A cyclic AMP binding protein pattern useful as a biochemical differentiation marker of erythroleukemic cell lines and normal cloned erythroblasts

Abstract

Previous study of a variety of a human hemopoietic cell lines and normal samples with 8-N 3- 32p-cAMP photoaffinity labelling, SDS-polyacrylamide gel electrophoresis and autoradiography revealed five distinct cAMP binding protein patterns, each of which were restricted to cells of particular lineages. One pattern unique to K562 cells was characterized by the presence of three bands designated a, b and d. In order to ascertain the significance of this finding, we studied by the same methods normal human erythroblasts harvested from methylcellulose cultures of fetal liver and adult blood, and murine and human erythroleukemic cells (MEL and HEL) as well as K562, cultured with and without chemical inducers of erythrodifferentiation. Three band patterns recognizable as similar to that of K562, but distinctive from those of myeloid and lymphoid cells, were noted of cells of erythroblastic origin. Both HEL and MEL, as well as the normal erythroblasts, exhibited heaviest labelling of band a in contrast to K562, which exhibited heaviest labelling of band d. Relative labelling of band b and d of HEL and MEL increased following treatment with 50 μ hemin or 4 mM hexamethylenebisacetamide (HMBA), respectively. Treatment of K562 with hemin, however, resulted in increased band a. Thus, among hemopoietic cells, an isozymic cAMP binding protein pattern has been identified which is characteristic of the erythroid lineage. The relative abundances of the three components ( a, b and d) have been furthermore noted to undergo a series of shifts during induced differentiation. Cyclic AMP binding proteins may thus prove useful as a biochemical marker system in the recognition and analysis of erythroid differentiation.