Mono-(2-ethylhexyl) phthalate induces NR4A subfamily and GIOT-1 gene expression, and suppresses CYP19 expression in human granulosa-like tumor cell line KGN.
The mechanism for transcriptional suppression of CYP19 by mono-ethylhexyl phthalate (MEHP) in a human ovarian granulosa cell line (KGN) was investigated. It is known that the CYP19 gene transcript in KGN cells predominantly includes exon PII among the 11 alternate exon I sequences. MEHP was found to significantly suppress Forskolin (FSK)-induced CYP19 gene transcription, CYP19 promoter II activity and CYP19 enzyme activity in a dose-dependent manner. Promoter assays using 5'-deleted promoter II reporter constructs suggested that the region important for responsiveness to MEHP exposure includes a putative CRE-like sequence and an SF-1 (NR5A1)/LRH-1 (NR5A2) binding sequence. Meanwhile, MEHP exposure rapidly and transiently induced nuclear receptor 4A (NR4A) mRNA, and gradually and continuously induced gonadotropin-inducible ovarian transcription factor-1 (GIOT-1; ZNF461) mRNA in KGN cells. The ectopic expression of NR4As and GIOT-1 suppressed promoter II activity, while among the NR4As expressed, only Nur77 (NR4A1) secondarily induced GIOT-1 mRNA expression. Based on these results, we believe that induction of the Nur77-GIOT-1 system by MEHP is involved in the transcriptional suppression of the CYP19 gene, and GIOT-1 may attenuate the promoter II activity due to suppression of SF-1 and/or LRH-1 transactivation in KGN cells.
Ohno
Shuji
S
Department of Biochemistry, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa, Tokyo 142-8501, Japan. ohno@hoshi.ac.jp
Yukinawa
Fumihiko
F
Noda
Mariko
M
Nakajin
Shizuo
S
D001141:Aromatase / Q000096:biosynthesis* / Q000235:genetics; D001665:Binding Sites; D045744:Cell Line, Tumor; D004051:Diethylhexyl Phthalate / Q000031:analogs & derivatives* / Q000633:toxicity; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D006107:Granulosa Cells / Q000187:drug effects / Q000201:enzymology*; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1 / Q000096:biosynthesis* / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000187:drug effects; D012313:RNA / Q000096:biosynthesis / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000096:biosynthesis* / Q000235:genetics; D015533:Transcriptional Activation / Q000187:drug effects; D014162:Transfection
D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D014157:Transcription Factors; C447181:ZNF461 protein, human; D012313:RNA; D004051:Diethylhexyl Phthalate; D008156:Luciferases; D001141:Aromatase; C016599:mono-(2-ethylhexyl)phthalate