Figure 1.

Synergism between F-ara-A and CDDP in CLL is independent of p53-functional status. (a) CLL cells of eight patients (patient nos. 2, 3, 5, 8, 11, 15, 18 and 22) were incubated for 48 h with CDDP at increasing doses (1–100 μm). Cell death was assessed by annexin-V/PI staining (as described in the Materials and methods section). The shaded area presents the concentration range attained on CDDP treatment in vivo (Monjanel-Mouterde et al., 2003). (b) CLL cells with functional p53 (n = 5; patient nos. 11, 12, 18, 21 and 22) were treated with increasing doses of F-ara-A (5–50 μm), with or without 10 μm CDDP, for 48 h. Cell death was assessed by annexin-V/PI staining. To correct for variation in base-line apoptosis levels (see a), specific apoptosis is depicted (as described in the Materials and methods section). Presented is mean + s.e.m. (*P<0.05; Mann–Whitney U-test). (c) CLL cells with dysfunctional p53 were treated with increasing doses of F-ara-A (5–50 μm), with or without 10 μm CDDP (n = 6; patients 1–6) or 10 μm oxaliplatin (n = 4; patient nos. 2, 3, 5 and 6) for 48 h. Cell death was assessed by annexin-V/PI staining. Presented is mean +s.e.m. (*P<0.05, **P<0.01; Mann–Whitney U-test). (d) Left panels: Cells of patient number 5 were treated with 10 μm CDDP and 10 μm F-ara-A (C+F) with or without preincubation with 20 μm Q-VD-OPh. Apoptosis was assessed after 48 h using annexin-V/PI-staining. Right graph: summarized data of 5 p53-dysfunctional CLL patients (patient nos. 1–3, 5 and 6). Bars represent mean+s.e.m. (**P<0.01; Mann–Whitney U-test).