Project description:Cancer metabolism adapts the metabolic network of its tissue-of-origin. However, breast cancer is not a disease of a singular origin. Multiple epithelial populations serve as the culprit cell-of-origin for specific breast cancer subtypes, yet our knowledge of the metabolic network of normal mammary epithelial cells is limited. Using a multi-OMIC approach, here we identify the diverse metabolic programs operating in normal mammary populations. The proteomes of basal, luminal progenitor, and mature luminal cell populations revealed enrichment of glycolysis in basal cells and of oxidative phosphorylation in luminal progenitors. Single-cell transcriptomes corroborated lineage-specific metabolic identities and additional intra-lineage heterogeneity. Mitochondrial form-and-function differed across lineages, with clonogenicity correlating to mitochondrial activity. Targeting oxidative phosphorylation and glycolysis with inhibitors exposed lineage-rooted metabolic vulnerabilities of mammary progenitors. Bioinformatics indicated breast cancer subtypes retain metabolic features of their putative cell-of-origin. Thus, lineage-rooted metabolic identities of normal mammary cells may underlie breast cancer metabolic heterogeneity and targeting these vulnerabilities could advance breast cancer therapy.
Project description:Global proteomic profiling of three mammary epithelial cell types in normal human breast tissue. Primary breast specimens were obtained from 10 women undergoing reduction mammoplasties. Clinical co-variates include age (28-67), hormone status (follicular, luteal, post-menopausal) and mammary epithelial cell type (basal, luminal progenitor, mature luminal).
Project description:The mammary epithelium depends on specific lineages and their stem and progenitor function to accommodate hormone-triggered physiological demands in the adult female. Perturbations of these lineages underpin breast cancer risk, yet our understanding of normal mammary cell composition is incomplete. Here, we build a multimodal resource for the adult gland through comprehensive profiling of primary cell epigenomes, transcriptomes, and proteomes. We define systems-level relationships between chromatin–DNA–RNA–protein states, identify lineage-specific DNA methylation of transcription factor binding sites, and pinpoint proteins underlying progesterone responsiveness. Comparative proteomics of estrogen and progesterone receptor–positive and –negative cell populations, extensive target validation, and drug testing lead to discovery of stem and progenitor cell vulnerabilities. Top epigenetic drugs exert cytostatic effects; prevent adult mammary cell expansion, clonogenicity, and mammopoiesis; and deplete stem cell frequency. Select drugs also abrogate human breast progenitor cell activity in normal and high-risk patient samples. This integrative computational and functional study provides fundamental insight into mammary lineage and stem cell biology.
PMID: 29921600 (Table S5 and Table S7)
Project description:This submission contains the mass spectrometry files for the manuscript by Aurelie Lacouture et al. that describes the quantitative proteomics analysis of mouse mammary gland epithelial organoids proteome. Experiments were performed from mammary glands organoids derived from mouse and the MS files were acquired on Orbitrap Fusion mass spectrometer. For questions, please contact Etienne Audet-Walsh (Etienne.Audet-Walsh@crchudequebec.ulaval.ca).
Project description:The murine mammary gland is sustained by distinct pools of stem cells that are limited in space and time, exhibiting diverse multipotency and activity. However, the specific identities of these stem cells and their contributions to mammary gland homeostasis are not well understood. In this study, we investigated the spatial heterogeneity of the mammary gland at the single-cell transcription level. Our findings reveal that mammary basal cells exhibit spatially distinct populations and characteristics, which can be further divided based on the expression of Cd34 and Cd200 markers. Notably, Cd34-Cd200+ basal cells demonstrate strong long-term self-renewal ability and possess the highest stem cell frequency, while Cd34+Cd200- basal cells show reduced stem cell potency. Through lineage tracing experiments using their signature genes, we discovered that Bcl11b+ cells were enriched in the Cd34-Cd200+ population and exhibited bipotency even in the postnatal mammary gland, with an increasing contribution to mammary epithelia observed during long-term tracing and after multiple rounds of pregnancies. Conversely, lineage tracing of Sema3a+ cells, enriched in the Cd34+Cd200- population, predominantly revealed their unipotent nature and significant contribution during alveologenesis. Notably, the Bcl11b+ cells displayed a slow response to pregnancy but contributed to long-term mammary homeostasis, in contrast to the rapid response observed in Sema3a+ cells. Importantly, depletion of Bcl11b in Krt14+ mammary basal cells resulted in reduced bipotency of mammary stem cells and impaired their long-term contribution to the mammary gland. Overall, our study identifies distinct bipotent and unipotent populations of mammary basal cells with different dynamic properties that play critical roles in maintaining postnatal mammary homeostasis. These findings are crucial for advancing our understanding of breast health and breast cancer research.