Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P10415 (Bcl-2)
 33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Apoptosis is an active biologic process that represents a form of programmed cellular suicide, activated either by genetic factors or by cellular lesions caused by various extracellular traumatic agents. The alterations of its functional mechanisms control cellular homeostasis are involved in the genesis of many illnesses. There are different control systems that can both stimulate and inhibit apoptosis, such as the p53 and Bcl-2 proteins. Different injuries may cause a rapid increase in the levels of p53 and the activation of the complex mechanism which leads either to damage repair or cellular apoptosis. The concept of tumor growth as a dynamic balance between cellular development and death is well applicable to differentiated thyroid carcinomas, which are generally not highly invasive and present excellent prognosis. On the contrary, in aggressive anaplastic thyroid carcinoma there is an increase in p53, whereas in normal thyroid cells there is a high expression of Bcl-2, so as to interfere with apoptosis when physiologic hormone levels are normal. However, only some of the biomolecular mechanisms behind the genesis of thyroid tumors have been explained, and the role of apoptosis in thyroid diseases has not been well defined. This review provides information about relationship between apoptosis and thyroid diseases.
Thyroid 2002 Jan
PMID:Apoptosis: life through planned cellular death regulating mechanisms, control systems, and relations with thyroid diseases. 1183 27

Thyroid hormone (TH) deficiency results in delayed proliferation and migration of cerebellar granule cells. Although extensive cell loss during the development of the cerebellum under hypothyroid conditions is known, its nature and its mechanism are poorly understood. Bcl-2 family gene expression is known to determine the fate of cells to undergo apoptosis. We evaluated the effect of hypothyroidism on Bcl-2 family gene expression in the developing rat cerebellum. Electrophoresis and Western blotting were used to analyze DNA fragmentation and expression of DNA fragmentation factor (DFF-45), Bcl-2, Bcl-xL and Bax genes respectively. In the hypothyroid condition, extensive DNA fragmentation and enhanced cleavage of DFF-45 were seen throughout development (postnatal day 0 to day 24) and adulthood whereas they were absent in the euthyroid state. The anti-apoptotic genes Bcl-2 and Bcl-xL were down-regulated and the pro-apoptotic gene Bax was expressed at higher levels compared with the euthyroid state. These results suggest that normal levels of TH prevent cerebellar apoptosis to a large extent, whereas hypothyroidism not only increases the extent but also the duration of apoptosis by down-regulating the anti-apoptotic genes and maintaining a high level of the pro-apoptotic gene Bax.
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PMID:Hypothyroidism alters the expression of Bcl-2 family genes to induce enhanced apoptosis in the developing cerebellum. 1252 48

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in many human cancer cells but not in normal cells. Thyroid cancer cells, however, appear to be relatively resistant to TRAIL-induced apoptosis. We therefore investigated the effect of chemotherapy on TRAIL-induced apoptosis in thyroid cancer cells. We used six thyroid cancer cell lines: TPC-1, FTC-133, FTC-236, FTC-238, XTC-1, and ARO82-1. We used flow cytometry to measure apoptosis, dimethyl-thiazol-diphenyltetrazolium bromide (MTT) assay to measure antiproliferation effects and Western blot to determine the expression of Bcl family proteins. Troglitazone, paclitaxel, geldanamycin, and cycloheximide were used for pretreatment. We used the Student's t test and analysis of variance (ANOVA) for statistical analysis. All thyroid cancer cell lines, except the TPC-1 cell line, were resistant to TRAIL, and growth inhibition was less than 20% at concentration of 800 ng/mL of TRAIL. In both TPC-1 (TRAIL-sensitive) and FTC-133 (TRAIL-resistant) thyroid cancer cell lines, pretreatment with troglitazone, cycloheximide, and paclitaxel enhanced TRAIL-induced cell death significantly but pretreatment with geldanamycin did not. There were no significant changes in Bcl-2, Bcl-xl, and Bax protein expression after troglitazone treatment. In conclusion, TRAIL in combination with troglitazone, paclitaxel, and cycloheximide induces apoptosis in thyroid cancer cells at suboptimal concentrations that cannot be achieved using TRAIL alone.
Thyroid 2003 Dec
PMID:Modulation of tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis by chemotherapy in thyroid cancer cell lines. 1475 Oct 30

IL-4, a pleiotropic cytokine mainly produced by activated helper T lymphocytes type 2 (Th2), is known to protect thyroid cells from autoimmune damage. Acting via its receptors (IL-4Ralpha), IL-4 has antiproliferative and apoptotic effects in many malignancies. Its effect in thyroid cancer is unknown. We found that surgical specimens of thyroid carcinomas express both IL-4Ralpha and IL-4 in the majority of cases. Thyroid glands affected by Graves' disease also express IL-4. We also studied a panel of eight thyroid cancer cell lines from different histotypes and found that thyroid cancer cells express high levels of IL-4Ralpha although they do not express IL-4. We then compared the biological effects of IL-4 in TPC-1, a thyroid cancer cell line, and in MCF-7 breast cancer cells. IL-4 very weakly stimulated thyroid cancer cell proliferation, but it was very effective in protecting thyroid cancer cells from apoptosis induced by staurosporin. The protective effect of IL-4 was similar in magnitude to that of IGF-I and was associated with up-regulation of the antiapoptotic molecule Bcl-2 and weak down-regulation of the proapoptotic molecule Bax. Moreover, IL-4 slightly potentiated the survival effect of IGF-I. In contrast, IL-4 reduced growth and induced apoptosis in MCF-7 cells. Taken together, these findings suggest that thyroid cancer cells receive significant protection from apoptosis by IL-4 produced in the thyroid gland by activated T lymphocytes when concomitant Graves' disease is present.
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PMID:Interleukin-4 stimulates papillary thyroid cancer cell survival: implications in patients with thyroid cancer and concomitant Graves' disease. 1518 Oct 72

Thyroid hormone insufficiency adversely affects cortical development; however, its effect on apoptosis modulation during cerebral cortex development is not understood. We investigated the effect of perinatal hypothyroidism on apoptosis and its mechanisms during rat cerebral cortex development. Primary hypothyroidism was induced by feeding methimazole (0.025% wt/vol) in the drinking water to pregnant and lactating rats and continued until the animals were killed (hypothyroid group). Cerebral cortices from pups were harvested at different postnatal ages (postnatal d 0, 8, 16, and 24 and adult), and apoptosis was quantitated by terminal deoxynucleotide transferase-mediated dUTP nick end labeling and cleaved caspase-3 immunoreactivity. Compared with the euthyroid, primary somatosensory cortex (S1) in the hypothyroid group exhibited enhanced apoptosis. In S1 of euthyroid rats, apoptotic cells were mostly found in cortical layers I-III and the proportion of apoptotic cells enhanced significantly in the hypothyroid group (P < 0.001). Most of the apoptotic cells were neurons, as assessed by double immunolabeling. A significantly increased activation of caspase-3 and -7, decreased levels of antiapoptotic proteins Bcl-2 and Bcl-x(L), and increased levels of proapoptotic protein Bax was observed in the developing cerebral cortex of hypothyroid rats, compared with the euthyroid (P < 0.001). In addition, hypothyroidism significantly elevated the levels of 53-kDa pro-nerve growth factor (P < 0.001) and p75 neurotrophin receptor (P < 0.001) and decreased TrkA expression. Taken together, we provide evidence for the possible contribution of pro-nerve growth factor/p75 neurotrophin receptor pathway in hypothyroidism-enhanced apoptosis during rat cortical development. Thus, the present study may help in explaining the mechanism of the deleterious effect of thyroid hormone deficiency on cerebral cortex development in children.
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PMID:Increased pro-nerve growth factor and p75 neurotrophin receptor levels in developing hypothyroid rat cerebral cortex are associated with enhanced apoptosis. 1679 16

Thyroid hormone (TH, T3) is required for the normal function of most tissues, with major effects on O2 consumption and metabolic rate. These are due to transcriptional activation of respiratory genes through the interaction of T3-liganded TH receptors with TH response elements or the activation of intermediate factors, with the consequent higher rates of mitochondrial oxidative phosphorylation and reactive O2 species (ROS) generation and antioxidant depletion. The genomic effects of TH are accompanied by redox upregulation of the liver expression of cytokines (tumor necrosis factor-alpha [TNF-alpha]), enzymes (manganese superoxide dismutase), and anti-apoptotic proteins (Bcl-2), via a cascade initiated by TNF-alpha produced by Kupffer cells and involving inhibitor of kappa-B phosphorylation and nuclear factor-kappa-B activation. Thus, TH calorigenesis triggers non-genomic effects leading to an expression pattern that may represent an adaptive mechanism to re-establish redox homeostasis and promote cell survival under conditions of ROS toxicity secondary to TH-induced oxidative stress. Mechanisms of expression of respiratory and redox-sensitive genes may be functionally integrated, which could be of importance to understand the complexities of TH action and the outcome of thyroid gland dysfunction.
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PMID:Thyroid hormone calorigenesis and mitochondrial redox signaling: upregulation of gene expression. 1712 75

Thyroid hormone (TH; 3,3',5-triiodothyronine, T3) is required for the normal function of most tissues, with major effects on O(2) consumption and metabolic rate. These are due to transcriptional activation of respiratory genes through the interaction of T3-liganded TH receptors with TH response elements or the activation of intermediate factors, with the consequent higher production of reactive O(2) species (ROS) and antioxidant depletion. T3-induced oxidative stress in the liver triggers the redox upregulation of the expression of cytokines (tumor necrosis factor-alpha [TNF-alpha], interleukin-10), enzymes (inducible nitric oxide synthase, manganese superoxide dismutase), and anti-apoptotic proteins (Bcl-2), via a cascade initiated by TNF-alpha produced by Kupffer cells, involving inhibitor of kappaB phosphorylation and nuclear factor-kappaB activation. Thus, TH calorigenesis triggers an expression pattern that may represent an adaptive mechanism to re-establish redox homeostasis and promote cell survival under conditions of ROS toxicity secondary to TH-induced oxidative stress. Mechanisms of expression of respiratory and redox-sensitive genes may be functionally integrated, which could be of importance to understand the complexities of TH action and the outcome of thyroid gland dysfunction.
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PMID:The role of thyroid hormone calorigenesis in the redox regulation of gene expression. 1765 42

Thyroid hormone (T3) plays a crucial role in processes such as cell proliferation and differentiation, whereas its implication on cellular apoptosis has not been well documented. Here we examined the effect of T3 on the apoptosis of GH4C1 pituitary cells and the mechanisms underlying this effect. We show that T3 produced a significant increase in apoptosis in serum-depleted conditions. This effect was accompanied by a decrease in nuclear factor-kappaB (NF-kappaB)-dependent transcription, IkappaBalpha phosphorylation, translocation of p65/NF-kappaB to the nucleus, phosphorylation, and transactivation. Moreover, these effects were correlated with a T3-induced decrease in the expression of antiapoptotic gene products, such as members of the inhibitor of apoptosis protein and Bcl-2 families. On the other hand, ERK but not c-Jun N-terminal kinase or MAPK p38, was activated upon exposure to T3, and inhibition of ERK alone abrogated T3-mediated apoptosis. In addition, T3 increased the expression of the MAPK phosphatase, dual specificity phosphatase 1 (DUSP1), in an ERK-dependent manner. Interestingly, the suppression of DUSP1 expression abrogated T3-induced inhibition of NF-kappaB-dependent transcription and p65/NF-kappaB translocation to the nucleus, as well as T3-mediated apoptosis. Overall, our results indicate that T3 induces apoptosis in rat pituitary tumor cells by down-regulating NF-kappaB activity through a mechanism dependent on the ERK/DUSP1 pathway.
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PMID:Thyroid hormone-mediated activation of the ERK/dual specificity phosphatase 1 pathway augments the apoptosis of GH4C1 cells by down-regulating nuclear factor-kappaB activity. 1875 55

Thyroid hormone (L-3,3',5-triiodothyronine, T(3)) exerts calorigenic effects by accelerating mitochondrial O(2) consumption through transcriptional activation of respiratory genes, with consequent increased reactive oxygen species (ROS) production. In the liver, ROS generation occurs at different sites of hepatocytes and in the respiratory burst of Kupffer cells, triggering the activation of the transcription factors nuclear factor-kappaB, signal transducer and activator of transcription 3, and activating protein 1. Under these conditions, the redox upregulation of Kupffer cell-dependent expression of cytokines [tumor necrosis factor-alpha, interleukin (IL)-1, and IL-6] is achieved, which upon interaction with specific receptors in hepatocytes trigger the expression of antioxidant enzymes (manganese superoxide dismutase, inducible nitric oxide synthase), antiapoptotic proteins (Bcl-2), and acute-phase proteins (haptoglobin, beta-fibrinogen). These responses and the promotion of hepatocyte and Kupffer cell proliferation observed represent hormetic effects re-establishing redox homeostasis, promoting cell survival, and protecting the liver against ischemia-reperfusion (IR) injury. It is proposed that hormesis underlying T(3) action may constitute a novel preconditioning strategy for IR injury during liver surgery in man or in liver transplantation using reduced-size grafts from living donors, considering that (i) with the exception of the controversial ischemic preconditioning, all other studied strategies have failed to reach the clinical setting and (ii) T(3) is a well-tolerated therapeutic agent that either lacks major adverse effects or has minimal and controlled side effects.
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PMID:Hormetic responses of thyroid hormone calorigenesis in the liver: Association with oxidative stress. 2050 39

The aim was to assess changes of B and T lymphocytes and selected apoptotic markers in Hashimoto thyroiditis (HT) cases on the basis of quantitative immunohistochemical studies (CD20, CD43, CD8, Bcl-2, caspase-3). The control group comprised colloid goitres without inflammatory infiltrate taken from 10 female patients. Thyroid specimens were obtained retrospectively from 40 patients. The immunohistochemical reactions were subject to quantitative evaluation performed using image-processing methods, including a spatial visualisation of the markers' expression. The percentage of Bcl-2 reactions in HT (mean 3.65%, SD 2.94%) was significantly lower than in the control group (mean 13.99%, SD 5.04%), while the thyroid follicles in HT samples exhibited a higher degree of staining for caspase-3 (mean 1.10%, SD 1.03%) in contrast to normal control tissues (mean 0.48%, SD 1.02%). The results from this study indicate that apoptosis plays a major role in the patogenesis of autoimmune thyroid diseases containing the main pathogenic events in the lesion of thyroid follicular cells in HT. Moreover, the reactivity of CD43 and CD20 was significantly higher in Hashimoto disease, while CD8 was not significantly different from the control group.
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PMID:Changes of B and T lymphocytes and selected apopotosis markers in Hashimoto's thyroiditis. 2124 29


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