An immunosuppressive agent, FTY720, increases intracellular concentration of calcium ion and induces apoptosis in HL-60.
We previously reported that FTY720 is an efficient inducer of apoptosis in lymphocytes and cultured cell lines. In the present study, HL-60 human promyerocytoma cells also induced apoptosis through in vitro treatment with the drug, demonstrating extensive DNA fragmentation 6 hr after incubation. The major target of FTY720 was the common signalling pathway of apoptosis, since a rapid (< 1 min) increase in the intracellular Ca2+ concentration ([Ca2+]i) was found in the cells treated with the drug. Calcium chelation in the culture medium with EGTA did not affect the [Ca2+]i mobilization. A phospholipase C inhibitor, U73122, inhibited the increase in [Ca2+]i as well as the fragmentation of the nuclear DNA, whereas U73343, a non-effective analogue of U73122, had little effect. These results suggest that FTY720-induced apoptosis is mediated through an activation of phospholipase C and the subsequent release of Ca2+ from intracellular calcium pools. In addition, the treatment of HL-60 with pertussis toxin (PTX) did not inhibit Ca2+ mobilization or apoptosis, suggesting that the activation of phospholipase C is independent of PTX-sensitive G-proteins.
Shinomiya
T
T
Department of Experimental Surgery and Bioengineering, National Children's Medical Research Centre, Tokyo, Japan.
Li
X K
XK
Amemiya
H
H
Suzuki
S
S
D017209:Apoptosis / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism*; D053938:DNA Fragmentation / Q000187:drug effects; D004963:Estrenes / Q000494:pharmacology; D000068876:Fingolimod Hydrochloride; D018922:HL-60 Cells; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D008214:Lymphocytes / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D037342:Pertussis Toxin; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D011409:Propylene Glycols / Q000494:pharmacology*; D011760:Pyrrolidinones / Q000494:pharmacology; D013110:Sphingosine / Q000031:analogs & derivatives; D010738:Type C Phospholipases / Q000502:physiology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D004963:Estrenes; D007166:Immunosuppressive Agents; D010726:Phosphodiesterase Inhibitors; D011409:Propylene Glycols; D011760:Pyrrolidinones; D010566:Virulence Factors, Bordetella; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D037342:Pertussis Toxin; D010738:Type C Phospholipases; D000068876:Fingolimod Hydrochloride; D013110:Sphingosine; D002118:Calcium