[Proliferation inhibition of glioma cells by vitamin K2]

The antitumor effects of vitamin K2 were studied using three glioma cell lines: C6 (rat glioma cell), RBR17T and T98G (human glioma cell). The antitumor effects were estimated by count assay. The results was that vitamin K2 induced growth inhibition in a dose-dependent manner. The RBR 17T cells exposed to vitamin K2 for 72 hours resulted in oligonucleosomal DNA fragmentation and formed a ladder on agarose gel electrophoresis. Furthermore, the RBR17T cells exposed to vitamin K2 for 24 hours were significantly accumulated in the G0G1 phase of the cell cycle. Those results suggested that vitamin K2 can inhibit the proliferation of cells through the induction of cell cycle arrest and apoptosis for tumor cells. The combined treatment of vitamin K2 with ACNU or 5-FU or INF-beta or 1,25-dihydroxyvitamin D3 enhanced growth inhibition significantly. In conclusion, vitamin K2 can be a useful drug for the treatment of glioma.