Role of LR1 in EGCG-induced myeloma cell death. (A) Elevated levels of LR1 (67 kDa) protein in myeloma cells. (Ai) Protein levels of LR1 were evaluated in 2 samples of normal PBMCs, 9 myeloma cell lines, and 5 myeloma patient samples, using a monoclonal antibody specific for LR; (ii) bar graph shows expression of LR1 protein, normalized to GAPDH levels, in normal and myeloma cells. (B-C) INA6 myeloma cells were cotransfected with Cy3-labeled nontargeting control (cont) and laminin receptor 1 (LR1) siRNAs. (B) Transfected cells were incubated for 72 hours and uptake of siRNA was monitored by a fluorescence microscope equipped with a Cy3 filter. (C) INA6 cells were transfected as described for panel B and LR1 protein level was determined by Western blot analysis. (D) EGCG induced myeloma cell death. INA6 myeloma cells were transfected with control siRNAs or siRNAs directed against LR1, and 24 hours later treated with 10 μM EGCG. Cell viability was determined on alternate days. Error bars indicate SEM of 3 independent experiments.