Recombinant thrombomodulin suppresses tumor growth of pancreatic cancer by blocking thrombin-induced PAR1 and NF-κB activation

Background. Thrombomodulin, an anticoagulant that inhibits thrombin-induced growth factor promotion, also has an anti-inflammatory effect. Furthermore, thrombomodulin inhibits nuclear factor kappa B activation, which plays a crucial role in cancer progression. We assessed the antitumor activity of recombinant thrombomodulin for pancreatic cancer. Methods. A xenograft orthotopic model was established in mice by implantation of human pancreatic cancer cells. The animals were treated with intraperitoneal injection of recombinant thrombomodulin 5 times a week for 4 weeks. Nuclear factor-kappa B activation was evaluated by measuring nuclear localization of the p65.. Efficacy of recombinant thrombomodulin on the signal transduction of nuclear factor-kappa B was measured in vitro under preconditioning with thrombin or epidermal growth factor. Results. Tumor growth was suppressed by recombinant thrombomodulin (P < .05). Recombinant thrombomodulin inhibited the expression of I kappa B kinase beta (P <.05) and pI kappa B alpha (P < .01), as well as the activation of nuclear factor-kappa B NF-kappa B (P < .001). Furthermore, recombinant thrombomodulin inhibited thrombin-induced protease activate receptor 1 and nuclear factor-kappa B activation in vitro (P < .05). The number of Ki67-positive cells was decreased by recombinant thrombomodulin (P < .01). Recombinant thrombomodulin also suppressed body weight loss associated with pancreatic cancer (P < .05). No obvious adverse effects were observed. Conclusion. Recombinant thrombomodulin significantly suppressed tumor growth against human pancreatic cancer by blocking thrombin-induced nuclear factor-kappa B activation without adverse effects.