Thrombin Inhibitor, Argatroban, Prevents Tumor Cell Migration and Bone Metastasis

Abstract

It is well known that malignant cells show procoagulant activity, which is associated with their metastatic potential. Thrombin, the key enzyme of the blood coagulation system, is generated around tumor cells, promoting the migration and metastasis of tumor cells. In this study, we evaluated the effect of argatroban, a specific thrombin inhibitor, on the migration and metastasis of B16BL6 melanoma cells. In vitro argatroban dose-dependently inhibited cell migration, the maximum inhibition being observed in the presence of 10 µM argatroban (p < 0.0001). In order to investigate the antimetastatic effect of the thrombin inhibitor, we used an animal model that we have reported previously. C57BL6 mice which had received a bone (femur or tibia) transplanted into the dorsal subcutis were injected with B16 melanoma cells into the left heart ventricle. Intraperitoneal injection of argatroban (9 mg/kg/day for 4 weeks) significantly reduced the number of limbs with metastatic lesions as compared to a placebo (p < 0.05). These results suggest that argatroban was associated with reduced melanoma metastases by inhibiting cell migration. Our results showed that argatroban is effective for treatment of bone metastasis.

The thrombin inhibitor Argatroban reduces breast cancer malignancy and metastasis via osteopontin-dependent and osteopontin-independent mechanisms

“…Argatroban was used at concentrations of 25 lg/ml (*50 lM) for all in vitro assays (cell growth, colony-forming ability, apoptosis, adhesion, migration) and 9 mg/kg/day for all in vivo animal studies. These doses were chosen based on previous studies by Asanuma et al [10] that demonstrated maximal inhibition of in vitro B16 mouse melanoma cell migration in the range of 10-100 lM, and inhibition of bone metastasis in vivo using a dose of 9 mg/kg/day [10].…”

“…Argatroban (9 mg/kg/day; treated groups) or saline (untreated groups) was administered subcutaneously starting 10 days after tumor cell injection for the duration of the experiment. This dose regimen was chosen based on a previous study which demonstrated an effect on experimental metastasis of B16F10 mouse melanoma following intracardiac cell injection [10]. Primary tumor growth was evaluated weekly by caliper measurement in two perpendicular dimensions, and tumor volume was estimated using the following formula: [volume = 0.52 9 (width) 2 9 (length)] for approximating the volume (mm 3 ) of an ellipsoid.…”

“…From a therapeutic perspective, there are several clinically available agents that can inhibit thrombin, including the broad-spectrum anticoagulants heparin and warfarin, and the thrombinspecific inhibitors hirudin, Refludan, Desirudin, and Argatroban [8,9]. Although some of these therapeutics have been demonstrated to have an inhibitory effect on malignant and metastatic behavior in experimental studies [10][11][12][13][14], their main clinical application has been for management of coagulation disorders/complications rather than for prevention of cancer progression [8,9].…”

Stress repair mechanism activity explains inflammation and apoptosis

“…Malignancy is an abnormal manifestation of tissue repair activity that occurs when prolonged and exaggerated positive feedback causes SRM repair hyperactivity to become selfsustaining [204,210,593]. Malignant cells invade normal tissues, release tissue factor, activate nervous sensors, and cause a "vicious cycle" of positive feedback that sustains abnormal thrombin elevations that inhibit the apoptosis and resolution that normally occurs at the conclusion of the tissue repair process [29,82,216,217,[594][595][596][597]. For example, uncontrolled osteomyelitis sometimes evolves into osteosarcoma.…”

Emerging Applications of Argatroban in the Management of Systemic Malignancies

“…Similarly, argatroban attenuates metastasis in melanomas. 8 These effects are dose-dependent. Interestingly, argatroban also attenuates ischemia/ reperfusion-induced liver metastasis from colon carcinomas.…”