Effect of MβCD and nystatin on MDA-MB-231 and ZR 751 cells. (A) and (B). Cholesterol depletion/chelation by MβCD and nystatin. MDA-MB-231 and ZR 751 cells were treated with different concentrations of MβCD and nystatin for 1 hr, and cholesterol levels were measured at 1 and 24 hrs in (A) MDA-MB-231 and (B) ZR 751 cells. The percentage reduction in cholesterol upon drug treatment was calculated with respect to total cholesterol in the untreated cells, which is taken as 100%. Each reaction was performed in duplicate and each point represents the mean ± S.D. of three independent experiments. (C) MDAMB 231 and ZR 751 cells were incubated with different concentrations of MβCD for 1 h, 4 h, 24 h and 48 h. Supernatants were collected and assessed for cellular toxicity by using a lactate dehydrogenase assay kit. The data is represented as percentage cytoxicity with reference to untreated cells.