Autophagy has an important role in tumor biology of hepatocellular carcinoma (HCC). Recent studies demonstrated that tissue factor (TF) combined with coagulation factor VII (FVII) has a pathological role by activating a G-protein-coupled receptor called protease-activated receptor 2 (PAR2) for tumor growth. The present study aimed to investigate the interactions of autophagy and the coagulation cascade in HCC. Seventy HCC patients who underwent curative liver resection were recruited. Immunohistochemical staining and western blotting were performed to determine TF, FVII, PAR2 and light chain 3 (LC3A/B) expressions in tumors and their contiguous normal regions. We found that the levels of autophagic marker LC3A/B-II and coagulation proteins (TF, FVII and PAR2) were inversely correlated in human HCC tissues. Treatments with TF, FVII or PAR2 agonist downregulated LC3A/B-II with an increased level of mTOR in Hep3B cells; in contrast, knockdown of TF, FVII or PAR2 increased LC3A/B. Furthermore, mTOR silencing restored the impaired expression of LC3A/B-II in TF-, FVII- or PAR2-treated Hep3B cells and activated autophagy. Last, as an in vivo correlate, we administered TF, FVII or PAR2 agonist in a NOD/severe combined immunodeficiency xenograft model and showed decreased LC3A/B protein levels in HepG2 tumors with treatments. Overall, our present study demonstrated that TF, FVII and PAR2 regulated autophagy mainly via mTOR signaling. The interaction of coagulation and autophagic pathways may provide potential targets for further therapeutic application in HCC.

We previously demonstrated PAR2 starts upstreamed with tissue factor (TF) and factor VII (FVII), inhibited autophagy via mTOR signaling in HCC. However, the mechanism underlying for merging functions of PAR2 with the coagulation system in HCC progression remained unclear. The present study aimed to investigate the role of TF, FVII and PAR2 in tumor progression of HCC. The expressions of TF, FVII and PAR2 from HCC specimens were evaluated by immunohistochemical stains and western blotting. We found that the expression of FVII, but not TF and PAR2, directly related to the vascular invasion and the clinical staging. Importantly, a lower level of FVII expression was significantly associated with the longer disease-free survival. The addition of FVII but not TF induced the expression of PAR2 and phosphorylation of ERK1/2, whereas knockdown of FVII decreased PAR2 expression and ERK1/2 phosphorylation in HCC cell lines. Furthermore, levels of phosphor-TSC2 (Ser664) were increased after treatment with FVII and PAR2 agonist whereas these were significantly abolished in the presence of a potent and specific MEK/ERK inhibitor U0126. Moreover, mTOR knockdown highly reduced Hep3B migration, which could be reverted by FVII but not TF and PAR2. These results indicated that FVII/PAR2 signaling through MEK/ERK and TSC2 axis for mTOR activation has potent effects on the migration of HCC cells. In addition, FVII/PAR2 signaling elicits an mTOR-independent signaling, which promotes hepatoma cell migration in consistent with the clinical observations. Our study indicates that levels of FVII, but not TF, are associated with tumor migration and invasiveness in HCC, and provides clues that evaluation of FVII expression in HCC may be useful as a prognostic indicator in patients with HCC and may form an alternative target for further therapy.