Deep Proteome Profiling of Human Mammary Epithelia at Lineage and Age Resolution

SUMMARYAge 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. 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. Up-regulation 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. Protein expression and phosphorylation changes in the aging breast epithelium identify potential therapeutic targets for reducing breast cancer susceptibility.

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Epigenetic changes with age primes mammary luminal epithelia for cancer initiation

10.1101/2021.02.12.430777 ◽

2021 ◽

Author(s):

Rosalyn W. Sayaman ◽

Masaru Miyano ◽

Parijat Senapati ◽

Sundus Shalabi ◽

Arrianna Zirbes ◽

...

Keyword(s):

Breast Cancer ◽

Gene Expression ◽

Cancer Susceptibility ◽

Epigenetic Changes ◽

Cancer Initiation ◽

Specific Manner ◽

Age Dependent ◽

Mammary Epithelia ◽

Luminal Cells ◽

Differential Variability

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 organizers SATB1 and CTCF. 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 of ESR1-binding regions in DNAm-regulatory CXXC5 in 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.

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Microenvironment-contextual cell signaling is attenuated with age

10.1101/684977 ◽

2019 ◽

Author(s):

Henriette C. Ertsås ◽

Mark A. LaBarge ◽

James B Lorens

Keyword(s):

Breast Cancer ◽

Epithelial Cells ◽

Cell Signaling ◽

Cancer Susceptibility ◽

Breast Cancer Susceptibility ◽

Mammary Epithelial ◽

Specific Marker ◽

Breast Cancers ◽

Age Related ◽

Age Dependent

AbstractPost-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.

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