Expression of Transcription Factors During Sodium Phenylacetate Induced Erythroid Differentiation in K562 Cells

ABSTRACT: During 15 days of treatment of K562 cells with sodium phenylacetate, we observed an increase in the cellular hemoglobin concentration with a similar increase in the expression of γ-globin mRNA. Morphological studies demonstrated characteristic features of erythroid differentiation and maturation. At the same time there was no change in the level of expression of the cell surface antigenes CD33, CD34, CD45, CD71 and glycophorin A. Likewise, the level of expression of the erythroid transcription factors GATA-1, GATA-2, NF-E2, SCL and RBTN2, all expressed in untreated K562 cells, did not increase during sodium phenylacetate induced erythroid differentiation. The expression of the nuclear factors Evi-1 and c-myb, known to inhibit erythroid differentiation, did not decrease. We conclude that sodium phenylacetate treatment of K562 cells increases γ-globin mRNA and induces cell maturation as judged by morphology without affecting the expression of the erythroid transcription factors, some of which are known to be involved in the regulation of β-like globin genes.