Correlation between Dex-resistance, constitutive NF-κB DNA binding, and endogenous bcl-2 protein levels. RPMI8226, ARH77, parental, and bcl-2 ARP-1 transfectants were cultured with or without the indicated concentration of Dex for 20 hours (A) WCEs were prepared and analyzed for NF-κB DNA binding by EMSA with a radiolabeled κB probe (B) and (C) WCEs were blotted with antibody specific for (B) bcl-2 and (C) Iκ.