Costunolide-induced apoptosis in human leukemia cells: involvement of c-jun N-terminal kinase activation.
The authors previously reported that costunolide, an active compound isolated from the stem bark of Magnolia sieboldii, induced apoptosis via reactive oxygen species (ROS) and Bcl-2-dependent mitochondrial permeability transition in human leukemia cells. In the present study, the authors investigated whether mitogen-activated protein kinases (MAPKs) are involved in the costunolide-induced apoptosis in human promonocytic leukemia U937 cells. Treatment with costunolide resulted in the significant activation of c-Jun N-terminal kinase (JNK), but not of extracellular-signal-related kinase (ERK1/2) or p38. In vitro kinase assays showed that JNK activity was low in untreated cells but increased dramatically after 30 min of costunolide treatment. U937 cells co-treated with costunolide and sorbitol, a JNK activator, exhibited higher levels of cell death. In addition, inhibition of the JNK pathway using a dominant-negative mutation of c-jun and JNK inhibitor SP600125, significantly prevented costunolide-induced apoptosis. Furthermore, pretreatment with the antioxidant NAC (N-acetyl-L-cysteine) blocked the costunolide-stimulated activation of JNK while the overexpression of Bcl-2 failed to reverse JNK activation. Pretreatment with SP600125 recovered the costunolide-suppressed Bcl-2 expression. These results indicate that costunolide-induced JNK activation acts downstream of ROS but upstream of Bcl-2, and suggest that ROS-mediated JNK activation plays a key role in costunolide-induced apoptosis. Moreover, the administration of costunolide (intraperitoneally once a day for 7 d) significantly suppressed tumor growth and increased survival in 3LL Lewis lung carcinoma-bearing model.
Department of Oriental Pharmaceutical Science, College of Pharmacy, Kyung Hee University, Hoegi-Dong, Seoul 130-701, Republic of Korea.
Jung-Hye
JH
Choi
Kyung-Tae
KT
Lee
D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects*; D018827:Carcinoma, Lewis Lung / Q000188:drug therapy; D004359:Drug Therapy, Combination; D016166:Free Radical Scavengers / Q000494:pharmacology; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D007938:Leukemia / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D031566:Magnolia / Q000737:chemistry*; D051379:Mice; D008517:Phytotherapy; D024301:Plant Bark; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D018547:Plant Stems; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D012717:Sesquiterpenes / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D015398:Signal Transduction / Q000187:drug effects; D013012:Sorbitol / Q000494:pharmacology / Q000627:therapeutic use; D020298:U937 Cells; D007783:Lactones
D000111:Acetylcysteine; D000972:Antineoplastic Agents, Phytogenic; D016166:Free Radical Scavengers; D048031:JNK Mitogen-Activated Protein Kinases; D010936:Plant Extracts; D047428:Protein Kinase Inhibitors; D011505:Protein-Tyrosine Kinases; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012717:Sesquiterpenes; D013012:Sorbitol; C002602:costunolide; D007783:Lactones; C062333:ROS1 protein, human