title: Secretion of pleiotrophin stimulates breast cancer progression through remodeling of the tumor microenvironment.
abstract: Pleiotrophin (PTN, Ptn) is an 18-kDa secretory cytokine expressed in many breast cancers; however, the significance of Ptn expression in breast cancer has not been established. We have now tested three models to determine the role of inappropriate expression of Ptn in breast cancer. Mouse mammary tumor virus (MMTV) promoter-driven Ptn expressed in MMTV-polyoma virus middle T antigen (PyMT)-Ptn mouse breast cancers was first shown to induce rapid growth of morphologically identified foci of "scirrhous" carcinoma and to extensively remodel the microenvironment, including increased tumor angiogenesis and striking increases in mouse protocollagens Ialpha2, IValpha5, and XIalpha1, and elastin. Ectopic Ptn expression in MCF-7 (human breast cancer)-Ptn cell xenografts also was shown to markedly increase MCF-7-Ptn cell xenograft growth in nude mice; furthermore, it induced extensive remodeling of the microenvironment and tumor angiogenesis. In a coculture model of equal numbers of NIH 3T3 stromal fibroblasts and MCF-7-Ptn cells, PTN secreted from MCF-7-Ptn cells was then shown to induce a more malignant MCF-7-Ptn breast cancer cell phenotype and extensive remodeling of the MCF-7-Ptn/NIH 3T3 cell microenvironment; it up-regulated expression of markers of aggressive breast cancers, including PKCdelta and matrix metalloproteinase-9 in both MCF-7-Ptn and NIH 3T3 cells. The morphological phenotypes of MCF-7-Ptn cell xenografts and MCF-7-Ptn cell/NIH 3T3 cell cocultures closely resembled breast cancers in MMTV-PyMT-Ptn mice. Inappropriate expression of Ptn thus promotes breast cancer progression in mice; the data suggest that secretion of PTN through stimulation of the stromal cell microenvironment alone may be sufficient to account for significant features of breast cancer progression.
authors.affiliation: Department of Molecular and Experimental Medicine and Cell Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
authors.forename: Yunchao
authors.initials: Y
authors.lastname: Chang
authors.forename: Masahiko
authors.initials: M
authors.lastname: Zuka
authors.forename: Pablo
authors.initials: P
authors.lastname: Perez-Pinera
authors.forename: Aurora
authors.initials: A
authors.lastname: Astudillo
authors.forename: Joanne
authors.initials: J
authors.lastname: Mortimer
authors.forename: James R
authors.initials: JR
authors.lastname: Berenson
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Deuel
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000209:etiology / Q000378:metabolism* / Q000473:pathology*; D002352:Carrier Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D018920:Coculture Techniques; D016207:Cytokines / Q000378:metabolism*; D018450:Disease Progression; D005260:Female; D006133:Growth Substances; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D041681:NIH 3T3 Cells; D009385:Neoplastic Processes; D019899:Paracrine Communication; D017154:Stromal Cells; D014183:Transplantation, Heterologous
chemical_list: D002352:Carrier Proteins; D016207:Cytokines; D006133:Growth Substances; C066845:pleiotrophin