TY - JOUR
T1 - Curcumin induces Apaf-1-dependent, p21-mediated caspase activation and apoptosis
AU - Gogada, Raghu
AU - Amadori, Michael
AU - Zhang, Honghao
AU - Jones, Anthony
AU - Verone, Alissa
AU - Pitarresi, Jason
AU - Jandhyam, Sirisha
AU - Prabhu, Varun
AU - Black, Jennifer D.
AU - Chandra, Dhyan
N1 - Funding Information:
We thank Drs. B. Vogelstein and Terry Beerman for providing reagents. This work was supported in part by a National Institutes of Health K01 Award CA123142 to D.C., NIH R01 award DK60632 and DK54909 to J.D.B. and National Cancer Institute Center Support Grant P30 CA016056 to the Roswell Park Cancer Institute. We apologize to those colleagues whose publications could not be cited due to space constraints.
PY - 2011/12/1
Y1 - 2011/12/1
N2 - Previous studies have demonstrated that curcumin induces mitochondria-mediated apoptosis. However, understanding of the molecular mechanisms underlying curcumin-induced cell death remains limited. In this study, we demonstrate that curcumin treatment of cancer cells caused dose- and time-dependent caspase 3 activation, which is required for apoptosis as confirmed using the pan-caspase inhibitor, z-VAD. Knockdown experiments and knockout cells excluded a role for caspase 8 in curcumin-induced caspase 3 activation. In contrast, Apaf-1 deficiency or silencing inhibited the activity of caspase 3, pointing to a requisite role of Apaf-1 in curcumin-induced apoptotic cell death. Curcumin treatment led to Apaf-1 upregulation, both at the protein and mRNA levels. Cytochrome c release from mitochondria to the cytosol in curcumin-treated cells was associated with upregulation of pro-apoptotic proteins, such as Bax, Bak, Bid and Bim. Cross-linking experiments demonstrated Bax oligomerization during curcumin-induced apoptosis, suggesting that induced expression of Bax, Bid and Bim causes Bax channel formation on the mitochondrial membrane. The release of cytochrome c was unaltered in p53-deficient cells, whereas absence of p21 blocked cytochrome c release, caspase activation and apoptosis. Importantly, p21 deficiency resulted in reduced expression of Apaf-1 during curcumin treatment, indicating a requirement for p21 in Apaf-1-dependent caspase activation and apoptosis. Together, our findings identify Apaf-1, Bax and p21 as novel potential targets for curcumin or curcumin-based anticancer agents.
AB - Previous studies have demonstrated that curcumin induces mitochondria-mediated apoptosis. However, understanding of the molecular mechanisms underlying curcumin-induced cell death remains limited. In this study, we demonstrate that curcumin treatment of cancer cells caused dose- and time-dependent caspase 3 activation, which is required for apoptosis as confirmed using the pan-caspase inhibitor, z-VAD. Knockdown experiments and knockout cells excluded a role for caspase 8 in curcumin-induced caspase 3 activation. In contrast, Apaf-1 deficiency or silencing inhibited the activity of caspase 3, pointing to a requisite role of Apaf-1 in curcumin-induced apoptotic cell death. Curcumin treatment led to Apaf-1 upregulation, both at the protein and mRNA levels. Cytochrome c release from mitochondria to the cytosol in curcumin-treated cells was associated with upregulation of pro-apoptotic proteins, such as Bax, Bak, Bid and Bim. Cross-linking experiments demonstrated Bax oligomerization during curcumin-induced apoptosis, suggesting that induced expression of Bax, Bid and Bim causes Bax channel formation on the mitochondrial membrane. The release of cytochrome c was unaltered in p53-deficient cells, whereas absence of p21 blocked cytochrome c release, caspase activation and apoptosis. Importantly, p21 deficiency resulted in reduced expression of Apaf-1 during curcumin treatment, indicating a requirement for p21 in Apaf-1-dependent caspase activation and apoptosis. Together, our findings identify Apaf-1, Bax and p21 as novel potential targets for curcumin or curcumin-based anticancer agents.
KW - Apaf-1
KW - Caspase
KW - Curcumin
KW - Cytochrome c
KW - Mitochondria
KW - p21
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U2 - 10.4161/cc.10.23.18292
DO - 10.4161/cc.10.23.18292
M3 - Article
C2 - 22101335
AN - SCOPUS:82855181502
SN - 1538-4101
VL - 10
SP - 4128
EP - 4137
JO - Cell Cycle
JF - Cell Cycle
IS - 23
ER -