Thyroid: Iodine Beyond the Thyronines

Although thyroid gland function is mainly under the control of pituitary TSH, other factors may also play a role in this process. Iodine is not used only by the thyroid to synthesize thyroid hormones but also directly influences a number of parameters such as thyroid proliferation and function. Thyroid autoregulation has been related to intraglandular content of an unknown putative iodocompound. The thyroid is capable of producing different iodolipids such as 6-iododeltalactone (IL ) and 2-iodohexadecanal (2-IHDA). Data from different laboratories have shown that these iodolipids can inhibit several thyroid parameters suggesting that these compounds may be the intermediates in the thyroid autoregulation process.Fil: Juvenal, Guillermo Juan. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. División Bioquímica Nuclear; ArgentinaFil: Thomasz, Lisa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. División Bioquímica Nuclear; ArgentinaFil: Oglio, Andrea Romina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. División Bioquímica Nuclear; ArgentinaFil: Perona, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. División Bioquímica Nuclear; ArgentinaFil: Pisarev, Mario Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. División Bioquímica Nuclear; ArgentinaFil: Rossich, Luciano Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. División Bioquímica Nuclear; ArgentinaFil: Salvarredi, Leonardo Andres. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. División Bioquímica Nuclear; Argentin

Comparative effects of transforming growth factor beta isoforms on redox metabolism in thyroid cells

Introduction: Transforming growth factor beta (TGF-β) regulates thyroid function and growth. However, tumoral thyroid cells became resistant to this factor as they undifferentiated. Little is known about the effects of TGF-β isoforms. We compared the role of redox metabolism in the response to TGF-β isoforms between non tumoral and tumoral thyroid cells. Methodology and results: Differentiated rat thyroid cells (FRTL-5) and human thyroid follicular carcinoma cells (WRO) were treated with the three isoforms of TGF-β. TGF-β isoforms stopped cell cycle at different steps; G1 for FRTL-5 and G2/M for WRO. The three isoforms decreased cell viability and increased ROS accumulation in both cell lines. These effects were more pronounced in FRTL-5 than in WRO, and the isoform β1 was more potent in ROS production than the other two. TGF-β isoforms decreased total glutathione, catalase expression and it activity in both cell lines. Only in FRTL-5 the lipid peroxidation was demonstrated. Moreover, TGF-β1 decreased glutathione peroxidase and mitochondrial superoxide dismutase mRNA expression and increased mitochondrial ROS in FRTL-5, but no in WRO. Pretreatment with selenium increased glutathione peroxidase activity and decreased ROS production in WRO treated with TGF-β isoforms. Furthermore, selenium partially reversed the effect of TGF-β isoforms on cell viability only in WRO cells. The knockdown of endogenous NOX4 significantly reduced the TGF-β1 effect on cell viability in WRO but no in FRTL-5. Conclusion: TGF-β disrupted the redox balance and increased ROS accumulation in both cell lines. FRTL-5 cells showed reduced antioxidant capacity and had a greater sensitivity to TGF-β isoforms, while WRO cells were more resistant. This observation provides new insights into the potential role of TGF-β in the redox regulation of thyroid cells.Fil: Oglio, Andrea Romina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. División Bioquímica Nuclear; ArgentinaFil: Thomasz, Lisa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. División Bioquímica Nuclear; ArgentinaFil: Salvarredi, Leonardo Andres. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. División Bioquímica Nuclear; ArgentinaFil: Juvenal, Guillermo Juan. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. División Bioquímica Nuclear; ArgentinaFil: Pisarev, Mario Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina; Argentin

Biochemical changes during goiter induction by methylmercaptoimidazol and inhibition by δ-iodolactone in rat

Background: We have demonstrated that the administration of δ-iodolactone (i.e., 5-iodo-delta lactone) of arachidonic acid (IL-δ), a mediator in thyroid autoregulation, prevents goiter induction by methylmercaptoimidazol (MMI) in rats. Other studies have shown that transforming growth factor beta-1 (TGF-β1) mimics some of the actions of excess iodide, but its participation in autoregulation is disputed. The present studies were performed to test the hypotheses that IL-δ decreases thyroid growth by inhibition of cell proliferation and/or by stimulation of apoptosis due to oxidative stress, that TGF-β is stimulated by an excess of iodide and by IL-δ, and that c-Myc and c-Fos expression are upregulated during goiter induction and downregulated during goiter inhibition. Methods: Rats were treated with MMI alone or together with iodide or IL-δ. Thyroid weight, cell number, cell proliferation, apoptosis, and oxidative stress were determined. Proliferating cell nuclear antigen (PCNA), TGF-β1, TGF-β3, c-Myc, and c-Fos were measured by Western blot. Results: MMI caused a progressive increase in thyroid weight accompanied by an increase in cell number, asymmetry of the ploidy histograms, and PCNA, c-Fos, and c-Myc expression. In addition, an early increase of apoptosis was observed. Peroxides as well as glutathione peroxidase and catalase activities were also increased in goitrous animals. The inhibitory action of IL-δ on goiter formation was accompanied by the inhibition of cell proliferation evidenced by a significant decrease in cell number, PCNA expression, and asymmetry of the ploidy histograms. A transient stimulation of apoptosis after 7 days of treatment was also observed. MMI administration stimulated TGF-β1 but not TGF-β3 synthesis. IL-δ alone caused a slight increase of TGF-β3 but not TGF-β1, whereas potassium iodide (KI) stimulated both isoforms and MMI reversed KI effect on TGF-β1 expression but not on TGF-β3. Conclusions: The goiter inhibitory action of IL-δ is due to the inhibition of cell proliferation and the transient stimulation of apoptosis. This latter action does not involve oxidative stress. TGF-β1 does not play a role in the autoregulatory pathway mediated by IL-δ. Iodide stimulates TGF-β3 without the need of being organified. These results suggest that there may be more than one pathway involved in the autoregulatory mechanism.Fil: Thomasz, Lisa. Comision Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. División Bioquímica Nuclear; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Oglio, Andrea Romina. Comision Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. División Bioquímica Nuclear; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Randi, Andrea Silvana. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Bioquímica Humana; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fernandez, Marina Olga. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Dagrosa, Maria Alejandra. Comision Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. División Bioquímica Nuclear; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cabrini, Romulo L.. Comision Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. División Bioquímica Nuclear; ArgentinaFil: Juvenal, Guillermo Juan. Comision Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. División Bioquímica Nuclear; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pisarev, Mario Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina. Comision Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. División Bioquímica Nuclear; Argentin

Regulation of NADPH oxidase NOX4 by delta iodolactone (IL-δ) in thyroid cancer cells

Introduction: Iodine is not used only by the thyroid to synthesize thyroid hormones but also directly influences a number of thyroid parameters such as thyroid proliferation and function. Several iodinated lipids, biosynthesized by the thyroid, were postulated as intermediaries in the action of iodide. Among these, iodolactone (IL-δ) and 2-iodohexadecanal (2-IHDA) have shown to inhibit several thyroid parameters. The antiproliferative effect of IL-δ is not restricted to the thyroid gland. IL-δ exhibits anti-tumor properties in breast cancer, neuroblastoma, glioblastoma, melanoma and lung carcinoma cells suggesting that IL-δ could be used as a chemotherapeutic agent. Moreover in a colon cancer cell line (HT-29), IL-δ induced cell death, and this effect was mediated by reactive oxygen species (ROS) generation. The aim of the present study was to analyze the sources of reactive oxygen species induced by IL-δ and to explore the contribution of ROS induced by IL-δ on cell proliferation and apoptosis. Methodology and results: Cancer thyroid follicular (WRO) and papilar (TPC-1) cells lines were treated with IL-δ. Proliferation and apoptosis was analyzed. IL-δ caused a significant loss of cell viability on WRO and TPC-1 cells in a concentration dependent manner and induced apoptosis after 3 h of treatment. Furthermore, IL-δ (10 μM) increased ROS production (39% WRO and 20% TPC-1). The concomitant treatment of WRO and TPC-1 cells with Trolox or NAC plus IL-δ abrogated the augment of ROS induced by IL-δ exposure. Additionally Trolox and NAC reversed the effect of IL-δ on cell proliferation and apoptosis. Only in WRO cells IL-δ upregulates NADPH oxidase NOX4 expression, and siRNA targeted knock-down of NOX4 attenuates ROS production, apoptosis (p < 0.05) and the inhibitory effect of IL-δ on cell proliferation and PCNA expression (p < 0.05). Conclusions: The antiproliferative and pro-apoptotic effect of IL-δ is mediated by different mechanisms and pathway involving different sources of ROS generation depending on the cellular context.Fil: Thomasz, Lisa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comision Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. División Bioquímica Nuclear; ArgentinaFil: Oglio, Andrea Romina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comision Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. División Bioquímica Nuclear; ArgentinaFil: Salvarredi, Leonardo Andres. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comision Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. División Bioquímica Nuclear; ArgentinaFil: Perona, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comision Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. División Bioquímica Nuclear; ArgentinaFil: Rossich, Luciano Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comision Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. División Bioquímica Nuclear; ArgentinaFil: Copelli, Silvia Beatriz. Universidad Centro de Altos Estudios en Ciencias Exactas; ArgentinaFil: Pisarev, Mario Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comision Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. División Bioquímica Nuclear; ArgentinaFil: Juvenal, Guillermo Juan. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comision Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. División Bioquímica Nuclear; Argentin

6 Iodo-d-lactone: A derivative of arachidonic acid with antitumor effects in HT-29 colon cancer cells

Background: IL-δ (5-hydroxy-6 iodo-8, 11, 14-eicosatrienoic delta lactone) an iodinated arachidonic acid (AA) derivative, is one of the iodolipids biosynthesized by the thyroid. Although IL-δ regulates several thyroid parameters such as cell proliferation and goiter growth it was found that this iodolipid inhibits the growth of other non thyroid cell lines. Objectives: to study the effect of IL-δ on cell proliferation and apoptosis in the colon cancer cell line HT-29. Results: Treatment with IL-δ reduced cell viability in a concentration-dependent manner: 1μM 20%, 5 μM 25%, 10 μM 31 %, 50 μM 47% and caused a significant decrease of PCNA expression (25%). IL-δ had pro-apoptotic effects, evidenced by morphological features of programmed cell death such as: pyknosis, karyorrhexis, cell shrinkage and cell blebbing observed by fluorescence microscopy, an increase in caspase-3 activity and in Bax/Bcl-2 ratio (2.5 after 3 h of treatment). Furthermore, IL-δ increased ROS production (30%) and lipid peroxidation levels (19 %), suggesting that apoptosis could be a result of increased oxidative stress. A maximum increase in c-fos and c-jun protein expression in response to IL-δ was observed 1 h after initiation of the treatment. Treatment with IL-δ blocked HT-29 xenografts growth in nude mice by more than 70% compared with the control group. Conclusion: our study shows that IL-δ inhibits cell growth and induces apoptosis in the colon cancer cell line, HT-29 and opens the possibility that IL-δ could be a potential useful chemotherapy agent.Fil: Thomasz, Lisa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Oglio, Andrea Romina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Rossich, Luciano Esteban. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Villamar, Sonia. Comisión Nacional de Energía Atómica; Argentina. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Perona, Marina. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Salvarredi, Leonardo Andres. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Dagrosa, María Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Pisarev, Mario Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Juvenal, Guillermo Juan. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin