Activated protein C enhances cell motility of endothelial cells and MDA-MB-231 breast cancer cells by intracellular signal transduction

Abstract

Activated protein C (APC), an anticoagulant serine protease, has been shown to have non-hemostatic functions related to inflammation, cell survival, and cell migration. In this study we investigate the mechanism by which APC promotes angiogenesis and breast cancer invasion using ex vivo and in vitro methods. When proteolytically active, APC promotes cell motility/invasion and tube formation of endothelial cells. Ex vivo aortic ring assays verify the role of APC in promoting angiogenesis, which was determined to be dependent on EGFR and MMP activation. Given the capacity of APC to promote angiogenesis and the importance of this process in cancer pathology, we investigated whether the mechanisms by which APC promotes angiogenesis can also promote motility and invasion in the MDA-MB-231 breast cancer cell line. Our results indicate that, extracellularly, APC engages EPCR, PAR-1, and EGFR in order to increase the invasiveness of MDA-MB-231 cells. APC activation of matrix metalloprotease (MMP) -2 and/or -9 is necessary but not sufficient to increase invasion, and APC does not utilize the endogenous plasminogen activation system to increase invasion. Intracellularly, APC activates ERK, Akt, and NFκB, but not the JNK pathway to promote MDA-MB-231 cell motility. Similar to the hemostatic protease thrombin, APC has the ability to enhance both endothelial cell motility/angiogenesis and breast cancer cell migration.

Endothelial cell protein C receptor: a multiliganded and multifunctional receptor

“…However, EPCR-mediated cell signaling in a tumor cell may promote cancer cell migration, invasion, and angiogenesis and inhibit cancer cell apoptosis. [73][74][75][76] Data from recent studies reflect these opposing effects of EPCR in cancer.…”

Endothelial Cell Protein C Receptor Opposes Mesothelioma Growth Driven by Tissue Factor

“…Disse et al reported that EPCR promoted PAR1 and PAR2 cleavage by FXa in the ternary complex of TF-FVIIa-FXa (24). Studies in cell model systems implicated that EPCR may promote tumor metastasis as EPCR-APC-mediated PAR1 signaling was shown to promote cancer cell migration, invasion, and angiogenesis (25, 26). In vivo studies gave conflicting data as EPCR-APC signaling decreased lung metastasis in melanoma model by preventing tumor cell migration through enhancement of endothelial barrier function (27, 28), whereas EPCR over expression increased metastasis in lung adenocarcinoma by promoting tumor cell survival (29).…”

Receptor of Activated Protein C Promotes Metastasis and Correlates with Clinical Outcome in Lung Adenocarcinoma

“…Although EPCR is expressed in a variety of human tumors, including breast, lung, glioblastoma, and erythroleukemia (20,21), the effects of APC binding to EPCR remain ill defined (22,23).…”