Thyroid hormone signaling in human ovarian surface epithelial cells

Hypothyroidism and hyperthyroidism related to gynecologic cancers: a nationwide population-based cohort study

The purpose of this study was to assess the risks of hyperthyroidism and hypothyroidism related to gynecological cancers. Population-based retrospective cohort study. We conducted a cohort study using the Taiwan National Health Insurance Research Database to explore hyperthyroidism and hypothyroidism associated with site-specific gynecologic cancers in women from January 1, 2000 to December 31, 2018. The examined gynecologic cancers included endometrial (EC), uterine corpus cancer (UC), and ovarian cancer (OC). The incidence and hazard ratios were quantified using Cox proportional hazards models. The incidence of developing gynecological (Gyn) cancers in the hyperthyroid and hypothyroid women was 0.29 and 0.44 per 1000 person-years, which was 0.86 fold lower and 1.13 fold higher than that in the comparison cohort (p < 0.001). Compared with patients aged 20-40 years, patients in older age groups had a lower and higher risk of developing Gyn cancers (for hyperthyroid, 40-65 years: adjusted hazard ratio (aHR) = 0.82; > 65 years: aHR = 0.94; for hypothyroid, adjusted hazard ratio (aHR) = 1.26; > 65 years: aHR = 1.38). Compared with the non-hypothyroid women and non-hyperthyroid women beyond 6 years of follow-up, hypothyroid and hyperthyroid women showed decreased risk of Gyn cancers. Medication treatment for hyperthyroid and hypothyroid disease did not showed significant association in subgroup analyses (aHR = 0.99 and 0.80, respectively). Our results show that women with hyperthyroidism have a significantly reduced risk of gynecological cancers, whereas women with hypothyroidism have a slightly increased risk of gynecological cancers suggesting an association between thyroid function level and risk of gynecological cancers.

Single-Cell Transcriptome Analysis Reveals Development-Specific Networks at Distinct Synchronized Antral Follicle Sizes in Sheep Oocytes

The development of the ovarian antral follicle is a complex, highly regulated process. Oocytes orchestrate and coordinate the development of mammalian ovarian follicles, and the rate of follicular development is governed by a developmental program intrinsic to the oocyte. Characterizing oocyte signatures during this dynamic process is critical for understanding oocyte maturation and follicular development. Although the transcriptional signature of sheep oocytes matured in vitro and preovulatory oocytes have been previously described, the transcriptional changes of oocytes in antral follicles have not. Here, we used single-cell transcriptomics (SmartSeq2) to characterize sheep oocytes from small, medium, and large antral follicles. We characterized the transcriptomic landscape of sheep oocytes during antral follicle development, identifying unique features in the transcriptional atlas, stage-specific molecular signatures, oocyte-secreted factors, and transcription factor networks. Notably, we identified the specific expression of 222 genes in the LO, 8 and 6 genes that were stage-specific in the MO and SO, respectively. We also elucidated signaling pathways in each antral follicle size that may reflect oocyte quality and in vitro maturation competency. Additionally, we discovered key biological processes that drive the transition from small to large antral follicles, revealing hub genes involved in follicle recruitment and selection. Thus, our work provides a comprehensive characterization of the single-oocyte transcriptome, filling a gap in the mapping of the molecular landscape of sheep oogenesis. We also provide key insights into the transcriptional regulation of the critical sizes of antral follicular development, which is essential for understanding how the oocyte orchestrates follicular development.

Hierarchies in the energy budget: Thyroid hormones and the evolution of human life history patterns

The evolution of human life history characteristics required dramatic shifts in energy allocation mechanisms compared with our primate ancestors. Thyroid hormones, such as thyroxine (T4) and triiodothyronine (T3), are sensitive to energy balance, and are significant determinants for both tissue-specific and whole-body metabolic rate. Thus, thyroid hormones are in part responsible for setting the body's overall energy budget and likely played an important role in the evolution of human life history patterns. We propose that the dynamics of mammalian T3 production, uptake, and action have evolved so that energy allocation prioritizes the high demands of brain development and functioning, often at the expense of growth and reproduction. This paper explores the role of thyroid hormone dynamics in the evolution of human encephalization, prolonged childhood and adolescence, long lifespans, reproduction, and human aging.

Relationship between thyroid antibody levels and ovarian reserve function in infertile chinese women with normal thyroid-stimulating hormone

BACKGROUND

To analyze the relationship of thyroid peroxidase antibody and thyroid globulin antibody levels with ovarian reserve function in infertile women.

METHODS

The data of 721 infertile patients who visited the hospital from January 2019 to September 2022 and whose thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) levels were in the normal range, were retrospectively analyzed. These patients were divided into two sets of three groups-the negative group, the 2.6 IU/ml ~ 100 IU/ml group and the TPOAb > 100 IU/ml group according to the TPOAb (thyroid peroxidase antibody) level, or the TgAb (anti-thyroglobulin antibody) negative group, the 14.58 IU/ml ~ 100 IU/ml group and the TgAb > 100 IU/ml group according to the TgAb level. They were compared for differences in ovarian reserve function index and thyroid hormone levels and analyzed for the relationship among thyroid antibody levels, ovarian reserve function, and thyroid hormone levels.

RESULTS

When TSH > 2.5 mIU/L, the bFSH (basal follicle stimulating hormone) level in the TPOAb > 100 IU/ml group (9.10 ± 1.16 IU/L) was significantly higher than that in the TPOAb negative group (8.12 ± 1.97 IU/L) and the 2.6 IU/ml ~ 100 IU/ml group (7.90 ± 1.48 IU/L) (P < 0.05); when TSH ≤ 2.5 mIU/L, there were no statistically significant differences in the bFSH and AFC (antral follicle count) number at different TPOAb levels. Whether TSH ≤ 2.5 mIU/L or TSH > 2.5 mIU/L, there were no statistically significant differences in the bFSH and AFC number at different TgAb levels (P > 0.05). FT3/FT4 ratio in the TPOAb 2.6 IU/ml ~ 100 IU/ml group and the > 100 IU/ml group was significantly lower than in the negative group. FT3/FT4 ratio in the TgAb 14.58 ~ 100 IU/ml group and the > 100 IU/ml group was also significantly lower than in the TgAb negative group (P < 0.05). TSH level in the TPOAb > 100 IU/ml group was significantly higher than in the 2.6 ~ 100 IU/ml group and the TPOAb negative group, but there were no statistically significant differences among different TgAb groups.

CONCLUSIONS

When TPOAb > 100 IU/ml and TSH > 2.5 mIU/L, it may affect the ovarian reserve function in infertile patients, and the mechanism may be associated with increased TSH and the imbalance of FT3/FT4 ratio caused by the increase of TPOAb.

Metabolic pathways of potential miRNA biomarkers derived from liquid biopsy in epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is the type of OC with the highest mortality rate. Due to the asymptomatic nature of the disease and few available diagnostic tests, it is mostly diagnosed at the advanced stage. Therefore, the present study aimed to discover predictive and/or early diagnostic novel circulating microRNAs (miRNAs or miRs) for EOC. Firstly, microarray analysis of miRNA expression levels was performed on 32 samples of female individuals: Eight plasma samples from patients with pathologically confirmed EOC (mean age, 45 (30-54) years), eight plasma samples from matched healthy individuals (HIs) (mean age, 44 (30-65) years), eight EOC tissue samples (mean age, 45 (30-54) years) and eight benign ovarian (mean age, 35 (17-70) years) neoplastic tissue samples A total of 31 significantly dysregulated miRNAs in serum and three miRNAs in tissue were identified by microarray. The results were validated using reverse transcription-quantitative PCR on samples from 10 patients with pathologically confirmed EOC (mean age, 47(30-54) years), 10 matched His (mean age, 40(26-65) years], 10 EOC tissue samples (mean age, 47(30-54) years) and 10 benign ovarian neoplastic tissue samples (mean age, 40(17-70) years). The 'Kyoto Encyclopedia of Genes and Genomes' (KEGG) database was used for target gene and pathway analysis. A total of three miRNAs from EOC serum (hsa-miR-1909-5p, hsa-miR-885-5p and hsa-let-7d-3p) and one microRNA from tissue samples (hsa-miR-200c-3p) were validated as significant to distinguish patients with EOC from HIs. KEGG pathway enrichment analysis showed seven significant pathways, which included 'prion diseases', 'proteoglycans in cancer', 'oxytocin signaling pathway', 'hippo signaling pathway', 'adrenergic signaling in cardiomyocytes', 'oocyte meiosis' and 'thyroid hormone signaling pathway', in which the validated miRNAs served a role. This supports the hypothesis that four validated miRNAs, have the potential to be a biomarker of EOC diagnosis and target for treatment.

A Cross-Species Analysis Reveals Dysthyroidism of the Ovaries as a Common Trait of Premature Ovarian Aging

Although the imbalance of circulating levels of Thyroid Hormones (THs) affects female fertility in vertebrates, its involvement in the promotion of Premature Ovarian Aging (POA) is debated. Therefore, altered synthesis of THs in both thyroid and ovary can be a trait of POA. We investigated the relationship between abnormal TH signaling, dysthyroidism, and POA in evolutionary distant vertebrates: from zebrafish to humans. Ovarian T3 signaling/metabolism was evaluated by measuring T3 levels, T3 responsive transcript, and protein levels along with transcripts governing T3 availability (deiodinases) and signaling (TH receptors) in distinct models of POA depending on genetic background and environmental exposures (e.g., diets, pesticides). Expression levels of well-known (Amh, Gdf9, and Inhibins) and novel (miR143/145 and Gas5) biomarkers of POA were assessed. Ovarian dysthyroidism was slightly influenced by genetics since very few differences were found between C57BL/6J and FVB/NJ females. However, diets exacerbated it in a strain-dependent manner. Similar findings were observed in zebrafish and mouse models of POA induced by developmental and long-life exposure to low-dose chlorpyrifos (CPF). Lastly, the T3 decrease in follicular fluids from women affected by diminished ovarian reserve, as well as of the transcripts modulating T3 signaling/availability in the cumulus cells, confirmed ovarian dysthyroidism as a common and evolutionary conserved trait of POA.

Subcellular Distribution of Thyroid Hormone Receptor Beta in Ovarian Cancer

Background: Since the most well-known function of thyroid hormone receptors (TRs) relies on their ability to act as ligand-activated transcription factors, their subcellular localization has been recognized to be relevant for their biological meaning. The current study aimed to determine the prevalence and subcellular distribution of TR beta and TR beta-1 in ovarian cancer (OC). Methods: Tissue was collected from 153 patients that had undergone surgery due to OC at the Department of Obstetrics and Gynaecology of the Ludwig-Maximilians-University Munich. Immunohistochemistry detecting TR beta and TR beta-1 was performed. Staining signals were quantified and tested for association with clinico-pathological parameters including overall survival (OS). Results: The subcellular distribution of TR beta and TR beta-1 differed among histologic subtypes, grade and FIGO stage. TR beta positivity was strongly linked to shortened overall survival (p < 0.001). Strikingly, this shortened OS was mainly attributed to those cases showing complete (p = 0.005) or incomplete shift of TR beta to the cytoplasm (p < 0.001). Significance was lost in multivariate testing. Conclusions: Cytoplasmatic localization of TR beta was associated with reduced OS, at least in univariate analysis. Since TRs have long been supposed to mainly function via the regulation of gene transcription in the nucleus, cytoplasmatic shifting might be interpreted as a regulator of their activity.

Prognostic value of hypothyroidism in patients undergoing intensity-modulated radiation therapy for nasopharyngeal carcinoma

BACKGROUND

The purpose of this study was to investigate the effect of hypothyroidism and thyroxine replacement therapy on the prognosis of nasopharyngeal carcinoma (NPC) patients.

METHODS

The clinical data of 284 NPC patients, who received intensity-modulated radiation therapy (IMRT) between January 2011 and December 2016, were retrospectively analyzed.

RESULTS

Hypothyroidism occurred in 38% of patients. Patients with hypothyroidism had significantly better disease-free survival (DFS) (p = 0.002) and relapse-free survival (RFS) (p = 0.008). Multivariate analysis showed that hypothyroidism was a positive independent prognostic factor (DFS and RFS). Among the patients with hypothyroidism, thyroxine replacement therapy did not yield inferior survival (DFS, RFS, all p > 0.05).

CONCLUSIONS

The NPC patients with complete response are at risk of hypothyroidism, which is attributable to escalating dose. These patients experienced clinical hypothyroidism could be adequately treated with thyroid hormone replacement. Further investigation of the underlying biological mechanism and potential therapeutic implications are required.

Photoperiodic modulation of ovarian metabolic, survival, proliferation and gap junction markers in adult golden hamster, Mesocricetus auratus

Female reproductive physiology is greatly dependent on tight regulation of metabolic and survival factors. Photoperiod regulates female reproductive rhythms but very less information exists explaining whether photoperiod could modulate thyroid hormone homeostasis, metabolic/energy parameters along with survival, proliferation and gap junction proteins in the ovary of a long-day breeder, Mesocricetus auratus. Adult female hamsters were exposed to different photoperiodic regimes i.e., critical photoperiod (CP; 12.5L:11.5D), short photoperiod (SP; 8L:16D) and long photoperiod (LP; 16L:8D) for 12 weeks. LP upregulated thyroidal and gonadal activity as apparent by histoarchitecture, thyroid hormone profile [triiodothyronine (T3), thyroxin (T4) and thyroid stimulating hormone (TSH)], luteinizing hormone (LH), follicle stimulating hormone (FSH), estradiol (E2) and progesterone (P4) levels when compared with SP exposed hamsters. Further, LP increased thyroid hormone receptor-α/deiodinase-2 (TRα/Dio-2), estrogen receptor-α (ERα)/aromatase and insulin receptor/glucose transporter-4 (IR/GLUT-4) expressions in ovary. Interestingly, ovarian sirtuin-1 (SIRT-1) expression was also upregulated under LP condition along with cell proliferation (proliferating cell nuclear antigen or PCNA), survival (B cell lymphoma-2 or Bcl-2) and gap junction (connexin-43) markers when compared to SP exposed hamsters. We also noted elevated levels of circulatory leptin, insulin along with melatonin and its receptor (MT-1) in ovary under SP condition. Thus, we suggest that photoperiod plays a vital role in regulation of thyroid and reproductive hormone homeostasis along with key metabolic and survival markers in the ovary of adult golden hamsters, M. auratus providing further insight into the regulation of female reproductive seasonality in a long-day breeder.

Deep Pathway Analysis V2.0: A Pathway Analysis Framework Incorporating Multi-Dimensional Omics Data

Pathway analysis is essential in cancer research particularly when scientists attempt to derive interpretation from genome-wide high-throughput experimental data. If pathway information is organized into a network topology, its use in interpreting omics data can become very powerful. In this paper, we propose a topology-based pathway analysis method, called DPA V2.0, which can combine multiple heterogeneous omics data types in its analysis. In this method, each pathway route is encoded as a Bayesian network which is initialized with a sequence of conditional probabilities specifically designed to encode directionality of regulatory relationships defined in the pathway. Unlike other topology-based pathway tools, DPA is capable of identifying pathway routes as representatives of perturbed regulatory signals. We demonstrate the effectiveness of our model by applying it to two well-established TCGA data sets, namely, breast cancer study (BRCA) and ovarian cancer study (OV). The analysis combines mRNA-seq, mutation, copy number variation, and phosphorylation data publicly available for both TCGA data sets. We performed survival analysis and patient subtype analysis and the analysis outcomes revealed the anticipated strengths of our model. We hope that the availability of our model encourages wet lab scientists to generate extra data sets to reap the benefits of using multiple data types in pathway analysis. The majority of pathways distinguished can be confirmed by biological literature. Moreover, the proportion of correctly indentified pathways is 10 percent higher than previous work where only mRNA-seq and mutation data is incorporated for breast cancer patients. Consequently, such an in-depth pathway analysis incorporating more diverse data can give rise to the accuracy of perturbed pathway detection.

Follicular GH and IGF1 Levels Are Associated With Oocyte Cohort Quality: A Pilot Study

INTRODUCTION

Oocyte quality contributes to the development of an optimal embryo and thus a successful pregnancy. The objective of this study was to analyse the association between oocyte cohort quality and the follicular levels of growth hormone (GH), insulin-like growth factor 1 (IGF1), 25-hydroxy vitamin D (25OHD), thyroid-stimulating hormone (TSH), free triiodothyronine (fT3), free thyroxine (fT4) and antithyroid antibodies, as a function of intracytoplasmic sperm injection (ICSI) outcomes.

MATERIAL AND METHODS

We conducted a prospective comparative pilot study from January 2013 to December 2017. 59 ICSI cycles constituted an abnormal oocyte cohort (n=34 cycles, in which more than 50% of oocytes presented at least one morphological abnormality) and a normal oocyte cohort (n=25 cycles, in which 50% or less of the oocytes presented at least one morphological abnormality). GH, IGF1, 25OHD, TSH, fT3, fT4 and antithyroid antibodies were measured in follicular fluid.

RESULTS

The fertilisation rate was lower in the abnormal oocyte cohort (65.5% vs. 80%, respectively, p=0.012). Oocytes' proportion with at least one abnormality was 79.4% in the abnormal oocyte cohort and 29.0% in the normal oocyte cohort. The mean number of morphological abnormalities per oocyte was significantly higher in the abnormal oocyte cohort. The follicular levels of GH (4.98 vs. 2.75 mIU/L, respectively; p <0.01) and IGF1 (72.1 vs. 54.2 ng/mL, respectively; p=0.05) were higher in the normal oocyte cohort. There was no association with follicular levels of TSH, fT3, fT4, antithyroid antibodies, or 25OHD.

CONCLUSION

Oocyte cohort quality appears to be associated with follicular levels of GH and IGF1.

Testing different forms of regulation of yolk thyroid hormone transfer in pied flycatchers

Hormones transferred from mothers to their offspring are considered a maternal tool to prepare progeny for expected environmental conditions, increasing maternal and offspring fitness. To flexibly influence offspring, mothers should be able to transmit the hormonal signals independent of their own hormonal status. However, the ability to regulate hormone transfer to the next generation is under debate. We studied the transfer of thyroid hormones (THs) to eggs in a bird model. We elevated thyroxine (T4, the prohormone for the biologically active triiodothyronine, T3) during egg laying using T4 implants in females of a wild population of pied flycatchers (Ficedula hypoleuca), and measured the resulting plasma and yolk T4 and T3 levels. We found an increase in plasma and yolk T4 and no change in plasma or yolk T3 concentration, leading to a decrease in yolk T3/T4 ratio in response to the T4 treatment. The yolk T3/T4 ratio was similar to the plasma ratio in females during the yolking phase. This suggests that mothers are not able to regulate TH transfer to yolk but may regulate the T4 to T3 conversion to avoid potential costs of elevated exposure to the active hormone to herself and to her progeny. The absence of regulation in hormone transfer to eggs is in contrast to our predictions. Future studies on deiodinase activity that converts T4 to T3 in maternal and embryonic tissues may help our understanding of how mothers regulate circulating THs during breeding, as well as the embryos' role in converting maternal T4 to its biologically active T3 form during development.

Cytoplasmic versus nuclear THR alpha expression determines survival of ovarian cancer patients

Purpose

Thyroid hormone receptors (THR) have manifold functions and are involved in the carcinogenesis of several tumor types. Within this study, we aimed to investigate the expression pattern (nuclear versus cytoplasmic) of the THR alpha and its impact on patients survival in ovarian cancer (OvCa).

Methods

The presence of the thyroid hormone receptors THRα, THRα1 and − 2 was investigated in 156 ovarian cancer samples using immunohistochemistry (IHC) using semi-quantitative immunoreactivity (IR) scores and correlated with clinical, pathological data, subtype of ovarian cancer, clinical data, staining of 20 already described OvCa marker proteins and overall survival (OS).

Results

Among all subtypes of OvCa, clear cell carcinomas showed the highest THRα expression. Furthermore, nuclear THRα was associated with a reduced survival in this subtype. However, nuclear expressed THRα1 turned out to be a positive prognosticator for all subtypes of OvCa patients. Nuclear THRα2 is a positive prognosticator for OvCa patients of the serous subtype. In contrast, cytoplasmic expression THRα2 was associated with a reduced OS in all subtypes of OvCa patients; while, cytoplasmic expression of THRα1 is associated with reduced OS in mucinous OvCa patients only. In addition, THRα expression correlates with gonadotropin receptors, steroid hormone receptors, TA-MUC1 and glycodelin.

Conclusion

Depending on nuclear or cytoplasmic expression, our study shows that THRα and its isoforms 1 and 2 provide different prognostic information for ovarian cancer patients. Further investigations should analyze if THRs may represent new endocrine targets for the treatment of ovarian cancer.

Electronic supplementary material

The online version of this article (10.1007/s00432-020-03241-7) contains supplementary material, which is available to authorized users.

Thyroid Hormones and Functional Ovarian Reserve: Systemic vs. Peripheral Dysfunctions

Thyroid hormones (THs) exert pleiotropic effects in different mammalian organs, including gonads. Genetic and non-genetic factors, such as ageing and environmental stressors (e.g., low-iodine intake, exposure to endocrine disruptors, etc.), can alter T4/T3 synthesis by the thyroid. In any case, peripheral T3, controlled by tissue-specific enzymes (deiodinases), receptors and transporters, ensures organ homeostasis. Conflicting reports suggest that both hypothyroidism and hyperthyroidism, assessed by mean of circulating T4, T3 and Thyroid-Stimulating Hormone (TSH), could affect the functionality of the ovarian reserve determining infertility. The relationship between ovarian T3 level and functional ovarian reserve (FOR) is poorly understood despite that the modifications of local T3 metabolism and signalling have been associated with dysfunctions of several organs. Here, we will summarize the current knowledge on the role of TH signalling and its crosstalk with other pathways in controlling the physiological and premature ovarian ageing and, finally, in preserving FOR. We will consider separately the reports describing the effects of circulating and local THs on the ovarian health to elucidate their role in ovarian dysfunctions.

Pure T3 thyrotoxicosis from a Struma Ovarii characterised by a paradoxical rise in thyroxine on treatment

SUMMARY

A 33-year-old female presented with a right 11.6 cm ovarian cyst. Routine pre-operative thyroid function tests showed thyroid stimulating hormone (TSH) of less than 0.02 mU/L (0.3-3.05) and a free thyroxine (FT4) of 5.5 pmol/L (10-28.2) suggesting either assay interference, triiodothyronine (T3) ingestion or hypopituitary hypothyroidism. A free triiodothyronine (FT3) level was requested which was high normal 6.9 pmol/L (3.1-8.1). Parallel assays on a different platform were similar but with a raised FT3 of 7.2 pmol/L (3.1-6.8). TSH receptor stimulating antibody (TSHAb) and thyroid peroxidase antibodies (TPO) were negative. Antithyroglobulin antibody (TgAb) was positive at 155.6 IU/mL (0-115). She was clinically euthyroid. Thyroid ultrasound showed a normal sized mildly heterogeneous gland with low blood flow and a solitary 1.5 cm U3 (BTA) nodule with higher blood flow. Thyroid Tc99m uptake was very low 0.2% (0.6-3.0) with no nodule uptake. These results demonstrated an extrathyroidal source of excessive autonomous T3 production resulting in the low thyroxine (T4). With carbimazole her TSH rose to 11.9 mU/L, FT4 rose to 7.7 pmol/L and FT3 reduced to 3.6 pmol/L. Histological diagnosis was Struma Ovarii. Her TSH, FT4 and FT3 remained normal thereafter. In conclusion, an extrathyroidal source of high T3 secretion was diagnosed using routine thyroid tests and scans. We believe this is the first description of a Struma Ovarii exclusively secreting T3 hormone characterised by the paradoxical rise of a low FT4 to normal with treatment. Two years later she developed non-secreting peritoneal deposits of highly differentiated follicular carcinoma.

LEARNING POINTS

Abnormally low TSH and FT4 levels suggestive of possible T3 ingestion, or less likely, hypopituitary hypothyroidism should always be followed by an assay of FT3. The diagnosis of an extrathyroidal source of T3 can be made using conventional thyroid tests, thyroid ultrasound scanning and technetium thyroid uptake and scan imaging. In a pre-menopausal patient this avoids a radiation dose to the pelvis. Pelvic radioisotope scanning of a suspected Struma Ovarii causing thyrotoxicosis can be reserved for patients whose thyroid function remains abnormal after initial surgery. Carbimazole is effective in the treatment of extrathyroidal autonomous T3 hormone production from a Struma Ovarii. The pathological appearance of a Struma Ovarii is not a guide to its malignancy. Even with a benign appearance they can disseminate to peritoneum, as highly differentiated follicular carcinoma (previously known as peritoneal strumosis). Hyperthyroid secretion by a Struma Ovarii may not be replicated in the metastatic follicular carcinoma in the peritoneum.

Thyroid hormones act as mitogenic and pro survival factors in rat ovarian follicles

PURPOSE

Thyroid disorders are clinically associated with impaired fertility in women, and these abnormalities can be improved by restoring the euthyroid state. The exact mechanisms of thyroid effect on female fertility are not well known; however, it is conceivable that thyroid hormones (THs) might act on ovarian physiology via receptors in granulosa cells. This work is aimed at evaluating the effects of THs on non-tumoral granulosa cells and follicles.

METHODS

Freshly isolated rat ovarian follicles and granulosa cells were exposed to T3 or T4 (THs). Cell growth and viability were evaluated by cell counting and the MTT assay, respectively, follicle growth was evaluated by volume measurements. Apoptosis was evaluated by the TUNEL assay and active Caspase 3 staining. rGROV cells were exposed to T3, and apoptosis was induced by serum deprivation. Bcl2, Bcl-2-associated X protein (BAX), Akt and pAkt expression were evaluated by western blot.

RESULTS

T3 induced a 40% increase in follicle volume (after 7 days). This increase was presumably due to the observed decrease (33%) in the apoptotic rate of the granulosa cell population. Both T3 and T4 caused a dose-dependent increase in rat granulosa cell number and viability. In addition, THs decreased the cell apoptotic rate in a dose-dependent manner. In both conditions, T3 appeared to be more efficient. In rGROV cells, 100 nM T3 induced cell growth and, in the absence of growth factors, reduced cell apoptosis by 40%, downregulating Caspase 3 and BAX. This effect was associated with an increase in pAkt levels. The involvement of the PI3 K pathway was confirmed by the ability of the PI3 K specific inhibitor (LY-294,002) to abolish T3 pro-survival action.

CONCLUSIONS

THs influence cell survival of ovarian granulosa cells. This effect likely contributes to the TH-induced follicle volume increase.

Combined administration of docosahexaenoic acid and thyroid hormone synergistically enhances rat liver levels of resolvins RvD1 and RvD2

Supplementation with omega-3 fatty acids or thyroid hormone (T₃) exhibit negative effects on inflammatory reactions in experimental animals. The aim of this work was to assess the hypothesis that docosahexaenoic acid (DHA) plus T₃ co-administration enhances liver resolvin (Rv) levels as inflammation resolution mediators. Combined DHA (daily doses of 300 mg/kg for 3 consecutive days)-T₃ (0.05 mg/kg at the fourth day) administration significantly increased the content of hepatic RvD1 and RvD2, without changes in that of RvE1 and RvE2, an effect that exhibits synergy when compared to the separate DHA and T₃ treatments. Under these conditions, liver DHA levels increased by DHA administration were diminished when combined with T₃ (p < 0.05), suggesting enhancement in resolvin D biosynthesis in extrahepatic tissues. It is concluded that co-administration of DHA and T₃ rises the capacity of the liver for inflammation resolution by augmenting RvD1(2) availability, which represents an important protocol in hepatoprotection in the clinical setting.

Association of Thyroid Function and Autoimmunity with Ovarian Reserve in Women Seeking Infertility Care

BACKGROUND

While overt thyroid disease is a well known risk factor for infertility, the potential consequences of mild thyroid dysfunction or thyroid autoimmunity remain unknown. Experimental studies suggest a considerable role for thyroid hormone in the physiological mechanisms of ovarian reserve, but translation of such findings to human studies remains rare. A potential role for thyroid function in female reproduction could be especially relevant when the cause of infertility remains unknown, such as in women with diminished ovarian reserve (DOR) or unexplained infertility. The aims of this study were to investigate the association of thyroid function and autoimmunity with markers of ovarian reserve day 3 follicle-stimulating hormone (FSH) concentrations and antral follicle count (AFC), and to investigate whether thyroid function or autoimmunity may have different effects in women with DOR or unexplained infertility.

METHODS

Thyrotropin, free thyroxine, thyroxine, free triiodothyronine (fT3), triiodothyronine, thyroid peroxidase antibodies (TPOAbs), and thyroglobulin antibodies (TgAbs), as well as AFC and the day 3 FSH concentration, were measured among women seeking fertility treatment at the Massachusetts General Hospital Fertility Center. Multiple linear or mixed regression models were used to study the association of thyroid function or autoimmunity with AFC or day 3 FSH.

RESULTS

In the total study population (436 women, 530 AFC measurements), there was no association of thyroid function or TPOAb positivity with AFC. However, TgAb positivity was associated with a higher AFC (mean difference = 3.4 [95% confidence interval (CI) 1.8-5.1], p < 0.001). In women with DOR or unexplained infertility, lower fT3 and TPOAb positivity were associated with a lower AFC (fT3: continuous nonlinear association, p = 0.009; TPOAb positivity: -2.3 follicles [confidence interval -3.8 to -0.5], p = 0.01), while TgAb positivity was not associated with AFC. Neither thyroid function nor thyroid antibody positivity was associated with the day 3 FSH concentration.

CONCLUSIONS

This study found that lower fT3 and TPOAb positivity are associated with a lower AFC in women with DOR or unexplained infertility. Future studies are required to replicate these findings and further elucidate the role of TgAbs and underlying mechanisms through which thyroid function and autoimmunity is associated with ovarian reserve.

Crosstalk between integrin αvβ3 and ERα contributes to thyroid hormone-induced proliferation of ovarian cancer cells

Ovarian cancer is the leading cause of death in gynecological diseases. Thyroid hormone promotes proliferation of ovarian cancer cells via cell surface receptor integrin αvβ3 that activates extracellular regulated kinase (ERK1/2). However, the mechanisms are still not fully understood. Thyroxine (T₄) at a physiologic total hormone concentration (10⁻⁷ M) significantly increased proliferating cell nuclear antigen (PCNA) abundance in these cell lines, as did 3, 5, 3′-triiodo-L-thyronine (T₃) at a supraphysiologic concentration. Thyroid hormone (T₄ and T₃) treatment of human ovarian cancer cells resulted in enhanced activation of the Ras/MAPK(ERK1/2) signal transduction pathway. An MEK inhibitor (PD98059) blocked hormone-induced cell proliferation but not ER phosphorylation. Knock-down of either integrin αv or β3 by RNAi blocked thyroid hormone-induced phosphorylation of ERK1/2. We also found that thyroid hormone causes elevated phosphorylation and nuclear enrichment of estrogen receptor α (ERα). Confocal microscopy indicated that both T4 and estradiol (E₂) caused nuclear translocation of integrin αv and phosphorylation of ERα. The specific ERα antagonist (ICI 182,780; fulvestrant) blocked T₄-induced ERK1/2 activation, ERα phosphorylation, PCNA expression and proliferation. The nuclear co-localization of integrin αv and phosphorylated ERα was inhibited by ICI. ICI time-course studies indicated that mechanisms involved in T₄- and E₂-induced nuclear co-localization of phosphorylated ERα and integrin αv are dissimilar. Chromatin immunoprecipitation results showed that T₄-induced binding of integrin αv monomer to ERα promoter and this was reduced by ICI. In summary, thyroid hormone stimulates proliferation of ovarian cancer cells via crosstalk between integrin αv and ERα, mimicking functions of E₂.

The Interplay Between Epithelial-Mesenchymal Transition (EMT) and the Thyroid Hormones-αvβ3 Axis in Ovarian Cancer

Ovarian cancer is a highly metastatic disease. The metastatic potential is enhanced by epithelial to mesenchymal transition (EMT) in which αvβ3 integrin plays a role. Thyroid hormones (L-thyroxine, T4, and 3,5,3'-triiodo-L-thyronine, T3) bind this integrin, and we hypothesized that the thyroid hormone-αvβ3 axis may be involved in EMT activity in ovarian cancer. The transcription (mRNA), protein abundance (westerns), and protein localization (fluorescence microscopy) of several EMT markers were studied in ovarian cancer cells (OVCAR-3, A2780, and SKOV-3) treated with 1 nM T3 or 100 nM T4 for 1-24 h. The protein levels of β-catenin, and its downstream targets, zeb-1, slug, and vimentin, were significantly induced by both hormones, while the effect on transcription was limited. The pre-incubation of the cells overnight with two integrin inhibitors, RGD (0.1-10 μM) or αvβ3 blocking antibody (1-100 ng/mL), prevented the induction of β-catenin by T3 and zeb-1 by T4, indicating direct integrin involvement. The transcription of the mesenchymal markers, β-catenin, zeb-1, slug/snail, vimentin, and n-cadherin was hardly affected by T3 and T4, while that of the epithelial markers, e-cadherin and zo-1, was inhibited. Our results suggest a novel role for the thyroid hormone-αvβ3 axis in EMT, with possible implications for ovarian cancer metastasis.

The role of thyrostimulin and its potential clinical significance

Thyrostimulin is a glycoprotein heterodimer of GPA2 and GPB5, first described in 2002. It is involved in the physiological function of several tissues. Moreover, evidence points towards the ability of thyrostimulin's individual monomers to induce a biological effect, which could denote the circulatory/systemic effects of the molecule when found in higher concentrations. From the evolutionary point of view, thyrostimulin shares a binding epitope with the thyroid-stimulating hormone for the thyroid stimulating hormone receptor, whilst possessing affinity for another unique binding site on the same receptor. Although thyrostimulin can be involved in the hypothalamicpituitary- thyroid axis, its presence in various tissues in an eclectic array of different species renders it multifunctional. From weight loss via increasing metabolic rate to progression of cancer in human ovaries, it is certainly not a signaling molecule to overlook. Furthermore, thyrostimulin has been implicated in bone metabolism, acute illness, and reproductive function. In summary, to our knowledge, this is the first review dealing with the physiological role of thyrostimulin and its potential applications in the clinical practice.

History of thyroid disease and survival of ovarian cancer patients: results from the Ovarian Cancer Association Consortium, a brief report

BACKGROUND

Findings from in vitro studies suggest that increased exposure to thyroid hormones can influence progression of ovarian tumours. However, epidemiologic evidence on this topic is limited.

METHODS

We pooled data from 11 studies from the Ovarian Cancer Association Consortium. Using multivariate Cox proportional hazards models, we estimated associations between hyper- and hypothyroidism and medications prescribed for these conditions with 5-year all-cause survival among women diagnosed with invasive ovarian cancer.

RESULTS

Overall, there was a nonsignificant association with history of hyperthyroidism (n=160 cases) and mortality (HR=1.22; 95% CI=0.97-1.53). Furthermore, diagnosis of hyperthyroidism within the 5 years before ovarian cancer diagnosis was associated with an increased risk of death (HR=1.94; 95% CI=1.19-3.18). A more modest association was observed with history of hypothyroidism (n=624 cases) and mortality (HR=1.16; 95% CI=1.03-1.31). Neither duration of hypothyroidism nor use of thyroid medications was associated with survival.

CONCLUSIONS

In this large study of women with ovarian cancer, we found that recent history of hyperthyroidism and overall history of hypothyroidism were associated with worse 5-year survival.

Thyroid peroxidase identified in human granulosa cells: another piece to the thyroid-ovary puzzle?

Thyroid hormones seemingly influence the maturation of the human oocyte. Thyroid hormone receptors have been isolated in granulosa mural and cumulus cells and the mature oocyte of the human ovarian follicle. Thyroid hormones are present in follicular fluid in concentrations similar to those in serum. Most importantly, enzymes involved in the chain that regulate the generation of thyroid hormones have been found in granulosa cells. For the first time, we have isolated thyroid peroxidase by immunocytochemistry in the granulosa cumulus cells of the human ovarian follicle, thereby supporting the hypothesis that the human ovarian follicle may be an independent thyroid-hormone producing unit.

Distribution of thyroid hormone and thyrotropin receptors in reproductive tissues of adult female rabbits

PURPOSE

Thyroid dysfunctions are related to anovulation, miscarriages, and infertility in women and laboratory animals. Mechanisms associated with these effects are unknown, although indirect or direct actions of thyroid hormones and thyrotropin could be assumed. The present study aimed to identify the distribution of thyroid hormones (TRs) and thyrotropin (TSHR) receptors in reproductive organs of female rabbits.

MATERIAL AND METHODS

Ovary of virgin and pregnant rabbits, as well as the oviduct, uterus, and vagina of virgin rabbits were excised, histologically processed, and cut. Slices from these organs were used for immunohistochemical studies for TRα1-2, TRß1, and TSHR.

RESULTS

The presence of TRs and TSHR was found in the primordial, primary, secondary, tertiary, and Graafian follicles of virgin rabbits, as well as in the corpora lutea, corpora albicans, and wall of hemorrhagic cysts of pregnant rabbits. Oviductal regions (fimbria-infundibulum, ampulla, isthmus, and utero-tubal junction), uterus (endometrium and myometrium), and vagina (abdominal, pelvic, and perineal portions) of virgin rabbits showed anti-TRs and anti-TSHR immunoreactivity. Additionally, the distal urethra, paravaginal ganglia, levator ani and iliococcygeus muscles, dorsal nerve and body of the clitoris, perigenital skin, and prostate had TRs and TSHR.

CONCLUSIONS

The wide presence of TRs and TSHR in female reproductive organs suggests varied effects of thyroid hormones and thyrotropin in reproduction.

Zebrafish: A Versatile Animal Model for Fertility Research

The utilization of zebrafish in biomedical research is very common in the research world nowadays. Today, it has emerged as a favored vertebrate organism for the research in science of reproduction. There is a significant growth in amount numbers of scientific literature pertaining to research discoveries in reproductive sciences in zebrafish. It has implied the importance of zebrafish in this particular field of research. In essence, the current available literature has covered from the very specific brain region or neurons of zebrafish, which are responsible for reproductive regulation, until the gonadal level of the animal. The discoveries and findings have proven that this small animal is sharing a very close/similar reproductive system with mammals. More interestingly, the behavioral characteristics and along with the establishment of animal courtship behavior categorization in zebrafish have laid an even stronger foundation and firmer reason on the suitability of zebrafish utilization in research of reproductive sciences. In view of the immense importance of this small animal for the development of reproductive sciences, this review aimed at compiling and describing the proximate close similarity of reproductive regulation on zebrafish and human along with factors contributing to the infertility, showing its versatility and its potential usage for fertility research.

Thyroid Hormone Receptors Are Differentially Expressed in Granulosa and Cervical Cells of Infertile Women

BACKGROUND

Thyroid hormones are known to exert an important role in reproduction. The objective of this study was to evaluate the expression of thyroid hormone receptors (TR) in granulosa (GC) and cervical cells (CC) of infertile euthyroid women.

METHODS

In a cross-sectional study, 31 consecutive infertile and 18 fertile women undergoing oocyte retrieval procedures were investigated. The expression of TRα1, TRα2, and TRβ was evaluated in GCs and uterine CC from infertile and fertile euthyroid women. β2 adrenergic receptor (ADRβ2) mRNA levels and the expression of genes linked to fertility such as gremlin-1 (GREM1), hyaluronan synthase 2 (HAS2), and prostaglandin-endoperoxide synthase 2 (PTGS2) were also evaluated.

RESULTS

In GCs, the expression of the thyroid hormone receptor TRα2, which exerts a dominant negative effect, increased with age in all women tested. TRα2 mRNA was increased in infertile versus fertile women, in parallel to decreased ADRβ2 mRNA. As expected, the expression of genes associated with fertility (i.e., GREM1 and PTGS2) was downregulated in infertile women, in parallel to decreased ADRβ2 mRNA and increased TRα2 mRNA. In uterine CCs, a positive association of ADRβ2 mRNA with TRα1:TRα2 ratio was observed. Importantly, GCs from infertile women whose oocytes did not result in pregnancy had increased expression of TRα2 (p = 0.017) and lower ADRβ2 (p = 0.008), GREM1 (p = 0.003), and PTGS2 (p = 0.002) mRNAs than fertile women whose oocytes resulted in pregnancy. Infertile women also showed more TRα2 (p = 0.033) mRNA in CCs than fertile women whose oocytes resulted in pregnancy.

CONCLUSIONS

The expression of different markers of intracellular thyroid function is linked to fertility status.

Donor TSH level is associated with clinical pregnancy among oocyte donation cycles

PURPOSE

The purpose of the study is to evaluate the association between donor TSH level (independent of recipient TSH level) and recipient pregnancy outcome among fresh donor oocyte IVF cycles.

METHODS

This is a retrospective cohort study investigating 232 consecutive fresh donor-recipient cycles (200 total oocyte donors) at an academic medical center. Main outcome measures include clinical pregnancy and live birth.

RESULTS

Cycles were categorized into two groups based on donor TSH level (< 2.5 and ≥ 2.5 mIU/L). After controlling for multiple donor and recipient characteristics, the probability of clinical pregnancy was significantly lower among donors with TSH levels ≥2.5 mIU/L compared to those with TSH values <2.5 mIU/L (43.1 %, 95 % CI 28.5-58.9, versus 66.7 %, 95 % CI 58.6-73.9, respectively, p = 0.01). The difference in live birth rates between the two groups did not achieve statistical significance (43.1 %, 95 % CI 28.8-58.6, versus 58.0 %, 95 % CI 50.0-65.6, respectively, p = 0.09).

CONCLUSIONS

Donor TSH level, independent of recipient TSH level, is associated with recipient clinical pregnancy. These findings suggest that thyroid function may impact the likelihood of pregnancy at the level of the oocyte.

Thyroid hormone regulates adhesion, migration and matrix metalloproteinase 9 activity via αvβ3 integrin in myeloma cells

Thyroid hormone (3,5,3′-triiodothyronine, T3; L-thyroxine, T4) enhances cancer cell proliferation, invasion and angiogenesis via a discrete receptor located near the RGD recognition site on αvβ3 integrin. Tetraiodothyroacetic acid (tetrac) and its nanoparticulate formulation interfere with binding of T3/T4 to the integrin. This integrin is overexpressed in multiple myeloma (MM) and other cancers. MM cells interact with αvβ3 integrin to support growth and invasion. Matrix metalloproteinases (MMPs) are a family of enzymes active in tissue remodeling and cancer. The association between integrins and MMPs secretion and action is well established. In the current study, we examined the effects of thyroid hormone on myeloma cell adhesion, migration and MMP activity.

We show that T3 and T4 increased myeloma adhesion to fibronectin and induced αvβ3 clustering. In addition, the hormones induced MMP-9 expression and activation via αvβ3 and MAPK induction. Bortezomib, a standard myeloma treatment, caused a decrease in activity/quantity of MMPs and thyroid hormone opposed this effect. RGD peptide and tetrac impaired the production of MMP-9 in cell lines and in primary BM cells from myeloma patients.

In conclusion, thyroid hormone-dependent regulation via αvβ3 of myeloma cell adhesion and MMP-9 production may play a role in myeloma migration and progression.

The thyroid hormone-αvβ3 integrin axis in ovarian cancer: regulation of gene transcription and MAPK-dependent proliferation

Ovarian carcinoma is the fifth common cause of cancer death in women, despite advanced therapeutic approaches. αvβ3 integrin, a plasma membrane receptor, binds thyroid hormones (L-thyroxine, T4; 3,5,3'-triiodo-L-thyronine, T3) and is overexpressed in ovarian cancer. We have demonstrated selective binding of fluorescently labeled hormones to αvβ3-positive ovarian cancer cells but not to integrin-negative cells. Physiologically relevant T3 (1 nM) and T4 (100 nM) concentrations in OVCAR-3 (high αvβ3) and A2780 (low αvβ3) cells promoted αv and β3 transcription in association with basal integrin levels. This transcription was effectively blocked by RGD (Arg-Gly-Asp) peptide and neutralizing αvβ3 antibodies, excluding T3-induced β3 messenger RNA, suggesting subspecialization of T3 and T4 binding to the integrin receptor pocket. We have provided support for extracellular regulated kinase (ERK)-mediated transcriptional regulation of the αv monomer by T3 and of β3 monomer by both hormones and documented a rapid (30-120 min) and dose-dependent (0.1-1000 nM) ERK activation. OVCAR-3 cells and αvβ3-deficient HEK293 cells treated with αvβ3 blockers confirmed the requirement for an intact thyroid hormone-integrin interaction in ERK activation. In addition, novel data indicated that T4, but not T3, controls integrin's outside-in signaling by phosphorylating tyrosine 759 in the β3 subunit. Both hormones induced cell proliferation (cell counts), survival (Annexin-PI), viability (WST-1) and significantly reduced the expression of genes that inhibit cell cycle (p21, p16), promote mitochondrial apoptosis (Nix, PUMA) and tumor suppression (GDF-15, IGFBP-6), particularly in cells with high integrin expression. At last, we have confirmed that hypothyroid environment attenuated ovarian cancer growth using a novel experimental platform that exploited paired euthyroid and severe hypothyroid serum samples from human subjects. To conclude, our data define a critical role for thyroid hormones as potent αvβ3-ligands, driving ovarian cancer cell proliferation and suggest that disruption of this axis may present a novel treatment strategy in this aggressive disease.

Differential transcriptional and protein expression of thyroid-stimulating hormone receptor in ovarian carcinomas

OBJECTIVE

Thyroid-stimulating hormone (TSH) regulates normal thyroid function by binding to its receptor (thyroid-stimulating hormone receptor -TSHR) that is expressed at the surface of thyroid cells. Recently, it has been demonstrated that TSHR is abundantly expressed in several tissues apart from the thyroid, among them the normal ovarian surface epithelium. The role of TSHR expression outside the thyroid is not completely understood. The current study examines possible alterations of TSHR expression in ovarian carcinomas and its implication in ovarian carcinogenesis.

MATERIALS AND METHODS

Quantitative real-time polymerase chain reaction and immunohistochemistry analysis of TSHR expression were performed in 34 ovarian carcinoma specimens and 10 normal ovarian tissues (controls).

RESULTS

Significant reduction in TSHR messenger RNA (mRNA) expression was detected in ovarian carcinomas (mean [SD]: 0.518 [0.0934] vs normal, 49.4985 [89.1626]; P < 0.001, Mann-Whitney U test), whereas TSHR protein levels were significantly increased (percentage of positive cells: cancer, 73.55% [20.09%], vs normal, 54.54% [21.14%]; intensity: cancer, 2.52 [0.508], vs normal 1 [0]; P = 0.012, Mann-Whitney U test). No significant differences in TSHR mRNA were found according to history of thyroid disease.

CONCLUSIONS

Our study describes for the first time alterations in TSHR expression both at mRNA and protein levels in ovarian carcinomas. The discrepancy between the decreased levels of the TSHR mRNA and the increased protein expression has already been described in thyroid carcinomas and might be due to alterations in its degradation by the ubiquitin system or other unknown mechanisms. Further analysis could elucidate the role of these findings in ovarian carcinogenesis.

Comparative Study of Alterations in Tri-iodothyronine (T3) and Thyroxine (T4) Hormone Levels in Breast and Ovarian Cancer

Objective : The present study was designed to investigate variations in the levels of thyroid hormones (T3, T4) in breast and ovarian cancers patients. Methods : A total 120 subjects were recruited (without thyroid history) divided into three groups; A, B and C. Group A as control with healthy individuals. While group B and group C were consisting of breast cancer and ovarian cancer patient respectively. Blood samples (5 ml) were taken and analyzed to estimate the levels of serum T3 (tri-iodothyronine) and T4 (thyroxin) hormones. R esults : Statistically significant difference (P=0.000* and P=0.017*) was obtained among all groups. A significant increase in T3 (P=0.000*) and T4 (0.005*) levels was observed among breast cancer patients as compared to healthy controls. While for ovarian cancer patients conflicting results were found for T3 and T4 levels in the serum i.e. insignificant difference was found in T3 (P=0.209) and T4 (P=0.050) as compared to control. Our results showed that in the breast cancer and ovarian cancer patients the thyroid hormone (T3 and T4) level has been altered from the normal ranges as compared to the normal healthy individuals. Conclusion : We conclude that hyperthyroidism has profound effects on breast cancer and ovarian cancer cells proliferation.

Recurrence of differentiated thyroid carcinoma during full TSH suppression: is the tumor now thyroid hormone dependent?

Well-standardized primary treatment and long-term management of differentiated thyroid carcinoma (DTC) include lowering or suppression of host thyrotropin (TSH) with exogenous L-thyroxine (T₄). This treatment recognizes the trophic action of TSH on DTC cells. Suppression of endogenous TSH with T₄ is continued in recurrent disease. However, T₄ can induce proliferation of follicular and papillary thyroid carcinoma cell lines and of other human carcinoma cells. The proliferative mechanism is initiated at a cell surface receptor for T₄ on integrin αvβ3, a receptor by which the hormone also inhibits p53-dependent apoptosis in tumor cells. In recurrent DTC with satisfactory suppression of endogenous TSH, we discuss here the possibility that the tumor is no longer TSH dependent and that T₄ has become a critical growth factor for the cancer.

Nanotetrac targets integrin αvβ3 on tumor cells to disorder cell defense pathways and block angiogenesis

The extracellular domain of integrin αvβ3 contains a receptor for thyroid hormone and hormone analogs. The integrin is amply expressed by tumor cells and dividing blood vessel cells. The proangiogenic properties of thyroid hormone and the capacity of the hormone to promote cancer cell proliferation are functions regulated nongenomically by the hormone receptor on αvβ3. An L-thyroxine (T4) analog, tetraiodothyroacetic acid (tetrac), blocks binding of T4 and 3,5,3'-triiodo-L-thyronine (T3) by αvβ3 and inhibits angiogenic activity of thyroid hormone. Covalently bound to a 200 nm nanoparticle that limits its activity to the cell exterior, tetrac reformulated as Nanotetrac has additional effects mediated by αvβ3 beyond the inhibition of binding of T4 and T3 to the integrin. These actions of Nanotetrac include disruption of transcription of cell survival pathway genes, promotion of apoptosis by multiple mechanisms, and interruption of repair of double-strand deoxyribonucleic acid breaks caused by irradiation of cells. Among the genes whose expression is suppressed by Nanotetrac are EGFR, VEGFA, multiple cyclins, catenins, and multiple cytokines. Nanotetrac has been effective as a chemotherapeutic agent in preclinical studies of human cancer xenografts. The low concentrations of αvβ3 on the surface of quiescent nonmalignant cells have minimized toxicity of the agent in animal studies.

Molecular basis of thyrotropin and thyroid hormone action during implantation and early development

BACKGROUND

Implantation and early embryo development are finely regulated processes in which several molecules are involved. Evidence that thyroid hormones (TH: T4 and T3) might be part of this machinery is emerging. An increased demand for TH occurs during gestation, and any alteration in maternal thyroid physiology has significant implications for both maternal and fetal health. Not only overt but also subclinical hypothyroidism is associated with infertility as well as with obstetric complications, including disruptions and disorders of pregnancy, labor, delivery, and troubles in early neonatal life.

METHODS

We searched the PubMed and Google Scholar databases for articles related to TH action on ovary, endometrium, trophoblast maturation and embryo implantation. In addition, articles on the regulation of TH activity at cellular level have been reviewed. The findings are hereby summarized and critically discussed.

RESULTS

TH have been shown to influence endometrial, ovarian and placental physiology. TH receptors (TR) and thyrotropin (thyroid-stimulating hormone: TSH) receptors (TSHR) are widely expressed in the feto-maternal unit during implantation, and both the endometrium and the trophoblast might be influenced by TH either directly or through TH effects on the synthesis and activity of implantation-mediating molecules. Interestingly, due to the multiplicity of mechanisms involved in TH action (e.g. differential expression of TR isoforms, heterodimeric receptor partners, interacting cellular proteins, and regulating enzymes), the TH concentration in blood is not always predictive of their cellular availability and activity at both genomic and nongenomic level.

CONCLUSIONS

In addition to the known role of TH on the hormonal milieu of the ovarian follicle cycle, which is essential for a woman's fertility, evidence is emerging on the importance of TH signaling during implantation and early pregnancy. Based on recent observations, a local action of TH on female reproductive organs and the embryo during implantation appears to be crucial for a successful pregnancy. Furthermore, an imbalance in the spatio-temporal expression of factors involved in TH activity might induce early arrest of pregnancy in women considered as euthyroid, based on their hormonal blood concentration. In conclusion, alterations of the highly regulated local activity of TH may play a crucial, previously underestimated, role in early pregnancy and pregnancy loss. Further studies elucidating this topic should be encouraged.

Luteal expression of thyroid hormone receptors during gestation and postpartum in the rat

BACKGROUND

Progesterone (P4) is the main steroid secreted by the corpora lutea (CL) and is required for successful implantation and maintenance of pregnancy. Although adequate circulating levels of thyroid hormone (TH) are needed to support formation and maintenance of CL during pregnancy, TH signaling had not been described in this gland. We determined luteal thyroid hormone receptor isoforms (TR) expression and regulation throughout pregnancy and under the influence of thyroid status, and in vitro effects of triiodothyronine (T3) exposure on luteal P4 synthesis.

METHODS

Euthyroid female Wistar rats were sacrificed by decapitation on gestational day (G) 5, G10, G15, G19, or G21 of pregnancy or on day 2 postpartum (L2). Hyperthyroidism and hypothyroidism were induced in female Wistar rats by daily administration of thyroxine (T4; 0.25 mg/kg subcutaneously) or 6-propyl-2-thiouracil (PTU; 0.1 g/L in drinking water), respectively. Luteal TR expression of mRNA was determined using real-time reverse-transcription quantitative polymerase chain reaction, and of protein using Western blot and immunohistochemistry. Primary cultures of luteal cells and of luteinized granulosa cells were used to study in vitro effects of T3 on P4 synthesis. In addition, the effect of T3 on P4 synthesis under basal conditions and under stimulation with luteinizing hormone (LH), prolactin (PRL), and prostaglandin E2 (PGE2) was evaluated.

RESULTS

TRα1, TRα2, and TRβ1 mRNA were present in CL, increasing during the first half and decreasing during the second half of pregnancy. At the protein level, TRβ1 was abundantly expressed during gestation reaching a peak at G19 and decreasing afterwards. TRα1 was barely expressed during early gestation, peaked at G19, and diminished thereafter. Expression of TRβ1 and TRα1 at the protein and mRNA level were not influenced by thyroid status. T3 neither modified P4 secretion from CL of pregnancy nor its synthesis in luteinized granulosa cells in culture.

CONCLUSIONS

This study confirms for the first time the presence of TR isoforms in the CL during pregnancy and postpartum, identifying this gland as a TH target during gestation. TR expression is modulated in this tissue in accordance with the regulation of P4 metabolism, and the abrupt peripartum changes suggest a role of TH during luteolysis. However, TH actions on the CL do not seem to be related to a direct regulation of P4 synthesis.

The gep proto-oncogene Gα12 mediates LPA-stimulated activation of CREB in ovarian cancer cells

Lysophosphatidic acid (LPA) plays a critical role in the pathophysiology of ovarian cancers. Previous studies have shown that LPA stimulates the proliferation of ovarian cancer cells via Gα12. The present study utilizing Protein/DNA array analyses of LPA-stimulated HeyA8 cells in which the expression of Gα12 was silenced, demonstrates for the first time that Gα12-dependent mitogenic signaling by LPA involves the atypical activation cAMP-response element binding protein (CREB). Results indicate that the robust activation of CREB by LPA is an early event that can be monitored by the phosphorylation of SER133 of CREB as early as 3min. The findings that the expression of the constitutively activated mutant of Gα12 stimulates CREB even in the absence of LPA in multiple ovarian cancer cell lines confirm the direct role of Gα12 in the activation of CREB. This is further substantiated by the observation that the silencing of Gα12 drastically attenuates LPA-stimulated phosphorylation of CREB. Our results also establish that LPA-Gα12-dependent activation of CREB is through a cAMP-independent, but Ras-ERK-dependent mechanism. More significantly, our findings indicate that the expression of the dominant negative S133A mutant of CREB leads to a reduction in LPA-stimulated proliferation of HeyA8 ovarian cancer cells. Thus, results presented here demonstrate for the first time that CREB is a critical signaling node in LPA-LPAR and Gα12/gep proto-oncogene stimulated oncogenic signaling in ovarian cancer cells.

A large cohort study of hypothyroidism and hyperthyroidism in relation to gynecologic cancers

Background. Thyroid status may influence tumorigenesis of gynecologic cancers, yet epidemiologic studies of this relationship are limited and inconsistent. Methods. We evaluated the association of self-reported history of physician-diagnosed hypothyroidism and hyperthyroidism with medical-record confirmed endometrial (EC; all invasive adenocarcinomas) and ovarian cancer (OC; epithelial ovarian or peritoneal cancers) in Nurses' Health Study (NHS) from 1976 to 2010 and NHSII from 1989 to 2011. Cox proportional hazard models were used to estimate multivariable rate ratios (RRs) and 95% confidence intervals based on pooled cohort data. Results. We confirmed 1314 incident cases of EC and 1150 cases of OC. Neither a history of hypothyroidism nor hyperthyroidism was significantly associated with risk of EC or OC. However, having a history of hypothyroidism for 8+ years (median) was nonsignificantly inversely associated with EC (RR = 0.81; 95% CI = 0.63-1.04; P-trend with history duration = 0.11) and OC (RR = 0.87, 95% CI = 0.66-1.15; P-trend = 0.13). Having a history of hyperthyroidism for 6+ years (median) was non-significantly positively associated with EC (RR = 1.69; 95% CI = 0.86-3.30; P-trend = 0.12) but not OC (RR = 1.12; 95% CI = 0.46-2.72; P-trend = 0.95). Conclusions. A history of hypothyroidism or hyperthyroidism was not significantly associated with risk of EC or OC.

Nuclear monomeric integrin αv in cancer cells is a coactivator regulated by thyroid hormone

Thyroid hormone induces tumor cell and blood vessel cell proliferation via a cell surface receptor on heterodimeric integrin αvβ3. We investigated the role of thyroid hormone-induced internalization of nuclear integrin αv monomer. Physiological concentration of thyroxine (free T4, 10(-10) M), but not 3,5,3'-triiodo-l-thyronine (T3), induced cellular internalization and nuclear translocation of integrin αv monomer in human non-small-cell lung cancer (H522) and ovarian carcinoma (OVCAR-3) cells. T4 did not complex with integrin αv monomer during its internalization. The αv monomer was phosphorylated by activated ERK1/2 when it heterodimerized with integrin β3 in vitro. Nuclear αv complexed with transcriptional coactivator proteins, p300 and STAT1, and with corepressor proteins, NCoR and SMRT. Nuclear αv monomer in T4-exposed cells, but not integrin β3, bound to promoters of specific genes that have important roles in cancer cells, including estrogen receptor-α, cyclooxygenase-2, hypoxia-inducible factor-1α, and thyroid hormone receptor β1 in chromatin immunoprecipitation assay. In summary, monomeric αv is a novel coactivator regulated from the cell surface by thyroid hormone for the expression of genes involved in tumorigenesis and angiogenesis. This study also offers a mechanism for modulation of gene expression by thyroid hormone that is adjunctive to the nuclear hormone receptor (TR)-T3 pathway.

Prenatal iodine deficiency results in structurally and functionally immature lungs in neonatal rats

Maternal hypothyroidism affects postnatal lung structure. High prevalence of hypothyroxinemia (low T4, normal T3) in iodine-deficient pregnant women and associated risk for neuropsychological development along with high infant/neonatal mortality ascribed to respiratory distress prompted us to study the effects of maternal hypothyroxinemia on postnatal lung development. Female Sprague Dawley rats were given a low-iodine diet (LID) with 1% KClO4in drinking water for 10 days, to minimize thyroid hormone differences. Half of these rats were continued on iodine-deficient diet; ID (LID with 0.005% KClO4) for 3 mo, whereas the rest were switched to an iodine-sufficient diet; IS [LID + potassium iodide (10 μg iodine/20 g of diet + normal drinking water)]. Pups born to ID mothers were compared with age-matched pups from IS mothers at postnatal days 8 (P8) and 16 (P16) ( n = 6–8/group). ID pups had normal circulating T3 but significantly low T4 levels ( P < 0.05) and concomitantly approximately sixfold higher thyroid hormone receptor-β mRNA in alveolar epithelium. Lung histology revealed larger and irregularly shaped alveoli in ID pups relative to controls. Lung function was assessed at P16 using a double-chambered plethysmograph and observed reduced tidal volume, peak inspiratory and expiratory flow, and dynamic lung compliance in ID pups compared with IS pups. Significant lowering of surfactant protein (SP)-B and SP-C mRNA and protein found in ID pups at P16. ID pups had 16-fold lower matrix metalloproteinase-9 mRNA levels in their alveolar epithelium. In addition, mRNA levels of thyroid transcription factor-1 and SP-D were significantly higher (3-fold) compared with IS pups. At P16, significantly lower levels of SP-B and SP-C found in ID pups may be responsible for immature lung development and reduced lung compliance. Our data suggest that maternal hypothyroxinemia may result in the development of immature lungs that, through respiratory distress, could contribute to the observed high infant mortality in ID neonates.

Thyroid hormone receptors promote metastasis of human hepatoma cells via regulation of TRAIL

Although accumulating evidence has confirmed the important roles of thyroid hormone (T(3)) and its receptors (TRs) in tumor progression, the specific functions of TRs in carcinogenesis remain unclear. In the present study, tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) was directly upregulated by T(3) in TR-overexpressing hepatoma cell lines. TRAIL is an apoptotic inducer, but it can nonetheless trigger non-apoptotic signals favoring tumorigenesis in apoptosis-resistant cancer cells. We found that TR-overexpressing hepatoma cells treated with T(3) were apoptosis resistant, even when TRAIL was upregulated. This apoptotic resistance may be attributable to simultaneous upregulation of Bcl-xL by T(3), because (1) knockdown of T(3)-induced Bcl-xL expression suppressed T(3)-mediated protection against apoptosis, and (2) overexpression of Bcl-xL further protected hepatoma cells from TRAIL-induced apoptotic death, consequently leading to TRAIL-promoted metastasis of hepatoma cells. Moreover, T(3)-enhanced metastasis in vivo was repressed by the treatment of TRAIL-blocking antibody. Notably, TRAIL was highly expressed in a subset of hepatocellular carcinoma (HCC) patients, and this high-level expression was significantly correlated with that of TRs in these HCC tissues. Together, our findings provide evidence for the existence of a novel mechanistic link between increased TR and TRAIL levels in HCC. Thus, TRs induce TRAIL expression, and TRAIL thus synthesized acts in concert with simultaneously synthesized Bcl-xL to promote metastasis, but not apoptosis.

What the obstetrician/gynecologist should know about thyroid disorders

Thyroid disease is a common disorder faced by women of all ages. Because of its high incidence in women, recognizing and treating thyroid dysfunction often becomes the responsibility of the obstetrician/gynecologist. It is important that women's healthcare providers understand how the thyroid's function changes as a woman enters her reproductive years, as well as during pregnancy and menopause. Current guidelines for diagnosing and managing thyroid dysfunction and recommended treatment strategies are discussed in this review.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this educational activity, the obstetrician/gynecologist should be better able to evaluate normal thyroid physiology and pathophysiology of thyroid dysfunction; assess appropriate screening options for their patients; and diagnose and manage thyroid disorders common among reproductive-aged women.

Thyroid receptor: roles in cancer

The thyroid hormone receptors, encoded by the TRalpha and TRbeta genes, are ligand-dependent transcription factors that belong to the nuclear receptor superfamily. In addition to the role of these receptors in growth, development and metabolism, there is increasing evidence that they also inhibit transformation and act as tumor suppressors. Aberrant TR action, as well as receptor silencing, are common events in human cancer, and TRs also have an important role in tumor progression in experimental animal models, suggesting that these receptors constitute a novel therapeutic target in cancer. This review highlights recent studies on mechanisms by which loss of expression and/or function of these receptors results in a selective advantage for cellular transformation, tumor development and metastatic growth.

Prolactin signaling through the short isoform of the mouse prolactin receptor regulates DNA binding of specific transcription factors, often with opposite effects in different reproductive issues

BACKGROUND

It has been well established that prolactin (PRL) signals through the long form of its receptor (PRL-RL) and activates the Jak/Stat pathway for transcription of PRL target genes. However, signaling pathways mediated through the short PRL-R isoform (PRL-RS) remains controversial. Our recent finding that PRL signaling through PRL-RS represses two transcription factors critical for follicular development lead us to examine other putative PRL/PRL-RS target transcription factors in the decidua and ovary, two well-known target tissues of PRL action in reproduction.

METHODS

In this investigation we used mice expressing PRL-RS on a PRL-R knockout background and a combo protein/DNA array to study the transcription factors regulated by PRL through PRL-RS only.

RESULTS

We show that PRL activation of the PRL-RS receptor either stimulates or inhibits the DNA binding activity of a substantial number of transcription factors in the decidua as well as ovary. We found few transcription factors to be similarly regulated in both tissues, while most transcription factors are oppositely regulated by PRL in the decidua and ovary. In addition, some transcription factors are regulated by PRL only in the ovary or only in the decidua. Several of these transcription factors are involved in physiological pathways known to be regulated by PRL while others are novel.

CONCLUSION

Our results clearly indicate that PRL does signal through PRL-RS in the decidua as well as the ovary, independently of PRL-RL, and activates/represses transcription factors in a tissue specific manner. This is the first report showing PRL/PRL-RS regulation of specific transcription factors. Many of these transcription factors were not previously known to be PRL targets, suggesting novel physiological roles for this hormone.

Receptors for thyroid-stimulating hormone and thyroid hormones in human ovarian tissue

Dysfunction in thyroid regulation can cause menstrual and ovulatory disturbances, the mechanism of which is not clear. The distribution and activity of the thyroid-stimulating hormone (TSHR), and the thyroid hormone receptors (TR) alpha1, alpha2 and beta1 in human ovarian tissue and in granulosa cells was studied using immunohistochemistry, reverse-transcriptase polymerase chain reaction (RT-PCR), quantitative PCR and immunoassays. Strong immunostaining of TSHR, TRalpha1 and TRbeta1 was observed in ovarian surface epithelium and in oocytes of primordial, primary and secondary follicles, with minimal staining in granulosa cells of secondary follicles. Granulosa cells of antral follicles expressed TSHR, TRalpha1 and TRbeta1 proteins. Messenger RNA for all receptors was present in ovarian tissue. Mature human granulosa cells expressed transcripts for 5' deiodinases types 2 and 3, but not type 1, indicating the possibility of conversion of peripheral thyroid hormone thyroxin (T(4)). Granulosa cells stimulated with TSH showed a significant increase in cAMP concentrations after 2 h of culture (P = 0.047), indicating activation through TSHR. Stimulation with T(4) resulted in increased extracellular signal-regulated kinase 1 and 2 activation after 10, 30, 60 min and 24 h. These data demonstrate that TSH and thyroid hormone receptors may participate in the regulation of ovarian function.