LACK OF CORRELATION BETWEEN DNA-DEPENDENT PROTEIN-KINASE ACTIVITY ANDTUMOR-CELL RADIOSENSITIVITY

Lack of DNA-dependent protein kinase (DNA-PK) activity confers radiose nsitivity and defective DNA double-strand break repair. Nine human mal ignant glioma cell lines were studied to determine whether differences in DNA-PK activity reflect differences in inherent radiosensitivity o r are predictive of tumor treatment response, DNA-PK activity was pres ent in all cell extracts, as were the DNA-PK proteins, DNA-PK catalyti c subunit, Ku p70, and Ku p80. No correlation was found between the le vels of DNA-PK activity and inherent radiosensitivity or in the tumor treatment response. These preliminary results suggest that variation i n DNA-PK activity may not be a determinant of clinical response in mal ignant glioma.