Extracellular ATP-Dependent suppression of proliferation and induction of differentiation of human HL-60 leukemia cells by distinct mechanisms

Extracellular ATP suppressed the growth of HL-60 leukemia cells and induced their differentiation as revealed by N-formyl-methionyl-leucyl-phenylalani ne-induced beta -glucuronidase release. ATP degraded to ADP, AMP, and adeno sine, and the effect of ATF on cell growth was mimicked by these metabolite s added to the cultures. The stable analog alpha,beta -methylene ATP, howev er, had only a weak inhibitory effect on cell growth. Adenine nucleotide-in duced growth suppression was reversed by uridine, suggesting the involvemen t of intracellular pyrimidine starvation secondary to adenosine accumulatio n. Consistent with this, ATP induced intracellular starvation of pyrimidine nucleotides, and this effect was also prevented by pretreatment of cells w ith uridine. The order of effectiveness of ATP-incluced differentiation of HL-60 cells, unlike that for growth suppression, was ATP > ADP > AMP, and a denosine had no effect. Furthermore, uridine had no effect and the stable a nalog, alpha,beta -methylene ATP also induced HL-60 cell differentiation, s uggesting that differentiation was due to ATP-per se. We tested the hypothe sis that ATP-induced differentiation arises from activation of adenylyl cyc lase by the novel P2Y(11) receptor using the cell-permeable inhibitor of pr otein kinase A, Rp-CPT-cAMPS (8-(4-chlorophenylthio)adenosine3',5'-cyclic m onophosphorothioate, Rp isomer). Rp-CPT-cAMPS (1-100 muM) prevented ATP-ind uced differentiation of HL-60 cells as assessed by fMlP-induced beta -glucu ronidase release. However, Rp-CPT-cAMPS did not prevent ATP-induced growth suppression. Taken together, the data indicate that extracellular ATP suppr esses HL-60 growth and induces their differentiation by distinct mechanisms . Growth suppression arises from adenosine generation and consequent pyrimi dine starvation. Differentiation arises, at least in part, from a distinct mechanism involving the activation of cell surface P2 receptors coupled to cAMP generation and activation of protein kinase A. (C) 2000 Elsevier Scien ce Inc.