Tumor-expressed factor VII is associated with survival and regulates tumor progression in breast cancer

Cancer 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, tumor-expressed 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 liver-derived FVII have opposing effects on EMT and metastasis.