GPER mediates activation of HIF1α/VEGF signaling by estrogens

GPER deficiency impedes murine myocutaneous revascularization and wound healing

Estrogens regulate numerous physiological and pathological processes, including wide-ranging effects in wound healing. The effects of estrogens are mediated through multiple estrogen receptors (ERs), including the classical nuclear ERs (ERα and ER β ), that typically regulate gene expression, and the 7-transmembrane G protein-coupled estrogen receptor (GPER), that predominantly mediates rapid "non-genomic" signaling. Estrogen modulates the expression of various genes involved in epidermal function and regeneration, inflammation, matrix production, and protease inhibition, all critical to wound healing. Our previous work demonstrated improved myocutaneous wound healing in female mice compared to male mice. In the current study, we employed male and female GPER knockout mice to investigate the role of this estrogen receptor in wound revascularization and tissue viability. Using a murine myocutaneous flap model of graded ischemia, we measured real-time flap perfusion via laser speckle perfusion imaging. We conducted histologic and immunohistochemical analyses to assess skin and muscle viability, microvascular density and vessel morphology. Our results demonstrate that GPER is crucial in wound healing, mediating effects that are both dependent and independent of sex. Lack of GPER expression is associated with increased skin necrosis, reduced flap perfusion and altered vessel morphology. These findings contribute to understanding GPER signaling in wound healing and suggest possible therapeutic opportunities by targeting GPER.

The Role of Estrogen across Multiple Disease Mechanisms

Estrogen is a significant hormone that is involved in a multitude of physiological and pathological processes. In addition to its pivotal role in the reproductive system, estrogen is also implicated in the pathogenesis of a multitude of diseases. Nevertheless, previous research on the role of estrogen in a multitude of diseases, including Alzheimer's disease, depression, cardiovascular disease, diabetes, osteoporosis, gastrointestinal diseases, and estrogen-dependent cancers, has concentrated on a single disease area, resulting in a lack of comprehensive understanding of cross-disease mechanisms. This has brought some challenges to the current treatment methods for these diseases, because estrogen as a potential therapeutic tool has not yet fully developed its potential. Therefore, this review aims to comprehensively explore the mechanism of estrogen in these seven types of diseases. The objective of this study is to describe the relationship between each disease and estrogen, including the ways in which estrogen participates in regulating disease mechanisms, and to outline the efficacy of estrogen in treating these diseases in clinical practice. By studying the role of estrogen in a variety of disease mechanisms, it is hoped that a more accurate theoretical basis and clinical guidance for future treatment strategies will be provided, thus promoting the effective management and treatment of these diseases.

Fasting Blood Glucose-Based Novel Predictors in Detecting Metastases and Predicting Prognosis for Patients with PNENs

OBJECTIVE

To explore three novel fasting blood glucose (FBG)-based novel indicators, including the FBG-to-albumin ratio (FAR), FBG-to-lymphocytes ratio (FLR), and FBG-to-hemoglobin ratio (FHR), in predicting prognosis and detecting metastasis for patients with pancreatic neuroendocrine neoplasms (pNENs) after resection.

MATERIALS AND METHODS

A total of 178 pNENs patients who underwent surgical resection were included in this study. Receiver operating characteristic (ROC) curves were used to evaluate the diagnosis values of FAR, FLR, and FHR, and the cutoff values were obtained for further analyses. Univariate and multivariate analyses were conducted to determine the independent predictors. The Kaplan-Meier method was used to evaluate the progression-free survival (PFS) and overall survival (OS) of the pNENs patients.

RESULTS

The optimal cutoff values of FAR, FLR, and FHR were 0.17, 2.85, and 0.028, respectively. As for PFS, the area under the curve (AUC) was 0.693 for FAR, 0.690 for FLR, and 0.661 for FHR, respectively. The AUC was 0.770, 0.692, and 0.715 accordingly for OS. The groups with lower FAR, FLR, and FHR were significantly associated with prolonged PFS and OS (p < 0.05). In patients with metastasis, the lower FAR group was correlated with significantly longer PFS and OS (p = 0.022 and 0.002, respectively). The FLR was an independent predictor of PFS in pNENs patients, and the FAR was a predictor of OS. FAR was an independent indicator of PFS in patients with metastasis.

CONCLUSIONS

Preoperative FAR, FLR, and FHR are effective in predicting the prognosis of pNEN patients and detecting the synchronous metastases.

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.

Targeting the crosstalk between estrogen receptors and membrane growth factor receptors in breast cancer treatment: Advances and opportunities

Estrogens play a critical role in the initiation and progression of breast cancer. Estrogen receptor (ER)α, ERβ, and G protein-coupled estrogen receptor are the primary receptors for estrogen in breast cancer. These receptors are mainly activated by binding with estrogens. The crosstalk between ERs and membrane growth factor receptors creates additional pathways that amplify the effects of their ligands and promote tumor growth. This crosstalk may cause endocrine therapy resistance in ERα-positive breast cancer. Furthermore, this may explain the resistance to anti-human epidermal growth factor receptor-2 (HER2) treatment in ERα-/HER2-positive breast cancer and chemotherapy resistance in triple-negative breast cancer. Accordingly, it is necessary to understand the complex crosstalk between ERs and growth factor receptors. In this review, we delineate the crosstalk between ERs and membrane growth factor receptors in breast cancer. Moreover, this review highlights the current progress in clinical treatment and discusses how pharmaceuticals target the crosstalk. Lastly, we discuss the current challenges and propose potential solutions regarding the implications of targeting crosstalk via pharmacological inhibition. Overall, the present review provides a landscape of the crosstalk between ERs and membrane growth factor receptors in breast cancer, along with valuable insights for future studies and clinical treatments using a chemotherapy-sparing regimen to improve patient quality of life.

Estetrol/GPER/SERPINB2 transduction signaling inhibits the motility of triple-negative breast cancer cells

BACKGROUND

Estetrol (E4) is a natural estrogen produced by the fetal liver during pregnancy. Due to its favorable safety profile, E4 was recently approved as estrogenic component of a new combined oral contraceptive. E4 is a selective ligand of estrogen receptor (ER)α and ERβ, but its binding to the G Protein-Coupled Estrogen Receptor (GPER) has not been described to date. Therefore, we aimed to explore E4 action in GPER-positive Triple-Negative Breast Cancer (TNBC) cells.

METHODS

The potential interaction between E4 and GPER was investigated by molecular modeling and binding assays. The whole transcriptomic modulation triggered by E4 in TNBC cells via GPER was explored through high-throughput RNA sequencing analyses. Gene and protein expression evaluations as well as migration and invasion assays allowed us to explore the involvement of the GPER-mediated induction of the plasminogen activator inhibitor type 2 (SERPINB2) in the biological responses triggered by E4 in TNBC cells. Furthermore, bioinformatics analysis was aimed at recognizing the biological significance of SERPINB2 in ER-negative breast cancer patients.

RESULTS

After the molecular characterization of the E4 binding capacity to GPER, RNA-seq analysis revealed that the plasminogen activator inhibitor type 2 (SERPINB2) is one of the most up-regulated genes by E4 in a GPER-dependent manner. Worthy, we demonstrated that the GPER-mediated increase of SERPINB2 is engaged in the anti-migratory and anti-invasive effects elicited by E4 in TNBC cells. In accordance with these findings, a correlation between SERPINB2 levels and a good clinical outcome was found in ER-negative breast cancer patients.

CONCLUSIONS

Overall, our results provide new insights into the mechanisms through which E4 can halt migratory and invasive features of TNBC cells.

Pulmonary arterial hypertension: Sex matters

Pulmonary arterial hypertension (PAH) is a complex disease of multifactorial origin. While registries have demonstrated that women are more susceptible to the disease, females with PAH have superior right ventricle (RV) function and a better prognosis than their male counterparts, a phenomenon referred to as the 'estrogen paradox'. Numerous pre-clinical studies have investigated the involvement of sex hormones in PAH pathobiology, often with conflicting results. However, recent advances suggest that abnormal estrogen synthesis, metabolism and signalling underpin the sexual dimorphism of this disease. Other sex hormones, such as progesterone, testosterone and dehydroepiandrosterone may also play a role. Several non-hormonal factor including sex chromosomes and epigenetics have also been implicated. Though the underlying pathophysiological mechanisms are complex, several compounds that modulate sex hormones levels and signalling are under investigation in PAH patients. Further elucidation of the estrogen paradox will set the stage for the identification of additional therapeutic targets for this disease.

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.

Protective role of estrogen through G-protein coupled receptor 30 in a colitis mouse model

Estrogen and its receptors are involved in the pathogenesis of gastrointestinal diseases such as colitis. However, the role of the membrane estrogen receptor G-protein-coupled receptor 30 (GPR30) in colitis is poorly understood. We therefore investigated the effect of estrogen in dextran sulfate sodium (DSS)-induced colitis. Male C57BL/6 mice were administered 1.5% DSS for 5 days and treated with 17β-estradiol (E2), GPR30 agonist (G1), or GPR30 antagonist (G15) for 8 days. Inflammation grade was evaluated by disease activity index (DAI) and histomorphological score. Colon tissues were immunohistochemically analyzed and revealed high expression of membrane GPR30, histone 3 lysine 36 dimethylation, and lysine 79 trimethylation in normal mouse colon epithelial cells but significantly decreased expression in DSS-treated mice, whereas the expression was partially preserved after treatment with E2 or G1. Colon shortening and DAI were significantly lower in E2- and G1-treated mice compared to DSS-treated mice. Caudal type homeobox 2 (CDX2) expression and cell proliferation differed in normal colon epithelial cells but overlapped in those of DSS-treated mice. Administration of E2 and G1 reduced CDX2 expression and cell proliferation. Altered expression of claudin-2 and occludin were observed in the colonic epithelium of DSS-treated mice, and these changes were significantly lower in the colon of E2- and G1-treated mice. These results indicate that estrogen regulates histone modification, cell proliferation, and CDX2 expression through GPR30, which affects intestinal epithelial barrier function. We conclude that estrogen protects against intestinal epithelial damage through GPR30 by enhancing intestinal epithelial barrier function in DSS-induced colitis in mice.

The Role of the Tumor Microenvironment in Triple-Positive Breast Cancer Progression and Therapeutic Resistance

Breast cancer (BRCA) is a highly heterogeneous systemic disease. It is ranked first globally in the incidence of new cancer cases and has emerged as the primary cause of cancer-related death among females. Among the distinct subtypes of BRCA, triple-positive breast cancer (TPBC) has been associated with increased metastasis and invasiveness, exhibiting greater resistance to endocrine therapy involving trastuzumab. It is now understood that invasion, metastasis, and treatment resistance associated with BRCA progression are not exclusively due to breast tumor cells but are from the intricate interplay between BRCA and its tumor microenvironment (TME). Accordingly, understanding the pathogenesis and evolution of the TPBC microenvironment demands a comprehensive approach. Moreover, addressing BRCA treatment necessitates a holistic consideration of the TME, bearing significant implications for identifying novel targets for anticancer interventions. This review expounds on the relationship between critical cellular components and factors in the TPBC microenvironment and the inception, advancement, and therapeutic resistance of breast cancer to provide perspectives on the latest research on TPBC.

Divergent features of ERβ isoforms in triple negative breast cancer: progress and implications for further research

Estrogen receptor β (ERβ) was discovered more than 20 years ago. However, the extent and role of ERβ expression in breast cancer remain controversial, especially in the context of triple-negative breast cancer (TNBC). ERβ exists as multiple isoforms, and a series of studies has revealed an inconsistent role of ERβ isoforms in TNBC. Our recent results demonstrated contrasting functions of ERβ1 and ERβ2/β5 in TNBC. Additional research should be conducted to explore the functions of individual ERβ isoforms and develop targeted drugs according to the relevant mechanisms. Consequently, a systematic review of ERβ isoforms is necessary. In this review, we overview the structure of ERβ isoforms and detail what is known about the function of ERβ isoforms in normal mammary tissue and breast cancer. Moreover, this review highlights the divergent features of ERβ isoforms in TNBC. This review also provides insights into the implications of targeting ERβ isoforms for clinical treatment. In conclusion, this review provides a framework delineating the roles and mechanisms of different ERβ isoforms in TNBC and sheds light on future directions for basic and clinical research.

GPER: An Estrogen Receptor Key in Metastasis and Tumoral Microenvironments

Estrogens and their role in cancer are well-studied, and some cancer types are classified in terms of their response to them. In recent years, a G protein-coupled estrogen receptor (GPER) has been described with relevance in cancer. GPER is a pleiotropic receptor with tissue-specific activity; in normal tissues, its activation is related to correct development and homeostasis, while in cancer cells, it can be pro- or anti-tumorigenic. Also, GPER replaces estrogen responsiveness in estrogen receptor alpha (ERα)-lacking cancer cell lines. One of the most outstanding activities of GPER is its role in epithelial-mesenchymal transition (EMT), which is relevant for metastasis development. In addition, the presence of this receptor in tumor microenvironment cells contributes to the phenotypic plasticity required for the dissemination and maintenance of tumors. These characteristics suggest that GPER could be a promising therapeutic target for regulating cancer development. This review focuses on the role of GPER in EMT in tumorigenic and associated cells, highlighting its role in relation to the main hallmarks of cancer and possible therapeutic options.

The G protein-coupled oestrogen receptor GPER in health and disease: an update

Oestrogens and their receptors contribute broadly to physiology and diseases. In premenopausal women, endogenous oestrogens protect against cardiovascular, metabolic and neurological diseases and are involved in hormone-sensitive cancers such as breast cancer. Oestrogens and oestrogen mimetics mediate their effects via the cytosolic and nuclear receptors oestrogen receptor-α (ERα) and oestrogen receptor-β (ERβ) and membrane subpopulations as well as the 7-transmembrane G protein-coupled oestrogen receptor (GPER). GPER, which dates back more than 450 million years in evolution, mediates both rapid signalling and transcriptional regulation. Oestrogen mimetics (such as phytooestrogens and xenooestrogens including endocrine disruptors) and licensed drugs such as selective oestrogen receptor modulators (SERMs) and downregulators (SERDs) also modulate oestrogen receptor activity in both health and disease. Following up on our previous Review of 2011, we herein summarize the progress made in the field of GPER research over the past decade. We will review molecular, cellular and pharmacological aspects of GPER signalling and function, its contribution to physiology, health and disease, and the potential of GPER to serve as a therapeutic target and prognostic indicator of numerous diseases. We also discuss the first clinical trial evaluating a GPER-selective drug and the opportunity of repurposing licensed drugs for the targeting of GPER in clinical medicine.

Breast cancer progression and kynurenine pathway enzymes are induced by hexachlorobenzene exposure in a Her2-positive model

Breast cancer is one of the leading cancers among women worldwide. Given the evidence that pesticides play an important role in breast cancer, interest has grown in pesticide impact on disease progression. Hexachlorobenzene (HCB), an aryl hydrocarbon receptor (AhR) ligand, promotes triple-negative breast cancer cell migration and invasion. Estrogen receptor β (ERβ) inhibits cancer motility, while G protein-coupled ER (GPER) modulates the neoplastic transformation. Tryptophan is metabolized through the kynurenine pathway by indoleamine-2,3-dioxygenase (IDO) and tryptophan-2,3-dioxygenase (TDO), with kynurenine signaling activation often predicting worse prognosis in cancer. In this context, we examined the HCB (0.005; 0.05; 0.5 and 5 μM) effect on LM3 cells, a human epidermal growth factor receptor 2 (HER2)-positive breast cancer model. Results show that HCB increases IDO and TDO mRNA levels and promotes cell viability, proliferation and migration through the AhR pathway. Moreover, HCB boosts mammosphere formation, vascular endothelial growth factor and cyclooxygenase-2 expression and reduces IL-10 levels. For some parameters, U-shaped or inverted U-shaped dose-response curves are shown. HCB alters ER levels, reducing ERβ while increasing GPER. These results demonstrate that exposure to environmentally relevant concentrations of HCB up-regulates the kynurenine pathway and dysregulates ERβ and GPER levels, collaborating in HER2-positive breast cancer progression.

A Basic Review on Estrogen Receptor Signaling Pathways in Breast Cancer

Breast cancer is the most common cancer and the deadliest among women worldwide. Estrogen signaling is closely associated with hormone-dependent breast cancer (estrogen and progesterone receptor positive), which accounts for two-thirds of tumors. Hormone therapy using antiestrogens is the gold standard, but resistance to these treatments invariably occurs through various biological mechanisms, such as changes in estrogen receptor activity, mutations in the ESR1 gene, aberrant activation of the PI3K pathway or cell cycle dysregulations. All these factors have led to the development of new therapies, such as selective estrogen receptor degraders (SERDs), or combination therapies with cyclin-dependent kinases (CDK) 4/6 or PI3K inhibitors. Therefore, understanding the estrogen pathway is essential for the treatment and new drug development of hormone-dependent cancers. This mini-review summarizes current literature on the signalization, mechanisms of action and clinical implications of estrogen receptors in breast cancer.

Physalis alkekengi L. var. franchetii combined with hormone therapy for atopic dermatitis

Atopic dermatitis (AD) is a common, chronic, and recurring inflammatory skin disease. Physalis alkekengi L. var. franchetii (Mast) Makino (PAF), a traditional Chinese medicine, is primarily used for the clinical treatment of AD. In this study, a 2,4-dinitrochlorobenzene-induced AD BALB/c mouse model was established, and a comprehensive pharmacological method was used to determine the pharmacological effects and molecular mechanisms of PAF in the treatment of AD. The results indicated that both PAF gel (PAFG) and PAFG+MF (mometasone furoate) attenuated the severity of AD and reduced the infiltration of eosinophils and mast cells in the skin. Serum metabolomics showed that PAFG combined with MF administration exerted a synergistic effect by remodeling metabolic disorders in mice. In addition, PAFG also alleviated the side effects of thymic atrophy and growth inhibition induced by MF. Network pharmacology predicted that the active ingredients of PAF were flavonoids and exerted therapeutic effects through anti-inflammatory effects. Finally, immunohistochemical analysis confirmed that PAFG inhibited the inflammatory response through the ERβ/HIF-1α/VEGF signaling pathway. Our results revealed that PAF can be used as a natural-source drug with good development prospects for the clinical treatment of AD.

GPER-mediated stabilization of HIF-1α contributes to upregulated aerobic glycolysis in tamoxifen-resistant cells

Tamoxifen is a first-line therapeutic drug for oestrogen-receptor positive breast cancer; however, like other therapeutics, its clinical use is limited by acquired resistance. Tamoxifen-resistant cells have demonstrated enhanced aerobic glycolysis; however, the mechanisms underlying this upregulation remain unclear. Here, we demonstrated that G-protein coupled oestrogen receptor (GPER) was involved in the upregulation of aerobic glycolysis via induction of hypoxia-inducible factor-1α (HIF-1α) expression and transcriptional activity in tamoxifen-resistant cells. Additionally, GPER stabilized HIF-1α through inhibiting its hydroxylation and ubiquitin-mediated degradation, which were associated with upregulation of C-terminal hydrolase-L1 (UCH-L1), downregulation of prolyl hydroxylase 2 (PHD2) and von Hippel-Lindau tumour suppressor protein (pVHL), induction of HIF-1α/UCH-L1 interaction, and suppression of HIF-1α/PHD2-pVHL association. The GPER/HIF-1α axis was functionally responsible for regulating tamoxifen sensitivity both in vitro and in vivo. Moreover, there was a positive correlation between GPER and HIF-1α expression in clinical breast cancer tissues, and high levels of GPER combined with nuclear HIF-1α indicated poor overall survival. High levels of the GPER/HIF-1α axis were also correlated with shorter relapse-free survival in patients receiving tamoxifen. Hence, our findings support a critical role of GPER/HIF-1α axis in the regulation of aerobic glycolysis in tamoxifen-resistant cells, offering a potential therapeutic target for tamoxifen-resistant breast cancer.

Comparative G-Protein-Coupled Estrogen Receptor (GPER) Systems in Diabetic and Cancer Conditions: A Review

For many patients, diabetes Mellitus and Malignancy are frequently encountered comorbidities. Diabetes affects approximately 10.5% of the global population, while malignancy accounts for 29.4 million cases each year. These troubling statistics indicate that current treatment approaches for these diseases are insufficient. Alternative therapeutic strategies that consider unique signaling pathways in diabetic and malignancy patients could provide improved therapeutic outcomes. The G-protein-coupled estrogen receptor (GPER) is receiving attention for its role in disease pathogenesis and treatment outcomes. This review aims to critically examine GPER' s comparative role in diabetes mellitus and malignancy, identify research gaps that need to be filled, and highlight GPER's potential as a therapeutic target for diabetes and malignancy management. There is a scarcity of data on GPER expression patterns in diabetic models; however, for diabetes mellitus, altered expression of transport and signaling proteins has been linked to GPER signaling. In contrast, GPER expression in various malignancy types appears to be complex and debatable at the moment. Current data show inconclusive patterns of GPER expression in various malignancies, with some indicating upregulation and others demonstrating downregulation. Further research should be conducted to investigate GPER expression patterns and their relationship with signaling pathways in diabetes mellitus and various malignancies. We conclude that GPER has therapeutic potential for chronic diseases such as diabetes mellitus and malignancy.

An overview on Estrogen receptors signaling and its ligands in breast cancer

Estrogen governs the regulations of various pathological and physiological actions throughout the body in both males and females. Generally, 17β-estradiol an endogenous estrogen is responsible for different health problems in pre and postmenopausal women. The major activities of endogenous estrogen are executed by nuclear estrogen receptors (ERs) ERα and ERβ while non-genomic cytoplasmic pathways also govern cell growth and apoptosis. Estrogen accomplished a fundamental role in the formation and progression of breast cancer. In this review, we have hyphenated different studies regarding ERs and a thorough and detailed study of estrogen receptors is presented. This review highlights different aspects of estrogens ranging from receptor types, their isoforms, structures, signaling pathways of ERα, ERβ and GPER along with their crystal structures, pathological roles of ER, ER ligands, and therapeutic strategies to overcome the resistance.

Identification of molecular initiating events and key events leading to endocrine disrupting effects of PFOA: Integrated molecular dynamic, transcriptomic, and proteomic analyses

Perfluorooctanoic acid (PFOA) can rapidly activate signaling pathways independent of nuclear hormone receptors through membrane receptor regulation, which leads to endocrine disrupting effects. In the present work, the molecular initiating event (MIE) and the key events (KEs) which cause the endocrine disrupting effects of PFOA have been explored and determined based on molecular dynamics simulation (MD), fluorescence analysis, transcriptomics, and proteomics. MD modeling and fluorescence analysis proved that, on binding to the G protein-coupled estrogen receptor-1 (GPER), PFOA could induce a conformational change in the receptor, turning it into an active state. The results also indicated that the binding to GPER was the MIE that led to the adverse outcome (AO) of PFOA. In addition, the downstream signal transduction pathways of GPER, as regulated by PFOA, were further investigated through genomics and proteomics to identify the KEs leading to thr endocrine disrupting effects. Two pathways (Endocrine resistance, ERP and Estrogen signaling pathway, ESP) containing GPER were regulated by different concentration of PFOA and identified as the KEs. The knowledge of MIE, KEs, and AO of PFOA is necessary to understand the links between PFOA and the possible pathways that lead to its negative effects.

Dibutyl phthalate promotes angiogenesis in EA.hy926 cells through estrogen receptor-dependent activation of ERK1/2, PI3K-Akt, and NO signaling pathways

Dibutyl phthalate (DBP) is an endocrine disruptor that has been widely used in various products of human use. DBP exposure has been associated with reproductive and cardiovascular diseases and metabolic disorders. Although dysfunction of the vascular endothelium is responsible for many cardiovascular and metabolic diseases, little is known about the effects of DBP on human endothelium. In this study, we investigated the effect of three concentrations of DBP (10^-6, 10^-5, and 10^-4 M) on angiogenesis in human endothelial cell (EC) line EA.hy926 after acute exposure. Tube formation assay was used to investigate in vitro angiogenesis, whereas qRT-PCR was employed to measure mRNA expression. The effect of DBP on extracellular signal-regulated kinase 1/2 (ERK1/2), phosphatidylinositol 3-kinase (PI3K)-protein kinase B (Akt), and endothelial nitric oxide (NO) synthase (eNOS) activation was examined using Western blotting, whereas the Griess method was used to assess NO production. Results show that the 24-h-long exposure to 10^-4 M DBP increased endothelial tube formation, which was prevented by addition of U0126 (ERK1/2 inhibitor), wortmannin (PI3K-Akt inhibitor), and l-NAME (NOS inhibitor). Short exposure to 10^-4 M DBP (from 15 to 120 min) phosphorylated ERK1/2, Akt, and eNOS in different time points and increased NO production after 24 and 48 h of exposure. Application of nuclear estrogen receptor (ER) and G protein-coupled ER (GPER) inhibitors ICI 182,780 and G-15, respectively, abolished the DBP-mediated ERK1/2, Akt, and eNOS phosphorylation and increase in NO production. In this study, we report for the first time that DBP exerts a pro-angiogenic effect on human vascular ECs and describe the molecular mechanism involving ER- and GPER-dependent activation of ERK1/2, PI3K-Akt, and NO signaling pathways.

The AGEs/RAGE Transduction Signaling Prompts IL-8/CXCR1/2-Mediated Interaction between Cancer-Associated Fibroblasts (CAFs) and Breast Cancer Cells

Advanced glycation end products (AGEs) and the cognate receptor, named RAGE, are involved in metabolic disorders characterized by hyperglycemia, type 2 diabetes mellitus (T2DM) and obesity. Moreover, the AGEs/RAGE transduction pathway prompts a dysfunctional interaction between breast cancer cells and tumor stroma toward the acquisition of malignant features. However, the action of the AGEs/RAGE axis in the main players of the tumor microenvironment, named breast cancer-associated fibroblasts (CAFs), remains to be fully explored. In the present study, by chemokine array, we first assessed that interleukin-8 (IL-8) is the most up-regulated pro-inflammatory chemokine upon AGEs/RAGE activation in primary CAFs, obtained from breast tumors. Thereafter, we ascertained that the AGEs/RAGE signaling promotes a network cascade in CAFs, leading to the c-Fos-dependent regulation of IL-8. Next, using a conditioned medium from AGEs-exposed CAFs, we determined that IL-8/CXCR1/2 paracrine activation induces the acquisition of migratory and invasive features in MDA-MB-231 breast cancer cells. Altogether, our data provide new insights on the involvement of IL-8 in the AGEs/RAGE transduction pathway among the intricate connections linking breast cancer cells to the surrounding stroma. Hence, our findings may pave the way for further investigations to define the role of IL-8 as useful target for the better management of breast cancer patients exhibiting metabolic disorders.

Modulatory Effects of Estradiol and Its Mixtures with Ligands of GPER and PPAR on MAPK and PI3K/Akt Signaling Pathways and Tumorigenic Factors in Mouse Testis Explants and Mouse Tumor Leydig Cells

The present study was designed to evaluate how estradiol alone or in combination with G protein-coupled estrogen receptor (GPER) agonists and GPER and peroxisome proliferator-activated receptor (PPAR) antagonists alter the expression of tumor growth factor β (TGF-β), cyclooxygenase-2 (COX-2), hypoxia inducible factor 1-alpha (HIF-1α), and vascular endothelial growth factor (VEGF) in mouse testis explants and MA-10 mouse tumor Leydig cells. In order to define the hormone-associated signaling pathway, the expression of MAPK and PI3K/Akt was also examined. Tissue explants and cells were treated with estradiol as well as GPER agonist (ICI 182,780), GPER antagonist (G-15), PPARα antagonist (GW6471), and PPARγ antagonist (T00709072) in various combinations. First, we showed that in testis explants GPER and PPARα expressions were activated by the GPER agonist and estradiol (either alone or in mixtures), whereas PPARγ expression was activated only by GPER agonist. Second, increased TGF-β expression and decreased COX-2 expression were found in all experimental groups of testicular explants and MA-10 cells, except for up-regulated COX-2 expression in estradiol-treated cells, compared to respective controls. Third, estradiol treatment led to elevated expression of HIF-1α and VEGF, while their lower levels versus control were noted in the remaining groups of explants. Finally, we demonstrated the up-regulation of MAPK and PI3Kp85/Akt expressions in estradiol-treated groups of both ex vivo and in vitro models, whereas estradiol in mixtures with compounds of agonistic or antagonistic properties either up-regulated or down-regulated signaling kinase expression levels. Our results suggest that a balanced estrogen level and its action together with proper GPER and PPAR signaling play a key role in the maintenance of testis homeostasis. Moreover, changes in TGF-β and COX-2 expressions (that disrupted estrogen pathway) as well as disturbed GPER-PPAR signaling observed after estradiol treatment may be involved in testicular tumorigenesis.

Estrogen and G protein-coupled estrogen receptor accelerate the progression of benign prostatic hyperplasia by inducing prostatic fibrosis

Benign prostatic hyperplasia (BPH) is the most common and progressive urological disease in elderly men worldwide. Epidemiological studies have suggested that the speed of disease progression varies among individuals, while the pathophysiological mechanisms of accelerated clinical progression in some BPH patients remain to be elucidated. In this study, we defined patients with BPH as belonging to the accelerated progressive group (transurethral resection of the prostate [TURP] surgery at ≤50 years old), normal-speed progressive group (TURP surgery at ≥70 years old), or non-progressive group (age ≤50 years old without BPH-related surgery). We enrolled prostate specimens from the three groups of patients and compared these tissues to determine the histopathological characteristics and molecular mechanisms underlying BPH patients with accelerated progression. We found that the main histopathological characteristics of accelerated progressive BPH tissues were increased stromal components and prostatic fibrosis, which were accompanied by higher myofibroblast accumulation and collagen deposition. Mechanism dissection demonstrated that these accelerated progressive BPH tissues have higher expression of the CYP19 and G protein-coupled estrogen receptor (GPER) with higher estrogen biosynthesis. Estrogen functions via GPER/Gαi signaling to modulate the EGFR/ERK and HIF-1α/TGF-β1 signaling to increase prostatic stromal cell proliferation and prostatic stromal fibrosis. The increased stromal components and prostatic fibrosis may accelerate the clinical progression of BPH. Targeting this newly identified CYP19/estrogen/GPER/Gαi signaling axis may facilitate the development of novel personalized therapeutics to better suppress the progression of BPH.

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.

Multifaceted Interplay between Hormones, Growth Factors and Hypoxia in the Tumor Microenvironment

Hormones and growth factors (GFs) are signaling molecules implicated in the regulation of a variety of cellular processes. They play important roles in both healthy and tumor cells, where they function by binding to specific receptors on target cells and activating downstream signaling cascades. The stages of tumor progression are influenced by hormones and GF signaling. Hypoxia, a hallmark of cancer progression, contributes to tumor plasticity and heterogeneity. Most solid tumors contain a hypoxic core due to rapid cellular proliferation that outgrows the blood supply. In these circumstances, hypoxia-inducible factors (HIFs) play a central role in the adaptation of tumor cells to their new environment, dramatically reshaping their transcriptional profile. HIF signaling is modulated by a variety of factors including hormones and GFs, which activate signaling pathways that enhance tumor growth and metastatic potential and impair responses to therapy. In this review, we summarize the role of hormones and GFs during cancer onset and progression with a particular focus on hypoxia and the interplay with HIF proteins. We also discuss how hypoxia influences the efficacy of cancer immunotherapy, considering that a hypoxic environment may act as a determinant of the immune-excluded phenotype and a major hindrance to the success of adoptive cell therapies.

Sex-Based Differences in the Tumor Microenvironment

Cancers are heterogeneous multifactorial diseases consisting of a major public health issue worldwide. Sex disparities are evidenced in cancer incidence, mortality, expression of prognosis factor, response to treatment, and survival. For both sexes, an interplay of intrinsic and environmental factors influences cancer cells and tumor microenvironment (TME) components. The TME cumulates both supportive and communicative functions, contributing to cancer development, progression, and metastasis dissemination. The frontline topics of this chapter are focused on the contribution of sex, via steroid hormones, such as estrogens and androgens, on the following components of the TME: cancer-associated fibroblasts (CAFs), extracellular matrix (ECM), blood and lymphatic endothelial cells, and immunity/inflammatory system.

A review of the functions of G protein-coupled estrogen receptor 1 in vascular and neurological aging

Aging-related diseases, especially vascular and neurological disorders cause huge economic burden. How to delay vascular and neurological aging is one of the insurmountable questions. G protein-coupled estrogen receptor 1 (GPER) has been extensively investigated in recent years due to its multiple biological responses. In this review, the function of GPER in aging-related diseases represented by vascular diseases, and neurological disorders were discussed. Apart from that, activation of GPER was also found to renovate the aging brain characterized by memory decline, but in a manner different from another two nuclear estrogen receptors estrogen receptor (ER)α and ERβ. This salutary effect would be better clarified from the aspects of synaptic inputs and transmission. Furthermore, we carefully described molecular mechanisms underpinning GPER-mediated effects. This review would update our understanding of GPER in the aging process. Targeting GPER may represent a promising strategy in the aging-related disorders.

Targeting obesity-related dysfunction in hormonally driven cancers

Obesity is a risk factor for at least 13 different types of cancer, many of which are hormonally driven, and is associated with increased cancer incidence and morbidity. Adult obesity rates are steadily increasing and a subsequent increase in cancer burden is anticipated. Obesity-related dysfunction can contribute to cancer pathogenesis and treatment resistance through various mechanisms, including those mediated by insulin, leptin, adipokine, and aromatase signalling pathways, particularly in women. Furthermore, adiposity-related changes can influence tumour vascularity and inflammation in the tumour microenvironment, which can support tumour development and growth. Trials investigating non-pharmacological approaches to target the mechanisms driving obesity-mediated cancer pathogenesis are emerging and are necessary to better appreciate the interplay between malignancy, adiposity, diet and exercise. Diet, exercise and bariatric surgery are potential strategies to reverse the cancer-promoting effects of obesity; trials of these interventions should be conducted in a scientifically rigorous manner with dose escalation and appropriate selection of tumour phenotypes and have cancer-related clinical and mechanistic endpoints. We are only beginning to understand the mechanisms by which obesity effects cell signalling and systemic factors that contribute to oncogenesis. As the rates of obesity and cancer increase, we must promote the development of non-pharmacological lifestyle trials for the treatment and prevention of malignancy.

Characterization of structural variation in Tibetans reveals new evidence of high-altitude adaptation and introgression

BACKGROUND

Structural variation (SV) acts as an essential mutational force shaping the evolution and function of the human genome. However, few studies have examined the role of SVs in high-altitude adaptation and little is known of adaptive introgressed SVs in Tibetans so far.

RESULTS

Here, we generate a comprehensive catalog of SVs in a Chinese Tibetan (n = 15) and Han (n = 10) population using nanopore sequencing technology. Among a total of 38,216 unique SVs in the catalog, 27% are sequence-resolved for the first time. We systematically assess the distribution of these SVs across repeat sequences and functional genomic regions. Through genotyping in additional 276 genomes, we identify 69 Tibetan-Han stratified SVs and 80 candidate adaptive genes. We also discover a few adaptive introgressed SV candidates and provide evidence for a deletion of 335 base pairs at 1p36.32.

CONCLUSIONS

Overall, our results highlight the important role of SVs in the evolutionary processes of Tibetans' adaptation to the Qinghai-Tibet Plateau and provide a valuable resource for future high-altitude adaptation studies.

S100A4 Is Involved in Stimulatory Effects Elicited by the FGF2/FGFR1 Signaling Pathway in Triple-Negative Breast Cancer (TNBC) Cells

Triple-negative breast cancer (TNBC) is an aggressive breast tumor subtype characterized by poor clinical outcome. In recent years, numerous advancements have been made to better understand the biological landscape of TNBC, though appropriate targets still remain to be determined. In the present study, we have determined that the expression levels of FGF2 and S100A4 are higher in TNBC with respect to non-TNBC patients when analyzing “The Invasive Breast Cancer Cohort of The Cancer Genome Atlas” (TCGA) dataset. In addition, we have found that the gene expression of FGF2 is positively correlated with S100A4 in TNBC samples. Performing quantitative PCR, Western blot, CRISPR/Cas9 genome editing, promoter studies, immunofluorescence analysis, subcellular fractionation studies, and ChIP assays, we have also demonstrated that FGF2 induces in TNBC cells the upregulation and secretion of S100A4 via FGFR1, along with the ERK1/2–AKT–c-Rel transduction signaling. Using conditioned medium from TNBC cells stimulated with FGF2, we have also ascertained that the paracrine activation of the S100A4/RAGE pathway triggers angiogenic effects in vascular endothelial cells (HUVECs) and promotes the migration of cancer-associated fibroblasts (CAFs). Collectively, our data provide novel insights into the action of the FGF2/FGFR1 axis through S100A4 toward stimulatory effects elicited in TNBC cells.

The flavonoid, kaempferol-3-O-apiofuranosyl-7-O-rhamnopyranosyl, as a potential therapeutic agent for breast cancer with a promoting effect on ovarian function

It is widely known that breast cancer cells eventually develop resistance to hormonal drugs and chemotherapies, which often compromise fertility. This study aimed to investigate the effect of the flavonoid, kaempferol-3-O-apiofuranosyl-7-O-rhamnopyranosyl (KARP), on 1) the viability of MCF-7 breast cancer cells and 2) ovarian function in rats. A dose-dependent decrease in MCF-7 cell survival was observed, and the IC50 value was found to be 48 μg/ml. Cells in the control group or those exposed to increasing concentrations of KARP experienced a similar generation of reactive oxygen species and induction of apoptosis. For the rats, estradiol levels correlated negatively to KARP dosages, although a recovery was obtained at administration of 30 mg/kg per day. Noteworthily, when compared against the control, this dosage led to significant increases in mRNA levels for CYP19, CYP17a, CCND2, GDF9, and INSL3 among the treatment groups, and ER1 and ER2 mRNA levels decreased in a dose-dependent manner. KARP shows great promise as an ideal therapy for breast cancer patients since it induced apoptosis and autophagy in cancerous cells without harming fertility in our animal model. Future investigations on humans are necessary to substantiate these findings and determine its efficacy as a general line of treatment.

G Protein-Coupled Estrogen Receptor in Cancer and Stromal Cells: Functions and Novel Therapeutic Perspectives

Estrogen is involved in numerous physiological and pathophysiological systems. Its role in driving estrogen receptor-expressing breast cancers is well established, but it also has important roles in a number of other cancers, acting both on tumor cells directly as well as in the function of multiple cells of the tumor microenvironment, including fibroblasts, immune cells, and adipocytes, which can greatly impact carcinogenesis. One of its receptors, the G protein-coupled estrogen receptor (GPER), has gained much interest over the last decade in both health and disease. Increasing evidence shows that GPER contributes to clinically observed endocrine therapy resistance in breast cancer while also playing a complex role in a number of other cancers. Recent discoveries regarding the targeting of GPER in combination with immune checkpoint inhibition, particularly in melanoma, have led to the initiation of the first Phase I clinical trial for the GPER-selective agonist G-1. Furthermore, its functions in metabolism and corresponding pathophysiological states, such as obesity and diabetes, are becoming more evident and suggest additional therapeutic value in targeting GPER for both cancer and other diseases. Here, we highlight the roles of GPER in several cancers, as well as in metabolism and immune regulation, and discuss the therapeutic value of targeting this estrogen receptor as a potential treatment for cancer as well as contributing metabolic and inflammatory diseases and conditions.

Sexual hormones and diabetes: The impact of estradiol in pancreatic β cell

Diabetes is one of the most prevalent metabolic diseases and its incidence is increasing throughout the world. Data from World Health Organization (WHO) point-out that diabetes is a major cause of blindness, kidney failure, heart attacks, stroke and lower limb amputation and estimated 1.6 million deaths were directly caused by it in 2016. Population studies show that the incidence of this disease increases in women after menopause, when the production of estrogen is decreasing in them. Knowing the impact that estrogenic signaling has on insulin-secreting β cells is key to prevention and design of new therapeutic targets. This chapter explores the role of estrogen and their receptors in the regulation of insulin secretion and biosynthesis, proliferation, regeneration and survival in pancreatic β cells. In addition, delves into the genetic animal models developed and its application for the specific study of the different estrogen signaling pathways. Finally, discusses the impact of menopause and hormone replacement therapy on pancreatic β cell function.

Activation of G protein-coupled estrogen receptor 1 ameliorates proximal tubular injury and proteinuria in Dahl salt-sensitive female rats

Recent evidence indicates a crucial role for G protein-coupled estrogen receptor 1 (GPER1) in the maintenance of cardiovascular and kidney health in females. The current study tested whether GPER1 activation ameliorates hypertension and kidney damage in female Dahl salt-sensitive (SS) rats fed a high-salt (HS) diet. Adult female rats were implanted with telemetry transmitters for monitoring blood pressure and osmotic minipumps releasing G1 (selective GPER1 agonist, 400 μg/kg/day ip) or vehicle. Two weeks after pump implantation, rats were shifted from a normal-salt (NS) diet (0.4% NaCl) to a matched HS diet (4.0% NaCl) for 2 wk. Twenty-four hour urine samples were collected during both diet periods and urinary markers of kidney injury were assessed. Histological assessment of kidney injury was conducted after the 2-wk HS diet period. Compared with values during the NS diet, 24-h mean arterial pressure markedly increased in response to HS, reaching similar values in vehicle-treated and G1-treated rats. HS also significantly increased urinary excretion of protein, albumin, nephrin (podocyte damage marker), and KIM-1 (proximal tubule injury marker) in vehicle-treated rats. Importantly, G1 treatment prevented the HS-induced proteinuria, albuminuria, and increase in KIM-1 excretion but not nephrinuria. Histological analysis revealed that HS-induced glomerular damage did not differ between groups. However, G1 treatment preserved proximal tubule brush-border integrity in HS-fed rats. Collectively, our data suggest that GPER1 activation protects against HS-induced proteinuria and albuminuria in female Dahl SS rats by preserving proximal tubule brush-border integrity in a blood pressure-independent manner.

Deciphering the Role of Autophagy in Treatment of Resistance Mechanisms in Glioblastoma

Autophagy is a process essential for cellular energy consumption, survival, and defense mechanisms. The role of autophagy in several types of human cancers has been explicitly explained; however, the underlying molecular mechanism of autophagy in glioblastoma remains ambiguous. Autophagy is thought to be a “double-edged sword”, and its effect on tumorigenesis varies with cell type. On the other hand, autophagy may play a significant role in the resistance mechanisms against various therapies. Therefore, it is of the utmost importance to gain insight into the molecular mechanisms deriving the autophagy-mediated therapeutic resistance and designing improved treatment strategies for glioblastoma. In this review, we discuss autophagy mechanisms, specifically its pro-survival and growth-suppressing mechanisms in glioblastomas. In addition, we try to shed some light on the autophagy-mediated activation of the cellular mechanisms supporting radioresistance and chemoresistance in glioblastoma. This review also highlights autophagy’s involvement in glioma stem cell behavior, underlining its role as a potential molecular target for therapeutic interventions.

Modifications on the Tetrahydroquinoline Scaffold Targeting a Phenylalanine Cluster on GPER as Antiproliferative Compounds against Renal, Liver and Pancreatic Cancer Cells

The implementation of chemo- and bioinformatics tools is a crucial step in the design of structure-based drugs, enabling the identification of more specific and effective molecules against cancer without side effects. In this study, three new compounds were designed and synthesized with suitable absorption, distribution, metabolism, excretion and toxicity (ADME-tox) properties and high affinity for the G protein-coupled estrogen receptor (GPER) binding site by in silico methods, which correlated with the growth inhibitory activity tested in a cluster of cancer cell lines. Docking and molecular dynamics (MD) simulations accompanied by a molecular mechanics/generalized Born surface area (MMGBSA) approach yielded the binding modes and energetic features of the proposed compounds on GPER. These in silico studies showed that the compounds reached the GPER binding site, establishing interactions with a phenylalanine cluster (F206, F208 and F278) required for GPER molecular recognition of its agonist and antagonist ligands. Finally, a 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bromide (MTT) assay showed growth inhibitory activity of compounds 4, 5 and 7 in three different cancer cell lines-MIA Paca-2, RCC4-VA and Hep G2-at micromolar concentrations. These new molecules with specific chemical modifications of the GPER pharmacophore open up the possibility of generating new compounds capable of reaching the GPER binding site with potential growth inhibitory activities against nonconventional GPER cell models.

Microenvironmental Determinants of Breast Cancer Metastasis: Focus on the Crucial Interplay Between Estrogen and Insulin/Insulin-Like Growth Factor Signaling

The development and progression of the great majority of breast cancers (BCs) are mainly dependent on the biological action elicited by estrogens through the classical estrogen receptor (ER), as well as the alternate receptor named G-protein–coupled estrogen receptor (GPER). In addition to estrogens, other hormones and growth factors, including the insulin and insulin-like growth factor system (IIGFs), play a role in BC. IIGFs cooperates with estrogen signaling to generate a multilevel cross-communication that ultimately facilitates the transition toward aggressive and life-threatening BC phenotypes. In this regard, the majority of BC deaths are correlated with the formation of metastatic lesions at distant sites. A thorough scrutiny of the biological and biochemical events orchestrating metastasis formation and dissemination has shown that virtually all cell types within the tumor microenvironment work closely with BC cells to seed cancerous units at distant sites. By establishing an intricate scheme of paracrine interactions that lead to the expression of genes involved in metastasis initiation, progression, and virulence, the cross-talk between BC cells and the surrounding microenvironmental components does dictate tumor fate and patients’ prognosis. Following (i) a description of the main microenvironmental events prompting BC metastases and (ii) a concise overview of estrogen and the IIGFs signaling and their major regulatory functions in BC, here we provide a comprehensive analysis of the most recent findings on the role of these transduction pathways toward metastatic dissemination. In particular, we focused our attention on the main microenvironmental targets of the estrogen-IIGFs interplay, and we recapitulated relevant molecular nodes that orientate shared biological responses fostering the metastatic program. On the basis of available studies, we propose that a functional cross-talk between estrogens and IIGFs, by affecting the BC microenvironment, may contribute to the metastatic process and may be regarded as a novel target for combination therapies aimed at preventing the metastatic evolution.

Capilliposide B blocks VEGF-induced angiogenesis in vitro in primary human retinal microvascular endothelial cells

Abnormal angiogenesis is associated with intraocular diseases such as proliferative diabetic retinopathy and neovascular age-related macular degeneration, and current therapies for these eye diseases are not satisfactory. The purpose of this study was to determine whether capilliposide B (CPS-B), a novel oleanane triterpenoid saponin derived from Lysimachia capillipes Hemsl, can inhibit vascular endothelial growth factor (VEGF)-induced angiogenesis signaling events and cellular responses in primary human retinal microvascular endothelial cells (HRECs). Our study revealed that the capilliposide B IC₅₀ for HRECs was 8.5 μM at 72 h and that 1 μM capilliposide B specifically inhibited VEGF-induced activation of VEGFR2 and its downstream signaling enzymes Akt and Erk. In addition, we discovered that this chemical effectively blocked VEGF-stimulated proliferation, migration and tube formation of the HRECs, suggesting that capilliposide B is a promising prophylactic for angiogenesis-associated diseases such as proliferative diabetic retinopathy.

Therapeutic Perspectives on the Modulation of G-Protein Coupled Estrogen Receptor, GPER, Function

Estrogens exert their physiological and pathophysiological effects via cellular receptors, named ERα, ERβ, and G-protein coupled estrogen receptor (GPER). Estrogen-regulated physiology is tightly controlled by factors that regulate estrogen bioavailability and receptor sensitivity, while disruption of these control mechanisms can result in loss of reproductive function, cancer, cardiovascular and neurodegenerative disease, obesity, insulin resistance, endometriosis, and systemic lupus erythematosus. Restoration of estrogen physiology by modulating estrogen bioavailability or receptor activity is an effective approach for treating these pathological conditions. Therapeutic interventions that block estrogen action are employed effectively for the treatment of breast and prostate cancer as well as for precocious puberty and anovulatory infertility. Theoretically, treatments that block estrogen biosynthesis should prevent estrogen action at ERs and GPER, although drug resistance and ligand-independent receptor activation may still occur. In addition, blockade of estrogen biosynthesis does not prevent activation of estrogen receptors by naturally occurring or man-made exogenous estrogens. A more complicated scenario is provided by anti-estrogen drugs that antagonize ERs since these drugs function as GPER agonists. Based upon its association with metabolic dysregulation and advanced cancer, GPER represents a therapeutic target with promise for the treatment of several critical health concerns facing Western society. Selective ligands that specifically target GPER have been developed and may soon serve as pharmacological agents for treating human disease. Here, we review current forms of estrogen therapy and the implications that GPER holds for these therapies. We also discuss existing GPER targeted drugs, additional approaches towards developing GPER-targeted therapies and how these therapies may complement existing modalities of estrogen-targeted therapy.

An Enriched Environment Enhances Angiogenesis Surrounding the Cingulum in Ischaemic Stroke Rats

An enriched environment (EE) has been demonstrated to improve functional recovery in animal models of ischaemic stroke through enhancing vascular endothelial growth factor- (VEGF-) mediated neuroprotection accompanied by angiogenesis in the ischaemic hemisphere. Whether EEs also promote VEGF-mediated neuroprotection and angiogenesis in the contralateral hemisphere remains unclear. Here, we explored the effect of EEs on VEGF expression and angiogenesis within the contralateral cerebral cortex in a rat middle cerebral artery occlusion/reperfusion (MCAO/r) model. We assessed the expression levels of platelet endothelial cell adhesion molecule-1 (CD31), VEGF, and endothelial nitric oxide synthase (eNOS) in the whole contralateral cerebral cortex using Western blotting assay but did not find an increase in the expression of CD31, VEGF, or eNOS in MCAO/r rats housed in EEs, which suggested that EEs did not enhance the overall expression of VEGF and eNOS or angiogenesis in the entire contralateral cortex. We further analysed the local effect of EEs by immunohistochemistry and found that in and around the bilateral cingulum in MCAO/r rats housed in EEs, haematopoietic progenitor cell antigen- (CD34-) positive endothelial progenitor cells were significantly increased compared with those of rats housed in standard cages (SCs). Further experiments showed that EEs increased neuronal VEGF expression surrounding the cingulum in MCAO/r rats and robustly upregulated eNOS expression. These results revealed that EEs enhanced angiogenesis, VEGF expression, and activation of the VEGF-eNOS pathway in and/or around the cingulum in MCAO/r rats, which were involved in the functional recovery of MCAO/r rats.

The value of red blood cell distribution width, neutrophil-to-lymphocyte ratio, and hemoglobin-to-red blood cell distribution width ratio in the progression of non-small cell lung cancer

Background

Lung cancer is the leading cause of cancer-related deaths worldwide, with non-small cell lung cancer (NSCLC) accounting for 85% of all lung cancer cases. Inflammation has been proven to be one of the characteristics of malignant tumors. Chronic inflammatory response mediated by cytokines in the tumor microenvironment is an important factor in tumorigenesis. The purpose of this study was to observe and evaluate the value of red blood cell distribution width (RDW), neutrophil-to-lymphocyte ratio (NLR), and hemoglobin-to-red blood cell distribution width ratio (HRR) in the progression of NSCLC.

Methods

A total of 245 patients with NSCLC, 97 patients with benign pulmonary nodules, and 94 healthy volunteers were included in this study. Factors, such as age, gender, smoking history, histological type, lymph node metastasis, distant metastasis, TNM stage, and differentiation degree were statistically analyzed. The correlation of RDW, NLR, and HRR of patients with NSCLC with other clinical experimental parameters were also analyzed. Then, the diagnostic value of RDW, NLR, and HRR in the progression of NSCLC was evaluated.

Results

RDW, NLR, and HRR could be used to distinguish patients with NSCLC from healthy controls (p < 0.05). In addition, only the RDW in the NSCLC group with III-IV stage was significantly different from that in the benign pulmonary nodules group (p = 0.033), while NLR and HRR could significantly distinguish patients with NSCLC and benign pulmonary nodules (p < 0.001). RDW and NLR were positively correlated with NSCLC stage, whereas HRR was negatively correlated with NSCLC stage. RDW, NLR, and HRR were also significantly associated with the differentiation degree of NSCLC (p < 0.05). The ROC curve analysis showed that the combination of RDW with NLR, HRR, and CEA could show significantly higher diagnostic value than any one marker alone (AUC = 0.925, 95% CI: 0.897–0.954, and sensitivity and specificity of 79.60% and 93.60%, respectively).

Conclusion

RDW, NLR, and HRR can be utilized as simple and effective biomarkers for the diagnosis and evaluation of NSCLC progression.

The IL1β-IL1R signaling is involved in the stimulatory effects triggered by hypoxia in breast cancer cells and cancer-associated fibroblasts (CAFs)

Background

Hypoxia plays a relevant role in tumor-related inflammation toward the metastatic spread and cancer aggressiveness. The pro-inflammatory cytokine interleukin-1β (IL-β) and its cognate receptor IL1R1 contribute to the initiation and progression of breast cancer determining pro-tumorigenic inflammatory responses. The transcriptional target of the hypoxia inducible factor-1α (HIF-1α) namely the G protein estrogen receptor (GPER) mediates a feedforward loop coupling IL-1β induction by breast cancer-associated fibroblasts (CAFs) to IL1R1 expression by breast cancer cells toward the regulation of target genes and relevant biological responses.

Methods

In order to ascertain the correlation of IL-β with HIF-1α and further hypoxia-related genes in triple-negative breast cancer (TNBC) patients, a bioinformatics analysis was performed using the information provided by The Invasive Breast Cancer Cohort of The Cancer Genome Atlas (TCGA) project and Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) datasets. Gene expression correlation, statistical analysis and gene set enrichment analysis (GSEA) were carried out with R studio packages. Pathway enrichment analysis was evaluated with Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway. TNBC cells and primary CAFs were used as model system. The molecular mechanisms implicated in the regulation of IL-1β by hypoxia toward a metastatic gene expression profile and invasive properties were assessed performing gene and protein expression studies, PCR arrays, gene silencing and immunofluorescence analysis, co-immunoprecipitation and ChiP assays, ELISA, cell spreading, invasion and spheroid formation.

Results

We first determined that IL-1β expression correlates with the levels of HIF-1α as well as with a hypoxia-related gene signature in TNBC patients. Next, we demonstrated that hypoxia triggers a functional liaison among HIF-1α, GPER and the IL-1β/IL1R1 signaling toward a metastatic gene signature and a feed-forward loop of IL-1β that leads to proliferative and invasive responses in TNBC cells. Furthermore, we found that the IL-1β released in the conditioned medium of TNBC cells exposed to hypoxic conditions promotes an invasive phenotype of CAFs.

Conclusions

Our data shed new light on the role of hypoxia in the activation of the IL-1β/IL1R1 signaling, which in turn triggers aggressive features in both TNBC cells and CAFs. Hence, our findings provide novel evidence regarding the mechanisms through which the hypoxic tumor microenvironment may contribute to breast cancer progression and suggest further targets useful in more comprehensive therapeutic strategies.

Computational Approaches for the Discovery of GPER Targeting Compounds

Estrogens exert a panel of biological activities mainly through the estrogen receptors α and β, which belong to the nuclear receptor superfamily. Diverse studies have shown that the G protein-coupled estrogen receptor 1 (GPER, previously known as GPR30) also mediates the multifaceted effects of estrogens in numerous pathophysiological events, including neurodegenerative, immune, metabolic, and cardiovascular disorders and the progression of different types of cancer. In particular, GPER is implicated in hormone-sensitive tumors, albeit diverse issues remain to be deeply investigated. As such, this receptor may represent an appealing target for therapeutics in different diseases. The yet unavailable complete GPER crystallographic structure, and its relatively low sequence similarity with the other members of the G protein-coupled receptor (GPCR) family, hamper the possibility to discover compounds able to modulate GPER activity. Consequently, a reliable molecular model of this receptor is required for the design of suitable ligands. To date, convergent approaches involving structure-based drug design and virtual ligand screening have led to the identification of several GPER selective ligands, thus providing important information regarding its mode of action and function. In this survey, we summarize results obtained through computer-aided techniques devoted to the assessment of GPER ligands toward their usefulness in innovative treatments of different diseases.

Autophagy as a Potential Therapy for Malignant Glioma

Glioma is the most frequent and aggressive type of brain neoplasm, being anaplastic astrocytoma (AA) and glioblastoma multiforme (GBM), its most malignant forms. The survival rate in patients with these neoplasms is 15 months after diagnosis, despite a diversity of treatments, including surgery, radiation, chemotherapy, and immunotherapy. The resistance of GBM to various therapies is due to a highly mutated genome; these genetic changes induce a de-regulation of several signaling pathways and result in higher cell proliferation rates, angiogenesis, invasion, and a marked resistance to apoptosis; this latter trait is a hallmark of highly invasive tumor cells, such as glioma cells. Due to a defective apoptosis in gliomas, induced autophagic death can be an alternative to remove tumor cells. Paradoxically, however, autophagy in cancer can promote either a cell death or survival. Modulating the autophagic pathway as a death mechanism for cancer cells has prompted the use of both inhibitors and autophagy inducers. The autophagic process, either as a cancer suppressing or inducing mechanism in high-grade gliomas is discussed in this review, along with therapeutic approaches to inhibit or induce autophagy in pre-clinical and clinical studies, aiming to increase the efficiency of conventional treatments to remove glioma neoplastic cells.

Oestrogen receptors and hypoxia inducible factor 1 alpha expression in abdominal wall endometriosis

RESEARCH QUESTION

What are the protein levels and localization of oestrogen receptors (including ERa, ERb and G protein-coupled oestrogen receptor [GPER]) and hypoxia-inducible factor-1alpha (HIF-1a) in normal control endometrium (COEM) and ectopic endometrium from abdominal wall endometriosis (AWE).

DESIGN

AWE (n = 20) were obtained during surgery; COEM (n = 40) were collected by curettage. All tissues were obtained during the proliferative or secretory phase. Formalin-fixed paraffin-embedded tissues were used for immunohistochemical study for oestrogen receptors and HIF-1a proteins.

RESULT(S)

The expression of oestrogen receptors and HIF-1a in AWE differed from that in the corresponding menstrual cycle phase of COEM. Compared with COEM, ERa and HIF-1a were decreased whereas ERb and GPER were increased in AWE. The greatest difference was in GPER, with increased protein expression in both the cytoplasm and nucleus of endometrial epithelial and stromal cells, as well as a distinct change in localization from cytoplasmic expression to nuclear and cytoplasmic expression, compared with COEM.

CONCLUSIONS

Our data suggest that the expression changes of oestrogen receptors and HIF-1a, especially GPER, are associated with AWE, which may provide new clues to understanding the cause of endometriosis.

Cancer associated fibroblasts: role in breast cancer and potential as therapeutic targets

Introduction: Cancer associated fibroblasts (CAFs) are the largest population of stromal cells in breast tumors. Emerging evidence has suggested that CAFs are important players not only in fostering tumor growth and spread but also in altering the tumor response to therapeutic agents. On the basis of these observations, huge efforts have been made to exploit CAFs as potential targets for breast cancer therapy.Areas covered: The current understanding of the hallmarks and biology of CAFs, their multilayered interplay with various cell populations of breast tumor microenvironment toward cancer initiation, progression, metastasis and resistance to anticancer therapies are discussed. In addition, a comprehensive overview of the CAFs-based molecular druggable targets in breast tumors is provided. The most relevant literature, in particular the studies retrieved in Medline in the last 10 years, served for this purpose.Expert opinion: The interest on CAFs as a target to fight breast cancer has becoming a hot topic for drug discovery. Indeed, several CAFs-targeted approaches are emerging as appealing therapeutic strategies in breast cancer. At pre-clinical level, this research field is speedily advancing toward the assessment of successful tactics targeting CAFs in breast cancer. Therefore, anti-CAFs therapies may display an intriguing potential to be exploited in clinical studies.

GPER Overexpression in Cervical Cancer Versus Premalignant Lesions: Its Activation Induces Different Forms of Cell Death

BACKGROUND

The effect of estrogen has been traditionally studied through the modulation of its alpha and beta nuclear receptors; however, the G Protein-Coupled Estrogen Receptor (GPER) has been recently involved in the pathology of numerous tumors. Although the study of GPER in cervical cancer has begun, its contribution still remains to be completely evaluated.

OBJECTIVE

The purpose of this work was to determine the expression of this receptor in different degrees of cervical lesions and whether the stimulation with its specific agonist (G-1) modulated mechanisms of cell survival or cell death in cervical cancer cells.

METHODS

Sections of 44 formalin-fixed paraffin-embedded blocks from patients were analyzed by automated immunohistochemistry. After the stimulation with G-1, proliferation was evaluated by the xCELLigence technology, the integrity of the mitochondrial membrane permeability by MitoCaptureTM fluorescence staining, apoptosis by flow cytometry, and senescence by the senescence-associated β-galactosidase kit.

RESULTS

GPER was widely expressed in cervical cancer but not in its precursor lesions. The staining was predominantly cytoplasmic, although it was also important in the nucleus of the epithelial cells. G-1 inhibited proliferation, decreased the mitochondrial permeability, and increased the percentage of apoptosis in SiHa, HeLa, and C-33A. Only in C-33A, an increase of the cells in necrosis was observed, whereas SiHa was the only cell line in which senescence was evidenced.

CONCLUSION

GPER is a receptor associated with cervical cancer that inhibits the growth and induces different mechanisms of death in cells derived from uterine cervical cancer. It suggests that GPER can be considered a pharmacological target that prevents the development of cervical carcinogenesis.

The G Protein-Coupled Estrogen Receptor (GPER) Expression Correlates with Pro-Metastatic Pathways in ER-Negative Breast Cancer: A Bioinformatics Analysis

The G protein-coupled estrogen receptor (GPER, formerly known as GPR30) is a seven-transmembrane receptor that mediates estrogen signals in both normal and malignant cells. In particular, GPER has been involved in the activation of diverse signaling pathways toward transcriptional and biological responses that characterize the progression of breast cancer (BC). In this context, a correlation between GPER expression and worse clinical-pathological features of BC has been suggested, although controversial data have also been reported. In order to better assess the biological significance of GPER in the aggressive estrogen receptor (ER)-negative BC, we performed a bioinformatics analysis using the information provided by The Invasive Breast Cancer Cohort of The Cancer Genome Atlas (TCGA) project and Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) datasets. Gene expression correlation and the statistical analysis were carried out with R studio base functions and the tidyverse package. Pathway enrichment analysis was evaluated with Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway on the Database for Annotation, Visualization and Integrated Discovery (DAVID) website, whereas gene set enrichment analysis (GSEA) was performed with the R package phenoTest. The survival analysis was determined with the R package survivALL. Analyzing the expression data of more than 2500 primary BC, we ascertained that GPER levels are associated with pro-migratory and metastatic genes belonging to cell adhesion molecules (CAMs), extracellular matrix (ECM)-receptor interaction, and focal adhesion (FA) signaling pathways. Thereafter, evaluating the disease-free interval (DFI) in ER-negative BC patients, we found that the subjects expressing high GPER levels exhibited a shorter DFI in respect to those exhibiting low GPER levels. Overall, our results may pave the way to further dissect the network triggered by GPER in the breast malignancies lacking ER toward a better assessment of its prognostic significance and the action elicited in mediating the aggressive features of the aforementioned BC subtype.