Induction of cyclooxygenase-2 in human endometrial stromal cells by malignant endometrial epithelial cells: evidence for the involvement of extracellularly regulated kinases and CCAAT/enhancer binding proteins.
We previously reported that human malignant endometrial epithelial cell conditioned medium (MECM) up-regulated cyclooxygenase (COX)-2 mRNA and protein levels in human normal endometrial stromal cells (ESC). Here we showed that pretreatment with a selective inhibitor of the extracellularly regulated kinase (ERK)1/2 signaling pathway blocked the MECM-induced COX-2 expression in ESC. Transient transfection assays indicated critical roles of a cAMP response element (CRE,-59/-53 bp) and a nuclear factor for interleukin (IL)-6 expression (NF-IL6) site (-132/-124 bp) in the regulation of basal and MECM-induced activity of COX-2 gene promoter in ESC. Employing electrophoretic mobility shift assays, we demonstrated that increased functional binding of CCAAT/enhancer binding protein (C/EBP)alpha, C/EBPbeta and upstream stimulatory factor-2 to the CRE and C/EBPalpha and C/EBPbeta to the NF-IL6 site were, at least in part, responsible for MECM-induced COX-2 expression in ESC. Moreover, overexpression of C/EBPalpha and C/EBPbeta significantly induced COX-2 promoter activity in ESC. Collectively, these results suggest that the basal and MECM-induced transcription of the COX-2 gene in ESC is regulated through a combination of the CRE and the NF-IL6 site by functional interactions of C/EBPalpha and C/EBPbeta.
Tamura
M
M
Departments of Obstetrics and Gynecology, The University of Illinois at Chicago, Chicago, Illinois 60612, USA.
Sebastian
S
S
Yang
S
S
Gurates
B
B
Fang
Z
Z
Okamura
K
K
Bulun
S E
SE
D001483:Base Sequence; D022762:CCAAT-Enhancer-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D017077:Culture Media, Conditioned; D051546:Cyclooxygenase 2; D016889:Endometrial Neoplasms / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D004790:Enzyme Induction; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis / Q000235:genetics*; D008565:Membrane Proteins; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D016296:Mutagenesis; D015345:Oligonucleotide Probes; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis / Q000235:genetics*; D015183:Restriction Mapping; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017384:Sequence Deletion; D017154:Stromal Cells / Q000166:cytology / Q000201:enzymology / Q000473:pathology; D014162:Transfection; D014407:Tumor Cells, Cultured
D022762:CCAAT-Enhancer-Binding Proteins; D017077:Culture Media, Conditioned; D007527:Isoenzymes; D008565:Membrane Proteins; D015345:Oligonucleotide Probes; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D020928:Mitogen-Activated Protein Kinases