Time-dependent effects of Dex and/or IL-6 on expression of p21 protein in OCI-My5 MM cells. Total lysates from OCI-My5 MM cells were prepared before (time 0) and after 2, 4, 8, 16, 24, 36, and 48 hours of culture with 10% FBS-Iscove's media alone, Dex (1 μmol/L), IL-6 (50 ng/mL), or Dex (1 μmol/L) + IL-6 (50 ng/mL). Cell lysates were immunoprecipitated with anti-p21 polyclonal Ab, followed by Western immunoblotting with anti-p21 MoAb.