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PDF file - 972K, Analysis of HMEC lineages in strains derived from reduction mammoplasty (RM) versus peripheral non-tumor regions from mastectomy (P) tissues

PDF file - 2.3MB, Lineage marker distributions in cultured and uncultured HMEC. Sevenparameter flow cytometry analyses of 4th passage HMEC strains

PDF file - 156K, Supplemental Figure 2. CUL4A regulates the transition between epithelial and mesenchymal phenotypes in human normal mammary and cancer cells.

PDF file - 306K, Supplemental Table 1. List of genes significantly differentially expressed after CUL4A overexpression.

PDF file - 176K, Supplemental Figure 5. CUL4A regulates ZEB1 transcriptional expression through H3K4 trimethylation.

PDF file - 293K, Supplemental Figure 3. CUL4A promotes migration and invasion-metastasis of human normal mammary and cancer cells.

PDF file - 62K

The ubiquitin ligase CUL4A has been implicated in tumorigenesis, but its contributions to progression and metastasis have not been evaluated. Here, we show that CUL4A is elevated in breast cancer as well as in ovarian, gastric, and colorectal tumors in which its expression level correlates positively with distant metastasis. CUL4A overexpression in normal or malignant human mammary epithelial cells increased their neoplastic properties in vitro and in vivo, markedly increasing epithelial–mesenchymal transition (EMT) and the metastatic capacity of malignant cells. In contrast, silencing CUL4A in aggressive breast cancer cells inhibited these processes. Mechanistically, we found that CUL4A modulated histone H3K4me3 at the promoter of the EMT regulatory gene ZEB1 in a manner associated with its transcription. ZEB1 silencing blocked CUL4A-driven proliferation, EMT, tumorigenesis, and metastasis. Furthermore, in human breast cancers, ZEB1 expression correlated positively with CUL4A expression and distant metastasis. Taken together, our findings reveal a pivotal role of CUL4A in regulating the metastatic behavior of breast cancer cells. Cancer Res; 74(2); 520–31. ©2013 AACR.

PDF file - 198K, Supplemental Figure 1. CUL4A promotes proliferation of human mammary epithelial and BC cells.

PDF file - 326K, Cultured pre-stasis finite lifespan HMEC at early passage preserve key features of HMEC in vivo

Background A challenge in human mammary epithelial cell (HMEC) culture is sustaining the representation of competing luminal, myoepithelial, and progenitor lineages over time. As cells replicate in culture, myoepithelial cells come to dominate the composition of the culture with serial passaging. This drift in composition presents a challenge for studying luminal and progenitor cells, which are prospective cells of origin for most breast cancer subtypes. Methods We demonstrate the use of postconfluent culture on HMECs. Postconfluent culture entails culturing HMECs for 2–5 weeks without passaging but maintaining frequent feedings in low-stress M87A culture medium. In contrast, standard HMEC culture entails enzymatic subculturing every 3–5 days to maintain subconfluent density. Results When compared to standard HMEC culture, postconfluent culture yields increased proportions of luminal cells and c-Kit+ progenitor cells. Postconfluent cultures develop a distinct multilayered morphology with individual cells showing decreased physical deformability as compared to cells in standard culture. Gene expression analysis of postconfluent cells shows increased expression of lineage-specific markers and extracellular matrix components. Conclusions Postconfluent culture is a novel, useful strategy for altering the lineage composition of HMECs, by increasing the proportional representation of luminal and progenitor cells. We speculate that postconfluent culture creates a microenvironment with cellular composition closer to the physiological state and eases the isolation of scarce cell subtypes. As such, postconfluent culture is a valuable tool for researchers using HMECs for breast cancer research.

We thank C. Thai, A. Sanchez, T. Chevez, A. Nunez and M. V. Robles for their help with tissue collection and clinical information from the women participating in our study. We also thank M. Miyano for assistance with immunofluorescence images, M. Basam for help with coding, and our patient advocates S. Samson and S. Preto for providing much needed context. Funding was provided by: DOD CDMRP (BC141351 Era of Hope Scholar Award and BC181737), Hilton-Ludwig Foundation and City of Hope Center for Cancer and Aging to M.A.L.; National Institutes of Health/National Cancer Institute (NIH/NCI) grants (nos. R01CA237602, U01CA244109, R33AG059206 and R01EB024989 to M.A.L. and nos. R01CA170851, P20CA24619, R01CA192914 and U01CA189283 to V.E.S.) and NCI Cancer Metabolism Training Program Postdoctoral Fellowship T32CA221709 to R.W.S. Research reported in this publication included work performed in the Integrative Genomics and Bioinformatics, Analytical Cytometry, and Biomarker Analysis and Validation Cores supported by the NCI of the NIH under grant no. P30CA033572. M.R.S. and J.C.G. are supported by US Department of Energy under contract no. DE-AC02-05CH11231. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.

A majority of breast cancers (BC) are age-related and we seek to determine what cellular and molecular changes occur in breast tissue with age that make women more susceptible to cancer initiation. Immune-epithelial cell interactions are important during mammary gland development and the immune system plays an important role in BC progression. The composition of human immune cell populations is known to change in peripheral blood with age and in breast tissue during BC progression. Less is known about changes in immune populations in normal breast tissue and how their interactions with mammary epithelia change with age. We quantified densities of T cells, B cells, and macrophage subsets in pathologically normal breast tissue from 122 different women who ranged in age from 24 to 74 years old. Donor-matched peripheral blood from a subset of 20 donors was analyzed by flow cytometry. Tissue immune cell densities and localizations relative to the epithelium were quantified in situ with machine learning-based image analyses of multiplex immunohistochemistry-stained tissue sections. In situ results were corroborated with flow cytometry analyses of peri-epithelial immune cells from primary breast tissue preparations and transcriptome analyses of public data from bulk tissue reduction mammoplasties. Proportions of immune cell subsets in breast tissue and donor-matched peripheral blood were not correlated. Density (cells/mm2) of T and B lymphocytes in situ decreased with age. T cells and macrophages preferentially localized near or within epithelial bilayers, rather than the intralobular stroma. M2 macrophage density was higher than M1 macrophage density and this difference was due to higher density of M2 in the intralobular stroma. Transcriptional signature analyses suggested age-dependent decline in adaptive immune cell populations and functions and increased innate immune cell activity. T cells and macrophages are so intimately associated with the epithelia that they are embedded within the bilayer, suggesting an important role for immune-epithelial cell interactions. Age-associated decreased T cell density in peri-epithelial regions, and increased M2 macrophage density in intralobular stroma suggests the emergence of a tissue microenvironment that is simultaneously immune-senescent and immunosuppressive with age. Supplementary Information The online version contains supplementary material available at 10.1007/s10911-021-09495-2.

Effects from aging in single cells are unpredictable, whereas aging phenotypes at the organ- and tissue-levels tend to appear as stereotypical changes. The mammary epithelium is a bilayer of two major phenotypically and functionally distinct cell lineages, the luminal epithelial and myoepithelial cells. Mammary epithelia exhibit substantial stereotypical changes with age that merits attention because they are putative breast cancer-cells-of-origin. We hypothesize that effects from aging that impinge upon maintenance of lineage fidelity increases susceptibility to cancer initiation. We identified two models of age-dependent changes in gene expression, directional changes and increased variance, which contributed to genome-wide loss of lineage fidelity. Age-dependent variant responses were common to both lineages, whereas directional changes were almost exclusively detected in luminal epithelia and implicated downregulation of chromatin and genome organizers such asSATB1. Epithelial expression of gap junction proteinGJB6increased with age, and modulation ofGJB6expression in heterochronous co-cultures revealed that it provided a communication conduit from myoepithelial cells that drove directional change in luminal cells. Age-dependent luminal transcriptomes comprised a prominent signal detectable in bulk tissue during aging and transition into cancers. A machine learning classifier based on luminal-specific aging distinguished normal from cancer tissue and was predictive of breast cancer subtype. We speculate that luminal epithelia are the ultimate site of integration of the variant responses to aging in their surrounding tissue and that their emergent aging phenotype both endows cells with the ability to become cancer-cells-of-origin and embodies a biosensor that presages cancer susceptibility.

Dysregulation of the transcriptional or translational machinery can alter the stoichiometry of multiprotein complexes and occurs in natural processes such as aging. Loss of stoichiometry has been shown to alter protein complex functions. We provide a protocol and associated code that use omics data to quantify these stoichiometric changes via statistical dispersion utilizing the interquartile range of expression values per grouping variable. This descriptive statistical approach enables the quantification of stoichiometry changes without additional data acquisition. For complete details on the use and execution of this protocol, please refer to Hinz et al. (2021).

There is a plethora of recognized risk factors for breast cancer (BC) with poorly understood or speculative biological mechanisms. The lack of prevention options highlights the importance of understanding the mechanistic basis of cancer susceptibility and finding new targets for breast cancer prevention. Until now, we have understood risk and cancer susceptibility primarily through the application of epidemiology and assessing outcomes in large human cohorts. Relative risks are assigned to various human behaviors and conditions, but in general the associations are weak and there is little understanding of mechanism. Aging is by far the greatest risk factor for BC, and there are specific forms of inherited genetic risk that are well-understood to cause BC. We propose that bringing focus to the biology underlying these forms of risk will illuminate biological mechanisms of BC susceptibility.

During aging in the human mammary gland, luminal epithelial cells lose lineage fidelity by expressing markers normally expressed in myoepithelial cells. We hypothesize that loss of lineage fidelity is a general manifestation of epithelia that are susceptible to cancer initiation. In the present study, we show that histologically normal breast tissue from younger women who are susceptible to breast cancer, as a result of harboring a germline mutation in

Age is the major risk factor in most carcinomas, yet, little is known about the specific reasons aging increases cancer susceptibility. In the mammary gland, luminal epithelial cells rank high as the putative breast cancer cell of origin. Dysregulation of keratin intermediate filament proteins exemplifies a hallmark age-dependent change in luminal cells, which implicates mechanical states unique to cancer susceptible cells. We implemented mechano-node-pore sensing (mechano-NPS), a multi-parametric single-cell analysis that simultaneously measures cell diameter, resistance to compressive deformation, transverse deformation under constant strain, and recovery time after deformation. We demonstrated that the epithelial lineages, chronological ages, and stages of cancer progression of primary human mammary epithelial cells (HMEC) exhibited discrete mechanical phenotypes. We trained a machine learning model that accurately predicted the chronological age of average risk HMEC cells based exclusively on mechanical properties. Application of the model to cells from women who are germline carriers of high-risk cancer-causing mutations showed that they are mechanically old irrespective of their chronological age, suggesting that mechanical states could be a window into detection and prevention of cancer susceptible states. Indeed, this mechano-age model detected high-risk women with >90% accuracy. Mass spectrometry and cell-based functional assays in mammary epithelia revealed that cytoskeleton related proteins keratin 14 (KRT14) and pseudopodium enriched atypical kinase 1 (PEAK1) were key drivers of age-dependent mechanical signatures. Pharmacological and gene silencing approaches that targeted KRT14 and PEAK1 modulated the mechanical age of HMEC and, in the case of PEAK1 modulation, ablated luminal epithelial cells in an age- and lineage- dependent manner. We define an intersection between mechanical phenotypes and novel age-dependent changes in cytoskeleton-related proteins that we hypothesize can be exploited to assess an individual’s breast cancer susceptibility and provide new targets for cancer-prevention strategies. Citation Format: Stefan Hinz, Masaru Miyano, Antigoni Manousopoulou, Rosalyn W. Sayaman, Kristina Y. Aguilera, Michael E. Todhunter, Jennifer C. Lopez, Leo D. Wang, Lydia L. Sohn, Mark A. LaBarge. Aging-dependent emergent mechanical properties of single epithelial cells exploited for detection of breast cancer susceptibility [abstract]. In: Proceedings of the AACR Special Conference: Aging and Cancer; 2022 Nov 17-20; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_1):Abstract nr A016.

Effects from aging in any single cell are unpredictable, whereas aging phenotypes at the organ and tissue levels tend to appear as stereotypical changes. The mammary epithelium, the origin of breast carcinomas, is a bilayer of two major phenotypically and functionally distinct cell lineages, the luminal epithelial and myoepithelial cells. We have shown that luminal epithelia exhibit substantial stereotypical changes with age, which merits attention as they are putative breast cancer cells of origin. Hallmark aging changes in mammary gland are loss of lineage specificity in luminal epithelia exemplified by acquiring expression of proteins normally reserved for myoepithelial cells, and progenitor cells that accumulate and attain a basal differentiation bias. We hypothesize that effects from aging that impinge upon maintenance of lineage specificity increases susceptibility to cancer initiation. Indeed, histologically normal breast tissue from young women, who were known to be highly susceptible to breast cancer because they harbor a germline mutation in BRCA1, BRCA2, or PALB2 genes, exhibited hallmarks of accelerated aging. These included increased proportions of luminal epithelial cells with acquired myoepithelial proteins, acceleration of a breast specific biological clock by 10 to 40 years compared to chronological age, and a basal differentiation bias or failure of differentiation of cKit+ progenitors. To gain insight into the underlying molecular changes we interrogated transcriptomes, proteomes, and methylomes of mammary epithelia at lineage resolution. Strikingly, age-dependent differential gene expression and DNA methylation occurred almost exclusively in luminal epithelia, whereas changes due to increased variance of gene and protein expression occurs in both luminal and myoepithelial lineages. Most gene changes that were previously associated with early breast cancer are detectable as age-driven changes in normal luminal epithelia. The genes with age-dependent differential and variant changes in expression distinguish normal tissue from breast cancers and are predictive of PAM50 breast cancer subtypes. Heterochronus, multilineage, co-cultures demonstrated that the age-dependent phenotype of luminal cells is at least partly dependent on the microenvironment created on the apical surfaces of neighboring myoepithelial cells. We show that increased variance is a substantial outcome of aging and is likely central to understanding increased susceptibility to breast cancer with age. We speculate that the luminal epithelium is a site of integration of the variant responses to aging in their surrounding tissue, and that their emergent phenotype of aging both endows cells with the ability to become a cancer cell of origin and embodies a biosensor that presages one’s cancer susceptibility. Citation Format: Masaru Miyano, Rosalyn W. Sayaman, Parijat Senapati, Stefan Hinz, Victoria E. Seewaldt, Dustin Schones, Mark A. LaBarge. Integrating noise into a signal: Luminal epithelial cells integrate variable responses to aging into stereotypical changes that underlie breast cancer susceptibility [abstract]. In: Proceedings of the AACR Special Conference: Aging and Cancer; 2022 Nov 17-20; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_1):Abstract nr PR006.

This abstract is being presented as a short talk in the scientific program. A full abstract is available in the Short Talks from Proffered Abstracts section (PR006) of the Conference Proceedings. Citation Format: Masaru Miyano, Rosalyn W. Sayaman, Parijat Senapati, Stefan Hinz, Victoria E. Seewaldt, Dustin Schones, Mark A. LaBarge. Integrating noise into a signal: Luminal epithelial cells integrate variable responses to aging into stereotypical changes that underlie breast cancer susceptibility [abstract]. In: Proceedings of the AACR Special Conference: Aging and Cancer; 2022 Nov 17-20; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_1):Abstract nr A003.

SummaryWomen with germline mutations in BRCA1 (BRCA1+/mut) have increased risk for developing hereditary breast cancer1, 2. Cancer initiation in BRCA1+/mut is associated with pre-malignant changes in the breast epithelium including altered differentiation3–5, proliferative stress6 and genomic instability7. However, the role of the epithelium- associated stromal niche during BRCA1-driven tumor initiation remains unclear. Here, we show that the pre-malignant stromal niche promotes epithelial proliferation and BRCA1- driven cancer initiation in trans. Using single-cell RNAseq (scRNAseq) analysis of human pre-neoplastic BRCA1+/mut and control breast tissues, we show that stromal cells provide numerous pro-proliferative paracrine signals inducing epithelial proliferation. We identify a subpopulation of pre-cancer associated fibroblasts (pre-CAFs) that produces copious amounts of pro-tumorigenic factors including matrix metalloproteinase 3 (MMP3)8, 9, and promotes BRCA1-driven tumorigenesis in vivo. Our gene-signature analysis and mathematical modeling of epithelial differentiation reveals that stromal-induced proliferation leads to the accumulation of luminal progenitor cells with altered differentiation, and thus contributes to increased breast cancer risk in BRCA1+/mut. Our results demonstrate how alterations in cell-cell communication can induce imbalances in epithelial homeostasis ultimately leading to cancer initiation. We anticipate our results to form the foundation for novel disease monitoring and therapeutic strategies to improve patient management in hereditary breast cancer. For example, pre-CAF specific proteins may serve as biomarkers for pre-cancerous disease initiation to inform whether radical bilateral mastectomy is needed. In addition, MMP inhibitors could be re-indicated for primary cancer prevention treatment in women with high-risk BRCA1 mutations.

Background: Machine learning relies on algorithms that learn patterns in large, complex datasets to predict outcomes. The adaptive, neoadjuvant I-SPY 2 TRIAL evaluates novel agents added to standard therapy, and identifies their most responsive subtype. While previously proposed genes/signatures reflecting an agent’s mechanism of action predicted pathologic complete response (pCR) in some treatment arms/subtypes, not all arms had strong predictive biomarkers. We leverage machine learning to explore the limitations of using only known mechanisms of action in predicting pCR, and the extent to which biology outside known drug action improves response prediction in the first 10 arms of the trial. Methods: Our study involves 986 patients with pre-treatment gene expression and pCR data across 10 treatment arms including inhibitors of HER2: neratinib (N), pertuzumab (P), TDM1/P; AKT (MK-2206; M); IGF1R (ganitumab); HSP90 (ganetespib); PARP/DNA repair (veliparib/carboplatin; VC); ANG1/2 (AMG386); immune checkpoints (pembrolizumab; Pembro); and a shared control arm (Ctr). Each arm/receptor subtype group was evaluated independently for groups with at least 20 patients (n=19), with 25% of data held out as independent test sets. We implemented a 3-fold cross validation technique with 10 repeats using Random Forest ensemble algorithm with recursive feature elimination. In combination with clinical data, a three-pronged feature-selection approach was employed: (1) restricted to mechanism of action genes: AKT/PI3K/HER (m=10 genes), IGF1 (m=11), HSP90 (m=88), DNA repair (m=79), TIE1/2 (m=11), and immune (m=61), as well as HER2 amplicon genes; (2) expanded to include targeted pathways for all 10 agents/combinations plus ESR1 and proliferation genes (m=339); (3) an unbiased whole genome approach (m=17,990). Models were considered predictive if AUROC ≥ 0.75, Sensitivity ≥ 0.6 and Specificity ≥ 0.6 in cross validation and independent test sets. Results: Table 1 summarizes the results of our analysis (Yes=predictive; NA=no/insufficient data). Prediction of pCR using only genes reflecting the known mechanism of the drug succeeded in 5 subgroups, with DNA repair genes predicting VC response and immune genes predicting Pembro response in HR+HER2- and HR-HER2- subsets, and AKT/PI3K/HER + HER2 amplicon genes predicting (P) response in HR+HER2+ patients. Expansion of the feature set to include genes associated with all mechanisms of action of all drugs proved sufficient to produce good predictive models in 8 of 19 subgroups. Examples include DNA repair + immune genes predicting response to ganitumab in HR+HER2- and to (N) in HR+HER2+. An unbiased approach using all data yielded predictive power in 8 of 19 subgroups, including 5 with no predictive models from the first two approaches. Examples include HR-HER2- (N) predictors enriched for metabolic, cell division and membrane protein proteolytic processes; HR+HER2+ TDM1/P enriched for metabolic, stress response and cell cycle processes; and HR-HER2- MK-2206 predictors containing Ser/Thr kinases. In total, we identify predictive biomarkers in 14 of 19 subgroups across the three feature selection approaches. Conclusion: Our results suggests that hypothesis driven analysis restricted to assumed mechanisms of action of the experimental agents may be insufficient, and that exploration of possible off target effects may be needed to understand the underlying biology of response or resistance. Table 1. Model results across feature selection approachesHR+HER2-HR-HER2-HR+HER2+HR-HER2+Number of PatientsMechanism of ActionAll Mechanisms of ActionUnbiasedNumber of PatientsMechanism of ActionAll Mechanisms of ActionUnbiasedNumber of PatientsMechanism of ActionAll Mechanisms of ActionUnbiasedNumber of PatientsMechanism of ActionAll Mechanisms of ActionUnbiasedneratinib (pan anti-HER)NA32NoNoYes42NoYesYes23NoNoYespertuzumab (anti-HER2)NANA29YesYesNoNATDM1/Pertuzumab (anti-HER2)NANA35NoNoYesNAMK−2206 (AKT inhibitor)28NoNoNo32NoNoYesNANAganitumab (IGFR inhibitor)58NoYesNo48NoNoNoNANAganetespib (HSP90 inhibitor)48NoYesYes45NoNoNoNANAvelirapib/carboplatin (PARP inhibitor/DNA damage)33YesYesNo39YesYesNoNANAAMG386 (ANG1/2 inhibitor)62NoYesYes53NoNoNoNANApembrolizumab (immune checkpoint inhibitor)38YesYesNo29YesNoNoNANAHER2+ controlNANANANAHER2- control94NoNoYes84NoNoNoNANA Citation Format: Rosalyn W. Sayaman, Denise M. Wolf, Christina Yau, Julie Wulfkuhle, Emanuel Petricoin, Lamorna Brown-Swigart, Smita M. Asare, Gillian L. Hirst, Laura Sit, Nicholas O'Grady, Diane Hedistian, I-SPY 2 TRIAL Consortium, Laura J. Esserman, Mark A. LaBarge, Laura J van 't Veer. Application of machine learning to elucidate the biology predicting response in the I-SPY 2 neoadjuvant breast cancer trial [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 P1-21-08.

Background: Exposure to polybrominated diphenyl ethers (PBDEs) may influence risk of developing post-menopausal breast cancer. Although mechanisms are poorly understood, epigenetic regulation of gene expression may play a role. Objectives: To identify DNA methylation (DNAm) changes associated with PBDE serum levels and test the association of these biomarkers with breast cancer risk. Methods: We studied 397 healthy women (controls) and 133 women diagnosed with breast cancer (cases) between ages 40 and 58 years who participated in the California Teachers Study. PBDE levels were measured in blood. Infinium Human Methylation EPIC Bead Chips were used to measure DNAm. Using multivariable linear regression models, differentially methylated CpG sites (DMSs) and regions (DMRs) associated with serum PBDE levels were identified using controls. For top-ranked DMSs and DMRs, targeted next-generation bisulfite sequencing was used to measure DNAm for 133 invasive breast cancer cases and 301 age-matched controls. Conditional logistic regression was used to evaluate associations between DMSs and DMRs and breast cancer risk. Results: We identified 15 DMSs and 10 DMRs statistically significantly associated with PBDE levels (FDR

Cellular mechanical properties can reveal physiologically relevant characteristics in many cell types, and several groups have developed microfluidics-based platforms to perform single-cell mechanical testing with high throughput. However, prior work has performed only limited characterization of these platforms’ technical variability and reproducibility. Here, we evaluate the repeatability performance of mechano-node-pore sensing, which is a single-cell mechanical phenotyping platform developed by our research group. We measured the degree to which device-to-device variability and semi-manual data processing affected this platform’s measurements of single-cell mechanical properties, and we demonstrated high repeatability across the entire technology pipeline even for novice users. We then compared results from identical mechano-node-pore sensing experiments performed by researchers in two different labs with different analytical instruments, demonstrating that the mechanical testing results from these two locations are in agreement. Our findings quantify the expectation of technical variability in mechano-node-pore sensing even in minimally experienced hands. Most importantly, we find that the repeatability performance we measured is fully sufficient for interpreting biologically relevant single-cell mechanical measurements with high confidence.

Background : A majority of breast cancers (BC) are age-related and we seek to determine what cellular and molecular changes occur in breast tissue with age that make women more susceptible to cancer initiation. Immune-epithelial cell interactions are important during mammary gland development and the immune system plays an important role in BC progression. The composition of human immune cell populations is known to change in peripheral blood with age and in breast tissue during BC progression. Less is known about changes in immune populations in normal breast tissue and how their interactions with mammary epithelia change with age. Methods : We quantified densities of T cells, B cells, and macrophage subsets in pathologically normal breast tissue from 122 different women who ranged in age from 24 to 74 years old. Donor-matched peripheral blood from a subset of 20 donors was analyzed by flow cytometry. Tissue immune cell densities and localizations relative to the epithelium were quantified in situ with machine learning-based analyses of multiplex immunohistochemistry-stained tissue sections. In situ results were corroborated with flow cytometry analyses of peri-epithelial immune cells from primary organoid preparations and transcriptome analyses of public data from bulk tissue reduction mammoplasties. Results : Proportions of immune cell subsets in breast tissue and donor-matched peripheral blood were not correlated. Density (cells/mm 2 ) of T and B lymphocytes in situ decreased with age. T cells and macrophages preferentially localized near or within epithelial bilayers, rather than the intralobular stroma. M2:M1 macrophage ratio increased with age and was accompanied by an increased density of M2 in the intralobular stroma. Transcriptional signature analyses suggested age-dependent decline in adaptive immune cell populations and functions and increased innate immune cell activity. Conclusions : T cells and macrophages are so intimately associated with the epithelia that they are embedded within the bilayer, suggesting an important role for immune-epithelial cell interactions. Age-associated decreased T cell density in peri-epithelial regions, and increased M2 macrophage density in intralobular stroma suggests the emergence of a tissue microenvironment that is simultaneously immune-senescent and immunosuppressive with age .

Yap and Taz are co-transcription factors that have been implicated in the development of many cancers. Here, we review the literature that analyzes the function of Yap/Taz in normal breast and breast cancer contexts. Our review of the literature suggests that that Yap and Taz are involved in breast cancer and Taz, in particular, is involved in the triple negative subtype. Nevertheless, the precise contexts in which Yap/Taz contribute to specific breast cancer phenotypes remains unclear. Indeed, Yap/Taz dysregulation acts differentially and in multiple epithelial cell types during early breast cancer progression. We propose Yap/Taz activation promotes breast cancer phenotypes in breast cancer precursor cells. Further, Yap dysregulation as a result of aging in breast tissue may result in microenvironments that increase the fitness of breast cancer precursor cells relative to the normal epithelia.

Summary Age is the major risk factor in most carcinomas, yet little is known about how proteomes change with age in any human epithelium. We present comprehensive proteomes comprised of >9,000 total proteins and >15,000 phosphopeptides from normal primary human mammary epithelia at lineage resolution from ten women ranging in age from 19 to 68 years. Data were quality controlled and results were biologically validated with cell-based assays. Age-dependent protein signatures were identified using differential expression analyses and weighted protein co-expression network analyses. Upregulation of basal markers in luminal cells, including KRT14 and AXL, were a prominent consequence of aging. PEAK1 was identified as an age-dependent signaling kinase in luminal cells, which revealed a potential age-dependent vulnerability for targeted ablation. Correlation analyses between transcriptome and proteome revealed age-associated loss of proteostasis regulation. Age-dependent proteome changes in the breast epithelium identified heretofore unknown potential therapeutic targets for reducing breast cancer susceptibility., Graphical abstract, Highlights • Age-dependent proteomic profiling of HMECs at lineage resolution • Loss of proteostasis is unique to the luminal epithelial lineage with age • Identification of co-regulated proteins with age in luminal cells including PEAK1 • PEAK1 inhibition selectively ablates older luminal cells – cancer cell of origin, Developmental biology; Complex system biology; Proteomics

SummaryAging causes molecular changes that manifest as stereotypical phenotypes yet aging-associated diseases progress only in certain individuals. At lineage-specific resolution, we show how stereotyped and variant responses are integrated in mammary epithelia. Age-dependent directional changes in gene expression and DNA methylation (DNAm) occurred almost exclusively in luminal cells and implicated genome organizersSATB1andCTCF. DNAm changes were robust indicators of aging luminal cells, and were either directly (anti-)correlated with expression changes or served as priming events for subsequent dysregulation, such as demethylation ofESR1-binding regions in DNAm-regulatoryCXXC5in older luminal cells and luminal-subtype cancers. Variance-driven changes in the transcriptome of both luminal and myoepithelial lineages further contributed to age-dependent loss of lineage fidelity. The pathways affected by transcriptomic and DNAm changes during aging are commonly linked with breast cancer, and together with the differential variability found across individuals, influence aging-associated cancer susceptibility in a subtype-specific manner.

Purified populations of cells can be reconstituted into organoids that recapitulate aspects of their in vivo structure and function. These organoids are useful as models of healthy and diseased tissue in the basic sciences, in vitro screens, and regenerative medicine. Existing strategies to reconstitute organoids from purified cells face obstacles with respect to cell-viability, multicellular connectivity, scalability, and compatibility with subsequent experimental or analytical techniques. To address these challenges, we developed a strategy for rapidly casting populations of cells into microtissues of prescribed size and shape. This approach begins by chemically remodeling the adhesive properties of living cells with membrane-anchored ssDNA with modest annealing kinetics. Populations of complementary labeled cells are then combined into microwells that rapidly mold the DNA-adhesive cell populations into 3D aggregates of uniform size and shape. Once formed, aggregates are removed from the molds in the presence of "capping" oligonucleotides that block hybridization of residual surface DNA between aggregates in suspension. Finally, transfer of aggregates to biomimetic gels for 3D culture completes the process of reconstitution. This strategy of chemical micromolding allows for control over aggregate internal topology and does not perturb the natural process of self-organization in primary human mammary epithelial cells.

A robust breast cancer prevention strategy requires risk assessment biomarkers for early detection. We show that expression of ELF5, a transcription factor critical for normal mammary development, is downregulated in mammary luminal epithelia with age. DNA methylation of the ELF5 promoter is negatively correlated with expression in an age-dependent manner. Both ELF5 methylation and gene expression were used to build biological clocks to estimate chronological ages of mammary epithelia. ELF5 clock-based estimates of biological age in luminal epithelia from average-risk women were within three years of chronological age. Biological ages of breast epithelia from BRCA1 or BRCA2 mutation carriers, who were high risk for developing breast cancer, suggested they were accelerated by two decades relative to chronological age. The ELF5 DNA methylation clock had better performance at predicting biological age in luminal epithelial cells as compared with two other epigenetic clocks based on whole tissues. We propose that the changes in ELF5 expression or ELF5-proximal DNA methylation in luminal epithelia are emergent properties of at-risk breast tissue and constitute breast-specific biological clocks. Prevention Relevance: ELF5 expression or DNA methylation level at the ELF5 promoter region can be used as breast-specific biological clocks to identify women at higher than average risk of breast cancer.

A robust breast cancer prevention strategy requires risk assessment biomarkers for early detection. We show that expression of ELF5, a transcription factor critical for normal mammary development, is downregulated in mammary luminal epithelia with age. DNA-methylation of the ELF5 promoter is negatively correlated with expression in an age-dependent manner. Both ELF5 methylation and gene expression were used to build biological clocks to estimate chronological ages of mammary epithelia. ELF5 clock-based estimates of biological age in luminal epithelia from average-risk women were within 3 years of chronological age. Biological ages of breast epithelia from BRCA1 or BRCA2 mutation carriers, who were high risk for developing breast cancer, suggested they were accelerated by two decades relative to chronological age. The ELF5 DNA methylation clock had better performance at predicting biological age in luminal epithelial cells as compared to two other epigenetic clocks based on whole tissues. We propose that the changes in ELF5 expression or ELF5-proximal DNA methylation in luminal epithelia are emergent properties of at-risk breast tissue and constitute breast-specific biological clocks.

PURPOSE OF REVIEW: Cancer stem cells (CSCs) are increasingly understood to play a central role in tumor progression. Growing evidence implicates tumor microenvironments as a source of signals that regulate or even impose CSC states on tumor cells. This review explores points of integration for microenvironment-derived signals that are thought to regulate CSCs in carcinomas. RECENT FINDINGS: CSC states are directly regulated by the mechanical properties and extra cellular matrix (ECM) composition of tumor microenvironments that promote CSC growth and survival, which may explain some modes of therapeutic resistance. CSCs sense mechanical forces and ECM composition through integrins and other cell surface receptors, which then activate a number of intracellular signaling pathways. The relevant signaling events are dynamic and context-dependent. SUMMARY: CSCs are thought to drive cancer metastases and therapeutic resistance. Cells that are in CSC states and more differentiated states appear to be reversible and conditional upon the components of the tumor microenvironment. Signals imposed by tumor microenvironment are of a combinatorial nature, ultimately representing the integration of multiple physical and chemical signals. Comprehensive understanding of the tumor microenvironment-imposed signaling that maintains cells in CSC states may guide future therapeutic interventions.

Luminal epithelial cells (LEps) are a key cell lineage implicated in age-related luminal breast cancers. Alterations to the epigenome are a hallmark of aging cells. However, the extent of age-associated DNA methylation alterations in LEps, and the corresponding functional consequences of these alterations, have remained unclear. We report here that aging leads to distinct methylation changes in LEps. Luminal lineage-specific genes gain promoter methylation, whereas myoepithelial-specific genes lose promoter methylation. Regulatory elements display methylation changes at lineage-specific TF binding sites consistent with the loss of lineage fidelity. CpG islands (CGIs) and transposable elements (TEs) have stochastic methylation gain and loss, respectively. PRC2 target genes that are hypermethylated in luminal breast cancer exhibit stochastic methylation increase with age. TEs with stochastic methylation loss are activated in breast cancer and potentially function as regulatory elements contributing to the loss of lineage fidelity with age. Each of these classes of methylation changes impact the regulation of genes associated with luminal breast cancer. Altogether, our results indicate that aging leads to DNA methylation changes that could determine breast cancer susceptibility.SignificanceMammary luminal epithelial cells lose lineage-specific expression with age and accumulate stochastic methylation changes that lead to loss of silencing at transposable elements. These age-dependent events potentially promote breast cancer susceptibility.

The novel COVID-19 outbreak started in 2019 in Wuhan China and quickly spread to at least 185 countries. We developed an interactive web application that allows users to visualize the spread of COVID-19 in the Unites States at state and county levels. This tool allows visualization of how the virus spreads over time and how state-wide efforts to reduce transmissions have affected the curve in local areas. The downloadable application data allows users to conduct additional analyses. We demonstrate exemplars of trend analyses comparing the daily infection and death rates before and after safer at home orders were implemented per state. The goal was to develop a COVID-19 tracking tool that informs users about the spread of the virus to enable them to make informed decisions after better understanding the presented data.

During aging in the human mammary gland, luminal epithelial cells lose lineage fidelity by expressing markers normally expressed in myoepithelial cells. We hypothesize that loss of lineage fidelity is a general manifestation of epithelia that are susceptible to cancer initiation. We show that histologically normal breast tissue from younger women who are susceptible to breast cancer because they harbor a germline mutation in BRCA1, BRCA2, or PALB2 genes, exhibit hallmarks of accelerated aging. These include proportionately increased luminal epithelial cells that acquired myoepithelial markers, decreased proportions of myoepithelial cells, and a basal differentiation bias or failure of differentiation of cKit+ progenitors. High-risk luminal and myoepithelial cells are transcriptionally enriched for genes of the opposite lineage, inflammatory, and cancer-related pathways. Genetically high risk luminal epithelial cells also show evidence of accelerated age, by as much as four decades compared to their chronological age, using a breast specific biological clock comprised of measurements of methylation and expression of the luminal-specific ELF5 transcription factor. We have identified breast aging hallmarks that reflect a convergent biology of cancer susceptibility, regardless of the specific underlying genetic or age-dependent risk, or the associated breast cancer subtype. Citation Format: Masaru Miyano, Sundus Shalabi, Rosalyn W. Sayaman, Martha Stampfer, Victoria E. Seewaldt, Mark A. LaBarge. Accelerated biological age is a driver of cancer susceptibility in genetic high risk breast tissue [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5682.

Aging is driven by unavoidable entropic forces, physicochemical in nature, that damage the raw materials that constitute biological systems. Single cells experience and respond to stochastic physicochemical insults that occur either to the cells themselves or to their microenvironment, in a dynamic and reciprocal manner, leading to increased age-related cell-to-cell variation. We will discuss the biological mechanisms that integrate cell-to-cell variation across tissues resulting in stereotypical phenotypes of age.

The Library of Integrated Network-Based Cellular Signatures (LINCS) is an NIH Common Fund program that catalogs how human cells globally respond to chemical, genetic, and disease perturbations. Resources generated by LINCS include experimental and computational methods, visualization tools, molecular and imaging data, and signatures. By assembling an integrated picture of the range of responses of human cells exposed to many perturbations, the LINCS program aims to better understand human disease and to advance the development of new therapies. Perturbations under study include drugs, genetic perturbations, tissue micro-environments, antibodies, and disease-causing mutations. Responses to perturbations are measured by transcript profiling, mass spectrometry, cell imaging, and biochemical methods, among other assays. The LINCS program focuses on cellular physiology shared among tissues and cell types relevant to an array of diseases, including cancer, heart disease, and neurodegenerative disorders. This Perspective describes LINCS technologies, datasets, tools, and approaches to data accessibility and reusability.

Summary: The epidemiological association between disrupted circadian rhythms and metabolic diseases is implicated in increased risk of human breast cancer and poor therapeutic outcomes. To define a metabolic phenotype and the underlying molecular mechanism, we applied chronic insulin treatment (CIT) to an in vitro model of triple-negative breast cancer to directly address how BMAL1, a key circadian transcription factor, regulates cancer cell respiration and governs tumor progression. At the cellular level, BMAL1 suppresses the flexibility of mitochondrial substrate usage and the pyruvate-dependent mitochondrial respiration induced by CIT. We established an animal model of diet-induced obesity/hyperinsulinemia and observed that BMAL1 functions as a tumor suppressor in obese, but not lean, mice. Downregulation of BMAL1 is associated with higher risk of metastasis in human breast tumors. In summary, loss of BMAL1 in tumors confers advantages to cancer cells in both intrinsic mitochondrial metabolism and extrinsic inflammatory tumor microenvironment during pre-diabetic obesity/hyperinsulinemia. : Biological Sciences; Cell Biology; Chronobiology; Cancer Subject Areas: Biological Sciences, Cell Biology, Chronobiology, Cancer

Summary The receptor tyrosine kinase AXL is associated with epithelial plasticity in several solid tumors including breast cancer and AXL-targeting agents are currently in clinical trials. We hypothesized that AXL is a driver of stemness traits in cancer by co-option of a regulatory function normally reserved for stem cells. AXL-expressing cells in human mammary epithelial ducts co-expressed markers associated with multipotency, and AXL inhibition abolished colony formation and self-maintenance activities while promoting terminal differentiation in vitro. Axl-null mice did not exhibit a strong developmental phenotype, but enrichment of Axl+ cells was required for mouse mammary gland reconstitution upon transplantation, and Axl-null mice had reduced incidence of Wnt1-driven mammary tumors. An AXL-dependent gene signature is a feature of transcriptomes in basal breast cancers and reduced patient survival irrespective of subtype. Our interpretation is that AXL regulates access to epithelial plasticity programs in MaSCs and, when co-opted, maintains acquired stemness in breast cancer cells., Graphical Abstract, Highlights • AXL + mammary epithelial cells have multipotent activity conserved in women and mice • AXL allows accesses to epithelial-to-mesenchymal transition genes and prevents differentiation into luminal cells • Deletion of Axl reduced incidence of Wnt1-driven tumors in mice • Provides a rationale explaining the advantage to cancer cells that co-opt AXL signaling, Cell Biology; Stem Cells Research; Cancer

Post-menopausal women are more prone to breast cancer than younger women. The increased frequency of age-related breast cancers is likely due to interactions between acquired mutations and age-dependent epigenetic changes that affect mammary epithelial lineage fidelity. We hypothesized that the aging process fundamentally affects how human mammary epithelial cells (HMEC) respond to microenvironmental signals, resulting in increased susceptibility to oncogenic transformation. In order to measure microenvironmental cell signaling in normal finite lifespan HMEC, we applied a novel microsphere-based flow cytometry technology. The microsphere cytometry allows multiparametric single cell quantification of signaling pathway activity and lineage-specific marker expression in cells adhered to surface-functionalized microspheres that mimic specific microenvironments. Using this approach, we analyzed age-dependent changes in human mammary myoepithelial and luminal epithelial cells exposed to different ECM and growth factors. We found that ECM–mediated MAP kinase and PI3 kinase activation levels in HMEC were attenuated with age. Older luminal cells displayed higher surface integrin levels consistent with acquired basal identity, albeit with decreased integrin activation and increased Src-signaling relative to myoepithelial cells. We show that the diminished signaling magnitude in HMEC from older women correlated with reduced probability of activating oncogene-induced senescence. We propose that age-related changes in ECM-mediated epithelial cell regulation may impair protective tumor suppression mechanisms and increase breast cancer susceptibility.

The relevance and impact of human subject research on clinical practice depends on whether the study population reflects the age distribution and health characteristic profiles of the general population. Older adults with a cancer are disproportionately underrepresented in clinical trials and fewer data are available to assess the risks and benefits of cancer treatments, particularly adverse effects on functional outcomes and quality of life1. Furthermore, there is a lack of understanding of how the underlying biologic processes of aging affect tolerance of cancer treatment and survival outcomes. In 2010, the Cancer and Aging Research Group (CARG) outlined the following gaps in generating high quality research in older adults with cancer: 1) clinical measures most relevant to older adults are rarely incorporated into oncology clinical trials; 2) biological and physiological markers of aging are inconsistently included in oncology research; 3) a need for more studies of vulnerable older adults and/or those aged 75 years or older; and 4) limited research infrastructure to support collaborations between geriatrics and oncology.2 Almost a decade later, CARG has been awarded a five-year R21/R33 grant to develop a sustainable national research infrastructure to create and support significant and innovative projects at the interface of cancer and aging that address the four gaps that were initially identified. As a component of this infrastructure award, interactive Cores were developed to facilitate and support aging-related research in oncology. The purpose of this perspective is to summarize the mission and proposed function, process and procedures for Core 1: Clinical and Biological Measures of Aging; and to provide examples of how the Core will facilitate research in geriatric oncology.

Summary A long-standing constraint on organoid culture is the need to add exogenous substances to provide hydrogel matrix, which limits the study of fully human or fully native organoids. This paper introduces an approach to culture reconstituted mammary organoids without the impediment of exogenous matrix. We enclose organoids in nanoliter-scale, topologically enclosed, fluid compartments surrounded by agar. Organoids cultured in these “microcontainers” appear to secrete enough extracellular matrix to yield a self-sufficient microenvironment without exogenous supplements. In microcontainers, mammary organoids exhibit contractility and a high-level, physiological, myoepithelial (MEP) behavior that has not been previously reported in reconstituted organoids. The presence of contractility suggests that microcontainers elicit MEP functional differentiation, an important milestone. Microcontainers yield thousands of substantially identical and individually trackable organoids within a single culture vessel, enabling longitudinal studies and statistically powerful experiments, such as the evaluation of small effect sizes. Microcontainers open new doors for researchers who rely on organoid models., Graphical abstract, Highlights • Microcontainers are volume-constrained microwells with hydrogel lids • Microcontainers enable statistically robust experimental design with organoids • Organoids produce their own extracellular matrix within microcontainers • Myoepithelial cells in mammary organoids achieve fully functional differentiation, Cell Biology; Stem Cells Research; Bioengineering; Tissue Engineering

Background: Physical resilience, the ability to resist decline and maintain functional status despite a stressor such as chemotherapy, is a central aspect of successful aging. Understanding clinical and biological factors associated with resilience in older women receiving chemotherapy for early breast cancer may facilitate the development of targeted interventions to maintain an individual’s robustness.Methods: Women age ≥65 (N=406) with Stage I-III breast cancer who were part of a clinical study of neo/adjuvant chemotherapy in older women were recruited from 16 sites (NCT01472094, R01AG037037). The Deficit Accumulation Index (DAI), a continuous score (0-1) calculated based on 51-items from geriatric assessment data (Cohen et al Cancer 2017), was measured before and after receipt of chemotherapy. DAI was categorized as robust (0.0 12 weeks, and 74% received primary prophylaxis with WBC growth factors. Among these 324 robust older women, 253 (78%) remained robust (resilient) at the end of chemotherapy, 63 (19%) became prefrail, and 8 (3%) became frail. In univariate analyses, patients treated with anthracycline (OR=0.63, p=0.09), planned duration of treatment > 12 weeks (OR=0.56, p=0.04), elevated IL-6 ≥2.7 pg/ml (OR=0.59, p=0.05), elevated CRP ≥4.3 μg/ml (OR=0.57, p=0.04), elevated D-dimer ≥0.7 μg/ml (OR=0.61, p=0.07), or at least one elevated biomarker (OR=0.18, p Conclusions: In this cohort of older women with early breast cancer who were robust prior to initiation of chemotherapy, 22% became prefrail or frail at end of treatment. Resilience to chemotherapy was related to inflammatory and coagulation biomarkers. Further research is needed to examine the mechanism underlying why some older women are resilient and retain their robustness after receiving treatment, whereas others experience decline, and further explore the role of inflammation/coagulation in this phenomenon. Table 1. Multivariable associations between baseline blood biomarkers and resilienceResilient (n=253) No. %Non-resilient (n=71) No. %Multivariable OR (95%CI)P value# of elevated biomarkers*064 (25)4 (6)1.00190 (36)29 (41)0.16 (0.05-0.55)0.004255 (22)22 (31)0.14 (0.04-0.49)0.002344 (17)16 (23)0.14 (0.04-0.51)0.003No elevated biomarker64 (25)4 (6)1.00At least one elevated189 (75)67 (94)0.15 (0.04-0.49)0.002*Biomarkers were defined as elevated using the entire cohort median value as cut off points (IL-6 ≥2.7 pg/ml, CRP ≥4.3 μg/ml, and D-dimer ≥0.7 μg/ml). Combined effects of biomarkers were examined by creating a four-level categorical combination variable: 0=all three biomarkers are Citation Format: Mina S Sedrak, Canlan Sun, Hyman Muss, Rachel A. Freedman, Allison Magnuson, Cary P. Gross, William P. Tew, Heidi D. Klepin, Tanya M. Wildes, Efrat Dotan, Tracey O'Connor, Mary Ann Fenton, Ruby Sharma, Andrew Chapman, Cynthia Owusu, Selina Chow, Heeyoung Kim, Vani Katheria, Mark LaBarge, William Dale, Saro Armenian, Susan Neuhausen, Harvey J. Cohen. Inflammation and coagulation biomarkers associated with physical resilience in older women receiving chemotherapy for early breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS8-03.