Proteasome inhibitor MG132 induces death receptor 5 through CCAAT/enhancer-binding protein homologous protein.
Combined treatment with a proteasome inhibitor and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising strategy for cancer therapy. Proteasome inhibitors induce the expression of death receptor 5 (DR5), a receptor for TRAIL, and sensitize cancer cells to TRAIL-induced apoptosis; however, the molecular mechanism of DR5 up-regulation has not been elucidated. In this study, we report that CCAAT/enhancer-binding protein homologous protein (CHOP) is a regulator of DR5 induction by proteasome inhibitor MG132. MG132 induced DR5 expression at a protein and mRNA level in prostate cancer DU145 cells. Furthermore, MG132 increased DR5 promoter activity. Using a series of deletion mutant plasmids containing DR5 promoters of various sizes, we found that MG132 stimulated the promoter activity via the region of -289 to -253. This region contained a CHOP-binding site. Site-directed mutation of the site abrogated the promoter activity enhanced by MG132. An electrophoretic mobility shift assay showed that CHOP directly bound to the MG132-responsive site on the DR5 promoter. Expression of the CHOP protein was increased with MG132 along with DR5 up-regulation. Furthermore, CHOP small interfering RNA attenuated the DR5 up-regulation due to MG132. These results indicate that the proteasome inhibitor MG132 induces DR5 expression through CHOP up-regulation.
Department of Molecular-Targeting Cancer Prevention, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kyoto, Japan.
Tatsushi
T
Yoshida
Takumi
T
Shiraishi
Susumu
S
Nakata
Mano
M
Horinaka
Miki
M
Wakada
Yoichi
Y
Mizutani
Tsuneharu
T
Miki
Toshiyuki
T
Sakai
D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D051017:Apoptosis Regulatory Proteins; D022762:CCAAT-Enhancer-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D045744:Cell Line, Tumor; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology*; D006801:Humans; D007976:Leupeptins / Q000494:pharmacology*; D008297:Male; D008562:Membrane Glycoproteins / Q000494:pharmacology; D016297:Mutagenesis, Site-Directed; D011401:Promoter Regions, Genetic / Q000187:drug effects; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D061988:Proteasome Inhibitors; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor / Q000096:biosynthesis* / Q000235:genetics; D053221:TNF-Related Apoptosis-Inducing Ligand; D051742:Transcription Factor CHOP; D014157:Transcription Factors / Q000378:metabolism / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology
D051017:Apoptosis Regulatory Proteins; D022762:CCAAT-Enhancer-Binding Proteins; D015853:Cysteine Proteinase Inhibitors; C497249:DDIT3 protein, human; D007976:Leupeptins; D008562:Membrane Glycoproteins; D061988:Proteasome Inhibitors; D012333:RNA, Messenger; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor; D053221:TNF-Related Apoptosis-Inducing Ligand; C505639:TNFRSF10B protein, human; C505653:TNFSF10 protein, human; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha; D051742:Transcription Factor CHOP; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde