Expression of Hsp27 correlates with Dex sensitivity and Dex resistance in MM cells. (A) Total cell lysates from MM.1S, MM.1R, RPMI-8226, and U266 MM cells were prepared. Lysates were separated by 10% SDS-PAGE and analyzed by immunoblotting (IB) with anti-Hsp27 or anti-tubulin antibodies. (B) Cells were treated with 5 μM Dex for 24 hours and analyzed for apoptosis by PARP cleavage. Lysates were subjected to immunoblot analysis with anti-PARP antibody. (C,E) Expression of Hsp27 in purified patient MM cells. Lysates from patient MM cells (Dex sensitive, patients no. 1 and 4) and (Dex resistant, patients no. 2 and 3) were subjected to immunoblot analysis with anti-Hsp27 and antitubulin antibodies. (D,F) Patient MM cells were treated with 5 μM Dex for 24 hours and analyzed for apoptosis by PARP cleavage. Lysates were subjected to immunoblot analysis with anti-PARP antibody. Blots are representative of 3 independent experiments with similar results. FL indicates full length; CF, cleaved fragment.