Endonuclease activity and hydrogen peroxide-induced cytotoxicity in human glioblastoma and glioma cell lines.

ABSTRACT

Hydrogen peroxide (H2O2) induced internucleosomal DNA cleavage in human myelogenous leukemic cell lines (HL-60, ML-1, THP-1, U-937), but not in human glioblastoma (T98G, U87MG) and glioma (KG1C) cell lines. However, H2O2 produced apoptotic cells, characterized by cell shrinkage, nuclear fragmentation and chromatin condensation in glioblastoma and glioma cell lines. Autodigestion experiments revealed that the major endonucleases, present in all leukemic, glioblastoma and glioma cell lines, were divalent cation-independent endonuclease(s). The endonudease(s) present in the lysates of all these cells were activated at acidic, but not at neutral pH. The results suggest that the endonuclease activity might be differently regulated between leukemic and glioma cell lines.