[Study on apoptosis of leukemic lymphocytes mediated by purinergic P2z receptors].
OBJECTIVE
To investigate the role of purinergic P2z receptors in human leukemic lymphocyte apoptosis induced by extracellular adenosine triphosphate (ATP).


METHODS
Eleven B-CLL patients were studied. Leukemic lymphocytes with (n = 8) or without (n = 3) P2z receptors were exposed in vitro to ATP, benzoyl-benzoic-ATP (BzATP), 2-methylthio-ATP(2MeSATP), adenosine-5'-[gamma-thio] triphosphate (ATP-gamma S), and other nucleosides for 8 h. Apoptosis was detected by electron microscopy (EM), agarose gel electrophoresis, and quantitative TdT assay.


RESULTS
Apoptosis was detected only in leukemic lymphocytes with P2z receptors. By using the quantitative assay, ATP-inducing DNA strand breaks were found to occur specifically for BzATP, ATP and 2MeSATP, but not for ATP-gamma S and other nucleosides. Meanwhile, ATP-inducing DNA fragmentation was fully blocked by pretreatment with oxidized ATP (OxATP), a compound recently shown to block P2z receptors. Ca2+/Calmodulin complex played a role in the regulation of the CLL cell apoptosis induced by ATP, because an antagonist of this complex, 1-[N,O-bis (5-isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4-phenylpiperazine (KN-62), was found to inhibit the ATP-inducing apoptosis.


CONCLUSIONS
P2z receptors on lymphocytes play an important role in the apoptosis induced by ATP in vitro.
Peng
L
L
Department of Laboratory Medicine, First Affiliated Hospital, West China University of Medical Sciences, Chengdu 610041.
Bradley
C J
CJ
Wiley
J S
JS
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D017209:Apoptosis; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000473:pathology*; D018048:Receptors, Purinergic P2 / Q000378:metabolism*; D058486:Receptors, Purinergic P2X7; D014407:Tumor Cells, Cultured
C546468:P2RX7 protein, human; D018048:Receptors, Purinergic P2; D058486:Receptors, Purinergic P2X7; C017199:2',3'-dialdehyde ATP; D000255:Adenosine Triphosphate