In vitro activity: BMH-21 causes proteasome-dependent destruction of RPA194, the large catalytic subunit protein of Pol I holocomplex. In U2OS cancer cell line, BMH-21 results in degradation of RPA194 and translocation of NCL with IC50 of 0.05 μM and 0.07 μM, respectively. By causing nucleolar stress, BMH-21 also shows potent inhibition on cell viability.

Cell Assay: The cells (U2OS osteosarcoma cells) are maintained at 37 °C in a humidified atmosphere containing 5% CO2. U2OS osteosarcoma cells are cultured in DMEM supplemented with 15% fetal bovine serum. Cells are plated in 96-well plates at a density of 10000 cells/well in triplicate and incubated for 48 h with the compounds. Viability is determined using WST-1 cell proliferation reagent.