TY - JOUR
T1 - Role of tumor necrosis factor-related apoptosis-inducing ligand in interferon-induced apoptosis in human bladder cancer cells
AU - Papageorgiou, Angela
AU - Lashinger, Laura
AU - Millikan, Randall
AU - Grossman, H. Barton
AU - Benedict, William
AU - Dinney, Colin P.N.
AU - McConkey, David J.
PY - 2004/12/15
Y1 - 2004/12/15
N2 - Immunomodulators such as Bacillus Calmette-Guerin and interferon are clinically active in transitional cell carcinoma of the bladder, but their mechanisms of action remain unclear. Here we investigated the effects of IFNα on tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) expression and apoptosis in a panel of 20 human bladder cancer cell lines. Six (30%) displayed significant DNA fragmentation in response to increasing concentrations of IFNα (10-100,000 units/mL). In these lines IFNα induced early activation of caspase-8, and DNA fragmentation was blocked by a caspase-8-selective inhibitor (IETDfmk), consistent with the involvement of death receptor(s) in cell death. IFNα stimulated marked increases in TRAIL mRNA and protein in the majority of IFN-sensitive and IFN-resistant cell lines. A blocking anti-TRAIL antibody significantly inhibited IFN-induced DNA fragmentation in four of six IFN-sensitive cell lines, confirming that TRAIL played a direct role in cell death. Bortezomib (PS-341, Velcade), a potent TRAIL-sensitizing agent, increased sensitivity to IFNα in two of the IFN-resistant cell lines that produced large amounts of TRAIL in response to IFN treatment. Our data show that IFN-induced apoptosis in bladder cancer cells frequently involves autocrine TRAIL production. Combination therapy strategies aimed at overcoming TRAIL resistance may be very effective in restoring IFN sensitivity in a subset of human bladder tumors.
AB - Immunomodulators such as Bacillus Calmette-Guerin and interferon are clinically active in transitional cell carcinoma of the bladder, but their mechanisms of action remain unclear. Here we investigated the effects of IFNα on tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) expression and apoptosis in a panel of 20 human bladder cancer cell lines. Six (30%) displayed significant DNA fragmentation in response to increasing concentrations of IFNα (10-100,000 units/mL). In these lines IFNα induced early activation of caspase-8, and DNA fragmentation was blocked by a caspase-8-selective inhibitor (IETDfmk), consistent with the involvement of death receptor(s) in cell death. IFNα stimulated marked increases in TRAIL mRNA and protein in the majority of IFN-sensitive and IFN-resistant cell lines. A blocking anti-TRAIL antibody significantly inhibited IFN-induced DNA fragmentation in four of six IFN-sensitive cell lines, confirming that TRAIL played a direct role in cell death. Bortezomib (PS-341, Velcade), a potent TRAIL-sensitizing agent, increased sensitivity to IFNα in two of the IFN-resistant cell lines that produced large amounts of TRAIL in response to IFN treatment. Our data show that IFN-induced apoptosis in bladder cancer cells frequently involves autocrine TRAIL production. Combination therapy strategies aimed at overcoming TRAIL resistance may be very effective in restoring IFN sensitivity in a subset of human bladder tumors.
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U2 - 10.1158/0008-5472.CAN-04-1909
DO - 10.1158/0008-5472.CAN-04-1909
M3 - Article
C2 - 15604261
AN - SCOPUS:10844219883
SN - 0008-5472
VL - 64
SP - 8973
EP - 8979
JO - Cancer Research
JF - Cancer Research
IS - 24
ER -