Inhibition of human malignant glioma cell motility and invasion in vitro by hypericin, a potent protein kinase C inhibitor.

The effect of hypericin, an antiviral drug and a potent protein kinase C (PKC) inhibitor, on glioma cell invasion was investigated in vitro. Treatment of the established human glioblastoma cell line, T98G, with 1 microM hypericin for 24 h resulted in a significant inhibition of the cell invasion through an artificial basement membrane, but not cell attachment or proliferation. Furthermore, tamoxifen and staurosporine, both PKC inhibitors, also inhibited T98G cell invasion, suggesting that PKC may be the cellular target for hypericin-inhibited glioma cell migration. Similarly, hypericin decreased cell motility significantly in established lines, T98G and U87-MG, and also in a low-passage human malignant glioma cell line. Thus, hypericin may prove useful for studying mechanisms of glioma invasion, and may represent a new agent in malignant glioma therapy.