Differentiation of HL-60 cells towards macrophage-like cells by PMA. HL-60 cells were treated with 10⁻⁸ mol/L PMA for 6 days and SERCA expression was determined. (A) Immunoblot staining for SERCA 2b and SERCA_PLIM using the IID8 and the PLIM430 antibodies, respectively. (B) Densitometric analysis of SERCA expression in PMA-treated cells. (□) SERCA 2b; (•) SERCA_PLIM. (C) Induction of CD11c expression by PMA-treated HL-60 cells. (D and E) Selective inhibition of the PMA-induced overexpression of SERCA_PLIM by dexamethasone. HL-60 cells were treated for 5 days with 10⁻⁸ mol/L PMA in the presence of various concentrations of the glucocorticoid dexamethasone. (D) Immunostaining for SERCA 2b and SERCA_PLIM using the IID8 and PLIM430 monoclonal antibodies, respectively. (E) Densitometric analysis of the expression levels of (□) SERCA 2b and (▪) SERCA_PLIM in cells treated with PMA and dexamethasone (100% refers to SERCA expression of cells treated with PMA only). Data represent the mean ± SEM of 6 experiments.