Extracellular ATP couples to cAMP generation and granulocytic differentiation in human NB4 promyelocytic leukaemia cells

Priming of NB4 promyelocytic cells with all-trans retinoic acid, followed b y extracellular ATP in the presence of a phosphodiesterase inhibitor, eleva ted cAMP and activated protein kinase A. The order of potency for cAMP prod uction was ATP (EC50 = 95 +/- 13 mu mol/L) > ADP > AMP = adenosine. The ord er of potency of ATP analogues was 2'- and 3'-O-(4-benzoylbenzoyl)-ATP (EC5 0 = 54 +/- 15 mu mol/L) = adenosine 5'-O-(3-thio) triphosphate (EC50 = 66 /- 4 mu mol/L) > ATP > beta,gamma-methylene ATP (EC50 = 200 +/- 55 mu mol/L ). Adenosine 5'-O-thiomonophosphate and adenosine 5'-O-(2-thio) diphosphate inhibited ATP-induced cAMP production. Differentiation also occurred as me asured by increased expression of CD11b and N-formyl peptide receptor and c hanges in cell morphology. UTP did not elevate cAMP or induce differentiati on, indicating that P2Y(2), P2Y(4), and P2Y(6) receptors were not involved. The P2Y(11) receptor, a cAMP-linked receptor on promyelocytic HL-60 cells, was detected in NB4 cells by reverse transcription-polymerase chain reacti on and northern blotting. This receptor has the same order of potency with respect to cAMP production as that observed in HL-60 cells.