Fig. 4.

Additive effect of and 15d-PGJ₂ and PI3-K inhibitor on the anti-tumor activity of topoisomerase inhibitors in Caki-2 cells. (A) Caki-2 cells were assayed for nuclear chromatin condensation following treatment for 20 h (open columns) or 24 h (filled columns) with 20 μM 15d-PGJ₂ in the absence or presence of 70 μM VP-16. Data are expressed as means±SE. (n=12). Since chromatin-condensed nucleus were not detected in the control culture at 20 h, significant difference compared with the control culture could not be tested. ^*P<0.05, compared with control (24 h). (B) Caki-2 cells were treated with LY294002 at the indicated concentrations in the absence (circles) or presence of 1 μM camptothecin (triangles) or 30 μM VP-16 (squares) for 24 h. Cell viabilities were determined by MTT reducing activity. Data are expressed as means±SE. (n=6). ^**P<0.01, compared with control. ##P<0.01, compared with camptothecin or VP-16 alone.