D609 inhibits the proliferation of neural progenitor cells

We examined the effect of tricyclodecan-9-yl-xanthogenate (D609), a phosphatidylcholine-specific phospholipase C inhibitor, on the proliferation of adult neural progenitor cells in vitro. D609 (100 microM) decreased the proliferation of neural progenitor cells as measured by the proliferation assay, bromodeoxyuridine incorporation, and cell counting without causing cell death. Immunoblot analysis showed a decrease in the expression of cyclin D1 and phosphorylation of retinoblastoma after the incubation of cells with D609. These results suggest that D609 inhibits the proliferation of neural progenitor cells by reducing the cyclin D1 content resulting in decreased phosphorylation of retinoblastoma and subsequent inhibition of cell division.