Steroid release from two human epithelial ovarian tumors: evidence for an intrinsic production in vitro

High prevalence of atypical hyperplasia in the endometrium of patients with epithelial ovarian cancer

OBJECTIVES

The aim of the present study is to determine the prevalence of endometrial premalignancies in women diagnosed with epithelial ovarian cancer (EOC).

METHODS

Endometrial and ovarian specimens of 186 patients with EOC were retrospectively selected using the nationwide pathology network and registry, and sections were comprehensively reviewed: 136 (73%) serous, 19 (10%) endometrioid, 15 (8%) mucinous, seven (4%) clear cell, and nine (5%) undifferentiated. Immunohistochemical phenotypes were compared for patients with serous EOC with concurrent endometrial pathology.

RESULTS

In 31%, endometrial (pre)malignancy was found: carcinoma in 3%, endometrial intraepithelial carcinoma (EIC) in 4%, and atypical hyperplasia in 24%. Atypical hyperplasia was found in 47% of endometrioid EOCs but in 7% to 33% of other subtypes. Body mass index was higher concurrent to atypical hyperplasia (P=.001). Serous EOC and EIC immunophenotypes were comparable, whereas atypical hyperplasia was expressed differently.

CONCLUSIONS

Apart from synchronous endometrial carcinoma, endometrial premalignancies should be taken into account when determining optimal treatment for women diagnosed with EOC.

Immunolocalization of nuclear transcription factors, DAX-1 and Ad4BP/SF-1, in human common epithelial ovarian tumors: correlations with StAR and steroidogenic enzymes in epithelial ovarian carcinoma

Intratumoral steroidogenesis is considered to play important roles in the biologic behavior of common epithelial ovarian carcinoma. Recent studies have demonstrated the important roles of Ad4BP/SF-1 and DAX-1 in regulation of steroidogenesis. In this study, we evaluated DAX-1, Ad4BP/SF-1, StAR, and steroidogenic enzyme expressions and their correlations in epithelial ovarian carcinomas to evaluate the possible roles of these factors in regulation of intratumoral steroid metabolism and/or production. Immunolocalization of DAX-1, Ad4BP/SF-1, StAR, and steroidogenic enzymes were examined in 90 epithelial ovarian carcinomas. mRNA expression of these proteins was evaluated using real-time polymerase chain reaction (PCR) in 23 cases for further characterization. DAX-1 and Ad4BP/SF-1 immunoreactivity was detected predominately in the nuclei of tumor cells, whereas that of StAR and steroidogenic enzymes was present in the cytoplasm. We detected a significant positive correlation between StAR and steroidogenic enzymes immunoreactivity and Ad4BP/SF-1 and statistically inversed correlation with DAX-1. A positive statistical correlation was detected between intratumoral stromal Ad4BP/SF-1 immunoreactivity and clinicopathologic parameters of carcinoma patients. Results of real-time PCR analysis were correlated with those of immunohistochemical studies. The status of intratumoral DAX-1, Ad4BP/SF-1, and StAR and steroidogenic enzymes in epithelial cells and intratumoral stromal cells of epithelial ovarian carcinoma may contribute in the progression and/or aggressiveness of these tumors.

StAR and progesterone producing enzymes (3beta-hydroxysteroid dehydrogenase and cholesterol side-chain cleavage cytochromes P450) in human epithelial ovarian carcinoma: Immunohistochemical and real-time PCR studies

Steroidogenic acute regulatory protein (StAR), P450 side-chain cleavage enzyme (P450scc) and 3 beta-hydroxysteroid dehydrogenase enzyme (3beta-HSD) are all involved in the transport of cholesterol and production of progesterone. In situ production of sex steroids including progesterone have been considered to play important roles in pathogenesis and/or development of common epithelial ovarian carcinomas. In this study, StAR, P450scc, and 3beta-HSD were immunolocalized in 100 cases of ovarian carcinoma and results were then correlated with clinicopathological and prognostic parameters of individual patients including status of progesterone receptor (PR) in tumor cells. Results of immunohistochemistry were further characterized by real-time PCR analysis in 20 cases of epithelial ovarian carcinomas in which frozen tissues were available for examination. StAR, P450scc, and 3beta-HSD immunoreactivity was detected predominately in the cytoplasm of carcinoma cells. Results of real-time PCR analysis were correlated with those of immunohistochemical studies. StAR, P450scc, and 3beta-HSD H scores demonstrated significant inversed statistical correlation with FIGO stage, residual size of the tumor, and Ki67 LI. A positive statistically significant correlation was detected between StAR H score and PR-B LI. Multivariate statistical analysis demonstrated that the status of intratumoral StAR, FIGO stage, and residual tumor size all turned out to be independent prognostic factors for the clinical outcome of the patient. The presence of StAR, a cholesterol transporter for steroidogenesis in human epithelial ovarian carcinoma, may reflect the ability of these tumors to produce progesterone in situ that could influence biological behavior of these tumors, especially through progesterone dependent inhibition of tumor cell proliferation.

Insertional mutagenesis of the adeno-associated virus type 2 (AAV2) capsid gene and generation of AAV2 vectors targeted to alternative cell-surface receptors

Recombinant adeno-associated virus (AAV) vectors are of interest in the context of gene therapy because of their ability to mediate efficient transfer and stable expression of therapeutic genes in a wide variety of tissues. However, AAV-mediated gene delivery to specific cell populations is often precluded by the widespread distribution of heparan sulfate proteoglycan (HSPG), the primary cellular receptor for the virus. Conversely, an increasing number of cell types are being identified that do not express HSPG and are therefore poor targets for AAV-mediated gene transfer. To address these issues, we have developed strategies to physically modify AAV vectors and allow efficient, HSPG-independent, receptor-targeted infection. We began by generating a series of 38 virus capsid mutants containing peptide insertions at 25 unique sites within the AAV capsid protein. The mutant viruses were characterized on the basis of their phenotypes and grouped into three classes: class I mutants (4 of 38) did not assemble particles; class II mutants (14 of 38) assembled noninfectious particles; and class III mutants (20 of 38) assembled fully infectious particles. We examined the HSPG-binding characteristics of the class II mutants and showed that a defect in receptor binding was a common reason for their lack of infectivity. The display of foreign peptide epitopes on the surface of the mutant AAV particles was found to be highly dependent on the inclusion of appropriate scaffolding sequences. Optimal scaffolding sequences and five preferred sites for the insertion of targeting peptide epitopes were identified. These sites are located within each of the three AAV capsid proteins, and thus display inserted epitopes 3, 6, or 60 times per vector particle. Modified AAV vectors displaying a 15-amino acid peptide, which binds to the human luteinizing hormone receptor (LH-R), were generated and assessed for their ability to target gene delivery to receptor-bearing cell lines. Titers of these mutant vectors were essentially the same as wild-type vector. The LH-R-targeted vector was able to transduce ovarian cancer cells (OVCAR-3) in an HSPG-independent manner. Furthermore, transduction was shown to proceed via the LH-R and therefore treatment of OVCAR-3 cells with progesterone, to increase LH-R expression, accordingly increased LH mutant-mediated gene transfer. This technology may have a significant impact on the use of AAV vectors for human gene therapy.

Production of steroids by human ovarian surface epithelial cells in culture: possible role of progesterone as growth inhibitor

OBJECTIVE

The purpose was to investigate whether normal ovarian surface epithelial cells, harvested from premenopausal and postmenopausal women, are capable of steroid production, and to evaluate effects of estradiol and progesterone on growth regulation of such cells.

METHODS

Ovarian surface epithelial cells were obtained by brushing of the ovarian surface of 9 premenopausal and 10 postmenopausal women undergoing surgery for benign gynecological diseases. The conditioned media after culture, with and without addition of FSH and LH, were analyzed for estradiol and progesterone. The proliferative effects of the steroids were analyzed using two different culture models, nonconfluent cells and confluent cells, and two different detection methods, [(3)H]thymidine incorporation and a colorimetric method assaying cell number.

RESULTS

The normal ovarian surface epithelial cells were found to secrete both estradiol and progesterone, a production that was not regulated by FSH or LH. Addition of steroids to the cultured cells did not induce any overall significant growth effects. However, progesterone significantly inhibited the growth of ovarian surface epithelial cells from three of the patients. Enhanced thymidine incorporation was observed in the presence of the progesterone receptor antagonist Org 31710 in the nonconfluent cultures of cells from postmenopausal women, but no effect of an estrogen receptor antagonist was observed.

CONCLUSIONS

The normal ovarian surface epithelium is capable of steroid production, which is also often observed in tissue from ovarian epithelial tumors. Progesterone appeared to be a negative regulator of ovarian surface epithelial growth, while estradiol had no effect.

Molecular aspects of ovarian cancer. Is gene therapy the solution?

Genetic abnormalities of cancer cells are complex and usually nonspecific. Genetic anomalies specific to ovarian cancer have not been reported. This article focuses on what molecular anomalies are known in ovarian cancer and describes the first trials that have used transfer of genes to reestablish a normal cellular function in this disease. Suicide gene therapy has been the prototype of this new therapeutic approach.

Hormonal aspects of epithelial ovarian cancer: review of epidemiological evidence

Epithelial ovarian cancer is fairly common with high rates in Scandinavia, intermediate rates in western Europe and North America and low rates in the developing countries and in Japan. The 5-year survival rate is less than 40%. Increasing parity consistently gives a strong protection against epithelial ovarian cancer. A lesser degree of protection is probably derived from incomplete pregnancies and lactation. Ages at menarche and menopause are most probably weak predictors of epithelial ovarian cancer risk. Ever users of oral contraceptives (OC) have 30% lower risk compared to never users. The protection increases with duration of OC use, being about 50% after 5 years. The reduced risk among past OC users persists for at least 10 years after cessation of use. Results concerning hormone replacement therapy (HRT) and epithelial ovarian cancer risk are conflicting, but most data point to a weak or no association, but as an increasing number of women use HRT it still seems important to resolve any potential effect. Infertility adds to epithelial ovarian cancer risk in nulliparous women, while temporary fertility problems in parous women do not appear to increase risk. A possible independent risk effect of fertility drug use has not been easy to assess and remains unresolved. It has been particularly difficult to separate the effects of fertility drugs from those of infertility. Tubal ligation and hysterectomy convey protection against epithelial ovarian cancer, possibly through a suppressed ovarian hormone production. The causes of epithelial ovarian cancer are poorly understood, but reproductive hormones are thought to be involved in the aetiology. For a long time the 'incessant' and 'gonadotrophin' hypotheses have been promoted in relation to carcinogenesis. Both hypotheses find support in ovarian cancer epidemiology, and recent progress in molecular biology adds to the understanding of possible aetiological mechanisms. Another hypothesis focuses on the retrograde transport of contaminants or carcinogens through the Fallopian tubes. It is important to establish if the same risk factors apply to the various histological types of ovarian cancer, as particularly the mucinous ovarian tumours seem to present with different risk factors. Another question to resolve is if sporadic vs. inherited cases carry distinct risk profiles. As the hypotheses above do not explain all of the results derived from ovarian cancer epidemiology, there is a need to test additional hypotheses to possibly define preventive programmes and to come closer to the cause of ovarian cancer.