FSH-regulated gene expression profiles in ovarian tumours and normal ovaries

Gestational exposure to NO2 aggravates placental senescence

Placental senescence is a normal physiological process of placenta, while premature placental senescence has been confirmed to be associated with some adverse pregnancy complications. Epidemiological studies indicate that NO₂ exposure can aggravate placental senescence which is represented by fibrosis and abnormal telomere homeostasis, etc. In this study, pregnant C57BL/6 mice were exposed to NO₂ (2.5 ppm, 5 h/day) daily in a dynamic exposure chamber throughout the gestation period, and were sacrificed at embryonic day 13.5 (E13.5), E15.5 and E18.5. Placenta were harvested and conducted for histopathological examination and telomere evaluation. Our results showed that gestational NO₂ exposure significantly aggravated placental fibrosis and calcification, and up-regulated the related bio-markers (connective tissue growth factor (Ctgf) and transforming growth factor-β1 (Tgf-β1)) at E18.5. In addition, gestational exposure to NO₂ also activated senescence related pathway (p53/p21) at E18.5. Furthermore, gestational NO₂ exposure significantly shortened telomere length at E18.5, and the expression of telomere homeostasis regulation genes telomeric repeat binding factor 1 (Trf1), protection of telomeres 1a (Pot1a) and Pot1b were significantly increased while telomerase reverse transcriptase (Tert) was suppressed after NO₂ exposure at E13.5 or E18.5, respectively. Importantly, DNA methylation status of the 22^nd at E13.5 and 32^nd at E18.5 site in sub-telomeric region of chromosome 1 was significantly altered. Based on the above results, our present study indicated that gestational NO₂ exposure could lead to premature placental senescence during the late trimester of pregnancy via aggravation of fibrosis and telomere length shortening regulated by telomere regulatory enzyme and DNA methylation.

SGK1 in Cancer: Biomarker and Drug Target

Serum- and glucocorticoid-regulated kinases (SGKs) are members of the AGC family of serine/threonine kinases, consisting of three isoforms: SGK1, SGK2, and SGK3. SGK1 was initially cloned as a gene transcriptionally stimulated by serum and glucocorticoids in rat mammary tumor cells. It is upregulated in some cancers and downregulated in others. SGK1 increases tumor cell survival, adhesiveness, invasiveness, motility, and epithelial to mesenchymal transition. It stimulates tumor growth by mechanisms such as activation of K⁺ channels and Ca²⁺ channels, Na⁺/H⁺ exchanger, amino acid and glucose transporters, downregulation of Foxo3a and p53, and upregulation of β-catenin and NFκB. This chapter focuses on major aspects of SGK1 involvement in cancer, its use as biomarker as well as potential therapeutic target.

Inhibition of CDK4/6 as Therapeutic Approach for Ovarian Cancer Patients: Current Evidences and Future Perspectives

Simple Summary

Altered regulation of the cell cycle is a hallmark of cancer. The recent clinical success of the inhibitors of CDK4 and CDK6 has convincingly demonstrated that targeting cell cycle components may represent an effective anti-cancer strategy, at least in some cancer types. However, possible applications of CDK4/6 inhibitors in patients with ovarian cancer is still under evaluation. Here, we describe the possible biological role of CDK4 and CDK6 complexes in ovarian cancer and provide the rationale for the use of CDK4/6 inhibitors in this pathology, alone or in combination with other drugs. This review, coupling basic, preclinical and clinical research studies, could be of great translational value for investigators attempting to design new clinical trials for the better management of ovarian cancer patients.

Abstract

Alterations in components of the cell-cycle machinery are present in essentially all tumor types. In particular, molecular alterations resulting in dysregulation of the G1 to S phase transition have been observed in almost all human tumors, including ovarian cancer. These alterations have been identified as potential therapeutic targets in several cancer types, thereby stimulating the development of small molecule inhibitors of the cyclin dependent kinases. Among these, CDK4 and CDK6 inhibitors confirmed in clinical trials that CDKs might indeed represent valid therapeutic targets in, at least some, types of cancer. CDK4 and CDK6 inhibitors are now used in clinic for the treatment of patients with estrogen receptor positive metastatic breast cancer and their clinical use is being tested in many other cancer types, alone or in combination with other agents. Here, we review the role of CDK4 and CDK6 complexes in ovarian cancer and propose the possible use of their inhibitors in the treatment of ovarian cancer patients with different types and stages of disease.

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.

Vascular Endothelial FSH Receptor, a Target of Interest for Cancer Therapy

Improved molecular understanding of tumor microenvironment has resulted in the identification of various cancer cell targets for diagnostic and therapeutic interventions, including the receptor for the FSH, a glycoprotein hormone responsible for growth, maturation, and function of human reproductive system. The expression and localization of the FSH receptor (FSHR)-protein were associated with the tumor epithelial cells and/or with the peripheral tumor blood vessels. The available evidence indicates that in ovarian cancer, prostate cancer, and breast cancer, the tumor epithelial FSHR promotes proliferation, migration, and invasion of cancer cells. The vascular endothelial FSHR, detected in 11 types of solid tumors and 11 types of sarcomas, is involved in receptor-mediated transendothelial transport of FSH, tumor angiogenesis, and vascular remodeling. In contrast to intratumor vessels, which are abnormal and disorganized, the FSHR-positive blood microvessels are arranged in a hierarchical pattern: arterioles-capillaries-venules. The FSHR-positive blood vessels make connections between the intratumor vessels and the general blood circulation of patients. In this mini-review, I summarize these studies and discuss the rationale for developing a strategy for cancer therapy based on FSHR expressed on the luminal endothelial cell surface of blood vessels located in the peritumoral area rather than endothelial markers expressed in the core of tumors. Because FSHR is a common marker of peritumoral vessels, therapeutic agents coupled to anti-FSHR humanized antibodies should in principle be applicable to a wide range of tumor types.

Knockdown of the long non-coding RNA HOTTIP inhibits colorectal cancer cell proliferation and migration and induces apoptosis by targeting SGK1

More and more long non-coding RNA (lncRNA) might be serve as molecular biomarkers for tumor cell progression. HOTTIP has been recently revealed as oncogenic regulator in several cancers. However, it remains unclear about whether and how HOTTIP regulates Colorectal cancer (CRC). In the present study, we assayed the expression of HOTTIP in CRC tissues and cell lines, and detected CRC cells (HCT-116 and SW620) proliferation, migration, and apoptosis when HOTTIP was knocked down. Furthermore, we discovered the underlying mechanism. The level of HOTTIP was higher in CRC tissues and in CRC cells compared with adjacent normal tissues and normal colon tissue cell. Knockdown of HOTTIP inhibited the cell proliferation migration and induced apoptosis in HCT-116 and SW620 cell lines. In addition, luciferase reporter assay suggested that knockdown of HOTTIP could target decreasing the expression of Serum- and glucocorticoid-inducible kinase 1 (SGK1) gene, and we subsequently verified that up-regulation of the SGK1 gene promoted cell proliferation and migration and inhibited cell apoptosis in HCT-116 and SW620 cell lines. Furthermore, Knockdown of HOTTIP significantly suppressed the expression of GSK3β, β-catenin, c-myc, Vimentin and MMP-7, and increased the expression of E-cadherin, FoxO3a, p27 and Bim proteins in HCT-116 and SW620 cell lines, and up-regulation of the SGK1 emerged the opposite effect with knockdown of HOTTIP. The data described in this study suggest that HOTTIP may be an oncogene and a potential target in CRC.

Antibody Selection for Cancer Target Validation of FSH-Receptor in Immunohistochemical Settings

BACKGROUND

The follicle-stimulating hormone (FSH)-receptor (FSHR) has been reported to be an attractive target for antibody therapy in human cancer. However, divergent immunohistochemical (IHC) findings have been reported for FSHR expression in tumor tissues, which could be due to the specificity of the antibodies used.

METHODS

Three frequently used antibodies (sc-7798, sc-13935, and FSHR323) were validated for their suitability in an immunohistochemical study for FSHR expression in different tissues. As quality control, two potential therapeutic anti-hFSHR Ylanthia® antibodies (Y010913, Y010916) were used. The specificity criteria for selection of antibodies were binding to native hFSHR of different sources, and no binding to non-related proteins. The ability of antibodies to stain the paraffin-embedded Flp-In Chinese hamster ovary (CHO)/FSHR cells was tested after application of different epitope retrieval methods.

RESULTS

From the five tested anti-hFSHR antibodies, only Y010913, Y010916, and FSHR323 showed specific binding to native, cell-presented hFSHR. Since Ylanthia® antibodies were selected to specifically recognize native FSHR, as required for a potential therapeutic antibody candidate, FSHR323 was the only antibody to detect the receptor in IHC/histochemical settings on transfected cells, and at markedly lower, physiological concentrations (ex., in Sertoli cells of human testes). The pattern of FSH323 staining noticed for ovarian, prostatic, and renal adenocarcinomas indicated that FSHR was expressed mainly in the peripheral tumor blood vessels.

CONCLUSION

Of all published IHC antibodies tested, only antibody FSHR323 proved suitable for target validation of hFSHR in an IHC setting for cancer. Our studies could not confirm the previously reported FSHR overexpression in ovarian and prostate cancer cells. Instead, specific overexpression in peripheral tumor blood vessels could be confirmed after thorough validation of the antibodies used.

Expression of serum- and glucocorticoid-regulated kinase 1 and its association with clinicopathological factors and the survival of patients with adenocarcinoma of the esophagogastric junction

While the aberrant expression and the controversial results of serum- and glucocorticoid-regulated kinase (SGK1) have been reported in a number of malignancies, the expression of SGK1 and its possible association with the progression of adenocarcinoma in the esophagogastric junction (AEG) remain to be elucidated. To the best of our knowledge, the expression and localization of SGK1 was examined for the first time in the present study in cancerous and adjacent tissue from 60 patients with AEG, and compared with 20 healthy mucosa control tissue samples. Furthermore, the association between SGK1 expression and the clinicopathological characteristics, and prognosis of patients with AEG was statistically analyzed. The expression level of SGK1 was identified to be significantly higher (P<0.0001) in the cancerous AEG tissue samples (65%) compared with that of the adjacent tissue (31.7%) and healthy control (10%) samples. Enhanced SGK1 was primarily localized in the cytoplasm and the expression level of SGK1 was associated with the differentiation (P=0.045) and lymph node metastasis (P=0.006) of AEG. Notably, increased expression of SGK1 was demonstrated to be significantly correlated with poor overall survival (P=0.027). The results of the present study revealed the expression profile of SGK1 in AEG and demonstrated that SGK1 expression in cancerous tissue is an indicator for the progression of AEG. Thus, SGK1 may be a potential molecular marker for the diagnosis, interference therapy and prognosis of AEG.

Onset and Heterogeneity of Responsiveness to FSH in Mouse Preantral Follicles in Culture

The obligatory role of follicle-stimulating hormone (FSH) in normal development and function of ovarian antral follicles is well recognized, but its function in preantral growth is less clear. The specific objective of this study was to investigate the response, in culture, to FSH of mouse preantral follicles of increasing size, focusing particularly on growth rate and gene expression. Preantral follicles were mechanically isolated from ovaries of C57BL/6 mice, 12 to 16 days postpartum, and single follicles cultured for up to 96 hours in medium alone (n = 511) or with recombinant human FSH 10 ng/mL (n = 546). Data were grouped according to initial follicle diameter in 6 strata ranging from <100 to >140 μm. Follicles of all sizes grew in the absence of FSH (P < 0.01, paired t test). All follicles grew at a faster rate (P < 0.0001) in the presence of 10 ng/mL FSH but larger follicles showed the greatest change in response to FSH. Even the smallest follicles expressed FSH receptor messenger RNA (mRNA). FSH-induced growth was inhibited by KT5720, an inhibitor of protein kinase A (PKA), implicating the PKA pathway in FSH-induced follicle growth. In response to FSH in vitro, FSH receptor mRNA (measured by quantitative polymerase chain reaction) was reduced (P < 0.01), as was Amh (P < 0.01), whereas expression of StAR (P < 0.0001) and the steroidogenic enzymes Cyp11a1 (P < 0.01) and Cyp19 (P < 0.0001) was increased. These results show heterogeneous responses to FSH according to initial follicle size, smaller follicles being less FSH dependent than larger preantral follicles. These findings strongly suggest that FSH has a physiological role in preantral follicle growth and function.

FOXL2 molecular status in adult granulosa cell tumors of the ovary: A study of primary and metastatic cases

Granulosa cell tumors (GCTs) of the ovary are uncommon neoplasms, accounting for ~5% of all malignant ovarian tumors. GCTs are a relatively homogeneous group of tumors, categorized into two distinct subtypes, juvenile GCT and adult GCT (AGCT), likely arising from a limited set of molecular events usually involving the disruption of pathways that regulate granulosa cell proliferation. In the present study, the presence of forkheadbox L2 (FOXL2) c.402C>G mutation was investigated in a series of 42 samples of primary and metastatic AGCT of the ovary. The samples consisted of 37 primary and 5 metastatic ovarian AGCTs from 37 patients. FOXL2 mutational status was evaluated using a pyrosequencing approach on 2.5-µm sections of formalin-fixed paraffin-embedded tissue. FOXL2 c.402C>G mutation was found in 33/37 (89.2%) primary AGCTs and in 4/5 (80.0%) metastases, with the molecular status of the metastases recapitulating that of the primary tumors (4 mutated cases and 1 wild-type case). Overall, FOXL2 mutation is present in the majority of primary and metastatic AGCTs, and could be used as a valid tool in the diagnosis of the disease and in cases of metastatic lesions from an unknown primary origin. Moreover the concordance of FOXL2 molecular status in primary and associated metastases suggests its early appearance and genomic stability in AGCT tumorigenesis.

Transcriptomic analysis of stage 1 versus advanced adult granulosa cell tumors

Ovarian granulosa cell tumors (GCT) are hormonally-active neoplasms characterized, in the adult-subtype, by a mutation in the FOXL2 gene (C134W). They exhibit an indolent course with an unexplained propensity for late recurrence; ~80% of patients with aggressive, advanced stage tumors die from their disease; aside from surgery, therapeutic options are limited. To identify the molecular basis of advanced stage disease we have used whole transcriptome analysis of FOXL2 C134W mutation positive adult (a)GCT to identify genes that are differentially expressed between early (stage 1) and advanced (stage 3) aGCT. Transcriptome profiles for early (n = 6) and stage 3 (n = 6) aGCT, and for the aGCT-derived KGN, cell line identified 24 genes whose expression significantly differs between the early and stage 3 aGCT. Of these, 16 were more abundantly expressed in the stage 3 aGCT and 8 were higher in the stage 1 tumors. These changes were further examined for the genes which showed the greatest fold change: the cytokine CXCL14, microfibrillar-associated protein 5, insulin-like 3 and desmin. Gene Set Enrichment Analysis identified overexpression of genes on chromosome 7p15 which includes the homeobox A gene locus. The analysis therefore identifies a small number of genes with clearly discriminate patterns of expression arguing that the clinicopathological-derived distinction of the tumor stage is robust, whilst confirming the relative homogeneity of expression for many genes across the cohort and hence of aGCT. The expression profiles do however identify several overexpressed genes in both stage 1 and/or stage 3 aGCT which warrant further study as possible therapeutic targets.

Tyrosine Kinase Inhibitors as Potential Therapeutic Agents in the Treatment of Granulosa Cell Tumors of the Ovary

Objective

Granulosa cell tumors of the ovary (GCTs) represent a specific subset of malignant ovarian tumors, of which there are 2 distinct subtypes, the juvenile and the adult form. Aside from surgery, no reliable therapeutic options currently exist for patients with GCT. This study sought to investigate the potential role of small molecule tyrosine kinase inhibitors (TKIs) as novel therapeutics in the clinical management of GCT.

Materials and Methods

Using TKI with distinct but overlapping multitargeted specificities, cellular proliferation, viability, and apoptosis were evaluated in 2 human GCT-derived cell lines, COV434 and KGN.

Results

Sunitinib, which targets the imatinib-inhibited tyrosine kinases of VEGFR, KIT, PDGFR, and FLT-3, was without effect in COV434 and KGN cell lines. Sorafenib, which has a high affinity for RAF1 and BRAF, dose dependently inhibited cellular proliferation and viability in both cell lines at concentrations equivalent to that seen in other systems. A RAF1 kinase inhibitor was without effect, suggesting that sorafenib is acting via inhibition of BRAF, or that aberrant signaling originates upstream of BRAF in the MAPK pathway. In the presence of a selective Src family inhibitor (SU6656), cell proliferation and cell viability responses dissociated; that is, although SU6656 dose dependently inhibited cell viability, it had limited effect on proliferation and apoptosis.

Conclusions

These findings implicate BRAF in the activated signaling responsible for the growth and viability of GCT and suggest that TKI already in clinical use may be a therapeutic option in the treatment of GCT.

FOXO1/3 and PTEN Depletion in Granulosa Cells Promotes Ovarian Granulosa Cell Tumor Development

The forkhead box (FOX), FOXO1 and FOXO3, transcription factors regulate multiple functions in mammalian cells. Selective inactivation of the Foxo1 and Foxo3 genes in murine ovarian granulosa cells severely impairs follicular development and apoptosis causing infertility, and as shown here, granulosa cell tumor (GCT) formation. Coordinate depletion of the tumor suppressor Pten gene in the Foxo1/3 strain enhanced the penetrance and onset of GCT formation. Immunostaining and Western blot analyses confirmed FOXO1 and phosphatase and tensin homolog (PTEN) depletion, maintenance of globin transcription factor (GATA) 4 and nuclear localization of FOXL2 and phosphorylated small mothers against decapentaplegic (SMAD) 2/3 in the tumor cells, recapitulating results we observed in human adult GCTs. Microarray and quantitative PCR analyses of mouse GCTs further confirmed expression of specific genes (Foxl2, Gata4, and Wnt4) controlling granulosa cell fate specification and proliferation, whereas others (Emx2, Nr0b1, Rspo1, and Wt1) were suppressed. Key genes (Amh, Bmp2, and Fshr) controlling follicle growth, apoptosis, and differentiation were also suppressed. Inhbb and Grem1 were selectively elevated, whereas reduction of Inha provided additional evidence that activin signaling and small mothers against decapentaplegic (SMAD) 2/3 phosphorylation impact GCT formation. Unexpectedly, markers of Sertoli/epithelial cells (SRY [sex determining region Y]-box 9/keratin 8) and alternatively activated macrophages (chitinase 3-like 3) were elevated in discrete subpopulations within the mouse GCTs, indicating that Foxo1/3/Pten depletion not only leads to GCTs but also to altered granulosa cell fate decisions and immune responses. Thus, analyses of the Foxo1/3/Pten mouse GCTs and human adult GCTs provide strong evidence that impaired functions of the FOXO1/3/PTEN pathways lead to dramatic changes in the molecular program within granulosa cells, chronic activin signaling in the presence of FOXL2 and GATA4, and tumor formation.

mTOR signaling in tumorigenesis

mTOR (the mechanistic target of rapamycin) is an atypical serine/threonine kinase involved in regulating major cellular functions including growth and proliferation. Deregulation of the mTOR signaling pathway is one of the most commonly observed pathological alterations in human cancers. To this end, oncogenic activation of the mTOR signaling pathway contributes to cancer cell growth, proliferation and survival, highlighting the potential for targeting the oncogenic mTOR pathway members as an effective anti-cancer strategy. In order to do so, a thorough understanding of the physiological roles of key mTOR signaling pathway components and upstream regulators would guide future targeted therapies. Thus, in this review, we summarize available genetic mouse models for mTORC1 and mTORC2 components, as well as characterized mTOR upstream regulators and downstream targets, and assign a potential oncogenic or tumor suppressive role for each evaluated molecule. Together, our work will not only facilitate the current understanding of mTOR biology and possible future research directions, but more importantly, provide a molecular basis for targeted therapies aiming at key oncogenic members along the mTOR signaling pathway.

Gynecologic Cancer InterGroup (GCIG) consensus review for ovarian sex cord stromal tumors

Sex cord stromal tumors (SCST) are rare cancers of the ovarian area in adults. They constitute a heterogeneous group of tumors that develop from the sex cords and the ovarian stroma. These tumors are detected typically at an early stage, and they may recur as late as 30 years after the initial treatment. Because 70% of the patients present with stage I tumors, surgery represents the most important therapeutic arm. There are no data to support any kind of postoperative adjuvant treatment for patients with stage IA or IB SCSTs, given the indolent nature of these neoplasms and the overall good prognosis. The long natural history of the disease may lead to repeated surgical procedure should a relapse occurs. Platinum-based chemotherapy is currently used for patients with advanced stage SCSTs or recurrent disease, with an overall response rate of 63% to 80%. The indolent nature of SCSTs with the tendency for late recurrence requires long-term follow-up.

Liver receptor homologue-1 expression in ovarian epithelial and granulosa cell tumours

Granulosa cell tumours of the ovary (GCT) express aromatase and produce oestrogens. The ovarian-specific aromatase promoter (pII) is regulated by members of the group 5A nuclear receptor family, SF-1 and LRH-1. Since both SF-1 and LRH-1 are implicated in proliferation and cancer, we hypothesised that alteration in the expression of either or both receptors may be associated with GCT. We therefore determined the expression of LRH-1, SF-1 and aromatase in a cohort of GCT, mucinous and serous cystadenocarcinomas, and normal ovaries. LRH-1 mRNA was present at low level in normal ovary and serous cystadenocarcinoma, but was elevated approximately 30-fold in GCT, and 8-fold in mucinous cystadenocarcinoma, compared to normal ovary. LRH-1 protein expression was confirmed in GCT by immunohistochemistry. SF-1 mRNA was significantly lower that of LRH-1 in all samples and not significantly altered in GCT, compared to normal ovary. Aromatase mRNA was present at low level in normal ovary and serous and mucinous cystadenocarcinoma, and significantly elevated (18-fold) in GCT compared to normal ovary. Despite the coordinate over-expression of both LRH-1 and aromatase in GCT versus normal ovary, their levels did not correlate in individual patients; rather, aromatase expression correlated with that of SF-1. Finally, although both LRH-1 and SF-1 activated aromatase promoter activity in transient transfection studies, gel-shift and chromatin immunoprecipitation data indicated that SF-1, but not LRH-1, bound to the aromatase promoter. We conclude that SF-1 regulates aromatase expression in GCT; over-expression of LRH-1 suggests that this receptor may be involved in the pathogenesis of GCT by mechanisms other than the regulation of aromatase. Its role in this disease therefore warrants further investigation.

Selenium-binding protein 1: its physiological function, dependence on aryl hydrocarbon receptors, and role in wasting syndrome by 2,3,7,8-tetrachlorodibenzo-p-dioxin

BACKGROUND

Selenium-binding protein 1 (Selenbp1) is suggested to play a role in tumor suppression, and may be involved in the toxicity produced by dioxin, an activator of aryl hydrocarbon receptors (AhR). However, the mechanism or likelihood is largely unknown because of the limited information available about the physiological role of Selenbp1.

METHODS

To address this issue, we generated Selenbp1-null [Selenbp1 (-/-)] mice, and examined the toxic effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in this mouse model.

RESULTS

Selenbp1 (-/-) mice exhibited only a few differences from wild-type mice in their apparent phenotypes. However, a DNA microarray experiment showed that many genes including Notch1 and Cdk1, which are known to be enhanced in ovarian carcinoma, are also increased in the ovaries of Selenbp1 (-/-) mice. Based on the different responses to TCDD between C57BL/6J and DBA/2J strains of mice, the expression of Selenbp1 is suggested to be under the control of AhR. However, wasting syndrome by TCDD occurred equally in Selenbp1 (-/-) and (+/+) mice.

CONCLUSIONS

The above pieces of evidence suggest that 1) Selenbp1 suppresses the expression of tumor-promoting genes although a reduction in Selenbp1 alone is not very serious as far as the animals are concerned; and 2) Selenbp1 induction by TCDD is neither a pre-requisite for toxicity nor a protective response for combating TCDD toxicity.

GENERAL SIGNIFICANCE

Selenbp1 (-/-) mice exhibit little difference in their apparent phenotype and responsiveness to dioxin compared with the wild-type. This may be due to the compensation of Selenbp1 function by a closely-related protein, Selenbp2.

Ovarian cancer risk is reduced by prolonged lactation: a case-control study in southern China

BACKGROUND

Ovarian cancer is an important neoplasm that is difficult to diagnose and treat; therefore, prevention is the preferable strategy. Growing evidence indicates a protective effect of breastfeeding on ovarian cancer risk.

OBJECTIVE

The objective was to investigate the association between lactation and the risk of ovarian cancer among southern Chinese women.

DESIGN

A case-control study was undertaken in Guangzhou, Guangdong Province, between August 2006 and July 2008. A validated and reliable questionnaire was used to obtain information on the months of lactation and number of children breastfed in a sample of 493 incident ovarian cancer patients and 472 hospital-based controls (mean age: 59 y). Logistic regression analyses were performed to assess the association between breastfeeding and the risk of ovarian cancer.

RESULTS

Significant inverse dose-response relations were found for both duration of lactation and the number of children breastfed. The adjusted ORs were 0.09 (95% CI: 0.04, 0.19) for women with ≥31 mo of total lactation and those with ≤10 mo of lactation and 0.38 (95% CI: 0.27, 0.55) for women with ≥3 children breastfed compared with those with one child breastfed.

CONCLUSION

Prolonged lactation is associated with a lower risk of ovarian cancer in parous Chinese women.

Reversal of paclitaxel resistance in epithelial ovarian carcinoma cells by a MUC1 aptamer-let-7i chimera

The purpose of this study was to establish tumor tissue specific delivery of let-7i miRNA to reverse paclitaxel-induced chemoresistance. A chimera that combines MUC1 aptamer and let-7i miRNA was tested in OVCAR-3 ovarian cancer cells. Results demonstrated that the chimera can specifically be delivered into OVCAR-3 cells and the released let-7i significantly sensitized the role of paclitaxel in inhibiting cell proliferation, inducing cell apoptosis, and decreasing long-term cell survival. The chimera achieved reversal of chemoresistance through downregulation of cyclin D1, cyclin D2, Dicer 1, and PGRMC1 expressions. Our study indicated that this MUC1/let-7i chimera can specifically reverse chemoresistance to paclitaxel.

A comprehensive curated resource for follicle stimulating hormone signaling

BACKGROUND

Follicle stimulating hormone (FSH) is an important hormone responsible for growth, maturation and function of the human reproductive system. FSH regulates the synthesis of steroid hormones such as estrogen and progesterone, proliferation and maturation of follicles in the ovary and spermatogenesis in the testes. FSH is a glycoprotein heterodimer that binds and acts through the FSH receptor, a G-protein coupled receptor. Although online pathway repositories provide information about G-protein coupled receptor mediated signal transduction, the signaling events initiated specifically by FSH are not cataloged in any public database in a detailed fashion.

FINDINGS

We performed comprehensive curation of the published literature to identify the components of FSH signaling pathway and the molecular interactions that occur upon FSH receptor activation. Our effort yielded 64 reactions comprising 35 enzyme-substrate reactions, 11 molecular association events, 11 activation events and 7 protein translocation events that occur in response to FSH receptor activation. We also cataloged 265 genes, which were differentially expressed upon FSH stimulation in normal human reproductive tissues.

CONCLUSIONS

We anticipate that the information provided in this resource will provide better insights into the physiological role of FSH in reproductive biology, its signaling mediators and aid in further research in this area. The curated FSH pathway data is freely available through NetPath (http://www.netpath.org), a pathway resource developed previously by our group.

SGK1-dependent salt appetite in pregnant mice

AIM

Pregnancy is typically paralleled by substantial increase in maternal extracellular fluid volume, requiring net accumulation of water and NaCl. The positive water and salt balance is accomplished at least in part by increased uptake of salt secondary to enhanced salt appetite. Little is known about the underlying cellular mechanisms. Stimulation of salt appetite by mineralocorticoids, however, is known to be dependent on the serum- and glucocorticoid-inducible kinase SGK1.

METHODS

To test for a role of SGK1 in the stimulation of salt appetite during pregnancy, fluid intake was recorded in pregnant SGK1 knockout mice (sgk1(-/-) ) and their wild type littermates (sgk1(+/+) ). The mice were offered two bottles, one with plain water and the other with isotonic saline.

RESULTS

In early pregnancy, i.e. up to 10 days prior to parturition, the sgk1(+/+) mice displayed a significant preference for saline, whereas the sgk1(-/-) mice preferred water. Accordingly, the water intake was significantly smaller and saline intake was significantly larger in sgk1(+/+) mice than in sgk1(-/-) mice and the preference for water was significantly stronger in sgk1(-/-) mice than in sgk1(+/+) mice. Plasma aldosterone levels were higher in sgk1(-/-) mice than in sgk1(+/+) mice, a difference contrasting the enhanced salt appetite of sgk1(+/+) mice.

CONCLUSIONS

SGK1 participates in the stimulation of salt appetite during pregnancy.

COX-2 expression in nonepithelial ovarian malignancies

The aim of the study was to assess the expression of cyclooxygenases (COX)-2 in nonepithelial ovarian malignancies.COX-2 immunohistochemical staining was performed on newly prepared deparaffinized slides from formalin-fixed, paraffin-embedded archival tissue blocks of unselected nonepithelial ovarian malignancies diagnosed between January 1993 and October 2009 after reconfirmation of the diagnosis. Staining was assessed according to intensity of staining and the proportion of stained cells. Staining of more than 10% of the cells was considered positive.During the study period, 26 histologically proven nonepithelial ovarian malignancies were diagnosed. Of them, 16 were granulosa cell tumors and 10 were germ cell tumors (4 dysgerminomas and 6 immature teratomas). Five (31.2%) granulosa cell tumors had positive immunohistochemical COX-2 staining. Positive staining was observed only in 1 immature teratoma and in none of the dysgerminomas.Our data seem to indicate that COX-2 expression by immunohistochemical methods is not frequent in nonepithelial ovarian malignancies.

Minireview: roles of the forkhead transcription factor FOXL2 in granulosa cell biology and pathology

The forkhead transcription factor (FOXL2) is an essential transcription factor in the ovary. It is important in ovarian development and a key factor in female sex determination. In addition, FOXL2 plays a significant role in the postnatal ovary and follicle maintenance. The diverse transcriptional activities of FOXL2 are likely attributable to posttranslational modifications and binding to other key proteins involved in granulosa cell function. Mutations of FOXL2 lead to disorders of ovarian function ranging from premature follicle depletion and ovarian failure to unregulated granulosa cell proliferation leading to tumor formation. Thus, FOXL2 is a key regulator of granulosa cell function and a master transcription factor in these cells.

Second AKT: the rise of SGK in cancer signalling

The serum and glucocorticoid kinase (SGK) family of serine/threonine kinases consists of three isoforms, SGK-1, SGK-2 and SGK-3. This family of kinases is highly homologous to the AKT kinase family, sharing similar upstream activators and downstream targets. SGKs have been implicated in the regulation of cell growth, proliferation, survival and migration: cellular processes that are dysregulated in cancer. Furthermore, SGKs lie downstream of phosphoinositide-3-kinase (PI3Kinase) signalling and interact at various levels with RAS/RAF/ERK signalling, two pathways that are involved in promoting tumorigenesis. Recent evidence suggests that mutant PI3Kinase can induce tumorigenesis through an AKT-independent but SGK3-dependent mechanism, thus implicating SGKs as potential players in malignant transformation. Here, we will review the current state of knowledge on the regulation of the SGKs and their role in normal cell physiology and transformation with a particular focus on SGK3.

Down-regulation of serum/glucocorticoid regulated kinase 1 in colorectal tumours is largely independent of promoter hypermethylation

Background

We have previously shown that serum/glucocorticoid regulated kinase 1 (SGK1) is down-regulated in colorectal cancers (CRC) with respect to normal tissue. As hyper-methylation of promoter regions is a well-known mechanism of gene silencing in cancer, we tested whether the SGK1 promoter region was methylated in colonic tumour samples.

Methodology/Principal Findings

We investigated the methylation profile of the two CpG islands present in the promoter region of SGK1 in a panel of 5 colorectal cancer cell lines by sequencing clones of bisulphite-treated DNA samples. We further confirmed our findings in a panel of 10 normal and 10 tumour colonic tissue samples of human origin. We observed CpG methylation only in the smaller and more distal CpG island in the promoter region of SGK1 in both normal and tumour samples of colonic origin. We further identified a single nucleotide polymorphism (SNP, rs1743963) which affects methylation of the corresponding CpG.

Conclusions/Significance

Our results show that even though partial methylation of the promoter region of SGK1 is present, this does not account for the different expression levels seen between normal and tumour tissue.

The FOXL2 C134W mutation is characteristic of adult granulosa cell tumors of the ovary

Granulosa cell tumors of the ovary represent ∼5% of malignant ovarian cancers. It has recently been reported that 95-97% of adult granulosa cell tumors carry a unique somatic mutation in the FOXL2 gene. We undertook this study to verify the presence of the FOXL2 Cys134Trp mutation in two geographically independent cohorts of granulosa cell tumors and to examine the expression pattern of FOXL2 in these tumors. A total of 56 tumors with the histological diagnosis of adult granulosa cell tumor from two centers, Melbourne and Helsinki, were examined for the presence of the mutation using direct sequence analysis. Two granulosa cell tumor-derived cell lines, COV434 and KGN, three juvenile granulosa cell tumors and control tissues were also examined. The expression of the FOXL2 gene was determined using quantitative RT-PCR and/or immunohistochemistry. We found that 52 of the 56 adult granulosa cell tumors harbor the mutation, of which three were hemi/homozygous. Of the four cases with wild-type FOXL2 sequence, reappraisal suggests that three may have been misclassified at primary diagnosis. The KGN cells were heterozygous for the mutation, whereas the COV434 cells had a wild-type FOXL2 genotype. The expression levels of FOXL2 were similar across the adult granulosa cell tumors and the normal ovary controls; one mutation-negative granulosa cell tumor had high FOXL2 mRNA levels, whereas the COV434 cells and two of the three juvenile granulosa cell tumors lacked the expression of FOXL2. Our data provide confirmation of the frequent presence of the FOXL2 C134W mutation in adult granulosa cell tumors and demonstrate that the mutation is not associated with altered FOXL2 expression. The mutation analysis may be a useful tool to differentiate particularly between cell-rich diffuse granulosa cell tumors and mitotically active sex cord-stromal tumors. This unique FOXL2 mutation appears to be characteristic of adult granulosa cell tumors.

Defective gonadotropin-dependent ovarian folliculogenesis and granulosa cell gene expression in inhibin-deficient mice

Inhibin-α knockout (Inha-/-) female mice develop sex cord-stromal ovarian cancer with complete penetrance and previous studies demonstrate that the pituitary gonadotropins (FSH and LH) are influential modifiers of granulosa cell tumor development and progression in inhibin-deficient females. Recent studies have demonstrated that Inha-/- ovarian follicles develop precociously to the early antral stage in prepubertal mice without any increase in serum FSH. These studies suggest that in the absence of inhibins, granulosa cells differentiate abnormally and thus at sexual maturity may undergo an abnormal response to gonadotropin signaling contributing to tumor development. To test this hypothesis, we stimulated immature wild-type and Inha-/- female mice with gonadotropin analogs prior to tumor formation and subsequently examined gonadotropin-induced ovarian follicle development as well as preovulatory and human chorionic gonadotropin-induced gene expression changes in granulosa cells. We find that at 3 wk of age, inhibin-deficient ovaries do not show further antral development or undergo cumulus expansion. In addition, there are widespread alterations in the transcriptome of gonadotropin-treated Inha-/- granulosa cells, with significant changes in genes involved in extracellular matrix and cell-cell communication. These data indicate the gonadotropins initiate an improper program of cell differentiation prior to tumor formation in the absence of inhibins.

Relative resistance of SGK1 knockout mice against chemical carcinogenesis

The serum and glucocorticoid inducible kinase SGK1 was originally cloned from mammary tumor cells. SGK1 was found to be up-regulated in a variety of tumors, but down-regulated in several distinct tumors. Thus, evidence for a role of SGK1 in tumor growth remained conflicting. According to in vitro observations, SGK1 is up-regulated by the oncogene beta-catenin and negatively regulates the proapoptotic transcription factor FOXO3a, which in turn stimulates transcription of the Bcl2-interacting mediator BIM. This study aimed to define the role of SGK1 in colon carcinoma in vivo. SGK1 knockout mice (sgk1(-/-)) and their wild type littermates (sgk1(+/+)) were subjected to chemical cancerogenesis (intraperitoneal injection of 20 mg/kg 1,2-dimethylhydrazine followed by three cycles of 30 g/L synthetic dextran sulfate sodium for 7 days). Moreover, SGK1 was silenced in HEK293 cells. FOXO3a and BIM protein abundance was determined by Western blotting and immunohistochemistry. Following chemical cancerogenesis, sgk1(-/-)mice developed significantly less colonic tumors than sgk1(+/+)mice. According to Western blotting and immunohistochemistry, SGK1 deficiency enhanced the expression of FOXO3a and BIM both, in vitro and in vivo. SGK1 deficiency counteracts the development of colonic tumors, an effect at least in part due to up-regulation of FOXO3a and BIM.

The new molecular biology of granulosa cell tumors of the ovary

Granulosa cell tumors (GCTs) of the ovary belong to the group of ovarian sex-cord stromal tumors and represent 5 to 10% of ovarian malignancies. GCTs exhibit several morphological, biochemical and hormonal features of normal proliferating pre-ovulatory granulosa cells, such as estrogen biosynthesis. Prognostic factors of this condition are lacking, and alternative treatment options to preserve future fertility are needed. Several groups have shown that two genetic factors implicated in GCTs are of particular interest. The gsp oncogene is a constitutive activating mutation of the prognosis of the tumor. FOXL2 is a transcription factor gene involved in ovarian development and function, whose expression is reduced and which is mutated in the majority of GCTs. FOXL2 appears to play a major role in cell cycle regulation. These recent findings open new pathophysiological insights into GCT development as well as revisitation of granulosa cell and ovarian function.

Expression status and mutational analysis of the PTEN and P13K subunit genes in ovarian granulosa cell tumors

Granulosa cell tumors (GCT) are a unique subset of ovarian tumors which have a molecular phenotype resembling that of follicle stimulating hormone (FSH)-stimulated pre-ovulatory granulosa cells. FSH acts via its receptor to stimulate signaling pathways including the phosphatidylinositol 3-kinase (PI3K)-AKT pathway. Activation of this pathway occurs in solid tumors, including ovarian epithelial tumors, through mutation of the PI3K subunit genes or inactivation of the tumor suppressor, PTEN. Activation of this pathway would be predicted to be tumorigenic in granulosa cells.Expression of the 2 PI3K subunit genes, PIK3CA, which encodes the catalytic subunit, and PIK3R1, which encodes the regulatory subunit, together with the PTEN gene was determined in a panel of GCT, 2 human GCT-derived cell lines, COV434 and KGN, and normal ovary. Direct sequence analysis was used to screen for mutations. Expression of all 3genes was observed in the GCT without evidence of overexpression for the PI3K subunit genes or loss of expression for PTEN. Sequence analysis of amplicons spanning exons 9and 20, in which greater than 75% of mutations occur in the PIK3CA gene did not identify any missense mutations. Similarly, the previously reported deletions in exons 12 and 13 of the PIK3R1 were not found in the GCT. Three amplicons spanning the entire coding sequence of the PTEN gene were sequenced; neither deletions nor mutations were identified.These findings suggest that activation of PI3K signaling through PI3K/PTEN mutation or altered expression, in contrast to many other types of solid tumor, is not associated with GCT.

Hormones as biomarkers: practical guide to utilizing luminex technologies for biomarker research

Hormones are chemical messengers produced in one part of the body and released into the blood to trigger or regulate particular functions of the body in another part. Hormone actions vary widely, but can include stimulation or inhibition of growth, induction or suppression of apoptosis, activation or inhibition of the immune system, regulating metabolism, and preparation for a new activity or phase of life. There is a growing interest in the role that hormones may play in the development and progression of various cancers. Recent research suggests that hormone levels may explain differences in risk for some of the most commonly diagnosed cancers, including breast, ovarian, and others; however, additional studies utilizing novel hormone measurement technologies are needed to investigate the roles of common hormones in cancer. Increasing our understanding of the role of hormones and other biomarkers in the etiology and the course of different cancers has a great potential to facilitate the development of new treatment modalities. This chapter provides an overview on multiplexing xMAP technology by Luminex (Austin, TX) that can be used for simultaneous analysis of several biologic markers, e.g., hormones. The xMAP immunoassay technology combines the principle of a sandwich ELISA with the fluorescent-bead-based technology allowing individual and multiplex analysis of up to 100 different analytes in a single microtiter well. Serum assay described in the methods section is performed in 96-well microplate format according to the protocol provided by LINCO Research, Inc. (St. Louis, MO). Human Pituitary LINCOplex Kit is utilized for simultaneous quantification of six pituitary hormones in serum, plasma, tissue lysate, and culture supernatant samples: Prolactin, FSH, LH, TSH, GH, and ACTH.

Overexpression of follicle-stimulating hormone receptor facilitates the development of ovarian epithelial cancer

We previously showed that the expressing level of FSH receptor (FSHR) increased from ovarian epithelial inclusions (OEIs) to benign ovarian epithelial tumors (OETs) and to borderline OETs, whereas FSHR levels decreased with an increase in carcinoma grade. The aim of this study was to investigate the role of FSHR in OET development. MCV152 cells with FSHR overexpression showed an increased cellular proliferation and invasive capacity, which was associated with reduced levels of prohibitin and RII-beta expression and increased levels of HER-2/neu, c-Myc, and EGFR expression. Overexpression of FSHR may be associated with an elevated level of OET cell proliferation via an enhanced activity of potential oncogenic pathways. Therefore, the findings in this study suggest that overexpression of FSHR may play a role in OET development.

SGK1-sensitive renal tubular glucose reabsorption in diabetes

The hyperglycemia of diabetes mellitus increases the filtered glucose load beyond the maximal tubular transport rate and thus leads to glucosuria. Sustained hyperglycemia, however, may gradually increase the maximal renal tubular transport rate and thereby blunt the increase of urinary glucose excretion. The mechanisms accounting for the increase of renal tubular glucose transport have remained ill-defined. A candidate is the serum- and glucocorticoid-inducible kinase SGK1. The kinase has been shown to stimulate Na(+)-coupled glucose transport in vitro and mediate the stimulation of electrogenic intestinal glucose transport by glucocorticoids in vivo. SGK1 expression is confined to glomerula and distal nephron in intact kidneys but may extend to the proximal tubule in diabetic nephropathy. To explore whether SGK1 modifies glucose transport in diabetic kidneys, Akita mice (akita(+/-)), which develop spontaneous diabetes, have been crossbred with gene-targeted mice lacking SGK1 on one allele (sgk1(+/-)) to eventually generate either akita(+/-)/sgk1(-/-) or akita(+/-)/sgk1(+/+) mice. Both akita(+/-)/sgk1(-/-) and akita(+/-)/sgk1(+/+) mice developed profound hyperglycemia (>20 mM) within approximately 6 wk. Body weight and plasma glucose concentrations were not significantly different between these two genotypes. However, urinary excretion of glucose and urinary excretion of fluid, Na(+), and K(+), as well as plasma aldosterone concentrations, were significantly higher in akita(+/-)/sgk1(-/-) than in akita(+/-)/sgk1(+/+) mice. Studies in isolated perfused proximal tubules revealed that the electrogenic glucose transport was significantly lower in akita(+/-)/sgk1(-/-) than in akita(+/-)/sgk1(+/+) mice. The data provide the first evidence that SGK1 participates in the stimulation of renal tubular glucose transport in diabetic kidneys.

[Juvenile granulosa-cell tumor: clinical and molecular expression]

Ovarian sex cord-stromal tumors are rare tumors that originate from the nongerminal cells of ovary. Two decades ago, the identification of juvenile granulosa-cell tumors (GCT), as a specific entity inside this group, allowed a better treatment of these tumors in children. However, little data have been reported on the natural course of the disease and reliable prognostic factors have not been yet defined. We here review the clinical and genetics aspects of granulosa tumors, based on a series of 40 children. This national collaborative study involved the French Society of Children Cancer and eight clinical departments of pediatric endocrinology. We found that early diagnosis of a tumor, revealed by clinical signs of hyperoestrogeny, is an important prognostic factor. The pathophysiology of these tumors is still debatable and several cellular- and molecular-abnormal signals could be implicated in their development. The role of growth factors and oncogenes through the signaling pathway of MAP kinase is still discussed. According to our data, FSH signaling-transduction pathway, such as a constitutionally activated Galphas, could also be implicated in the induction of granulosa cell proliferation and seems to modulate the invasiveness of the tumor. Last, we have described a low-expression pattern or an extinction of an ovarian-determination gene, FOXL2, which is related to a worse prognosis of this tumor.

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.

Differential regulation of serum- and glucocorticoid-inducible kinase 1 (SGK1) splice variants based on alternative initiation of transcription

The serum- and glucocorticoid-inducible kinase 1 (SGK1) is a key-regulator of transport, cell volume and cell survival. SGK1 transcription is under genomic control of a wide variety of hormones and cell stressors. Little is known, however, about sequence variation in SGK1 transcripts. Thus, we took an in silico approach to determine sequence variations in the N-terminal region of SGK1, which is considered particularly important for subcellular SGK1 localization. Expressed Sequence Tag analysis revealed two novel phylogenetically highly conserved SGK1 mRNAs with different promoter sites based on alternative initiation of transcription at -2981, -850 upstream of the transcription initiation site (+1) of the reference mRNA. RT-PCR in various human cell lines and tissues confirmed the expression of the 3 alternative splice variants, which differed exclusively in their first exons. The two novel variants were devoid of the localization and degradation signal with otherwise unchanged and intact open reading frames. Spatial distribution of transcription factor binding sites among the three promoter sites indicated common responsiveness to glucocorticoids but different responsiveness to hypoxia and cellular differentiation. Differential expression under those conditions was confirmed for all variants in cultured myoblasts and myotubes. p53 and ETF-1 binding sites were overrepresented at the promoter site of the reference sequence variant SGK1(+1). Transcript levels were 4.1-fold [SGK1(+1)] and 3.1-fold [SGK1(-850)] higher in renal clear cell carcinoma than in remote tissue. The transcript levels were 42-fold [SGK1(+1)], 26-fold [SGK1(-850)] and 17-fold [SGK1(-2981)] higher in highly malignant human glioma cells than in non-neoplastic brain tissue. SGK1 transcript levels were differentially increased by differentiation or hypoxia (treatment with CoCl(2)). In conclusion, the present observations disclose the transcription of three distinct SGK1 splice variants, which are all markedly upregulated in tumor tissue but differentially upregulated following differentiation or hypoxia.

Expression, mutational analysis and in vitro response of imatinib mesylate and nilotinib target genes in ovarian granulosa cell tumors

OBJECTIVES

Granulosa cell tumors of the ovary (GCT) represent approximately 5% of malignant ovarian tumors. Surgery remains the primary modality of therapy and treatment options for advanced disease are limited. The molecular pathogenesis of GCT is not known but is likely to involve activation of tyrosine kinase-mediated cell signaling pathways. A recent case report of a patient with advanced recurrent GCT responding to the tyrosine kinase inhibitor, imatinib mesylate prompted us to explore a role for these therapies in GCT.

METHODS

The expression of the imatinib-sensitive tyrosine kinases, c-kit, c-Abl, PDGFR-alpha and PDGFR-beta, was determined using RT-PCR in a panel of GCT. Activating mutations of c-kit and PDGFR-alpha were also sought. The functional response was examined in two human-derived GCT cell lines.

RESULTS

All four kinases were expressed but at levels lower than those observed in pre-menopausal ovarian samples. Mutations in c-kit and PDGFR-alpha were not found. Both cell lines responded to imatinib and to the second generation, tyrosine kinase inhibitor, nilotinib, with dose-dependent decreases in cell proliferation and viability. These responses paralleled the imatinib-sensitive, K562 cell line but at approximately 240- and approximately 1000-fold higher concentrations of imatinib and nilotinib, respectively.

CONCLUSIONS

Our study suggests that human GCT, in general, are unlikely to respond to imatinib or nilotinib therapy. The response of the cell lines at high concentrations implies an "off-target" effect, which suggests that a tyrosine kinase inhibitor, of appropriate specificity, may represent a therapeutic option in GCT.

Expression of serum and glucocorticoid-inducible kinase1 in diabetic rats and its modulation by fluvastatin

The expression of serum and glucocorticoid-induced protein kinase in the renal cortex of diabetic rats was examined, and the function of signal transduction mediated by SGK1 in diabetic nephropathy and its modulatiqn by fluvastatin were also investigated. 24 male Wistar rats were randomly divided into normal control group (n = 8), diabetic nephropathy group (n = 8) and fluvastatin-treated diabetic nephropathy group (15 mg/kg/d, n = 8). The metabolic parameters were measured at the 8th week. The expression of transforming growth factor beta1 (TGF-beta1) and fibronectin (FN) was immunohistochemically examined. The expression of SGK1 was detected by RT-PCR and Western blot, and CTGF mRNA was assessed by RT-PCR. As compared to DN, blood glucose, 24-h urinary protein, Cer and kidney weight index were all decreased and the weight was increased obviously in group F. At the same time, mesangial cells and extracellular matrix proliferation were relieved significantly. The levels of cortex SGK1 mRNA and protein were up-regulated, and both TGF-beta1 and FN were down-regulated by fluvastatin. The mRNA of SGK1 was positively correlated with the CTGF, TGF-beta1 and FN. SGK1 expression is markedly up-regulated in the renal cortex of DN group and plays an important role in the development and progress of diabetic nephropathy by means of signal transduction. Fluvastatin suppressed the increased SGK1mRNA expression in renal cortex and postponed the development of diabetic nephropathy.

Gonadotropins and ovarian cancer

Ovarian epithelial cancer (OEC) accounts for 90% of all ovarian cancers and is the leading cause of death from gynecological cancers in North America and Europe. Despite its clinical significance, the factors that regulate the development and progression of ovarian cancer are among the least understood of all major human malignancies. The two gonadotropins, FSH and LH, are key regulators of ovarian cell functions, and the potential role of gonadotropins in the pathogenesis of ovarian cancer is suggested. Ovarian carcinomas have been found to express specific receptors for gonadotropins. The presence of gonadotropins in ovarian tumor fluid suggests the importance of these factors in the transformation and progression of ovarian cancers as well as being prognostic indicators. Functionally, there is evidence showing a direct action of gonadotropins on ovarian tumor cell growth. This review summarizes the key findings and recent advances in our understanding of these peptide hormones in ovarian cancer development and progression and their role in potential future cancer therapy. We will first discuss the supporting evidence and controversies in the "gonadotropin theory" and the use of animal models for exploring the involvement of gonadotropins in the etiology of ovarian cancer. The role of gonadotropins in regulating the proliferation, survival, and metastasis of OEC is next summarized. Relevant data from ovarian surface epithelium, which is widely believed to be the precursor of OEC, are also described. Finally, we will discuss the clinical applications of gonadotropins in ovarian cancer and the recent progress in drug development.

Insulin-like growth factor, insulin-like growth factor-binding protein-4, and pregnancy-associated plasma protein-A gene expression in human granulosa cell tumors

The insulin-like growth factor (IGF) system plays an important role in folliculogenesis. It is also thought to contribute to the pathogenesis of many cancers, including those of the ovarian epithelium. In the human follicle, the predominant IGF is IGF-II and its actions are modulated by insulin-like growth factor-binding protein-4 (IGFBP-4), the IGFBP-4 protease, and the pregnancy-associated plasma protein-A (PAPP-A). These peptide components are synthesized by the granulosa cells of the developing follicle. The aim of this study was to characterize the expression of these components of the IGF system in granulosa cell tumors (GCT) of the ovary. IGF-I, IGF-II, IGFBP-4, and PAPP-A gene expression was determined in a panel of GCT and compared to the levels in normal ovary and in epithelial ovarian tumors. Although both the IGF-I and IGF-II genes were expressed in the GCT, the levels were lower than in the other tissue groups. IGFBP-4 expression was also low in the GCT, whereas PAPP-A gene expression was highest in the GCT. These findings were unexpected given the prominent role this signaling system plays in normal granulosa cells. In conclusion, these observations suggest that the IGF system may have a limited role in the pathogenesis of GCT with PAPP-A subserving a function other than IGFBP-4 proteolysis.

Molecular characterization of sarcomatous change in a granulosa cell tumor

Sarcomatous transformation of a granulosa cell tumor (GCT) is a rare event. We describe the development of a rapidly progressive sarcomatous change in a woman who had initially presented with a classical GCT. A first recurrence occurred 23 months after the initial diagnosis when she was treated with external beam radiotherapy to her pelvis. A second recurrence 76 months following her initial surgery was consistent with a GCT. At 92 months, she presented with a further recurrence, outside of the radiotherapy field. This last recurrence had a different histologic appearance with features of sarcomatous change. Molecular analysis, using both reverse transcription-polymerase chain reaction and complementary DNA microarrays, has been used to analyze tissue obtained before and after the observed change in the tumor. The data show that GCT-specific genes, such as inhibin alpha, estrogen receptor, and follicle-stimulating hormone receptor, have been downregulated in the sarcomatous change. Significant upregulation of genes associated with an inflammatory response was also noted in the sarcoma, and this was consistent with the presence of a marked inflammatory infiltrate seen on histopathology. This study represents the novel application of microarray technology and demonstrates the unexpected finding of expression of the fibroblast activation protein gene in normal ovary. Although tumors such as this may be targets for the novel fibroblast activating protein-directed chemotherapeutic monoclonal antibody sibrotuzumab, the finding of expression in the normal ovary suggests the need for caution.

Ovarian granulosa cell survival and proliferation requires the gonad-selective TFIID subunit TAF4b

Oocyte development in the mammalian ovary requires productive interactions with somatic granulosa cells of the ovarian follicle. Proliferating granulosa cells support the progression of follicular growth and maturation, multiplying dramatically as it unfolds. The cell cycle recruitment of granulosa cells is regulated at least in part by hormones such as follicle-stimulating hormone (FSH) and estrogen. Follicles recruited into the growth phase following formation of multiple layers of granulosa cells have two major fates: either to continue proliferation followed by differentiation, or to die by programmed cell death, or atresia. While many of the signaling pathways orchestrating ovarian follicle development are known, the downstream transcriptional regulators that integrate such signals in the mammalian ovary remain to be defined. Recent experiments in diverse organisms have revealed multiple instances of gonad-selective components of the basal transcriptional machinery. One such protein, TAF4b, is a gonadal-enriched coactivator subunit of the TFIID complex required for normal female fertility in the mouse. To determine the etiology of female infertility of the TAF4b-deficient mice, we have determined multiple functions of TAF4b during postnatal ovarian follicle development. Here we demonstrate that the TAF4b protein is expressed in the granulosa cell compartment of the mammalian ovarian follicle. Furthermore, TAF4b-deficient mouse ovaries contain reduced numbers of primordial as well as growing follicles and a concomitant increased proportion of apoptotic follicles in comparison to wild type counterparts. Importantly, TAF4b-null follicles are largely resistant to induction of proliferation in response to multiple hormonal stimuli including estrogen and FSH and demonstrate compromised granulosa cell survival. Together, these data suggest that TAF4b integrates a program of granulosa cell gene expression required for normal ovarian follicle survival and proliferation in response to diverse ovarian signaling events.