Expression of Hsp27 (WT) in Dex-sensitive MM.1S cells increases resistance to Dex. (A) Functional specificity of Hsp27 (WT) was determined by subjecting protein lysates from Hsp27 (WT)-transfected or control vector-transfected MM.1S cells to immunoblot analysis with anti-Hsp27 (upper panel) or anti-tubulin antibodies (lower panels). Blots are representative of 3 independent experiments with similar results. (B) MM.1S cells were transiently transfected with cDNA expression construct containing GFP-tagged Hsp27 (WT) (•) or with empty vector alone (▪). GFP⁺ cells were selected by flow cytometry, treated with Dex (5 μM) for 12, 24, 48, or 72 hours, and analyzed for cell viability by an MTT assay. Median viability was 30% (24 hours), 10% (48 hours), and 4% (72 hours) after Dex treatment of empty vector-transfected cells and 79% (24 hours), 63% (48 hours), and 54% (72 hours) after Dex treatment of Hsp27 (WT)-transfected MM.1S cells (P = .04, as determined by one-sided Wilcoxon rank sum test). Error bars represent standard deviation.