Project description:Background: The terminal duct lobular unit (TDLU) is the most dynamic structure in the human breast and the putative site of origin of human breast cancer. Although stromal cells contribute to a specialized microenvironment in many organs, this component remains largely understudied in the human breast. We here demonstrate the impact on epithelium of two lineages of breast stromal fibroblasts, one of which accumulates in the TDLU while the other resides outside the TDLU in the interlobular stroma. Methods: The two lineages are prospectively isolated by FACS based on different expression levels of CD105 and CD26. The characteristics of the two fibroblast lineages are assessed by immunocytochemical staining and gene expression analysis. The differentiation capacity of the two fibroblast populations is determined by exposure to specific differentiating conditions followed by analysis of adipogenic and osteogenic differentiation. To test whether the two fibroblast lineages are functionally imprinted by their site of origin, single cell sorted CD271low/MUC1high normal breast luminal epithelial cells are plated on fibroblast feeders for the observation of morphological development. Epithelial structure formation and polarization is shown by immunofluorescence and digitalized quantification of immunoperoxidase stained cultures. Results: Lobular fibroblasts are CD105high/CD26low while interlobular fibroblasts are CD105low/CD26high. Once isolated the two lineages remain phenotypically stable and functionally distinct in culture. Lobular fibroblasts have properties in common with bone marrow derived mesenchymal stem cells and they specifically convey growth and branching morphogenesis of epithelial progenitors. Conclusions: Two distinct functionally specialized fibroblast lineages exist in the normal human breast, of which the lobular fibroblasts have properties in common with mesenchymal stem cells and support epithelial growth and morphogenesis. We propose that lobular fibroblasts constitute a specialized microenvironment for human breast luminal epithelial progenitors, i.e. the putative precursors of breast cancer.
Project description:How organ-specific metastatic traits accumulate in primary tumors remains unknown. We identified a role of the primary tumor stroma in selecting breast cancer cells that are primed for metastasis in the bone. A fibroblast-rich stroma in breast tumors creates a microenvironment that is similar to that of bone metastases in its abundance of the cytokines CXCL12 and IGF1. Heterogeneous breast cancer cell populations growing in such mesenchymal environment evolve towards a preponderance of clones that thrive on CXCL12 and IGF1. Fibroblast-driven selection of bone metastatic clones in mammary tumors is suppressed by CXCL12 and IGF1 receptor inhibition. Thus, a fibroblast-rich stroma in breast tumors can pre-select bone metastatic seeds, promoting the evolution of metastatic traits and the interplay between a primary tumor and its distant metastases.
Project description:Chronic obstructive pulmonary disease (COPD) is an independent risk factor for lung cancer, suggesting that COPD stroma favors cancer initiation. Therefore, we used proteomics and polysome-profiling to identify gene expression programs that distinguish stroma of patients harboring lung cancer from those that do not, with varied COPD severities. This profiling unveiled distinct COPD-dependent cancer-associated gene expression programs predominantly manifesting as alterations in mRNA translation. Mechanistically, such programs are downstream of the mammalian target of rapamycin pathway in mild COPD and pathological extracellular matrix in more severe COPD; and both programs parallel activation of distinct pro-cancer fibroblast-derived secretomes. Therefore, depending upon COPD severity, the lung stroma can exist in two states favoring cancer initiation, which likely result in distinct disease entities.
Project description:How organ-specific metastatic traits accumulate in primary tumors remains unknown. We identified a role of the primary tumor stroma in selecting breast cancer cells that are primed for metastasis in the bone. A fibroblast-rich stroma in breast tumors creates a microenvironment that is similar to that of bone metastases in its abundance of the cytokines CXCL12 and IGF1. Heterogeneous breast cancer cell populations growing in such mesenchymal environment evolve towards a preponderance of clones that thrive on CXCL12 and IGF1. Fibroblast-driven selection of bone metastatic clones in mammary tumors is suppressed by CXCL12 and IGF1 receptor inhibition. Thus, a fibroblast-rich stroma in breast tumors can pre-select bone metastatic seeds, promoting the evolution of metastatic traits and the interplay between a primary tumor and its distant metastases. Affymetrix U133 Plus2 arrays were hybridized according to the manufacturer's procedure using RNA extracted from 47 primary breast tumors. Specific gene sets were evaluated in this cohort.
Project description:Pancreatic cancer is characterized by abundant desmoplastic stroma. Despite numerous theoretical and experimental efforts, therapeutic approaches targeting pancreatic cancer stroma have been largely unsuccessful, highlighting the need for more comprehensive assessment of inter- and intratumoral stromal heterogeneity in a large series of clinical tumors. Quantitative computation of FAP-dominant fibroblasts, ACTA2-dominant fibroblasts, and intratumoral collagen in whole-tissue sections from 215 treatment-naïve pancreatic cancers allowed us to identify three distinct stroma types (FAP-dominant fibroblast-rich stroma [F-stroma], ACTA2-dominant fibroblast-rich stroma [A-stroma], and collgen-rich stroma [C-stroma]), which were differentially associated with patient outcomes, molecular characteristics and the immunosuppressive tumor microenvironment. We explored differentially expressed genes between three distinct stroma types (F-stroma, A-stroma, and C-stroma) using frozen samples from 20 patients with pancreatic cancer.
Project description:Cancer cells interact with surrounding stromal fibroblasts during tumorigenesis, but the complex molecular rules that govern these interactions remain poorly understood, thus hindering the development of therapeutic strategies to target cancer stroma. We have taken a mathematical approach to begin defining these rules by performing large-scale quantitative analysis of fibroblast effects on cancer cell proliferation across more than four hundred heterotypic cell line pairings. Systems-level modeling of this complex dataset using singular value decomposition revealed that normal tissue fibroblasts variably express at least two functionally distinct activities, one which reflects transcriptional programs associated with activated mesenchyme, that act either coordinately or at cross-purposes to modulate cancer cell proliferation. To gain insight into the molecular identity of these fibroblast activities, we isolated RNA from 36 human skin and lung fibroblast cell line monocultures from Coriell Repositories or ATCC and performed microarray-based gene expression profiling using Affymetrix gene chips.