E2F4 and ovarian carcinoma: To determine whether mTOR inhibition had a similar effect in ovarian cancer, we treated A2780 and SKOv3 cells with 50 nM rapamycin (as optimized for inhibition of mTOR without significant cell toxicity) for 4–8 h, and observed the effects on E2F1 and E2F4 protein expression and the corresponding DIRAS3 mRNA expression.