Anniina Färkkilä

FOXL2, GATA4, and SMAD3 co-operatively modulate gene expression, cell viability and apoptosis in ovarian granulosa cell tumor cells.

Aberrant ovarian granulosa cell proliferation and apoptosis may lead to granulosa cell tumors (GCT), the pathogenesis of which involves transcription factors GATA4, FOXL2, and SMAD3. FOXL2 gene harbors a point mutation (C134W) in a vast majority of GCTs. GATA4 is abundantly expressed in GCTs and its expression correlates with poor prognosis. The TGF-β mediator SMAD3 promotes GCT cell survival through NF-κB activation, and interacts with FOXL2. Here, we find that the expression patterns of these factors overlap in the normal human ovary and 90 GCTs, and positively correlate with each other and with their mutual target gene CCND2, which is a key factor for granulosa cell proliferation. We have explored the molecular interactions of FOXL2, GATA4, and SMAD3 and their roles in the regulation of CCND2 using co-immunoprecipitation, promoter transactivation, and cell viability assays in human GCT cells. We found that not only SMAD3, but also GATA4 physically interact with both wild type and C134W-mutated FOXL2. GATA4 and SMAD3 synergistically induce a 8-fold increase in CCND2 promoter transactivation, which is 50% reduced by both FOXL2 types. We confirmed that wild type FOXL2 significantly decreases cell viability. Interestingly, GATA4 and SMAD3 caused a marked reduction of GCT cell apoptosis induced by wild type FOXL2. Thus, the effects of GATA4 and SMAD3 on both cell viability and apoptosis are distinct from those of wild type FOXL2; a perturbation of this balance due to the oncogenic FOXL2 mutation is likely to contribute to GCT pathogenesis.

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.

Clinical characteristics and survival of patients with an adult-type ovarian granulosa cell tumor: a 56-year single-center experience.

Objective The objective of this study was to evaluate clinical prognostic factors and survival of patients with ovarian granulosa cell tumors (GCTs) in a long-term follow-up study. Methods A total of 240 adult-type GCTs diagnosed in Helsinki University Central Hospital from 1956 to 2012 were histologically reevaluated. Data were analyzed for several clinical factors in relation to major developments in imaging, surgery, and chemotherapy: the old era (1956–1983) and the new era (1984–2012). Prognostic factors for survival were evaluated in the univariate and multivariate analyses. Results The original diagnosis was confirmed in 187 (77.9%) patients. The International Federation of Gynecology and Obstetrics stage I disease was present in 89.2%; stage II, in 7.0%; stage III, in 3.8%; and stage IV, in 0% of cases. The mean age at diagnosis (52.9 years) and the mean tumor size (10.8 cm) did not change significantly over time. The most common presenting symptom was abnormal bleeding, but 14% were asymptomatic. The mean follow-up period was 15.7 years. Recurrence rate was similar in both eras. The GCT-specific 5-, 10-, and 20-year survival rates were 95.6%, 88.1%, and 79.8% in the old era as well as 97.2%, 94.8%, and 94.8% in the new era, respectively. In the univariate analyses, old era, patient age older than 60 years, tumor size greater than 10 cm, advanced stage, residual tumor, and use of hormonal adjuvant treatment were associated with GCT-related deaths. Prior use of oral contraceptives and history of infertility improved survival rates. In the multivariate analysis, stage was the only independent prognostic factor for GCT-specific survival. Conclusions An accurate histological diagnosis of GCT is essential. Stage IV disease is an extreme rarity. However, tumor stage overcomes other possible clinical prognostic factors for GCT-specific survival. Fertility-sparing surgery, the use of oral contraceptives, or hormonal replacement therapy seems not to be risk factors for survival.

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.

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.

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.

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.

Anti-Müllerian hormone inhibits growth of AMH type II receptor-positive human ovarian granulosa cell tumor cells by activating apoptosis

Ovarian granulosa cell tumors (GCTs) are sex cord stromal tumors that constitute 3–5% of all ovarian cancers. GCTs usually present with an indolent course but there is a high risk of recurrence, which associates with increased mortality, and targeted treatments would be desirable. Anti-Müllerian hormone (AMH), a key factor regulating sexual differentiation of the reproductive organs, has been implicated as a growth inhibitor in ovarian cancer. GCTs and normal granulosa cells produce AMH, but its expression in large GCTs is usually downregulated. Further, as the lack of specific AMH-signaling pathway components leads to GCT development in mice, we hypothesized that AMH inhibits growth of GCTs. Utilizing a large panel of human GCT tissue samples, we found that AMH type I receptors (ALK2, ALK3 and ALK6) and type II receptor (AMHRII), as well as their downstream effectors Smad1/5, are expressed and active in GCTs. AMHRII expression was detected in the vast majority (96%) of GCTs and correlated with AMH mRNA and protein expression. AMH mRNA level was low in large GCTs, confirming previous findings on low-AMH protein expression in large human as well as mouse GCTs. To study the functional role of AMH in this peculiar ovarian cancer, we utilized a human GCT cell line (KGN) and 10 primary GCT cell cultures. We found that the AMH–Smad1/5-signaling pathway was active in these cells, and that exogenous AMH further activated Smad1/5 in KGN cells. Furthermore, AMH treatment reduced the number of KGN cells and primary GCT cells, with increasing amounts of AMH leading to augmented activation of caspase-3 and subsequent apoptosis. All in all, these data support the premise that AMH is a growth inhibitor of GCTs.

Characteristics and outcome of recurrence in molecularly defined adult-type ovarian granulosa cell tumors

OBJECTIVE Adult-type ovarian granulosa cell tumors (AGCTs) have an unpredictable tendency to relapse. In a carefully validated patient cohort, we evaluated the prognostic factors related to AGCT recurrence. METHODS We identified all patients diagnosed with AGCT during 1956-2014 in Helsinki University Hospital, with a minimum follow-up of one year (n=240). After a histological review supplemented with FOXL2 (402C-G) mutation status analysis, we analyzed the clinical data for association with relapse. RESULTS The final cohort included 164 (68%) molecularly defined AGCTs (MD-AGCTs). The majority of the women were postmenopausal (63%), and 92% of tumors were stage I. The median follow-up time was 15.5years. Fifty-two (32%) patients developed tumor recurrence, of whom 55% had successive recurrences. Multiple-site recurrences were common, and nearly half of the recurrences were asymptomatic. The median time to the first relapse was 7.4years, and 75% of relapses occurred within ten years after primary diagnosis. The median disease-free survival was 11.3years. Premenopausal status at initial diagnosis, FIGO stage Ic versus Ia, and tumor rupture associated with relapse. However, tumor rupture was the only independent predictive factor. Of the relapsed patients, 48% died of AGCT in a median time of 15.3years. CONCLUSION Tumor rupture is the strongest predictive factor for recurrence, and these patients might benefit from a more aggressive initial treatment approach. AGCT requires active follow up for 10 to 15years after primary diagnosis, since recurrences may develop late, asymptomatically and in multiple anatomical locations.

GATA factors in endocrine neoplasia.

GATA transcription factors are structurally-related zinc finger proteins that recognize the consensus DNA sequence WGATAA (the GATA motif), an essential cis-acting element in the promoters and enhancers of many genes. These transcription factors regulate cell fate specification and differentiation in a wide array of tissues. As demonstrated by genetic analyses of mice and humans, GATA factors play pivotal roles in the development, homeostasis, and function of several endocrine organs including the adrenal cortex, ovary, pancreas, parathyroid, pituitary, and testis. Additionally, GATA factors have been shown to be mutated, overexpressed, or underexpressed in a variety of endocrine tumors (e.g., adrenocortical neoplasms, parathyroid tumors, pituitary adenomas, and sex cord stromal tumors). Emerging evidence suggests that GATA factors play a direct role in the initiation, proliferation, or propagation of certain endocrine tumors via modulation of key developmental signaling pathways implicated in oncogenesis, such as the WNT/β-catenin and TGFβ pathways. Altered expression or function of GATA factors can also affect the metabolism, ploidy, and invasiveness of tumor cells. This article provides an overview of the role of GATA factors in endocrine neoplasms. Relevant animal models are highlighted.