Altered expression of cell cycle regulatory proteins in A2780 and A2780/CP cells following β-elemene treatment. A2780 and A2780/CP cells were treated with β-elemene at the indicated concentrations for 48 h, and cell proteins were extracted. Extracted proteins (60 μg) from drug-treated and untreated cells were separated by SDS-PAGE and immunoblotted with antibodies against cyclin A, cyclin B1, cyclin-dependent kinase 1 (CDK1), also known as cell division control protein 2 homolog (CDC2), phospho-CDC2 (Tyr15), phospho-CDC2 (Thr161), p53, p21WAF1/CIP1, and CDC25C, respectively. β-Actin was used as a loading control. Western blot data are representative of those obtained from three separate experiments.