Hormone prevention strategies for breast, endometrial and ovarian cancers

In vitro chemo-preventive efficacy of synthetic progestin Norethindrone in human epithelial ovarian cancer

Progestin-only based oral contraceptives are majorly used as 'minipill' to prevent unintended pregnancy and treat conditions like polycystic ovary syndrome, hirsutism, and acne. However, the dearth of literature has constrained our comprehension of the exogenous progestin in relation to ovarian cancer progression. Therefore, the aim of the present study was to evaluate the chemo-preventive potential of synthetic progestin Norethindrone (NET) in epithelial ovarian cancer in vitro. Briefly, SKOV3 cells were treated with 1, 10 and 100 µM concentrations of NET for seven days period. The assays for cell viability, wound-healing, cell cycle progression, detection of reactive oxygen species (ROS) and apoptosis were executed to illustrate the protective role of NET. To further clarify the underlying process, quantitative analysis of mRNA levels of oncogenes linked to angiogenesis, inflammation, proliferation, and metastasis (VEGF, HIF-1α, COX-2, and PGRMC1) and tumour suppressor (TP53) genes was conducted. Our study revealed that NET treatment significantly reduced SKOV3 cell growth by inducing cell cycle arrest at G2/M phase, elevating ROS levels, triggering cell death via apoptosis and necrosis, and inhibiting cell migration in a dose-dependent manner. Notably, NET also upregulated TP53 expression while concurrently downregulating VEGF, HIF-1α, COX-2, and PGRMC1 expression. Our results demonstrated that the chemo-preventive effect of Norethindrone may originate from the interaction of genes which exert a protective effect against ovarian carcinogenesis. The current findings also support further investigation, which may lead to changes in prescription practices or health-related advice for women.

Germline BRCA mutation carriers are more likely to undergo cytoreductive surgery for relapsed, platinum sensitive, ovarian cancer

OBJECTIVE

BRCA mutations have been associated with improved outcomes in ovarian cancer patients. This study's objective was to compare the secondary cytoreduction surgery (SCS) rates among ovarian cancer patients by BRCA mutation status.

METHODS

The study was retrospective and included platinum sensitive recurrent high grade serous ovarian cancer patients from one Canadian center and two Israeli centers from January 1999 to December 2018. Demographic and genetic data, tumor characteristics, patterns of recurrence and surgical and medical treatments were obtained from electronic charts. Patients were grouped according to BRCA mutation status. Logistic regression analyses were used to explore potential prognostic factors of secondary cytoreduction.

RESULTS

147 patients were enrolled, including 97 from Canada and 50 from Israel. Forty-seven patients (32%) had a BRCA mutation, including 39 (26.5%) germline mutations and 8 (5.5%) somatic mutations. Thirty-one patients (21.1%) underwent SCS. The rate of SCS was 33.3% among the germline BRCA mutation carriers and 15.7% among patients without germline BRCA mutation (p = 0.026). Predictors of secondary cytoreduction included germline BRCA mutation (OR = 2.5, p = 0.03), time to recurrence (OR = 1.004 per month, p < 0.001), absence of lymphatic recurrence (OR = 3.08, p = 0.013), three or fewer lesions at recurrence (OR = 36.74, p < 0.001) and absence of ascites (OR = 9.1, p = 0.034). After adjusting for the number of lesions at recurrence, no other variable remained a significant predictor.

CONCLUSION

Germline BRCA mutation carriers are more likely to undergo secondary cytoreduction. This may be mediated in part by lower volume disease at recurrence. This observation should be considered when planning surveillance for these patients after first-line treatment.

Methylation of ERβ 5'-untranslated region attenuates its inhibitory effect on ERα gene transcription and promotes the initiation and progression of papillary thyroid cancer

Normal thyroid tissue displays a prevalent expression of ERβ than ERα, which drastically turns upside down in the initiation and progression of papillary thyroid cancer (PTC). The underlying molecular mechanism of this phenomenon remains unclear. Here, we demonstrated that ERα and ERβ were coexpressed in human thyroid tissues and cells. ERα mRNA (A-1) and ERβ mRNA (0N-1), transcribed from Promoter A of ERα gene and Promoter 0N of ERβ gene, respectively, were the major mRNA isoforms which mainly contributed to total ERα mRNA and total ERβ mRNA in human thyroid-derived cell lines and tissues. The expression levels of ERα mRNA (A-1) and total ERα mRNA were gradually increased, and those of ERβ mRNA (0N-1) and total ERβ mRNA were decreased by degree in the initiation and progression of PTC. No aberrant DNA methylation of ERα 5'-untranslated region was involved in its up-regulation; however, aberrant DNA methylation in Promoter 0N and Exon 0N of ERβ gene was found to be involved in its down-regulation in the initiation and progression of PTC. ERβ can repress ERα gene transcription via recruitment of NCoR and displacement of RNA polymerase II at the Sp1 site in ERα Promoter A-specific region in thyroid-derived cells. It is suggested that DNA methylation of CpG islands in Promoter 0N and Exon 0N of ERβ gene leads to a decreased ERβ gene expression, which attenuates its inhibitory effect on ERα gene transcription and results in an increased ERα gene expression, cell proliferation, initiation, and progression of PTC.

Comprehensive analysis of regulation of DNA methyltransferase isoforms in human breast tumors

Significant reprogramming of epigenome is widely described during pathogenesis of breast cancer. Transformation of normal cell to hyperplastic cell and to neoplastic phenotype is associated with aberrant DNA (de)methylation, which, through promoter and enhancer methylation changes, activates oncogenes and silence tumor suppressor genes in variety of tumors including breast. DNA methylation, one of the major epigenetic mechanisms is catalyzed by evolutionarily conserved isoforms namely, DNMT1, DNMT3A and DNMT3B in humans. Over the years, studies have demonstrated intricate and complex regulation of DNMT isoforms at transcriptional, translational and post-translational levels. The recent findings of allosteric regulation of DNMT isoforms and regulation by other interacting chromatin modifying proteins emphasizes functional integrity and their contribution for the development of breast cancer and progression. DNMT isoforms are regulated by several intrinsic and extrinsic parameters. In the present review, we have extensively performed bioinformatics analysis of expression of DNMT isoforms along with their transcriptional and post-transcriptional regulators such as transcription factors, interacting proteins, hormones, cytokines and dietary elements along with their significance during pathogenesis of breast tumors. Our review manuscript provides a comprehensive understanding of key factors regulating DNMT isoforms in breast tumor pathology and documents unsolved issues.

Chemotherapy Toxicity in BRCA Mutation Carriers Undergoing First-Line Platinum-Based Chemotherapy

OBJECTIVE

BRCA mutations are the most frequent mutations causing homologous recombination defects in epithelial ovarian cancers (EOC). Germline mutation carriers are heterozygous for the mutation and harbor one defective allele in all cells. This has been hypothesized to cause increased susceptibility to DNA damage in healthy cells as well as neoplastic ones. Our objective was to assess chemotherapy-associated toxicities in patients with epithelial ovarian cancer with and without a germline BRCA mutation.

MATEIALS AND METHODS

A retrospective cohort study of patients with EOC receiving first-line platinum-based chemotherapy at a single center between 2006 and 2016. Indices of chemotoxicity, including blood counts, transfusion requirements, granulocyte colony-stimulating factor (gCSF) prescriptions, episodes of febrile neutropenia, and treatment delays were compared for BRCA mutation carriers and noncarriers.

RESULTS

A total of 90 women met the inclusion criteria, including 31 BRCA mutation carriers (34%) and 59 noncarriers (66%). Mean hemoglobin, neutrophil count, and platelet counts during treatment were comparable for the two patient groups. There was a trend toward a higher frequency of hematological events in BRCA mutation carriers (neutropenia <1500 per mL: 6% vs. 0%, p = .12; thrombocytopenia <100,000 per mL: 23% vs. 9%, p = .07), but these differences were not statistically significant. Similarly, no significant differences were found in surrogates of bone marrow toxicity such as blood transfusions, use of gCSF, episodes of febrile neutropenia, or treatment delays.

CONCLUSION

BRCA mutation carriers and noncarriers receiving first-line platinum-based chemotherapy for EOC have similar hematologic toxicity profiles. Clinicians treating these patients can be reassured that chemotherapy dosing or schedule do not require adjustment in patients carrying BRCA mutations.

IMPLICATIONS FOR PRACTICE

Patients with ovarian cancer carrying BRCA mutations are more likely to have serous tumors and present with higher CA125 levels. Germline BRCA mutation status is not associated with increased frequency of adverse hematologic events among patients with ovarian cancer being treated with first-line platinum-based chemotherapy. Germline BRCA mutations are also not associated with more treatment delays or a lower number of courses completed in this patient population. These findings should reassure practitioners engaged in care for patients with ovarian cancer that BRCA mutation status most likely will not affect chemotherapy dosing or schedule.

Trends in incidence of uterine cancer in Songkhla, Southern Thailand

Objective

To define the present incidence of uterine cancer and the trends of incidence in the future. Additional, subgroup analysis in religion and socio-demographic factors will be analyzed.

Methods

The data of uterine cancer from The Songkhla Cancer Registry between; 1989 and 2016, was extracted. The population denominators of Songkhla Province were referred from the information of the population censuses surveyed by the National Statistical Office. The incidence was estimate by; the age specific rate, and analyzed in trend incidence using Jointpoint and Age-period-cohort; APC regression models and trend projection in 2017–2030 using by Jointpoint, the NordPred and APC model. The comparison of incidence according to habitat and religion were unpaired t-test.

Results

The incidence of uterine cancer in Songkhla Province increased from 1.5, to 5.3 per 100,000 women-years in 2016, and 8 per 100,000 women-years in 2030. The incidence was more in urban areas and in Buddhists.

Conclusion

The incidence of uterine cancer is increasing. The policy, which promotes protective factors and control risk factors, would decrease incidence of endometrial cancer, and other estrogen dependent cancers additional to chronic diseases from the cardiovascular system.

Isolation, synthesis, and cytotoxicity evaluation of two impurities in nomegestrol acetate

Nomegestrol acetate (NOMAc) is a synthetic progesterone analog and classified as a fourth-generation progestin. It has been approved in many countries for oral contraception, hormonal replacement therapy (HRT), and treatment of various gynecological disorders. There are several synthetic routes reported for the synthesis of NOMAc and they all share the very similar last three to five steps toward the conversion of 6-methylene to 6-methyl-6,7-unsaturated structure. Therefore the final product from different processing routes may have similar impurity profiles. In the analysis of NOMAc, we identified two impurities, impurity A (listed in EP 8.0) and impurity B (not specified in EP 8.0). Both impurities were further confirmed by synthesis. In addition, both impurities and NOMAc were evaluated for their in vitro cytotoxicities against L02 liver cells, mesenchymal stem cells, MCF-7 breast cancer cells, and C33A cervical cancer cells. These three analogs are not cytotoxic to the four cell lines at low concentrations (<20 μM). NOMAc and impurity A showed cytotoxicity to L02, MCF-7, and C33A cells at high concentrations, while impurity B did not show significant cytotoxicity to any of the cell lines tested.

A role for G-protein coupled estrogen receptor (GPER) in estrogen-induced carcinogenesis: Dysregulated glandular homeostasis, survival and metastasis

Mechanisms of carcinogenesis by estrogen center on its mitogenic and genotoxic potential on tumor target cells. These models suggest that estrogen receptor (ER) signaling promotes expansion of the transformed population and that subsequent accumulation of somatic mutations that drive cancer progression occur via metabolic activation of cathecol estrogens or by epigenetic mechanisms. Recent findings that GPER is linked to obesity, vascular pathology and immunosuppression, key events in the development of metabolic syndrome and intra-tissular estrogen synthesis, provides an alternate view of estrogen-induced carcinogenesis. Consistent with this concept, GPER is directly associated with clinicopathological indices that predict cancer progression and poor survival in breast and gynecological cancers. Moreover, GPER manifests cell biological responses and a microenvironment conducive for tumor development and cancer progression, regulating cellular responses associated with glandular homeostasis and survival, invading surrounding tissue and attracting a vascular supply. Thus, the cellular actions attributed to GPER fit well with the known molecular mechanisms of G-protein coupled receptors, GPCRs, namely, their ability to transactivate integrins and EGF receptors and alter the interaction between glandular epithelia and their extracellular environment, affecting epithelial-to-mesenchymal transition (EMT) and allowing for tumor cell survival and dissemination. This perspective reviews the molecular and cellular responses manifested by GPER and evaluates its contribution to female reproductive cancers as diseases that progress as a result of dysregulated glandular homeostasis resulting in chronic inflammation and metastasis. This review is organized in sections as follows: I) a brief synopsis of the current state of knowledge regarding estrogen-induced carcinogenesis, II) a review of evidence from clinical and animal-based studies that support a role for GPER in cancer progression, and III) a mechanistic framework describing how GPER-mediated estrogen action may influence the tumor and its microenvironment.

Clinical significance of the estrogen-modifying enzymes steroid sulfatase and estrogen sulfotransferase in epithelial ovarian cancer

17β-estradiol (E2) can contribute to the progression of epithelial ovarian cancer (EOC). Although the majority of patients with EOC are postmenopausal woman, when de novo estrogen production in the ovary has ceased, ovarian cancer cells remain exposed to estrogens synthesized locally in the cancer cells from inactive sulfonated steroid hormone precursors-such as estrone sulfate taken up from the circulation via the sulfatase pathway. An abundance of the estrogen-modifying enzymes, including estrogen-activating steroid sulfatase (STS) and estrogen-inactivating estrogen-sulfotransferase (SULT1E1), is important for providing active estrogen to EOC cells. Therefore, the present study determined the levels of SULT1E1, STS and estrogen receptor α (ERα) protein in paraffin-embedded specimens from 206 patients with Federation of Gynecology and Obstetrics stage II–IV EOC treated with debulking surgery and standard platinum-based adjuvant chemotherapy. The levels of STS, SULT1E1 and ERα were assessed by automated quantitative microscopy-based image analysis subsequent to immunohistochemical staining. Significantly higher SULT1E1 levels were observed in better differentiated EOC tumors compared to grade 3 EOC tumors (P=0.001). STS and SULT1E1 levels were positively associated with ERα abundance (P<0.001 and P=0.001, respectively). In advanced stage high-grade serous EOC (HGSOC; n=132), the most frequent and lethal type of ovarian cancer, SULT1E1 expression was significantly associated with a better overall survival rate (hazard ratio 0.66, 95% confidence interval, 0.45–0.94; P=0.005). These results highlight the importance of SULT1E1-mediated estrogen inactivation in EOC, particularly HGSOC. Therefore, targeting the sulfatase pathway is a potential endocrine therapeutic intervention for certain patients with estrogen-responsive EOC.

Dysregulation of Aromatase in Breast, Endometrial, and Ovarian Cancers: An Overview of Therapeutic Strategies

Aromatase is the rate-limiting enzyme in the biosynthesis of estrogens, which play crucial roles on a spectrum of developmental and physiological processes. The biological actions of estrogens are classically mediated by binding to two estrogen receptors (ERs), ERα and ERβ. Encoded by the cytochrome P450, family 19, subfamily A, polypeptide 1 (CYP19A1) gene, aromatase is expressed in a wide variety of tissues, as well as benign and malignant tumors, and is regulated in a pathway- and tissue-specific manner. Overexpression of aromatase, leading to elevated systemic levels of estrogen, is unequivocally linked to the pathogenesis and growth of a number malignancies, including breast, endometrium, and ovarian cancers. Aromatase inhibitors (AIs) are routinely used to treat estrogen-dependent breast cancers in postmenopausal women; however, their roles in endometrial and ovarian cancers remain obscure. While AI therapy is effective in hormone sensitive cancers, they diminish estrogen production throughout the body and, thus, generate undesirable side effects. Despite the effectiveness of AI therapy, resistance to endocrine therapy remains a major concern and is the leading cause of cancer death. Considerable advances, toward mitigating these issues, have evolved in conjunction with a number of histone deacetylase (HDAC) inhibitors for countering an assortment of diseases and cancers, including the aforesaid malignancies. HDACs are a family of enzymes that are frequently dysregulated in human tumors. This chapter will discuss the current understanding of aberrant regulation and expression of aromatase in breast, endometrial, and ovarian cancers, and potential therapeutic strategies for prevention and treatment of these life-threatening diseases.

The wedelolactone derivative inhibits estrogen receptor-mediated breast, endometrial, and ovarian cancer cells growth

Estrogen and estrogen receptor (ER)-mediated signaling pathways play important roles in the etiology and progression of human breast, endometrial, and ovarian cancers. Attenuating ER activities by natural products and their derivatives is a relatively practical strategy to control and reduce breast, endometrial, and ovarian cancer risk. Here, we found 3-butoxy-1,8,9-trihydroxy-6H-benzofuro[3,2-c]benzopyran-6-one (BTB), a new derivative of wedelolactone, could effectively inhibit the 17-estradiol (E2)-induced ER transactivation and suppress the growth of breast cancer as well as endometrial and ovarian cancer cells. Our results indicate that 2.5 μM BTB effectively suppresses ER-positive, but not ER-negative, breast, endometrial, and ovarian cancer cells. Furthermore, our data indicate that BTB can modulate ER transactivation and suppress the expression of E2-mediated ER target genes (Cyclin D1, E2F1, and TERT) in the ER-positive MCF-7, Ishikawa, and SKOV-3 cells. Importantly, this BTB mediated inhibition of ER activity is selective since BTB does not suppress the activities of other nuclear receptors, including glucocorticoid receptor and progesterone receptor, suggesting that BTB functions as a selective ER signaling inhibitor with the potential to treat breast, endometrial, and ovarian cancers.

Cancer risk management decision making for BRCA+ women

Women with pathogenic BRCA genetic mutations face high risks for cancer development. Estimates vary among mutation carriers, with lifetime risks ranging from 41% to 90% for breast cancer and 8% to 62% for ovarian cancer. Cancer risk management options for BRCA mutation positive (BRCA+) women have life-altering implications. This qualitative, phenomenological study explored the experience of cancer risk management decision making for women who are unaffected carriers of a BRCA mutation (previvors). Fifteen previvors recruited from Facing Our Risk of Cancer Empowered (FORCE), an online informational and support group, were interviewed. Findings consisted of four major themes: the early previvor experience, intense emotional upheaval; the decisional journey, navigating a personal plan for survival; lack of knowledge and experience among health care providers; and support is essential. Findings highlight the different decisional perspectives of previvors based on age and individual factors and the need for increased competence among health care providers.

Oral contraceptive and reproductive risk factors for ovarian cancer within sisters in the breast cancer family registry

BACKGROUND

Oral contraceptive use has been consistently associated with a reduced risk of ovarian cancer in unrelated, average risk women; however little data exist on whether this benefit extends to higher risk women from cancer families. To examine this, we conducted family-based analyses using the Breast Cancer Family Registry.

METHODS

We used generalised estimating equations to obtain the population average effect across all families (n=389 cases, n=5643 controls) and conditional logistic regression to examine within-family differences in a subset with at least two sisters discordant on ovarian cancer status (n=109 cases, n=149 unaffected sister controls).

RESULTS

In the multivariable generalised estimating equation model there was a reduced risk of ovarian cancer for ever use of oral contraceptives compared with never use (OR=0.58, 95% CI: 0.37, 0.91), and in the conditional logistic model there was a similar inverse association; however, it was not statistically significant (OR=0.52, 95% CI: 0.23, 1.17). We examined this association by BRCA1/2 status and observed a statistically significant reduced risk in the non-carriers only.

CONCLUSION

We observed a decreased risk of ovarian cancer with oral contraceptive use supporting that this association observed in unrelated women extends to related women at higher risk.

Hereditary breast/ovarian cancer syndrome: a primer for obstetricians/gynecologists

An understanding of the diagnosis and clinical management of hereditary breast and ovarian cancer syndrome (HBOC) is essential for obstetricians/gynecologists. This article provides practical information regarding collecting a family history, cancer risk assessment and genetic testing, BRCA-associated cancer prognosis and treatment, screening recommendations, and prevention strategies. Through appropriate cancer risk assessment, women with BRCA1/2 mutations can be identified, and screening and prevention strategies can be used before a diagnosis of cancer occurs. Women's health providers with a strong working knowledge of HBOC are able to improve the quality of care for women and families impacted by BRCA1/2 mutations.

Expression of estrogen receptors (α, β), cyclooxygenase-2 and aromatase in normal endometrium and endometrioid cancer of uterus

PURPOSE

Endometrial cancer (EC) is one of the most common malignancies of the female genital tract, but the etiology, especially its metabolism is still investigated. The aim of this study was to evaluate the presence and relative expression of Estrogen Receptors (α, β), Cyclooxygenase-2 and Aromatase in both endometrial cancer and normal mucosa.

MATERIAL/METHODS

Two groups of women were selected for the study: 1) patients with endometrioid endometrial cancer (FIGO I; G1 - G3) (n=35) and 2) subjects with normal endometrial tissue (control group, n=29). The expression of Estrogen Receptors (ERα, β), Cyclooxygenase-2 (COX-2), Aromatase were estimated by Western blot analysis. Furthermore, the associations between FIGO classification (stage: Ia, Ib), tumor grade (G) and expression of ERα, β, COX-2, aromatase proteins were evaluated. Overall and disease-free survival curves were generated according to the Kaplan-Meier method. Median follow-up time of the patients examined in this study was 39 months.

RESULTS

The relative expression of each examined protein was markedly higher in the endometrial cancer tissue as compared to the healthy endometrium. The trends towards greater expression along with a tumor progression was noticed (FIGO stage: Ia vs. Ib). Analysis of endometrial cancer risk factors and their influence on survival curves showed only an inverse significant correlations between obesity (BMI: 36.2; n=21) and disease-free survival in EC group (p=0.00872), but there was no significant association between obesity and overall survival (p=0.358).

CONCLUSIONS

Endometrioid endometrial cancer shows relatively higher expression of either ER, COX-2 and aromatase comparing to healthy mucosa, suggesting their involvement in tumor development and progression.

Anticancer steroids: linking natural and semi-synthetic compounds

Steroids, a widespread class of natural organic compounds occurring in animals, plants and fungi, have shown great therapeutic value for a broad array of pathologies. The present overview is focused on the anticancer activity of steroids, which is very representative of a rich structural molecular diversity and ability to interact with various biological targets and pathways. This review encompasses the most relevant discoveries on steroid anticancer drugs and leads through the last decade and comprises 668 references.

Active allies: hormones, stem cells and the niche in adult mammopoiesis

Adult stem cells are recruited in response to specific physiological demands to regenerate, repair or maintain essential cellular components of tissues, while preserving self-renewal capacity. Signals that activate adult stem cells are not simply cell autonomous and stem cells are part of a larger dynamic framework, the stem cell 'niche', which integrates systemic and local cues to sustain stem cell functionality. The mammary stem cell niche responds readily to hormonal stimuli, generating pertinent signals that activate stem cells, culminating in stem cell expansion and tissue growth. We review here current knowledge of the mammary stem cell niche with attention to the potent stimulation rendered by ovarian hormones, relevant cellular and molecular players, and the implication of a deregulated niche, for breast cancer risk.

Hybrid flavan-chalcones, aromatase and lipoxygenase inhibitors, from Desmos cochinchinensis

Hybrid flavan-chalcones, desmosflavans A (1) and B (2), together with three known compounds, cardamonin (3), pinocembrin (4) and chrysin (5), were isolated from leaves of Desmos cochinchinensis. Cardamonin (3) and chrysin (5) exhibited potent antioxidant activity with 15.0 and 12.2 ORAC units. Desmosflavans A (1) and B (2), pinocembrin (4), and chrysin (5) were found to be inhibitors of aromatase with respective IC50 values of 1.8, 3.3, 0.9, and 0.8 μM. Desmosflavan A (1) inhibited lipoxygenase with the IC50 value of 4.4 μM. Desmosflavan A (1) exhibited cytotoxic activity with IC50 values of 0.29-3.75 μg/mL, while desmosflavan B (2) showed IC50 values of 1.71-27.0 μg/mL.

Diacylglycerol kinase α mediates 17-β-estradiol-induced proliferation, motility, and anchorage-independent growth of Hec-1A endometrial cancer cell line through the G protein-coupled estrogen receptor GPR30

Increased levels of endogenous and/or exogenous estrogens are one of the well known risk factors of endometrial cancer. Diacylglycerol kinases (DGKs) are a family of enzymes which phosphorylate diacylglycerol (DAG) to produce phosphatidic acid (PA), thus turning off and on DAG-mediated and PA-mediated signaling pathways, respectively. DGK α activity is stimulated by growth factors and oncogenes and is required for chemotactic, proliferative, and angiogenic signaling in vitro. Herein, using either specific siRNAs or the pharmacological inhibitor R59949, we demonstrate that DGK α activity is required for 17-β-estradiol (E2)-induced proliferation, motility, and anchorage-independent growth of Hec-1A endometrial cancer cell line. Impairment of DGK α activity also influences basal cell proliferation and growth in soft agar of Hec-1A, while it has no effects on basal cell motility. Moreover, we show that DGK α activity induced by E2, as well as its observed effects, are mediated by the G protein-coupled estrogen receptor GPR30 (GPER). These findings suggest that DGK α may be a potential target in endometrial cancer therapy.

The 'incessant menstruation' hypothesis: a mechanistic ovarian cancer model with implications for prevention

Serous, endometrioid, clear cell and mucinous histotypes are the most common epithelial ovarian cancer. Most serous cancers appear to originate from precursor lesions at the fimbriated tubal end, whereas most endometrioid and clear cell cancers seem to derive from atypical endometriosis. Data regarding hormonal factors and associated gynaecologic conditions were critically analysed with the objective of defining a carcinogenic model for sporadic epithelial ovarian cancer complying with epidemiologic and pathologic findings. Oral contraceptives and tubal ligation substantially reduce the risk of serous, endometrioid and clear cell subgroups, but have no significant effect on mucinous tumours, which probably follow a different oncogenic pathway. We hypothesize that serous, endometrioid and clear cell cancers share a common pathogenic mechanism, i.e. iron-induced oxidative stress derived from retrograde menstruation. Fimbriae floating in bloody peritoneal fluid are exposed to the action of catalytic iron and to the genotoxic effect of reactive oxygen species, generated from haemolysis of erythrocytes by pelvic macrophages. This would explain the distal site of tubal intraepithelial neoplasia. Collection of blood inside endometriomas would lead to the same type of genotoxic insult on gonadal endometrial implants. This would explain why endometriosis-associated cancers develop much more frequently in the ovary than at extragonadal sites. In women not seeking conception, bilateral salpingectomy could be advised whenever planning surgery for independent indications, thus possibly reducing cancer risk, while preserving ovarian function. The use of oral contraceptives should be favoured for prolonged periods of time, especially in women with endometriosis, a population at doubled risk of gonadal malignancy.

Role of autonomous androgen receptor signaling in prostate cancer initiation is dichotomous and depends on the oncogenic signal

The steroid hormone signaling axis is thought to play a central role in initiation and progression of many hormonally regulated epithelial tumors. It is unclear whether all cancer-initiating signals depend on an intact hormone receptor signaling machinery. To ascertain whether cell autonomous androgen receptor (AR) is essential for initiation of prostate intraepithelial neoplasia (PIN), the response of AR-null prostate epithelia to paracrine and cell autonomous oncogenic signals was assessed in vivo by using the prostate regeneration model system. Epithelial-specific loss of AR blocked paracrine FGF10-induced PIN, whereas the add back of exogenous AR restored this response. In contrast, PIN initiated by cell-autonomous, chronic-activated AKT developed independent of epithelial AR signaling. Our findings demonstrate a selective role for AR in the initiation of PIN, dependent on the signaling pathways driving tumor formation. Insights into the role of hormone receptor signaling in the initiation of epithelial tumors may help define this axis as a target for chemoprevention of carcinomas.

Nuclear Receptors: Small Molecule Sensors that Coordinate Growth, Metabolism and Reproduction

One of the largest groups of metazoan transcription factors (TFs), the Nuclear Receptor superfamily, regulates genes required for virtually all aspects of development, reproduction and metabolism. Together, these master regulators can be thought of as a fundamental operating system for metazoan life. Their most distinguishing feature is a structurally conserved domain that acts as a switch, powered by the presence of small diffusible ligands. This ligand-responsive regulation has allowed the Nuclear Receptors to help their hosts adapt to a wide variety of physiological niches and roles, making them one of the most evolutionarily successful TF families. Originally discovered as receptors for steroid hormones, the Nuclear Receptor field has grown to encompass much more than traditional endocrinology. For example, recent work has highlighted the role of Nuclear Receptors as major regulators of metabolism and biological clocks. By monitoring endogenous metabolites and absorbed xenobiotics, these receptors also coordinate rapid, system-wide responses to changing metabolic and environmental states. While many new Nuclear Receptor ligands have been discovered in the past couple of decades, approximately half of the 48 human receptors are still orphans, with a significantly higher percentage of orphans in other organisms. The discovery of new ligands has led to the elucidation of new regulatory mechanisms, target genes, pathways and functions. This review will highlight both the common as well as newly emerging traits and functions that characterize this particularly unique and important TF family.

An ecological study of cancer mortality rates in the United States with respect to solar ultraviolet-B doses, smoking, alcohol consumption and urban/rural residence

The Cohort Consortium Vitamin D Polling Project of Rarer Cancers (VDPP ) study failed to find a beneficial role of prediagnostic serum 25-hydroxyvitamin D [25(OH)D] levels on risk of seven types of rarer cancer: endometrial, esophageal, gastric, kidney, ovarian and pancreatic cancer and non-Hodgkin's lymphoma (NHL). However, ecological studies and studies of oral vitamin D intake have generally found solar ultraviolet B (UVB) and oral vitamin D inversely correlated with incidence and/or mortality rates of these cancers. To explore the discrepancy, I conducted an ecological study of cancer mortality rates for white Americans in the United States for 1950-1994 with data for 503 state economic areas in multiple linear regression analyses with respect to UVB for July, lung cancer, alcohol consumption and urban/rural residence. UVB was significantly inversely correlated with six types of cancer (not pancreatic cancer) in both periods. However, the adjusted R(2) values were much lower for cancers with lower mortality rates than those in an earlier ecological study that used state-averaged data. This finding suggests that the VDPP study may have had too few cases. Thus, the VDPP study should not be considered as providing strong evidence against the solar UVB-vitamin D-cancer hypothesis.