Thrombin enhances glioma growth.

Background: Our previous studies have demonstrated that argatroban, a specific thrombin inhibitor, reduces brain edema and neurological deficits in rat glioma models. The present study investigated whether or not thrombin enhances glioma growth in vivo and in vitro.

Methods: There were two parts in this study. In the first part, rat C6 glioma cells were treated with or without thrombin. These cells were then injected into the right caudate of adult male Fischer 344 rats. Rats underwent behavioral testing prior to sacrifice 12 days later for tumor mass measurement. In the second part, C6 cells were incubated in serum-free medium for 24 hours and then treated with thrombin with or without argatroban, a thrombin inhibitor. DNA synthesis was examined using a 5-bromo-2'-deoxyuridine (BrdU) ELISA kit. Cell proliferation was determined using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay.

Findings: Treatment of C6 cells with thrombin prior to intracerebral implantation resulted in a larger tumor mass and worse neurological deficits at dayl2. In vitro, thrombin increased DNA synthesis in C6 glioma cells, and this effect was blocked by argatroban. MTT assay showed that thrombin significantly increased glioma cell proliferation in vitro.

Conclusions: In summary, thrombin enhances C6 glioma growth in vivo and cell proliferation in vitro suggesting that thrombin may be a target of glioma therapy.