Tunicamycin enhances the apoptosis induced by tumor necrosis factor-related apoptosis-inducing ligand in endometriotic stromal cells.
BACKGROUND
The increase in concentration of osteoprotegerin, an antagonist of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), in the peritoneal fluid of women with endometriosis may interfere with TRAIL-induced apoptosis in endometriotic cells and promote the development of endometriosis. In the present study, the effect of tunicamycin, a possible apoptosis enhancer, on TRAIL-induced apoptosis in endometriotic stromal cells (ESC) was determined.


METHODS
ESC were isolated from cyst walls of ovarian endometrioma and cultured. ESC were incubated with or without tunicamycin (2 microg/ml) for the first 16 h, and then incubated with or without TRAIL (200 ng/ml) for the following 24 h. To examine whether caspases were involved in TRAIL-induced apoptosis, z-VAD-fmk (30 microM), a general caspase inhibitor, was added 1 h before TRAIL treatment. ESC were transfected with small interfering RNA (siRNA) for DR5, a receptor of TRAIL, before tunicamycin treatment to evaluate its role in ESC. DR5 mRNA level was determined by quantitative RT-PCR. Apoptosis in ESC was evaluated by flow cytometry.


RESULTS
Tunicamycin increases both DR5 mRNA (P < 0.005) and TRAIL-induced apoptosis (P < 0.0001) in ESC. The increase in TRAIL-induced apoptosis in ESC by tunicamycin was suppressed (P < 0.05) by z-VAD-fmk. Transfection with DR5 siRNA suppressed the tunicamycin-induced increase in DR5 mRNA and abrogated the up-regulation of TRAIL-induced apoptosis by tunicamycin.


CONCLUSIONS
The combined treatment with tunicamycin and TRAIL may have therapeutic potential in the treatment of endometriosis.
Hasegawa
Akiko
A
Department of Obstetrics and Gynecology, Faculty of Medicine, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
Osuga
Yutaka
Y
Hirota
Yasushi
Y
Hamasaki
Kahori
K
Kodama
Ako
A
Harada
Miyuki
M
Tajima
Toshiki
T
Takemura
Yuri
Y
Hirata
Tetsuya
T
Yoshino
Osamu
O
Koga
Kaori
K
Yano
Tetsu
T
Taketani
Yuji
Y
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002478:Cells, Cultured; D004715:Endometriosis / Q000473:pathology*; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand / Q000235:genetics / Q000378:metabolism; D017154:Stromal Cells / Q000187:drug effects* / Q000473:pathology; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000502:physiology*; D014415:Tunicamycin / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D012333:RNA, Messenger; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D053221:TNF-Related Apoptosis-Inducing Ligand; D014415:Tunicamycin