Cell death induced by 131I in a differentiated thyroid carcinoma cell line in vitro: Necrosis or apoptosis?

The role of regulated necrosis in endocrine diseases

The death of endocrine cells is involved in type 1 diabetes mellitus, autoimmunity, adrenopause and hypogonadotropism. Insights from research on basic cell death have revealed that most pathophysiologically important cell death is necrotic in nature, whereas regular metabolism is maintained by apoptosis programmes. Necrosis is defined as cell death by plasma membrane rupture, which allows the release of damage-associated molecular patterns that trigger an immune response referred to as necroinflammation. Regulated necrosis comes in different forms, such as necroptosis, pyroptosis and ferroptosis. In this Perspective, with a focus on the endocrine environment, we introduce these cell death pathways and discuss the specific consequences of regulated necrosis. Given that clinical trials of necrostatins for the treatment of autoimmune conditions have already been initiated, we highlight the therapeutic potential of such novel therapeutic approaches that, in our opinion, should be tested in endocrine disorders in the future.

Network analysis reveals essential proteins that regulate sodium-iodide symporter expression in anaplastic thyroid carcinoma

Anaplastic thyroid carcinoma (ATC) is the most rare and lethal form of thyroid cancer and requires effective treatment. Efforts have been made to restore sodium-iodide symporter (NIS) expression in ATC cells where it has been downregulated, yet without complete success. Systems biology approaches have been used to simplify complex biological networks. Here, we attempt to find more suitable targets in order to restore NIS expression in ATC cells. We have built a simplified protein interaction network including transcription factors and proteins involved in MAPK, TGFβ/SMAD, PI3K/AKT, and TSHR signaling pathways which regulate NIS expression, alongside proteins interacting with them. The network was analyzed, and proteins were ranked based on several centrality indices. Our results suggest that the protein interaction network of NIS expression regulation is modular, and distance-based and information-flow-based centrality indices may be better predictors of important proteins in such networks. We propose that the high-ranked proteins found in our analysis are expected to be more promising targets in attempts to restore NIS expression in ATC cells.

The Effect of Resveratrol on Radioiodine Therapy-Associated Lacrimal Gland Damage

PURPOSE

We have evaluated the potential radioprotective, antioxidant and anti-apoptotic effects of resveratrol (RSV) against high-dose radioactive iodine (RAI) therapy associated damage of the lacrimal glands by biochemical, histopathological and immunohistochemical methods.

MATERIALS AND METHODS

Thirty Wistar-albino rats were randomly divided into three groups; the control group received no treatment or medication, the RAI group received RAI but no medication and the RSV group received oral RAI and intraperitoneal RSV. RSV was started at day one, before RAI administration, and continued for 8 days. Bilateral intraorbital (IG), extraorbital (EG), and Harderian (HG) lacrimal glands were evaluated in all rats for histopathological, immunohistochemical, tissue cytokine and oxidant and antioxidant level assessment.

RESULTS

RSV group restored inflammation, fibrosis, vacuolization, change in nucleus characteristics, lipofuscin-like accumulation and cellular morphologic patterns were statistically significant in all lacrimal gland types, compared to the RAI group (p < .05 for all variables). Similarly, elevated Caspase-3 and TUNEL levels in the RAI group were significantly alleviated in the RSV group in all lacrimal gland types (p < .05 for all variables). RAI administration significantly elevated TNF-α, IL-6, NF-кb levels, and decreased IL-10 levels (p < .05 for all parameters) whereas TOS levels significantly increased and TAS levels were significantly decreased. However, RSV significantly diminished TNF-α, IL-6, IL-4, and NF-кb levels. Furthermore, RSV significantly decreased TOS and increased TAS levels (p < .05 for all variables).

CONCLUSIONS

We conclude that with its anti-cancer effect as well as its antioxidant effect RSV has protected the histopathological pattern of the lacrimal glands from the damage, decreased inflammation in histopathologic assessments, and decreased tissue cytokine levels, apoptosis and DNA fragmentation on the lacrimal glands after RAI.

Apoptosis and cell proliferation in short-term and long-term effects of radioiodine-131-induced kidney damage: an experimental and immunohistochemical study

OBJECTIVE

Radioiodine-131 is a radionuclide that is used for therapeutic purposes in hyperthyroidism and thyroid cancer. The aim of this study was to evaluate apoptotosis and proliferative changes in radioiodine-related kidney damage.

MATERIALS AND METHODS

Three groups (n=10/group) of rats were used as follows: the rats were in group 1 untreated, and the rats in groups 2 and 3 were treated once with oral radioiodine (111 MBq). The animals in group 2 were killed at the end of the seventh day and the rats in group 3 were killed at the end of the 10th week. The kidneys were removed and evaluated immunohistochemically. The presence of radioiodine in the kidneys was shown by the Na+/I-symporter antibody and proliferating cell nuclear antigen, Ki-67, caspase-3, caspase-8, caspase-9, and terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end labeling assay were used to detect cell proliferation and apoptosis.

RESULTS

Na+/I-symporter protein accumulation in the kidneys was observed to be significantly greater in group 2 than in group 3 (P<0.05). All the immunohistochemical analyses showed that cell proliferation and apoptosis began on the seventh day and peaked in the 10th week. The proliferating cell nuclear antigen, Ki-67, and caspase expressions and terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end labeling values were all found to be statistically significantly increased in group 3 compared with the other groups (P<0.05).

CONCLUSION

Radioiodine caused cell proliferation and apoptosis as shown by immunohistochemistry.

Comparison of 30 mCi and 50 mCi I-131 doses for ablation of thyroid remnant in papillary thyroid cancer patients

PURPOSE OF THE STUDY

To compare efficacy of thyroid remnant ablation using 30 mCi or 50 mCi 131-I in papillary thyroid cancer patients.

MATERIALS AND METHODS

Five hundred and fifteen consecutive patients with Tumor-Node-Metastasis (TNM) stages T1-T3 N1/N0/NX receiving either 30 mCi or 50 mCi I-131 were analyzed for the effectiveness of remnant ablation using rhTSH-stimulated serum thyroglobulin. One hundred and five consecutive patients receiving 100 mCi I-131 were analyzed for the incidence of radiation thyroiditis and sialadenitis.

RESULTS AND CONCLUSIONS

Doses of 30 mCi and 50 mCi were equally effective for low- and moderate-risk disease but 30 mCi was less effective for T1T2NX disease, and 50 mCi was less effective for T3 compared to T1T2 disease. Low dose radiation hypersensitivity or unknown more extensive disease may have accounted for observed differences. Radiation thyroiditis and sialadenitis were more common in a comparison series of 100 mCi dose compared to 30 mCi, but not more common than in 50 mCi doses.

Small activating RNA upregulates NIS expression: promising potential for hepatocellular carcinoma endoradiotherapy

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide. Currently, the clinical strategies available for the treatment of HCC remain insufficient for the poor prognosis. Sodium/iodide symporter (NIS)-based radioiodine therapy is proposed as a promising therapeutic strategy for the treatment of HCC. However, it is difficult for HCC cells to trap iodine for the lower expression of NIS. Small activating RNA (saRNA) is a newly identified small double-stranded RNA (dsRNA) that can induce endogenous gene expression by targeting promoter sequences. Here, we designed an saRNA (saRNA-482) that targeted the NIS promoter sequences. In the cultured HepG2 cells and Hep3B cells, the expressions of NIS were upregulated after transfection of saRNA-482. In addition, the uptake of ¹²⁵I increased in the cultured HepG2 and Hep3B cells transfected with saRNA-482. Furthermore, the cell viabilities were significantly inhibited in the saRNA-482-transfected HepG2 and Hep3B cells after ¹³¹I treatment. Meanwhile, the apoptosis of saRNA-482-transfected HepG2 and Hep3B cells significantly increased after ¹³¹I treatment. The results suggest that RNA activation-mediated upregulation of NIS may have an endoradiotherapeutic potential in the treatment of HCC.

Iodine-131 induces apoptosis in HTori-3 human thyrocyte cell line and G2/M phase arrest in a p53-independent pathway

Iodine‑131 is known to destroy residual thyroid tissue following surgical resection of differentiated thyroid carcinoma and is widely used to treat hyperthyroidism. However, the mechanism by which iodine‑131 induces apoptosis and cell cycle arrest in the human thyrocyte cell line, Htori‑3, remains to be elucidated. In the present study, the cytotoxic effect of iodine‑131 on the HTori‑3 cell line and the underlying mechanism of iodine‑131‑induced cell apoptosis were investigated. Cell viability was analyzed using an MTT assay, while cell apoptosis and cell cycle arrest were determined using flow cytometry. Reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) and western blot analyses were performed to determine the changes in the expression levels of p53, B‑cell lymphoma 2 (Bcl‑2), Fas and growth arrest and DNA damage‑inducible 45 (GADD45), following iodine‑131 treatment. The results demonstrated that iodine‑131 may inhibit HTori‑3 cell growth via cell apoptosis and G2/M phase arrest in a time‑ and dose‑dependent manner. The iodine‑131 dose required for 50% growth inhibition of HTori‑3 cell viability 48 h after treatment was 27.75±2.22 MBq/ml. Upregulation of Fas and downregulation of Bcl‑2 expression levels were observed following iodine‑131 treatment. The results of RT‑qPCR revealed an increase in the GADD45 mRNA expression following HTori‑3 cell exposure to iodine‑131. Notably, the mRNA and protein expression levels of p53 were not altered following iodine‑131 treatment. In conclusion, iodine‑131 may induce apoptosis in HTori‑3 cells by downregulating the expression of Bcl‑2 and upregulating the expression of Fas. In addition, iodine‑131 may upregulate GADD45 mRNA expression in HTori‑3 cells, resulting in G2/M phase arrest in a p53‑independent pathway.

Radioiodide induces apoptosis in human thyroid tissue in culture

Radioiodide ((131)I) is routinely used for the treatment of toxic adenoma, Graves' disease, and for ablation of thyroid remnant after thyroidectomy in patients with thyroid cancer. The toxic effects of ionizing radiations on living cells can be mediated by a necrotic and/or apoptotic process. The involvement of apoptosis in radiation-induced cell death in the thyrocytes has been questioned. The knowledge of the mechanisms that underlie the thyrocyte death in response to radiations can help to achieve a successful treatment with the lowest (131)I dose. We developed a method to study the effects of (131)I in human thyroid tissue in culture, by which we demonstrated that (131)I induces thyroid cell apoptosis. Human thyroid tissues of about 1 mm(3) were cultured in vitro and cell viability was determined up to 3 weeks by the MTT assay. Radioiodide added to the culture medium was actively taken up by the tissues. The occurrence of apoptosis in the thyrocytes was assessed by measuring the production of a caspase-cleavage fragment of cytokeratin 18 (M30) by an enzyme-linked immunoassay. Neither variation of cell number nor spontaneous apoptosis was revealed after 1 week of culture. (131)I added to the culture medium induced a dose-dependent and a time-dependent generation of M30 fragment. The apoptotic process was confirmed by the generation of caspase-3 and PARP cleavage products. These results demonstrate that (131)I induces apoptosis in human thyrocytes. Human thyroid tissue cultures may be useful to investigate the cell death pathways induced by (131)I.

Nuclear factor-kappa B inhibition can enhance apoptosis of differentiated thyroid cancer cells induced by 131I

Objective

To evaluate changes of nuclear factor-kappa B (NF-κB) during radioiodine 131 (¹³¹I) therapy and whether NF-κB inhibition could enhance ¹³¹I-induced apoptosis in differentiated thyroid cancer (DTC) cells in a synergistic manner.

Methods

Three human DTC cell lines were used. NF-κB inhibition was achieved by using a NF-κB inhibitor (Bay 11-7082) or by p65 siRNA transfection. Methyl-thiazolyl-tetrazolium assay was performed for cell viability assessment. DNA-binding assay, luciferase reporter assay, and Western blot were adopted to determine function and expression changes of NF-κB. Then NF-κB regulated anti-apoptotic factors XIAP, cIAP1, and Bcl-xL were measured. Apoptosis was analyzed by Western blot for caspase 3 and PARP, and by flow cytometry as well. An iodide uptake assay was performed to determine whether NF-κB inhibition could influence radioactive iodide uptake.

Results

The methyl-thiazolyl-tetrazolium assay showed significant decrease of viable cells by combination therapy than by mono-therapies. The DNA-binding assay and luciferase reporter assay showed enhanced NF-κB function and reporter gene activities due to ¹³¹I, yet significant suppression was achieved by NF-κB inhibition. Western blot proved ¹³¹I could increase nuclear NF-κB concentration, while NF-κB inhibition reduced NF-κB concentration. Western blot also demonstrated significant up-regulation of XIAP, cIAP1, and Bcl-xL after ¹³¹I therapy. And inhibition of NF-κB could significantly down-regulate these factors. Finally, synergism induced by combined therapy was displayed by significant enhancements of cleaved caspase 3 and PARP from Western blot, and of Annexin V positively staining from flow cytometry. The iodine uptake assay did not show significant changes when NF-κB was inhibited.

Conclusion

We demonstrated that ¹³¹I could induce NF-κB activation, which would attenuate ¹³¹I efficacy in DTC cells. NF-κB inhibition by Bay 11-7082 or by p65 siRNA transfection was effective in suppressing NF-κB regulated anti-apoptotic changes and in combined regimen apoptosis was achieved synergistically.