Evidence of the role of protein kinase C during aclacinomycin induction oferythroid differentiation in K562 cells

At subtoxic concentrations, aclacinomycin is effective in controlling eryth roid differentiation of K562, a human erythroleukemic cell line. To better understand early events implicated in this process, we have used bisindolyl maleimide (GF109203X), an inhibitor with a high selectivity for protein kin ase C (PKC), Our data show that GF109203X inhibits aclacinomycin effects on K562, evidenced by a strong reduction of hemoglobinized cells and a marked decrease of mRNA rates of erythroid genes. To establish firmly PKC involve ment, we also verified that aclacinomycin stimulates its rapid translocatio n, from the cytosolic to the membrane compartment. By Western blot analysis , we also show that after short induction times, PKC alpha was the most imp licated. (C) 1999 Federation of European Biochemical Societies.