The correlation between the response to progestogen treatment and the expression of progesterone receptor B and 17beta-hydroxysteroid dehydrogenase type 2 in human endometrial carcinoma

Role of steroid receptor-associated and regulated protein in tumor progression and progesterone receptor signaling in endometrial cancer

BACKGROUND

Steroid receptor-associated and regulated protein (SRARP) suppresses tumor progression and modulates steroid receptor signaling by interacting with estrogen receptors and androgen receptors in breast cancer. In endometrial cancer (EC), progesterone receptor (PR) signaling is crucial for responsiveness to progestin therapy. The aim of this study was to investigate the role of SRARP in tumor progression and PR signaling in EC.

METHODS

Ribonucleic acid sequencing data from the Cancer Genome Atlas, Clinical Proteomic Tumor Analysis Consortium, and Gene Expression Omnibus were used to analyze the clinical significance of SRARP and its correlation with PR expression in EC. The correlation between SRARP and PR expression was validated in EC samples obtained from Peking University People's Hospital. SRARP function was investigated by lentivirus-mediated overexpression in Ishikawa and HEC-50B cells. Cell Counting Kit-8 assays, cell cycle analyses, wound healing assays, and Transwell assays were used to evaluate cell proliferation, migration, and invasion. Western blotting and quantitative real-time polymerase chain reaction were used to evaluate gene expression. The effects of SRARP on the regulation of PR signaling were determined by co-immunoprecipitation, PR response element (PRE) luciferase reporter assay, and PR downstream gene detection.

RESULTS

Higher SRARP expression was significantly associated with better overall survival and disease-free survival and less aggressive EC types. SRARP overexpression suppressed growth, migration, and invasion in EC cells, increased E-cadherin expression, and decreased N-cadherin and Wnt family member 7A ( WNT7A ) expression. SRARP expression was positively correlated with PR expression in EC tissues. In SRARP -overexpressing cells, PR isoform B (PRB) was upregulated and SRARP bound to PRB. Significant increases in PRE-based luciferase activity and expression levels of PR target genes were observed in response to medroxyprogesterone acetate.

CONCLUSIONS

This study illustrates that SRARP exerts a tumor-suppressive effect by inhibiting the epithelial-mesenchymal transition via Wnt signaling in EC. In addition, SRARP positively modulates PR expression and interacts with PR to regulate PR downstream target genes.

Regulation of progesterone receptor expression in endometriosis, endometrial cancer, and breast cancer by estrogen, polymorphisms, transcription factors, epigenetic alterations, and ubiquitin-proteasome system

The uterus and breasts are hormone-responsive tissues. Progesterone and estradiol regulate gonadotropin secretion, prepare the endometrium for implantation, maintain pregnancy, and regulate the differentiation of breast tissue. Dysregulation of these hormones causes endometriosis, endometrial cancer, and breast cancer, damaging the physical and mental health of women. Emerging evidence has shown that progesterone resistance or elevated progesterone activity is the primary hormonal substrate of these diseases. Since progesterone acts through its specific nuclear receptor, the abnormal expression of the progesterone receptor (PR) dysregulates progesterone function. This review discusses the regulatory mechanisms of PR expression in patients with endometriosis, and endometrial or breast cancer, including estrogen, polymorphisms, transcription factors, epigenetics, and the ubiquitin-proteasome system. (1) Estrogen promotes the expression of PRA (a PR isoform) mRNA and protein through the interaction of estrogen receptors (ERs) and Sp1 with half-ERE/Sp1 binding sites. ERs also affect the binding of Sp1 and Sp1 sites to promote the expression of PRB (another PR isoform)(2) PR polymorphisms, mainly PROGINS and + 331 G/A polymorphism, regulate PR expression by affecting DNA methylation and transcription factor binding. (3) The influence of epigenetic alterations on PR expression occurs through DNA methylation, histone modification, and microRNA. (4) As one of the main protein degradation pathways in vivo, the ubiquitin-proteasome system (UPS) regulates PR expression by participating in protein degradation. These mechanisms may provide new molecular targets for diagnosing and treating endometriosis, endometrial, and breast cancer.

Progestin Resistance and Corresponding Management of Abnormal Endometrial Hyperplasia and Endometrial Carcinoma

With a younger tendency in morbidity age, endometrial cancer (EC) incidence has grown year after year. Worse, even more commonly occurring is endometrial hyperplasia (EH), which is a precancerous endometrial proliferation. For young women with early EC and EH who want to preserve fertility, progestin therapy has been utilized as a routine fertility-preserving treatment approach. Nevertheless, progestin medication failure in some patients is mostly due to progestin resistance and side effects. In order to further analyze the potential mechanisms of progestin resistance in EH and EC, to provide theoretical support for effective therapeutic strategies, and to lay the groundwork for searching novel treatment approaches, this article reviews the current therapeutic effects of progestin in EH and EC, as well as the mechanisms and molecular biomarkers of progestin resistance, and systematically expounds on the potential therapeutic methods to overcome progestin resistance.

Genistein induces long-term expression of progesterone receptor regardless of estrogen receptor status and improves the prognosis of endometrial cancer patients

Progesterone is used to treat uterine endometrial cancer in young patients wishing to preserve their fertility as well as in advanced or recurrent patients, but its response rate is limited. The antitumor effect of progesterone is mediated by progesterone receptor (PR) binding. Hence, loss of progesterone’s therapeutic effect, i.e., development of progesterone resistance, is mainly due to decreased PR expression. However, little is known about underlying mechanisms that regulate PR expression. Immunohistochemistry analysis of specimens from 31 young, endometrial cancer patients showed that elevated PR expression significantly increased (P < 0.05) rates of progression-free and overall survival. We investigated mechanisms of regulating PR expression and suppressing cell proliferation using genistein, a chemotherapeutic agent against different cancers. Genistein inhibits cell growth by inducing cell cycle arrest in G2 and apoptosis; moreover, it upregulates prolonged expression of PR-B and forkhead box protein O1, regardless of estrogen receptor alpha expression in endometrial cancer cells. Genistein-induced PR expression decreases CCAAT/enhancer binding protein beta expression and activates c-Jun N-terminal kinase pathway, rather than causing epigenetic alterations of the PR promoter. Therefore, increased PR expression is an important antitumor effect of genistein. This may help to improve the response rates of fertility-sparing treatments for young patients.

Efficacy of the LNG-IUS for treatment of endometrial hyperplasia and early stage endometrial cancer: Can biomarkers predict response?

Endometrial Cancer (EC) is the most common gynaecologic malignancy in the developed world, and is increasing in premenopausal women. The surgical standard of care for early-stage EC is not possible in women with concurrent comorbidities or women who desire a fertility sparing approach. The Levonorgestrel Intrauterine System (LNG-IUS) is gaining traction as an alternative treatment for endometrial hyperplasia and early stage EC in inoperable women. Whilst early evidence appears promising, predictive biomarkers need to be established to determine non-responders, which make up one in three women. This timely review discusses the current literature around the identification of clinical, molecular and novel biomarkers that show potential to predict response to progesterone treatment, including the LNG-IUS.

Relationship between the expression of oestrogen receptor and progesterone receptor and 18F-FDG uptake in endometrial cancer

Background: Progestogens have been widely used for the treatment of inoperable endometrial cancer or younger patients with endometrial cancer. Identifying markers that are predictive of a response to progestogens is critical for successful therapy. Molecular imaging with ¹⁸F^-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) can provide metabolic phenotypic information of many malignancies. We investigated whether estrogen receptor (ER)/progestogen receptor (PR) status is correlated with ¹⁸F-FDG uptake, and whether ¹⁸F-FDG PET/CT could be useful for predicting ER/PR status in endometrial cancer.

Results: Endometrial cancers in the ER-positive group had lower SUVmax than those in the ER-negative group (12.3 ± 6.2 vs. 19.9 ± 6.6, respectively; P = 0.003). Endometrial cancers in the PR-positive group also had lower SUVmax than those in the PR-negative group (12.4 ± 6.2 vs. 20.0 ± 6.9, respectively; P = 0.005). Multivariate analysis indicated that SUVmax and tumour differentiation grade were significantly associated with both ER and PR status (P = 0.027 and P = 0.044, respectively). ER expression was predicted with an accuracy of 74.2% when a SUVmax value of 15.3 was used as a cutoff point for analysis. Similarly, PR expression was predicted with an accuracy of 74.2%, when a SUVmax value of 15.95 was used as the threshold for analysis.

Conclusion: Higher ¹⁸F-FDG accumulation in endometrial cancers is correlated with negative ER/PR expression. ¹⁸F-FDG PET/CT may be used to predict the status of ER/PR and thus aid in optimal treatment decision in endometrial cancers.

Methods: We carried out a retrospective analysis on 62 endometrial cancer patients who underwent ¹⁸F-FDG PET/CT before radical treatment. The maximum of standardized uptake value (SUVmax) was calculated from the ¹⁸F-FDG accumulation of the primary tumor. The relationship between SUVmax and ER/PR status was analyzed.

Diabetes mellitus and responsiveness of endometrial hyperplasia and early endometrial cancer to conservative treatment

Objective: The conservative treatment of endometrial hyperplasia without atypia (HWA), atypical endometrial hyperplasia (AH/EIN) and early endometrioid carcinoma (EEC) is based on progestins. We aimed to assess whether diabetes mellitus affects the responsiveness of HWA, AH/EIN and EEC to conservative treatment, through a systematic review and meta-analysis. Study design: Electronic databases were searched for studies assessing the outcome of conservative treatment in HWA, AH/EIN and EEC, stratified based on the diagnosis of diabetes mellitus. The association of diabetes mellitus with treatment failure was assessed by using odds ratio (OR). A p-value  < .05 was considered significant. The risk of publication bias was assessed by using a funnel plot. A subgroups analyses was performed based on histologic diagnosis of benignity (HWA) or premalignancy/malignancy (AH/EIN or EEC). Results: Six studies with 876 patients (383 HWA, 365 AH/EIN and 128 EEC) were included. Overall, diabetes mellitus was not associated with outcome of treatment (OR = 1.20; p = .62). The association was not significant in both the HWA subgroup (OR = 0.95; p = .93) and in AH/EIN and EEC subgroup (OR = 1.43; p = .46). There was no significant risk of publication bias. Conclusions: Diabetes mellitus does not affect the outcome of conservative treatment in HWA, AH/EIN and EEC.

Local estrogen metabolism (intracrinology) in endometrial cancer: A systematic review

Endometrial cancer (EC) is the most common malignancy of the female gynaecological tract and increased exposure to estrogens is a risk factor. EC cells are able to produce estrogens locally using precursors like, among others, adrenal steroids present in the serum. This is referred to as local estrogen metabolism (or intracrinology) and consists of a complex network of multiple enzymes. Particular relevant to the final generation of active estrogens in endometrial cells are: steroid sulfatase (STS), estrogen sulfotransferase (SULT1E1), aromatase (CYP19A1), 17β-hydroxysteroid dehydrogenase (HSD17B) type 1 and type 2. During the last decades, a plethora of studies explored the level of these enzymes in EC but contrasting data were reported, which generated vigorous debate and controversies. Several reviews attempted at clarifying some of the debated issues, but published reviews are based on investigator-defined bibliography selection and not on systematic analysis. Therefore, we performed a systematic review of the literature reporting about the level of STS, SULT1E1, CYP19A1, HSD17B1 and HSD17B2 in EC. Additional intracrine enzymes and networks (e.g., HSD17Bs other than types 1 and 2, aldo-keto reductases, progesterone and androgen metabolism) were non-systematically reviewed as well.

Molecular-targeted therapies and precision medicine for endometrial cancer

The overall survival rate of patients with early-stage endometrial cancer is relatively high; however, there are few treatment options for patients with advanced or recurrent endometrial cancer, and the prognosis of such patients remains poor. Recent progress in molecular-targeted therapies demonstrated that they have the potential to improve the long-term survival of cancer patients with appropriate biomarkers. However, the median progression-free survival of patients who received single-agent molecular-targeted therapy was <5 months, and the development of molecular-targeted therapies for endometrial cancer patients is urgently needed. This review highlights the previous efforts, including antiangiogenesis therapy, PI3K/AKT/mTOR pathway inhibitor treatment and epidermal growth factor receptor inhibitor treatment and reports on ongoing phase 2 clinical trials, including immune checkpoint inhibitor and PARP inhibitor. We also summarized the genetic background of endometrial cancer according to The Cancer Genome Atlas data and considered the theoretical background for future efforts to prolong the survival of patients with refractory endometrial cancer and for other interesting challenges.

Intracrine Regulation of Estrogen and Other Sex Steroid Levels in Endometrium and Non-gynecological Tissues; Pathology, Physiology, and Drug Discovery

Our understanding of the intracrine (or local) regulation of estrogen and other steroid synthesis and degradation expanded in the last decades, also thanks to recent technological advances in chromatography mass-spectrometry. Estrogen responsive tissues and organs are not passive receivers of the pool of steroids present in the blood but they can actively modify the intra-tissue steroid concentrations. This allows fine-tuning the exposure of responsive tissues and organs to estrogens and other steroids in order to best respond to the physiological needs of each specific organ. Deviations in such intracrine control can lead to unbalanced steroid hormone exposure and disturbances. Through a systematic bibliographic search on the expression of the intracrine enzymes in various tissues, this review gives an up-to-date view of the intracrine estrogen metabolisms, and to a lesser extent that of progestogens and androgens, in the lower female genital tract, including the physiological control of endometrial functions, receptivity, menopausal status and related pathological conditions. An overview of the intracrine regulation in extra gynecological tissues such as the lungs, gastrointestinal tract, brain, colon and bone is given. Current therapeutic approaches aimed at interfering with these metabolisms and future perspectives are discussed.

Oral Progestin Treatment for Early-Stage Endometrial Cancer: A Systematic Review and Meta-analysis

OBJECTIVE

This study aimed to evaluate the efficacy and safety of oral progestin treatment for early-stage endometrial cancer.

METHODS

We conducted a systematic review and meta-analysis of the proportions from observational studies. Original studies were selected if patients with early-stage endometrial cancer, especially those of reproductive age, were treated with oral progestin. We conducted searches on studies listed in MEDLINE, EMBASE, and Cochrane that were published through June 2014, and relevant articles were also searched. The methodological quality of the included studies was assessed using the Newcastle-Ottawa quality assessment scale. Funnel plots and metaregression analyses were used to assess bias.

RESULTS

The final sample included 25 articles involving 445 patients. Based on a random-effects model, patients achieved a disease regression rate of 82.4% (95% confidence interval [CI], 75.3%-88.7%), a relapse rate of 25.0% (95% CI, 15.8%-35.2%), a pregnancy rate of 28.8% (95% CI, 22.5%-35.5%), and a live birth rate of 19.6% (95% CI, 12.8%-27.4%). Body weight gain, liver dysfunction, and abnormal blood coagulation test results were the most common treatment-related adverse effects. Only 2 disease-related deaths were reported during the follow-up duration.

CONCLUSIONS

Based on the present systematic review and meta-analysis, oral progestin treatment is feasible and safe for patients of reproductive age.

[Fertility-sparing management of endometrial cancer and atypical hyperplasia]

The fertility sparing management of endometrial cancer and atypical hyperplasia concern women in childbearing age with stage 1, grade 1, endometrioid adenocarcinoma confined to endometrium or atypical hyperplasia (simple or complex). These pathologies affecting more frequently postmenopausal women, the number of people involved is relatively low. The main risk factor is hyperestrogenism and these patients often present a history of infertility with a desire for pregnancy. The recommendations for this conservative management are scarce and unclear. The national observatory in the gynecology and obstetrics department of Bichat hospital gives expert advice to help doctors and patients concerned. We present a type of conservative management based on the expertise of the national observatory. Rigorous pre-therapeutic assessment must first be made to avoid missing a more advanced lesion. Hormone therapy is then started to obtain complete remission. In case of remission, fast achieving pregnancy is advised, and the use of assisted reproductive therapy is possible if necessary. Monitoring by hysteroscopy and histological examination is essential during the treatment. Hysterectomy is the last time the conservative management. It is motivated by the risk of recurrence and progression. The probability of remission after conservative treatment is estimated at 78.0 % at 12 months, the probability of recurrence at 29.2 % at 24 months, and the risk of progression at 15 % (stage 1A with myometrial invasion or more on the hysterectomy specimen). In terms of fertility, 32 % of women get at least one pregnancy.

Histologic effects of medroxyprogesterone acetate on endometrioid endometrial adenocarcinoma: a Gynecologic Oncology Group study

Progestins have been used in the treatment of recurrent endometrial adenocarcinoma for almost 50 yr. Some endometrial carcinomas respond to hormonal therapy, but the mechanism of action remains incompletely known. We wished to determine the efficacy of progestins to induce a histologic response in endometrioid carcinomas and explore its effects on histologic and immunohistochemical measures of growth and cell death. The Gynecologic Oncology Group initiated a study of 75 women with endometrioid endometrial adenocarcinoma, 59 of whom received the progestin, medroxyprogesterone acetate for 21 to 24 d immediately before hysterectomy and had available slides. Initial biopsies and hysterectomies were hematoxylin and eosin-stained and immunostained for estrogen receptor (ER) and progesterone receptor (PR), progesterone receptor-β (PRB), Bcl-2, Ki-67, and cleaved caspase-3 (Casp3). A histologic response was defined subjectively, following which specific histologic measurements and semiquantitative scores of immunohistologic variables of initial biopsies were compared with posttreatment slides. Only 1 complete histologic response was seen, but 37 tumors (63%) had a partial histologic response. Specific histologic changes included the following: a decrease in the nuclear grade, the number of mitotic figures, nucleoli, and mean gland cellularity, and acquisition of more abundant eosinophilic cytoplasm, squamous metaplasia, and secretion. The tumors that displayed a subjectively defined histologic response following treatment differed initially from those that did not only with respect to initial nuclear grade and the mitotic index. Statistically significant differences in the specific histologic features in carcinomas of responders versus nonresponders following treatment were found only with respect to acquisition of pale eosinophilic cytoplasm and luminal secretion. More than 90% of tumors were initially ER positive and 76% were PR positive. The initial presence of ER or PR was not related to subjective histologic response. PR and PRB were significantly downregulated following progestin therapy, as were Ki-67 and Bcl-2. However, ER and Casp3 did not change significantly. Tumors that displayed a histologic response had significantly lower pretreatment levels of Ki-67. Mean Ki-67 and Bcl-2 decreases following medroxyprogesterone acetate were greater in histologic responders than nonresponders, but not decreases in ER, PR, PRB, and Casp3. The histologic response in the tumors and their stroma differed quantitatively and qualitatively from that of the adjacent benign endometrium, where decidual change accompanied luminal secretion and secretory exhaustion of glands. Three weeks of medroxyprogesterone acetate therapy induces partial histologic responses in most endometrioid adenocarcinomas. Previously suggested features of histologic response do not capture the entire spectrum of changes seen. Downregulation of ER, PR, PRB, Ki-67, and Bcl-2 occurs without a significant change in Casp3. These alterations suggest that progestins act by differentiation of neoplastic cells with diminished proliferation rather than tumor cell death. As stromal decidualization was confined to areas surrounding benign glands, a paracrine effect may be involved in complete response to progestins.

Progesterone receptor isoforms A and B: new insights into the mechanism of progesterone resistance for the treatment of endometrial carcinoma

Progesterone therapy is an effective treatment for atypical endometrial hyperplasia and early endometrial carcinoma (EC). However, progesterone resistance is the main obstacle to the success of conservative treatment in women with type I EC and remains a major clinical challenge. Studies indicate that progesterone and progesterone receptors (PRs) play a significant role in both normal and neoplastic endometria. Most EC arises in the epithelial cells of the endometrial glands, and a large body of in vitro evidence suggests that the absence or reduced expression of PR isoform B might result in the failure of progesterone treatment and lead to aberrant PRB-mediated signalling in EC cells. A recently developed in vivo knockout mouse model suggests that enhanced DNA methylation decreases the level of stromal PR isoform A and that this is also a main contributor to progesterone resistance in EC cells. The endometrial stroma within the EC might create a microenvironment that determines how epithelial-derived cancer cells respond to progesterone. This novel study opened a new avenue for research seeking to clarify the mechanisms that regulate the specific PR isoforms that are associated with the stromal cell responses to progesterone and has led to new understanding of both endometrial cell-specific and mechanical contributions of the stroma to EC development.

Estrogen biosynthesis, phase I and phase II metabolism, and action in endometrial cancer

Endometrial cancer is the most common gynecological malignancy in the developed World. Based on their histopathology, clinical manifestation, and epidemiology, the majority of endometrial cancer cases can be divided into two groups: the more prevalent type 1 which is associated with unopposed estrogen exposure; and the less common type 2, which is usually not associated with hyper-estrogenic factors. This manuscript overviews the published data on the expression of genes encoding the estrogen biosynthetic enzymes, the phase I and phase II estrogen metabolic enzymes, and the estrogen receptors in endometrial cancer, at the mRNA, protein and enzyme activity levels. The potential role of altered expression of these enzymes and receptors in cancerous versus control endometrial tissue, and the implication of estrogens in tumor initiation and promotion, are discussed. Finally, based on the published data, a model of estrogen metabolism and actions is proposed for pre-cancerous and cancerous endometrial tissue, and the role of the estrogens in the progression of endometrial cancer from endometrial hyperplasia is suggested.

Biomarkers of progestin therapy resistance and endometrial hyperplasia progression

OBJECTIVE

We sought to identify biomarkers associated with progestin therapy resistance and persistence/progression of endometrial hyperplasia.

STUDY DESIGN

We performed a nested case-control study among women with complex (n = 73) and atypical (n = 41) hyperplasia treated with oral progestin, followed up 2-6 months for persistence/progression. We evaluated index endometrial protein expression for progesterone receptor isoform A, progesterone receptor isoform B (PRB), PTEN, Pax-2, and Bcl-2. Odds ratios and 95% confidence intervals (CIs) were estimated.

RESULTS

Among women with atypical hyperplasia, high PRB expression was associated with 90% decreased risk of persistence/progression (95% CI, 0.01-0.8). High expression of progesterone receptor A and PRB suggested decreased risk of persistence/progression (odds ratio, 0.1; 95% CI, 0.02-1.0). These findings were not observed among women with complex hyperplasia. No associations were found with PTEN, Pax-2, and Bcl-2 protein expression.

CONCLUSION

PRB expression shows promise as a biomarker of progestin response. Further research is warranted to understand how PRB expression may guide treatment decisions.

Inhibition of estrogen actions in human gynecological malignancies: new aspects of endocrine therapy for endometrial cancer and ovarian cancer

Endometrial carcinoma and possibly ovarian carcinoma are considered "estrogen-dependent tumors" in human gynecological malignancies. In endometrial carcinoma, the enzymes responsible for intratumoral estrogen metabolism and biosynthesis are different from those in human breast carcinoma, although both of them are considered "estrogen-dependent malignancies". Specific and effective endocrine treatment of endometrial carcinoma should be explored, although progestin agents have been widely used for a long time. Aromatase inhibitors, the most effective endocrine agents of breast carcinoma, retinoids, metabolites of vitamin A, and synthetic peroxisome proliferator-activated receptor (PPAR) gamma ligands, used for the treatment of insulin resistance in type II diabetes mellitus, may be the important candidates for possible endocrine treatment of endometrial carcinoma. In ovarian carcinoma, several clinical studies recently demonstrated that aromatase inhibitors had some therapeutic activity against recurrent ovarian carcinoma. However, at least at this juncture, further studies should be required to establish an aromatase inhibitor treatment as one form of endocrine therapy of ovarian carcinoma in future.

Novel hydroxysteroid (17beta) dehydrogenase 1 inhibitors reverse estrogen-induced endometrial hyperplasia in transgenic mice

Local estrogen production plays a key role in proliferative endometrial disorders, such as endometrial hyperplasia and cancer. Hydroxysteroid (17beta) dehydrogenase 1 (HSD17B1) is an enzyme that catalyzes with high efficiency the conversion of weakly active estrone into highly potent estradiol. Here we report that female transgenic mice expressing human HSD17B1 invariably develop endometrial hyperplasia in adulthood. These mice also fail to ovulate and have enhanced peripheral conversion of estrone into estradiol in a variety of target tissues, including the uterus. As in humans, endometrial hyperplasia in HSD17B1 transgenic female mice was reversible on ovulation induction, which triggers a rise in circulating progesterone levels, and in response to exogenous progestins. Strikingly, a treatment with an HSD17B1 inhibitor failed to restore ovulation yet completely reversed the hyperplastic morphology of epithelial cells in the glandular compartment, although less so in the luminal epithelium. The data indicate that human HSD17B1 expression enhances endometrial estrogen production, and consequently, estrogen-dependent proliferation. Therefore, HSD17B1 is a promising new therapeutic target in the management of estrogen-dependent endometrial diseases.

Recent advances on the action of estrogens and progestogens in normal and pathological human endometrium

Hormonal control in the development of the normal endometrium is of the utmost importance. It is well established that the two main hormones involved in this process are estradiol and progesterone, which are also implicated in the pathological conditions concerning endometriosis and endometrial carcinoma. There are two types of endometrial carcinoma: type I which represents 80%–90% is hormone-dependent, whereas the remainder is type II and is hormone-independent. The endometrial tissue contains all the enzymatic systems in the formation and transformation of the various hormones, including aromatases, sulfatases, sulfotransferases, hydroxysteroid dehydrogenases, hydroxylases, and glucuronidases. It is interesting to note that increased sulfatase activity is correlated with severity of endometriosis. An increased sulfatase/sulfotransferase ratio represents a poor prognosis in patients with endometrial carcinoma. Treatment with hormone replacement therapy (estrogens+progestogens), as well as with tibolone, is most effective in protecting this tissue by climacteric alterations, owing to the significant decrease of ovarian hormones. In conclusion, enzymatic control can open appealing perspectives to protect this organ from possible pathological alterations.

Aberrant pre-receptor regulation of estrogen and progesterone action in endometrial cancer

Endometrial cancer is related to estrogen stimulation not opposed by progesterone. We have examined expression of the pre-receptor regulatory enzymes aromatase, 17beta-hydroxysteroid dehydrogenases (17beta-HSDs), 20alpha-hydroxysteroid dehydrogenases (20alpha-HSDs), sulfatase and sulfotransferase, and estrogen (ERs) and progesterone (PRs) receptors in samples of endometrial cancer and adjacent normal endometrium. No significant gene up-regulation was seen, although aromatase, AKR1C3, a 17beta-HSD and 20alpha-HSD, and AKR1C1, the major 20alpha-HSD, were up-regulated in 50% of samples. Significant down-regulation was seen for 17beta-HSD types 1 and 7, sulfotransferase, ERalpha, ERbeta, PR-AB. Western blotting revealed higher levels of AKR1C3 and PR-B and lower levels of ERalpha in cancerous endometrium, and immunohistochemistry confirmed expression of AKR1C3, PR-B and ERalpha at the cellular level. Up-regulation of aromatase in concert with AKR1C3 can lead to increased levels of estradiol, which acts via ERalpha. Up-regulation of AKR1C1 and AKR1C3 can result in lower levels of the protective progesterone, which acts mainly via PR-B.

Biological roles of estrogen and progesterone in human endometrial carcinoma--new developments in potential endocrine therapy for endometrial cancer

Endometrial carcinoma is one of the most common female pelvic malignancies. It is well known that uterine endometrial cell proliferation is under the control of both estrogen and progesterone. In this review, results of the recent studies on the biosynthesis and action of estrogen and progestin in normal endometrium and its disorders will be summarized and the new aspects of hormonal therapies in the patients with endometrial carcinoma will be discussed including its future prospectives. We reported that the enzymes responsible for intratumoral estrogen metabolism and biosynthesis are markedly different between human breast and endometrial carcinoma, although both of them are considered "estrogen-dependent malignancies". In addition, the biological significance of Progesterone receptor (PR) isoforms is considered to differ between endometrial and breast carcinomas. Clinical data concerning Hormone replacement therapy (HRT) and estrogen-dependent cancer risk also support these findings. These basic and clinical findings help to understand the biology and provide the new knowledge for prevention, diagnosis and treatment of human endomerial carcinoma. Specific endocrine treatment of endometrial carcinoma should be explored in future, although aromatase inhibitors are the most effective endocrine treatments of estrogen-responsive breast carcinoma. Retinoid, metabolities of vitamin A, and synthetic peroxisome proliferator-activated receptor (PPAR) gamma ligands, which have been used for the treatment of insulin resistance in type II diabetes mellitus, may be the important candidates as drugs not only for prevention but also for possible endocrine treatment of endometrial carcinoma.

Expression of Organic Cation Transporter SLC22A16 in Human Endometria

SLC22A16 is one of newly isolated organic cation transporters, which is responsible for uptake and transport of adriamycin into cells. Adriamycin is one of the key drugs for treatment of endometrial cancer. Therefore, we examined expression of SLC22A16 in human endometrium and its disorders. Protein and mRNA expression levels of SLC22A16 were examined in 124 endometrial cancer specimens, 25 normal endometrial tissue samples (15 in proliferative phase, 10 in secretory phase), and 7 endometrial cancer cell lines using immunohistochemical analysis and reverse transcription-polymerase chain reaction. Changes in SLC22A16 mRNA expression level after progesterone exposure were also examined. Immunohistochemical analysis showed that SLC22A16 protein was highly expressed in endometrium during the normal secretory phase, but its level was significantly reduced in the proliferative phase. SLC22A16 protein was detected in 59 of 124 (48%) endometrial cancer specimens and 3 of 7 (43%) endometrial cancer cell lines. The mRNA levels measured by quantitative reverse transcription-polymerase chain reaction were comparable with levels of protein expression. Furthermore, SLC22A16 mRNA levels were increased in endometrial cancer cell lines in the presence of progesterone. In conclusion, SLC22A16 is expressed in various endometrial tissues. Its expression level is high during the secretory phase and may be regulated by progesterone. Our findings also suggest that it may be possible to use progestins to increase the response of endometrioid endometrial carcinoma with SLC22A16 expression to adriamycin-based chemotherapeutic regimens.

Progesterone receptor isoforms as a prognostic marker in human endometrial carcinoma

The possible role of specific progesterone receptor (PR) isoforms (PRA and PRB) as predictive factors in endometrial carcinoma is unclear. The present study was undertaken to evaluate the clinical significance of intratumoral PR isoform status in patients with endometrioid endometrial carcinoma. We studied 103 cases of endometrioid endometrial carcinoma using immunohistochemistry. We correlated the findings with various clinicopathological parameters of the patients. PRA and PRB immunoreactivity was detected in 51/103 (48.5%) and 79/103 (76.7%) of carcinoma cases, respectively. A significant positive correlation was detected between the status of PRB immunoreactivity and the amount of PRB mRNA by real-time reverse transcription-polymerase chain reaction (P = 0.012). PR isoform expression was significantly lower in the cases with higher histological grade (P = 0.0001 and P = 0.002, for PRA and PRB, respectively). Cases that were negative for either one or both PR isoforms were significantly associated with shorter disease-free and overall survival of the patients. The absence of either one or both of these two PR isoforms was detected in all nine patients who died (100.0%), whereas the absence of these immunoreactivities was detected only in 43 of 94 (45.7%) patients who had lived during the same period. In addition, multivariate analysis demonstrated that an absence of PRA immunoreactivity was an independent risk factor in disease-free survival of the patients (P = 0.0258). The results of our study demonstrated that loss or absence of PR isoform expression determined by immunohistochemistry could become an important prognostic indicator in patients with endometrioid endometrial carcinoma.

Conserving fertility in the management of gynaecological cancers

The quality of cancer treatment is judged by both morbidity and mortality. Patients benefit if morbidity is reduced without compromising mortality. This applies particularly for women who develop gynaecological malignancy during their childbearing years where curative treatment also renders them infertile. This study reviews the increasing role of fertility-sparing surgery in such women. A literature search was undertaken using PubMed, entering the terms endometrial cancer, cervical cancer and ovarian cancer in conjunction with the terms fertility and fertility sparing. Each relevant identified paper was reviewed, references checked and results collated to provide an evidence-based summary of fertility-sparing treatments for gynaecological malignancy. Fertility-sparing surgery is appropriate in many circumstances, and all doctors who advise young women with gynaecological malignancy should be aware of these possibilities. However, data are relatively sparse in many situations, and careful counselling and balanced guidance are essential if patients are to understand the full implications of their choices.

Expression analysis of estrogen-metabolizing enzymes in human endometrial cancer

Estrogen-dependent endometrial cancer is related to unopposed and prolonged estrogen stimulation. We examined the expression of estrogen-metabolizing enzymes in correlation with the ERalpha and ERbeta estrogen receptors in human endometrial Ishikawa adenocarcinoma cells and in endometrial cancer specimens and adjacent normal endometrium from the same patients. Real-time PCR analysis revealed that both estrogen receptors and selected estrogen-metabolizing enzymes were expressed in the Ishikawa cells and in endometrial tissue. We detected higher expression of ERalpha than ERbeta, higher expression of sulfatase than sulfotransferase and low expression of aromatase in the Ishikawa cells and the tissue, as well as higher levels of type 2 17beta-hydroxysteroid dehydrogenase (17beta-HSD) in normal and diseased tissue than in the Ishikawa cells. When we compared the expression in endometrial cancer samples and in the adjacent normal endometrium, ERalpha and ERbeta, sulfatase and sulfotransferase were seen to be downregulated in the majority of the cancerous tissue specimens.

AKR1C1 and AKR1C3 may determine progesterone and estrogen ratios in endometrial cancer

Endometrial cancer is the most common malignancy of the female genital tract. Its incidence correlates with prolonged estrogen stimulation unopposed by progesterone or synthetic progestins. Estrogen and progestin action is regulated at the pre-receptor level, by interconversion of active hormones (estradiol (E2), progesterone (P)) with their inactive counterparts (estrone (E1), 20alpha-hydroxyprogesterone (20alpha-OHP)) in target tissues. Expression of enzymes that control the ratio of E2 and P may thus play role in the disease process. We first confirmed that AKR1C1 (human 20alpha-hydroxysteroid dehydrogenase) in a cellular context inactivates P by forming 20alpha-OHP but does not catalyze the reverse reaction. We next examined the expression of AKR1C1 and AKR1C3 (type 5 17beta-hydroxysteroid dehydrogenase) in 16 paired specimens of endometrial cancer and adjacent normal endometrium. Quantification by isoform specific real-time PCR revealed higher expression of AKR1C1 in nine specimens and higher expression of AKR1C3 in four specimens of endometrial cancer. Importantly, upregulation of both enzymes in the same specimen was observed. Since AKR1C1 inactivates P its elevated expression in diseased endometrium may contribute to diminished protection by P, while elevated expression of AKR1C3 which forms E2 in vivo, may contribute to the enhanced estrogen action. It is suggested that the expression of AKR1C1 and AKR1C3 in endometrial cancer will govern the ratio of P:E2.

The role of hormones for the treatment of endometrial hyperplasia and endometrial cancer

PURPOSE OF REVIEW

Hormone therapy has been palliative for advanced/ recurrent endometrial cancer. High remission rates are seen in well-selected stage I, grade 1 endometrial cancer of young women using hormone therapy (usually progestins) as fertility-preserving treatment. Many other hormones, such as gonadotropin-releasing hormone analogs (GnRHa), selective estrogen receptor modulators, aromatase inhibitors, intrauterine progestins, and others are potential modalities. This review updates the recent publications in this area.

RECENT FINDINGS

Two reports investigating different scheduling of tamoxifen and progestins indicated that tamoxifen may be a valuable adjunct to progestin therapy. GnRHa has been used adjunctively to tamoxifen as second-line hormone therapy for fertility sparing after progestin failed. Aromatase inhibitors have shown their potential in treating endometrial cancer and endometrial hyperplasia as single agent or in combination with progestins. Intrauterine progestins seem efficacious in treating endometrial hyperplasia; its applications on endometrial cancer patients, however, have been limited to postmenopausal women with poor surgical risk.

SUMMARY

Translational research based on molecular mechanisms is mandatory to a more appropriate utilization of hormone therapy. The role of dose, scheduling, route of administration of progestins as well as the addition of other hormonal agents should be further explored by well designed randomized controlled trials.

Difference in progesterone-receptor isoforms ratio between early and late first-trimester human trophoblast is associated with differential cell invasion and matrix metalloproteinase 2 expression

The expression profile of the progesterone-receptor isoforms and progesterone regulation of matrix metalloproteinase 2 (MMP2) were investigated in early and late first-trimester trophoblast cells. Human trophoblast cells were obtained from legal abortions (6-12 wk of gestation). Purity of 95-98% was verified using immunohistochemistry with specific antibodies. Evaluation of cell count was performed with XTT Reagent kit, and invasion was tested using Matrigel invasion assay. Zymography was used to detect proteolytic activity, and Western blot immunoassay was used to study protein concentration. Gene expression of PGRB, PGR, and MMP2 was studied using reverse transcription-polymerase chain reaction with the housekeeping gene GAPDH used for normalization. Promoter activity was determined using luciferase reporter assay. Differential progesterone-receptor profile was documented with the dominance of PGRB in early trophoblast and the dominance of PGRA in late trophoblast. This differential profile is compatible with the inverse effect of progesterone on the two cell populations, decreasing invasion and gelatinase expression in the early first-trimester trophoblast and increasing invasion and gelatinase expression in the late first-trimester trophoblast. A decrease in MMP2 promoter activity in early trophoblast cells exposed to progesterone suggests that MMP2 expression is regulated by progesterone at the transcriptional level as well. Early trophoblast cells transfected with expressing vector for PGR encoding PGRA revealed less MMP2 activity and reversal of its response to progesterone similar to the effect observed in late trophoblast cells.