title: A novel role of thrombospondin-1 in cervical carcinogenesis: inhibit stroma reaction by inhibiting activated fibroblasts from invading cancer.
abstract: Thrombospondin (TSP)-1, a potent angiogenesis inhibitor, has been shown to exert different biological functions on various cell types. Here, we investigate the role of TSP-1 in tumor-stroma reaction, which is mainly characterized by fibroblast activation to create a permissive microenvironment for tumor progression. Immunohistochemistry examinations in the human surgical specimens have shown that a downregulation of TSP-1 during the progression of cervical carcinogenesis was accompanied by an emergence in the upregulation of stroma markers, alpha-smooth muscle actin (alpha-SMA) and desmin. Transfection of SiHa cervical cancer cells with a plasmid expressing the TSP-1 protein exhibited antiangiogenic activity in vitro and resulted in reduced tumor growth in severe combined immunodeficiency (SCID) mice, which was accompanied by a decrease in tumor vascularization and lower expressions of alpha-SMA and desmin than those in the vector controls. Transfection with TSP-1 and purified TSP-1 added to NIH3T3 cells did not alter the protein levels of alpha-SMA and desmin but significantly inhibited matrix metalloprotease-2 activity. Transforming growth factor-beta (TGF-beta), a major factor in the activation of fibroblasts, increased alpha-SMA and desmin expression and the ability of cell migration and invasion in NIH3T3 cells. The increased migration ability and the invasive ability into tumor cluster of TGF-beta-treated NIH3T3 cells were dose dependently inhibited by TSP-1. In contrast, ectopic TSP-1 expression in SiHa cells has little effect on the invasive ability of the NIH3T3 cells. Together, our findings demonstrate a novel role of TSP-1 to inhibit tumor-stroma reaction that could be attributed to the blockage of activated fibroblasts from invading cancer cells.
authors.affiliation: Department of Obstetrics and Gynecology, Chi Mei Foundation Hospital, Tainan 710, Taiwan.
authors.forename: Ming-Ping
authors.initials: MP
authors.lastname: Wu
authors.forename: Ming-Jer
authors.initials: MJ
authors.lastname: Young
authors.forename: Ching-Cherng
authors.initials: CC
authors.lastname: Tzeng
authors.forename: Chii-Ruey
authors.initials: CR
authors.lastname: Tzeng
authors.forename: Kuo-Feng
authors.initials: KF
authors.lastname: Huang
authors.forename: Li-Wha
authors.initials: LW
authors.lastname: Wu
authors.forename: Cheng-Yang
authors.initials: CY
authors.lastname: Chou
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D002465:Cell Movement / Q000502:physiology; D002478:Cells, Cultured; D003893:Desmin / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D051379:Mice; D009361:Neoplasm Invasiveness / Q000473:pathology*; D009389:Neovascularization, Pathologic / Q000378:metabolism / Q000473:pathology; D019700:Thrombospondin 1 / Q000378:metabolism*; D014162:Transfection; D002583:Uterine Cervical Neoplasms / Q000378:metabolism / Q000473:pathology*
chemical_list: D000199:Actins; D003893:Desmin; D019700:Thrombospondin 1; D020778:Matrix Metalloproteinase 2