Signaling by estrogens and tamoxifen in the human endometrium

Tamoxifen is used as adjuvant treatment for postmenopausal breast cancer patients. The mechanism of action of tamoxifen in breast cancer patients is that tamoxifen inhibits growth of cancer cells by competitive antagonism for estrogens at the estrogen receptor (ER). In the endometrium, tamoxifen has an effect that varies with the ambient concentration of estrogen: in premenopausal women (high estrogen levels), tamoxifen displays an estrogen-antagonistic effect, while in postmenopausal women (low estrogen levels), tamoxifen displays an estrogen-agonistic mode of action. Here, using microarray technology we have compared estrogen signaling with tamoxifen signaling in the human endometrium. It was observed that on the one hand tamoxifen-treatment results in modulation of expression of specific genes (370 genes) and on the other hand tamoxifen-treatment results in modulation of a set of genes which are also regulated by estrogen treatment (142 genes). Upon focusing on regulation of proliferation, we found that tamoxifen-induced endometrial proliferation is largely accomplished by using the same set of genes as are regulated by estradiol. So, as far as regulation of proliferation goes, tamoxifen seems to act as estrogen agonist. Furthermore, tamoxifen-specific gene regulation may explain why tamoxifen-induced endometrial tumors behave more aggressively than sporadic endometrial tumors.

Genomic and nongenomic effects of estrogen signaling in human endometrial cells: involvement of the growth factor receptor signaling downstream AKT pathway

For the endometrium, estradiol and tamoxifen induce proliferation, and consequently, tamoxifen treatment of breast cancer results in a 2-fold to 7-fold increased risk for endometrial cancer. Here, the role of activation of growth factor receptor signaling in mediating the effects of estrogen and tamoxifen is determined. Microarray analysis of ECC-1 cells treated with estradiol or tamoxifen indicate that rapid responses to treatment (1 hour) are very distinct from long-term responses (>24 hours). Furthermore, estradiol and tamoxifen are observed to induce AKT activation. Comparing long-term estrogen- and tamoxifen-regulated genes with genes regulated by insulin-like growth factor 1 and amphiregulin reveals that the late effects of estrogen and tamoxifen signaling may partly be mediated via activation of growth factor receptor signaling pathways. It is hypothesized that both early and late effects of estrogen and tamoxifen signaling in the endometrium are partly mediated via the activation of growth factor receptor signaling, putatively at the level of AKT activation.

Preoperative predictors for residual tumor after surgery in patients with ovarian carcinoma

OBJECTIVES

Suboptimal debulking (>1 cm residual tumor) results in poor survival rates for patients with an advanced stage of ovarian cancer. The purpose of this study was to develop a prediction model, based on simple preoperative parameters, for patients with an advanced stage of ovarian cancer who are at risk of suboptimal cytoreduction despite maximal surgical effort.

METHODS

Retrospective analysis of 187 consecutive patients with a suspected clinical diagnosis of advanced-stage ovarian cancer undergoing upfront debulking between January 1998 and December 2003. Preoperative parameters were Karnofsky performance status, ascites and serum concentrations of CA 125, hemoglobin, albumin, LDH and blood platelets. The main outcome parameter was residual tumor >1 cm. Univariate and multivariate logistic regression was employed for testing possible prediction models. A clinically applicable graphic model (nomogram) for this prediction was to be developed.

RESULTS

Serum concentrations of CA 125 and blood platelets in the group with residual tumor >1 cm were higher in comparison to the optimally cytoreduced group (p < 0.0001 and <0.01, respectively). Serum albumin and hemoglobin levels were lower in the group with residual tumor (p < 0.0001 and <0.05, respectively). The frequency of preoperative ascites was higher in the group with residual tumor (p < 0.0005). The prediction model, consisting of CA 125 and albumin, for remaining with residual tumor showed an area under the receiver operating characteristics curve of 0.79. A nomogram for probability of residual tumor >1 cm based on serum levels of CA 125 and albumin was established.

CONCLUSION

Postoperative residual tumor despite maximal surgical effort can be predicted by preoperative CA 125 and serum albumin levels. With a nomogram based on these two parameters, probability of postoperative residual tumor in each individual patient can be predicted. This proposed nomogram may be valuable in daily routine practice for counseling and to select treatment modality.

Progesterone-mediated regulation of catechol-O-methyl transferase expression in endometrial cancer cells

The effects of estrogen and progesterone on the expression of estrogen-metabolizing enzymes such as catechol-O-methyl transferase (COMT) are not known. COMT converts genotoxic catecholestrogens to anticarcinogenic methoxyestrogens in the endometrium. The aim of this study is to investigate the effect of progesterone on COMT expression in well-differentiated endometrial cancer cells. The wild-type Ishikawa cell line as well as progesterone receptor A- or progesterone receptor B-transfected Ishikawa cells were used for in vitro studies. The regulation of COMT expression by progesterone was studied using Western blots, Hoechst dye DNA proliferation studies, and wild-type and/or site-directed mutagenesis of COMT promoter 1-luciferase reporter gene. Progesterone upregulated COMT protein expression in Ishikawa cells through progesterone receptor A isoform. COMT promoter activity was differentially regulated by the 3 half-site progesterone response elements in the COMT promoter. High doses of 2-ME2 inhibited Ishikawa cell proliferation. These data suggest that COMT expression is hormonally regulated in well-differentiated human endometrial cancer cells. COMT regulation and 2-ME2 production in the endometrium may affect endometrial carcinogenesis.

Difference in signalling between various hormone therapies in endometrium, myometrium and upper part of the vagina

BACKGROUND

Combined hormone treatments in post-menopausal women have different clinical responses on uterus and vagina; therefore, we investigated differences in steroid signalling between various hormone therapies in these tissues.

METHODS

A total of 30 post-menopausal women scheduled for hysterectomy were distributed into four subgroups: control-group (n = 9), Tibolone-group (n = 8); estradiol (E(2))-group (n = 7); E(2) + medroxyprogesterone acetate (MPA)-group (n = 6). Medication was administered orally every day for 21 days prior to removal of uterus and upper part of the vagina. Tissue RNA was isolated, and gene expression profiles were generated using GeneChip technology and analysed by cluster analysis and significance analysis of microarrays. Apoptosis and cell proliferation assays, as well as immunohistochemistry for hormone receptors were performed.

RESULTS

21-days of treatment with E(2), E(2) + MPA or tibolone imposes clear differential gene expression profiles on endometrium and myometrium. Treatment with E(2) only results in the most pronounced effect on gene expression (up to 1493 genes differentially expressed), proliferation and apoptosis. Tibolone, potentially metabolized to both estrogenic and progestagenic metabolites, shows some resemblance to E(2) signalling in the endometrium and, in contrast, shows significant resemblance to E(2) + MPA signalling in the myometrium. In the vagina the situation is entirely different; all three hormonal treatments result in regulation of a small number (4-73) of genes, in comparison to signalling in endometrium and myometrium.

CONCLUSION

Endometrium and myometrium differentially respond to the hormone therapies and use completely different sets of genes to regulate similar biological processes, while in this experiment the upper part of the vagina is hardly hormone responsive.

Breast cancer and climacteric complaints: Weighing up risks of hormone therapy against quality of life

Women with severe menopausal symptoms can, at their request, be treated effectively with hormone therapy. Good information about the advantages and disadvantages of hormone therapy should precede this decision. For women with breast cancer or an inherited increased risk of breast cancer and severe, often therapy-related climacteric symptoms, a high degree of reticence is appropriate in relation to hormone therapy. If the quality of life is seriously affected in these often-young women with these iatrogenic climacteric complaints, then careful consideration must be given to the various treatment modalities.

Inadequate office endometrial sample requires further evaluation in women with postmenopausal bleeding and abnormal ultrasound results

OBJECTIVE

To determine whether further histologic assessment can be omitted after office sampling produced a nondiagnostic specimen.

METHODS

Data were retrieved from a prospective cohort study of 913 women presenting with postmenopausal bleeding. This study was limited to women with an endometrial thickness either 5 mm or greater or that could not be measured, and in whom an endometrial biopsy performed in the office yielded nondiagnostic results.

RESULTS

Endometrial thickness was nonreassuring or unknown in 516 women, of whom 403 (78.1%) underwent office endometrial sampling. In 66 women the amount of tissue obtained was not sufficient for pathologic characterization. Further investigation revealed an endometrial malignancy in 3 of these 66 women and atypical hyperplasia in 1.

CONCLUSION

In women with postmenopausal bleeding and a nonreassuring transvaginal ultrasound evaluation, a nondiagnostic office endometrial sample does not rule out endometrial cancer and further endometrial sampling is advisable.

Concomitant radiotherapy and hyperthermia for primary carcinoma of the vagina: A cohort study

OBJECTIVE

To evaluate the supplementary value of adding hyperthermia to radiotherapy in patients with primary vaginal cancer.

STUDY DESIGN

Cohort of 44 patients diagnosed with primary vaginal cancer between 1990 and 2002 was assessed. Survival rates and median survival of patients with primary vaginal cancer undergoing radiotherapy with and without hyperthermia were compared. Hyperthermia was solely added to radiotherapy in case of a tumor size >4 cm in diameter for FIGO stage III disease.

RESULTS

The calculated overall 5-year survival of primary vaginal cancer was 63%. In comparison to histologic high grade tumors, higher survival rates for histologic low grade tumors were calculated. For FIGO stage III of disease, the addition of hyperthermia to radiotherapy for tumors >4 cm in diameter resulted similar survival rates and median survival when compared to those achieved by radiotherapy as monotherapy in tumors of <4 cm in diameter.

CONCLUSIONS

The addition of hyperthermia to radiotherapy might result in better survival rates in primary vaginal cancer for tumors >4 cm in diameter. The supplementary effect of hyperthermia to radiotherapy may be a feasible and beneficial approach in the treatment of vaginal cancer.

The incidence of parametrial tumor involvement in select patients with early cervix cancer is too low to justify parametrectomy

OBJECTIVE

To determine the incidence of parametrial involvement in a select group of patients with early cervical cancer.

METHODS

We retrospectively reviewed the records of patients with cervical cancer and a maximum tumor diameter of 2 cm, infiltration depth<10 mm and negative pelvic lymph nodes who underwent a radical hysterectomy in two university hospitals. In addition, the literature was reviewed.

RESULTS

103 patients were identified in our databases that met the abovementioned criteria. In two of these patients (1.94%), parametrial involvement was found. Both patients had LVSI. Literature review revealed 696 patients described in three studies that satisfied the selection criteria. Three (0.43%) of these patients had parametrial involvement. In patients with early stage cervical carcinoma, tumor size<2 cm, infiltration depth<10 mm, negative pelvic lymph nodes and absent LVSI the risk of parametrial involvement is 0.63%.

CONCLUSION

Because of a very low risk on parametrial involvement, patients who fulfil strict selection criteria could be candidates for conization and pelvic lymphadenectomy instead of more extensive surgery. Morbidity and pregnancy complications may decrease while it is unlikely that survival will be compromised.

No efficacy of annual gynaecological screening in BRCA1/2 mutation carriers; an observational follow-up study

BRCA1/2 mutation carriers are offered gynaecological screening with the intention to reduce mortality by detecting ovarian cancer at an early stage. We examined compliance and efficacy of gynaecological screening in BRCA1/2 mutation carriers. In this multicentre, observational, follow-up study we examined medical record data of a consecutive series of 888 BRCA1/2 mutation carriers who started annual screening with transvaginal ultrasonography and serum CA125 between 1993 and 2005. The women were annually screened for 75% of their total period of follow-up. Compliance decreased with longer follow-up. Five of the 10 incident cancers were interval tumours, diagnosed in women with a normal screening result within 3–10 months before diagnosis. No difference in stage distribution between incident screen-detected and interval tumours was found. Eight of the 10 incident cancers were stage III/IV (80%). Cancers diagnosed in unscreened family members had a similar stage distribution (77% in stage III/IV). The observed number of cases detected during screening was not significantly higher than expected (Standardized Incidence Ratio (SIR): 1.5, 95% confidence interval: 0.7–2.8). For the subgroup that was fully compliant to annual screening, a similar SIR was found (1.6, 95% confidence interval: 0.5–3.6). Despite annual gynaecological screening, a high proportion of ovarian cancers in BRCA1/2 carriers are interval cancers and the large majority of all cancers are diagnosed in advanced stages. Therefore, it is unlikely that annual screening will reduce mortality from ovarian cancer in BRCA1/2 mutation carriers.

Tumour characteristics, survival and prognostic factors of hereditary breast cancer from BRCA2-, BRCA1- and non-BRCA1/2 families as compared to sporadic breast cancer cases

AIM OF THE STUDY

Results on tumour characteristics and survival of hereditary breast cancer (BC), especially on BRCA2-associated BC, are inconclusive. The prognostic impact of the classical tumour and treatment factors in hereditary BC is insufficiently known.

METHODS

We selected 103 BRCA2-, 223 BRCA1- and 311 non-BRCA1/2 BC patients (diagnosis 1980-2004) from the Rotterdam Family Cancer Clinic. To correct for longevity bias, analyses were also performed while excluding index patients undergoing DNA testing 2 years after BC diagnosis. As a comparison group, 759 sporadic BC patients of comparable age at and year of diagnosis were selected. We compared tumour characteristics, the occurrence of ipsilateral recurrence (LRR) and contralateral BC (CBC) as well as distant disease-free (DDFS), BC-specific (BCSS) and overall survival (OS) between these groups. By multivariate modelling, the prognostic impact of tumour and treatment factors was investigated separately in hereditary BC.

RESULTS

We confirmed the presence of the particular BRCA1-phenotype. In contrast, tumour characteristics of BRCA2-associated BC were similar to those of non-BRCA1/2 and sporadic BC, with the exception of a high risk of CBC (3.1% per year) and oestrogen-receptor (ER)-positivity (83%). No significant differences between BRCA2-associated BC and other BC subgroups were found with respect to LRR, DDFS, BCSS and OS. Independent prognostic factors for BC-specific survival in hereditary BC (combining the three subgroups) were tumour stage, adjuvant chemotherapy, histologic grade, ER status and a prophylactic (salpingo-)oophorectomy.

CONCLUSIONS

Apart from the frequent occurrence of contralateral BC and a positive ER-status, BRCA2-associated BC did not markedly differ from other hereditary or sporadic BC. Our observation that tumour size and nodal status are prognostic factors also in hereditary BC implies that the strategy to use these factors as a proxy for ultimate mortality appears to be valid also in this specific group of patients.

Improving the existing diagnostic strategy by accounting for characteristics of the women in the diagnostic work up for postmenopausal bleeding

OBJECTIVES

The aim of this study was to evaluate whether the efficiency of the current diagnostic work up following postmenopausal bleeding could be improved by diagnostic strategies that take into account characteristics of the women in addition to the currently recommended transvaginal measurement of endometrial thickness to determine for subsequent histological assessment.

DESIGN

Multicenter, prospective cohort study.

SETTING

A university hospital and seven teaching hospitals in the Netherlands.

SAMPLE

Consecutive women not using hormone replacement therapy, presenting with postmenopausal bleeding.

METHODS

Five hundred and forty women underwent transvaginal sonography, and in case of endometrial thickness (double layer) above 4 mm, subsequent endometrial sampling was performed. Presence of carcinoma was ruled out by the absence of abnormalities in histological specimen or by an uneventful follow up of at least 6 months.

MAIN OUTCOME MEASURES

Probability of endometrial carcinoma was estimated by multivariable logistic regression models. For each diagnostic strategy, we calculated diagnostic accuracy (area under receiver operating characteristic curve [AUC]), negative predictive value (NPV) and the number of diagnostic procedures.

RESULTS

A strategy with transvaginal sonography alone with a fixed threshold incorrectly classified 0.7% of the women as nonmalignant (NPV: 99.3% [98.5-100%]), with 97% sensitivity and 56% specificity. A strategy integrating characteristics of the women with transvaginal sonography could result in less false reassurances (NPV: 99.6% [99.2-100%]), with only marginal decrease in diagnostic procedures, or a minor increase in false reassurances (NPV: 99.0% [98.3-100%]), with a substantial reduction (15-20%) in the procedures. AUCs associated with these strategies could improve from 0.76 (0.73-0.79) for transvaginal sonography alone to 0.90 (0.87-0.93) for the integrated strategy.

CONCLUSION

Taking into account the characteristics of the women could increase the efficiency of the diagnostic work up for postmenopausal bleeding.

The hormone replacement therapy drug tibolone acts very similar to medroxyprogesterone acetate in an estrogen-and progesterone-responsive endometrial cancer cell line

Tibolone, a steroidogenic compound with both estrogenic and progestagenic properties, is used as an alternative for estrogen or estrogen plus progesterone hormone therapy for the treatment of symptoms associated with menopause and osteoporosis. We have evaluated whether the effect of tibolone on a human endometrial cell line is similar to, or comparable with, the effect of estradiol (E(2)), medroxyprogesterone acetate (MPA) or E(2) + MPA treatment. Using stable transfection techniques, the estrogen receptor (ER) expressing human endometrial cancer cell line, ECC1, was altered to also express both progesterone receptors (PRs). These cells were then used to assess growth regulation and expression profiling (Affymetrix U133plus2) under the influence of E(2) (1 nM), MPA (1 nM), E(2) + MPA or tibolone (100 nM). Growth assessment and comparison of profiles indicate that tibolone behaves predominantly like MPA. Furthermore, regulation of prereplication complex genes, such as the minichromosome maintenance genes, could be involved in the observed strong inhibition of growth by tibolone as well as MPA. In addition, in total, 15 genes were found to be specific for tibolone treatment. These genes were predominantly involved in regulation of the cell cycle and differentiation.

Optimum number of oocytes for a successful first IVF treatment cycle

Ovarian stimulation in IVF allows selection of embryos for transfer, but may have detrimental effects on oocyte and embryo quality and endometrial receptivity. This study investigated the optimal response to ovarian stimulation in terms of number of oocytes for achieving pregnancy in a first IVF cycle. Data from 7422 women who underwent their first IVF cycle for standard indications were analysed. All had been treated with exogenous gonadotrophins and gonadotrophin releasing hormone (GnRH) agonist co-treatment in a long down-regulation protocol between 1990 and 1995. Pregnancy rates in relation to the number of obtained oocytes were adjusted for age, fecundity, subfertility cause, gonadotrophin dosage, type of luteal support, and number of transferred embryos by multivariate analysis. Of the 7422 women who underwent oocyte retrieval, overall 85% had an embryo transfer and 24% conceived. The highest pregnancy rates per embryo transfer and per started cycle were observed when 13 oocytes were obtained (31 and 28%, respectively). This study supports the concept of an optimal range of oocytes obtained in response to ovarian stimulation for IVF, below and above which outcomes are compromised.

Pleomorphic adenoma of the vulva: a review illustrated by a clinical case

The pleomorphic adenoma of the vulva is an extremely scarce diagnosis. This form of neoplasm is more frequently observed in other topographic sites of the human body. Treatment modalities largely derive from experiences with the pleomorphic adenoma located in these other sites. As a result of similarity with other tumors and scarcity of the neoplasm, the diagnosis of pleomorphic adenoma of the vulva is easily missed in daily routine practice. Recurrences of this neoplasm are frequently observed with an estimated incidence of malignant transformation of 25%. Addressing this previously mentioned issue, an extensive surgical excision and long-term follow-up is advocated. This report is illustrated by the case of a 66-year-old woman who was admitted to our hospital with a pleomorphic adenoma of the vulva, diagnosed by pathologic assessments following surgical excision. As a result of the rarity of this diagnosis, characteristics and treatment of extravulvar in addition to vulvar localizations of the pleomorphic adenoma are reviewed.

Does subfertility explain the risk of poor perinatal outcome after IVF and ovarian hyperstimulation?

BACKGROUND

The primary objective of this study was to investigate whether subfertility explains poor perinatal outcome after assisted conception. A secondary objective was to test the hypothesis that ovarian hyperstimulation rather than the IVF procedure may influence the perinatal outcome.

METHODS

Using data from a Dutch population-based historical cohort of women treated for subfertility, we compared perinatal outcome of singletons conceived after controlled ovarian hyperstimulation (COHS) and IVF (IVF + COHS; n = 2239) with perinatal outcome in subfertile women who conceived spontaneously (subfertile controls; n = 6343) and in women who only received COHS (COHS only; n = 84). Furthermore, we compared perinatal outcome of singletons conceived after the transfer of thawed embryos with (Stim + Cryo; n = 66) and without COHS (Stim - Cryo; n = 73).

RESULTS

The odds ratios (ORs) for very low birthweight (<1500 g) and low birthweight (1500-2500 g) were 2.8 [95% confidence interval (95% CI) 1.9-3.9] and 1.6 (95% CI 1.2-1.8) in the IVF + COHS group compared with the subfertile control group. The ORs for very preterm birth (<32 weeks) and for preterm birth (32-37 weeks) were 2.0 (95% CI 1.4-2.9) and 1.5 (95% CI 1.3-1.8), respectively. Adjustment for confounders did not materially change these risk estimates. The difference in risk between the COHS-only group and the subfertile group was significant only for very low birthweight (OR 3.5; 95% CI 1.1-11.4), but the association became weaker after adjustment for maternal age and primiparity (OR 3.1; 95% CI 1.0-10.4). No significant difference in birthweight and preterm delivery was found between the group of children conceived after ovarian stimulation/ovulation induction and (Stim + Cryo) and the group of children conceived after embryo transfer of thawed embryos in a spontaneous cycle without ovarian stimulation/ovulation induction (Stim - Cryo).

CONCLUSIONS

The poor perinatal outcome in this database could not be explained by subfertility and suggests that other factors may be important in the known association between assisted conception and poor perinatal outcome.

Histological and immunohistochemical evaluation of postmenopausal endometrium after 3 weeks of treatment with tibolone, estrogen only, or estrogen plus progestagen

OBJECTIVE

To evaluate histological and immunohistochemical parameters of short-term (21 days) tibolone, estrogen-only, and estrogen+progestagen treatment in the human postmenopausal endometrium.

DESIGN

An observational, open, nonrandomized, controlled study.

SETTING

Three collaborating centers: Amphia Hospital in Breda, Albert Schweitzer Hospital in Dordrecht, Erasmus Medical Center in Rotterdam, the Netherlands.

PATIENT(S)

Thirty healthy, postmenopausal women.

INTERVENTION(S)

Control group (n = 9), no hormonal treatment; tibolone group (n = 8), patients were treated with 2.5 mg of tibolone (administered orally) every day, starting 21 days before surgery; estrogen group (n = 7), patients were treated with 2 mg of E(2) (Zumenon, administered orally; Zambon, Amerfoort; The Netherlands) every day, starting 21 days before surgery; estrogen+progestagen group (n = 6), patients were treated with 2 mg of E(2) (Zumenon, administered orally) and 5 mg of medroxyprogesterone acetate (administered orally) every day, starting 21 days before surgery.

MAIN OUTCOME MEASURE(S)

Uterine tissues were collected, and two pathologists independently assessed histology. Immunohistochemical parameters measured were estrogen receptor alpha, progesterone receptor A/B, Hoxa10, Ki67, and Bcl-2.

RESULT(S)

On the basis of a number of histological and immunohistochemical parameters measured after 21 days of treatment, it was observed that tibolone displays clearly less stimulation (proliferation) of the human postmenopausal endometrium than estrogen at the beginning of a treatment, but the stimulation is higher than with estrogen+progestagen.

CONCLUSION(S)

Short-term (21 days) tibolone treatment results in a small stimulation of proliferation of the endometrium, and because long-term treatment with tibolone has been demonstrated to lead to an atrophic endometrium, it may be concluded that the stimulatory effect, as observed in this study, is transient in nature. It is hypothesized that tibolone first displays a more estrogenic mode of action, which over time, is counterbalanced by the induction of its progestagenic properties.

Stage III and IV endometrial cancer: a 20-year review of patients

In advanced endometrial cancer, the importance of peritoneal cytology and optimal surgical cytoreduction remain subjects of discussion. We evaluated our clinical experience of 67 patients with FIGO stage III and IV endometrial cancer treated in the Erasmus Medical Centre in Rotterdam over a 20-year period with an emphasis on stage IIIA disease based on positive cytology only and optimal cytoreduction. Lymphadenectomy was not routinely performed and peritoneal cytology was examined in 74% of the patients. Stage IIIA disease was found in 33 patients, 10 of whom had positive cytology only. Analysis showed that incidence of recurrence and survival rates of patients with stage IIIA disease based on positive cytology only were comparable with stage IIIA disease based on other factors. In 50 patients, it was possible to remove all macroscopic tumor, whereas in 17 patients, an optimal cytoreduction was not achievable. The 2- and 5-year survival rates after optimal cytoreduction were 82.2% and 65.6%; where this could not be achieved, these figures were 50.8% and 40.6%. In advanced endometrial cancer patients, positive peritoneal cytology seems an important prognostic factor in stage IIIA disease if lymph node status is unknown. Survival is improved if optimal surgical cytoreduction is achievable.

Growth regulation and transcriptional activities of estrogen and progesterone in human endometrial cancer cells

Estrogen-stimulated growth of the malignant human endometrium can be balanced by the differentiating properties of progesterone. To study the molecular basis behind this, gene expression profiling was performed using complementary DNA microarray analysis. In this study, the human endometrial cancer cell lines ECC-1 and PRAB-36 were used as models. The ECC-1 cell line, which expresses high levels of estrogen receptor alpha and is stimulated in growth by estrogens, was used to study estrogen regulation of gene expression. The Ishikawa sub-cell line PRAB-36, expressing both PRA and PRB, progesterone receptor isoforms, and inhibited in growth by progestagens, was used to study progesterone regulation of gene expression. Using these two well-differentiated human endometrial cancer cell lines, 148 estrogen- and 148 progesterone-regulated genes were identified. After functional classification, the estrogen- and progesterone-regulated genes could be categorized in different biologically relevant groups. Within the group of "cell growth and/or maintenance," 81 genes were clustered, from which a number of genes could be involved in arranging the cross talk that exists between estrogen and progesterone signaling. On the basis of analysis of the current findings, it is hypothesized that cross talk between estrogen and progestagen signaling does not occur by counterregulation of single genes, but rather at the level of differential regulation of different genes within the same functional families.

Ligand-controlled interaction of histone acetyltransferase binding to ORC-1 (HBO1) with the N-terminal transactivating domain of progesterone receptor induces steroid receptor coactivator 1-dependent coactivation of transcription

Modulators of cofactor recruitment by nuclear receptors are expected to play an important role in the coordination of hormone-induced transactivation processes. To identify such factors interacting with the N-terminal domain (NTD) of the progesterone receptor (PR), we used this domain as bait in the yeast Sos-Ras two-hybrid system. cDNAs encoding the C-terminal MYST (MOZ-Ybf2/Sas3-Sas2-Tip60 acetyltransferases) domain of HBO1 [histone acetyltransferase binding to the origin recognition complex (ORC) 1 subunit], a member of the MYST acetylase family, were thus selected from a human testis cDNA library. In transiently transfected CV1 cells, the wild-type HBO1 [611 amino acids (aa)] enhanced transcription mediated by steroid receptors, notably PR, mineralocorticoid receptor, and glucocorticoid receptor, and strongly induced PR and estrogen receptor coactivation by steroid receptor coactivator 1a (SRC-1a). As assessed by two-hybrid and glutathione-S-transferase pull-down assays, the HBO1 MYST acetylase domain (aa 340-611) interacts mainly with the NTD, and also contacts the DNA-binding domain and the hinge domains of hormone-bound PR. The HBO1 N-terminal region (aa 1-340) associates additionally with PR ligand-binding domain (LBD). HBO1 was found also to interact through its NTD with SRC-1a in the absence of steroid receptor. The latter coassociation enhanced specifically activation function 2 activation function encompassed in the LBD. Conversely, the MYST acetylase domain specifically enhanced SRC-1 coupling with PR NTD, through a hormone-dependent mechanism. In human embryonic kidney 293 cells expressing human PRA or PRB, HBO1 raised selectively an SRC-1-dependent response of PRB but failed to regulate PRA activity. We show that HBO1 acts through modification of an LBD-controlled structure present in the N terminus of PRB leading to the modulation of SRC-1 functional coupling with activation function 3-mediated transcription. Importantly, real-time RT-PCR analysis also revealed that HBO1 enhanced SRC-1 coactivation of PR-dependent transcription of human endogenous genes such as alpha-6 integrin and 11beta-hydroxydehydrogenase 2 but not that of amphiregulin. Immunofluorescence and confocal microscopy of human embryonic kidney-PRB cells demonstrated that the hormone induces the colocalization of HBO1 with PR-SRC-1 complex into nuclear speckles characteristic of PR-mediated chromatin remodeling. Our results suggest that HBO1 might play an important physiological role in human PR signaling.

Analysis of estrogen agonism and antagonism of tamoxifen, raloxifene, and ICI182780 in endometrial cancer cells: a putative role for the epidermal growth factor receptor ligand amphiregulin

OBJECTIVES

In different tissues, estrogens, selective estrogen receptor modulators (SERMs), and anti-estrogens exert different biologic activities. For the endometrium, estradiol and tamoxifen induce proliferation, and because of this, tamoxifen treatment of breast cancer patients results in a two- to sevenfold increased risk for development of endometrial cancer. Use of raloxifene, or the anti-estrogen ICI182780, does not result in such an increased risk. The objective of the current study was to generate and analyze gene expression profiles that reflect the transcriptional response of the human endometrium to estradiol, SERMs like tamoxifen and raloxifene, and anti-estrogens like ICI182780.

METHODS

Transient transfections were performed to analyze the transcriptional response of ECC-1 cells to estradiol, tamoxifen, raloxifene, and ICI182780. Subsequently, to reveal the molecular mechanism of action, gene expression profiles were generated and some of the observed regulated genes were confirmed by Northern blotting. Biostatistical methods were employed to analyze the expression profile results further, and amphiregulin effects on ECC-1 cell signaling were investigated using Northern and Western blotting, and 3H-thymidine incorporation.

RESULTS

Analysis of the profiles revealed that estradiol, tamoxifen, raloxifene, and ICI182780 influence the same biologic processes, but they do so via regulation of different sets of genes. Upon construction of a genetic network it was observed that the largest possible network centered on epidermal growth factor (EGF) receptor signaling. Furthermore, the EGF receptor ligand amphiregulin was differentially regulated by all four ligands. Next it was shown that amphiregulin indeed could stimulate EGF receptor signaling in ECC-1 cells. Based on these results, it was hypothesized that EGF receptor signaling could differentially be affected by estrogen, tamoxifen, raloxifene, and ICI182780 because these four compounds differentially regulate the EGF receptor ligand amphiregulin.

CONCLUSIONS

Regulation of amphiregulin coincides with the described in vivo effect of the four ligands on the endometrium. Therefore, it is possible that modulation of EGF receptor signaling is a significant player in estrogen-agonistic growth of the endometrium and needs to be investigated further.

What is the role of dose-dense therapy?

The introduction of paclitaxel/platinum combination chemotherapy and (interval) debulking surgery has significantly improved the prognosis of patients with ovarian cancer. Yet, many patients die of drug-resistant disease. Second-line chemotherapy may result in prolonged secondary remissions with alleviation of symptoms and improvement of quality of life. The response to second-line chemotherapy is strongly related to platinum sensitivity. More than 60% of platinum-sensitive patients respond to a re-challenge with platinum-containing chemotherapy. In platinum-resistant patients, on the contrary, the response rate to a re-challenge with 3-weekly platinum or any nonplatinum chemotherapy is less than 20%. The response to dose-dense weekly platinum-based regimens ranged from 48% to 64% in platinum-resistant patients. Moreover, the majority of the patients responded within 8 weeks after the start of the treatment. The progression-free survival ranged from a median of 5 months in a study using cisplatin/etoposide, to 11 months in a study with paclitaxel/carboplatin. The median survival was 11-15 months. The outpatient weekly paclitaxel/carboplatin regimen, with paclitaxel at a dose of 90 mg/m(2) and carboplatin at area under the curve 4, seems similarly effective and is better tolerated. Dose-dense weekly paclitaxel/carboplatin is an effective and well-tolerated therapy for platinum-sensitive, as well as platinum-resistant tumors. Responses to therapy are observed within 8 weeks in the majority of the patients. Whether a weekly regimen indeed is more effective than 3-weekly paclitaxel/carboplatin needs to be answered in a randomized study.

Differences in invasive capacity of endometrial cancer cell lines expressing different progesterone receptor isotypes: possible involvement of cadherins

OBJECTIVE

Loss of expression of progesterone receptors (PR) in endometrial cancer is related to a more invasive and metastatic phenotype. In this study we aim to investigate whether selective loss of PRA or PRB affects the invasive capacity of endometrial cancer cells.

METHODS

cDNA microarrays were performed to compare gene expression profiles of a set of endometrial cancer sub-cell lines expressing PRA and/or PRB. In vitro invasion assays were performed to assess whether differences in gene expression between the lines were reflected by their invasive behavior.

RESULTS

It was observed that cell lines that express only PRA express higher levels of cadherins, and show a lower level of invasion compared to cell lines that express PRB. When cadherin function was inhibited in exclusively PRA-expressing cell lines, an increase of in vitro invasion was observed. In support of these findings, it was observed that in higher grade and more invasive endometrial cancer, expression of E-cadherin decreased.

CONCLUSIONS

These results indicate that relative loss of PRA during progression of endometrial cancer can have a negative impact on cadherin expression, which may lead to development of a more metastatic phenotype.