Changing Immunochemistry Platforms: Thyroid Function Test Comparison and Reference Intervals Based on Clinical Needs

Background

Diagnosis of thyroid dysfunction relies on thyroid stimulating hormone (TSH), free thyroxine (FT4), and free tri-iodothyronine (FT3) tests against valid reference intervals (RIs). We changed the immunoassay platform from Abbott Architect to Siemens Atellica and aimed to establish Atellica RIs based on laboratory information system (LIS) patient data.

Methods

Atellica thyroid hormone immunoassays were verified against those of Architect. Real-life patient results were retrieved from LIS. A single result per patient dataset was used to establish the RIs by the indirect method.

Results

Atellica and Architect assays correlated well but Atellica showed a positive bias between 13% and 53%, the largest for FT4. Variations of the Atellica assays were ≤4%. The 95% Atellica RIs were 0.4–3.8 mU/L for TSH, 0.9–1.6 ng/dL for FT4, and 227–416 pg/dL for FT3. Considering the accumulating clinical experience with Atellica, the RIs for clinical use were adjusted as 0.5–4.0 mU/L, 0.9–1.8 ng/dL, and 169–409 pg/dL, respectively.

Conclusions

We verified thyroid hormone RIs for Atellica by the indirect method for the first time. Our model proved reliable for selecting results of presumably healthy individuals from LIS data. Critical review of the RIs with local endocrinologists is essential.

FOXL2 in adult-type granulosa cell tumour of the ovary: oncogene or tumour suppressor gene?

A recurrent mutation in FOXL2 (c.402C>G; p.C134W) is present in over 95% of adult-type granulosa cell tumours (AGCTs). In contrast, various loss-of-function mutations in FOXL2 lead to the development of blepharophimosis, ptosis, and epicanthus inversus syndrome (BPES). BPES is characterised by an eyelid malformation often accompanied with primary ovarian insufficiency. Two recent studies suggest that FOXL2 C402G is a gain- or change-of-function mutation with altered DNA-binding specificity. Another study proposes that FOXL2 C402G is selectively targeted for degradation, inducing somatic haploinsufficiency, suggesting its role as a tumour suppressor. The latter study relies on data indicative of an FOXL2 allelic imbalance in AGCTs. Here we present RNA-seq data as genetic evidence that no real allelic imbalance is observed at the transcriptomic level in AGCTs. Additionally, there is no loss of protein expression in tumours harbouring the mutated allele. These data and other features of this mutation compared to other oncogenes and tumour suppressor genes argue strongly against FOXL2 being a tumour suppressor in this context. Given the likelihood that FOXL2 C402G is oncogenic, targeting the variant protein or its downstream consequences is the most viable path forward to identifying an effective treatment for this cancer. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Quality benchmarking of smartphone laboratory medicine applications: comparison of laboratory medicine specialists' and non-laboratory medicine professionals' evaluation

OBJECTIVES

There are many mobile health applications (apps) now available and some that use in some way laboratory medicine data. Among them, patient-oriented are of the lowest content quality. The aim of this study was to compare the opinions of non-laboratory medicine professionals (NLMP) with those of laboratory medicine specialists (LMS) and define the benchmarks for quality assessment of laboratory medicine apps.

METHODS

Twenty-five volunteers from six European countries evaluated 16 selected patient-oriented apps. Participants were 20-60 years old, 44% were females, with different educational degrees, and no professional involvement in laboratory medicine. Each participant completed a questionnaire based on the Mobile Application Rating Scale (MARS) and the System Usability Scale, as previously used for rating the app quality by LMS. The responses from the two groups were compared using the Mann-Whitney U test and Spearman correlation.

RESULTS

The median total score of NLMP app evaluation was 2.73 out of 5 (IQR 0.95) compared to 3.78 (IQR 1.05) by the LMS. All scores were statistically significantly lower in the NLMP group (p<0.05), except for the item Information quality (p=0.1631). The suggested benchmarks for a useful appear: increasing awareness of the importance and delivering an understanding of persons' own laboratory test results; understandable terminology; easy to use; appropriate graphic design, and trustworthy information.

CONCLUSIONS

NLMP' evaluation confirmed the low utility of currently available laboratory medicine apps. A reliable app should contain trustworthy and understandable information. The appearance of an app should be fit for purpose and easy to use.

Functional Profiling of FSH and Estradiol in Ovarian Granulosa Cell Tumors

Adult-type granulosa cell tumors (AGCTs) are sex-cord derived neoplasms with a propensity for late relapse. Hormonal modulators have been used empirically in the treatment of recurrent AGCT, albeit with limited success. To provide a more rigorous foundation for hormonal therapy in AGCT, we used a multimodal approach to characterize the expressions of key hormone biomarkers in 175 tumor specimens and 51 serum samples using RNA sequencing, immunohistochemistry, RNA in situ hybridization, quantitative PCR, and circulating biomarker analysis, and correlated these results with clinical data. We show that FSH receptor and estrogen receptor beta (ERβ) are highly expressed in the majority of AGCTs, whereas the expressions of estrogen receptor alpha (ERα) and G-protein coupled estrogen receptor 1 are less prominent. ERβ protein expression is further increased in recurrent tumors. Aromatase expression levels show high variability between tumors. None of the markers examined served as prognostic biomarkers for progression-free or overall survival. In functional experiments, we assessed the effects of FSH, estradiol (E2), and the aromatase inhibitor letrozole on AGCT cell viability using 2 in vitro models: KGN cells and primary cultures of AGCT cells. FSH increased cell viability in a subset of primary AGCT cells, whereas E2 had no effect on cell viability at physiological concentrations. Letrozole suppressed E2 production in AGCTs; however, it did not impact cell viability. We did not find preclinical evidence to support the clinical use of aromatase inhibitors in AGCT treatment, and thus randomized, prospective clinical studies are needed to clarify the role of hormonal treatments in AGCTs.

Abstract 774: Anti-Müllerian hormone type II receptor (AMHRII) found expressed in human non-gynecological solid tumors, suggesting potential broader applications for anti-AMHRII-based therapy

The anti-Müllerian hormone (AMH) belongs to the TGF-β family and plays a key role during fetal sexual development. It has been shown that AMH inhibits proliferation and induces apoptosis of AMH type II receptor (AMHRII) -positive tumor cells, especially progenitor cancer cells. Moreover, various reports have described the expression of AMHRII in human gynecologic cancers including ovarian tumors. Based on qRT-PCR test results, which were confirmed by a specific In-Situ Hybridization (ISH) assay, AMHRII mRNA could be detected only in normal ovary, testis and adrenal gland tissue, and at lower levels in pancreas and stomach. However, when a tissue microarray of solid tumor samples was tested with ISH assay, AMHRII mRNA was surprisingly detected in several primary cancer tissues including melanoma, lung, head and neck, colorectal and breast cancers. For example, a large ISH study involving 58 colorectal cancer samples demonstrated AMHRII expression in 55% of cases. AMHRII protein expression was confirmed by ImmunoHistoChemistry (IHC) in gynecological cancer samples including 179 out of 210 (85%) Granulosa Cell Tumor samples and 55 out of 80 (69 %) Epithelial Ovarian Cancers. In patients with gynecological cancers pre-screened by IHC for inclusion in a Phase Ia/Ib clinical trial of GM102, an anti-AMHRII monoclonal antibody, AMHRII positive membrane expression was detected in 116 out of 166 (70%) archived tumor tissues. Using the same IHC protocol, over 1000 frozen samples covering 16 different cancer types were tested, which demonstrated AMHRII expression in over 50% of hepatocarcinoma, colorectal, lung and renal cancer samples. No AMHRII expression was observed in 75 neuroendocrine lung tumor samples nor in 18 non-Hodgkin lymphoma samples tested. On a small panel of frozen ovarian (11) and colorectal (9) cancer samples using an immunofluorescence assay with an AlexaFluor488-conjugated GM102 antibody, AMHRII expression was confirmed on the matching fresh tissue samples, previously detected by IHC in their fixed counterpart samples. Preliminary FACS analysis of fresh ovarian and colorectal tumor samples have demonstrated comparable expression levels with mean values of 50,000 and 40,000 AMHRII receptors per cell, respectively. In conclusion, the results presented above, using a variety of detection methods and systems, have consistently shown that AMHRII is expressed in many different histological types of solid tumors. These results suggest that this embryonic receptor could be a suitable target for selective antitumor agents such as GM102.

Citation Format: Jean-Marc M. Barret, Didier Meseure, Guillaume Bataillon, Noora Andersson, Aurélie Auguste, Olivier Dubreuil, Anniina Färkkilä, Emeline Perrial, Celine Bossard, Emily Loison, Anne Jarry, André Nicolas, Fanny Lemée, Solenne Gaillard, Mehdi Lahmar, Mikko Anttonen, Gabriel Champenois, Charles Dumontet, Isabelle Ray-Coquard, Alexandra Leary, Isabelle Tabah-Fisch, Anne Vincent-Salomon, Jean-François F. Prost. Anti-Müllerian hormone type II receptor (AMHRII) found expressed in human non-gynecological solid tumors, suggesting potential broader applications for anti-AMHRII-based therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 774.

Systematic drug sensitivity testing reveals synergistic growth inhibition by dasatinib or mTOR inhibitors with paclitaxel in ovarian granulosa cell tumor cells

OBJECTIVE

Resistance to standard chemotherapy poses a major clinical problem in the treatment of ovarian cancer patients. Adult-type granulosa cell tumor (AGCT) is a unique ovarian cancer subtype for which efficient treatment options are lacking in advanced disease. To this end, systematic drug response and transcriptomics profiling were performed to uncover new therapy options for AGCTs.

METHODS

The responses of three primary and four recurrent AGCTs to 230 anticancer compounds were screened in vitro using a systematic drug sensitivity and resistance testing (DSRT) platform, coupled with mRNA sequencing. The responses of the AGCTs were compared with those of human granulosa luteal cells and bone marrow mononuclear cells.

RESULTS

Patient-derived AGCT cells showed selective sensitivity to the Src family tyrosine kinase inhibitor dasatinib. A combination of either dasatinib or an mTOR-inhibitor everolimus with paclitaxel resulted in synergistic inhibition of AGCT cell viability. The key kinase targets of dasatinib and members of the mTOR pathway were constantly expressed at mRNA and protein levels, indicating multikinase signal addictions in the AGCT cells. Transcriptomic characterization of the tumors revealed no known oncogenic mutations, suggesting that the drug sensitivity of AGCTs was rather conveyed by selective target expression.

CONCLUSIONS

We used a systematic functional approach to reveal novel treatment options for a unique gynecological cancer. The selective synergy found between taxanes and dasatinib or mTOR inhibitors warrants further clinical investigations of these combinations in relapsed or aggressive AGCTs and demonstrate that high-throughput drug screening and molecular profiling can provide an effective approach to uncover new therapy options.

Molecularly Defined Adult Granulosa Cell Tumor of the Ovary: The Clinical Phenotype

The histopathologic features of adult granulosa cell tumors (AGCTs) are relatively nonspecific, resulting in misdiagnosis of other cancers as AGCT, a problem that has not been well characterized. FOXL2 mutation testing was used to stratify 336 AGCTs from three European centers into three categories: 1) FOXL2 mutant molecularly defined AGCT (MD-AGCT) (n = 256 of 336), 2) FOXL2 wild-type AGCT (n = 17 of 336), 3) misdiagnosed other tumor types (n = 63 of 336). All statistical tests were two-sided. The overall and disease-specific survival of the misdiagnosed cases was lower than in the MD-AGCTs (P < .001). The misdiagnosed cases accounted for 71.9% of disease-specific deaths within five years. In the population-based cohort, overall survival of MD-AGCT patients was not different from age-matched, population-based controls. Even though 35.2% of all the MD-AGCT patients in our study experienced a relapse, AGCT is usually an indolent disease. The historical, premolecular data underpinning our clinical understanding of AGCT was likely skewed by inclusion of misdiagnosed cases, and future management strategies should reflect the potential for surgical cure and long survival even after relapse.

Abstract 1700: Dasatinib and everolimus show synergistic growth inhibition with paclitaxel in an ovarian granulosa cell tumor model

Adult-type granulosa cell tumor (AGCT) is a rare form of ovarian cancer characterized by a somatic mutation in FOXL2 (402C&gt;G). Although AGCT is known for its indolent growth, up to 30% of AGCTs recur, and with recurrence the mortality reaches 60-70%. For recurrent tumors, surgery is often infeasible and the current chemotherapy regimen have only modest effect. Therefore, new treatment strategies are needed.

We performed high-throughput drug sensitivity and resistance testing (DSRT) utilizing six patient-derived primary cell cultures (2 primary and 4 recurrent AGCTs), and a human AGCT cell line (KGN). AGCT cells were exposed to 232 investigational compounds and approved chemotherapeutics. Selective efficacy was assessed against healthy bone marrow cells and the most potent compounds were further tested in a combination matrix with paclitaxel in KGN cells. The expression levels of the drug targets were verified by RNA-sequencing, and immunohistochemistry in a tissue microarray of 90 AGCT samples.

The response profiles of the AGCTs and the AGCT cell line were similar, with no significant variation between the primary and recurrent tumors. Inhibitors of survivin, HSP90, mTOR, and SRC exhibited the highest selective efficacies, whereas taxanes were the most potent traditional chemotherapeutics. The combination of SRC-inhibitor dasatinib and paclitaxel showed unanticipated synergistic growth inhibition already at low doses, with a 50% increase in sensitivity compared to the effects of either compound alone in AGCT cell line. Similarly, mTOR-inhibitors everolimus, PF-04691502, and AZD8055 showed synergy when combined with paclitaxel. Primary targets of these compounds were expressed at both mRNA and protein level, showing an overall similarity across the tested tumors.

This was the first time the DSRT platform was performed on cultures obtained from a solid cancer, providing an intriguing ex vivo tool to identify potential compounds for further clinical testing. The similarity of the drug sensitivity and gene expression profiles across the tumors underline the homogenous nature of AGCT, and suggest the results may be generalized for other AGCTs. Given the suboptimal clinical usability of the current survivin and HSP90 inhibitors, further drug development is needed prior to clinical testing. However, based on the significant synergy found in the present study, clinical trials combining paclitaxel with the readily approved anticancer drugs dasatinib and everolimus are warranted for patients with advanced AGCT.

Citation Format: Ulla-Maija Haltia, Noora Andersson, Bhagwan Yadav, Evgeny Kulesskiy, Anniina Färkkilä, Annika Riska, Leila Unkila-Kallio, Krister Wennerberg, Tero Aittokallio, Mikko Anttonen. Dasatinib and everolimus show synergistic growth inhibition with paclitaxel in an ovarian granulosa cell tumor model. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1700. doi:10.1158/1538-7445.AM2015-1700

Abstract 605: The clinical outcome of patients with FOXL2 402C-&gt;G mutation positive adult-type Granulosa Cell Tumor of the ovary - a population based study with analysis of tissue and plasma ctDNA

Adult-type Granulosa Cell Tumors (AGCTs) are rare ovarian neoplasms comprising of 5% of all ovarian cancers. The FOXL2 (C-&gt;G) C134W mutation has been identified in 95% of all AGCTs, making it a pathognomonic defining feature. The histological diagnosis of AGCT is challenging; false diagnoses have been reported in up to 30-50% of cases in historical series. AGCTs behave unpredictably, and recurrences occur in 30-60% of the patients. The clinical outcome of molecularly defined, FOXL2-mutation positive AGCTs remains unknown.

We conducted a partially prospective, population-based study of 248 AGCT patients diagnosed or treated at Helsinki University Central Hospital, Finland, during 3/1956-10/2013. Clinical data were collected from hospital records and the causes of death from the Finnish Causes of Death registry. FOXL2 mutation was analyzed from DNA extracted from FFPE (n = 171), and fresh tumor tissue samples (n = 51). Histological diagnosis was re-evaluated in Helsinki, and differential diagnostic cases (n = 24) were subjected to a blinded histological review in Vancouver. Serial plasma samples (n = 120) were collected prospectively during 8/2007- 4/2013 from 37 AGCT patients. The extracted ctDNA was preamplified using the C134W FOXL2 Taqman primer/probe. Tissue and plasma DNA were analyzed with Raindance Raindrop digital PCR technology. Statistical analyses were performed with Kaplan-Meier, and comparison of ctDNA positivity to tumor diameter with oneway ANOVA using JMP software.

Of the original cohort, 165 (74%) tumors were positive and 57 (26%) tumors were negative for the FOXL2 402C-&gt;G mutation. Upon pathological review, an alternate diagnosis was set for 35 mutation negative patients in the first review (Helsinki), and for 41 patients in the final review (Vancouver). The vast majority (n = 149, 90%) of the FOXL2 mutation positive AGCT patients were diagnosed at stage I. The 5-, 10, and 15-year disease-specific survival (DSS) rates were 99%, and 93%, and 89% for the FOXL2 positive AGCT patients, compared to 58%, 53%, and 51% for the FOXL2 wild-type/misdiagnosed other tumors (p&lt;0.0001, log-rank test). 51 (31%) of the FOXL2 positive AGCT patients had a recurrence at a median time of 7.6 years (range 1-26 years) after the diagnosis. FOXL2 mutation was detected in the plasma of 17% (n = 8) of samples from patients with primary or recurrent AGCT. ctDNA FOXL2 mutation was more likely detected in patients with large tumors (p = 0.003).

We have characterized the largest population based cohort of AGCT patients, and shown that the outcome of the patients with FOXL2 mutation positive AGCT was superior to those with original AGCT misdiagnosis. ctDNA is a promising tool to diagnose AGCT in a non-invasive manner. Testing FOXL2 mutation should be used as standard of care, especially in differential diagnostic cases.

Citation Format: Anniina Färkkilä, Melissa K. McConechy, Winnie Yang,, Nirit Rozenberg, Noora Andersson, Leila Unkila-Kallio, Ralf Bützow, Blake Gilks, David G. Huntsman, Mikko Anttonen. The clinical outcome of patients with FOXL2 402C-&gt;G mutation positive adult-type Granulosa Cell Tumor of the ovary - a population based study with analysis of tissue and plasma ctDNA. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 605. doi:10.1158/1538-7445.AM2015-605

The clinical utility of serum anti-Müllerian hormone in the follow-up of ovarian adult-type granulosa cell tumors--A comparative study with inhibin B

Ovarian adult-type granulosa cell tumors (AGCTs) require prolonged follow-up, but evidence regarding the optimal follow-up marker is lacking. The objective of our study was to validate the clinical usefulness of serum anti-Müllerian hormone (AMH) and the current marker inhibin B as single and combined markers of AGCTs. We conducted a longitudinal, partially prospective cohort study of 123 premenopausal and postmenopausal AGCT patients with a median follow-up time of 10.5 years (range 0.3-50.0 years). Serum AMH and inhibin B levels were measured from 560 pretreatment and follow-up serum samples by using immunoenzymometric assays. We found that serum AMH and inhibin B levels were significantly elevated in patients with primary or recurrent AGCTs. The levels of both markers positively correlated to tumor size (p < 0.05). AMH and inhibin B performed similarly in receiving operator characteristic analyses; area under the curve (AUC) values were 0.92 [95% confidence interval (CI) 0.88-0.95] for AMH, and 0.94 (95% CI 0.90-0.96) for inhibin B. AMH was highly sensitive (92%) and specific (81%) in detecting a macroscopic AGCT. However, in AUC comparison analyses, the combination of the markers was superior to inhibin B alone. In conclusion, serum AMH is a sensitive and specific marker of AGCT, and either AMH or inhibin B can be monitored during follow-up. However, combining AMH and inhibin B in AGCT patient follow-up improves the detection of recurrent disease.

Combined comparative genomic hybridization and transcriptomic analyses of ovarian granulosa cell tumors point to novel candidate driver genes

Background

Ovarian granulosa cell tumors (GCTs) are the most frequent sex cord-stromal tumors. Several studies have shown that a somatic mutation leading to a C134W substitution in the transcription factor FOXL2 appears in more than 95% of adult-type GCTs. Its pervasive presence suggests that FOXL2 is the main cancer driver gene. However, other mutations and genomic changes might also contribute to tumor formation and/or progression.

Methods

We have performed a combined comparative genomic hybridization and transcriptomic analyses of 10 adult-type GCTs to obtain a picture of the genomic landscape of this cancer type and to identify new candidate co-driver genes.

Results

Our results, along with a review of previous molecular studies, show the existence of highly recurrent chromosomal imbalances (especially, trisomy 14 and monosomy 22) and preferential co-occurrences (i.e. trisomy 14/monosomy 22 and trisomy 7/monosomy 16q). In-depth analyses showed the presence of recurrently broken, amplified/duplicated or deleted genes. Many of these genes, such as AKT1, RUNX1 and LIMA1, are known to be involved in cancer and related processes. Further genomic explorations suggest that they are functionally related.

Conclusions

Our combined analysis identifies potential candidate genes, whose alterations might contribute to adult-type GCT formation/progression together with the recurrent FOXL2 somatic mutation.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1283-0) contains supplementary material, which is available to authorized users.

Abstract 5610: Circulating tumor DNA: FOXL2 402C-G mutation can be identified in plasma from adult granulosa cell tumor patients with recurrent disease

Adult granulosa cell tumors (aGCT) represent 2-5% of all ovarian cancers. Most patients present with stage 1 disease and have a good prognosis, however up to 30% of aGCTs will recur (median=7 years), and 50% of these patients die of aGCT. These women require prolonged surveillance for serum tumor markers. In recent years, the detection of somatic mutations in free circulating tumor DNA (ctDNA) in plasma has been investigated as a non-invasive method to diagnose and monitor different cancers. The analysis of plasma DNA, which is a mixture of ctDNA and normal DNA, can be extended to aGCT patients that are at risk to recur, which would involve testing for the presence of the FOXL2 402C-&gt;G mutation. This mutation is known to be present in 95% of aGCTs; FOXL2 mutation testing is currently being used to aid in tumor differential diagnosis.

FOXL2 mutations in free ctDNA can be detected in the plasma of aGCT patients and may aid in diagnosis and monitoring of patients.

Plasma samples (1-2mL) were extracted for ctDNA using the Qiagen circulating nucleic acid kit. The ctDNA was preamplified for 10 cycles using the C134W FOXL2 Taqman primer/probe, ABI genotyping mix, followed by a 1:5 dilution. Preamplified ctDNA products were subjected to droplet formation and counted on the Raindance Raindrop digital PCR instruments to detect wild type or mutant alleles. All analysis was performed using the Raindrop Analyst V2 software.

Of two aGCT cases tested, both showed detectable plasma ctDNA FOXL2 mutations using Raindance Raindrop digital PCR. For case 1, plasma from two subsequent time points were tested. The FOXL2 mutation was not detected in the first time point, 12 years from diagnosis, at which time the patient had relapsed disease and underwent chemotherapy. Surgery for extensive tumor burden was performed at the second time point, 6 months later, and a 16% allelic frequency of the FOXL2 mutation was detected in the plasma DNA. For case 2, two plasma samples were tested, the first from the primary surgery, the second at relapse two years later. The FOXL2 ctDNA mutation was present at 6% in the recurrent plasma sample, but not at primary diagnosis. The recurrence was originally diagnosed as a high-grade serous ovarian carcinoma, however the tumor was FOXL2 mutation positive and later re-diagnosed as a relapsed aGCT.

The analysis of two cases of aGCT plasma suggests that the pathognomonic aGCT associated FOXL2 mutation is present in recurrent disease. We also show that the presence of a ctDNA FOXL2 mutation confirms the differential diagnosis of recurrent disease. This is the first proof of principle that plasma DNA may be a non-invasive method to detect recurrent aGCT. Plasma samples from a large prospective cohort with primary or recurrent aGCT will be analyzed to test the sensitive of FOXL2 ctDNA to predict tumor burden. These studies will be imperative to determine the utilization of the plasma FOXL2 ctDNA mutation in routine diagnosis.

Citation Format: Melissa K. McConechy, Anniina Farkkila, Winnie Yang, Noora Andersson, Ying Ng, Leila Unkila-Kallio, Jessica N. McAlpine, Blake Gilks, Mikko Anttonen, David G. Huntsman. Circulating tumor DNA: FOXL2 402C-G mutation can be identified in plasma from adult granulosa cell tumor patients with recurrent disease. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5610. doi:10.1158/1538-7445.AM2014-5610

Sensitivity of human granulosa cell tumor cells to epidermal growth factor receptor inhibition

Epidermal growth factor receptor (EGFR) is implicated in the progression of many human cancers, but its significance in ovarian granulosa cell tumor (GCT) pathobiology remains poorly understood. We assessed the EGFR gene copy number, surveyed the mRNA and protein expression patterns of EGFR in 90 adult GCTs, and assessed the in vitro sensitivity of GCT cells to EGFR inhibition. Low-level amplification of EGFR gene was observed in five GCTs and high-level amplification in one sample. EGFR mRNA was robustly expressed in GCTs. Most tumors expressed both unphosphorylated and phosphorylated EGFR protein, but the protein expression did not correlate with clinical parameters, including the risk of recurrence. Small-molecule EGFR inhibitors reduced the EGF-induced activation of EGFR and its downstream signaling molecules at nanomolar doses, but cell viability was reduced, and caspase-3/7 was activated in GCT cells only at micromolar doses. Based on the present results, EGFR is active and abundantly expressed in the majority of GCTs, but probably has only minor contribution to GCT cell growth. Given the high doses of EGFR inhibitors required to reduce GCT cell viability in vitro, they are not likely to be effective for GCT treatment as single agents; they should rather be tested as part of combination therapies for these malignancies.

HER2 and GATA4 are new prognostic factors for early-stage ovarian granulosa cell tumor-a long-term follow-up study

Granulosa cell tumors (GCTs) carry a risk of recurrence also at an early stage, but reliable prognostic factors are lacking. We assessed clinicopathological prognostic factors and the prognostic roles of the human epidermal growth factor receptors (HER 2–4) and the transcription factor GATA4 in GCTs. We conducted a long-term follow-up study of 80 GCT patients with a mean follow-up time of 16.8 years. A tumor-tissue microarray was immunohistochemically stained for HER2–4 and GATA4. Expression of HER2–4 mRNA was studied by means of real time polymerase chain reaction and HER2 gene amplification was analyzed by means of silver in situ hybridization. The results were correlated to clinical data on recurrences and survival. We found that GCTs have an indolent prognosis, with 5-year disease-specific survival (DSS) being 97.5%. Tumor recurrence was detected in 24% of the patients at a median of 7.0 years (range 2.6–18 years) after diagnosis. Tumor stage was not prognostic of disease-free survival (DFS). Of the molecular prognostic factors, high-level expression of HER2, and GATA4, and high nuclear atypia were prognostic of shorter DFS. In multivariate analyses, high-level coexpression of HER2 and GATA4 independently predicted DFS (hazard ratio [HR] 8.75, 95% CI 2.20–39.48, P = 0.002). High-level expression of GATA4 also predicted shorter DSS (HR 3.96, 95% CI 1.45–12.57, P = 0.006). In multivariate analyses, however, tumor stage (II–III) and nuclear atypia were independent prognostic factors of DSS. In conclusion HER2 and GATA4 are new molecular prognostic markers of GCT recurrence, which could be utilized to optimize the management and follow-up of patients with early-stage GCTs.

Serum vascular endothelial growth factor A (VEGF) is elevated in patients with ovarian granulosa cell tumor (GCT), and VEGF inhibition by bevacizumab induces apoptosis in GCT in vitro

CONTEXT

Ovarian granulosa cell tumors (GCT) are highly vascularized and express vascular endothelial growth factor A (VEGF) and its functional receptor VEGF receptor 2 (VEGFR-2). Angiogenesis inhibitors have been used in the treatment of ovarian carcinomas, whereas their roles in GCT remain unknown.

OBJECTIVE

The aim was to assess serum levels of VEGF and endostatin, an endogenous angiogenesis inhibitor, in GCT patients and to study the effect of bevacizumab (BVZ), a VEGF-binding monoclonal antibody, on human GCT cells in vitro.

DESIGN

Using ELISA, we measured soluble VEGF and endostatin in the sera of 54 GCT patients and in conditioned media from cultures of 14 primary GCT and an established GCT cell line (KGN). The expression of activated VEGFR-2 was analyzed in GCT tissues using immunohistochemistry. GCT cells were treated with BVZ and analyzed for cell number and apoptosis.

RESULTS

Serum VEGF was elevated in GCT patients, and the levels significantly decreased after tumor removal (P < 0.05), whereas serum endostatin levels changed conversely. Human GCT expressed activated VEGFR-2 protein, and the level of expression was associated with tumor VEGF and vascularization. In addition, the cultured GCT cells produced significant amounts of VEGF but not endostatin. Treatment of KGN cells with BVZ significantly reduced the number of viable cells by 41% and induced a 3.3-fold increase in apoptosis. Furthermore, BVZ induced a mean 2.6-fold increase in apoptosis in six primary GCT cell cultures studied.

CONCLUSIONS

These data suggest an autocrine role for VEGF in GCT and encourage clinical studies on anti-VEGF treatments in this disease.

Transcription factor FOXL2 protects granulosa cells from stress and delays cell cycle: role of its regulation by the SIRT1 deacetylase

FOXL2 is a transcription factor that is essential for ovarian function and maintenance, the germline mutations of which are responsible for the Blepharophimosis Ptosis Epicanthus-inversus Syndrome (BPES), often associated with premature ovarian failure. Recent evidence has linked FOXL2 downregulation or somatic mutation (p.Cys134Trp) to cancer, although underlying molecular mechanisms remain unclear. Using a functional genomic approach, we find that FOXL2 modulates cell-cycle regulators in a way which tends to induce G1 arrest. Indeed, FOXL2 upregulation promotes cell accumulation in G1 phase and protects cells from oxidative damage, notably by promoting oxidized DNA repair and by increasing the amounts of anti-oxidant agent glutathione. In agreement with clinical observations, we find that FOXL2-mutated versions leading to BPES along with ovarian dysfunction mostly fail to transactivate cell-cycle and DNA repair targets, whereas mutations leading to isolated craniofacial defects (and normal ovarian function) activate them correctly. Interestingly, these assays revealed a mild promoter-specific hypomorphy of the tumor-associated mutation (p.Cys134Trp). Finally, the SIRT1 deacetylase suppresses FOXL2 activity on targets linked to cell-cycle and DNA repair in a dose-dependent manner. Accordingly, we find that SIRT1 inhibition by nicotinamide limits proliferation, notably by increasing endogenous FOXL2 amount/activity. The body of evidence presented here supports the idea that FOXL2 plays a key role in granulosa cell homeostasis, the failure of which is central to ovarian ageing and tumorigenesis. As granulosa cell tumors respond poorly to conventional chemotherapy, our findings on the deacetylase inhibitor nicotinamide provide an interesting option for targeted therapy.

GATA4 deficiency impairs ovarian function in adult mice

Transcription factor GATA4 is expressed in granulosa cells and, to a lesser extent, in other ovarian cell types. Studies of mutant mice have shown that interactions between GATA4 and its cofactor, ZFPM2 (also termed FOG2), are required for proper development of the fetal ovary. The role of GATA4 in postnatal ovarian function, however, has remained unclear, in part because of prenatal lethality of homozygous mutations in the Gata4 gene in mice. To circumvent this limitation, we studied ovarian function in two genetically engineered mouse lines: C57BL/6 (B6) female mice heterozygous for a Gata4-null allele, and 129;B6 female mice in which Gata4 is deleted specifically in proliferating granulosa cells using the Cre-loxP recombination system and Amhr2-cre. Female B6 Gata4(+/-) mice had delayed puberty but normal estrous cycle lengths and litter size. Compared to wild-type mice, the ovaries of gonadotropin-stimulated B6 Gata4(+/-) mice were significantly smaller, released fewer oocytes, produced less estrogen, and expressed less mRNA for the putative GATA4 target genes Star, Cyp11a1, and Cyp19. Gata4 conditional knockout (cKO) mice had a more severe phenotype, including impaired fertility and cystic ovarian changes. Like Gata4(+/-) mice, the ovaries of gonadotropin-stimulated cKO mice released fewer oocytes and expressed less Cyp19 than those of control mice. Our findings, coupled with those of other investigators, support the premise that GATA4 is a key transcriptional regulator of ovarian somatic cell function in both fetal and adult mice.

Vascular endothelial growth factor (VEGF) and its receptor VEGFR-2 are highly expressed in ovarian granulosa cell tumors

OBJECTIVE

Ovarian granulosa cell tumors (GCTs) are hormonally active sex cord stromal tumors accounting for 3-5% of all ovarian cancers. These tumors are generally diagnosed at an early stage but there is a high risk of recurrence, associated with high mortality. Treatment of recurrent GCTs is difficult, and biologically targeted treatment modalities are lacking. GCTs are highly vascularized, and angiogenic factors most probably play a role in their pathology. Vascular endothelial growth factor (VEGF) is a key regulator of tumor angiogenesis, but in GCTs, the role of VEGF and its receptors VEGFR-1 (FLT1) and VEGFR-2 (KDR) remains largely unknown. Our objective is to study the expression of VEGF and its receptors in human GCTs.

METHODS

We analyzed GCTs from 106 patients for the expressions of VEGF and its receptors utilizing tumor tissue microarray, tumor mRNA, and patient serum samples.

RESULTS

We found that VEGF and its main biologically active receptor VEGFR-2 were highly expressed in primary and recurrent GCTs, when compared with normal granulosa-lutein cells. The expression of VEGF correlated positively to tumor microvessel density and to VEGFR-2 expression at the protein (P<0.05) and mRNA (P<0.05) levels. In contrast to VEGFR-2, the expression of VEGFR-1 was weak. Tumor VEGF protein expression was not prognostic for recurrence, however, we found high levels of circulating VEGF in the serum of patients with primary GCT.

CONCLUSIONS

The results suggest an important role of VEGF and VEGFR-2 in GCT pathology and support the possibility of applying novel VEGF- or VEGFR-2-targeted treatments to patients with GCT.

GATA4 protects granulosa cell tumors from TRAIL-induced apoptosis

Disturbances in granulosa cell apoptosis have been implicated in the pathogenesis of human granulosa cell tumors (GCTs). Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a potent cytokine that induces apoptosis in a variety of malignancies without toxic effects on benign cells. The aim of this study was to investigate the expression and functionality of the TRAIL receptors DR4 and DR5 in human GCTs. Additionally, we examined the role of GATA4, a transcription factor expressed in normal and malignant granulosa cells, in TRAIL-induced GCT apoptosis. For this purpose, a tissue microarray of 80 primary and 12 recurrent GCTs was subjected to immunohistochemistry for DR4 and DR5, and freshly isolated primary GCT cultures were utilized to evaluate the functional effects of TRAIL on GCT cells. To clarify the role of GATA4 in the regulation of TRAIL-induced apoptosis, a human GCT-derived cell line (KGN) was transduced with lentiviral vectors expressing small hairpin RNAs targeting GATA4 or transfected with adenovirus expressing either wild-type or dominant negative mutant GATA4. We found that receptors DR4 and DR5 are expressed in a vast majority of GCTs as well as in primary GCT cultures, and that TRAIL induces apoptosis in the primary GCT cultures. Moreover, we showed that overexpressing GATA4 protects GCTs from TRAIL-induced apoptosis in vitro, whereas disrupting GATA4 function induces apoptosis and potentiates the apoptotic effect of TRAIL administration. Our results demonstrate that the TRAIL pathway is functional in GCT cells, and suggest that transcription factor GATA4 may function as a survival factor in this ovarian malignancy.

WNT4 is expressed in human fetal and adult ovaries and its signaling contributes to ovarian cell survival

WNT4 plays an important role in female sexual development and ovarian function. WNT4-deficiency leads disturbed development of the internal genitalia in mouse and human, and to a dramatic reduction of mouse oocytes. However, the expression and role of WNT4 in human ovaries is yet unknown. The expression of WNT4 mRNA and protein was studied in human adult and fetal ovaries (gestational ages 12-41 weeks), and the role of WNT4 in oocyte apoptosis was investigated in WNT4-deficient mice. WNT4 mRNA and protein were present in human ovaries throughout fetal development and in different follicular stages in adult ovaries. Compared with wild-type mice, WNT4-deficient mice had a markedly enhanced rate of oocyte apoptosis, with the highest values at gestational ages of 14.5 and 16.5 days post-coitum. The current results support a view that WNT4 may have a role in oocyte selection and follicle formation and maturation in human ovaries.

Proteomics of Thlaspi caerulescens accessions and an inter-accession cross segregating for zinc accumulation

Metal hyperaccumulator plants have previously been characterized by transcriptomics, but reports on other profiling techniques are scarce. Protein profiles of Thlaspi caerulescens accessions La Calamine (LC) and Lellingen (LE) and lines derived from an LCxLE cross were examined here to determine the co-segregation of protein expression with the level of zinc (Zn) hyperaccumulation. Although hydrophobic proteins such as membrane transporters are not disclosed, this approach has the potential to reveal other proteins important for the Zn hyperaccumulation trait. Plants were exposed to metals. Proteins were separated using two-dimensional electrophoresis and those showing differences among accessions, lines or metal exposures were subjected to mass-spectrometric analysis for identification. Crossing decreased the number of different proteins in the lines compared with the parents, more so in the shoots than in the roots, but the frequencies of Zn-responsive proteins were about the same in the accessions and the selection lines. This supports the finding that the Zn accumulation traits are mainly determined by the root and that Zn accumulation itself is not the reason for the co-segregation. This study demonstrates that crossing accessions with contrasting Zn accumulation traits is a potent tool to investigate the mechanisms behind metal hyperaccumulation. Four tentatively identified root proteins showed co-segregation with high or low Zn accumulation: manganese superoxide dismutase, glutathione S-transferase, S-formyl glutathione hydrolase, and translation elongation factor 5A-2. However, these proteins may not be the direct determinants of Zn accumulation. The role of these and other tentatively identified proteins in Zn accumulation and tolerance is discussed.

TRAIL pathway components and their putative role in granulosa cell apoptosis in the human ovary

Extensive apoptotic oocyte reduction occurs during fetal ovarian development. The regulatory pathways responsible for oocyte selection to programmed cell death are, however, poorly understood. The aim of this study was to investigate the potential involvement of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and its death receptors TRAIL-R1/DR4 and TRAIL-R2/DR5 and decoy receptors TRAIL-R3/DcR1 and TRAIL-R4/DcR2 in the apoptotic process characterizing human fetal and adult ovaries. For this purpose, in situ hybridization and immunohistochemistry were applied to human fetal and adult ovarian samples to study the mRNA and protein expression of TRAIL pathway components, and a human granulosa cell tumor-derived cell line (KGN) was used to elucidate functional effects of TRAIL on apoptosis. TRAIL was expressed in human fetal ovary from the 11th week until term. The pro-apoptotic TRAIL-R2/DR5 and the anti-apoptotic TRAIL-R4/DcR2 were also expressed in human ovaries throughout the fetal period. Among the different ovarian cell types, these TRAIL pathway components were mainly localized in the oocytes, and their expression increased towards term. Expression of TRAIL-R1/DR4 and TRAIL-R3/DcR1 was negligible in all of the fetal ovaries studied. Adult ovaries expressed TRAIL, TRAIL-R2/DR5, TRAIL-R3/DcR1 and TRAIL-R4/DcR2 in granulosa cells and oocytes of small primary/secondary follicles as well as in granulosa and theca cells of more developed antral follicles. In KGN cells, TRAIL efficiently induced apoptosis in a dose-dependent manner, and this was blocked by a caspase inhibitor. The results indicate a role of the TRAIL pathway components in the regulation of granulosa cell apoptosis in in vitro and suggest that these factors may have a role in regulating ovarian apoptosis also in vivo.

GATA-4 regulates Bcl-2 expression in ovarian granulosa cell tumors

Excessive cell proliferation and decreased apoptosis have been implicated in the pathogenesis of ovarian granulosa cell tumors (GCTs). We hypothesized that transcription factor GATA-4 controls expression of the antiapoptotic factor Bcl-2 and the cell cycle regulator cyclin D2 in normal and neoplastic granulosa cells. To test this hypothesis, a tissue microarray based on 80 GCTs was subjected to immunohistochemistry for GATA-4, Bcl-2, and cyclin D2, and the data were correlated to clinical and histopathological parameters. In addition, quantitative RT-PCR for GATA-4, Bcl-2, and cyclin D2 was performed on 21 human GCTs. A mouse GCT model was used to complement these studies. The role of GATA-4 in the regulation of Bcl2 and ccdn2 (coding for cyclin D2) was studied by transactivation assays, and by disrupting GATA-4 function with dominant negative approaches in mouse and human GCT cell lines. We found that GATA-4 expression correlated with Bcl-2 and cyclin D2 expression in human and murine GCTs. Moreover, GATA-4 enhanced Bcl-2 and cyclin D2 promoter activity in murine GCT cells. Whereas GATA-4 overexpression up-regulated and dominant negative GATA-4 suppressed Bcl-2 expression in human GCT cells, the effects on cyclin D2 were negligible. Our results reveal a previously unknown relationship between GATA-4 and Bcl-2 in mammalian granulosa cells and GCTs, and suggest that GATA-4 influences granulosa cell fate by transactivating Bcl-2.

Role of the GATA family of transcription factors in endocrine development, function, and disease

The WGATAR motif is a common nucleotide sequence found in the transcriptional regulatory regions of numerous genes. In vertebrates, these motifs are bound by one of six factors (GATA1 to GATA6) that constitute the GATA family of transcriptional regulatory proteins. Although originally considered for their roles in hematopoietic cells and the heart, GATA factors are now known to be expressed in a wide variety of tissues where they act as critical regulators of cell-specific gene expression. This includes multiple endocrine organs such as the pituitary, pancreas, adrenals, and especially the gonads. Insights into the functional roles played by GATA factors in adult organ systems have been hampered by the early embryonic lethality associated with the different Gata-null mice. This is now being overcome with the generation of tissue-specific knockout models and other knockdown strategies. These approaches, together with the increasing number of human GATA-related pathologies have greatly broadened the scope of GATA-dependent genes and, importantly, have shown that GATA action is not necessarily limited to early development. This has been particularly evident in endocrine organs where GATA factors appear to contribute to the transcription of multiple hormone-encoding genes. This review provides an overview of the GATA family of transcription factors as they relate to endocrine function and disease.

GATA-4 is a granulosa cell factor employed in inhibin-alpha activation by the TGF-beta pathway

Part of heterodimeric inhibin, inhibin-alpha is crucial for mammalian ovarian function. Regulation of inhibin-alpha expression in granulosa cells is both endocrine, primarily by follicle-stimulating hormone (FSH), and paracrine, primarily by members of the transforming growth factor beta (TGF-beta) superfamily. Smad proteins transmit TGF-beta signals to the nucleus, but the cooperating transcription factors involved in inhibin-alpha promoter activation remain unknown. Transcription factor GATA-4 regulates inhibin-alpha in gonadal cells, and the FSH cascade activates GATA-4. We hypothesized that the TGF-beta signalling cascade and GATA-4 also cooperate to regulate inhibin-alpha expression. In KK-1 granulosa tumour cells, which resemble normal granulosa cells and express inhibin-alpha, we found that TGF-beta upregulated GATA-4 expression. Transient transfection experiments in KK-1 cells demonstrated that dominant negative GATA-4 variants or mutations of GATA-binding sites in the inhibin-alpha promoter attenuated TGF-beta-induced gene activation. In GATA-4-deficient COS-7 cells, TGF-beta enhanced the expression of the inhibin-alpha promoter only in the presence of exogenous GATA-4. Smad3, but not Smad2, cooperated with GATA-4 in the transcriptional activation of the inhibin-alpha promoter, and immunoprecipitation experiments in KK-1 cells revealed a physical Smad3:GATA-4 interaction. Our data suggest that GATA-4, interacting with Smad3, is a cofactor for TGF-beta signalling to activate inhibin-alpha in granulosa cells.

High GATA-4 expression associates with aggressive behavior, whereas low anti-Müllerian hormone expression associates with growth potential of ovarian granulosa cell tumors

CONTEXT

Granulosa cell tumors (GCTs) are ovarian malignancies that produce estrogens, inhibins, and anti-Müllerian hormone (AMH). The molecular pathogenesis of GCTs is likely to involve defects in the genes regulating normal granulosa cell proliferation during folliculogenesis.

OBJECTIVE

The objective of this study was to test the role of factors regulating the normal granulosa cell function, i.e. AMH, inhibin-alpha, SF-1 (steroidogenic factor-1), and GATA transcription factors in the pathobiology and clinical behavior of GCTs.

DESIGN

We selected randomly a cohort of 80 GCT patients treated at our university hospital during 1971-2003, analyzed protein expression in the tumor samples embedded on a tissue microarray by immunohistochemistry, and correlated the data to clinical and histopathological parameters.

RESULTS

We found no significant differences in the immunoreactivity levels of inhibin-alpha, GATA-6, FOG-2 (friend of GATA-2), or SF-1 in GCTs compared with normal granulosa cells. AMH expression was, however, low (i.e. reduced) in 69% of GCTs and correlated inversely with tumor size (P = 0.0025). In contrast, GATA-4 expression was high (i.e. resembled normal granulosa cells) in 44% of GCTs and correlated positively with clinical stage and recurrence (P = 0.0232 and P = 0.0038, respectively). Fifty of the 80 patients had a follow-up for at least 10 yr, and 13 of them had recurrence(s). In multivariate analysis of recurrence, the high GATA-4 expression remained the only independent factor (risk ratio, 9.2; 95% confidence interval, 2.0-43.3; P = 0.0048).

CONCLUSIONS

The more aggressive GCTs retain a high GATA-4 expression, whereas the larger tumors lose the proliferation-suppressing AMH expression. The high GATA-4 expression in GCTs may serve as a marker of poor prognosis.

The gene disrupted in Marinesco-Sjögren syndrome encodes SIL1, an HSPA5 cochaperone

We identified the gene underlying Marinesco-Sjögren syndrome, which is characterized by cerebellar ataxia, progressive myopathy and cataracts. We identified four disease-associated, predicted loss-of-function mutations in SIL1, which encodes a nucleotide exchange factor for the heat-shock protein 70 (HSP70) chaperone HSPA5. These data, together with the similar spatial and temporal patterns of tissue expression of Sil1 and Hspa5, suggest that disturbed SIL1-HSPA5 interaction and protein folding is the primary pathology in Marinesco-Sjögren syndrome.

Small nuclear RING finger protein expression during gonad development: regulation by gonadotropins and estrogen in the postnatal ovary

Small nuclear RING finger protein (SNURF/RNF4) is a steroid receptor coregulator that is down-regulated in testicular germ cell cancer. In this work, we examined SNURF expression during murine fetal gonad development and postnatal ovarian folliculogenesis by in situ hybridization and immunohistochemical staining. SNURF mRNA was detectable in gonads of both sexes from embryonic 10.5 days post conception onward. SNURF protein localized to gonocytes and somatic Leydig and Sertoli cells of fetal testis and in oogonia and supporting cells of fetal ovary. In murine postnatal ovary, SNURF mRNA and protein were expressed throughout folliculogenesis, peaking in the oocytes of preantral follicles. Lower amounts of SNURF mRNA and protein were also present in granulosa cells of secondary, antral, and preovulatory follicles and in luteal glands. Exposure of immature female mice and rats to gonadotropin from pregnant mare serum and human chorionic gonadotropin did not change dramatically SNURF mRNA levels in ovary. SNURF mRNA expression was increased in ovaries of immature mice treated with diethylstilbestrol, an effect that was blocked by the pure antiestrogen ICI 182,780. SNURF protein was constitutively expressed in oocytes of hypophysectomized rats, and its content was augmented by estradiol in granulosa cells. In granulosa cell culture, SNURF mRNA accumulation was transiently increased by treatment with the LH agonists phorbol myristate and forskolin at 4 h after treatment and at 48 h in differentiated cells expressing markers of the preovulatory phenotype. These results suggest a role for SNURF in fetal germ cell development as well as in oocyte and granulosa cell maturation in an estrogen- and gonadotropin-regulated fashion.

FOG-2 and GATA-4 Are coexpressed in the mouse ovary and can modulate mullerian-inhibiting substance expression

Transcription factor GATA-4 has been suggested to have a role in mammalian gonadogenesis, e.g., through activation of the Müllerian-inhibiting substance (MIS) gene expression. Although the expression of GATA-4 during gonadogenesis has been elucidated in detail, very little is known about FOG-2, an essential cofactor for GATA-4, in ovarian development. We explored in detail the expression of FOG-2 and GATA-4 in the fetal and postnatal mouse ovary and in the fetal testis using Northern blotting, RNA in situ hybridization, and immunohistochemistry. GATA-4 and FOG-2 are evident in the bipotential urogenital ridge, and their expression persists in the fetal mouse ovary; this result is different from earlier reports of GATA-4 downregulation in the fetal ovary. In contrast to ovary, FOG-2 expression is lost in the fetal Sertoli cells along with the formation of the testicular cords, leading to the hypothesis that FOG-2 has a specific role in the fetal ovaries counteracting the transactivation of the MIS gene by GATA-4. In vitro transfection assays verified that FOG-2 is able to repress the effect of GATA-4 on MIS transactivation in granulosa cells. In postnatal ovary, granulosa cells of growing follicles express FOG-2, partially overlapping with the expression of MIS. These data suggest an important role for FOG-2 and the GATA transcription factors in the developing ovary.

Developmental expression and spermatogenic stage specificity of transcription factors GATA-1 and GATA-4 and their cofactors FOG-1 and FOG-2 in the mouse testis

OBJECTIVE

The transcription factors GATA-1 and GATA-4 have been implicated in the regulation of testicular development and function. Their cofactors FOG-1 and FOG-2 are expressed in the gonads, but their cell-specific and developmental expression in the testis remains unresolved. Therefore, we analyzed GATA-1, GATA-4, FOG-1 and FOG-2 expression in detail, from undifferentiated male urogenital ridge to adult testis.

METHODS

Immunohistochemistry and in situ hybridization were applied on mouse testicular samples.

RESULTS

GATA-4 and FOG-2, but not GATA-1 or FOG-1, were expressed as early as in the male urogenital ridge. FOG-2 expression was localized in the Sertoli cells at embryonal day 12.5 (E12.5), but it diminished with advancing fetal testicular development. In E17.5 testis, FOG-2 was present only in the testicular capsule and a subset of fetal Leydig cells. FOG-1 was expressed from E15.5 Sertoli cells onwards, whereas GATA-1 was not detected during the fetal period at all. In the postnatal testis, FOG-2 was abundantly expressed immediately after birth, but in adult testis its expression was predominantly restricted to stage VII-XII seminiferous tubules. Stage specificity was also found for FOG-1, which, similarly to GATA-1, was abundantly expressed in stage VII-XII tubules during adulthood.

CONCLUSIONS

Our results indicate that FOG-2, in addition to GATA-4, has a role in early gonadal development and sexual differentiation, and FOG-1 at later fetal stages, while GATA-1 executes its action postnatally. The findings suggest that, in contrast to the hematopoietic system and the heart, GATA-1 and GATA-4 do not use FOG-1 and FOG-2 respectively as their only cofactors during the early stages of testicular development.

Effects of follicle-stimulating hormone (FSH) and human chorionic gonadotropin in individuals with an inactivating mutation of the FSH receptor

OBJECTIVE

To study the gonadal steroid responses to FSH and hCG in individuals with the inherited Finnish-type inactivating Ala189Val mutation of the FSH receptor gene.

DESIGN

Prospective clinical and descriptive study.

SETTING

University hospital.

PATIENT(S)

Two women and one man homozygous for the Ala189Val mutation of the FSH receptor gene, and ovarian biopsies from four affected and four healthy women, and four normal fetuses.

INTERVENTION(S)

Individuals were treated with increasing doses of recombinant FSH (300 IU/day start, 900 IU/day final) and/or a single dose of hCG (5000 IU). Ovarian biopsies were used in immunohistochemical analyses for detection of aromatase cytochrome P450 and transcription factor GATA-4. In situ 3'-end labeling analyses were used for detection of apoptosis.

MAIN OUTCOME MEASURE(S)

Measurements of serum concentrations of follicle-stimulating hormone, leuteinizing hormone, inhibin A and B, estradiol, testosterone (T), androstenedione, and prolactin, immunostaining for ovarian aromatase, GATA-4, and apoptosis.

RESULT(S)

Administration of FSH had no effect on production of the steroids. Similarly, human chorionic gonadotropin (hCG) treatment, alone or after FSH administration, failed to raise serum steroid concentrations. Ovarian apoptosis was absent, and the expression of transcription factor GATA-4 and aromatase was negligible in the ovarian biopsies from Ala189Val homozygous individuals.

CONCLUSION(S)

The Ala189Val mutation of the FSH receptor gene results in a complete block of FSH action in vivo. Furthermore, the failure of hCG to increase both ovarian estradiol and testosterone secretion emphasizes the possible contribution of FSH in regulating ovarian androgen synthesis, and supports the concept that both gonadotropins are necessary for appropriate ovarian steroidogenesis in humans.

Survival of human ovarian follicles from fetal to adult life: apoptosis, apoptosis-related proteins, and transcription factor GATA-4

The majority of oocytes present in fetal ovaries are depleted before birth, and only about 400 will ovulate during the normal fertile life span. Studies on animals have shown that apoptosis is the mechanism behind oocyte depletion and follicular atresia. In the present study, we investigated the extent and localization of apoptosis in human fetal (aged 13-40 weeks) and adult ovaries. Furthermore, the expression of apoptosis-regulating proteins, bcl-2 and bax, and the relationship of transcription factor GATA-4 were studied. Apoptosis was found in ovarian follicles throughout fetal and adult life. During fetal development, apoptosis was localized mainly to primary oocytes and was highest between weeks 14-28, decreasing thereafter toward term. Expression of bcl-2 was observed only in the youngest fetal ovaries (weeks 13-14), and bax was present in the ovaries throughout the entire fetal period. In adult ovaries, apoptosis was detected in granulosa cells of secondary and antral follicles, and Bcl-2 and bax were expressed from primary follicles onwards. During fetal ovarian development, GATA-4 messenger RNA and protein were localized to the granulosa cells, with expression being highest in the youngest ovaries and decreasing somewhat toward term. The expression pattern of GATA-4 suggests that it may be involved in the mechanisms protecting granulosa cells from apoptosis from fetal to adult life. The results indicate that depletion of ovarian follicles in the human fetus occurs through intrinsic mechanisms of apoptosis in oocytes, and later in adult life the survival of growing follicles may be primarily determined by granulosa cell apoptosis.

Comparison of serous and mucinous ovarian carcinomas: distinct pattern of allelic loss at distal 8p and expression of transcription factor GATA-4

Using comparative genomic hybridization (CGH), we have previously demonstrated frequent loss of 8p, especially its distal part, in ovarian carcinoma. To compare the deletion map of distal 8p in serous and mucinous ovarian carcinomas, we performed allelic analysis with 18 polymorphic microsatellite markers at 8p21-p23. In serous carcinoma, loss of heterozygosity (LOH) was detected in 67% of the samples, and the majority of the carcinomas showed loss of all or most of the informative markers. In contrast, only 21% of mucinous carcinomas showed allelic loss, with only one or two loci showing LOH in each sample. In serous carcinomas, LOH was associated with higher grade tumors. Three distinct minimal common regions of loss could be defined in serous carcinomas (at 8p21.1, 8p22-p23.1, and 8p23.1). Expression of a transcription factor gene, GATA4, located at one of these regions (8p23.1) was studied in serous and mucinous ovarian carcinomas by Northern blotting and immunohistochemical staining of tumor microarray. Expression was found to be lost in most serous carcinomas but retained in the majority of mucinous carcinomas. Our results suggest distinct pathogenetic pathways in serous and mucinous ovarian carcinomas and the presence of more than one tumor suppressor gene at 8p involved in the tumorigenesis of serous carcinoma.

Transcription factors GATA-4 and GATA-6 and a GATA family cofactor, FOG-2, are expressed in human ovary and sex cord-derived ovarian tumors

Previous studies have implicated transcription factors GATA-4 and GATA-6 in the regulation of murine ovarian development and function. In rodents, GATA-4 is expressed in granulosa cells of primary and early antral follicles, whereas GATA-6 is expressed in granulosa cells of late antral follicles and luteal glands. Both transcription factors can be detected in lesser amounts in theca cells and interstitial cells. We have now examined the expression of GATA-4 and GATA-6 in human ovaries, human granulosa-luteal (GL) cells and sex cord-derived tumors. We show by in situ hybridization and immunohistochemistry that GATA-4 and GATA-6 messenger RNA (mRNA) and GATA-4 protein are present in granulosa and theca cells in both preantral and antral follicles. Both human ovarian tissue samples and freshly isolated GL cells derived from preovulatory follicles of gonadotropin-treated women express GATA-4, GATA-6, and FOG-2 transcripts, and GATA-6 mRNA expression in GL cell cultures is stimulated by human CG and 8-bromo-cAMP. The vast majority of granulosa and theca cell tumors examined expressed GATA-4 and GATA-6. We also found that mRNA for FOG-2, a recently discovered regulator of GATA-4, is coexpressed with GATA-4 in human ovary samples, normal granulosa cells, and in sex cord-derived tumors. Our results demonstrate that GATA-4, GATA-6, and FOG-2 are expressed in human ovary and in granulosa and theca cell tumors. Our findings support a role for GATA-binding proteins in human ovarian folliculogenesis. Moreover, these data suggest that GATA factors may contribute to the phenotypes of sex cord-derived ovarian tumors.