Cytotoxicity assay
In a 96 well plate, 5,000 U2OS WT cells were seeded and cultured for 24
hours under standard culture conditions. Treated cells with various
concentrations of doxorubicin hydrochloride for 24 and 48 hours. After
24 and 48 h, LDH activity was measured using reagents from CyQUANT LDH
Cytotoxicity Assay Kit (C20300, invitrogen). Absorbance was read at 490
nm and 680 nm to determine LDH activity. Percent cytotoxicity was
calculated using the following: [(Compound-treated LDH
activity-Spontaneous LDH activity)/(Maximum LDH activity-Spontaneous LDH
activity)] *100.