Zerumbone, a bioactive sesquiterpene, induces G2/M cell cycle arrest and apoptosis in leukemia cells via a Fas- and mitochondria-mediated pathway.
We demonstrated here for the first time that zerumbone (ZER), a natural cyclic sesquiterpene, significantly suppressed the proliferation of promyelocytic leukemia NB4 cells among several leukemia cell lines, but not human umbilical vein endothelial cells (HUVECs), by inducing G2/M cell cycle arrest followed by apoptosis with 10 microM of IC50. Treatment of NB4 cells with growth-suppressive concentrations of ZER resulted in G2/M cell cycle arrest that was associated with a decline of Cyclin B1 protein, but with the phosphorylation of ATM/ Chk1/Chk2. In addition, ZER induced the phosphorylation of Cdc25C at the Thr48 residue and Cdc2 at the Thr14/Tyr15 residues. Furthermore, ZER-induced apoptosis in NB4 cells was initiated by the expression of Fas (CD95)/Fas Ligand (CD95L), concomitant with the activation of caspase-8. ZER was also found to induce the cleavage of Bid, a mediator that is known to connect the Fas/CD95 cell death receptor to the mitochondrial apoptosis pathway. ZER also induced the cleavage of Bax and Mcl-1 proteins, but not Bcl-2 or Bcl-XL. ZER-induced apoptosis took place in association with a loss of the mitochondrial transmembrane potential as well as the activation of caspase-3 and -9, resulting in the degradation of the proteolytic poly (ADP-ribose) polymerase (PARP). ZER also triggered a release of cytochrome c into the cytoplasm. Both antagonistic anti-Fas antibody ZB4 and pan-caspase inhibitor Z-VAD inhibited ZER-induced apoptosis in NB4 cells. Taken together, ZER is an inducer of apoptosis in leukemic cells that specifically triggers the Fas/CD95- and mitochondria-mediated apoptotic signaling pathway.
Xian
Mingji
M
Department of Internal Medicine, Division of Hematology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku Tokyo, 160-8582 Japan.
Ito
Keisuke
K
Nakazato
Tomonori
T
Shimizu
Takatsune
T
Chen
Chien-Kang
CK
Yamato
Kenji
K
Murakami
Akira
A
Ohigashi
Hajime
H
Ikeda
Yasuo
Y
Kizaki
Masahiro
M
D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D053148:Caspase 3 / Q000187:drug effects / Q000378:metabolism; D045744:Cell Line, Tumor; D053222:Fas Ligand Protein / Q000187:drug effects / Q000378:metabolism; D016195:G2 Phase / Q000187:drug effects; D006801:Humans; D007938:Leukemia / Q000188:drug therapy*; D008928:Mitochondria / Q000187:drug effects*; D012717:Sesquiterpenes / Q000494:pharmacology*; D019014:fas Receptor / Q000187:drug effects* / Q000378:metabolism
D000970:Antineoplastic Agents; D053222:Fas Ligand Protein; D012717:Sesquiterpenes; D019014:fas Receptor; C403304:zerumbone; D053148:Caspase 3