Activation of ion channels in tumor cells by leukoregulin, a cytostatic lymphokine.
We used the whole-cell patch-clamp recording technique to study the effects of leukoregulin (LR), a cytostatic lymphokine produced by activated human peripheral blood lymphocytes, on the electrical properties of K562 tumor cells. LR induced changes in the membrane excitability in 33 of 55 cells studied. A minute or more after application, LR elicited a complex and reversible electrical response. The response lasted for several more minutes in the continued presence of LR. It consisted of (a) moderate-conductance (50 pS), cation-selective, ion-channel activity, (b) a shift of the zero-current membrane potential close to 0 mV, and (c) a suppression of a depolarization-activated K+ conductance. All of these changes in tumor cell excitability act coordinately to depolarize the tumor cells and may be important in the cytostatic actions of LR.
Sheehy
P A
PA
Laboratory of Neurophysiology, National Institute of Neurological and Communicative Disorders and Stroke, Bethesda, MD 20892.
Barnett
S C
SC
Evans
C H
CH
Barker
J L
JL
D006801:Humans; D007473:Ion Channels / Q000187:drug effects*; D004915:Leukemia, Erythroblastic, Acute / Q000503:physiopathology; D008222:Lymphokines / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects; D011188:Potassium / Q000378:metabolism; D014407:Tumor Cells, Cultured / Q000187:drug effects
D007473:Ion Channels; D008222:Lymphokines; C044162:leukoregulin; D011188:Potassium