Survivin promotes drug resistance. (A) 15 unsorted primary pre–B-ALL (1-15) and 3 unsorted primary T-ALL cases (16-18) and LPS-stimulated proliferating and unstimulated CD19⁺ B cells as controls (n = 3, supplemental Figure 1) were studied for survivin mRNA levels by qRT-PCR (top panel) and survivin protein expression by Western analysis (bottom panel). Major karyotypes or the primary cases are indicated at the top of the figure and are listed in supplemental Table 1. Survivin is significantly more expressed in primary ALL cells (n = 18) compared with normal CD19⁺ B-cell controls (n = 3; 3.46 ± 2.38 vs 0.26 ± 0.06, respectively; Survivin /GAPDH-fold increase; P < .02). *P < .05; no symbol indicates P < .005. (B) A human survivin promoter–driven GFP lentiviral reporter (survivin reporter-GFP) was used in LAX7R cells. Unsorted bulk ALL or ALL cells FACS sorted for GFP^High and GFP^Low were analyzed for survivin expression by qRT-PCR. *P < .05. (C) Unsorted, LAX7R cells transduced with the survivin reporter GFP were treated with either media control or a combination of VDL (V, 1nM; D, 0.1nM; and L, 0.01 IU) for 48 hours and analyzed for apoptosis by flow cytometry after annexin V costaining. (D) Viable annexin V⁻/7-AAD⁻ LAX7R cells after VDL or control treatment were further analyzed by flow cytometry for survivin reporter-GFP expression. (E) A lentiviral survivin IRES GFP (survivin-GFP) was used to overexpress survivin in ALL. Survivin-GFP ALL cells and empty-GFP controls were treated in vitro with V alone (left panel) or with the VDL combined therapy, as in panel D (right). Viability was assessed by MTT assay. (F) Primary ALL cells (LAX7R) cells transduced with either nonsilencing or survivin shRNA were treated with V at the indicated doses and viability was assessed with an MTT assay. Asterisks (*) denote statistical significance between survivin shRNA knock-down and controls.