Effect of erythroid differentiation factor on erythroid differentiation and proliferation of K-562 cells.

The effects of erythroid differentiation factor (EDF) on the levels of zeta-globin and several proto-oncogene mRNAs and transferrin receptors (Tf-R) of K-562 cells were examined. EDF decreased Tf-R expression and increased the level of zeta-globin mRNA. The mRNA level of c-fos began to rise within 3 hours and continued to increase up to 72 hours, but the levels of c-myb and c-abl decreased to 23 and 19%, respectively, of their initial levels after 48 hours. In contrast, the mRNA levels of c-myc and c-fms decreased transiently, but recovered within 48 hours. The modulation of several proto-oncogene mRNA levels was observed much earlier than the differentiation induction and the growth inhibition of K-562 cells by EDF.