Effect of alantolactone on proliferation and growth of cisplatin sensitive (A2780) and cisplatin resistant (A2780/CR) ovarian cancer cells. (A) Chemical structure of alantolactone. (B) A2780 and A2780/CR cells were cultured and treated in 96 well plates in triplicates for 72 h. The cell proliferation was measured using CCK-8 assay kit. (C) A2780 and A2780/CR cells were plated in 6 well cell culture plates for 12 h. After treating the cells with indicated dose of ALT for 24 h, medium containing drug was removed and cells were washed. Drug-free medium was added and cells were cultured for 12 days. At the end, colonies were stained and quantified.