Mammary epithelial cells have lineage-rooted metabolic identities

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. Single-cell RNA sequencing of primary human reduction mammoplasty samples Multiplexed using lipid-tagged indices (MULTI-seq) *** Submitter comment: Raw fastq files not supplied as this data is derived from multiplexed samples over mutliple runs as indicated in the RM_count_matrix_metadata.csv file. Additionally, all data presented in the publication can be repeated using the two processed data files uploaded here ***