Interferon-gamma sensitizes resistant Ewing's sarcoma cells to tumor necrosis factor apoptosis-inducing ligand-induced apoptosis by up-regulation of caspase-8 without altering chemosensitivity.
Ewing's sarcoma cells are highly susceptible to apoptosis via tumor necrosis factor apoptosis-inducing ligand (TRAIL). Resistance to TRAIL has been linked to deficient expression of caspase-8 in vitro. Here, we report on the status of caspase-8 expression in tumors from patients with Ewing's sarcoma, the effect of interferon-gamma on caspase-8 expression and apoptosis, and the role of caspase-8 for TRAIL- and chemotherapy-mediated apoptosis in Ewing's sarcoma. Using immunohistochemistry, we show that low expression of caspase-8 is seen in about 24% of tumors. Interferon-gamma induces expression of caspase-8 at concentrations achievable in humans and sensitizes cells to TRAIL. Transfection of wild type but not mutant caspase-8 into caspase-8-deficient Ewing's sarcoma cells restored sensitivity to TRAIL, indicating that up-regulation of caspase-8 is sufficient to restore TRAIL sensitivity. In contrast, no role for caspase-8 in chemotherapy-induced apoptosis was identified, because 1) transfection of caspase-8 or treatment with interferon-gamma did not alter the sensitivity of caspase-8-deficient cells to chemotherapeutics, 2) application of chemotherapy did not select for caspase-8-negative tumor cells in vivo, and 3) the caspase-8 status of tumors did not influence survival after chemotherapy-based protocols. In conclusion, our data provide a rationale for the inclusion of interferon-gamma in upcoming clinical trials with TRAIL.
Lissat
Andrej
A
Division of Pediatric Hematology and Oncology, Department of Pediatrics and Adolescent Medicine, Albert-Ludwigs-University, Mathildenstrasse 1, 79106 Freiburg, Germany.
Vraetz
Thomas
T
Tsokos
Maria
M
Klein
Ruth
R
Braun
Matthias
M
Koutelia
Nino
N
Fisch
Paul
P
Romero
Maria E
ME
Long
Lauren
L
Noellke
Peter
P
Mackall
Crystal L
CL
Niemeyer
Charlotte M
CM
Kontny
Udo
U
D000293:Adolescent; D000328:Adult; D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000627:therapeutic use; D017209:Apoptosis / Q000502:physiology*; D001859:Bone Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D053181:Caspase 8 / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002648:Child; D004317:Doxorubicin / Q000627:therapeutic use; D019008:Drug Resistance, Neoplasm; D053595:Embryonic Stem Cells / Q000166:cytology / Q000502:physiology; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism* / Q000627:therapeutic use; D008297:Male; D012512:Sarcoma, Ewing / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D015996:Survival Rate; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000378:metabolism*; D015854:Up-Regulation
D000903:Antibiotics, Antineoplastic; D053221:TNF-Related Apoptosis-Inducing Ligand; D004317:Doxorubicin; D007371:Interferon-gamma; D053181:Caspase 8