Estrogen stimulated migration and invasion of estrogen receptor-negative breast cancer cells involves an ezrin-dependent crosstalk between G protein-coupled receptor 30 and estrogen receptor beta signaling

Comprehensive understanding of the role of GPER in estrogen receptor-alpha negative breast cancer

G protein-coupled estrogen receptor (GPER) plays a prominent role in facilitating the rapid, non-genomic signaling of estrogens in breast cancer cells. Herein, a comprehensive overview of the role of GPER in ER-ɑ-negative breast cancer is provided. Activation of GPER affected proliferation, metastasis and epithelial mesenchymal transition in ER-ɑ negative breast cancer cells. Clinical studies have demonstrated that GPER positivity was strongly correlated with larger tumor size and advanced clinical stage, suggesting that GPER/ERK signaling may play a role in promoting tumor progression. Strong evidence existed that environmental contaminants like bisphenol A have a carcinogenic potential mediated by GPER activation. The complexity of the cross talk between GPER and other receptors including ER-β, ER-α36, Estrogen-related receptor α (ERRα) and androgen receptor has been discussed. The potential utility of small molecules and phytoestrogens targeting GPER, adds valuable insights into its therapeutic potential. This review holds promises in advancing our understanding of GPER role in ER-ɑ-negative breast cancer. Overall, the consequences of GPER activation are still an area of active research and the implication are not entirely clear.

UDP-6-glucose dehydrogenase in hormonally responsive breast cancers

Survival for metastatic breast cancer is low and thus, continued efforts to treat and prevent metastatic progression are critical. Estrogen is shown to promote aggressive phenotypes in multiple cancer models irrespective of estrogen receptor (ER) status. Similarly, UDP-Glucose 6-dehydrogenase (UGDH) a ubiquitously expressed enzyme involved in extracellular matrix precursors, as well as hormone processing increases migratory and invasive properties in cancer models. While the role of UGDH in cellular migration is defined, how it intersects with and impacts hormone signaling pathways associated with tumor progression in metastatic breast cancer has not been explored. Here we demonstrate that UGDH knockdown blunts estrogen-induced tumorigenic phenotypes (migration and colony formation) in ER+ and ER- breast cancer in vitro. Knockdown of UGDH also inhibits extravasation of ER- breast cancer ex vivo, primary tumor growth and animal survival in vivo in both ER+ and ER- breast cancer. We also use single cell RNA-sequencing to demonstrate that our findings translate to a human breast cancer clinical specimen. Our findings support the role of estrogen and UGDH in breast cancer progression provide a foundation for future studies to evaluate the role of UGDH in therapeutic resistance to improve outcomes and survival for breast cancer patients.

Current progress and prospects for G protein-coupled estrogen receptor in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a biologically and clinically heterogeneous disease. The G protein-coupled estrogen receptor (GPER) plays a crucial role in mediating the effect of estrogen and estrogen-like compounds in TNBC cells. Compared with other subtypes, GPER has a higher expression in TNBC. The GPER mechanisms have been thoroughly characterized and analyzed in estrogen receptor α (ERα) positive breast cancer, but not in TNBC. Our previous work revealed that a higher expression of GPER mRNA indicates a better prognosis for ERα-positive breast cancer; however, its effects in TNBC differ. Whether GPER could serve as a predictive prognostic marker or therapeutic target for TNBC remains unclear. In this review, we provide a detailed introduction to the subcellular localization of GPER, the different effects of various ligands, and the interactions between GPER and closely associated factors in TNBC. We focused on the internal molecular mechanisms specific to TNBC and thoroughly explored the role of GPER in promoting tumor development. We also discussed the interaction of GPER with specific cytokines and chemokines, and the relationship between GPER and immune evasion. Additionally, we discussed the feasibility of using GPER as a therapeutic target in the context of existing studies. This comprehensive review highlights the effects of GPER on TNBC, providing a framework and directions for future research.

Steroid hormone-mediated regulation of sexual and aggressive behaviour by non-genomic signalling

Sex and aggression are well studied examples of social behaviours that are common to most animals and are mediated by an evolutionary conserved group of interconnected nuclei in the brain called the social behaviour network. Though glucocorticoids and in particular estrogen regulate these social behaviours, their effects in the brain are generally thought to be mediated by genomic signalling, a slow transcriptional regulation mediated by nuclear hormone receptors. In the last decade or so, there has been renewed interest in understanding the physiological significance of rapid, non-genomic signalling mediated by steroids. Though the identity of the membrane hormone receptors that mediate this signalling is not clearly understood and appears to be different in different cell types, such signalling contributes to physiologically relevant behaviours such as sex and aggression. In this short review, we summarise the evidence for this phenomenon in the rodent, by focusing on estrogen and to some extent, glucocorticoid signalling. The use of these signals, in relation to genomic signalling is manifold and ranges from potentiation of transcription to the possible transduction of environmental signals.

Anticancer or carcinogenic? The role of estrogen receptor β in breast cancer progression

Estrogen receptor β (ERβ) is closely related to breast cancer (BC) progression. Traditional concepts regard ERβ as a tumor suppressor. As studies show the carcinogenic effect of ERβ, some people have come to a new conclusion that ERβ serves as a tumor suppressor in estrogen receptor α (ERα)-positive breast cancer, while it is a carcinogen in ERα-negative breast cancer. However, we re-examine the role of ERβ and find this conclusion to be misleading based on the last decade's research. A large number of studies have shown that ERβ plays an anticancer role in both ERα-positive and ERα-negative breast cancers, and its carcinogenicity does not depend solely on the presence of ERα. Herein, we review the anticancer and oncogenic effects of ERβ on breast cancer progression in the past ten years, discuss the mechanism respectively, analyze the main reasons for the inconsistency and update ERβ selective ligand library. We believe a detailed and continuously updated review will help correct the one-sided understanding of ERβ, promoting ERβ-targeted breast cancer therapy.

The Expression of GPR30 in Iron-Overloaded Atypical Ovarian Epithelium and Ectopic Endometrium Is Closely Correlated with Transferrin Receptor and Pi3K

Background. The mechanism of atypical hyperplasia of the ovarian epithelium and ectopic endometrium caused by iron overload remains unclear. Accordingly, we investigated possible effects on the human ovarian ectopic endometrium and ovarian epithelium by producing a high-iron environment with rat ovaries. Objective. Human ovarian ectopic endometrium with atypical hyperplasia was collected, and the correlation between transferrin receptor GPR30 and Pi3K protein expression was studied by immunohistochemistry staining. Twenty SPF Sprague–Dawley female rats were microinjected with iron into one side of the ovary once a month, and the other ovary was used as the control. After 10 months of microinjection, the iron histological analysis was examined by Prussian blue staining, and ovarian endometrium morphology was assessed by HE staining. Abnormal lesion changes were measured by Pi3K staining. Evaluation of GPR30 was performed using reverse transcription PCR (RT-PCR) and western blotting, and the interrelationship between GPR30 and Pi3K was also assayed. Results. GPR30 was significantly increased and correlated with the transferrin receptor and Pi3K in atypical human ovarian ectopic endometrium. Iron overload was confirmed in the 20 microinjected ovary cortexes, epithelial hyperplasia was observed in 12 ovaries, and papillary atypical hyperplasia was noted in eight ovaries. The RNA and protein levels of GPR30 were significantly increased in atypical hyperplasia compared to hyperplasia tissue samples. A positive relationship between GPR30 and Pi3K was found ( $P=0.001$ ). Conclusion. The results suggest that persistent iron exposure may be a potential stimulus for ovarian endometriosis with atypical changes, and the abnormal increase in the new estrogen receptor GPR30 is closely related to this process.

27-Hydroxycholesterol Binds GPER and Induces Progression of Estrogen Receptor-Negative Breast Cancer

Simple Summary

Breast cancer is the most common cancer in women, and there is a known link between high cholesterol levels and breast cancer. However, how cholesterol impacts breast cancer is poorly understood, particularly in the case of an aggressive form of cancer known as estrogen receptor negative breast cancer. Using cells in culture and models of breast tumors in mice, we have determined that an abundant metabolite of cholesterol known as 27-hydroxycholesterol stimulates estrogen receptor negative breast cancer growth. We have also determined how 27-hydroxycholesterol stimulates the growth, identifying a new mechanism of action of 27-hydroxycholesterol. These new findings may explain the link between high cholesterol and estrogen receptor negative breast cancer, and they may lead to the development of new therapies for a type of breast cancer that presently lacks specific treatments.

Abstract

Cholesterol affects the proliferation of breast cancer (BC) and in particular of estrogen receptor-negative (ER−) BC. Cholesterol is converted to 27-hydroxycholesterol (27HC), which promotes the growth of ER+ BC. Potentially, 27HC can be involved in cholesterol-dependent ER− BC proliferation. Stable MDA-MB-231 silenced clones for CYP7B1 (27HC metabolizing enzyme) show an increased basal proliferation rate, which is not observed in the presence of lipoprotein-deprived serum. Furthermore, the treatment of SKBR3, MDA-MB-231 and MDA-MB-468 with 27HC increased cell proliferation that was prevented by G15, a selective G Protein-Coupled Estrogen Receptor (GPER) inhibitor, suggested this receptor to be a potential 27HC target. Binding experiments demonstrate that 27HC is a new ligand for GPER. We show that ERK1/2 and NFκB are part of the 27HC/GPER pathway. The stable silencing of GPER prevents NFκB activation and reduces basal and 27HC-dependent tumor growth. Additionally, conditioned medium from ER− BC cells treated with 27HC promotes tube formation, which does not occur with CM from GPER silenced cells. Collectively, these data demonstrate that cholesterol conversion into 27HC promotes ER− BC growth and progression, and the expression of GPER is required for its effects.

Elucidating the estrogen-like effects and biocompatibility of the herbal components in the Qing' E formula

ETHNOPHARMACOLOGICAL RELEVANCE

The Qing' E Formula (QEF) is a compound preparation that was originally recorded in the 'Prescriptions of the Bureau of Taiping People's Welfare Pharmacy' during the Song Dynasty (10th century CE). It consists of four Chinese medicinal herbs, Eucommiae Cortex (Eucommia ulmoides), Psoraleae Fructus (Psoralea corylifolium), Juglandis Semen (Juglans regia), and Garlic Rhizoma. According to traditional Chinese medicine (TCM), QEF has the ability to tonify the kidney and strengthen muscle and bone. According to the 'kidney governing bone' theory in TCM, QEF is also used to treat the symptoms of climacteric syndrome, especially osteoporosis caused by reduced production of estrogen during the perimenopausal period; however, the therapeutic roles of the individual components of the QEF and their compatibility within the formula has not been investigated.

AIM OF THE STUDY

In this study, the compatibility mechanism and estrogen-like action properties of the four herbal components in the QEF was elucidated according to the organizing principle of Chinese medicine formulas using both in vitro and in vivo models.

MATERIALS AND METHODS

The estrogen-like effects of QEF and its herbal components were investigated in MCF7 and HEK293 cells as well as ovariectomized (OVX) rats. The estrogen-like effects of the QEF and its components were analyzed in vitro using Cell Counting Kit-8 and Luciferase reporter gene assays. In the in vivo studies, the blood plasma levels of hormones, lipids, neurotransmitters, aromatase, superoxide dismutase (SOD), and malondialdehyde (MDA) were measured through enzyme-linked immunosorbent assays (ELISAs). The histological morphologies of the target organs after exposure to QEF were investigated by HE staining and immunohistochemical methods. The expression levels of estrogen pathway-related proteins and genes in the OVX rats were measured by Western blotting and real time quantitative PCR (RT-qPCR), respectively.

RESULTS

The in vitro results showed that the QEF, Eucommia (EC) and Psoralea (PF) promoted the proliferation of MCF-7 cells and upregulated the expression of ERα, ERβ and pS2 genes in the MCF-7 cells. Notably, the QEF demonstrated the most active estrogen-like effects compared to the individual ingredients. The in vivo results showed that the QEF, EC, and PF increased the uterine coefficient, upregulated the expression of both ERs (ERα and ERβ) in the uterus, and increased blood serum hormone levels. QEF and its individual components ameliorated menopausal-derived lipid metabolism dysfunction, increased neurotransmitter production by stimulating the adrenal glands, enhanced the antioxidant activity in the serum by increasing the concentration of SOD, reversed ovariectomy-derived atrophy in the uterus, and reduced the weight gain associated with estrogen reduction in the OVX rats. The QEF also antagonize the loss of appetite of OVX animals caused by feeding Psoralea alone, which could explain the compatibility mechanism of Qing' E Formula with reducing toxicity and increasing efficiency.

CONCLUSIONS

The estrogen-like effects of Eucommia and Psoralea were mainly mediated through activation of ERα and ERβ. The phytoestrogen components regulated hormone production and the expression of related proteins and genes, which indicated that these components exhibited estrogen-like therapeutic effects. However, the QEF showed the greatest estrogen-like effects compared to the individual components. Overall, this corroborated the therapeutic prowess of the QEF and clarified the pharmacodynamic interactions between the different components extracts in the QEF.

Estrogens and Progestogens in Triple Negative Breast Cancer: Do They Harm?

Triple-negative breast cancers (TNBC) occur more frequently in younger women and do not express estrogen receptor (ER) nor progesterone receptor (PR), and are therefore often considered hormone-insensitive. Treatment of premenopausal TNBC patients almost always includes chemotherapy, which may lead to premature ovarian insufficiency (POI) and can severely impact quality of life. Hormone replacement therapy (HRT) is contraindicated for patients with a history of hormone-sensitive breast cancer, but the data on safety for TNBC patients is inconclusive, with a few randomized trials showing increased risk-ratios with wide confidence intervals for recurrence after HRT. Here, we review the literature on alternative pathways from the classical ER/PR. We find that for both estrogens and progestogens, potential alternatives exist for exerting their effects on TNBC, ranging from receptor conversion, to alternative receptors capable of binding estrogens, as well as paracrine pathways, such as RANK/RANKL, which can cause progestogens to indirectly stimulate growth and metastasis of TNBC. Finally, HRT may also influence other hormones, such as androgens, and their effects on TNBCs expressing androgen receptors (AR). Concluding, the assumption that TNBC is completely hormone-insensitive is incorrect. However, the direction of the effects of the alternative pathways is not always clear, and will need to be investigated further.

Insights into the Behavior of Triple-Negative MDA-MB-231 Breast Carcinoma Cells Following the Treatment with 17β-Ethinylestradiol and Levonorgestrel

Oral contraceptives (OCs) are widely used due to their efficiency in preventing unplanned pregnancies and treating several human illnesses. Despite their medical value, the toxicity of OCs remains a public concern. Previous studies indicate the carcinogenic potential of synthetic sex hormones and their link to the development and progression of hormone-dependent malignancies such as breast cancer. However, little is known about their influence on the evolution of triple-negative breast carcinoma (TNBC), a malignancy defined by the absence of estrogen, progesterone, and HER2 receptors. This study reveals that the active ingredients of modern OCs, 17β-Ethinylestradiol, Levonorgestrel, and their combination induce differential effects in MDA-MB-231 TNBC cells. The most relevant behavioral changes occurred after the 24 h treatment with 17β-Ethinylestradiol, summarized as follows: (i) decreased cell viability (64.32% at 10 µM); (ii) cell roundness and loss of confluence; (iii) apoptotic aspect of cell nuclei (fragmentation, membrane blebbing); and (iv) inhibited cell migration, suggesting a potential anticancer effect. Conversely, Levonorgestrel was generally associated with a proliferative activity. The association of the two OCs exerted similar effects as 17β-Ethinylestradiol but was less effective. Further studies are necessary to elucidate the hormones' cytotoxic mechanism of action on TNBC cells.

In vitro Non-Small Cell Lung Cancer Inhibitory Effect by New Diphenylethane Isolated From Stems and Leaves of Dioscorea oppositifolia L. via ERβ-STAT3 Pathway

Lung cancer is the most leading cause of cancer mortality throughout the world, of which about 85% cases comprise the non-small cell lung cancer (NSCLC). Estrogen and estrogen receptors are known to be involved in the pathogenesis and development of lung cancer. Dioscorea oppositifolia L. is a traditional Chinese medicine and a nutritious food, and can be an excellent candidate as an anti-cancer agent owing to its estrogen-like effects. However, the stems and leaves of D. oppositifolia L. are piled up in the field as a waste, causing environmental pollution and waste of resources. In the present study, a new diphenylethane (D1) was isolated from the stems and leaves of D. oppositifolia L. It was observed that D1 reduced the cell viability, migration, energy metabolism, and induced apoptosis in the A549 cells. Mechanistic studies showed that D1 reduced the STAT3 nuclear localization and downregulated the expression of the STAT3 target genes like Mcl-1, Bcl-xL and MMP-2 that are involved in the cell survival and mobility. Moreover, our results indicated that D1 exhibited estrogenic activities mediated by ERβ, and antagonising ERβ decreased the cytotoxic effect of D1 in A549 cells. In addition, inhibition of the nuclear translocation of STAT3 did not interfere with the binding of D1 and ERβ. However, after antagonizing ERβ, the nuclear translocation of STAT3 increased, thereby demonstrating that STAT3 was the downstream signaling molecule of ERβ. In conclusion, the D1 mediated anti-NSCLC in vitro effects or at least in part can be attributed to the ERβ-STAT3 signaling. Our findings suggest the role of D1 in treating NSCLC on a molecular level, and can help to improve the comprehensive utilization rate of D. oppositifolia L.

The Metabolic Mechanisms of Breast Cancer Metastasis

Breast cancer is one of the most common malignancy among women worldwide. Metastasis is mainly responsible for treatment failure and is the cause of most breast cancer deaths. The role of metabolism in the progression and metastasis of breast cancer is gradually being emphasized. However, the regulatory mechanisms that conduce to cancer metastasis by metabolic reprogramming in breast cancer have not been expounded. Breast cancer cells exhibit different metabolic phenotypes depending on their molecular subtypes and metastatic sites. Both intrinsic factors, such as MYC amplification, PIK3CA, and TP53 mutations, and extrinsic factors, such as hypoxia, oxidative stress, and acidosis, contribute to different metabolic reprogramming phenotypes in metastatic breast cancers. Understanding the metabolic mechanisms underlying breast cancer metastasis will provide important clues to develop novel therapeutic approaches for treatment of metastatic breast cancer.

Involvement of the ERK/HIF-1α/EMT Pathway in XCL1-Induced Migration of MDA-MB-231 and SK-BR-3 Breast Cancer Cells

Chemokine–receptor interactions play multiple roles in cancer progression. It was reported that the overexpression of X-C motif chemokine receptor 1 (XCR1), a specific receptor for chemokine X-C motif chemokine ligand 1 (XCL1), stimulates the migration of MDA-MB-231 triple-negative breast cancer cells. However, the exact mechanisms of this process remain to be elucidated. Our study found that XCL1 treatment markedly enhanced MDA-MB-231 cell migration. Additionally, XCL1 treatment enhanced epithelial–mesenchymal transition (EMT) of MDA-MB-231 cells via E-cadherin downregulation and upregulation of N-cadherin and vimentin as well as increases in β-catenin nucleus translocation. Furthermore, XCL1 enhanced the expression of hypoxia-inducible factor-1α (HIF-1α) and phosphorylation of extracellular signal-regulated kinase (ERK) 1/2. Notably, the effects of XCL1 on cell migration and intracellular signaling were negated by knockdown of XCR1 using siRNA, confirming XCR1-mediated actions. Treating MDA-MB-231 cells with U0126, a specific mitogen-activated protein kinase kinase (MEK) 1/2 inhibitor, blocked XCL1-induced HIF-1α accumulation and cell migration. The effect of XCL1 on cell migration was also evaluated in ER^-/HER2⁺ SK-BR-3 cells. XCL1 also promoted cell migration, EMT induction, HIF-1α accumulation, and ERK phosphorylation in SK-BR-3 cells. While XCL1 did not exhibit any significant impact on the matrix metalloproteinase (MMP)-2 and -9 expressions in MDA-MB-231 cells, it increased the expression of these enzymes in SK-BR-3 cells. Collectively, our results demonstrate that activation of the ERK/HIF-1α/EMT pathway is involved in the XCL1-induced migration of both MDA-MB-231 and SK-BR-3 breast cancer cells. Based on our findings, the XCL1–XCR1 interaction and its associated signaling molecules may serve as specific targets for the prevention of breast cancer cell migration and metastasis.

Quercetin exerts bidirectional regulation effects on the efficacy of tamoxifen in estrogen receptor-positive breast cancer therapy: An in vitro study

Tamoxifen was widely applied in the therapy of estrogen receptor (ER)-positive breast cancer. With the purpose of determining the potential impacts of quercetin on its effectiveness, MCF-7 cells were selected as the in vitro model and several cellular biological behaviors (ie, cell proliferation, migration, invasion, cycle, apoptosis, and oxidative stress) were investigated. As results, quercetin showed contrasting dose-response to cellular behaviors dependent on the ROS-regulated p53 signaling pathways. In detail, quercetin promoted cell proliferation and inhibited cell apoptosis at low concentrations, whereas high-concentration resulted in apoptosis induction. Moreover, quercetin at a low concentration significantly inhibited tamoxifen-induced antiproliferation in MCF-7 cells, whereas high concentrations enhanced cell apoptosis in a synergetic manner. The real-time quantitative polymerase chain reaction analysis further implied that quercetin exerted its dual roles in tamoxifen-induced antiproliferative effects by regulated the gene expression involved in cell metastasis, cycle, and apoptosis through the ER pathways. Our present study provides a considerable support to the combination of quercetin and tamoxifen on human ER-positive breast carcinoma management.

Estrogen-Related Receptor α (ERRα) and G Protein-Coupled Estrogen Receptor (GPER) Synergistically Indicate Poor Prognosis in Patients with Triple-Negative Breast Cancer

Purpose

The present study aims to demonstrate the correlation between estrogen-related receptor α (ERRα) and G protein-coupled estrogen receptor (GPER) expression and its predictive role in the prognosis of patients with triple-negative breast cancer (TNBC).

Methods

A retrospective review of 199 cases of TNBC was conducted to assess the GPER and ERRα expression, and its clinicopathologic and prognostic implications. Subsequently, the effects of ERRα and GPER on cell viability, migration, and invasion induced by estrogen were also investigated in vitro.

Results

Compared to TNBCs with ERRα low expression, ERRα-high patients exhibited higher nuclear grade, more frequent lymph nodal metastasis, a higher rate of local recurrence, and distant metastasis. Survival analyses revealed that ERRα-high patients had decreased overall survival (OS), local recurrence-free survival (LRFS), and distant disease-free survival (DDFS) than ERRα-low patients. The GPER expression level positively correlated with ERRα (R=0.167, P=0.18), and TNBCs with ERRα-low/GPER-low demonstrated the best survival outcomes among groups. In vitro, E2 significantly enhanced cell viability, migration, and invasion in BT-549 and MDA-MB-231 cell lines, which was associated with the increased expression of ERRα. Moreover, the overexpression of ERRα induced by estrogen and G1 (GPER agonist) was reversed by knocking down of GPER and blocking the MAPK signaling with PD98059 in both cell lines.

Conclusion

Our findings suggest that ERRα and GPER synergistically predict unfavorable prognosis in TNBCs. Mechanically, GPER mediates the upregulation expression of ERRα induced by estrogen and promotes cell viability, migration, and invasion.

The FTO/miR-181b-3p/ARL5B signaling pathway regulates cell migration and invasion in breast cancer

Background

N6‐methyladenosine (m⁶A) RNA modification has been demonstrated to be a significant regulatory process in the progression of various tumors, including breast cancer. Fat mass and obesity‐associated (FTO) enzyme, initially known as the obesity‐related protein, is the first identified m⁶A demethylase. However, the relationship between FTO and breast cancer remains controversial. In this study, we aimed to elucidate the role and clinical significance of FTO in breast cancer and to explore the underlying mechanism.

Methods

We first investigated the expression of FTO in breast cancer cell lines and tissues by quantitative reverse transcription‐PCR (qRT‐PCR), Western blotting, and immunohistochemistry. Wound healing assay and Transwell assay were performed to determine the migration and invasion abilities of SKBR3 and MDA‐MB453 cells with either knockdown or overexpression of FTO. RNA sequencing (RNA‐seq) was conducted to decipher the downstream targets of FTO. qRT‐PCR, luciferase reporter assay, and Western blotting were employed to confirm the existence of the FTO/miR‐181b‐3p/ARL5B axis. The biological function of ADP ribosylation factor like GTPase 5B (ARL5B) in breast cancer cells was evaluated by wound healing assay and Transwell invasion assay.

Results

High FTO expression was observed in human epidermal growth factor receptor 2 (HER2)‐positive breast cancer, predicting advanced progression (tumor size [P < 0.001], nuclear grade [P = 0.001], peritumoral lymphovascular invasion [P < 0.001), lymph node metastasis [P = 0.002], and TNM stage [P = 0.001]) and poor prognosis. Moreover, FTO promoted cell invasion and migration in vitro. Mechanistically, RNA‐seq and further confirmation studies suggested that FTO up‐regulated ARL5B by inhibiting miR‐181b‐3p. We further verified that ARL5B also displayed carcinogenic activity in breast cancer cells.

Conclusion

Our work demonstrated the carcinogenic activity of FTO in promoting the invasion and migration of breast cancer cells via the FTO/miR‐181b‐3p/ARL5B signaling pathway.

The Effects of Trifolium pratense L. Sprouts' Phenolic Compounds on Cell Growth and Migration of MDA-MB-231, MCF-7 and HUVEC Cells

Uncontrolled growth and migration and invasion abilities are common for cancer cells in malignant tumors with low therapeutic effectiveness and high mortality and morbidity. Estrogen receptor β (ERβ), as a member of the nuclear receptor superfamily, shows potent tumor suppressive activities in many cancers. Phytoestrogens’ structural resemblance to 17 β-estradiol allows their binding to ERβ isoform predominantly, and therefore, expression of genes connected with elevated proliferation, motility and invasiveness of cancer cells may be downregulated. Among polyphenolic compounds with phytoestrogenic activity, there are isoflavones from Trifolium pratense L. (red clover) sprouts, containing high amounts of formononetin and biochanin A and their glycosides. To determine the source of the most biologically active isoflavones, we obtained four extracts from sprouts before and after their lactic fermentation and/or β-glucosidase treatment. Our previous results of ITC (isothermal titration calorimetry) modelling and a docking simulation showed clover isoflavones’ affinity to ERβ binding, which may downregulate cancer cell proliferation and migration. Thus, the biological activity of T. pratense sprouts’ extracts was checked under in vitro conditions against highly invasive human breast cancer cell line MDA-MB-231 and non-invasive human breast cancer cell line MCF-7 cells. To compare extracts’ activities acquired for cancer cells with those activities against normal cells, as a third model we choose human umbilical vein endothelial cells (HUVEC), which, due to their migration abilities, are involved in blood vessel formation. Extracts obtained from fermented sprouts at IC₀ dosages were able to inhibit migration of breast cancer cells through their influence on intracellular ROS generation; membrane stiffening; adhesion; regulation of MMP-9, N-cadherin and E-cadherin at transcriptional level; or VEGF secretion. Simultaneously, isolated phenolics revealed no toxicity against normal HUVEC cells. In the manuscript, we proposed a preliminary mechanism accounting for the in vitro activity of Trifolium pratense L. isoflavones. In this manner, T. pratense sprouts, especially after their lactic fermentation, can be considered a potent source of biological active phytoestrogens and a dietary supplement with anti-cancer and anti-invasion properties.

Prognostic role of GPER/Ezrin in triple-negative breast cancer is associated with menopausal status

The role of G protein-coupled estrogen receptor 1 (GPER) signaling, including promotion of Ezrin phosphorylation (which could be activated by estrogen), has not yet been clearly identified in triple-negative breast cancer (TNBC). This study aimed to evaluate the prognostic value of GPER and Ezrin in TNBC patients. Clinicopathologic features including age, menopausal status, tumor size, nuclear grade, lymph node metastasis, AJCC TNM stage, and ER, PR and HER-2 expression were evaluated from 249 TNBC cases. Immunohistochemical staining of GPER and Ezrin was performed on TNBC pathological sections. Kaplan-Meier analyses, as well as logistic regressive and Cox regression model tests were applied to evaluate the prognostic significance between different subgroups. Compared to the GPER-low group, the GPER-high group exhibited higher TNM staging (P = 0.021), more death (P < 0.001), relapse (P < 0.001) and distant events (P < 0.001). Kaplan-Meier analysis showed that GPER-high patients had a decreased OS (P < 0.001), PFS (P < 0.001), LRFS (P < 0.001) and DDFS (P < 0.001) than GPER-low patients. However, these differences in prognosis were not statistically significant in post-menopausal patients (OS, P = 0.8617; PFS, P = 0.1905; LRFS, P = 0.4378; DDFS, P = 0.2538). There was a significant positive correlation between GPER and Ezrin expression level (R = 0.508, P < 0.001) and the effect of Ezrin on survival prognosis corresponded with GPER. Moreover, a multivariable analysis confirmed that GPER and Ezrin level were both significantly associated with poor DDFS (HR: 0.346, 95% CI 0.182-0.658, P = 0.001; HR: 0.320, 95% CI 0.162-0.631, P = 0.001). Thus, overexpression of GPER and Ezrin may contribute to aggressive behavior and indicate unfavorable prognosis in TNBC; this may correspond to an individual's estrogen levels.

Combined Targeting of Estrogen Receptor Alpha and XPO1 Prevent Akt Activation, Remodel Metabolic Pathways and Induce Autophagy to Overcome Tamoxifen Resistance

A majority of breast cancer specific deaths in women with ERα (+) tumors occur due to metastases that are resistant to endocrine therapy. There is a critical need for novel therapeutic approaches to resensitize recurrent ERα (+) tumors to endocrine therapies. The objective of this study was to elucidate mechanisms of improved effectiveness of combined targeting of ERα and the nuclear transport protein XPO1 in overcoming endocrine resistance. Selinexor (SEL), an XPO1 antagonist, has been evaluated in multiple late stage clinical trials in patients with relapsed and /or refractory hematological and solid tumor malignancies. Our transcriptomics analysis showed that 4-Hydroxytamoxifen (4-OHT), SEL alone or their combination induced differential Akt signaling- and metabolism-associated gene expression profiles. Western blot analysis in endocrine resistant cell lines and xenograft models validated differential Akt phosphorylation. Using the Seahorse metabolic profiler, we showed that ERα-XPO1 targeting changed the metabolic phenotype of TAM-resistant breast cancer cells from an energetic to a quiescent profile. This finding demonstrated that combined targeting of XPO1 and ERα rewired the metabolic pathways and shut down both glycolytic and mitochondrial pathways that would eventually lead to autophagy. Remodeling metabolic pathways to regenerate new vulnerabilities in endocrine resistant breast tumors is novel, and given the need for better strategies to improve therapy response in relapsed ERα (+) tumors, our findings show great promise for uncovering the role that ERα-XPO1 crosstalk plays in reducing cancer recurrences.

G-Protein Coupled Estrogen Receptor in Breast Cancer

The G-protein coupled estrogen receptor (GPER), an alternate estrogen receptor (ER) with a structure distinct from the two canonical ERs, being ERα, and ERβ, is expressed in 50% to 60% of breast cancer tissues and has been presumed to be associated with the development of tamoxifen resistance in ERα positive breast cancer. On the other hand, triple-negative breast cancer (TNBC) constitutes 15% to 20% of breast cancers and frequently displays a more aggressive behavior. GPER is prevalent and involved in TNBC and can be a therapeutic target. However, contradictory results exist regarding the function of GPER in breast cancer, proliferative or pro-apoptotic. A better understanding of the GPER, its role in breast cancer, and the interactions with the ER and epidermal growth factor receptor will be beneficial for the disease management and prevention in the future.

Crosstalk between Estrogen Signaling and Breast Cancer Metabolism

Estrogens and estrogen receptors (ERs) regulate metabolism in both normal physiology and in disease. The metabolic characteristics of intrinsic breast cancer subtypes change based on their ER expression. Crosstalk between estrogen signaling elements and several key metabolic regulators alters metabolism in breast cancer cells, and enables tumors to rewire their metabolism to adapt to poor perfusion, transient nutrient deprivation, and increased acidity. This leads to the selection of drug-resistant and metastatic clones. In this review we discuss studies revealing the role of estrogen signaling elements in drug resistance development and metabolic adaptation during breast cancer progression.

Uridine derivatives from the seeds of Lepidium apetalum Willd. and their estrogenic effects

Ten uridine derivatives (lepidiumuridine B-K) were isolated from the seeds of Lepidium apetalum Willd. Lepidiumuridine B-J were previously undescribed compounds, and were structurally characterized using analysis of their NMR and MS data. Lepidiumuridine C, D, I, and J increased cell proliferation and expression of ERα in the MCF-7 cell line. In addition, blockage of ERα completely abolished cell proliferation and expression of ERα in MCF-7 cells, suggesting that the proliferation effects of lepidiumuridine C, D, I, and J were ERα-mediated. The uridine derivatives might belong to undescribed phytoestrogens.

2-Phenylacetamide Isolated from the Seeds of Lepidium apetalum and Its Estrogen-Like Effects In Vitro and In Vivo

The aim of this study was to investigate the estrogen-like effects of 2-phenylacetamide (PA), which is the main compound isolated from the seeds of Lepidium apetalum Willd (LA). Results showed that LA and PA could promote the proliferation of MCF-7 cells. The mouse uterine weight test showed that, LA and PA could increase the uterus index of immature female mice, and the levels of luteinizing hormone (LH) and estrogen (E2). LA could increase the expression of ERα and ERβ, while PA could increase the expression of ERα, ERβ and GPR30 in the uterus and MCF-7 cells. In addition, co-incubation of the estrogen receptor blocker with LA or PA abolished the inductive effect of the proliferation. PA has estrogenic activities and was the material basis of LA that played the estrogenic effect. LA and PA might be used for the treatment of perimenopause syndrome in a novel application.

Pituitary, Gonadal, Thyroid Hormones and Endocrine Disruptors in Pre and Postmenopausal Nigerian Women with ER-, PR- and HER-2-Positive and Negative Breast Cancers

Breast cancer is broadly sub-divided into hormone responsive and non-hormone responsive subtypes. Estradiol has been associated with hormone responsive breast cancers. There is, however, a paucity of information on the role of sex hormones, gonadotropins, and thyroid hormone in non-hormone responsive breast cancer. This study aimed to determine differences in the serum levels of sex hormones, gonadotropins, thyroid hormones, and endocrine disruptors (lead, cadmium, and arsenic) in Nigerian women with hormone responsive and non-hormone responsive breast cancers. Seventy-nine non-pregnant women aged 28–80 years with histologically confirmed breast cancer were recruited, pre-therapy, into this cross-sectional study. They comprised 52 premenopausal women and 27 postmenopausal women recruited from the Surgical Oncology Clinic of the Department of Surgery, University College Hospital, Ibadan. Comparison of biochemical parameters were based on the positivity (+) and negativity (−) of estrogen receptor (ER), progesterone receptor (PR) and human epithelial receptor-2 (HER-2). Estradiol, progesterone, follicle stimulating hormone (FSH), luteinizing hormone (LH), free thyroxine (FT₄), free triiodothyronine (FT₃), and thyroid stimulating hormone (TSH) were determined using enzyme immunoassay (EIA). Serum lead, cadmium and arsenic were determined using atomic absorption spectrophotometry (AAS). Expression of ER, PR and HER2 were determined using immunohistochemistry. Data was analyzed using Mann-Whitney U-test and multiple regression, with p < 0.05 considered as being statistically significant. Estradiol and progesterone were significantly higher in breast cancer participants with ER⁻ and PR⁻ compared with those with ER⁺ and PR⁺ breast cancer (p < 0.05). Follicle stimulating hormone and LH levels were significantly higher in participants with ER⁺ and PR⁺ breast cancer compared with participants with ER⁻ and PR⁻ breast cancer (p < 0.05). Arsenic was inversely related with TSH in premenopausal participants with ER⁻ and PR⁻ (β = −0.305; β = −0.304, respectively). Sex hormones and gonadotropins appear to be involved in the pathogenesis of triple negative and luminal breast cancer, respectively.

GPER1/GPR30 in the brain: Crosstalk with classical estrogen receptors and implications for behavior

The GPER1/GPR30 is a membrane estrogen receptor (mER) that binds 17β-estradiol (17β-E) with high affinity and is thought to play a role in cancer progression and cardiovascular health. Though widespread in the central nervous system, less is known about this receptor's function in the brain. GPER1 has been shown to activate kinase cascades and calcium flux within cells rapidly, thus fitting in with the idea of being a mER that mediates non-genomic signaling by estrogens. Signaling from GPER1 has been shown to improve spatial memory, possibly via release of neurotransmitters and generation of new spines on neurons in the hippocampus. In addition, GPER1 activation contributes to behaviors that denote anxiety and to social behaviors such as social memory and lordosis behavior in mice. In the male hippocampus, GPER1 activation has also been shown to phosphorylate the classical intracellular estrogen receptor (ER)α, suggesting that crosstalk with ERα is important in the display of these behaviors, many of which are absent in ERα-null mice. In this review, we present a number of categories of such crosstalk, using examples from literature. The function of GPER1 as an ERα collaborator or as a mER in different tissues is relevant to understanding both normal physiology and abnormal pathology, mediated by estrogen signaling.

Estrogenic Effects of the Extracts from the Chinese Yam (Dioscorea opposite Thunb.) and Its Effective Compounds in Vitro and in Vivo

BACKGROUND

The aim of this study was to explore the estrogenic effects of the extracts from Chinese yam and its effective compounds.

METHODS

The activity of the yam was investigated by the uterine weight gain of mice and a proliferation assay of breast cancer cell lines (MCF-7 cell); the estrogenic activity was comprehensively evaluated by a serum pharmacology experiment. The levels of estradiol (E2), follicle stimulating hormone (FSH), and luteinizing hormone (LH) were also measured. Western blot analysis and antagonist assays with faslodex (ICI182,780), methylpiperidino-pyrazole (MPP), Delta (9) -tetrahydrocannabinol (THC), and G-15 were used to explore the mechanism of the effects of the yam. To find the effective compounds of the yam which play a role in its estrogen-like effects, we used the same methods to study the effects of adenosine and arbutin.

RESULTS

The Chinese yam and two main compounds, adenosine and arbutin, have estrogen-like effects. The mechanism of the yam which plays a role in its estrogen-like effects was mainly mediated by the estrogen receptors ERα, ERβ, and GPR30; that of adenosine was mainly mediated by estrogen receptors ERα and ERβ, and that of arbutin was mainly mediated by estrogen receptors ERβ and GPR30.

CONCLUSIONS

The Chinese yam has estrogen-like effects; adenosine and arbutin are two of the effective compounds in the yam which play a role in its estrogen-like effects.

Calycosin inhibits the in vitro and in vivo growth of breast cancer cells through WDR7-7-GPR30 Signaling

BACKGROUND

Clinically, breast cancer is generally classified into estrogen receptor-positive (ER+) or estrogen receptor-negative (ER-) subtypes. The phytoestrogen calycosin has been shown to inhibit the proliferation of ER+ cells, which may be mediated by a feedback loop that involves miR-375, RAS dexamethasone-induced 1 (RASD1), and ERα. However, how calycosin acts on ER- breast cancer cells remains unclear.

RESULTS

Here, we show that calycosin inhibited the proliferation of both ER- (MDA-MB-468 and SKBR3) and ER+ breast cancer cells (MCF-7 and T47D) and that these inhibitory effects were associated with the up-regulation of the long non-coding RNA (lncRNA) WDR7-7. For the first time, we demonstrate that the expression of WDR7-7 is reduced in breast cancer cell lines and that the overexpression of WDR7-7 inhibits growth through a mechanism that involves G-protein coupled estrogen receptor 30 (GPR30). Meanwhile, we show that calycosin stimulated the WDR7-7-GPR30 signaling pathway in MCF-7, T47D, MDA-MB-468, and SKBR3 breast cancer cells. In contrast, in MCF10A and GPR30-deficient MDA-MB-231 cells, due to a lack of WDR7-7-GPR30 for activation, calycosin failed to inhibit cell growth. Additionally, in all four GPR30-positive breast cancer lines, calycosin decreased the phosphorylation levels of SRC, EGFR, ERK1/2 and Akt, but the inhibition of WDR7-7 blocked these changes and increased proliferation. In mice bearing MCF-7 or SKBR3 xenografts, tumor growth was inhibited by calycosin, and changes in expression the levels of WDR7-7 and GPR30 in tumor tissues were similar to those in cultured MCF-7 and SKBR3 cells.

CONCLUSIONS

These results suggest the possibility that calycosin inhibited the proliferation of breast cancer cells, at least partially, through WDR7-7-GPR30 signaling, which may explain why calycosin can exert inhibitory effects on ER- breast cancer.

Sphingosine kinase 1 in breast cancer

Breast cancer affects 1 out of 8 women in the US and is the second highest cause of death from cancer for women, leading to considerable research examining the causes, progression, and treatment of breast cancer. Over the last two decades, sphingosine-1-phosphate (S1P), a potent sphingolipid metabolite, has been implicated in many processes important for breast cancer including growth, progression, transformation and metastasis, and is the focus of this review. In particular, one of the kinases that produces S1P, sphingosine kinase 1 (SphK1), has come under increasing scrutiny as it is commonly upregulated in breast cancer cells and has been linked with poorer prognosis and progression, possibly leading to resistance to certain anti-cancer therapies. In this review, we will also discuss preclinical studies of both estrogen receptor (ER) positive as well as triple-negative breast cancer mouse models with inhibitors of SphK1 and other compounds that target the S1P axis and have shown good promise in reducing tumor growth and metastasis. It is hoped that in the future this will lead to development of novel combination approaches for effective treatment of both conventional hormonal therapy-resistant breast cancer and triple-negative breast cancer.

Cross-talk mechanism between endothelial cells and hepatocellular carcinoma cells via growth factors and integrin pathway promotes tumor angiogenesis and cell migration

Tumor angiogenesis plays a central role in the development and metastasis of hepatocellular carcinoma. Cancer cells secrete angiogenic factors to recruit vascular endothelial cells and sustain tumor vascular networks, which facilitate the migration and invasion of cancer cells. Therefore, the cross-talk between vascular endothelial cells and cancer cells is vitally necessary, however, little is known about the cross-talk mechanism of these cells interaction. In the present study, the proliferation, migration, invasion and tube formation of vascular endothelial EA.hy926 cells and hepatocellular carcinoma HepG2 cells were studied by exchanging their culture medium. The time-dependent differences of integrins induced signaling pathway associated with cell migration were investigated. Our results showed that HepG2 cells markedly enhanced the proliferation and migration ability as well as the tube formation of EA.hy926 cells by releasing growth factors. Also, the EA.hy926 cells promoted the proliferation, migration and invasion ability of HepG2 cells. The further analysis demonstrated that the integrins-FAK-Rho GTPases signaling events in both of two cells was activated under conditioned medium, and the signaling molecules in two cell lines showed a different time-dependent expression within 1h. These findings reveal the cross-talk mechanism between the endothelial cells and hepatocellular carcinoma cells, which were expected to find out new ideas for the prevention and treatment of hepatocellular carcinoma.