title: Molecular mechanisms of 2, 3', 4, 4', 5-pentachlorobiphenyl-induced thyroid dysfunction in FRTL-5 cells.
abstract: Polychlorinated biphenyls (PCBs) can severely interfere with multiple animals and human systems. To explore the molecular mechanisms underlying 2, 3', 4, 4', 5- pentachlorobiphenyl (PCB118)-induced thyroid dysfunction, Fischer rat thyroid cell line-5(FRTL-5) cells were treated with either different concentrations of PCB118 or dimethyl sulfoxide (DMSO). The effects of PCB118 on FRTL-5 cells viability and apoptosis were assessed by using a Cell Counting Kit-8 assay and apoptosis assays, respectively. Quantitative real-time polymerase chain reaction was used to quantify protein kinase B (Akt), Forkhead box protein O3a (FoxO3a), and sodium/iodide symporter (NIS) mRNA expression levels. Western blotting was used to detect Akt, phospho-Akt (p-Akt), FoxO3a, phospho-FoxO3a (p-FoxO3a), and NIS protein levels. Luciferase reporter gene technology was used to detect the transcriptional activities of FoxO3a and NIS promoters. The effects of the constitutively active Akt (CA-Akt) and dominant-negative Akt (DN-Akt) plasmids on p-Akt, p-FoxO3a, and NIS levels were examined in PCB118-treated FRTL-5 cells. The effects of FoxO3a siRNA on FoxO3a, p-FoxO3a, and NIS protein levels were examined in the PCB118-treated FRTL-5 cells. The effects of pcDNA3 (plsmid vectors designed for high-level stable and transient expression in mammalian host)-FoxO3a on NIS promoter activity were examined in the PCB118-treated FRTL-5 cells. Our results indicated that relatively higher PCB118 concentrations can inhibit cell viability in a concentration- and time-dependent manner. Akt, p-Akt, and p-FoxO3a protein or mRNA levels increased significantly in PCB118-treated groups and NIS protein and mRNA levels decreased considerably compared with the control groups. FoxO3a promoter activity increased significantly, whereas NIS promoter activity decreased. These effects on p-FoxO3a and NIS could be decreased by the DN-Akt plasmid, enhanced by the CA-Akt plasmid, and blocked by FoxO3a siRNA. The overexpressed FoxO3a could reduce NIS promoter activity. Our results suggested that PCB118 induces thyroid cell dysfunction through the Akt/FoxO3a/NIS signaling pathway.
authors: Department of Endocrinology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors: Hui
authors: H
authors: Yang
authors: Department of Endocrinology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors: Huanhuan
authors: H
authors: Chen
authors: Department of Endocrinology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors: Hongwei
authors: H
authors: Guo
authors: Department of Endocrinology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors: Wen
authors: W
authors: Li
authors: Department of Endocrinology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors: Jinmei
authors: J
authors: Tang
authors: Department of Endocrinology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors: Bojin
authors: B
authors: Xu
authors: Department of Endocrinology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors: Minne
authors: M
authors: Sun
authors: Department of Gerontology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors: Guoxian
authors: G
authors: Ding
authors: Department of Endocrinology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors: Lin
authors: L
authors: Jiang
authors: Department of Endocrinology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors: Dai
authors: D
authors: Cui
authors: Department of Endocrinology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors: Xuqin
authors: X
authors: Zheng
authors: Department of Endocrinology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors: Yu
authors: Y
authors: Duan
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002460:Cell Line; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D015536:Down-Regulation / Q000187:drug effects; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation; D011078:Polychlorinated Biphenyls / Q000633:toxicity*; D011401:Promoter Regions, Genetic; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects; D027981:Symporters / Q000235:genetics / Q000378:metabolism; D013961:Thyroid Gland / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects; D000099209:Sodium-Iodide Symporters
chemical_list: D004121:Dimethyl Sulfoxide; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors; D019869:Phosphatidylinositol 3-Kinases; D011078:Polychlorinated Biphenyls; D051057:Proto-Oncogene Proteins c-akt; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D027981:Symporters; D000099209:Sodium-Iodide Symporters; C499515:FOXO3 protein, rat; C070055:2,3',4,4',5-pentachlorobiphenyl