Aza/pano pretreatment modulates CD19 surface expression through CD81 modulation and disrupts BTK-mediated prosurvival signaling. (A) Flow cytometry plot overlays showing the surface expression of CD19 in aza/pano-treated Nalm6 cells compared with untreated. Isotype control antibody plots are included for reference. Representative plots of 3 independent trials are shown. (B-C) Western blot analysis of phosphorylated BTK, p53, Bax, caspase-3 and PARP in WT, WT pretreated with aza/pano for 48 hours and/or treated with Ara-C for 16 hours in coculture with Saos2. Nalm6 cells collected from coculture were confirmed to be a pure leukemic cell population (>99%) and all viabilities following treatment were >70%. The numbers below the blots indicate average fold change of protein normalized to GAPDH (loading control) with respect to control (assigned value = 1.00) from 3 independent experiments.