title: Formation of tissue factor-factor VIIa-factor Xa complex prevents apoptosis in human breast cancer cells.
abstract: Tissue factor (TF) is a transmembrane glycoprotein that initiates blood coagulation when complexed with factor VIIa (FVIIa). TF is constitutively expressed in a variety of tumor cells and has been shown to play a role in cellular signaling and tumor progression. In this study, we investigated the effect of TF-FVIIa mediated signaling on apoptosis in human breast cancer cells. Apoptosis was induced by prolonged serum starvation and studied using the Adr-MCF-7 cell line, which has high endogenous TF expression. Treatment of the cells with the combination of FVIIa (10 nM) and FX (150 nM), reduced apoptosis by nearly 50% compared with untreated, control cells using an ELISA that detects histone-DNA fragments. In contrast, FVIIa (10 nM) alone did not significantly prevent apoptosis. Pretreatment of the Adr-MCF-7 cells with hirudin, a specific thrombin inhibitor, did not inhibit the anti-apoptotic effect of the combination of FVIIa and FX, whereas this effect could be abrogated by inhibition of phosphorylation of either p44/42 mitogen-activated protein kinase (MAPK) or protein kinase B (PKB/Akt). In addition, treatment of the Adr-MCF-7 cells with the combination of FVIIa and FX led to a 30-50% increase in the level of the anti-apoptotic protein, survivin, compared with untreated cells using Western blot analysis. These results indicate that formation of TF-FVIIa-FXa complex prevents apoptosis in breast cancer cells by a thrombin-independent pathway. Moreover, the anti-apoptotic effect of this signaling pathway involves phosphorylation of both p44/42 MAPK and PKB/Akt and might be mediated in part by an increase in cell survivin levels.
authors.affiliation: Temple University School of Medicine, Sol Sherry Thrombosis Research Center, Philadelphia, PA 19140, USA.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Jiang
authors.forename: Yan Lin
authors.initials: YL
authors.lastname: Guo
authors.forename: Michael E
authors.initials: ME
authors.lastname: Bromberg
mesh_terms: D017209:Apoptosis; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000737:chemistry / Q000378:metabolism*; D053148:Caspase 3 / Q000378:metabolism; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival; D053938:DNA Fragmentation; D004789:Enzyme Activation; D004797:Enzyme-Linked Immunosorbent Assay; D015942:Factor VIIa / Q000737:chemistry* / Q000378:metabolism; D015951:Factor Xa / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D010766:Phosphorylation; D011994:Recombinant Proteins / Q000737:chemistry; D013925:Thromboplastin / Q000737:chemistry* / Q000378:metabolism; D013997:Time Factors
chemical_list: D011994:Recombinant Proteins; D013925:Thromboplastin; D015942:Factor VIIa; D015951:Factor Xa; D053148:Caspase 3; D020169:Caspases