Pyrazoloacridine (NSC 366140), an intercalating agent with anti-cancer activity, inhibits the activity of topoisomerases 1 and 2. Pyrazoloacridine (NSC 366140) exhibits an IC 50 of 1.25 μM in K562 myeloid leukemia cells for 24 h treatment. In Vitro Pyrazoloacridine (NSC 366140, PD 115934) exhibits IC 50 values of 10.7 μM and 4.5 μM for oxic and hypoxic HCT-8 cells. Pyrazoloacridine (NSC 366140, 2-4 μM) abolishes the catalytic activity of both topo I and topo II in vitro. Pyrazoloacridine (NSC 366140) displays activity against cisplatin- and paclitaxel-resistant ovarian cancer. Pyrazoloacridine (NSC 366140) has been shown to cause delayed DNA fragmentation in MCF-7 breast cancer cells. Pyrazoloacridine (NSC 366140) induces apoptosis in P53-deficient Hep 3B human hepatoma cells. MCE has not independently confirmed the accuracy of these methods. They are for reference only. Cell Cytotoxicity AssayCell Line: K562 Myeloid Leukemia Cells. Concentration: 0-500 μM. Incubation Time: 1 h or 24 h. Result: When K562 cells were incubated with PA for 1 h and then plated in soft agar, an IC 50 of -50 μM was observed. In contrast, when cells were incubated for 24 h with PA, the IC 50 was 1.25 μM. Form:Solid