title: Identification and quantification of proteins differentially secreted by a pair of normal and malignant breast-cancer cell lines.
abstract: Secreted proteins play a pivotal role in cellular functions. To better understand malignant behavior, we adapted stable isotopic labeling with amino acids in cell culture technology to identify and quantify proteins differentially released into the extracellular media by a pair of normal and malignant breast-cancer cell lines. Approximately 380 non-redundant proteins were quantified in serum-free media. Of the assigned proteins, 62% are classified secreted in protein databases and an additional 25% are designated secreted in the literature. A number of growth factors were found differentially regulated. Tumor necrosis factor, pigment epithelial-differentiating factor and stem-cell growth factor precursor showed decreased expression in breast-cancer cell line, whereas Inhibin beta and macrophage migration inhibitory factor show increased expression. Interestingly, protease inhibitors, including plasma protease (C1) inhibitor, PZP precursor, and SerpinE2 were significantly down-regulated in cancer cell line as were angiostatic factors from extracellular matrix (ECM) such as endorepillin. Further, the C-terminal fragment of type XVIII collagen, endostatin, a potent angiostatic factor, was down-regulated as well whereas extracellular collagens and osteoblast-specific factor 2 (OSF-2), were up-regulated. Differential expression and secretion of SerpinE2 and OSF-2 were confirmed using Western blotting. These results corroborate models of invasive tumors sustained by elaborate coordination of stromal cells via chemokines and growth factors, while protease inhibitors remodel the ECM to stimulate angiogenesis.
authors.affiliation: Invitrogen Corporation, Carlsbad, CA 92008, USA. xiquan.liang@invitrogen.com
authors.forename: Xiquan
authors.initials: X
authors.lastname: Liang
authors.forename: Jarkko
authors.initials: J
authors.lastname: Huuskonen
authors.forename: Mahbod
authors.initials: M
authors.lastname: Hajivandi
authors.forename: Raul
authors.initials: R
authors.lastname: Manzanedo
authors.forename: Paul
authors.initials: P
authors.lastname: Predki
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Amshey
authors.forename: R Marshall
authors.initials: RM
authors.lastname: Pope
mesh_terms: D000596:Amino Acids / Q000737:chemistry / Q000378:metabolism; D015415:Biomarkers / Q000032:analysis; D001943:Breast Neoplasms / Q000737:chemistry* / Q000175:diagnosis; D018929:Cell Culture Techniques; D002460:Cell Line; D045744:Cell Line, Tumor; D016207:Cytokines / Q000032:analysis; D005109:Extracellular Matrix / Q000737:chemistry; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000032:analysis; D011506:Proteins / Q000032:analysis* / Q000378:metabolism; D015203:Reproducibility of Results; D015842:Serine Proteinase Inhibitors / Q000032:analysis
chemical_list: D000596:Amino Acids; D015415:Biomarkers; D016207:Cytokines; D036341:Intercellular Signaling Peptides and Proteins; D011506:Proteins; D015842:Serine Proteinase Inhibitors