Enhancement of radiosensitivity in human malignant glioma cells by hypericin in vitro

Clin Cancer Res. 1996 May;2(5):843-6.

Abstract

Hypericin, an antidepressant and antiviral agent being evaluated in phase I and II trials for patients with HIV infection, is known to be a potent protein kinase C inhibitor. We have investigated its effects on cellular response to radiation via a tetrazolium-formazan cell growth rate assay using 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide and clonogenic assay in three human glioblastoma cell lines, U87-MG, A-172, and T98G, and a low-passage malignant glioma culture, 93-492. At a concentration of 5 microM, hypericin inhibited these cells slightly but caused significant radiosensitization (e.g., the cell survival rate after the radiation treatment was 50.2 and 26.0% in cells treated with 6 Gy and 6 Gy plus 5 microM hypericin in U87-MG cells, respectively; P = 0.0285). Hypericin also enhanced the radiosensitivity significantly in the low-passage glioma 93-492 cells. These findings suggest that hypericin represents a potential new agent in combination with radiation therapy of malignant gliomas.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Anthracenes
  • Glioma / radiotherapy*
  • Humans
  • Perylene / analogs & derivatives*
  • Perylene / pharmacology
  • Protein Kinase C / antagonists & inhibitors
  • Radiation-Sensitizing Agents / pharmacology*
  • Tumor Cells, Cultured

Substances

  • Anthracenes
  • Radiation-Sensitizing Agents
  • Perylene
  • hypericin
  • Protein Kinase C