Merbarone

Merbarone (NSC 336628) is an orally active inhibitor of topoisomerase II. Merbarone acts primarily by blocking topoisomerase II-mediated DNA cleavage without stabilizing topo II-DNA covalent complexes. Merbarone is an anticancer agent^[1][2][4]. IC50 & Target: topoisomerase II^[1] In Vitro: Merbarone (1-100 μM) inhibits L1210 cells proliferation in a concentration-dependent manner, with an IC₅₀ of 10 μM^[3].
Merbarone (10-200 μM; 10 min) inhibits DNA relaxation catalyzed by human topoisomerase IIα, with an IC₅₀ of ～40 μM^[1].
Merbarone (25-200 μM; 6 min) blocks tyopoisomerase II-mediated DNA cleavage, with an IC₅₀ of ～50 μM^[1].
Merbarone (100 μM; 6 min) inhibits topoisomerase II-mediated DNA cleavage in a global manner^[1].
Merbarone (100 μM; 6 min) does not impair topoisomerase II?DNA binding^[1].
Merbarone (200 μM; 4-16 min) does not inhibit topoisomerase II-catalyzed ATP hydrolysis^[1]. In Vivo: Merbarone (50 mg/kg; daily i.p. for 5 d) achieves a maximum increased life span (ILS) of 101% in P388 murine leukemia^[2].
Merbarone (124 mg/kg; daily p.o. for 9 d) has anti-tumor activity in mice^[2].