Transcriptional regulation of the transferrin receptor in differentiating HL-60 leukemic cells.

HL-60 promyelocytic leukemia cells were induced to differentiate along the granulocytic pathway by treatment with dimethylsulfoxide. A significant decrease in transferrin receptor specific mRNA was seen as early as 4 hr after exposure to inducer. Relative to untreated controls, transcript levels decreased 5-fold within 24 hr of exposure to dimethylsulfoxide and remained depressed throughout a 6-day treatment period. Reductions in receptor transcripts preceded the loss of surface receptor which in turn preceded the expression of the differentiated phenotype. The findings demonstrate that differentiation-associated regulation of the transferrin receptor can occur at the transcriptional level.