Effects of Dex and/or IL-6 on expression of CDK2, CDK4, and CDK6; binding of p21 to CDK2, CDK4, and CDK6; expression of cyclin E and D2; and phosphorylation of RB in OCI-My5 MM cells. Total cells lysates were prepared from OCI-My5 MM cells cultured with media alone, IL-6 (50 ng/mL), Dex (1 μmol/L), or IL-6 (50 ng/mL) + Dex (1 μmol/L) for 16 hours. Lysates were immunoprecipitated with anti-CDK2, anti-CDK4, or anti-CDK6 polyclonal antibodies followed by Western immunoblotting with either the same antibodies or anti-p21 MoAb. Expression of cyclin E, cyclin D2, and pRB were analyzed by immunoprecipitation and Western immunoblotting using the same cell lysates.