title: JNK1 stress signaling is hyper-activated in high breast density and the tumor stroma: connecting fibrosis, inflammation, and stemness for cancer prevention.
abstract: Mammography is an important screening modality for the early detection of DCIS and breast cancer lesions. More specifically, high mammographic density is associated with an increased risk of breast cancer. However, the biological processes underlying this phenomenon remain largely unknown. Here, we re-interrogated genome-wide transcriptional profiling data obtained from low-density (LD) mammary fibroblasts (n = 6 patients) and high-density (HD) mammary fibroblasts (n = 7 patients) derived from a series of 13 female patients. We used these raw data to generate a "breast density" gene signature consisting of>1250 transcripts that were significantly increased in HD fibroblasts, relative to LD fibroblasts. We then focused on the genes that were increased by ≥ 1.5-fold (P<0.05) and performed gene set enrichment analysis (GSEA), using the molecular signatures database (MSigDB). Our results indicate that HD fibroblasts show the upregulation and/or hyper-activation of several key cellular processes, including the stress response, inflammation, stemness, and signal transduction. The transcriptional profiles of HD fibroblasts also showed striking similarities to human tumors, including head and neck, liver, thyroid, lung, and breast cancers. This may reflect functional similarities between cancer-associated fibroblasts (CAFs) and HD fibroblasts. This is consistent with the idea that the presence of HD fibroblasts may be a hallmark of a pre-cancerous phenotype. In these biological processes, GSEA predicts that several key signaling pathways may be involved, including JNK1, iNOS, Rho GTPase(s), FGF-R, EGF-R, and PDGF-R-mediated signal transduction, thereby creating a pro-inflammatory, pro-proliferative, cytokine, and chemokine-rich microenvironment. HD fibroblasts also showed significant overlap with gene profiles derived from smooth muscle cells under stress (JNK1) and activated/infected macrophages (iNOS). Thus, HD fibroblasts may behave like activated myofibroblasts and macrophages, to create and maintain a fibrotic and inflammatory microenvironment. Finally, comparisons between the HD fibroblast gene signature and breast cancer tumor stroma revealed that JNK1 stress signaling is the single most significant biological process that is shared between these 2 data sets (with P values between 5.40E-09 and 1.02E-14), and is specifically associated with tumor recurrence. These results implicate "stromal JNK1 signaling" in the pathogenesis of human breast cancers and the transition to malignancy. Augmented TGF-β signaling also emerged as a common feature linking high breast density with tumor stroma and breast cancer recurrence (P = 5.23E-05). Similarities between the HD fibroblast gene signature, wound healing, and the cancer-associated fibroblast phenotype were also noted. Thus, this unbiased informatics analysis of high breast density provides a novel framework for additional experimental exploration and new hypothesis-driven breast cancer research, with a focus on cancer prevention and personalized medicine.
authors.affiliation: Breakthrough Breast Cancer Research Unit and the Manchester Breast Centre; Institute of Cancer Sciences; University of Manchester; Manchester, UK; Manchester Centre for Cellular Metabolism (MCCM); University of Manchester; Manchester, UK.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Lisanti
authors.affiliation: Computational Biology Center; IBM T.J. Watson Research Center; Yorktown Heights, NY USA.
authors.forename: Aristotelis
authors.initials: A
authors.lastname: Tsirigos
authors.affiliation: Postgraduate Research Institute of Science, Technology, Environment and Medicine (PRI); Limassol, Cyprus.
authors.forename: Stephanos
authors.initials: S
authors.lastname: Pavlides
authors.affiliation: Breakthrough Breast Cancer Research Unit and the Manchester Breast Centre; Institute of Cancer Sciences; University of Manchester; Manchester, UK; Manchester Centre for Cellular Metabolism (MCCM); University of Manchester; Manchester, UK.
authors.forename: Kimberley Jayne
authors.initials: KJ
authors.lastname: Reeves
authors.affiliation: Breakthrough Breast Cancer Research Unit and the Manchester Breast Centre; Institute of Cancer Sciences; University of Manchester; Manchester, UK; Manchester Centre for Cellular Metabolism (MCCM); University of Manchester; Manchester, UK.
authors.forename: Maria
authors.initials: M
authors.lastname: Peiris-Pagès
authors.affiliation: Breakthrough Breast Cancer Research Unit and the Manchester Breast Centre; Institute of Cancer Sciences; University of Manchester; Manchester, UK; Manchester Centre for Cellular Metabolism (MCCM); University of Manchester; Manchester, UK.
authors.forename: Amy L
authors.initials: AL
authors.lastname: Chadwick
authors.affiliation: Breakthrough Breast Cancer Research Unit and the Manchester Breast Centre; Institute of Cancer Sciences; University of Manchester; Manchester, UK; Manchester Centre for Cellular Metabolism (MCCM); University of Manchester; Manchester, UK.
authors.forename: Rosa
authors.initials: R
authors.lastname: Sanchez-Alvarez
authors.affiliation: Breakthrough Breast Cancer Research Unit and the Manchester Breast Centre; Institute of Cancer Sciences; University of Manchester; Manchester, UK; Manchester Centre for Cellular Metabolism (MCCM); Institute of Human Development; University of Manchester; Manchester, UK.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Lamb
authors.affiliation: Breakthrough Breast Cancer Research Unit and the Manchester Breast Centre; Institute of Cancer Sciences; University of Manchester; Manchester, UK.
authors.forename: Anthony
authors.initials: A
authors.lastname: Howell
authors.affiliation: Kimmel Cancer Center; Thomas Jefferson University; Philadelphia, PA USA.
authors.forename: Ubaldo E
authors.initials: UE
authors.lastname: Martinez-Outschoorn
authors.affiliation: Breakthrough Breast Cancer Research Unit and the Manchester Breast Centre; Institute of Cancer Sciences; University of Manchester; Manchester, UK; Manchester Centre for Cellular Metabolism (MCCM); University of Manchester; Manchester, UK.
authors.forename: Federica
authors.initials: F
authors.lastname: Sotgia
mesh_terms: D000071060:Breast Density; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D005260:Female; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology; D005355:Fibrosis / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007249:Inflammation / Q000378:metabolism / Q000473:pathology; D042361:Mammary Glands, Human / Q000002:abnormalities* / Q000378:metabolism / Q000473:pathology; D048055:Mitogen-Activated Protein Kinase 8 / Q000235:genetics / Q000378:metabolism*; D014411:Neoplastic Stem Cells / Q000378:metabolism* / Q000473:pathology; D015398:Signal Transduction; D059467:Transcriptome; D059016:Tumor Microenvironment / Q000235:genetics
chemical_list: D048055:Mitogen-Activated Protein Kinase 8
keywords: EGF; FGF; JNK; PDGF; SAPK; TGF-beta; breast cancer; cancer associated fibroblasts; fibrosis; gene signature; inflammation; mammographic density; mammography; microenvironment; stress signaling; tumor stroma; wound healing