Previous studies have shown that C cells are twice as numerous in male than in female thyroids and that C cell hyperplasia (CCH) is much more frequent in men. These findings suggest regulation involving sex steroid hormones through the expression of sex steroid hormone receptors on C cells. To investigate this hypothesis, we performed an immunohistochemical study of estrogen receptors alpha (ER alpha) and beta (ER beta), progesterone receptors (PR), and androgen receptors (AR) on specimens from a series of 40 patients operated on for a medullary thyroid carcinoma (MTC; n=28; female 18, male 10) and/or CCH (n=19; female 6, male 13). ER beta was the only receptor to be consistently expressed in CCH (100%) and MTC (96.5%), whereas ER alpha was never expressed. PR and AR were rarely expressed in MTC (7 and 14%, respectively). AR was expressed in half the CCH cases (53%), with a trend to male predominance (61% in men vs 33% in women). Our study is the first to describe ER beta expression in CCH. In addition, our findings suggest that CCH, and possibly MTC, might be influenced by sex steroid hormones, namely, estrogens and androgens, through the expression of ER beta and AR on C cells.
"More recently, a study showed that ERb was expressed in most of the MTC tissues (Blechet et al. 2007). However, immunohistochemistry results (Bur et al. 1993, Hiasa et al. 1993, Yane et al. 1993, Colomer et al. 1996, Lewy-Trenda 2002, Arain et al. 2003, Blechet et al. 2007) demonstrating ERa expression in thyroid tumors including follicular adenoma or carcinoma, papillary carcinoma, medullary carcinoma, and anaplastic carcinoma remain controversial depending on the antibody source. "
[Show abstract][Hide abstract] ABSTRACT: Medullary thyroid carcinoma (MTC) originates from parafollicular C cells. Estrogen receptor beta(ERbeta) expressionwas detected in normal parafollicular C cells and MTC tumor tissue, but ERalpha expression in MTC tumors still remains undetermined. The appearance and loss of ERalpha or ERbeta expression has been known to play a role in the development and progression of many human cancers. We performed immunohistochemical studies of ERalpha, ERbeta, and Ki67, a mitotic index, in 11 human MTC tissue samples. ERalpha was detected in 10 cases (91%), and ERbeta expression was observed in 8 cases (72.7%). A majority (8/10) of ERalpha-positive tumors showing ERbeta Ki67 expression was detected in three cases (27.3%). Neither clinical parameters nor tumor node metastasis (TNM) tumor staging was correlated with the positivity for ERs or Ki67. To investigate the biological role of each ER, we used ER-negative MTC TT cells and adenoviral vectors carrying ERalpha (Ad-ERalpha), ERbeta (Ad-ERbeta), estrogen response element (ERE)-Luc (Ad-ERE-Luc), and activator protein 1 (AP1)-Luc (Ad-AP1-Luc). Estrogen stimulated and anti-estrogen, ICI 182 780, suppressed ERE reporter activity in TT cells expressing ERalpha or ERbeta, suggesting that both ERs use the same classical ERE-mediated pathway. Ad-ERalpha infection stimulated TT cell growth; in contrast, Ad-ERbeta infection suppressed their growth. Apoptosis was detected in Ad-ERbeta-infected TT cells. Estrogen and anti-estrogen suppressed AP1 activity in Ad-ERalpha-infected cells, whereas upon Ad-ERbeta infection estrogen further stimulated AP1 activity which in turn is suppressed by anti-estrogen, suggesting that each ER acts differently through a non-ERE-mediated pathway. Our results suggest that ERalpha and ERbeta may play different roles in MTC tumor growth and progression.
Journal of Endocrinology 12/2007; 195(2):255-63. DOI:10.1677/JOE-06-0193 · 3.72 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A chronic feeding study to evaluate the safety of genetically modified glyphosate-tolerant soybeans (GM soybeans) was conducted using F344 DuCrj rats. The rats were fed diet containing GM soybeans or Non-GM soybeans at the concentration of 30% in basal diet. Non-GM soybeans were a closely related strain to the GM soybeans. These two diets werre adjusted to an identical nutrient level. In this study, the influence of GM soybeans in rats was compared with that of the Non-GM soybeans, and furthermore, to assess the effect of soybeans themselves, the groups of rats fed GM and Non-GM soybeans were compared with a group fed commercial diet (CE-2). General conditions were observed daily and body weight and food consumption were recorded. At the termination (104 weeks), animals were subjected to hematology, serum biochemistry, and pathological examinations. There were several differences in animal growth, food intake, organ weights and histological findings between the rats fed the GM and/or Non-GM soybeans and the rats fed CE-2. However, body weight and food intake were similar for the rats fed the GM and Non-GM soybeans. Gross necropsy findings, hematological and serum biochemical parameters, and organ weights showed no meaningful difference between rats fed the GM and Non-GM soybeans. In pathological observation, there was neither an increase in incidence nor any specific type of nonneoplastic or neoplastic lesions in the GM soybeans group in each sex. These results indicate that long-term intake of GM soybeans at the level of 30% in diet has no apparent adverse effect in rats.
Journal of the Food Hygienic Society of Japan (Shokuhin Eiseigaku Zasshi) 08/2008; 49(4):272-282. DOI:10.3358/shokueishi.49.272 · 0.25 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Thyroid cancer occurs three times more frequently in females than in males, and in females the incidence decreases after menopause. This gender difference suggests that the growth and progression of thyroid cancer may be influenced by female sex hormones, particularly estrogens. Experimental data have clearly demonstrated that estrogens can influence cancer cell growth. The action of estrogens on target sites is mediated through related but distinct estrogen receptors, designated estrogen receptor alpha (ERalpha) and estrogen receptor beta (ERbeta), both of which are known to be expressed in thyroid cancer cells. The proliferation of thyroid cancer cells is promoted by an ERalpha agonist, whereas the proliferation is reduced by the enhanced expression of ERbeta or by an ERbeta agonist. When ERbeta is down-regulated, the proliferation of thyroid cells is significantly increased. Studies have shown that the expression of ERalpha in thyroid cancer cells is increased while the expression of ERbeta is either very low or absent. In conclusion, it appears that estrogens have opposite effects on the growth of thyroid cancer cells, depending on the balance between ERalpha and ERbeta in the cells. The modulation of ERalpha and ERbeta and the intervention of their pathways may open up new potential targets for the treatment of thyroid cancer.
Current cancer drug targets 09/2008; 8(5):367-77. DOI:10.2174/156800908785133150 · 3.52 Impact Factor
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