TY - JOUR
T1 - NF-κb-dependent MnSOD expression protects adenocarcinoma cells from TNF-α-induced apoptosis
AU - Delhalle, Sylvie
AU - Deregowski, Valérie
AU - Benoit, Valérie
AU - Merville, Marie Paule
AU - Bours, Vincent
PY - 2002/5/30
Y1 - 2002/5/30
N2 - NF-κB is known to exert a cytoprotective action against TNF-α-induced apoptosis. To study the role of NF-κB in various TNF-α-treated epithelial cell lines, we generated stable transfectants overexpressing a mutated unresponsive form of the IκBα inhibitor (MT cells). As NF-κB prevented TNF-α-induced apoptosis in various epithelial cancer cell lines, we searched for NF-κB target gene products responsible for this difference of sensitivity. We observed an increased Bcl-XL expression level in OVCAR-3 cells compared with OVCAR-3 cells expressing a mutated IκBα inhibitor (MT cells). Induction of the antioxidant enzyme MnSOD was detected only in TNF-α-treated OVCAR, MCF7A/Z and HCT116 cells but not in MT cells. Moreover, reactive oxygen species were involved in TNF-α-induced apoptosis, as various antioxidants partially protected these cells from apoptosis. At last, transfection of the MnSOD cDNA in MT cells, which do not express this protein after TNF-α stimulation, partially restored resistance to TNF-α-induced cell death, as observed by clonogenic assays. However, transfection of the Bcl-XL cDNA did not induce any protective effect. Therefore, MnSOD expression is induced by NF-κB in epithelial cancer cells in response to TNF-α, and is at least partially responsible for their resistance to TNF-α-induced apoptosis, presumably through the clearance of death-inducing ROS.
AB - NF-κB is known to exert a cytoprotective action against TNF-α-induced apoptosis. To study the role of NF-κB in various TNF-α-treated epithelial cell lines, we generated stable transfectants overexpressing a mutated unresponsive form of the IκBα inhibitor (MT cells). As NF-κB prevented TNF-α-induced apoptosis in various epithelial cancer cell lines, we searched for NF-κB target gene products responsible for this difference of sensitivity. We observed an increased Bcl-XL expression level in OVCAR-3 cells compared with OVCAR-3 cells expressing a mutated IκBα inhibitor (MT cells). Induction of the antioxidant enzyme MnSOD was detected only in TNF-α-treated OVCAR, MCF7A/Z and HCT116 cells but not in MT cells. Moreover, reactive oxygen species were involved in TNF-α-induced apoptosis, as various antioxidants partially protected these cells from apoptosis. At last, transfection of the MnSOD cDNA in MT cells, which do not express this protein after TNF-α stimulation, partially restored resistance to TNF-α-induced cell death, as observed by clonogenic assays. However, transfection of the Bcl-XL cDNA did not induce any protective effect. Therefore, MnSOD expression is induced by NF-κB in epithelial cancer cells in response to TNF-α, and is at least partially responsible for their resistance to TNF-α-induced apoptosis, presumably through the clearance of death-inducing ROS.
KW - Apoptosis
KW - Cancer
KW - MnSOD
KW - NF-κB
KW - TNF-α
UR - http://www.scopus.com/inward/record.url?scp=85047685805&partnerID=8YFLogxK
U2 - 10.1038/sj.onc.1205489
DO - 10.1038/sj.onc.1205489
M3 - Article
C2 - 12032830
AN - SCOPUS:85047685805
SN - 0950-9232
VL - 21
SP - 3917
EP - 3924
JO - Oncogene
JF - Oncogene
IS - 24
ER -