Kinome-wide siRNA lethality screening in myeloma cells. Prevalidated siRNA directed against 639 human kinases and associated subunits were transfected into (A) KMS11 and (B) IL6-dependent INA6 human multiple myeloma cells in high-throughput screening experiments using 2 siRNAs per target tested in a single-siRNA-per-well format. Cell viability was determined at 96 hours by adenosine triphosphate concentration. siRNA-induced changes in viability are shown, measured in units of standard deviation (B-score) from the median of noninhibitory siRNA, plotted in the order in which siRNAs were screened. Cells treated with transfection reagent alone, GFP siRNA, or 1 of 2 unique nonsilencing (NS) scrambled siRNAs represent negative controls. Positive controls for transfection efficiency were included at regular intervals throughout the screen and are cells treated with an siRNA targeting ubiquitin B. (C-D) Results of kinome siRNA studies in myeloma cells were highly reproducible, with significant correlation between duplicate studies performed at separate times on KMS11 and on INA6, respectively. (E-F) Operative transfection efficiency during primary kinome screening studies in (E) KMS11 and (F) INA6, measured by modulation of viability by control siRNA. The median result for each condition is shown. (G) Kinases in KMS11 and INA6 myeloma cells associated with at least 1 lethal siRNA (with B-score < −3) during kinome-scale screening; top-ranked kinases were forwarded to validation studies.