Document Detail

K562 leukemia cells express P2T (adenosine diphosphate) purinergic receptors.
MedLine Citation:
PMID:  1578375     Owner:  NLM     Status:  MEDLINE    
The P2T purinergic receptor for ADP has previously been found only in platelets. We investigated the effect of ADP on the concentration of intracellular free calcium ([Ca++]i) in fura-2-loaded K562 leukemia cells, a cell line with the potential for megakaryocytic differentiation. ADP causes a rapid and transient increase in [Ca++]i, which peaks within 5 to 10 sec. The EC50 for this response is 0.4 microM. A major portion of the increased calcium is due to mobilization of intracellular stores because the response to ADP is only partially reduced in the absence of extracellular calcium. Exposure to ADP desensitizes K562 cells to additional administrations of this nucleotide. Pretreatment of K562 cells with the protein kinase C activator phorbol 12-myristate 13-acetate completely blocks the response to ADP. This effect of phorbol 12-myristate 13-acetate is prevented by the protein kinase C inhibitor staurosporine, but staurosporine does not affect the progression of desensitization after repeated ADP exposures. ATP does not increase [Ca++]i in K562 cells, but antagonizes the response to ADP. We propose that the P2T receptor for ADP in K562 cells is an early marker for megakaryocytic differentiation. Furthermore, this immortalized nucleated cell line may be a useful model to decipher the signal transduction pathways involved in the ADP response.
A J Murgo; F D Sistare
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Journal of pharmacology and experimental therapeutics     Volume:  261     ISSN:  0022-3565     ISO Abbreviation:  J. Pharmacol. Exp. Ther.     Publication Date:  1992 May 
Date Detail:
Created Date:  1992-06-05     Completed Date:  1992-06-05     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0376362     Medline TA:  J Pharmacol Exp Ther     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  580-5     Citation Subset:  IM    
Division of Research and Testing, Food and Drug Administration, Washington, DC.
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MeSH Terms
Adenosine Diphosphate / pharmacology*
Adenosine Triphosphate / antagonists & inhibitors
Alkaloids / pharmacology*
Calcium / metabolism*
Fura-2 / pharmacology
Leukemia / metabolism*
Protein Kinase C / antagonists & inhibitors
Receptors, Purinergic / drug effects*
Tetradecanoylphorbol Acetate / pharmacology
Tumor Cells, Cultured
Reg. No./Substance:
0/Alkaloids; 0/Receptors, Purinergic; 16561-29-8/Tetradecanoylphorbol Acetate; 56-65-5/Adenosine Triphosphate; 58-64-0/Adenosine Diphosphate; 62996-74-1/Staurosporine; 7440-70-2/Calcium; 96314-98-6/Fura-2; EC Kinase C

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