Breast Adipose Research Articles

The Importance of Breast Adipose Tissue in Breast Cancer.

Adipose tissue is a complex endocrine organ, with a role in obesity and cancer. Adipose tissue is generally linked to excessive body fat, and it is well known that the female breast is rich in adipose tissue. Hence, one can wonder: what is the role of adipose tissue in the breast and why is it required? Adipose tissue as an organ consists of adipocytes, an extracellular matrix (ECM) and immune cells, with a significant role in the dynamics of breast changes throughout the life span of a female breast from puberty, pregnancy, lactation and involution. In this review, we will discuss the importance of breast adipose tissue in breast development and its involvement in breast changes happening during pregnancy, lactation and involution. We will focus on understanding the biology of breast adipose tissue, with an overview on its involvement in the various steps of breast cancer development and progression. The interaction between the breast adipose tissue surrounding cancer cells and vice-versa modifies the tumor microenvironment in favor of cancer. Understanding this mutual interaction and the role of breast adipose tissue in the tumor microenvironment could potentially raise the possibility of overcoming breast adipose tissue mediated resistance to therapies and finding novel candidates to target breast cancer.

The Influence Of Physical Activity And Body Composition On Gene Expression In Breast Adipose Tissue

Higher physical activity levels and healthy body weights are associated with a lower risk of postmenopausal breast cancer. Little is known about the biological mechanisms underlying this association, but the microenvironment created in the breast tissue is of interest. Adipose tissue is recognized as an endocrine organ, responding to the local and systemic environment. PURPOSE: To explore the association between self-reported lifestyles factors, and breast adipose tissue and the microenvironment it creates. METHODS: Using a cross-sectional design, women undergoing reduction mammoplasty surgery were recruited. Participants completed standard questionnaires about their usual physical activity, weight history, reproductive history, and past-year dietary intake. Body weight was abstracted from medical records. A sample of breast tissue was collected during surgery. An adipose-rich section was isolated under sterile conditions. Part of the sample was formalin fixed (sectioned at 7 μm thickness for measurement of mean adipocyte size with Image J) and part was flash frozen for RNA isolation. Associations between mean adipocyte size and lifestyle variables were examined by multivariate analysis to determine associations between genes and lifestyle variables. RESULTS: Of 72 women recruited, RNA was isolated from 65 samples. Participants were a mean age of 43 years (range 19-70) and had a mean body mass index of 27.0 kg/m2 (SD 5.0). BMI was positively associated with adipocyte size (β = 0.06, p<0.01) and transportation physical activity was negatively associated with adipocyte size (β = -0.25, p=0.02). Six genes, namely SLC27A2, TTC36, WHSC1L1, AASS, MOCS1, GLYCTK, were found to be associated with adipocyte size. CONCLUSION: Adipose tissue biology is associated with lifestyle exposures in normal breast tissue. Our findings provide directions for future research into the impact of lifestyle on the microenvironment of healthy breast tissue.

Novel Body Composition Predictors of Outcome in Patients With Angiosarcoma of the Breast: A Preliminary Study.

The aim of the study was to determine abdominal and breast adipose tissue parameters on 18-fluorodeoxyglucose positron emission tomography/computed tomography (CT) that may serve as outcome predictors in breast angiosarcoma patients. Women with breast angiosarcoma (n = 13) who underwent 18-fluorodeoxyglucose positron emission tomography/CT were identified. A control group was selected (n = 25). Abdominal subcutaneous (SAT) and visceral adipose tissue (VAT) were assessed on unenhanced computed tomographies. Breast adipose tissue (BAT) volumes of the uninvolved breast were quantified. Metabolic activity of VAT, SAT, and BAT was calculated (standardized uptake value [SUV]). Breast angiosarcoma patients had higher metabolic activity of VAT compared with controls (SUV 0.93 ± 0.39 vs 0.64 ± 0.11, P = 0.044). Within the patient group, there were 6 deaths (46.2%). Patients who died had higher SAT activity (SUV 0.52 ± 0.24 vs 0.29 ± 0.06, P = 0.027) and higher BAT metabolic activity (SUV 0.48 ± 0.20 vs 0.27 ± 0.11, P = 0.045) compared with nondeceased patients. Patients with breast angiosarcoma have higher metabolic activity of VAT. Higher abdominal SAT and higher BAT metabolic activity of the uninvolved breast might predict mortality.

Transfer of dechlorane plus between human breast milk and adipose tissue and comparison with legacy lipophilic compounds

In this study, levels of dechlorane plus (DP) in breast milk and matched adipose tissue samples were measured from 54 women living in Wenling, China. Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured simultaneously for comparison. The levels of ∑DPs/∑PBDEs varied from less than one to several dozens of ng g−1 lipid weight (lw) in matrices and the levels of ∑PCBs varied between several to hundreds of ng g−1 lw. In the same matrix, ∑DPs and ∑PCBs/∑PBDEs showed a significant relationship (p < 0.05), indicating that they shared common sources. Accordingly, there was a strong association of lipid-adjusted concentrations of individual compounds (BDE-209 excluded) between matrices (p < 0.001), suggesting that breast milk could be a proxy for adipose tissue in human bioburden monitoring of these compounds. The predicted lipid-adjusted milk/adipose ratios varied from 0.62 to 1.5 but showed significant differences (p<0.001) between compounds, suggesting a compound-specific transfer between milk lipids and adipose tissue lipids. Specifically, the milk/adipose ratios for syn-DP and anti-DP (−1.40 and 1.3, respectively) were significantly higher than those of CB congeners and hexa/hepta-BDE congeners (p < 0.05). In addition, unlike PCBs/PBDEs (excluding BDE-209), DP’s hydrophobicity might not be responsible for its preferable distribution in milk lipids. Instead, the interaction with nonlipid factors played a key role. The fraction of anti-DP between the two kinds of matrices was not significantly different, suggesting that the biochemical transfer processes may not be efficient enough to distinguish DP isomers. Nevertheless, the congener patterns of PCBs/PBDEs gave a clue about the compound-specific transfer between milk and adipose tissue. To our knowledge, this is the first to report the relationships of DP between adipose tissue and breast milk. These results could provide useful and in-depth information on biomonitoring of DP and facilitate the understanding of the accumulation and excretion potentials of DP and its distribution-related mechanism in humans.

Influence of breast cancer risk factors and intramammary biotransformation on estrogen homeostasis in the human breast

Understanding intramammary estrogen homeostasis constitutes the basis of understanding the role of lifestyle factors in breast cancer etiology. Thus, the aim of the present study was to identify variables influencing levels of the estrogens present in normal breast glandular and adipose tissues (GLT and ADT, i.e., 17β-estradiol, estrone, estrone-3-sulfate, and 2-methoxy-estrone) by multiple linear regression models. Explanatory variables (exVARs) considered were (a) levels of metabolic precursors as well as levels of transcripts encoding proteins involved in estrogen (biotrans)formation, (b) data on breast cancer risk factors (i.e., body mass index, BMI, intake of estrogen-active drugs, and smoking) collected by questionnaire, and (c) tissue characteristics (i.e., mass percentage of oil, oil%, and lobule type of the GLT). Levels of estrogens in GLT and ADT were influenced by both extramammary production (menopausal status, intake of estrogen-active drugs, and BMI) thus showing that variables known to affect levels of circulating estrogens influence estrogen levels in breast tissues as well for the first time. Moreover, intratissue (biotrans)formation (by aromatase, hydroxysteroid-17beta-dehydrogenase 2, and beta-glucuronidase) influenced intratissue estrogen levels, as well. Distinct differences were observed between the exVARs exhibiting significant influence on (a) levels of specific estrogens and (b) the same dependent variables in GLT and ADT. Since oil% and lobule type of GLT influenced levels of some estrogens, these variables may be included in tissue characterization to prevent sample bias. In conclusion, evidence for the intracrine activity of the human breast supports biotransformation-based strategies for breast cancer prevention. The susceptibility of estrogen homeostasis to systemic and tissue-specific modulation renders both beneficial and adverse effects of further variables associated with lifestyle and the environment possible.

Detection of crown-like structures in breast adipose tissue and clinical outcomes among African-American and White women with breast cancer

BackgroundCrown-like structures in breast adipose tissue (CLS-B), composed of necrotic adipocytes encircled by macrophages, are associated with obesity and hypothesized to worsen breast cancer prognosis; however, data are sparse, particularly in multi-racial populations.MethodsWe assessed specimens for CLS-B from 174 African-American and 168 White women with stage I–III breast cancer treated by mastectomy. Benign breast tissue from an uninvolved quadrant was immunohistochemically stained for CD68 to determine CLS-B presence and density (per cm2 of adipose tissue). Demographic and lifestyle factors, collected via medical record review, were analyzed for associations with CLS-B using logistic regression. Multivariable Cox proportional hazards models were used to compute hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between CLS-B and overall (OS) or progression-free (PFS) survival.ResultsDetection of any CLS-B was similar between African-American (32%) and White (29%) patients with no evidence of an association between race and CLS-B in multivariable models (OR = 0.82, 95% CI = 0.49–1.36). Detection of CLS-B was associated with obesity (OR = 4.73, 95% CI = 2.48–9.01) and age ≥ 60 years at diagnosis (OR = 1.78, 95% CI = 0.99–3.21). There was some evidence of associations with parity and current smoking status. Detection of CLS-B was not associated with OS (HR = 1.02, 95% CI = 0.55–1.87) or PFS (HR = 0.99, 95% CI = 0.59–1.67).ConclusionsOur results show a strong, positive association between BMI and CLS-B in non-tumor tissue similar to previous findings. Detection of CLS-B did not vary by race and was not associated with worse OS or PFS.

Comparison of sonoelastographic values of breast tissue with mammographically and ultrasonically assessed density: a cross-sectional study

AimTo determine the relationship between breast stiffness assessed with sonoelastography (elasticity) and breast tissue density assessed with mammography (MG) and ultrasound (US).MethodsThis cross-sectional study involved 100 women who underwent MG, gray-scale US, and shear-wave sonoelastography during 2013. Mammographic density was categorized into four groups and sonographic density into three groups according to Breast Imaging-Reporting and Data System criteria. The stiffness of breast parenchymal and adipose tissue in all breast quadrants was quantified by shear-wave sonoelastography. Mean elastographic estimates were compared with MG- and US-derived density estimates.ResultsParenchymal and adipose tissue elasticity positively correlated with MG- and US-derived breast density (for parenchyma: for MG Kendall’s tau_b 0.522; Jonckheere-Terpstra test P < 0.001 and for US Kendall’s tau_b 0.533; Jonckheere-Terpstra test P < 0.001); the higher was the breast density on MG and US, the higher was the elastographic stiffness.ConclusionSonoelastographic breast stiffness strongly positively correlated with breast density. Thus, sonoelastography may have a potential for estimating the breast cancer risk, which allows a novel application of this technique in routine clinical practice.

Abstract C074: Presence of crown-like structures in breast adipose tissue and clinical outcomes among African-American and White breast cancer patients

Abstract Background: Crown-like structures in breast adipose tissue (CLS-B), indicative of proinflammatory conditions, are most frequently observed among obese (body mass index, BMI ≥30 kg/m2) women and may contribute to poor prognosis in this group. African-American (AA) women have disproportionately higher rates of obesity than White women, and at least one prior study suggests the prevalence of CLS-B may be higher among AA women. However, most previous studies have examined CLS-B within affected tissues, which may reflect inflammation in the tumor microenvironment, and few have examined the association between CLS-B and clinical outcomes by race. Methods: We examined the presence of CLS-B detected by CD68 immunohistochemistry in normal adjacent breast tissue from a quadrant uninvolved by tumor obtained via mastectomy among 174 African-American women and 168 White women with stage I—III breast cancer diagnosed at Emory University Hospitals (2007—2012). We also investigated associations between CLS-B and other demographic and lifestyle factors at diagnosis (e.g., BMI, smoking status, age at menarche, parity, lactation, menopausal status, hormone replacement therapy use, and family history of breast cancer). Patients were followed for an average of seven years after diagnosis for recurrence and survival. Multivariable Cox proportional hazards models were used to compute hazard ratios (HR) and 95% confidence intervals (CI) for associations between CLS-B presence and progression-free survival (PFS), controlling for BMI and other potential confounders. Results: Median age at diagnosis for both AA and White women was 54 years, with more than 60% postmenopausal among both groups. AA women were more likely than White women to be obese (52% vs. 24%) and have ER- tumors (30% vs. 12%). Presence of any CLS-B was similar between AA (32%) and White (29%) patients. In multivariable models, we did not find any association between CLS-B and race (HR=1.14, 95% CI: 0.72, 1.82) with the only statistically significant factors being BMI (≥30 vs. 18.5-&amp;lt;25 kg/m2: HR=4.36, 95% CI: 2.17, 8.76) and parity (1+ vs. 0 births: HR=0.43, 95% CI: 0.21, 0.91). Over follow-up, 46 breast cancer recurrences and 52 deaths (23 from breast cancer) occurred. Overall, the presence of CLS-B was not associated with PFS (multivariable HR: 0.97, 95% CI: 0.58, 1.62). When examined by race, there was a difference in the direction of the association between CLS-B and PFS among AA women (HR=1.25, 95% CI: 0.64, 2.46) compared to White women (HR=0.75, 95% CI: 0.33, 1.71), although this difference was not statistically significant (P=0.86). Conclusion: Our results show a strong, positive association between BMI and CLS-B in non-tumor tissue and an inverse association with parity. We did not observe a difference in CLS-B presence by race nor did we find CLS-B to be associated with worse progression-free survival, which is in contrast to previous studies that have examined the presence of CLS-B within specimens in close proximity to the tumor. Citation Format: Aswathy M Cheriyan, Mark E Sherman, Yuan Liu, Keerthi Gogineni, Jiaqi Liu, Jiabei He, Uma Krishnamurti, Ryan Ashiqueali, Jinjing He, Rami Yacoub, Jasmine Miller-Kleinhenz, Lauren E McCullough, Maret L Maliniak. Presence of crown-like structures in breast adipose tissue and clinical outcomes among African-American and White breast cancer patients [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr C074.

SUN-126 Distinct Molecular Phenotypes of Non-Diseased Breast Adipose Tissue of Pre-Menopausal Obese and Non-Obese Women May Underlie Differing Breast Cancer Risks

Obesity is a major risk factor for many chronic diseases including postmenopausal breast cancer. Paradoxically, breast cancer susceptibility is inversely linked to obesity in pre-menopausal women. Adipose tissues are active endocrine organs that play major roles in tumor development and progression; however, fat depots at different anatomical sites are biologically and functionally distinct and their singular influence on breast epithelial biology remains unclear. To study the early events by which breast adiposity may provide a microenvironment predisposing normal breast epithelial cells to tumorigenesis, we collected breast tissue from pre-menopausal (n=10/group) non-obese (NO, BMI=27.6±0.8) and obese (O, BMI=44.5±2.8) women of comparable ages (NO: 36.1± 3.3; O: 40.0±2.0) with no breast cancer and undergoing elective breast reduction surgery. Breast adipose tissue and corresponding glandular cells were analyzed histologically and evaluated for expression of genes (adipokines, cytokines, steroid hormone signaling) by QPCR and proteins (proliferation, apoptosis, inflammation) by IHC. Adipocyte size distributions from NO and O breasts did not differ (P=0.9). However, adipose mRNA levels for pro-inflammatory cytokines (IL-6, IL-8, CSF-1, MCP-1) and adipokines (LEP, CFD) were higher for O than NO (P<0.05). AdipoQ, ER-α, and ER-β transcript levels were lower for O than NO (P<0.05), while those for CYP19 and PTGS2 showed reverse trends (O>NO, P<0.05). In the corresponding glandular cells, NO had higher mRNA levels for IL-6, IL-8, ER-α, and ER-β than O (P<0.05). Immunostaining with anti-Ki67 antibodies indicated that O glandular cells were 3-fold less proliferative than those for NO, consistent with their lower Cyclin D1 mRNA levels (P<0.05). Galectin-1, a pro-fibrotic protein, showed predominant myo- vs. luminal epithelial localization, with staining intensities for O tending to be higher (P=0.07) than for NO. Perilipin immunostaining was specific for adipocytes and did not differ for O and NO. A non-targeted approach using a Human Cytokine Array (R&D Systems) was employed to further evaluate the inflammation status of O vs. NO adipose. The analyses confirmed the higher expression of IL-8, Leptin and CFD (by QPCR) in O vs. NO and identified C-reactive protein, EMMPRIN, Trefoil Factor-3, Cystatin-3 and Macrophage Migration Inhibitory Factor-1 as greater in O than NO (~2-fold). Our findings demonstrate marked differences in gene and protein expression patterns of O and NO breast adipose tissue, which were accompanied by a suppression of proliferation of O relative to NO breast epithelium. We speculate that early exposure of the breast epithelium to a highly inflammatory environment fueled by breast adiposity may promote a senescent state that confers protection from pre-menopausal breast cancer.

SAT-126 Breast Adipose Tissue Extracellular Vesicles from Obese Women Increase Breast Cancer Aggressiveness - a Novel Mechanism for the Obesity-Breast Cancer Link

Background and Objectives: Breast cancer is among the most common cancer in women with 2.1 million new cases detected each year. Numerous studies have demonstrated a connection between body mass index (BMI) and cancer incidence, with obesity (BMI ≥ 30) being responsible for the development of at least 13 types of cancer, and 15% to 20% of total cancer-related mortality. The effects of extracellular vesicles (EVs) derived from the obese adipose tissue microenvironment on breast cancer have not yet been clearly elucidated. Methods: EVs were obtained from media conditioned with human breast adipose tissue from reduction mammoplasty (n=31). Women were healthy at the time of surgery and had no history of breast cancer. Patient samples were stratified based on their body mass index (BMI), with a BMI < 25 considered healthy and a BMI ≥ 25 considered overweight/obese. Breast adipose tissue-derived EVs (AT-EVs) were characterized (Quantitative Mass Spectrometry) and used to treat human breast cancer cell lines, including the ER+ MCF7 and triple negative breast cancer (TNBC) MDA-MB-231. Effects on cell proliferation and migration in vitro, and on tumor growth in a mouse xenograft model, were examined after long-term education with EVs. RNA sequencing was performed to investigate potential reprogramming induced by AT-EVs. Results: We found a positive correlation between protein amount per AT-EV and BMI. Quantitative proteomics of AT-EVs revealed 46 proteins that were significantly higher and 54 proteins that were significantly lower in specimens from women with a BMI ≥ 25 compared to women with a BMI < 25. AT-EVs from patients with a BMI ≥ 25 induced proliferation of MCF7 cells compared to AT-EVs from patients with a BMI < 25. Obese EVs induced a more aggressive phenotype in MDA-MB-231 cells, increasing their invasiveness in vitro. Obese EVs also increased the growth of MCF7 and MDA-MB-231 cells in vivo. Ingenuity pathway analysis of RNA-Seq data identified significant differences in mTOR signaling and canonical pathways associated with altered mitochondrial function. Conclusion: Our studies identify a novel mechanism to explain the obesity-breast cancer link in older women. Namely, that in obesity, the breast microenvironment produces EVs capable of reprogramming breast cancer cells to grow faster and be more aggressive. Identifying which cargo in breast AT-EV mediates these effects may provide new targets for intervention.

Obesity-associated Adipose Stromal Cells Promote Breast Cancer Invasion Through Direct Cell Contact and ECM Remodeling.

Obesity increases the risk and worsens the prognosis for breast cancer due, in part, to altered adipose stromal cell (ASC) behavior. Whether ASCs from obese individuals increase migration of breast cancer cells relative to their lean counterparts, however, remains unclear. To test this connection, multicellular spheroids composed of MCF10A-derived tumor cell lines of varying malignant potential and lean or obese ASCs were embedded into collagen scaffolds mimicking the elastic moduli of interstitial breast adipose tissue. Confocal image analysis suggests that tumor cells alone migrate insignificantly under these conditions. However, direct cell-cell contact with either lean or obese ASCs enables them to migrate collectively, whereby obese ASCs activate tumor cell migration more effectively than their lean counterparts. Time-resolved optical coherence tomography (OCT) imaging suggests that obese ASCs facilitate tumor cell migration by mediating contraction of local collagen fibers. Matrix metalloproteinase (MMP)-dependent proteolytic activity significantly contributes to ASC-mediated tumor cell invasion and collagen deformation. However, ASC contractility is also important, as co-inhibition of both MMPs and contractility is necessary to completely abrogate ASC-mediated tumor cell migration. These findings imply that obesity-mediated changes of ASC phenotype may impact tumor cell migration and invasion with potential implications for breast cancer malignancy in obese patients.

Adipocyte PD-L1 suppresses anti-tumor immune response and promotes breast cancer progression

Abstract PD-L1 has become a major target in anti-cancer immunotherapy, however the overall response rate still remains relatively low among most types of cancers, notably breast cancer. There is an unmet need to boost efficacy of immune checkpoint blockade therapies. While both tumor and host immune cell-derived PD-L1 are implicated in immune suppressive functions of PD-L1, the exact immunosuppressive contribution of PD-L1 from different host tissues is little studied. Here we show that PD-L1 expression is significantly higher in human breast adipose tissue versus stromal vascular fractions. In vitro adipogenesis of mouse pre-adipocytes significantly up-regulates PD-L1 versus pre-adipocytes. In vitro co-culture shows that adipocyte PD-L1 suppresses T cell activation and response to anti-PD-L1. In an adipocyte-specific knockout (KO) mouse model, we show that syngeneic mammary tumors grow slower in KO than wildtype hosts. Immunophenotyping shows that tumors grown in KO mice have higher CD8+and CD4+ T cell infiltration as well as more CD8+ Prf+ cytotoxic T cells. Tumor tissue RNA-seq analysis reveals that genetic ablation of adipocyte PD-L1 confers a distinct transcriptomic signature of T cell activation and tumor killing. Our current findings uncover a previously unappreciated source of immune suppressive PD-L1 in the breast cancer microenvironment and could inform novel therapeutic strategies through targeting tumor-surrounding adipose tissue for treating breast cancer.

Dexamethasone Attenuates X-Ray-Induced Activation of the Autotaxin-Lysophosphatidate-Inflammatory Cycle in Breast Tissue and Subsequent Breast Fibrosis.

We recently showed that radiation-induced DNA damage in breast adipose tissue increases autotaxin secretion, production of lysophosphatidate (LPA) and expression of LPA1/2 receptors. We also established that dexamethasone decreases autotaxin production and LPA signaling in non-irradiated adipose tissue. In the present study, we showed that dexamethasone attenuated the radiation-induced increases in autotaxin activity and the concentrations of inflammatory mediators in cultured human adipose tissue. We also exposed a breast fat pad in mice to three daily 7.5 Gy fractions of X-rays. Dexamethasone attenuated radiation-induced increases in autotaxin activity in plasma and mammary adipose tissue and LPA1 receptor levels in adipose tissue after 48 h. DEX treatment during five daily fractions of 7.5 Gy attenuated fibrosis by ~70% in the mammary fat pad and underlying lungs at 7 weeks after radiotherapy. This was accompanied by decreases in CXCL2, active TGF-β1, CTGF and Nrf2 at 7 weeks in adipose tissue of dexamethasone-treated mice. Autotaxin was located at the sites of fibrosis in breast tissue and in the underlying lungs. Consequently, our work supports the premise that increased autotaxin production and lysophosphatidate signaling contribute to radiotherapy-induced breast fibrosis and that dexamethasone attenuated the development of fibrosis in part by blocking this process.

Biochemical study on modifying role of variants of leptin gene and its receptor on serum leptin levels in breast cancer.

The leptin is discharged from breast adipose tissue and is overexpressed in breast cancer (BC). Conflicting relation of leptin with BC was reported. We investigated this association and its impact on leptin level and disease characteristics. The study included 70 females (40 women with pathological proof of invasive BC patients and 30 controls). LEP and LEPR polymorphisms were evaluated by real-time PCR. Serum leptin was estimated by ELISA. Both LEPR and LEP disturbances increase the danger of BC where GG genotype and G allele frequencies of LEPR were higher in patients vs. control. GG genotype increases BC risk with OR (9.1) while G allele predisposes to disease with OR (3.8). Furthermore, LEP A allele was uniquely elevated in patients than healthy ones with OR (2.06). Precise relation of circulating leptin and its polymorphisms with predicting BC may authorize its utilization in early screening.

Abstract 177: Effects Of Obesity On Adipose Stromal Cell Biology: Contributions To Breast Cancer Risk

Purpose: Obesity in premenopausal women increases their lifetime risk of developing an aggressive subtype of breast cancer (triple-negative breast cancer; TNBC). Senescent cells are associated with multiple disease states, partially due to their secretion of inflammatory cytokines. We previously demonstrated that BRCA1 mutations, which are associated with increased TNBC risk, directly impact adipose stromal cell (ASC) biology, resulting in cellular senescence and the secretion of inflammatory cytokines. In the current studies, we investigated the hypothesis that ASCs from obese premenopausal women are senescent, and secrete inflammatory cytokines that may contribute to TNBC initiation by acting in a paracrine manner on the breast epithelium. Methods: ASCs were isolated from breast adipose tissue obtained from obese (BMI>30) or lean (BMI<27) women undergoing breast reductions. ASC marker expression (CD44, CD90, CD105) was confirmed by flow cytometry. ASCs from women with differing BMIs were also obtained from Zenbio. Senescence was measured in ASCs by beta galactosidase staining. Cytokines were measured by ELISA in ASC conditioned media. The ability of an IL6 receptor-neutralizing antibody to reverse senescence in obese ASCs was tested. We also tested if recombinant IL6 promotes Stat3 signaling and senescence in ASCs from low BMI patients. Effects of conditioned media from obese ASCs on breast epithelial cell growth were tested. Results: ASCs from obese premenopausal women were senescent and supported autocrine IL6/Stat3 signaling. Treatment of ASCs from lean women with IL6 also promoted Stat3 signaling and senescence. An anti-IL6 receptor antibody blocked autocrine IL6 signaling in ASCs from obese women. We will discuss how this obesity-altered ASC biology may contribute to TNBC initiation. Conclusions: ASCs from obese premenopausal women are senescent, and secrete senescence-associated cytokines that can act in a paracrine fashion on breast epithelial cells to promote cell behaviors associated with breast cancer initiation. Ultimately, determining how obesity impacts ASC biology, and how this biology may drive TNBC initiation, will provide an important foundation for developing ASC-targeting therapies that reduce mortalities associated with TNBC. ASCs from high BMI women are senescent, and produce senescence-associated cytokines that activate Stat3 signaling. A. ASCs from premenopausal women with a BMI of 26.5 or 38 (passage 7) were stained using the Senescence Beta-galactosidase Staining Kit (Cell Signaling Technology). Note increased beta gal staining in BMI 38 ASCs compared to that in BMI 26.5 ASCs. Conditioned media (72 h) were collected from ASCs from women with the indicated BMIs (p7; triplicate wells). IL6 (B) and IL8 (C) were quantified by ELISA (R&D Systems; pg/ml/cell (+/- SD) **, p<0.001). SFM= serum-free media. D. ASCs (BMI 26.5) were pulsed for 10 min with IL6 [rIL6 (R&D Systems;10 pg/mL) +/- soluble IL6R [sIL6R (R&D Systems; 150 pg/mL)]. Equivalent amounts of nuclear protein were immunoblotted with phospho-Stat3 (Tyr705) or GAPDH antibodies (Cell Signaling Technology). Addition of both IL6 and sIL6R increased phospho-Stat3 levels, indicating that these ASCs support trans-IL6 signaling.

Associations between functional polychlorinated biphenyls in adipose tissues and prognostic biomarkers of breast cancer patients

BackgroundExposure to polychlorinated biphenyls (PCBs) has been shown to influence expression of some biomarkers that are predictive/prognostic for breast cancer. Therefore, our study was conducted to further investigating associations of different functional PCBs in adipose tissue with breast cancer prognostic biomarkers. MethodsTwo hundred and five breast cancer patients were recruited in Shantou, China. Breast adipose tissues were collected during their resection surgery and levels of 7 PCB congeners were analyzed by gas chromatography-mass spectrometry (GC-MS). The PCB congeners were divided into 4 groups according to structure-activity. Socio-demographic, clinical and pathological information were obtained from questionnaire and digital medical records. Odds ratios (ORs) for associations between prognostic biomarkers and PCB levels (tertile 3 [T3], tertile 2 [T2] vs. tertile 1) were estimated from logistic regression models. ResultsMost PCB congeners were detectable, with a highest level (22.06 ng/g lipid) of PCB153. As for estrogenic PCBs, increased PCB52 exposure was positively associated with PR expression (ORT2 = 2.36, Ptrend = 0.054), but higher PCB101 level was negatively associated with HER-2 (ORT3 = 0.24, Ptrend = 0.029) and tumor size (OR = 0.43). Limited dioxin-like PCB138 exposure was positively associated with ER (ORT2 = 3.23, ORT3 = 3.77, Ptrend = 0.047) but negatively with Top-IIα expression (ORT2 = 0.35, ORT3 = 0.28, Ptrend = 0.080). Higher PCB153 (CYP inducer) level was negatively associated with ER (ORT2 = 0.32, ORT3 = 0.19, Ptrend = 0.038) but positively with Ki-67 expression (ORT2 = 1.43, ORT3 = 3.60, Ptrend = 0.055). Higher neurotoxic PCB28 was positively associated with HER-2 (ORT3 = 5.43, Ptrend = 0.006) and tumor size (OR = 2.37). Moreover, total PCBs exposure was positively associated with VEGF-C (ORT2 = 76.91, ORT3 = 97.96, Ptrend = 0.041) and tumor metastasis (OR = 2.25). ConclusionsDifferent functional PCB congeners have different associations (both positive and negative) with breast cancer prognostic biomarkers, as well as tumor classification stage. Therefore, the development and aggressiveness of breast cancer may depend upon exposure to specific structure-activity of PCBs.

Obesity Promotes Cooperation of Cancer Stem-Like Cells and Macrophages to Enhance Mammary Tumor Angiogenesis.

Obesity is correlated with worsened prognosis and treatment resistance in breast cancer. Macrophage-targeted therapies are currently in clinical trials, however, little is known about how obesity may impact treatment efficacy. Within breast adipose tissue, obesity leads to chronic, macrophage-driven inflammation, suggesting that obese breast cancer patients may benefit from these therapies. Using a high fat diet model of obesity, we orthotopically transplanted cancer cell lines into the mammary glands of obese and lean mice. We quantified changes in tumor invasiveness, angiogenesis and metastasis, and examined the efficacy of macrophage depletion to diminish tumor progression in obese and lean mice. Mammary tumors from obese mice grew significantly faster, were enriched for cancer stem-like cells (CSCs) and were more locally invasive and metastatic. Tumor cells isolated from obese mice demonstrated enhanced expression of stem cell-related pathways including Sox2 and Notch2. Despite more rapid growth, mammary tumors from obese mice had reduced necrosis, higher blood vessel density, and greater macrophage recruitment. Depletion of macrophages in obese tumor-bearing mice resulted in increased tumor necrosis, reduced endothelial cells, and enhanced recruitment of CD8+ T cells compared to IgG-treated controls. Macrophages may be an important clinical target to improve treatment options for obese breast cancer patients.

Single fiber OCT imager for breast tissue classification based on deep learning.

We investigated a deep learning strategy to analyze optical coherence tomography image for accurate tissue characterization based on a single fiber OCT probe. We obtained OCT data from human breast tissue specimens. Using OCT data obtained from adipose breast tissue (normal tissue) and diseased tissue as confirmed in histology, we trained and validated a convolutional neural network (CNN) for accurate breast tissue classification. We demonstrated tumor margin identification based CNN classification of tissue at different spatial locations. We further demonstrated CNN tissue classification in OCT imaging based on a manually scanned single fiber probe. Our results demonstrated that OCT imaging capability integrated into a low-cost, disposable single fiber probe, along with sophisticated deep learning algorithms for tissue classification, allows minimally invasive tissue characterization, and can be used for cancer diagnosis or surgical margin assessment.

Permanent Pro-Tumorigenic Shift in Adipose Tissue-Derived Mesenchymal Stromal Cells Induced by Breast Malignancy.

During cancer progression, breast tumor cells interact with adjacent adipose tissue, which has been shown to be engaged in cancer aggressiveness. However, the tumor-directed changes in adipose tissue-resident stromal cells affected by the tumor–stroma communication are still poorly understood. The acquired changes might remain in the tissue even after tumor removal and may contribute to tumor relapse. We investigated functional properties (migratory capacity, expression and secretion profile) of mesenchymal stromal cells isolated from healthy (n = 9) and tumor-distant breast adipose tissue (n = 32). Cancer patient-derived mesenchymal stromal cells (MSCs) (MSC-CA) exhibited a significantly disarranged secretion profile and proliferation potential. Co-culture with MDA-MB-231, T47D and JIMT-1, representing different subtypes of breast cancer, was used to analyze the effect of MSCs on proliferation, invasion and tumorigenicity. The MSC-CA enhanced tumorigenicity and altered xenograft composition in immunodeficient mice. Histological analysis revealed collective cell invasion with a specific invasive front of EMT-positive tumor cells as well as invasion of cancer cells to the nerve-surrounding space. This study identifies that adipose tissue-derived mesenchymal stromal cells are primed and permanently altered by tumor presence in breast tissue and have the potential to increase tumor cell invasive ability through the activation of epithelial-to-mesenchymal transition in tumor cells.

Abstract P3-03-12: Obesity promotes the activation of genes and pathways in tumor associated breast fat

Abstract Tumor-associated adipocytes play an active role in breast tumor progression. Moreover, obesity has been established as a risk factor in cancer-related mortality. The altered expression of genes and signaling pathways in breast adipose as a result of obesity may create a more favorable microenvironment for tumor progression. To this end, we analyzed transcriptome profiles of human adipose tissue from lean and obese women with invasive breast cancer using RNA sequencing (n=10/group). Within individuals, adipose tissue was sampled proximal and distal (2 cm) to the breast tumor. A heat map of normalized expression values was generated with unsupervised clustering for the most informative genes. A cluster heat map was obtained by the analysis of the express of 35 DEGs with the most significant differences (adjusted p-value P&amp;lt; 0.01 and fold change &amp;gt; 2) recorded. Starting with a list of genes marked as significant in the analysis of lean vs obese, we queried the STRING database. Using ClusterMaker2 and MCL clustering, we performed enrichment analysis and found KEGG pathway hsa05224 breast cancer was enriched with an FDR of 2.7e-40. Using KEGGParser, we over-layed fold changes from lean vs obese data. In examining obese women, there were 16 Hallmark pathways that were statistically significant (adjusted p-value P&amp;lt; 0.10); whereas a subset of these (11 pathways) were significant in lean women. Pathways that were significant in both lean and obese individuals were pathways that regulate EMT, adipogenesis and TGF-β signaling. EMT transcription factors and TGF-β signaling are known to regulate cancer adipogenesis. The results underscore the link between obesity and altered gene expression in mammary fat associated with breast cancer. (Supported by NIH P20GM103434 and NIGMS U54GM104942) Citation Format: Niel Infante, James Coad, Don Primerano, James Denvir, Linda Vona-Davis. Obesity promotes the activation of genes and pathways in tumor associated breast fat [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-03-12.