Induction of erythroid differentiadon in K562 cells by different butyrate regimens

OBJECTIVE: To investigate the hemoglobinization induced by butyrate and observe the effects of different butyrate regimens on erythroid differentiation of K562 cells. METHODS: K562 cells, used as an in vitro model system, were stained with benzidine to assess hemoglobin (Hb) production in response to different treatment regimens of butyrate at varied concentrations. Comparison of the percentage of benzidine-positive cells (BZ%)in untreated and butyrate-treated K562 cells was performed. Protein absorption at 414 nm using a spectrophotometer and cellulose acetate gel electrophoresis were employed to determine the changes of Hb production in K562 cells. RESULT: The BZ% increased by 4 to 6 fold and Hb production by 9 to 14 fold 3 d after the cells were incubated with butyrate which selectively promoted fetal hemoglobin(HbF) production in K562 cells. The BZ% increased gradually and reached the peak of l9% to 28% on day 3 or 4 in cells receiving pulse treatment with butyrate for only once, followed by a subsequent rapid fall and on day 7 to 9, it decreased to the level of untreated K562 cells. The length of time for incubation with butyrate was not related to in the increment or the maintenance of the increased level of BZ%. Continuous treatment with butyrate yielded a similar result to that of a single administration of pulse treatment. In contrast, in cells with intermittent pulse treatment the BZ% reached a peak after 72 h and was maintained between 20% and 30% till 3 cycles of treatment was completed. CONCLUSION: Butyrate can induce the expression of globin genes and augment Hb producfion especially that of HbF. A sustained erythroid differentiation of K562 cells can be achieved by intermittent pulse treatment with butyrate which can be an ideal regimen for children with beta globin diseases.