Regulation of thyroid follicular cell function by intracellular redox-active copper.
Pyrrolidine dithiocarbamate (PDTC) is a metal-chelating compound that exerts prooxidant or antioxidant effects and is widely used to study redox regulation of cell function. In the present study, we investigated effects of PDTC on the function of rat thyroid follicular FRTL-5 cells. Treatment of the cells with PDTC resulted in a marked decrease in Pax-8 messenger RNA level and its DNA-binding activity. This decrease was associated with a significant reduction in thyroperoxidase (TPO) messenger RNA level. Expression of TTF-1 and thyroglobulin was not affected by PDTC. Treatment with PDTC also decreased DNA-binding activity of p53, a tumor suppressor protein, and increased cell proliferation rates. These changes were not observed by the treatment with another antioxidant, N-acetyl-L-cysteine, suggesting that the metal-chelating, prooxidant property of PDTC is responsible for its effects. Indeed, the intracellular level of copper was significantly increased by PDTC. Treatment with bathocuproinedisulfonic acid, a noncell-permeable chelator of Cu1+, abrogated the copper increase by PDTC and its effects on Pax-8 and TPO expression as well as on p53 binding. Taken together, these results indicate that the intracellular level of redox-active copper is crucial for Pax-8 and TPO expression and for proliferation of thyroid follicular cells.
Iseki
A
A
Department of Endocrinology and Metabolism, Research Institute of Environmental Medicine, Nagoya University, Japan.
Kambe
F
F
Okumura
K
K
Hayakawa
T
T
Seo
H
H
D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002614:Chelating Agents / Q000494:pharmacology; D003300:Copper / Q000378:metabolism*; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000378:metabolism; D007453:Iodide Peroxidase / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics; D010084:Oxidation-Reduction; D000072636:PAX8 Transcription Factor; D051761:Paired Box Transcription Factors; D010618:Phenanthrolines / Q000494:pharmacology; D011759:Pyrrolidines / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D013859:Thiocarbamates / Q000494:pharmacology; D013954:Thyroglobulin / Q000235:genetics; D013961:Thyroid Gland / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D000074482:Thyroid Nuclear Factor 1; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D000975:Antioxidants; D002614:Chelating Agents; D004268:DNA-Binding Proteins; C000614416:Nkx2-1 protein, rat; D009687:Nuclear Proteins; D000072636:PAX8 Transcription Factor; D051761:Paired Box Transcription Factors; C499497:Pax8 protein, rat; D010618:Phenanthrolines; D011759:Pyrrolidines; D012333:RNA, Messenger; D013859:Thiocarbamates; D000074482:Thyroid Nuclear Factor 1; D015534:Trans-Activators; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; C020972:pyrrolidine dithiocarbamic acid; C028559:bathocuproine sulfonate; D003300:Copper; D004247:DNA; D013954:Thyroglobulin; D006861:Hydrogen Peroxide; D007453:Iodide Peroxidase; D000111:Acetylcysteine