Diindolylmethane (DIM) is minimally toxic to normal ovarian surface epithelium cells. (A) Effect of varying concentrations of DIM in NOSE and TOV-21G cells was determined by sulforhodamine B cell survival assay. Values are means ± SD of two independent experiments with eight replicates. (B) In another experiment, NOSE cells were exposed to different concentrations of DIM for 24 h. Cells were lysed and western blotting was performed as outlined in Methods. Representative immunoblots show the effect of DIM on the expression of phosphorylated signal transducer and activator of transcription 3 (p-STAT3) (Tyr 705) and STAT3. Blots were stripped and probed with actin to ensure proper loading.