A low concentration of genistein induces estrogen receptor-alpha and insulin-like growth factor-I receptor interactions and proliferation in uterine leiomyoma cells

Estrogen receptor alpha mediated repression of PRICKLE1 destabilizes REST and promotes uterine fibroid pathogenesis

Uterine fibroids (leiomyomas), benign tumors of the myometrial smooth muscle layer, are present in over 75% of women, often causing severe pain, menorrhagia and reproductive dysfunction. The molecular pathogenesis of fibroids is poorly understood. We previously showed that the loss of REST (RE-1 Silencing Transcription factor), a tumor suppressor, in fibroids leads to activation of PI3K/AKT-mTOR pathway. We report here a critical link between estrogen receptor alpha (ERα) and the loss of REST, via PRICKLE1. PRICKLE1 expression is markedly lower in leiomyomas, and the suppression of PRICKLE1 significantly down regulates REST protein levels. Conversely, overexpression of PRICKLE1 resulted in the restoration of REST in cultured primary leiomyoma smooth muscle cells (LSMCs). Crucially, mice exposed neonatally to environmental estrogens, proven risk factors for fibroids, expressed lower levels of PRICKLE1 and REST in the myometrium. Using mice that lack either endogenous estrogen (Lhb -/- mice) or ERα (Esr1 -/- mice), we demonstrate that Prickle1 expression in the myometrium is suppressed by estrogen through ERα. Enhancer of zeste homolog 2 (EZH2) is known to participate in the repression of specific ERα target genes. Uterine leiomyomas express increased levels of EZH2 that inversely correlate with the expression of PRICKLE1. Using chromatin immunoprecipitation, we provide evidence for association of EZH2 with the PRICKLE1 promoter and for hypermethylation of H3K27 within the regulatory region of PRICKLE1 in leiomyomas. Additionally, siRNA mediated knockdown of EZH2 leads to restoration of PRICKLE1 in LSMCs. Collectively, our results identify a novel link between estrogen exposure and PRICKLE1/REST-regulated tumorigenic pathways in leiomyomas.

Dietary Flavonoids Consumption and Health: An Umbrella Review

SCOPE

The current evidence between dietary flavonoids consumption and multiple health outcomes is inadequate and inconclusive. To summarize and evaluate the evidence for dietary flavonoids consumption and multiple health outcomes, an umbrella review of meta-analyses and systematic reviews is conducted.

METHODS AND RESULTS

PubMed, Ovid-EMBASE, and the Cochrane Database of Systematic Reviews are searched up to January 2024. The study includes a total of 32 articles containing 24 unique health outcomes in this umbrella review. Meta-analyses are recalculated by using a random effects model. Separate analyses are performed based on the kind of different flavonoid subclasses. The study finds some unique associations such as flavonol and gastric cancer, isoflavone and uterine fibroids and endometrial cancer, total flavonoids consumption and lung cancer, ovarian cancer, and prostate cancer. Overall, the study confirms the negative associations between dietary flavonoids consumption and type 2 diabetes mellitus, cardiovascular diseases, breast cancer, colorectal cancer, lung cancer, and mortality, while positive associations are observed for prostate cancer and uterine fibroids.

CONCLUSION

Although dietary flavonoids are significantly associated with many outcomes, firm generalizable conclusions about their beneficial or harmful effects cannot be drawn because of the low certainty of evidence for most of outcomes. More well-designed primary studies are needed.

Estrogenic flavonoids and their molecular mechanisms of action

Flavonoids are a major group of phytoestrogens associated with physiological effects, and ecological and social impacts. Although the estrogenic activity of flavonoids was reported by researchers in the fields of medical, environmental and food studies, their molecular mechanisms of action have not been comprehensively reviewed. The estrogenic activity of the respective classes of flavonoids, anthocyanidins/anthocyanins, 2-arylbenzofurans/3-arylcoumarins/α-methyldeoxybenzoins, aurones/chalcones/dihydrochalcones, coumaronochromones, coumestans, flavans/flavan-3-ols/flavan-4-ols, flavanones/dihydroflavonols, flavones/flavonols, homoisoflavonoids, isoflavans, isoflavanones, isoflavenes, isoflavones, neoflavonoids, oligoflavonoids, pterocarpans/pterocarpenes, and rotenone/rotenoids, was summarized through a comprehensive literature search, and their structure-activity relationship, biological activities, signaling pathways, and applications were discussed. Although the respective classes of flavonoids contained at least one chemical mimicking estrogen, the mechanisms varied, such as those with estrogenic, anti-estrogenic, non-estrogenic, and biphasic activities, and additional activities through crosstalk/bypassing, which exert biological activities through cell signaling pathways. Such mechanistic variations of estrogen action are not limited to flavonoids and are observed among other broad categories of chemicals, thus this group of chemicals can be termed as the "estrogenome". This review article focuses on the connection of estrogen action mainly between the outer and the inner environments, which represent variations of chemicals and biological activities/signaling pathways, respectively, and form the basis to understand their applications. The applications of chemicals will markedly progress due to emerging technologies, such as artificial intelligence for precision medicine, which is also true of the study of the estrogenome including estrogenic flavonoids.

Fabaceae: a significant flavonoid source for plant and human health

The Fabaceae is recognized as the third largest and one of the most influential families among the flowering plants. Furthermore, its name is linked to “Legumes”, which represent a vast group of angiosperms in the continents utilized as crops, forages, and green manures. It is recognized for diverse constituents, covering both primary metabolites include lectins, chitinases, various proteases, and α-amylase inhibitors, as well as secondary metabolites include flavonoids, alkaloids, terpenoids, tannins, and phenolics. Fabaceae flavonoid plays an important role in the legumes’ adaptability to biological surroundings as defensive agents (phytoalexins) and as chemical signals in a symbiotic relationship with a bacterial species known as rhizobia. Considering their important role in plant defense and benefits to human healthiness, a number of studies on the Fabaceae plant have been performed, namely isolation and screening of the purified compounds and their biological activity. This study outlines specified issues on the chemical structure, biosynthesis, biological activities, and medicinal uses of Fabaceae compounds.

Genistein Up-Regulates the Expression of EGF and E-Cadherin in the Treatment of Senile Vaginitis

Investigating the therapeutic effect of genistein (Gen) on postmenopausal senile vaginitis (SV) and its mechanism of action. Adult SPF female Wistar rats were selected to establish a bilateral ovariectomized animal model (OVX), which simulated senile vaginitis dominated by estrogen deficiency in ovarian dysfunction. After 14 days of continuous treatment, the morphology of vaginal epithelial tissue was observed and various types of epithelial cells were counted, and the body mass and uterine and vaginal index of rats were measured. the levels of vaginal tissue secretion, microorganism, hormone and glycogen in each group were measured and the reproductive health was evaluated clinically. The protein expression and mRNA expression of epidermal growth factor (EGF) and E-cadherin (E-cadherin) in vaginal tissues were detected by immunohistochemistry and RT-PCR, respectively. Result showed that Genistein lowered vaginal pH, increased vaginal index and vaginal health score, thickened epithelial layers and improved vaginal tissue atrophy after administration. Genistein also increased the contents of glycogen and Lactobacillus in vagina, and promoted the expression of EGF, E-cadherin protein and mRNA. To sum up, there is no significant change in serum E2 and FSH levels, indicating that genistein has no effect on hormone levels in rats. genistein promoted the proliferation of vaginal epithelial cells, thickened epithelial layers and the vaginal wall, which improved the resistance of vaginal epithelium, the recovery of self-cleaning ability and healed the vaginal wound and erosive surface to improve atrophy.

Epigenomic and enhancer dysregulation in uterine leiomyomas

BACKGROUND

Uterine leiomyomas, also known as uterine fibroids or myomas, are the most common benign gynecological tumors and are found in women of reproductive and postmenopausal age. There is an exceptionally high prevalence of this tumor in women by the age of 50 years. Black women are particularly affected, with an increased incidence, earlier age of onset, larger and faster growing fibroids and greater severity of symptoms as compared to White women. Although advances in identifying genetic and environmental factors to delineate these fibroids have already been made, only recently has the role of epigenomics in the pathogenesis of this disease been considered.

OBJECTIVE AND RATIONALE

Over recent years, studies have identified multiple epigenomic aberrations that may contribute to leiomyoma development and growth. This review will focus on the most recent discoveries in three categories of epigenomic changes found in uterine fibroids, namely aberrant DNA methylation, histone tail modifications and histone variant exchange, and their translation into altered target gene architecture and transcriptional outcome. The findings demonstrating how the altered 3D shape of the enhancer can regulate gene expression from millions of base pairs away will be discussed. Additionally, translational implications of these discoveries and potential roadblocks in leiomyoma treatment will be addressed.

SEARCH METHODS

A comprehensive PubMed search was performed to identify published articles containing keywords relevant to the focus of the review, such as: uterine leiomyoma, uterine fibroids, epigenetic alterations, epigenomics, stem cells, chromatin modifications, extracellular matrix [ECM] organization, DNA methylation, enhancer, histone post-translational modifications and dysregulated gene expression. Articles until September 2021 were explored and evaluated to identify relevant updates in the field. Most of the articles focused on in the discussion were published between 2015 and 2021, although some key discoveries made before 2015 were included for background information and foundational purposes. We apologize to the authors whose work was not included because of space restrictions or inadvertent omission.

OUTCOMES

Chemical alterations to the DNA structure and of nucleosomal histones, without changing the underlying DNA sequence, have now been implicated in the phenotypic manifestation of uterine leiomyomas. Genome-wide DNA methylation analysis has revealed subsets of either suppressed or overexpressed genes accompanied by aberrant promoter methylation. Furthermore, differential promoter access resulting from altered 3D chromatin structure and histone modifications plays a role in regulating transcription of key genes thought to be involved in leiomyoma etiology. The dysregulated genes function in tumor suppression, apoptosis, angiogenesis, ECM formation, a variety of cancer-related signaling pathways and stem cell differentiation. Aberrant DNA methylation or histone modification is also observed in altering enhancer architecture, which leads to changes in enhancer-promoter contact strength, producing novel explanations for the overexpression of high mobility group AT-hook 2 and gene dysregulation found in mediator complex subunit 12 mutant fibroids. While many molecular mechanisms and epigenomic features have been investigated, the basis for the racial disparity observed among those in the Black population remains unclear.

WIDER IMPLICATIONS

A comprehensive understanding of the exact pathogenesis of uterine leiomyoma is lacking and requires attention as it can provide clues for prevention and viable non-surgical treatment. These findings will widen our knowledge of the role epigenomics plays in the mechanisms related to uterine leiomyoma development and highlight novel approaches for the prevention and identification of epigenome targets for long-term non-invasive treatment options of this significantly common disease.

Genistein: Dual Role in Women's Health

Advanced research in recent years has revealed the important role of nutrients in the protection of women's health and in the prevention of women's diseases. Genistein is a phytoestrogen that belongs to a class of compounds known as isoflavones, which structurally resemble endogenous estrogen. Genistein is most often consumed by humans via soybeans or soya products and is, as an auxiliary medicinal, used to treat women's diseases. In this review, we focused on analyzing the geographic distribution of soybean and soya product consumption, global serum concentrations of genistein, and its metabolism and bioactivity. We also explored genistein's dual effects in women's health through gathering, evaluating, and summarizing evidence from current in vivo and in vitro studies, clinical observations, and epidemiological surveys. The dose-dependent effects of genistein, especially when considering its metabolites and factors that vary by individuals, indicate that consumption of genistein may contribute to beneficial effects in women's health and disease prevention and treatment. However, consumption and exposure levels are nuanced because adverse effects have been observed at lower concentrations in in vitro models. Therefore, this points to the duplicity of genistein as a possible therapeutic agent in some instances and as an endocrine disruptor in others.

Nutrition in Gynecological Diseases: Current Perspectives

Diet and nutrition are fundamental in maintaining the general health of populations, including women's health. Health status can be affected by nutrient deficiency and vice versa. Gene-nutrient interactions are important contributors to health management and disease prevention. Nutrition can alter gene expression, as well as the susceptibility to diseases, including cancer, through several mechanisms. Gynecological diseases in general are diseases involving the female reproductive system and include benign and malignant tumors, infections, and endocrine diseases. Benign diseases such as uterine fibroids and endometriosis are common, with a negative impact on women's quality of life, while malignant tumors are among the most common cause of death in the recent years. In this comprehensive review article, a bibliographic search was performed for retrieving information about nutrients and how their deficiencies can be associated with gynecological diseases, namely polycystic ovary syndrome, infertility, uterine fibroids, endometriosis, dysmenorrhea, and infections, as well as cervical, endometrial, and ovarian cancers. Moreover, we discussed the potential beneficial impact of promising natural compounds and dietary supplements on alleviating these significant diseases.

Targeting DNA Methylation Depletes Uterine Leiomyoma Stem Cell-enriched Population by Stimulating Their Differentiation

Uterine leiomyoma (LM) is the most common tumor in women and can cause severe morbidity. Leiomyoma growth requires the maintenance and proliferation of a stem cell population. Dysregulated deoxyribonucleic acid (DNA) methylation has been reported in LM, but its role in LM stem cell regulation remains unclear. Here, we fluorescence-activated cell sorting (FACS)-sorted cells from human LM tissues into 3 populations: LM stem cell-like cells (LSC, 5%), LM intermediate cells (LIC, 7%), and differentiated LM cells (LDC, 88%), and we analyzed the transcriptome and epigenetic landscape of LM cells at different differentiation stages. Leiomyoma stem cell-like cells harbored a unique methylome, with 8862 differentially methylated regions compared to LIC and 9444 compared to LDC, most of which were hypermethylated. Consistent with global hypermethylation, transcript levels of TET1 and TET3 methylcytosine dioxygenases were lower in LSC. Integrative analyses revealed an inverse relationship between methylation and gene expression changes during LSC differentiation. In LSC, hypermethylation suppressed the genes important for myometrium- and LM-associated functions, including muscle contraction and hormone action, to maintain stemness. The hypomethylating drug, 5'-Aza, stimulated LSC differentiation, depleting the stem cell population and inhibiting tumor initiation. Our data suggest that DNA methylation maintains the pool of LSC, which is critical for the regeneration of LM tumors.

An HMGA2-p62-ERα axis regulates uterine leiomyomas proliferation

Uterine leiomyomas (ULM) are a major public health issue contributing to high morbidity and poor pregnancy outcomes. However, its molecular pathogenesis is poorly understood. HMGA2-ULM is the second major subtype of human ULM and associates with large sizes, fast-growth, and high percentages of estrogen receptor α (ERα). As altered ERα expression plays a distinct role in ULM growth, here, we investigate a regulatory mechanism driving ULM growth via HMGA2 and ERα. We reveal a positive correlation of HMGA2 with ERα protein and demonstrate that HMGA2 promotes ULM cells proliferation via ERα. In addition, autophagy pathway and p62/SQSTM1 (a selective autophagy receptor) are found to participate in the regulation of HMGA2 and ERα. Moreover, HMGA2 suppresses the transcription of p62 by binding to its promoter, meanwhile, p62 interacts with ERα, and inhibition of p62 increases ERα expression and enhances cell viability in ULM, suggesting a novel mechanism of the HMGA2-p62-ERα axis in ULM proliferation. Notably, rapamycin, a familiar autophagy agonist, reduces ERα levels and the proliferation ability of ULM cells. This study demonstrates a causal role of the HMGA2-p62-ERα axis in preventing autophagy and increasing ERα expression in HMGA2-ULM. Therefore, blocking HMGA2-p62-ERα axis and targeting autophagy pathway establish a roadmap toward HMGA2-ULM medical treatment.

MiR-148a inhibits oral squamous cell carcinoma progression through ERK/MAPK pathway via targeting IGF-IR

OBJECTIVE

The current study aimed to investigate the functional roles and clinical significance of microRNA-148a (miR-148a) in the progression of oral squamous cell carcinoma (OSCC).

METHODS

Relative expression of miR-148a in OSCC cells and tissues were detected using quantitative real-time polymerase chain reaction (qRT-PCR). Chi-square test was performed to estimate the relationship between miR-148a expression and clinical characteristics of OSCC patients. Cell transfection was carried out using Lipofectamine® 2000. Biological behaviors of tumor cells were detected using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and transwell assays. Bioinformatics analysis and luciferase reporter assay were used to identify the target genes of miR-148a. Protein expression was detected through Western blot analysis.

RESULTS

MiR-148a expression was obviously decreased in OSCC tissues and cells, and such down-regulation was closely correlated with lymph node metastasis (P=0.027) and tumor node metastasis (TNM) stage (P=0.001) of OSCC patients. miR-148a overexpression could significantly impair OSCC cell proliferation, migration and invasion in vitro (P<0.05 for all). Insulin-like growth factor-I receptor (IGF-IR) was a potential target of miR-148a. MiR-148a could inhibit ERK/MAPK signaling pathway through targeting IGF-IR.

CONCLUSION

MiR-148a plays an anti-tumor role in OSCC and inhibits OSCC progression through suppressing ERK/MAPK pathway via targeting IGF-IR.

The effect of ulipristal acetate on tumor necrosis factor α, insulin-like growth factor 1, and plasminogen activator inhibitor-1 serum levels in patients with symptomatic uterine fibroids

Introduction

Uterine fibroids (UFs) are benign tumors of the female reproductive system originating from the smooth muscle of the uterus. Currently, progesterone is known to play a key role in the differentiation of the myometrial tissue to form UFs and their abnormal growth. The mechanism of action of progesterone in UF tumorigenesis involves its effect on increasing the concentrations and dysregulation of selected growth factors.

Material and methods

A retrospective cohort study was performed to evaluate and compare tumor necrosis factor α (TNF-α), insulin-like growth factor 1 (IGF-1), plasminogen activator inhibitor-1 (PAI-1) serum concentrations in patients with UFs without prior hormonal treatment, patients with UFs treated with a 3-month standard ulipristal acetate (UPA - a type of selective progesterone receptor modulator) scheme (5 mg/day) and in control patients without UFs. A total of 120 patients were divided into 3 groups (controls, UFs with UPA treatment, UFs without UPA treatment).

Results

There were no significant differences in TNF-α serum concentrations between patients with UFs who underwent UPA treatment and patients who did not. Serum concentrations of IGF-1 and PAI-1 did not show significant intergroup differences.

Conclusions

No significant differences were found between TNF-α concentrations in the serum of patients with UFs treated with UPA, and patients without UPA treatment. In addition, our data analysis did not show significant differences in the concentrations of IGF-1 and PAI-1 between patients with UFs and the control group. Further studies on the dependence of specific symptoms on selected growth factors are mandatory.

Advanced 3D Imaging of Uterine Leiomyoma's Morphology by Propagation-based Phase-Contrast Microtomography

Uterine leiomyoma is the most common benign smooth muscle tumor in women pelvis, originating from the myometrium. It is caused by a disorder of fibrosis, with a large production and disruption of extracellular matrix (ECM). Medical treatments are still very limited and no preventative therapies have been developed. We supposed that synchrotron-based phase-contrast microtomography (PhC-microCT) may be an appropriate tool to assess the 3D morphology of uterine leiomyoma, without the use of any contrast agent. We used this technique to perform the imaging and the quantitative morphometric analysis of healthy myometrium and pathologic leiomyomas. The quantitative morphometric analysis of collagen bundles was coupled to the Roschger approach. This method, previously only used to evaluate mineralized bone density distribution, was applied here to study the fibrosis mass density distribution in healthy and pathologic biopsies from two patients. This protocol was shown to be powerful in studying uterine leiomyomas, detecting also small signs of the ECM alteration. This is of paramount importance not only for the follow-up of the present study, i.e. the investigation of different compounds and their possible therapeutic benefits, but also because it offers new methodologic possibilities for future studies of the ECM in soft tissues of different body districts.

Bisphenol A induces human uterine leiomyoma cell proliferation through membrane-associated ERα36 via nongenomic signaling pathways

The role of ERα36 in regulating BPA's effects and its potential as a risk factor for human uterine fibroids were evaluated. BPA at low concentrations (10^-6 μM - 10 μM) increased proliferation by facilitating progression of hormonally regulated, immortalized human uterine leiomyoma (ht-UtLM; fibroid) cells from G₀-G₁ into S phase of the cell cycle; whereas, higher concentrations (100 μM-200 μM) decreased growth. BPA upregulated ERα36 gene and protein expression, and induced increased SOS1 and Grb2 protein expression, both of which are mediators of the MAPK_p44/42/ERK1/2 pathway. EGFR (pEGFR), Ras, and MAPK_p44/42 were phosphorylated with concurrent Src activation in ht-UtLM cells within 10 min of BPA exposure. BPA enhanced colocalization of phosphorylated Src (pSrc) to ERα36 and coimmunoprecipitation of pSrc with pEGFR. Silencing ERα36 with siERα36 abolished the above effects. BPA induced proliferation in ht-UtLM cells through membrane-associated ERα36 with activation of Src, EGFR, Ras, and MAPK nongenomic signaling pathways.

A-Kinase Anchoring Protein 13 (AKAP13) Augments Progesterone Signaling in Uterine Fibroid Cells

CONTEXT

Uterine leiomyomata (fibroids) are prevalent sex hormone‒dependent tumors with an altered response to mechanical stress. Ulipristal acetate, a selective progesterone receptor (PR) modulator, significantly reduces fibroid size in patients. However, PR signaling in fibroids and its relationship to mechanical signaling are incompletely understood.

OBJECTIVE

Our prior studies revealed that A-kinase anchoring protein 13 (AKAP13) was overexpressed in fibroids and contributed to altered mechanotransduction in fibroids. Because AKAP13 augmented nuclear receptor signaling in other tissues, we sought to determine whether AKAP13 might influence PR signaling in fibroids.

METHODS AND RESULTS

Fibroid samples from patients treated with ulipristal acetate or placebo were examined for AKAP13 expression by using immunohistochemistry. In immortalized uterine fibroid cell lines and COS-7 cells, we observed that AKAP13 increased ligand-dependent PR activation of luciferase reporters and endogenous progesterone-responsive genes for PR-B but not PR-A. Inhibition of ERK reduced activation of PR-dependent signaling by AKAP13, but inhibition of p38 MAPK had no effect. In addition, glutathione S-transferase‒binding assays revealed that AKAP13 was bound to PR-B through its carboxyl terminus.

CONCLUSION

These data suggest an intersection of mechanical signaling and PR signaling involving AKAP13 through ERK. Further elucidation of the integration of mechanical and hormonal signaling pathways in fibroids may provide insight into fibroid development and suggest new therapeutic strategies for treatment.

GmMYB58 and GmMYB205 are seed-specific activators for isoflavonoid biosynthesis in Glycine max

GmMYB58 and GmMYB205 are key positive regulators that are involved in isoflavonoid biosynthesis in seeds of Glycine max, and they activate the expression of several structural genes in the isoflavonoid pathway. MYB transcription factors (TFs) are major regulators involved in flavonoid/isoflavonoid biosynthesis in many plant species. However, functions of most MYB TFs remain unknown in flavonoid/isoflavonoid pathway in Glycine max. In this study, we identified 321 MYB TFs by genome-wide searching, and further isolated and functionally characterized two MYB TFs, GmMYB58 and GmMYB205. The deduced GmMYB58 and GmMYB205 proteins contain highly conserved R2R3 repeat domain at the N-terminal region that is the signature motif of R2R3-type MYB TFs. GmMYB58 and GmMYB205 were highly expressed in early seed development stages than in the other tested organs. GmMYB58 and GmMYB205 GFP fusion proteins were found to be localized in the nucleus when they were transiently expressed in Arabidopsis thaliana mesophyll protoplast. Both GmMYB58 and GmMYB205 can activate the promoter activities of GmCHS, GmIFS2, and GmHID in the transient trans-activation assays, and the activation of GmHID by both GmMYB58 and GmMYB205 was further confirmed by yeast one-hybrid assay. In addition, over-expression of GmMYB58 and GmMYB205 resulted in significant increases in expression levels of several pathway genes in soybean hairy roots, in particular, IFS2 by more than fivefolds in GmMYB205-over-expressing lines. Moreover, isoflavonoid contents were remarkably enhanced in the GmMYB58 and GmMYB205 over-expressing hairy roots than in the control. Our results suggest that GmMYB58 and GmMYB205 are seed-specific TFs, and they can enhance isoflavonoid biosynthesis mainly through the regulation of GmIFS2 and GmHID in G. max.

Aspirin inhibits the proliferation of human uterine leiomyoma cells by downregulation of K‑Ras‑p110α interaction

Aspirin has been confirmed as an effective antitumor drug in various cancers. However, the relationship between aspirin and uterine leiomyoma is still underexplored. Here, we explored the effects of aspirin on human uterine leiomyoma cells and provide insights into the underlying mechanisms. Cell Counting Kit-8 (CCK-8) and flow cytometry analysis showed that aspirin treatment inhibited cell proliferation and promoted cell cycle arrest at G0/G1 phase in a dose- and time‑dependent manner of human uterine leiomyoma cells. Further studies revealed that aspirin blocked the interaction between K-Ras and p110α by co-immunoprecipitation and immunofluorescence. Western blotting demonstrated K‑Ras‑p110α interaction was required for the effects of aspirin‑induced inhibition on cell growth and cell cycle transition via cell cycle regulators, including cyclin D1 and cyclin-dependent kinase 2 (CDK2). PI3K/Akt/caspase signaling pathway was involved in human uterine leiomyoma cell growth under aspirin treatment. Taken together, these results suggest that aspirin inhibited human uterine leiomyoma cell growth by regulating K‑Ras‑p110α interaction. Aspirin which targeting on interaction between K-Ras and p110α may serve as a new therapeutic drug for uterine leiomyoma treatment.

Epidemiology of Uterine Fibroids: From Menarche to Menopause

Uterine leiomyomata (UL) have a substantial impact on women's health, but relatively few studies have identified opportunities for primary prevention of these neoplasms. Most established risk factors are not modifiable, including premenopausal age, African ancestry, age at menarche, and childbearing history. The main challenge in studying UL is that a large proportion of tumors are asymptomatic. Herein, we review the epidemiology of UL from published studies to date. We highlight the advantages of ultrasound screening studies and the ways in which their innovative methods have helped clarify the etiology of disease. We conclude with a discussion of promising new hypotheses.

Epigenetic regulation of transcription factor promoter regions by low-dose genistein through mitogen-activated protein kinase and mitogen-and-stress activated kinase 1 nongenomic signaling

Background

The phytoestrogen, genistein at low doses nongenomically activates mitogen-activated protein kinase p44/42 (MAPK_p44/42) via estrogen receptor alpha (ERα) leading to proliferation of human uterine leiomyoma cells. In this study, we evaluated if MAPK_p44/42 could activate downstream effectors such as mitogen- and stress-activated protein kinase 1 (MSK1), which could then epigenetically modify histone H3 by phosphorylation following a low dose (1 μg/ml) of genistein.

Results

Using hormone-responsive immortalized human uterine leiomyoma (ht-UtLM) cells, we found that genistein activated MAPK_p44/42 and MSK1, and also increased phosphorylation of histone H3 at serine10 (H3S10ph) in ht-UtLM cells. Colocalization of phosphorylated MSK1 and H3S10ph was evident by confocal microscopy in ht-UtLM cells (r = 0.8533). Phosphorylation of both MSK1and H3S10ph was abrogated by PD98059 (PD), a MEK1 kinase inhibitor, thereby supporting genistein’s activation of MSK1 and Histone H3 was downstream of MAPK_p44/42. In proliferative (estrogenic) phase human uterine fibroid tissues, phosphorylated MSK1 and H3S10ph showed increased immunoexpression compared to normal myometrial tissues, similar to results observed in in vitro studies following low-dose genistein administration. Real-time RT-PCR arrays showed induction of growth-related transcription factor genes, EGR1, Elk1, ID1, and MYB (cMyb) with confirmation by western blot, downstream of MAPK in response to low-dose genistein in ht-UtLM cells. Additionally, genistein induced associations of promoter regions of the above transcription factors with H3S10ph as evidenced by Chromatin Immunoprecipitation (ChIP) assays, which were inhibited by PD. Therefore, genistein epigenetically modified histone H3 by phosphorylation of serine 10, which was regulated by MSK1 and MAPK activation.

Conclusion

Histone H3 phosphorylation possibly represents a mechanism whereby increased transcriptional activation occurs following low-dose genistein exposure.

Electronic supplementary material

The online version of this article (doi:10.1186/s12964-016-0141-2) contains supplementary material, which is available to authorized users.

Evasion of anti-growth signaling: A key step in tumorigenesis and potential target for treatment and prophylaxis by natural compounds

The evasion of anti-growth signaling is an important characteristic of cancer cells. In order to continue to proliferate, cancer cells must somehow uncouple themselves from the many signals that exist to slow down cell growth. Here, we define the anti-growth signaling process, and review several important pathways involved in growth signaling: p53, phosphatase and tensin homolog (PTEN), retinoblastoma protein (Rb), Hippo, growth differentiation factor 15 (GDF15), AT-rich interactive domain 1A (ARID1A), Notch, insulin-like growth factor (IGF), and Krüppel-like factor 5 (KLF5) pathways. Aberrations in these processes in cancer cells involve mutations and thus the suppression of genes that prevent growth, as well as mutation and activation of genes involved in driving cell growth. Using these pathways as examples, we prioritize molecular targets that might be leveraged to promote anti-growth signaling in cancer cells. Interestingly, naturally occurring phytochemicals found in human diets (either singly or as mixtures) may promote anti-growth signaling, and do so without the potentially adverse effects associated with synthetic chemicals. We review examples of naturally occurring phytochemicals that may be applied to prevent cancer by antagonizing growth signaling, and propose one phytochemical for each pathway. These are: epigallocatechin-3-gallate (EGCG) for the Rb pathway, luteolin for p53, curcumin for PTEN, porphyrins for Hippo, genistein for GDF15, resveratrol for ARID1A, withaferin A for Notch and diguelin for the IGF1-receptor pathway. The coordination of anti-growth signaling and natural compound studies will provide insight into the future application of these compounds in the clinical setting.

A multi-targeted approach to suppress tumor-promoting inflammation

Cancers harbor significant genetic heterogeneity and patterns of relapse following many therapies are due to evolved resistance to treatment. While efforts have been made to combine targeted therapies, significant levels of toxicity have stymied efforts to effectively treat cancer with multi-drug combinations using currently approved therapeutics. We discuss the relationship between tumor-promoting inflammation and cancer as part of a larger effort to develop a broad-spectrum therapeutic approach aimed at a wide range of targets to address this heterogeneity. Specifically, macrophage migration inhibitory factor, cyclooxygenase-2, transcription factor nuclear factor-κB, tumor necrosis factor alpha, inducible nitric oxide synthase, protein kinase B, and CXC chemokines are reviewed as important antiinflammatory targets while curcumin, resveratrol, epigallocatechin gallate, genistein, lycopene, and anthocyanins are reviewed as low-cost, low toxicity means by which these targets might all be reached simultaneously. Future translational work will need to assess the resulting synergies of rationally designed antiinflammatory mixtures (employing low-toxicity constituents), and then combine this with similar approaches targeting the most important pathways across the range of cancer hallmark phenotypes.

Role of epidermal growth factor in pathogenesis of uterine leiomyomas

OBJECTIVE

To investigate the role of epidermal growth factor (EGF) in the pathogenesis of uterine leiomyomas.

METHODS

Human myometrial smooth muscle cells (HM-SMCs) and smooth muscle cells of human uterine leiomyomas (HL-SMCs) were separated from patients' specimens and cultured. After processed by EGF or PD98059 (inhibitor of MKK/MEK) +EGF, the proliferation rate of both SMCs was detected by BrdU method and the phosphorylation level of p44/42 mitogen-activated protein kinase (MAPK) was determined by Western-blot. After different processing time by EGF, the phosphorylation levels of p44/42 MAPK and AKT and p27 expression level in both SMCs were detected by Western-blot.

RESULTS

EGF could significantly promote HL-SMCs proliferation and PD98059 could inhibit this effect (P<0.05); besides, PD98059 could inhibit the increase of the phosphorylation level of p44/42 MAPK in both SMCs induced by EGF. When the processing time by EGF was over 15min, the phosphorylation levels of p44/42 MAPK and AKT in both SMCs decreased sharply and were close to zero; p27 expression in HM-SMCs raised significantly while the upregulation in HL-SMCs was little.

CONCLUSIONS

EGF could not cause activation of EGFR because of the dephosphorylation of p44/42 MAPK and AKT in HL-SMCs, which caused p27 expression insufficiently and cell cycle dysregulation.

Cadmium and proliferation in human uterine leiomyoma cells: evidence of a role for EGFR/MAPK pathways but not classical estrogen receptor pathways

BACKGROUND

It has been proposed that cadmium (Cd) is an environmental "metalloestrogen" and that its action is mediated via the estrogen receptor (ER). Cd mimics the effects of estrogen in the rat uterus, and blood Cd concentrations positively correlate with ER levels in uteri of women with fibroids.

OBJECTIVES

In the present study we explored whether Cd could stimulate proliferation of estrogen-responsive human uterine leiomyoma (ht-UtLM) cells and uterine smooth muscle cells (ht-UtSMCs) through classical interactions with ERα and ERβ, or by nongenomic mechanisms.

METHODS

We used estrogen response element (ERE) reporters, phosphorylated receptor tyrosine kinase arrays, Western blot analysis, estrogen binding, and cell proliferation assays to evaluate the effects of Cd on ht-UtLM cells and ht-UtSMCs.

RESULTS

Cd stimulated growth of both cell types at lower concentrations and inhibited growth at higher concentrations (≥ 50 μM). Cd did not significantly bind to ERα or ERβ, nor did it show transactivation in both cell types transiently transfected with ERE reporter genes. However, in both cells types, Cd (0.1 μM and 10 μM) activated p44/42 MAPK (ERK1/2), and a MAPK inhibitor (PD98059) abrogated Cd-induced cell proliferation. Cd in ht-UtLM cells, but not in ht-UtSMCs, activated the growth factor receptors EGFR, HGFR, and VEGF-R1 upstream of MAPK. Additional studies in ht-UtLM cells showed that AG1478, an EGFR inhibitor, abolished Cd-induced phosphorylation of EGFR and MAPK.

CONCLUSIONS

Our results show that low concentrations of Cd stimulated cell proliferation in estrogen-responsive uterine cells by nongenomic activation of MAPK, but not through classical ER-mediated pathways.

Construction of a high-density genetic map based on large-scale markers developed by specific length amplified fragment sequencing (SLAF-seq) and its application to QTL analysis for isoflavone content in Glycine max

BACKGROUND

Quantitative trait locus (QTL) mapping is an efficient approach to discover the genetic architecture underlying complex quantitative traits. However, the low density of molecular markers in genetic maps has limited the efficiency and accuracy of QTL mapping. In this study, specific length amplified fragment sequencing (SLAF-seq), a new high-throughput strategy for large-scale SNP discovery and genotyping based on next generation sequencing (NGS), was employed to construct a high-density soybean genetic map using recombinant inbred lines (RILs, Luheidou2×Nanhuizao, F5:8). With this map, the consistent QTLs for isoflavone content across various environments were identified.

RESULTS

In total, 23 Gb of data containing 87,604,858 pair-end reads were obtained. The average coverage for each SLAF marker was 11.20-fold for the female parent, 12.51-fold for the male parent, and an average of 3.98-fold for individual RILs. Among the 116,216 high-quality SLAFs obtained, 9,948 were polymorphic. The final map consisted of 5,785 SLAFs on 20 linkage groups (LGs) and spanned 2,255.18 cM in genome size with an average distance of 0.43 cM between adjacent markers. Comparative genomic analysis revealed a relatively high collinearity of 20 LGs with the soybean reference genome. Based on this map, 41 QTLs were identified that contributed to the isoflavone content. The high efficiency and accuracy of this map were evidenced by the discovery of genes encoding isoflavone biosynthetic enzymes within these loci. Moreover, 11 of these 41 QTLs (including six novel loci) were associated with isoflavone content across multiple environments. One of them, qIF20-2, contributed to a majority of isoflavone components across various environments and explained a high amount of phenotypic variance (8.7%-35.3%). This represents a novel major QTL underlying isoflavone content across various environments in soybean.

CONCLUSIONS

Herein, we reported a high-density genetic map for soybean. This map exhibited high resolution and accuracy. It will facilitate the identification of genes and QTLs underlying essential agronomic traits in soybean. The novel major QTL for isoflavone content is useful not only for further study on the genetic basis of isoflavone accumulation, but also for marker-assisted selection (MAS) in soybean breeding in the future.

Differential effects of tumor necrosis factor-α on matrix metalloproteinase-2 expression in human myometrial and uterine leiomyoma smooth muscle cells

STUDY QUESTION

Does tumor necrosis factor-α (TNF-α) differentially regulate matrix metalloproteinase-2 (MMP-2) expression in leiomyomas compared with normal myometrium?

SUMMARY ANSWER

TNF-α up-regulates MMP-2 expression and stimulates cell migration through the activation of extracellular signal-regulated kinase (ERK) signaling pathway in leiomyoma smooth muscle cells (SMCs), but not in normal myometrial SMCs.

WHAT IS KNOWN ALREADY

Uterine leiomyoma, the benign smooth muscle cell tumor, is the single most common indication for hysterectomy. High expression of MMPs or TNF-α has been reported in uterine leiomyomas; however, the molecular mechanism underlying these observations remains unknown.

STUDY DESIGN, SIZE, DURATION

Samples were obtained between 2009 and 2013 from 12 women of reproductive age at the proliferative phase of the menstrual cycle by hysterectomy. Leiomyomas and matched normal myometrium from each woman were analyzed in vitro.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Western blot, RT-qPCR and a wound-healing assay were used to investigate the effects of TNF-α on MMP-2 expression and intracellular signal transduction in cultured SMCs from leiomyomas and matched myometrium.

MAIN RESULTS AND THE ROLE OF CHANCE

Western blot and RT-qPCR analyses using tissues from clinical patients showed that the levels of MMP-2 protein (P = 0.008) and mRNA (P = 0.009) were significantly higher in uterine leiomyomas compared with their matched myometrium. Treatment with TNF-α significantly up-regulated the protein (P = 0.039) and mRNA (P = 0.037) levels of MMP-2 in cultured leiomyoma SMCs but not in matched myometrial SMCs. The extracellular signal-regulated kinase (ERK) and nuclear factor-kappa B (NF-κB) pathways were activated by TNF-α in leiomyoma SMCs. Specific inhibitors of the ERK or NF-κB pathway (PD98059 or Bay11-7082) suppressed TNF-α-induced MMP-2 expression in leiomyoma SMCs. The wound-healing assay revealed that TNF-α promoted the migration of cultured leiomyoma SMCs (P = 0.036); however, PD98059 compromised the cell migration triggered by TNF-α.

LIMITATIONS, REASONS FOR CAUTION

This study is descriptive and although we observed clear differential regulation of MMP-2 by TNF-α at mRNA and protein levels in leiomyoma, future studies are needed to identify why the difference in TNF-α response exists between human leiomyoma tissue and normal myometrium. Including some of the experiments such as transfection studies for TNF-α and MMP-2 promoter mapping could have added more insight as to why this difference exists. In addition, further studies in vivo are needed to verify the results obtained from primary cultured SMCs.

WIDER IMPLICATIONS OF THE FINDINGS

Considering the positive effect of TNF-α on leiomyoma SMC migration, strategies targeting TNF-α, in parallel with the production of more specific inhibitors of MMPs, may provide alternative therapeutic approaches for the treatment of leiomyoma.

STUDY FUNDING/COMPETING INTERESTS

This work was partially supported by grants from the Program for New Century Excellent Talents in University (NCET-12-0282), National Natural Science Foundation of China (81371620) and Tianjin Natural Science Foundation (12JCZDJC24900). The authors have no conflicts of interest to declare.

Use of dietary phytochemicals to target inflammation, fibrosis, proliferation, and angiogenesis in uterine tissues: promising options for prevention and treatment of uterine fibroids?

Uterine leiomyomas (fibroids, myomas) are the most common benign tumors of female reproductive tract. They are highly prevalent, with 70-80% of women burdened by the end of their reproductive years. Fibroids are a leading cause of pelvic pain, abnormal vaginal bleeding, pressure on the bladder, miscarriage, and infertility. They are the leading indication for hysterectomy, and costs exceed 6 billion dollars annually in the United States. Unfortunately, no long-term medical treatments are available. Dysregulation of inflammatory processes are thought to be involved in the initiation of leiomyoma and extracellular matrix deposition, cell proliferation, and angiogenesis are the key cellular events implicated in leiomyoma growth. In modern pharmaceutical industries, dietary phytochemicals are used as source of new potential drugs for many kinds of tumors. Dietary phytochemicals may exert therapeutic effects by interfering with key cellular events of the tumorigenesis process. At present, a negligible number of phytochemicals have been tested as therapeutic agents against fibroids. In this context, our aim was to introduce some of the potential dietary phytochemicals that have shown anti-inflammatory, antiproliferative, antifibrotic, and antiangiogenic activities in different biological systems. This review could be useful to stimulate the evaluation of these phytochemicals as possible therapies for uterine fibroids.

Does nonylphenol promote the growth of uterine fibroids?

OBJECTIVE

To study the effect and mechanism of action of nonylphenol (NP), an environmental oestrogen, on uterine leiomyoma (UL) cells.

METHODS

Primary culture and subculture of human UL cells, identified as smooth muscle cells by immunocytochemical staining with a monoclonal anti-α-smooth muscle actin antibody, were performed. The viability of cells treated with various concentrations of NP for 24, 48 and 72h was determined by CCK-8 assay. mRNA expression of oestrogen receptor α (ERα), insulin-like growth factor 1 (IGF-1) and vascular endothelial growth factor (VEGF) was detected using real-time quantitative polymerase chain reaction, and protein expression was detected using Western blot analysis for all groups.

RESULTS

NP promoted the growth of UL cells and expression of ERα, IGF-1 and VEGF; this was positively correlated with the concentration and duration of NP treatment.

CONCLUSION

NP promotes the growth of UL cells. The mechanism of action appears to be over-expression of IGF-1 and VEGF, up-regulated by ERα, resulting in the growth of UL cells.

Proceedings from the Third National Institutes of Health International Congress on Advances in Uterine Leiomyoma Research: comprehensive review, conference summary and future recommendations

BACKGROUND Uterine fibroids are the most common gynecologic tumors in women of reproductive age yet the etiology and pathogenesis of these lesions remain poorly understood. Age, African ancestry, nulliparity and obesity have been identified as predisposing factors for uterine fibroids. Symptomatic tumors can cause excessive uterine bleeding, bladder dysfunction and pelvic pain, as well as associated reproductive disorders such as infertility, miscarriage and other adverse pregnancy outcomes. Currently, there are limited noninvasive therapies for fibroids and no early intervention or prevention strategies are readily available. This review summarizes the advances in basic, applied and translational uterine fibroid research, in addition to current and proposed approaches to clinical management as presented at the 'Advances in Uterine Leiomyoma Research: 3rd NIH International Congress'. Congress recommendations and a review of the fibroid literature are also reported. METHODS This review is a report of meeting proceedings, the resulting recommendations and a literature review of the subject. RESULTS The research data presented highlights the complexity of uterine fibroids and the convergence of ethnicity, race, genetics, epigenetics and environmental factors, including lifestyle and possible socioeconomic parameters on disease manifestation. The data presented suggest it is likely that the majority of women with uterine fibroids will have normal pregnancy outcomes; however, additional research is warranted. As an alternative to surgery, an effective long-term medical treatment for uterine fibroids should reduce heavy uterine bleeding and fibroid/uterine volume without excessive side effects. This goal has not been achieved and current treatments reduce symptoms only temporarily; however, a multi-disciplined approach to understanding the molecular origins and pathogenesis of uterine fibroids, as presented in this report, makes our quest for identifying novel targets for noninvasive, possibly nonsystemic and effective long-term treatment very promising. CONCLUSIONS The Congress facilitated the exchange of scientific information among members of the uterine leiomyoma research and health-care communities. While advances in research have deepened our knowledge of the pathobiology of fibroids, their etiology still remains incompletely understood. Further needs exist for determination of risk factors and initiation of preventive measures for fibroids, in addition to continued development of new medical and minimally invasive options for treatment.

Estrogen receptor α in cancer-associated fibroblasts suppresses prostate cancer invasion via modulation of thrombospondin 2 and matrix metalloproteinase 3

The prostate cancer (PCa) microenvironment contains active stromal cells known as cancer-associated fibroblasts (CAF) that may play important roles in influencing tumor progression. Here we studied the role of CAF estrogen receptor alpha (ERα) and found that it could protect against PCa invasion. Immunohistochemistry on prostatectomy specimens showed that PCa patients with ERα-positive stroma had a significantly lower risk for biochemical recurrence. In vitro invasion assays further confirmed that the stromal ERα was able to reduce PCa cell invasion. Dissection of the molecular mechanism revealed that the CAF ERα could function through a CAF-epithelial interaction via selectively upregulating thrombospondin 2 (Thbs2) and downregulating matrix metalloproteinase 3 (MMP3) at the protein and messenger RNA levels. Chromatin immunoprecipitation assays further showed that ERα could bind to an estrogen response element on the promoter of Thbs2. Importantly, knockdown of Thbs2 led to increased MMP3 expression and interruption of the ERα mediated invasion suppression, providing further evidence of an ERα-Thbs2-MMP3 axis in CAF. In vivo studies using athymic nude mice injected with CWR22Rv1 (22Rv1) PCa epithelial cells and CAF cells ± ERα also confirmed that mice coimplanted with PCa cells and CAF ERα+ cells had less tumor foci in the pelvic lymph nodes, less metastases, and tumors showed less angiogenesis, MMP3, and MMP9 (an MMP3 downstream target) positive staining. Together, these data suggest that CAF ERα could play protective roles in suppressing PCa metastasis. Our results may lead to developing new and alternative therapeutic approaches to battle PCa via controlling ERα signaling in CAF.

Progesterone action in endometrial cancer, endometriosis, uterine fibroids, and breast cancer

Progesterone receptor (PR) mediates the actions of the ovarian steroid progesterone, which together with estradiol regulates gonadotropin secretion, prepares the endometrium for implantation, maintains pregnancy, and differentiates breast tissue. Separation of estrogen and progesterone actions in hormone-responsive tissues remains a challenge. Pathologies of the uterus and breast, including endometrial cancer, endometriosis, uterine fibroids, and breast cancer, are highly associated with estrogen, considered to be the mitogenic factor. Emerging evidence supports distinct roles of progesterone and its influence on the pathogenesis of these diseases. Progesterone antagonizes estrogen-driven growth in the endometrium, and insufficient progesterone action strikingly increases the risk of endometrial cancer. In endometriosis, eutopic and ectopic tissues do not respond sufficiently to progesterone and are considered to be progesterone-resistant, which contributes to proliferation and survival. In uterine fibroids, progesterone promotes growth by increasing proliferation, cellular hypertrophy, and deposition of extracellular matrix. In normal mammary tissue and breast cancer, progesterone is pro-proliferative and carcinogenic. A key difference between these tissues that could explain the diverse effects of progesterone is the paracrine interactions of PR-expressing stroma and epithelium. Normal endometrium is a mucosa containing large quantities of distinct stromal cells with abundant PR, which influences epithelial cell proliferation and differentiation and protects against carcinogenic transformation. In contrast, the primary target cells of progesterone in the breast and fibroids are the mammary epithelial cells and the leiomyoma cells, which lack specifically organized stromal components with significant PR expression. This review provides a unifying perspective for the diverse effects of progesterone across human tissues and diseases.

Diverse effects of phytoestrogens on the reproductive performance: cow as a model

Phytoestrogens, polyphenolic compounds derived from plants, are more and more common constituents of human and animal diets. In most of the cases, these chemicals are much less potent than endogenous estrogens but exert their biological effects via similar mechanisms of action. The most common source of phytoestrogen exposure to humans as well as ruminants is soybean-derived foods that are rich in the isoflavones genistein and daidzein being metabolized in the digestive tract to even more potent metabolites-para-ethyl-phenol and equol. Phytoestrogens have recently come into considerable interest due to the increasing information on their adverse effects in human and animal reproduction, increasing the number of people substituting animal proteins with plant-derived proteins. Finally, the soybean becomes the main source of protein in animal fodder because of an absolute prohibition of bone meal use for animal feeding in 1995 in Europe. The review describes how exposure of soybean-derived phytoestrogens can have adverse effects on reproductive performance in female adults.

Estrogen Regulates MAPK-Related Genes through Genomic and Nongenomic Interactions between IGF-I Receptor Tyrosine Kinase and Estrogen Receptor-Alpha Signaling Pathways in Human Uterine Leiomyoma Cells

Estrogen and growth factors play a major role in uterine leiomyoma (UtLM) growth possibly through interactions of receptor tyrosine kinases (RTKs) and estrogen receptor-alpha (ERα) signaling. We determined the genomic and nongenomic effects of 17β-estradiol (E₂) on IGF-IR/MAPKp44/42 signaling and gene expression in human UtLM cells with intact or silenced IGF-IR. Analysis by RT² Profiler PCR-array showed genes involved in IGF-IR/MAPK signaling were upregulated in UtLM cells by E₂ including cyclin D kinases, MAPKs, and MAPK kinases; RTK signaling mediator, GRB2; transcriptional factors ELK1 and E2F1; CCNB2 involved in cell cycle progression, proliferation, and survival; and COL1A1 associated with collagen synthesis. Silencing (si)IGF-IR attenuated the above effects and resulted in upregulation of different genes, such as transcriptional factor ETS2; the tyrosine kinase receptor, EGFR; and DLK1 involved in fibrosis. E₂ rapidly activated IGF-IR/MAPKp44/42 signaling nongenomically and induced phosphorylation of ERα at ser118 in cells with a functional IGF-IR versus those without. E₂ also upregulated IGF-I gene and protein expression through a prolonged genomic event. These results suggest a pivotal role of IGF-IR and possibly other RTKs in mediating genomic and nongenomic hormone receptor interactions and signaling in fibroids and provide novel genes and targets for future intervention and prevention strategies.

The role of progesterone signaling in the pathogenesis of uterine leiomyoma

Uterine leiomyomas are benign tumors that originate from the myometrium. Evidence points to ovarian steroid hormones, in particular, progesterone as major promoters of leiomyoma development and growth. While progesterone action in leiomyomas involves the classical nuclear receptor effects on gene regulation, there is growing evidence that signaling pathways are directly activated by the progesterone receptor (PR) and that PR can interact with growth factor signaling systems to promote proliferation and survival of leiomyomas. Studies investigating the genomic and non-genomic actions of PR and its role in leiomyoma growth are summarized here. Studies testing various selective progesterone receptor modulators for the treatment of leiomyomas are also highlighted. An increased understanding of the mechanisms associated with progesterone-driven growth of leiomyomas is critical in order to develop more efficient and targeted therapies for this prevalent disease.

PI3K-Akt-mTOR and MAPK signaling pathways in polycystic ovarian syndrome, uterine leiomyomas and endometriosis: an update

PI3K-Akt-mTOR and MAP kinase are two important cell signaling pathways that are activated by steroid hormones and growth factors leading to cellular events including gene expression, cell proliferation and survival. These pathways are considered as an attractive target for the development of novel anticancer molecules, and selective inhibitors specifically targeting different components of these cascades have been developed. This review summarizes the current available knowledge on the PI3K-Akt-mTOR and MAPK pathways and their targeting in estrogen-dependent benign gynecological disorders viz. polycystic ovarian syndrome, uterine leiomyomas and endometriosis, which are a significant cause of high morbidity in women of reproductive age group. Increasing knowledge about the role of the two growth regulatory pathways in the pathogenesis of these disorders may give the opportunity to use specific signal transduction inhibitors for management of these patients in future.

Growth factors and myometrium: biological effects in uterine fibroid and possible clinical implications

BACKGROUND

Growth factors are proteins secreted by a number of cell types that are capable of modulating cellular growth, proliferation and cellular differentiation. It is well accepted that uterine cellular events such as proliferation and differentiation are regulated by sex steroids and their actions in target tissues are mediated by local production of growth factors acting through paracrine and/or autocrine mechanisms. Myometrial mass is ultimately modified in pregnancy as well as in tumour conditions such as leiomyoma and leiomyosarcoma. Leiomyomas, also known as fibroids, are benign tumours of the uterus, considered to be one of the most frequent causes of infertility in reproductive years in women.

METHODS

For this review, we searched the database MEDLINE and Google Scholar for articles with content related to growth factors acting on myometrium; the findings are hereby reviewed and discussed.

RESULTS

Different growth factors such as epidermal growth factor (EGF), transforming growth factor-α (TGF-α), heparin-binding EGF (HB-EGF), acidic fibroblast growth factor (aFGF), basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), insulin-like growth factor (IGF), platelet-derived growth factor (PDGF) and TGF-β perform actions in myometrium and in leiomyomas. In addition to these growth factors, activin and myostatin have been recently identified in myometrium and leiomyoma.

CONCLUSIONS

Growth factors play an important role in the mechanisms involved in myometrial patho-physiology.

Comparative studies on the interaction of genistein, 8-chlorogenistein, and 3',8-dichlorogenistein with bovine serum albumin

Chlorination can significantly enhance the antioxidant and antitumor activity of genistein. In this paper, genistein, 8-chlorogenistein, and 3',8-dichlorogenistein were selected to investigate the binding to bovine serum albumin (BSA) using fluorescence spectroscopy and circular dichroism (CD). The results showed that chlorination, especially at position 3', had significant effects on the binding constant value of chlorinated genistein derivatives to BSA; however, the binding site and the binding number were slightly affected. The thermodynamic parameters indicated that hydrophobic and electrostatic forces played important roles in the binding process and the enhanced binding affinity mainly associated with the increase of the hydrophobicity caused by the chlorine atom substitution. Furthermore, the CD data demonstrated that the conformation of BSA was slightly altered in the presence of genistein, 8-chlorogenistein, and 3',8-dichlorogenistein, with different reduced α-helix contents. The results obtained herein will be of biological significance in toxicology investigation and genistein derivative drug design.

Multiple-targeting and conformational selection in the estrogen receptor: computation and experiment

Conformational selection is a primary mechanism in biomolecular recognition. The conformational ensemble may determine the ability of a drug to compete with a native ligand for a receptor target. Traditional docking procedures which use one or few protein structures are limited and may not be able to represent a complex competition among closely related protein receptors in agonist and antagonist ensembles. Here, we test a protocol aimed at selecting a drug candidate based on its ability to synergistically bind to distinct conformational states. We demonstrate, for the case of estrogen receptor α (ERα) and estrogen receptor β (ERβ), that the functional outcome of ligand binding can be inferred from its ability to simultaneously bind both ERα and ERβ in agonist and antagonist conformations as calculated docking scores. Combining a conformational selection method with an experimental reporter gene system in yeast, we propose that several phytoestrogens can be novel estrogen receptor β selective agonists. Our work proposes a computational protocol to select estrogen receptor subtype selective agonists. Compared with other models, present method gives the best prediction in ligands' function.

Risks and benefits of dietary isoflavones for cancer

A high intake of fruits and vegetables is associated with a lower risk of cancer. In this context, considerable attention is paid to Asian populations who consume high amounts of soy and soy-derived isoflavones, and have a lower risk for several cancer types such as breast and prostate cancers than populations in Western countries. Hence, interest focuses on soyfoods, soy products, and soy ingredients such as isoflavones with regard to their possible beneficial effects that were observed in numerous experiments and studies. The outcomes of the studies are not always conclusive, are often contradictory depending on the experimental conditions, and are, therefore, difficult to interpret. Isoflavone research revealed not only beneficial but also adverse effects, for instance, on the reproductive system. This is also the case with tumor-promoting effects on, for example, breast tissue. Isoflavone extracts and supplements are often used for the treatment of menopausal symptoms and for the prevention of age-associated conditions such as cardiovascular diseases and osteoporosis in postmenopausal women. In relation to this, questions about the effectiveness and safety of isoflavones have to be clarified. Moreover, there are concerns about the maternal consumption of isoflavones due to the development of leukemia in infants. In contrast, men may benefit from the intake of isoflavones with regard to reducing the risk of prostate cancer. Therefore, this review examines the risks but also the benefits of isoflavones with regard to various kinds of cancer, which can be derived from animal and human studies as well as from in vitro experiments.

Protective effects of prepubertal genistein exposure on mammary tumorigenesis are dependent on BRCA1 expression

This study investigated whether prepubertal dietary exposure to genistein reduces mammary tumorigenesis by upregulating Brca1 expression in mice. Heterozygous Brca1(+/-) mice and their wild-type (WT) littermates were fed control AIN93G diet or 500 ppm genistein-supplemented AIN93G diet from postnatal day (PND) 15 to PND30 and then switched to AIN93G diet. Prepubertal dietary exposure to genistein reduced 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary incidence (P = 0.029) and aggressiveness of the tumors (P < 0.001) in the WT mice and upregulated the expression of Brca1 in their mammary glands (P = 0.04). In contrast, prepubertal genistein diet neither significantly reduced mammary tumorigenesis or tumor aggressivity nor increased Brca1 mRNA expression in the Brca1(+/-) mice. These results may be related to the opposing effects of prepubertal genistein diet on the expression of Rankl and CK5/CK18 ratio (marker of luminal epithelial cell differentiation) in the mammary gland and estrogen receptor (ER-α) and progesterone receptor (PgR) protein levels in the mammary tumor: these all were reduced in the WT mice or increased in Brca1(+/-) mice. Both the WT and Brca1(+/-) mice exhibited reduced levels of amphiregulin, CK5, and CK18, delayed ductal elongation and a reduction in terminal end bud number in the normal mammary gland, and reduced HER-2 protein levels in the mammary tumors; however, these effects were not sufficient to significantly reduce mammary tumorigenesis in Brca1(+/-) mice. Our results show that upregulation of Brca1 may be required for prepubertal dietary genistein exposure to reduce later mammary tumorigenesis, perhaps because in the absence of this upregulation, mice do not exhibit genistein-induced downregulation of ER-α, PgR, and Rankl.

Progesterone is essential for maintenance and growth of uterine leiomyoma

Uterine leiomyomata (ULs) represent the most common tumor in women and can cause abnormal uterine bleeding, large pelvic masses, and recurrent pregnancy loss. Although the dependency of UL growth on ovarian steroids is well established, the relative contributions of 17beta-estradiol and progesterone are yet to be clarified. Conventionally, estradiol has been considered the primary stimulus for UL growth, and studies with cell culture and animal models support this concept. In contrast, no research model has clearly demonstrated a requirement of progesterone in UL growth despite accumulating clinical evidence for the essential role of progesterone in this tumor. To elucidate the functions of ovarian steroids in UL, we established a xenograft model reflecting characteristics of these tumors by grafting human UL tissue beneath the renal capsule of immunodeficient mice. Leiomyoma xenografts increased in size in response to estradiol plus progesterone through cell proliferation and volume increase in cellular and extracellular components. The xenograft growth induced by estradiol plus progesterone was blocked by the antiprogestin RU486. Furthermore, the volume of established UL xenografts decreased significantly after progesterone withdrawal. Surprisingly, treatment with estradiol alone neither increased nor maintained the tumor size. Although not mitogenic by itself, estradiol induced expression of progesterone receptor and supported progesterone action on leiomyoma xenografts. Taken together, our findings define that volume maintenance and growth of human UL are progesterone dependent.