Proteasome inhibitors can be used as potential therapeutic strategy against EBV associated B-cell lymphomas.

(A-C) 1 × 10⁵ LCLs (LCL#1 and LCL#89) were either left untreated (DMSO control) or treated with increasing concentrations of MG132 (1–5 μM) or bortezomib (0.5–1 μM) for 24 h and subjected for soft agar colony formation assay as described in the “Materials and Methods” section. After 14 days colonies were stained with 0.1% crystal violet and scanned using Odyssey CLx Imaging System and the number of colonies were measured by Image J software and plotted as bar diagrams in (C). Prior to staining, each well was also photographed (bright-field) using a Fluorescent Cell Imager as shown in (B). (D) ~0.5 × 10⁵ LCLs (LCL#1 and LCL#89) plated into each well of six-well plates were either left untreated (DMSO control) or treated with increasing concentrations (0–10 μM) of MG132 or bortezomib for the indicated time points at 37°C in a humidified CO₂ chamber. Viable cells from each well were measured by Trypan blue exclusion method using an automated cell counter. (E) ~0.5 × 10⁵ LCLs (LCL#1 and LCL#89) plated into each well of six-well plates were either left untreated (DMSO control) or treated with 5 μM MG132 or 0.5 μM bortezomib for 24 h were subjected to apoptosis assay using annexin V/propidium iodide (PI) staining. FITC labeled annexin V binding (Ex = 488 nm; Em = 350 nm) and PI staining were detected using BD FACSAria III. Error bars represent standard deviations of duplicate assays of two independent experiments. *, **, *** = p-value < 0.01, 0.005 and 0.001 respectively.