Collagen architecture in pregnancy-induced protection from breast cancer.

TitleCollagen architecture in pregnancy-induced protection from breast cancer.
Publication TypeJournal Article
Year of Publication2013
AuthorsMaller O, Hansen KC, Lyons TR, Acerbi I, Weaver VM, Prekeris R, Tan A-C, Schedin P
JournalJ Cell Sci
IssuePt 18
Date Published2013 Sep 15

The reduction in breast cancer risk attributed to early-age pregnancy is mediated in part by changes in the mammary epithelium. Here, we address the role of the mammary stroma in this protection. Utilizing tumor cells capable of transitioning from indolent to proliferative or invasive states, we demonstrate that mammary extracellular matrix (ECM) from parous rats (parous matrix) decreases tumor growth and impedes cellular phenotypes associated with tumor cell invasion compared with that observed using nulliparous matrix. Proteomic analysis identifies an increased abundance of collagen I in parous matrix, an observation extended to breast tissue of parous women. Given the pro-tumorigenic attributes of fibrillar collagen, these results were unexpected. Second-harmonic generation imaging and atomic force microscopy revealed that the abundant collagen observed in the mammary glands of parous rats is less linearized and associated with a decrease in stromal stiffness, implicating collagen organization and stiffness in parity-induced protection. Using 3D cell culture models, we demonstrate that linearized (fibrillar) collagen I induces cellular phenotypes consistent with an invasive behavior in mammary tumor cells and alters the subcellular distribution of β1 integrin. Conversely, high-density non-fibrillar collagen I induces tumor-suppressive attributes, including increases in junctional E-cadherin in tumor cells, upregulation of genes encoding components of cell-cell junctions, and downregulation of mesenchymal-specific and metalloproteinase-encoding genes. These data show that collagen organization, rather than density alone, is a key contributor to the invasive phenotype. Furthermore, our data show that parity alters the composition and organization of mammary ECM, particularly fibrillar collagen, in a manner consistent with tumor suppression.

Alternate JournalJ. Cell. Sci.
PubMed ID23843613
PubMed Central IDPMC3772386
Grant ListP30 CA046934 / CA / NCI NIH HHS / United States
R01 CA138818 / CA / NCI NIH HHS / United States
R01 CA138818-01A1 / CA / NCI NIH HHS / United States
R21CA132741 / CA / NCI NIH HHS / United States
U01 ES019458 / ES / NIEHS NIH HHS / United States
U01 ES019458 / ES / NIEHS NIH HHS / United States
UL1 RR025780 / RR / NCRR NIH HHS / United States