DNA repair after irradiation in glioma cells and normal human astrocytes.

We examined DNA damage responses and repair in four human glioma cell lines (A7, U87, T98G, and U373) and normal human astrocytes (NHAs) after clinically relevant radiation doses to establish whether we could identify differences among them that might suggest new approaches to selective radiosensitization. We used phosphorylation of histone H2AX visualized by immunocytochemistry to assess DNA double-strand break (DSB) formation and resolution. Fluorescence immunocytochemistry was used to visualize and quantify repair foci.