title: Molecular profiling of a lethal tumor microenvironment, as defined by stromal caveolin-1 status in breast cancers.
abstract: Breast cancer progression and metastasis are driven by complex and reciprocal interactions, between epithelial cancer cells and their surrounding stromal microenvironment. We have previously shown that a loss of stromal Cav-1 expression is associated with an increased risk of early tumor recurrence, metastasis and decreased overall survival. To identify and characterize the signaling pathways that are activated in Cav-1 negative tumor stroma, we performed gene expression profiling using laser microdissected breast cancer-associated stroma. Tumor stroma was laser capture microdissected from 4 cases showing high stromal Cav-1 expression and 7 cases with loss of stromal Cav-1. Briefly, we identified 238 gene transcripts that were upregulated and 232 gene transcripts that were downregulated in the stroma of tumors showing a loss of Cav-1 expression (p ≤ 0.01 and fold-change ≥ 1.5). Gene set enrichment analysis (GSEA) revealed "stemness," inflammation, DNA damage, aging, oxidative stress, hypoxia, autophagy and mitochondrial dysfunction in the tumor stroma of patients lacking stromal Cav-1. Our findings are consistent with the recently proposed "Reverse Warburg Effect" and the "Autophagic Tumor Stroma Model of Cancer Metabolism." In these two complementary models, cancer cells induce oxidative stress in adjacent stromal cells, which then forces these stromal fibroblasts to undergo autophagy/mitophagy and aerobic glycolysis. This, in turn, produces recycled nutrients (lactate, ketones and glutamine) to feed anabolic cancer cells, which are undergoing oxidative mitochondrial metabolism. Our results are also consistent with previous biomarker studies showing that the increased expression of known autophagy markers (such as ATG16L and the cathepsins) in the tumor stroma is specifically associated with metastatic tumor progression and/or poor clinical outcome.
authors.affiliation: Thomas Jefferson University, Philadelphia, PA, USA. agnieszka.witkiewicz@jeferson.edu
authors.forename: Agnieszka K
authors.initials: AK
authors.lastname: Witkiewicz
authors.forename: Jessica
authors.initials: J
authors.lastname: Kline
authors.forename: Maria
authors.initials: M
authors.lastname: Queenan
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Brody
authors.forename: Aristotelis
authors.initials: A
authors.lastname: Tsirigos
authors.forename: Erhan
authors.initials: E
authors.lastname: Bilal
authors.forename: Stephanos
authors.initials: S
authors.lastname: Pavlides
authors.forename: Adam
authors.initials: A
authors.lastname: Ertel
authors.forename: Federica
authors.initials: F
authors.lastname: Sotgia
authors.forename: Michael P
authors.initials: MP
authors.lastname: Lisanti
mesh_terms: D015415:Biomarkers; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D051242:Caveolin 1 / Q000172:deficiency / Q000235:genetics* / Q000502:physiology; D002450:Cell Communication; D005260:Female; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D018384:Oxidative Stress; D059016:Tumor Microenvironment / Q000235:genetics*
chemical_list: D015415:Biomarkers; D051242:Caveolin 1