Ar. Cattan et al., METHOD FOR QUANTIFYING EXPRESSION OF FUNCTIONALLY ACTIVE TOPOISOMERASE-II IN PATIENTS WITH LEUKEMIA, Journal of Clinical Pathology, 49(10), 1996, pp. 848-852
Aims-To produce a method to measure and quantify enzymatically active
topoisomerase II in normal and neoplastic human cells. Methods-A crude
cell lysate from density separated mononuclear cells from either peri
pherial blood or bone marrow was prepared as a source of topoisomerase
s. Using the lysate, minicircles from the Crithedia kinetoplast DNA co
mplex were decatenated before being separated by agarose gel electroph
oresis and visualised using ethidium bromide/ultraviolet fluorescence.
Results-Cell number, sample volume and drug inhibition concentration
required to produce reliable and reproducible assay conditions were es
tablished. Intra- and interassay standards were included which permitt
ed the quantification of active topoisomerase II in matched peripheral
blood, bone marrow, presentation, and relapse samples from patients w
ith acute lymphoblastic leukaemia. Active topoisomerase II has been co
nverted to a unit scale which has been used to compare topoisomerase I
I activities in cells from patients with normal blood and bone marrow
samples. Conclusions-There was no change in topoisomerase II activitie
s between samples taken at presentation and those taken during a recur
rence. However, topoisomerase II activity in leukaemic blast populatio
ns was increased compared with topoisomerase II active in normal cells
.