Cancer enhances the risk of venous thromboembolism, but a hypercoagulant microenvironment also promotes cancer progression. Although anticoagulants have been suggested as a potential anticancer... Show moreCancer enhances the risk of venous thromboembolism, but a hypercoagulant microenvironment also promotes cancer progression. Although anticoagulants have been suggested as a potential anticancer treatment, clinical studies on the effect of such modalities on cancer progression have not yet been successful for unknown reasons. In normal physiology, complex formation between the subendothelial-expressed tissue factor (TF) and the blood-borne liver-derived factor VII (FVII) results in induction of the extrinsic coagulation cascade and intracellular signaling via protease-activated receptors (PARs). In cancer, TF is overexpressed and linked to poor prognosis. Here, we report that increased levels of FVII are also observed in breast cancer specimens and are associated with tumor progression and metastasis to the liver. In breast cancer cell lines, tumor-expressed FVII drives changes reminiscent of epithelial-to-mesenchymal transition (EMT), tumor cell invasion, and expression of the prometastatic genes, SNAI2 and SOX9. In vivo, tumorexpressed FVII enhanced tumor growth and liver metastasis. Surprisingly, liver-derived FVII appeared to inhibit metastasis. Finally, tumor-expressed FVII-induced prometastatic gene expression independent of TF but required a functional endothelial protein C receptor, whereas recombinant activated FVII acting via the canonical TF:PAR2 pathway inhibited prometastatic gene expression. Here, we propose that tumor-expressed FVII and liverderived FVII have opposing effects on EMT and metastasis. Show less
Tissue Factor (TF) is a membrane protein that is responsible for the initiation of the coagulation. In addition to its coagulant activity, it can also signal through a member of G-protein coupled... Show moreTissue Factor (TF) is a membrane protein that is responsible for the initiation of the coagulation. In addition to its coagulant activity, it can also signal through a member of G-protein coupled receptor family, PARs, thus play a role in breast cancer growth and angiogenesis. The switch between signaling and coagulant TF regulated by the oxidation/reduction of an allosteric disulfide bond which resides in TF antigen. A decade ago, it was discovered that TF RNA can be alternatively spliced to form a soluble protein called Alternatively Spliced Tissue Factor (asTF). This protein is non-coagulant. However, it plays a major role in breast cancer growth via inducing cancer cell proliferation. The mechanism lying behind behind this phenomenon is asTF's capability to ligate integrins thus it can initiate integrin signaling. Moreover, both TF and asTF can synergize with estrogen pathway thus providing a complex regulation of breast cancer progression. Show less
