Abstract
The influence of the protein kinase A (A kinase) system in differentiation of HL-60-Eo cells to eosinophils induced by histamine was studied. Although 8-Cl-cAMP caused inhibitions of proliferation and [3H]thymidine uptake of HL-60-Eo cells similarly to histamine, no significant eosinophilic differentiation was observed. Histamine as well as 8-Cl-cAMP caused elevation of A kinase activity. However, KT-5720, an inhibitor of A kinase, had no effect on histamine-induced eosinophil differentiation. RIα antisense oligodeoxynucleotide caused significant inhibition of HL-60-Eo cell growth, but RIIβ antisense oligodeoxynucleotide had no effect. On the other hand, neither of the antisense oligodeoxynucleotides showed potentiating effects on growth inhibition induced by histamine. In addition, RIα and RIIβ antisense oligodeoxynucleotides caused neither differentiation to eosinophils itself nor potentiation of histamine-induced differentiation. From these findings, it was concluded that A kinase is not correlated directly with differentiation of HL-60-Eo cells to eosinophils.
