Topoisomerase II alpha gene expression in childhood acute lymphoblastic leukemia.

摘要: Abstract Previously, we showed that in vitro resistance to daunorubicin (DNR) at initial diagnosis was related a poor long-term clinical outcome childhood acute lymphoblastic leukemia (ALL), and cells of relapsed ALL were more resistant DNR than untreated ALL. Topoisomerase II (Topo II) is an intracellular target for anthracyclines epipodophyllotoxins. Decreased levels and/or activity Topo have been associated with multidrug cell lines. We investigated alpha gene expression fresh leukemic samples from 19 children 14 using sensitive RNase protection assay. The cytotoxicity the inhibitors DNA teniposide (VM26) measured MTT assay, cycle distribution analyzed by flow cytometry. Results (1) DNR, but not VM26 compared samples; (2) large interpatient variations existed both results; (3) detectable 29/33 median 5% level relatively chemosensitive human small lung cancer line; (4) did differ between ALL; (5) positively correlated percentage S- G2M-phase, drugs tested. In conclusion, can be explained decreased expression, additional studies may need further exploration.