TY - JOUR
T1 - Up-regulation of c-Jun-NH2-kinase pathway contributes to the induction of mitochondria-mediated apoptosis by α-tocopheryl succinate in human prostate cancer cells
AU - Zu, Ke
AU - Hawthorn, Lesleyann
AU - Ip, Clement
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2005/1
Y1 - 2005/1
N2 - Previously, α-tocopheryl succinate (α-TOS) has been reported to induce caspase-mediated apoptosis in PC-3 human prostate cancer cells. Caspase-9 was among several initiator caspases activated by α-TOS, suggesting a potential contribution of the intrinsic apoptotic pathway in mediating the response to α-TOS. Gene expression microarray was carried out as a screen to identify novel signaling molecules modulated by α-TOS, with a special focus on those known to play a role in mitochondria-mediated apoptosis. We discovered that Ask1, GADD45β, and Sek1, three key components of the stress-activated mitogen-activated protein kinase pathway, are novel targets of α-TOS. Western blot analysis showed increased levels of phospho-Sek1 and phospho-c-Jun-NH2-kinase (JNK) in addition to total Ask1, GADD45β, and Sek1. α-TOS also altered JNK-specific phosphorylation of Bcl-2 and Bim in a manner consistent with enhanced mitochondrial translocation of Bax and Bim. Because the expression level of most Bcl-2 family members remained unchanged, the posttranslational modification of Bcl-2 and Bim by JNK is likely to be a driving force in α-TOS activation of the intrinsic apoptotic pathway. Based on our findings, we propose working model to capture the salient features of the poptotic signaling circuitry of α-TOS.
AB - Previously, α-tocopheryl succinate (α-TOS) has been reported to induce caspase-mediated apoptosis in PC-3 human prostate cancer cells. Caspase-9 was among several initiator caspases activated by α-TOS, suggesting a potential contribution of the intrinsic apoptotic pathway in mediating the response to α-TOS. Gene expression microarray was carried out as a screen to identify novel signaling molecules modulated by α-TOS, with a special focus on those known to play a role in mitochondria-mediated apoptosis. We discovered that Ask1, GADD45β, and Sek1, three key components of the stress-activated mitogen-activated protein kinase pathway, are novel targets of α-TOS. Western blot analysis showed increased levels of phospho-Sek1 and phospho-c-Jun-NH2-kinase (JNK) in addition to total Ask1, GADD45β, and Sek1. α-TOS also altered JNK-specific phosphorylation of Bcl-2 and Bim in a manner consistent with enhanced mitochondrial translocation of Bax and Bim. Because the expression level of most Bcl-2 family members remained unchanged, the posttranslational modification of Bcl-2 and Bim by JNK is likely to be a driving force in α-TOS activation of the intrinsic apoptotic pathway. Based on our findings, we propose working model to capture the salient features of the poptotic signaling circuitry of α-TOS.
UR - http://www.scopus.com/inward/record.url?scp=13944274587&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=13944274587&partnerID=8YFLogxK
M3 - Article
C2 - 15657352
AN - SCOPUS:13944274587
SN - 1535-7163
VL - 4
SP - 43
EP - 50
JO - Molecular cancer therapeutics
JF - Molecular cancer therapeutics
IS - 1
ER -