| Summary: | 碩士 === 國防醫學院 === 生物及解剖學研究所 === 101 === Glioma is the most malignant brain tumor with strong migration and invasion ability in CNS. Because of the ineffectiveness of traditional therapy, the average survival period is only about one year. Caffeine has been reported with its anticancer effects, including the suppression of cell proliferation and induction of invasion and apoptosis. However, whether caffeine can reduce the migration of rat C6 glioma and the signaling mechanism are still unclear. In this study, after treatment with 0.5 mM caffeine for 24 hours, the migration of C6 glioma cell was reduced. The expressions of phosphorylated focal adhesion kinase (FAK) and paxillin were decreased, while total proteins of FAK and paxillin were unaffected after 24 hours treatment of caffeine. By immunocytochemistry, p-FAK staining was decreased at the edge of the cell and actin stress fibers were disassembly after caffeine treatment. Moreover, a Rho-associated protein kinase (ROCK) inhibitor, Y27632, blocked caffeine-reduced the expressions of p-FAK and p-paxillin and migration. By siRNA knockdown of ROCK protein expression, cells transfected with ROCK siRNA decreased both total and phosphorylated proteins of FAK and paxillin, and cell migration in C6 glioma cells. Besides, the decreased migration induced by caffeine was abrogated after ROCK knock down. These results showed that caffeine declined the migration of C6 glioma cell by ROCK-focal adhesion proteins cascades. On the other hand, caffeine decreased the expression of phosphorylated Akt after 24 hours treatment. Both protein phosphatase 2A inhibitors, calyculin A and okadaic acid, prevented caffeine-reduced Akt phosphorylation, but not the migration. These results showed that Akt was not related to caffeine-reduced migration in C6 glioma cells. In summary, caffeine inhibited focal adhesion proteins by ROCK activation, resulting in the reduction of migration which was Akt independent in C6 glioma cells.
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