasive fingers (EIF) and invasive breast cancer (IBC). For each of the breast epithelium subdivisions we collected the adjacent stroma (S): S-NBE, S-EIF and S-IBC.ResultsThe overall differentially expressed genes (DEGs) in all the compartments were analysed and evaluated to understand the pathways involved in tumor progression. Then we analysed the DEGs of the epithelial and stromal portions in comparison with the normal portions. We observed that the stromal cells are necessary for the development and the maintenance of the tumor, especially in tumor progression. Moreover the most important genes involved in the main metabolic pathways were analysed and the communications within the different cell compartments were highlighted.ConclusionsAs a future perspective, a deeply study of the identified key genes, particularly in the stromal cells, will be crucial to develop an anticancer therapy that is undergoing a conversion from a cancer cell-centric strategy to a stroma-centric strategy, more genomically stable.

Omega-3 fatty acids and ERPR(-) and HER2/neu(+/-) breast cancer prevention.

TPS1589 Background: The most aggressive breast cancer subtypes tend to be estrogen and progesterone receptor negative (ERPR(-)) and human epidermal growth factor receptor type 2 positive (HER2(+)). Women with these breast cancer subtypes (triple negative, ERPR(-)HER2(+)) tend to experience worse clinical outcomes and have a relatively higher risk of recurrence. Our previous research demonstrated that dietary omega-3 (n-3) fatty acids can significantly inhibit ERPR(-) HER2(+) tumorigenesis in MMTV-HER2/neu transgenic mice fed fish oil vs corn oil-based diets. The fish oil diet group developed 30% fewer breast tumors, had lower Ki67 expression, and experienced less mammary atypia relative to the corn oil diet group. Other studies involving diet, nutrition and breast cancer point to the potentially protective effect of an anti-inflammatory diet on the risk of developing ER(-) and HER2(+) breast cancer, further supporting the evidence that the ERPR(-), HER2(±) subtypes may be highly responsive to this bioactive nutrient. Methods: This is a double-blinded, randomized clinical trial of high dose (~5.4 g EPA+DHA) vs low dose (~0.9 g EPA+DHA in fatty acid mix of the typical American diet) of n-3 fatty acids in breast cancer survivors of ERPR(-), HER2(±) breast cancer. Eligible participants will take 5 capsules/day for 12 months, with cellular samples of breast epithelial and/or adipose tissue obtained by fine needle aspirations of the contralateral breast. The study aims to determine whether n-3 fatty acid supplementation will modify fatty acid metabolite content in breast adipose tissue, modulate cytomorphology and/or cell proliferation in breast epithelial cells, affect DNA methylation patterns, and modulate pro- vs anti-inflammatory gene expression patterns in breast adipose tissue. Correlative aims will evaluate possible associations between factors such as breast adipose tissue, red cell membrane fatty acid profiles, BMI, and reported dietary intake. Sample size of 40 participants per arm was calculated to provide at least 80% power to detect a statistically significant difference for each primary endpoint. This study focuses on women survivors of high risk breast cancer subtypes, specifically triple negative or ERPR(-)HER2(+) disease, who are currently without long term adjuvant options. Eligibility criteria include prior diagnosis of ERPR(-) stage 0 to III breast cancer, ≤5 years from completion of standard therapy.The study was closed to accrual in November 2018; less than 9 months of follow-up remain for active study participants. Clinical trial information: NCT02295059.

The Impact of Partial Weak Staining in Normal Breast Epithelium on the Reliability of Immunohistochemistry Results in HercepTest-positive Breast Cancer

IntroductionAlthough normal epithelial cells do not show human epidermal growth factor receptor-2 (HER2) gene amplification and should lack membrane staining by HER2 immunohistochemistry (IHC), HER2 staining in benign breast epithelium is occasionally encountered. The significance of this occurrence has not yet been adequately studied, and its associated American Society of Clinical Oncology/College of American Pathologists recommendations are vague. Our objective is to assess the correlation between HER2 IHC 3+ breast cancer cases with normal epithelium staining (NES) and their corresponding fluorescence in situ hybridization (FISH) results, and to suggest recommendations for interpretation. Materials and MethodsA total of 154 breast cancer cases with HER2 IHC 3+ were reviewed. NES, along with other clinicopathologic characteristics, were recorded. NES was scored as present or absent. All study cases were sent for FISH testing. All cases, and particularly those that showed false positivity for IHC (positive IHC, negative FISH) were examined for NES. ResultsOf the 154 cases, 146 cases were FISH-positive (94.8%) and 2 failed FISH testing (1.3%). Conversely, 22% (34/154) of the cases showed NES for HER2. Of these 34 cases, 23 (67%) were FISH-amplified, 9 (26%) were FISH not amplified, and 2 failed FISH testing. Notably, all of the false-positive (FISH-negative) breast cancer cases showed some degree of positivity in normal breast epithelium. ConclusionsOur findings, though descriptive, show a very strong association between NES and false-positive HER2 IHC. This confirms the need to carefully evaluate IHC-positive breast cancers for NES, and to have a low threshold for confirmatory testing by FISH.

Reduced Basal Nitric Oxide Production Induces Precancerous Mammary Lesions via ERBB2 and TGF\u03b2

One third of newly diagnosed breast cancers in the US are early-stage lesions. The etiological understanding and treatment of these lesions have become major clinical challenges. Because breast cancer risk factors are often linked to aberrant nitric oxide (NO) production, we hypothesized that abnormal NO levels might contribute to the formation of early-stage breast lesions. We recently reported that the basal level of NO in the normal breast epithelia plays crucial roles in tissue homeostasis, whereas its reduction contributes to the malignant phenotype of cancer cells. Here, we show that the basal level of NO in breast cells plummets during cancer progression due to reduction of the NO synthase cofactor, BH4, under oxidative stress. Importantly, pharmacological deprivation of NO in prepubertal to pubertal animals stiffens the extracellular matrix and induces precancerous lesions in the mammary tissues. These lesions overexpress a fibrogenic cytokine, TGFβ, and an oncogene, ERBB2, accompanied by the occurrence of senescence and stem cell-like phenotype. Consistently, normalization of NO levels in precancerous and cancerous breast cells downmodulates TGFβ and ERBB2 and ameliorates their proliferative phenotype. This study sheds new light on the etiological basis of precancerous breast lesions and their potential prevention by manipulating the basal NO level.

BRCA1 mutations attenuate super-enhancer function and chromatin looping in haploinsufficient human breast epithelial cells

BackgroundBRCA1-associated breast cancer originates from luminal progenitor cells. BRCA1 functions in multiple biological processes, including double-strand break repair, replication stress suppression, transcriptional regulation, and chromatin reorganization. While non-malignant cells carrying cancer-predisposing BRCA1 mutations exhibit increased genomic instability, it remains unclear whether BRCA1 haploinsufficiency affects transcription and chromatin dynamics in breast epithelial cells.MethodsH3K27ac-associated super-enhancers were compared in primary breast epithelial cells from BRCA1 mutation carriers (BRCA1mut/+) and non-carriers (BRCA1+/+). Non-tumorigenic MCF10A breast epithelial cells with engineered BRCA1 haploinsufficiency were used to confirm the H3K27ac changes. The impact of BRCA1 mutations on enhancer function and enhancer-promoter looping was assessed in MCF10A cells.ResultsHere, we show that primary mammary epithelial cells from women with BRCA1 mutations display significant loss of H3K27ac-associated super-enhancers. These BRCA1-dependent super-enhancers are enriched with binding motifs for the GATA family. Non-tumorigenic BRCA1mut/+ MCF10A cells recapitulate the H3K27ac loss. Attenuated histone mark and enhancer activity in these BRCA1mut/+ MCF10A cells can be partially restored with wild-type BRCA1. Furthermore, chromatin conformation analysis demonstrates impaired enhancer-promoter looping in BRCA1mut/+ MCF10A cells.ConclusionsH3K27ac-associated super-enhancer loss is a previously unappreciated functional deficiency in ostensibly normal BRCA1 mutation-carrying breast epithelium. Our findings offer new mechanistic insights into BRCA1 mutation-associated transcriptional and epigenetic abnormality in breast epithelial cells and tissue/cell lineage-specific tumorigenesis.

The effect of tamoxifen and luteinizing hormone-releasing hormone (LHRH) analogue on estrogen level in women with breast cancer

Estrogen exposure is a major risk factor for breast cancer. Increased estrogen responsiveness of breast epithelium may enhance this effect. Surgical or medical castration and antiestrogenic treatment with tamoxifen are common endocrine treatments for premenopausal women with breast cancer. However, tamoxifen therapy induces high levels of plasma estradiol, with unknown long-term effects. In this study, we investigated the effect of combining the luteinizing hormone-releasing hormone agonist with tamoxifen and measuring estradiol level . method : Are taking random samples of breast cancer patients under treatment of patients attending the Institute of Atomic Radiation in Baghdad , and specifically who use Tamoxifen ( 20 mg/day) . 100 samples and 30 sample as a control there age ( 20 – 80). Approximately 3ml of blood are collected from each women using standard procedures. And then measuring the level of estradiol E2 hormone ,Measurement of the liver enzymes ( GOT,GPT,ALP,LDH and GGT ) and billirubin for study the liver health results : combined treatment with tamoxifen and LHRH analogue cause reduced in estradiol level (37.3634±45.02893) P ≤ o.o1 which is consider the main cause of breast cancer in this study group while the control group was in normal range (93.3700±51.07188) and the level of liver enzymes and total billirubin was in normal range and there was no significant change. Conclusion : combining the luteinizing hormone-releasing hormone agonist with tamoxifen leads to reduced the level of estradiol E2 hormone while treatment tamoxifen alone cause elevating these hormone , also these drugs didn’t effected on the liver health.

SAT-339 Cross-Talk with Breast Adipose Tissue Contributes to Obesity-induced DNA Damage in BRCA Mutant Breast Epithelial Cells

Background: Obese women who carry a mutation in the DNA repair enzymes BRCA1 and/or BRCA2 are at a greater risk of developing breast cancer compared with lean BRCA1/2 mutation carriers. Causative factors that drive the increased penetrance of breast cancer in obese women are poorly characterized. Previously, we showed that BMI was positively correlated with DNA damage in breast epithelium of BRCA mutation carriers. We hypothesized that obesity-associated dysfunctional adipose tissue may cause DNA damage in neighboring breast epithelial cells. If true, this would provide evidence for the initial insults associated with increased risk of tumor formation in obese women. Methods: To test the effect of locally secreted factors on DNA damage induction, conditioned media was collected over 24 hours from primary breast adipose explants obtained from lean and obese women. Conditioned media was used to treat normal breast epithelial cells (MCF10A) harboring a heterozygous BRCA1 mutation or wildtype for BRCA. Immunofluorescence (IF) staining of the DNA damage marker ƴH2AX was carried out after treatment. Cell line findings were validated in primary breast epithelial organoids isolated by collagenase digestion of breast tissue obtained from the clinic. Additionally, RNA-seq was conducted on primary breast epithelial organoids isolated from lean and obese women to identify potential drivers of gene expression differences associated with obesity and DNA damage. Results: Conditioned media from obese breast adipose tissue stimulated DNA damage in BRCA mutant breast epithelial cells while lean conditioned media did not have this effect. Similar findings were made in primary breast epithelial organoids, suggesting a role for locally secreted factors in mediating DNA damage. Ingenuity Pathway Analysis of RNA-seq data from lean and obese primary breast organoids identified several upstream regulators of gene expression differences, including signaling by estradiol and pro-inflammatory cytokines, both of which are elevated in obese breast tissue and are known inducers of DNA damage. Conclusions: These data show for the first time that local factors produced by obese breast adipose tissue induce breast epithelial cell DNA damage. Our results suggest that therapies targeting weight or dysfunctional breast adipose tissue may reduce the increased DNA damage observed in obese BRCA mutation carriers and thereby decrease tumor formation in this high-risk population of women.

Chemical constituents of the lichen Dendriscosticta platyphylloides, Lobariaceae

Introduction: Dendriscosticta is a new genus belong the Sticta wrightii group of the family Lobariaceae. This genus of foliose lichen is widely distributed in tropical regions worldwide. The lichen Dendriscosticta platyphylloides is very abundant in Bidoup forest, Lam Dong province, Vietnam.
 Methods: The structure of these compounds was elucidated through the interpretation of their 1D and 2D-NMR and HR-MS data. The cytotoxic activities of these compounds against liver hepatocellular carcinoma (HepG2), human lung cancer (NCI-H460), human epithelial carcinoma (HeLa) and human breast cancer (MCF-7) cell lines was performed at the concentration of 100 mg/mL using the sulforhodamine B (SRB) assay.
 Results: In this paper, we reported the isolation of six known compounds, including (1) 15a-acetoxyhopan-22-ol (2) hopane-15a,22-diol, (3) zeorin, (4) cerevisterol, (5) salvigenin, and (6) 5-hydroxy-3',4',7-trimethoxyflavone.
 Conclusion: This is the first time that these compounds are isolated from Dendriscosticta genus. These compounds showed no cytotoxic activity against four cell lines.

Effect of Manganese Chloride and of Cotreatment with Cadmium Chloride on the In Vitro Proliferative, Motile and Invasive Behavior of MDA-MB231 Breast Cancer Cells.

We examined the dose–response effect of MnCl2 on the proliferative behavior of triple-negative breast cancer MDA-M231 cells vs. immortalized HB2 cells from breast epithelium taken as nontumoral counterparts. We also tested the effect of MnCl2 on tumor cell invasiveness in vitro by evaluating the relative invasion indexes through Boyden chamber assays. Moreover, we checked whether cotreatment with both MnCl2 and CdCl2 could modify the observed biological response by MDA-MB231 cells. Our results show a promotional impact of MnCl2 on cell proliferation, with 5 µM concentration inducing the more pronounced increase after 96-h exposure, which is not shared by HB2 cells. Exposure to 5 µM MnCl2 induced also an elevation of the relative invasion index of cancer cells. The Mn-mediated stimulatory effects were counteracted by cotreatment with CdCl2. These data support the concept that human exposure to high environmental concentrations of Mn may increase the risk of carcinogenesis and metastasis by prompting the expansion and dissemination of triple-negative breast cancer cells. On the other hand, the Mn-counteracting anticancer property of Cd looks promising and deserves a more detailed characterization of the involved intracellular targets aimed to the molecular modeling of specific antineoplastic agents against malignant breast cancer spreading.

Connexin 43 Loss Triggers Cell Cycle Entry and Invasion in Non-Neoplastic Breast Epithelium: A Role for Noncanonical Wnt Signaling.

(1) Background: The expression of connexin 43 (Cx43) is disrupted in breast cancer, and re-expression of this protein in human breast cancer cell lines leads to decreased proliferation and invasiveness, suggesting a tumor suppressive role. This study aims to investigate the role of Cx43 in proliferation and invasion starting from non-neoplastic breast epithelium. (2) Methods: Nontumorigenic human mammary epithelial HMT-3522 S1 cells and Cx43 shRNA-transfected counterparts were cultured under 2-dimensional (2-D) and 3-D conditions. (3) Results: Silencing Cx43 induced mislocalization of β-catenin and Scrib from apicolateral membrane domains in glandular structures or acini formed in 3-D culture, suggesting the loss of apical polarity. Cell cycle entry and proliferation were enhanced, concomitantly with c-Myc and cyclin D1 upregulation, while no detectable activation of Wnt/β-catenin signaling was observed. Motility and invasion were also triggered and were associated with altered acinar morphology and activation of ERK1/2 and Rho GTPase signaling, which acts downstream of the noncanonical Wnt pathway. The invasion of Cx43-shRNA S1 cells was observed only under permissive stiffness of the extracellular matrix (ECM). (4) Conclusion: Our results suggest that Cx43 controls proliferation and invasion in the normal mammary epithelium in part by regulating noncanonical Wnt signaling.

Heterobimetallic PtII‐AuI Complexes Comprising Unsymmetrical 1,1‐Bis(diphenylphosphanyl)methane Bridges: Synthesis, Photophysical, and Cytotoxic Studies

In the present work, a series of aryl‐cycloplatinated(II) complexes with general formula [Pt(C^N)(Ar)(κ1‐dppm)], 1, [C^N = 7,8‐benzoquinolinyl (bzq) or 2‐phenylpyridinyl (ppy); Ar = C6F5 or p‐MeC6H4, dppm = 1,1‐bis(diphenylphosphanyl)methane] was employed in the reaction with AuCl(SMe2) in order to generate heterobimetallic PtII‐AuI complexes, [Pt(C^N)(Ar)(µ‐dppm)Au(Cl)], 2, featuring a dppm bridge between the metal centers. The expectation was to induce metallophilic character into the excited state and to reduce non‐radiative deactivation pathways of the dangling auxiliary κ1‐dppm ligand through molecular motions, to improve the photophysical properties. After characterization of the new complexes by means of NMR spectroscopy and X‐ray crystallography technique, the photophysical properties of all the complexes were investigated by UV/Vis and photoluminescence spectroscopy. Both of the monometallic complexes and heterobimetallic products have shown to be luminescent in different states and temperature conditions. However, by addition of AuI, the impact on the photophysics of the heterobimetallic products in relation to the precursors with dangling dppm is minimal, a finding which can be attributed to the absence of a PtII‐AuI bond in these compounds. Indeed, the character of the excited states of the monomer PtII complexes and their corresponding bimetallic PtII‐AuI ones are similar, as confirmed by density functional theory (DFT) and time resolved DFT (TD‐DFT) calculations. The cytotoxic activities of the compounds along with that of [ClAu(µ‐dppm)AuCl] were evaluated against human breast cancer (MCF‐7), human lung cancer (A549), human ovarian cancer (SKOV3) and non‐tumorigenic epithelial breast (MCF‐10A) cell lines. The highest activity was found for the heterometallic Pt‐Au species, suggesting a cooperative effect of both metallic fragments. The most cytotoxic compound, i.e. [Pt(bzq)(p‐MeC6H4)(µ‐dppm)Au(Cl)], 2b, effectively causes cell death in MCF‐7 cancer cell line by inducing apoptosis. Fluorescence microscopy experiments for 2a were performed.

Tyrosine Phosphorylation of p27Kip1 Correlates with Palbociclib Responsiveness in Breast Cancer Tumor Cells Grown in Explant Culture.

Cdk4-targeting drugs, such as palbociclib, are approved for metastatic ER/PR+, Her2- breast cancer. However, other than loss of retinoblastoma, which is very rare in this subset, there are no biomarkers to predict response. Cyclin D or cdk4 levels are not by themselves indicative, because p27Kip1 is required for cyclin D-cdk4 complex activation. Tyrosine phosphorylation of p27, including modification on residue Y88 (pY88), activates DK4-p27, and the pY88 level correlates with palbociclib responsiveness in cell lines. We developed dual IHC staining for p27 and pY88, and found that benign breast epithelium was negative, while breast cancer biopsies (of varied hormonal status) could be stratified for pY88 status. Lack of pY88 suggested that DK4 was inactive, and that these samples would not have the target required for palbociclib response. Tumor resection material was grown in explant culture, treated with palbociclib, and stained with Ki67 as a marker of response. Explants from the no pY88 group were nonresponsive, while explants from the low or high pY88 group responded to drug. IMPLICATIONS: Use of the pY88 biomarker, as a surrogate for cdk4 activity, may identify patients responsive to cdk4-targeting drugs and expand use of this therapy.Visual Overview: http://mcr.aacrjournals.org/content/molcanres/17/3/669/F1.large.jpg.

FUN14 domain-containing 1 promotes breast cancer proliferation and migration by activating calcium-NFATC1-BMI1 axis

BackgroundFUN14 domain-containing 1 (FUNDC1), as a novel member of mitochondria-associated endoplasmic reticulum (ER) membranes associates with mitochondrial division and mitophagy. However, the expression profile and functional roles of FUNDC1 remain largely unclear in human cancer biology, including breast cancer (BC).MethodsImmunohistochemistry and western blot analysis were used to determine the expression of FUNDC1 and BMI1 polycomb ring finger oncogene (BMI1). CCK8, cell counting and transwell assays were used to analyze cell proliferation, migration and invasion, respectively. Luciferase reporter and chromatin immunoprecipitation (ChIP) assays were used to detect the transcriptional regulation of Nuclear factor of activated T-cells, cytoplasmic 1 (NFATC1). The prognostic merit of NFATC1 expression was assessed by Kaplan-Meier assay.FindingsImmunohistochemistry revealed strong immunostaining for FUNDC1 in cytoplasmic and nuclear membrane distribution in BC tissues as compared with normal breast epithelium. Kaplan–Meier survival analysis showed worse outcome for BC patients with high FUNDC1 expression. In vitro assay of gain- and loss-of-function of FUNDC1 suggested that FUNDC1 could stimulate BC cell proliferation, migration and invasion. Furthermore, elevated FUNDC1 level promoted Ca2+ cytosol influx from ER and extracellular, as well as NFATC1 nuclear translocation and activity. Nuclear NFATC1 bound to the BMI1 gene promoter and transcriptionally upregulated its expression. Notably, BMI1 overexpression could rescue the loss of function of FUNDC1. Co-expression of FUNDC1 and BMI1 in BC patients predicted worse prognosis than without either expression.InterpretationFUNDC1 might promote BC progression by activating the Ca2+–NFATC1–BMI1 axis. This pathway may be promising for developing multiple targets for BC therapy.

Abstract P5-08-05: The interplay between stromal density, epithelial mesenchymal transition and chemoresistance in breast cancer

Abstract Epithelial Mesenchymal Transition (EMT) refers to the transition of cells from a more differentiated epithelial phenotype to a less differentiated mesenchymal phenotype, a process that may be triggered by a range of therapeutic interventions including cytotoxic treatment, and which we have previously linked to poor breast cancer (BrCa) outcome after neoadjuvant chemotherapy (NAC)1. Mammographic breast density (MBD)represents the white radiographic appearance of epithelial and stromal breast tissue on a mammogram. High MBD in patients being treated for BrCa also associates with chemoresistance, correlating with lower pathological complete response rates (pCR)2. Linking these two stimuli, EMT can also be induced by artificial high-density stroma, where it also leads to chemoresistance in vitro3. Here we set out to validate the link between poor outcome after NAC and EMT in a larger validatory patient cohort, and to ascertain the molecular drivers through which EMT is triggered in this setting. Further we look to confirm the association of high MBD with poor chemoresponse in the same cohort, and to assess whether this chemoresistance is mediated through EMT with the same drivers. In a pilot cohort of 50 NAC-treated locally advanced BrCas with a pCR rate of 20%, pre-NAC biopsies and post-NAC surgical specimens were analysed for expression changes in a panel of EMT-related markers across treatment using 230 Nanostring assays. This included the EMT-driving transcription factors TWIST 1 and 2, SNAIL 1, 2 and 3 and ZEB 1 and 2, which were correlated with risk of relapse. Snail-3 showed significantly greater induction in relapsers compared to non-relapsers (OR=1.8, p=0.04) with a borderline significantly greater induction of TWIST-1 (OR=2.4, p=0.08) in relapsers in addition. In a subsequent 240-patient validation cohort with a pCR rate of 18%, contralateral cranio-caudal view mammograms from the time of diagnosis have been collated and digitized with MBD assessment employing Cumulus software ongoing. Percent breast density will be assessed both as a continuous variable and by quartiles. Immunohistochemistry on pre- and post-operative tissue sections with pan-cytokeratin-vimentin co-staining to identify EMT and staining for SNAIL-3 and TWIST-1 is also in progress. Associations between MBD, EMT before and after chemotherapy, pCR and relapse-free survival will be presented. The role of Snail-3 and TWIST-1 in the interplay between MBD, EMT and outcome is being explored and will be reported. Citation Format: Agarwal V, Spalding LJ, Blick T, Dobrovic A, Thompson EW, Redfern A. The interplay between stromal density, epithelial mesenchymal transition and chemoresistance in breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-08-05.

Abstract P2-14-02: Get skin sparing mastectomy right: Reduce local recurrence rate by meticulous removal all breast tissue

Abstract Background: Skin sparing mastectomy (SSM) was introduced to allow aesthetically better results when combined with breast reconstruction. However, preservation of a larger skin envelope than that left after standard mastectomy could lead to retention of significant amounts of residual breast tissue in the subcutaneous fat, increasing the risk of local recurrence or new breast cancers developing. Study method: Over a 15 year period, subcutaneous fat samples were routinely sampled during SSM and reconstruction performed by one surgeon. SSM was offered to all patients bar those with inflammatory cancers unresponsive to primary chemotherapy and those medically unfit for surgery. Hospital and personal databases of these cases were interrogated for: presence of breast epithelial tissue in subcutaneous fat samples local recurrence systemic recurrence aesthetic grade by independent surgeons Results: 402 SSM were reviewed. Results of subcutaneous samples were recorded for 357. 3 patients had residual breast tissue in subcutaneous fat samples (0.75%), 4 developed a local recurrence (1%), 42 systemic recurrence (11%). 238 patients had G1-3 invasive ductal carcinoma, size range 3-100mm, 25 invasive lobular carcinoma, 12.5-88mm and 87 DCIS, 20-116mm. These included patients who responded to preoperative chemotherapy and hormone therapy. 52 patients had prophylactic procedures. The aesthetic outcome was judged as good for 76%, moderate for 20%. The median follow up period was 9 years, giving annual local and systemic recurrence rates of 0.11% and 1.16% respectively. Conclusions: There was a low incidence of residual breast tissue in random subcutaneous fat samples collected during SSM (0.75%) The local recurrence rate was one tenth of the systemic recurrence rate, 1% vs 11%, and annual rates of 0.11% and 1.16% respectively. Discussion: Surgery for breast cancer is a local treatment, and though removal of the main tumor will contribute to systemic control, that will be achieved by a combination of local and systemic therapies based on the biology of the individual's disease. Once surgery is performed, it can have no further influence on systemic control. However, the meticulousness of the surgical procedure can influence subsequent local control. Residual breast tissue left after mastectomy may harbor areas of disease that may not respond to other adjuvant therapies leading to local recurrence, or separate new cancers. Traditionally it has been considered that some breast tissue will be retained in skin flaps post mastectomy, up to 5% with standard mastectomies. This study suggests that this can be avoided, even when a large skin envelope is retained for an aesthetic outcome, and lead to a marked reduction in local recurrence. Citation Format: Drabble EH. Get skin sparing mastectomy right: Reduce local recurrence rate by meticulous removal all breast tissue [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-14-02.

Abstract P3-05-03: Identification of epigenetically silenced breast cancer driver genes

Abstract Breast cancer is clinically and molecularly complex disease driven by aberrant genetic and epigenetic alterations. Epigenetic alterations in particular DNA methylation changes are one of the most important events involved in breast cancer initiation and progression. Previous reports identified many aberrant DNA methylation signatures associated with molecular subtypes of breast cancer and over 100 candidate genes with promoter hypermethylation in breast cancer. However, it remains elusive which of these genes with promoter hypermethylation play “driver” role in tumorigenesis. In previous studies, the average gain of DNA methylation across all cancer samples compared to the average DNA methylation in normal samples has been the criterion to select for potential targets. However, known tumor suppressor driver genes regulated by methylation are relatively infrequently altered in target cancers. Therefore, we propose the paradoxical hypothesis that identifying hypermethylated cancer drivers require focusing on infrequent rather than frequent events. Hence, to identify these potential driver genes, we developed an algorithm with two unique properties. First, unlike previous studies we focused on targets that gained DNA methylation relatively infrequently (10-40%) and that lost expression in breast cancer. Second, using this algorithm, we distinguished cancer dependent gain of DNA methylation from age-dependent gain of methylation. To discern age dependent and independent DNA methylation changes, we generated DNA methylation sequencing data on 29 normal purified breast epithelium (age range 33-82 years old). Furthermore, to study the biological effects of the overexpression or downregulation of these genes, we generated DNA methylation sequencing data on 6 breast cancer cell lines. We also used DNA methylation and RNA expression datasets (675 cancer, 100 normal) available through the TCGA. Using our algorithm, we identified 53 genes with age independent promoter hypermethylation and loss of expression in TCGA tumor samples. To begin testing the biological effects of these driver genes, we performed canonical pathway enrichment analyses using Ingenuity Pathway Analysis software. We also investigated the mutational status of these genes and their molecular subtype enrichment. Based on these analyses, we picked 12 genes (C10orf125, RUNX3, YOD1, FXYD5, SMOC1, SLC16A5, RNLS, DKK1, PNPLA3, FZD10, RND2, and PLCB1) for further study. We stably overexpressed these potential driver genes in different breast cancer cell lines. Twelve genes out of the 12 tested, slowed cell proliferation and 9 decreased anchorage independent growth. We further validated these driver genes by knocking them out in normal human mammary epithelial cells using CRISPR/Cas9 tool. The loss of these genes, increased cell proliferation rate in normal human mammary epithelial cells compared to the control cells. In conclusion, based on our preliminary data, using bioinformatics tools as well as functional assays, we identified epigenetically altered breast cancer driver genes. Identifying and deciphering true epigenetic cancer drivers could potentially lead to the development of therapeutic drugs targeting these genes and/or targeting pathway dependence. Citation Format: Panjarian S, Madzo J, Slater C, Jelinek J, Chen X, Issa J-P. Identification of epigenetically silenced breast cancer driver genes [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-05-03.

Abstract A081: Tumors expressing ACKR1 exhibit a unique signature of tumor-infiltrating immune cells in women with breast cancer

Abstract Tumor-associated immune cells, stroma and several other cell types make up the complex tumor microenvironment (TME) that contributes to a broad spectrum of potential clinical outcomes for breast cancer (BC) patients. Part of this delicate interplay is the interaction between pro-inflammatory chemokines and their receptors, which direct the migration of immune cells to areas of tumor-associated inflammation. Our focus in this complex process is on the role of the Atypical Chemokine Receptor 1 (ACKR1/DARC). In general immune response, its expression on erythrocytes helps to maintain chemokine homeostasis by sequestering chemokines in circulation while its expression on endothelial tissue transcytoses the chemokines from tissue into circulation, which ultimately affects which immune cells are brought to the TME. Its role in epithelial tissue expression is less understood. The purpose of this study is to investigate differential gene expression of ACKR1 in breast epithelial tumor tissue through IHC methods, and to determine how that expression correlates with both circulating and infiltrating proinflammatory chemokines. In addition, we will show this role to be associated with specific classes of tumor-infiltrating lymphocytes (TIL) in BC. Circulating chemokine levels for a variety of ACKR1-associated proinflammatory chemokines were determined using Luminex multiplexing assays. Results from our study cohort indicate differential expression of ACKR1 on epithelial tumor tissue, which correlated with a unique signature of immune cell infiltrates and associated proinflammatory chemokines. Tumors positive for AKCR1 expressed higher levels of circulating and infiltrating CCL2 (MCP-1) and lower levels of CXCL8 (IL-8). Tumor-expressing ACKR1 was also found to be associated with T-cells, B-cells, macrophages, and monocytes, where positive tumors tended to express a more robust profile of TILs. Our preliminary data suggest the presence or absence of ACKR1 on breast epithelial tumor tissue can influence the chemokine and immune cell profile within the TME, which can ultimately influence tumor aggressiveness, proliferation, and response to treatments, such as immunotherapies. Citation Format: Brittany D. Jenkins, Talina Fleifel, Rachel Martini, Haythem Ali, Lisa Newman, Melissa Davis. Tumors expressing ACKR1 exhibit a unique signature of tumor-infiltrating immune cells in women with breast cancer [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A081.

The relationship between terminal duct lobular unit features and mammographic density among Chinese breast cancer patients.

Extensive mammographic density (MD), a well-established breast cancer risk factor, is a radiological representation of stromal and epithelial breast tissue content. In studies conducted predominantly among Caucasian women, histologic measures of reduced terminal duct lobular unit (TDLU) involution have been correlated with extensive MD, but independently associated with breast cancer risk. We therefore examined associations between TDLU measures and MD among Chinese women, a low-risk population but with high prevalence of dense breasts. Diagnostic pre-treatment digital mammograms were obtained from 144 breast cancer cases at a tertiary hospital in Beijing and scored using the Breast Imaging Reporting and Data System (BI-RADS) density classification. TDLU features were assessed using three standardized measures (count/100 mm2 , span [μm], and acini count/TDLU) in benign tissues. Associations between each of TDLU measures and MD were examined using generalized linear models for TDLU count and span and polytomous logistic regression for acini count with adjustment for potential confounders stratified by age. Among women ≥50 years, 63% had dense breasts; cases with dense breasts (BI-RADS, c-d) had greater TDLU count (21.1 [SE = 2.70] vs. 9.0 [SE = 1.83]; p = 0.0004), longer span (480.6 μm [SE = 24.6] vs. 393.8 μm [SE = 31.8]; p = 0.03), and greater acini count (ORtrend = 16.1; 95%CI = 4.08-63.1; ptrend < 0.0001) compared to those with non-dense breasts (BI-RADS, a-b). Among women <50 years, 91% had dense breasts, precluding our ability to detect associations. Our findings are consistent with previously reported associations between extensive MD and reduced TDLU involution, supporting the hypothesis that breast cancer risk associated with extensive MD may be related to the amount of "at-risk" epithelium.