title: Identification of colonic fibroblast secretomes reveals secretory factors regulating colon cancer cell proliferation.
abstract: Stromal microenvironment influences tumor cell proliferation and migration. Fibroblasts represent the most abundant stromal constituents. Here, we established two pairs of normal fibroblast (NF) and cancer-associated fibroblast (CAF) cultures from colorectal adenocarcinoma tissues and the normal counterparts. The NFs and CAFs were stained positive for typical fibroblast markers and inhibited colon cancer (CC) cell proliferation in in vitro cocultures and in xenograft mouse models. The fibroblast conditioned media were analyzed using LC-MS and 227 proteins were identified at a false discovery rate of 1.3%, including 131 putative secretory and 20 plasma membrane proteins. These proteins were enriched for functional categories of extracellular matrix, adhesion, cell motion, inflammatory response, redox homeostasis and peptidase inhibitor. Secreted protein acidic and rich in cysteine, transgelin, follistatin-related protein 1 (FSTL1) and decorin was abundant in the fibroblast secretome as confirmed by Western blot. Silencing of FSTL1 and transgelin in colonic fibroblast cell line CCD-18Co induced an accelerated proliferation of CC cells in cocultures. Exogenous FSTL1 attenuates CC cell proliferation in a negative fashion. FSTL1 was upregulated in CC patient plasma and cancerous tissues but had no implication in prognosis. Our results provided novel insights into the molecular signatures and modulatory role of CC associated fibroblasts.
  
  
  CONCLUSIONS
  In this study, a label-free LC-MS was performed to analyze the secretomes of two paired primary fibroblasts, which were isolated from fresh surgical specimen of colorectal adenocarcinoma and adjacent normal colonic tissues and exhibited negative modulatory activity for colon cancer cell growth in in vitro cocultures and in vivo xenograph mouse models. Follistatin-related protein 1 was further revealed to be one of the stroma-derived factors of potential suppression role for colon cancer cell proliferation. Our results provide novel insights into the molecular signatures and the modulatory role of colon cancer associated fibroblasts, and establish a valuable resource for the development of therapeutic agents or novel clinic biomarker.
authors.affiliation: Department of Medical Systems Biology of School of Basic Medical Sciences and Institutes of Biomedical Sciences, Fudan University, 131 Dongan Road, Shanghai 200032, China.
authors.forename: Sun-Xia
authors.initials: SX
authors.lastname: Chen
authors.affiliation: Department of Medical Systems Biology of School of Basic Medical Sciences and Institutes of Biomedical Sciences, Fudan University, 131 Dongan Road, Shanghai 200032, China.
authors.forename: Xiao-En
authors.initials: XE
authors.lastname: Xu
authors.affiliation: Department of Medical Systems Biology of School of Basic Medical Sciences and Institutes of Biomedical Sciences, Fudan University, 131 Dongan Road, Shanghai 200032, China; Department of Chemistry, Fudan University, 220 Handan Road, Shanghai 200433, China.
authors.forename: Xiao-Qing
authors.initials: XQ
authors.lastname: Wang
authors.affiliation: College of Bioscience and Biotechnology, Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Yangzhou University, Yangzhou 225009, China.
authors.forename: Shu-Jian
authors.initials: SJ
authors.lastname: Cui
authors.affiliation: Department of Medical Systems Biology of School of Basic Medical Sciences and Institutes of Biomedical Sciences, Fudan University, 131 Dongan Road, Shanghai 200032, China.
authors.forename: Lei-Lei
authors.initials: LL
authors.lastname: Xu
authors.affiliation: Department of Medical Systems Biology of School of Basic Medical Sciences and Institutes of Biomedical Sciences, Fudan University, 131 Dongan Road, Shanghai 200032, China.
authors.forename: Ying-Hua
authors.initials: YH
authors.lastname: Jiang
authors.affiliation: Department of Medical Systems Biology of School of Basic Medical Sciences and Institutes of Biomedical Sciences, Fudan University, 131 Dongan Road, Shanghai 200032, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Medical Systems Biology of School of Basic Medical Sciences and Institutes of Biomedical Sciences, Fudan University, 131 Dongan Road, Shanghai 200032, China.
authors.forename: Hai-Bo
authors.initials: HB
authors.lastname: Yan
authors.affiliation: Department of Medical Systems Biology of School of Basic Medical Sciences and Institutes of Biomedical Sciences, Fudan University, 131 Dongan Road, Shanghai 200032, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Medical Systems Biology of School of Basic Medical Sciences and Institutes of Biomedical Sciences, Fudan University, 131 Dongan Road, Shanghai 200032, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Qiao
authors.affiliation: Department of Medical Systems Biology of School of Basic Medical Sciences and Institutes of Biomedical Sciences, Fudan University, 131 Dongan Road, Shanghai 200032, China; Department of Chemistry, Fudan University, 220 Handan Road, Shanghai 200433, China. Electronic address: pyyang@fudan.edu.cn.
authors.forename: Peng-Yuan
authors.initials: PY
authors.lastname: Yang
authors.affiliation: Department of Medical Systems Biology of School of Basic Medical Sciences and Institutes of Biomedical Sciences, Fudan University, 131 Dongan Road, Shanghai 200032, China. Electronic address: liuf@fudan.edu.cn.
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
mesh_terms: D049109:Cell Proliferation; D003106:Colon / Q000378:metabolism* / Q000473:pathology; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000473:pathology*; D005347:Fibroblasts / Q000378:metabolism* / Q000473:pathology; D055442:Metabolome; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000737:chemistry / Q000378:metabolism*; D020543:Proteome / Q000737:chemistry / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D059016:Tumor Microenvironment
chemical_list: D009363:Neoplasm Proteins; D020543:Proteome
keywords: Cancer-associated fibroblast; Colorectal cancer; Follistatin-related protein 1; Proteomics; Secretome; Tumor microenvironment