Prostaglandin A2 activates intrinsic apoptotic pathway by direct interaction with mitochondria in HL-60 cells.
HL-60 cells treated by prostaglandin (PG) A(2) showed characteristics of apoptosis such as accumulation of hypodiploid and annexin V positive cells, condensed and fragmented nuclei, cytochrome c (Cyt C) release from mitochondria and activation of caspase-1, -2, -3, -7 and -9. PGA(2)-induced cell death was rescued by inhibitors of caspase-9 and -3, but PGA(2)-induced Cyt C release was not prevented by caspase inhibitors. During Cyt C release by PGA(2), mitochondrial transmembrane potential was maintained and mitochondrial permeability transition pore was not formed. In addition, anti-apoptotic BCL-2 family proteins like BCL-2 and BCL-XL, and ROS scavengers including ascorbic acid and 2,2,6,6-tetramethyl-1-piperidinyloxy were not able to inhibit Cyt C release as well as apoptosis by PGA(2). Finally, it was shown that PGA(2)-induced Cyt C release in vitro from purified mitochondria in the absence of cytosolic components. Furthermore, thiol-containing compounds such as N-acetylcysteine, l-cysteine and monothioglycerol prevented Cyt C release, and hence induction of apoptosis. Taken together, these results suggest that PGA(2) activates intrinsic apoptotic pathway by directly stimulating mitochondrial outer membrane permeabilization to release Cyt C, in which thiol-reactivity of PGA(2) plays a pivotal role.
Lee
Sun-Young
SY
Department of Biochemistry, College of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea.
Ahn
Ji-Hyun
JH
Ko
Kyoung Won
KW
Kim
Jaetaek
J
Jeong
Seong Whan
SW
Kim
In-Kyung
IK
Kim
Jin
J
Kim
Ho-Shik
HS
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D002463:Cell Membrane Permeability / Q000187:drug effects; D045304:Cytochromes c / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D016166:Free Radical Scavengers / Q000378:metabolism; D018922:HL-60 Cells; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism*; D051336:Mitochondrial Membranes / Q000187:drug effects / Q000378:metabolism; D011454:Prostaglandins A / Q000378:metabolism* / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D013438:Sulfhydryl Compounds / Q000378:metabolism
D016166:Free Radical Scavengers; D011454:Prostaglandins A; D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species; D013438:Sulfhydryl Compounds; D045304:Cytochromes c; D053148:Caspase 3; C100008:prostaglandin A2