Estrogen regulates miRNA expression: implication of estrogen receptor and miR-124/AKT2 in tumor growth and angiogenesis

Dynamics of serum exosome microRNA profile altered by chemically induced estropause and rescued by estrogen therapy in female mice

The decline in the ovarian reserve leads to menopause and reduced serum estrogens. MicroRNAs are small non-coding RNAs, which can regulate gene expression and be secreted by cells and trafficked in serum via exosomes. Serum miRNAs regulate tissue function and disease development. Therefore, the aim of this study was to identify miRNA profiles in serum exosomes of mice induced to estropause and treated with 17β-estradiol (E2). Female mice were divided into three groups including control (CTL), injected with 4-Vinylcyclohexene diepoxide (VCD), and injected with VCD plus E2 (VCD + E2). Estropause was confirmed by acyclicity and a significant reduction in the number of ovarian follicles (p < 0.05). Body mass gain during estropause was higher in VCD and VCD + E2 compared to CTL females (p = 0.02). Sequencing of miRNAs was performed from exosomes extracted from serum, and 402 miRNAs were detected. Eight miRNAs were differentially regulated between CTL and VCD groups, seven miRNAs regulated between CTL and VCD + E2 groups, and ten miRNAs regulated between VCD and VCD + E2 groups. Only miR-200a-3p and miR-200b-3p were up-regulated in both serum exosomes and ovarian tissue in both VCD groups, suggesting that these exosomal miRNAs could be associated with ovarian activity. In the hepatic tissue, only miR-370-3p (p = 0.02) was up-regulated in the VCD + E2 group, as observed in serum. Our results suggest that VCD-induced estropause and E2 replacement have an impact on the profile of serum exosomal miRNAs. The miR-200 family was increased in serum exosomes and ovarian tissue and may be a candidate biomarker of ovarian function.

Exploring miRNA Profiles in Colon Cancer: A Focus on miR101-3p, miR106a-5p, and miR326

Early diagnosis and prognosis of cancer progression through biomarker profiling are crucial in managing colon cancer patients. Our research aimed to investigate the expression of miR-101-3p, miR-106a-5p, and miR-326 in tumor and adjacent healthy tissues of colon cancer patients and determine their potential diagnostic utility. This study included 40 patients divided into four groups according to the TNM staging classification. MiRNA expression was analyzed using qRT-PCR. The results showed that miR-101-3p, miR-106a-5p, and miR-326 are overexpressed in adjacent healthy tissues but decrease in advanced cancer stages. MiR-106a-5p and miR-326 are strongly correlated with colon cancer severity. These findings suggest that miRNA profiling could be useful for early diagnosis and prognosis in colon cancer management.

MicroRNA-21: A critical underestimated molecule in diabetic retinopathy

Diabetes mellitus (DM) has grown in attention in recent years as a result of its debilitating complications and chronic disabilities. Diabetic retinopathy (DR) is a chronic microvascular complication of DM and is considered as the primary reason for blindness in adults. Early diagnosis of diabetes complications along with targeted therapy options are critical in avoiding morbidity and mortality associated with complications of diabetes. miR-21 is an important and widely studied non-coding-RNA (ncRNA) with considerable roles in various pathologic conditions including diabetic complications. miR-21 is one of the most elevated miRNAs in response to hyperglycemia and its role in angiogenesis is a major culprit of a wide range of disorders including DR. The main role of miR-21 in DR pathophysiology is believed to be through regulating angiogenesis in retina. This article aims to outline miR-21 biogenesis and distribution in human body along with discussions about its role in DR pathogenesis and its biomarker value in order to facilitate understanding of the new characteristics of miR-21 in DR management.

The various role of microRNAs in breast cancer angiogenesis, with a special focus on novel miRNA-based delivery strategies

After skin malignancy, breast cancer is the most widely recognized cancer detected in women in the United States. Breast cancer (BCa) can happen in all kinds of people, but it's much more common in women. One in four cases of cancer and one in six deaths due to cancer are related to breast cancer. Angiogenesis is an essential factor in the growth of tumors and metastases in various malignancies. An expanded level of angiogenesis is related to diminished endurance in BCa patients. This function assumes a fundamental part inside the human body, from the beginning phases of life to dangerous malignancy. Various factors, referred to as angiogenic factors, work to make a new capillary. Expanding proof demonstrates that angiogenesis is managed by microRNAs (miRNAs), which are small non-coding RNA with 19-25 nucleotides. MiRNA is a post-transcriptional regulator of gene expression that controls many critical biological processes. Endothelial miRNAs, referred to as angiomiRs, are probably concerned with tumor improvement and angiogenesis via regulation of pro-and anti-angiogenic factors. In this article, we reviewed therapeutic functions of miRNAs in BCa angiogenesis, several novel delivery carriers for miRNA-based therapeutics, as well as CRISPR/Cas9 as a targeted therapy in breast cancer.

BMPR2 Mutation and Metabolic Reprogramming in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension forms the first and most severe of the 5 categories of pulmonary hypertension. Disease pathogenesis is driven by progressive remodeling of peripheral pulmonary arteries, caused by the excessive proliferation of vascular wall cells, including endothelial cells, smooth muscle cells and fibroblasts, and perivascular inflammation. Compelling evidence from animal models suggests endothelial cell dysfunction is a key initial trigger of pulmonary vascular remodeling, which is characterised by hyperproliferation and early apoptosis followed by enrichment of apoptosis-resistant populations. Dysfunctional pulmonary arterial endothelial cells lose their ability to produce vasodilatory mediators, together leading to augmented pulmonary arterial smooth muscle cell responses, increased pulmonary vascular pressures and right ventricular afterload, and progressive right ventricular hypertrophy and heart failure. It is recognized that a range of abnormal cellular molecular signatures underpin the pathophysiology of pulmonary arterial hypertension and are enhanced by loss-of-function mutations in the BMPR2 gene, the most common genetic cause of pulmonary arterial hypertension and associated with worse disease prognosis. Widespread metabolic abnormalities are observed in the heart, pulmonary vasculature, and systemic tissues, and may underpin heterogeneity in responsivity to treatment. Metabolic abnormalities include hyperglycolytic reprogramming, mitochondrial dysfunction, aberrant polyamine and sphingosine metabolism, reduced insulin sensitivity, and defective iron handling. This review critically discusses published mechanisms linking metabolic abnormalities with dysfunctional BMPR2 (bone morphogenetic protein receptor 2) signaling; hypothesized mechanistic links requiring further validation; and their relevance to pulmonary arterial hypertension pathogenesis and the development of potential therapeutic strategies.

Molecular Mechanisms of Anti-Estrogen Therapy Resistance and Novel Targeted Therapies

Breast cancer (BC) is the most commonly diagnosed cancer in women, constituting one-third of all cancers in women, and it is the second leading cause of cancer-related deaths in the United States. Anti-estrogen therapies, such as selective estrogen receptor modulators, significantly improve survival in estrogen receptor-positive (ER+) BC patients, which represents about 70% of cases. However, about 60% of patients inevitably experience intrinsic or acquired resistance to anti-estrogen therapies, representing a major clinical problem that leads to relapse, metastasis, and patient deaths. The resistance mechanisms involve mutations of the direct targets of anti-estrogen therapies, compensatory survival pathways, as well as alterations in the expression of non-coding RNAs (e.g., microRNA) that regulate the activity of survival and signaling pathways. Although cyclin-dependent kinase 4/6 and phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) inhibitors have significantly improved survival, the efficacy of these therapies alone and in combination with anti-estrogen therapy for advanced ER+ BC, are not curative in advanced and metastatic disease. Therefore, understanding the molecular mechanisms causing treatment resistance is critical for developing highly effective therapies and improving patient survival. This review focuses on the key mechanisms that contribute to anti-estrogen therapy resistance and potential new treatment strategies alone and in combination with anti-estrogen drugs to improve the survival of BC patients.

Response to neoadjuvant chemotherapy in breast cancer: do microRNAs matter?

BACKGROUND

Conventionally, breast cancer (BC) prognosis and prediction of response to therapy are based on TNM staging, histological and molecular subtype, as well as genetic alterations. The role of various epigenetic factors has been elucidated in carcinogenesis. However, it is still unknown to what extent miRNAs affect the response to neoadjuvant chemotherapy (NACT). This pilot study is focused on evaluating the role of miR-34a, miR-124a, miR-155, miR-137 and miR-373 in response to NACT.

METHODS

That was a prospective study enrolling 34 patients with histologically confirmed BC of II-III stages. The median age of patients was 53 (47-59.8) years old, 70.6% of whom were HR-positive. MiRs levels were measured in the primary tumor before and after NACT. The response to therapy was assessed after surgery using the Miller-Payne scoring system. To establish the role of miRs in modulating response to NACT the Cox model was applied for analysis.

RESULTS

BC demonstrated a great variability of miRs expression before and after NACT with no strong links to tumor stage and molecular subtype. Only miR-124a and miR-373 demonstrated differential expression between malignant and normal breast tissues before and after therapy though these distinctions did not impact response to NACT. Besides miR-124a and miR-137 levels after NACT were found to be dependent on HR status. While miR-124a levels increased (p = 0.021) in the tumor tissue, the expression of miR-137 was downregulated (p = 0.041) after NACT in HR positive BC.

CONCLUSIONS

The study revealed differences in miR-124a and miR-373 expression after NACT in primary BC tissues. Although miRs levels did not impact the response to NACT, we found miR-124a and miR-137 levels to be related to hormonal sensitivity of BC.

Regulation of MicroRNAs

MicroRNAs are RNAs of about 18-24 nucleotides in lengths, which are found in the small noncoding RNA class and have a crucial role in the posttranscriptional regulation of gene expression, cellular metabolic pathways, and developmental events. These small but essential molecules are first processed by Drosha and DGCR8 in the nucleus and then released into the cytoplasm, where they cleaved by Dicer to form the miRNA duplex. These duplexes are bound by the Argonaute (AGO) protein to form the RNA-induced silencing complex (RISC) in a process called RISC loading. Transcription of miRNAs, processing with Drosha and DGCR8 in the nucleus, cleavage by Dicer, binding to AGO proteins and forming RISC are the most critical steps in miRNA biogenesis. Additional molecules involved in biogenesis at these stages can enhance or inhibit these processes, which can radically change the fate of the cell. Biogenesis is regulated by many checkpoints at every step, primarily at the transcriptional level, in the nucleus, cytoplasm, with RNA regulation, RISC loading, miRNA strand selection, RNA methylation/uridylation, and turnover rate. Moreover, in recent years, different regulation mechanisms have been discovered in noncanonical Drosha or Dicer-independent pathways. This chapter seeks answers to how miRNA biogenesis and function are regulated through both canonical and non-canonical pathways.

Akt Isoforms: A Family Affair in Breast Cancer

Simple Summary

Breast cancer is the second leading cause of cancer-related death in women in the United States. The Akt signaling pathway is deregulated in approximately 70% of patients with breast cancer. While targeting Akt is an effective therapeutic strategy for the treatment of breast cancer, there are several members in the Akt family that play distinct roles in breast cancer. However, the function of Akt isoforms depends on many factors. This review analyzes current progress on the isoform-specific functions of Akt isoforms in breast cancer.

Abstract

Akt, also known as protein kinase B (PKB), belongs to the AGC family of protein kinases. It acts downstream of the phosphatidylinositol 3-kinase (PI3K) and regulates diverse cellular processes, including cell proliferation, cell survival, metabolism, tumor growth and metastasis. The PI3K/Akt signaling pathway is frequently deregulated in breast cancer and plays an important role in the development and progression of breast cancer. There are three closely related members in the Akt family, namely Akt1(PKBα), Akt2(PKBβ) and Akt3(PKBγ). Although Akt isoforms share similar structures, they exhibit redundant, distinct as well as opposite functions. While the Akt signaling pathway is an important target for cancer therapy, an understanding of the isoform-specific function of Akt is critical to effectively target this pathway. However, our perception regarding how Akt isoforms contribute to the genesis and progression of breast cancer changes as we gain new knowledge. The purpose of this review article is to analyze current literatures on distinct functions of Akt isoforms in breast cancer.

Angioregulatory microRNAs in breast cancer: Molecular mechanistic basis and implications for therapeutic strategies

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Cancer-associated angiogenesis is a fundamental process in tumor growth and metastasis.

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Angioregulatory miRNA–target gene interaction is not only involved in sprouting vessels of breast tumors but also, trans-differentiation of breast cancer cells to endothelial cells in a process termed vasculogenic mimicry.

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Successful targeting of tumor angiogenesis is still a missing link in the treatment of Breast cancer (BC) due to the low effectiveness of anti-angiogenic therapies in this cancer.

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Response to anti-angiogenic therapeutics are controlled by a miRNAs, so the identification of interaction networks of miRNAs–targets can be applicable in determining anti-angiogeneic therapy and new biomarkers in BC.

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Angioregulatory miRNAs in breast cancer cells and their microenvironment have therapeutic potential in cancer treatment.

Background

Cancer-associated angiogenesis is a fundamental process in tumor growth and metastasis. A variety of signaling regulators and pathways contribute to establish neovascularization, among them as small endogenous non-coding RNAs, microRNAs (miRNAs) play prominent dual regulatory function in breast cancer (BC) angiogenesis.

Aim of Review

This review aims at describing the current state-of-the-art in BC angiogenesis-mediated by angioregulatory miRNAs, and an overview of miRNAs dysregulation association with the anti-angiogenic response in addition to potential clinical application of miRNAs-based therapeutics.

Key Scientific Concepts of Review

Angioregulatory miRNA–target gene interaction is not only involved in sprouting vessels of breast tumors but also, trans-differentiation of BC cells to endothelial cells (ECs) in a process termed vasculogenic mimicry. Using canonical and non-canonical angiogenesis pathways, the tumor cell employs the oncogenic characteristics such as miRNAs dysregulation to increase survival, proliferation, oxygen and nutrient supply, and treatment resistance. Angioregulatory miRNAs in BC cells and their microenvironment have therapeutic potential in cancer treatment. Although, miRNAs dysregulation can serve as tumor biomarker nevertheless, due to the association of miRNAs dysregulation with anti-angiogenic resistant phenotype, clinical benefits of anti-angiogenic therapy might be challenging in BC. Hence, unveiling the molecular mechanism underlying angioregulatory miRNAs sparked a booming interest in finding new treatment strategies such as miRNA-based therapies in BC.

Tumor Suppressive Effects of miR-124 and Its Function in Neuronal Development

MicroRNA-124 (miR-124) is strongly expressed in neurons, and its expression increases as neurons mature. Through DNA methylation in the miR-124 promoter region and adsorption of miR-124 by non-coding RNAs, miR-124 expression is known to be reduced in many cancer cells, especially with high malignancy. Recently, numerous studies have focused on miR-124 due to its promising tumor-suppressive effects; however, the overview of their results is unclear. We surveyed the tumor-suppressive effect of miR-124 in glial cell lineage cancers, which are the most frequently reported cancer types involving miR-124, and in lung, colon, liver, stomach, and breast cancers, which are the top five causes of cancer death. Reportedly, miR-124 not only inhibits proliferation and accelerates apoptosis, but also comprehensively suppresses tumor malignant transformation. Moreover, we found that miR-124 exerts its anti-tumor effects by regulating a wide range of target genes, most notably STAT3 and EZH2. In addition, when compared to the original role of miR-124 in neuronal development, we found that the miR-124 target genes that contribute to neuronal maturation share similarities with genes that cause cancer cell metastasis and epithelial-mesenchymal transition. We believe that the two apparently unrelated fields, cancer and neuronal development, can bring new discoveries to each other through the study of miR-124.

MicroRNA Regulation of Breast Cancer Stemness

Recent advances in our understanding of breast cancer have demonstrated that cancer stem-like cells (CSCs, also known as tumor-initiating cell (TICs)) are central for progression and recurrence. CSCs are a small subpopulation of cells present in breast tumors that contribute to growth, metastasis, therapy resistance, and recurrence, leading to poor clinical outcome. Data have shown that cancer cells can gain characteristics of CSCs, or stemness, through alterations in key signaling pathways. The dysregulation of miRNA expression and signaling have been well-documented in cancer, and recent studies have shown that miRNAs are associated with breast cancer initiation, progression, and recurrence through regulating CSC characteristics. More specifically, miRNAs directly target central signaling nodes within pathways that can drive the formation, maintenance, and even inhibition of the CSC population. This review aims to summarize these research findings specifically in the context of breast cancer. This review also discusses miRNAs as biomarkers and promising clinical therapeutics, and presents a comprehensive summary of currently validated targets involved in CSC-specific signaling pathways in breast cancer.

Activation of GPER by E2 promotes proliferation, invasion and migration of breast cancer cells by regulating the miR-124/CD151 pathway

Breast cancer is one of the most common malignancies worldwide and is responsible for a high mortality rate. However, the underlying pathological mechanism of breast cancer remains unclear. MicroRNAs (miRNAs/miRs) play critical roles in the progression of breast cancer. Recent studies have reported that miR-124/CD151 participates in the development of breast cancer. However, the exact molecular mechanism of miR-124/CD151 action in 17β-estradiol (E2)-treated breast cancer cells remains unknown. Thus, the present study aimed to investigate miR-124 and CD151 expression levels in MCF-7 cells treated with E2 via reverse transcription-quantitative PCR and western blot analyses. Bioinformatic analysis was performed to predict and identify whether CD151 is a potential target of miR-124. The Cell Counting Kit-8 and colony formation assays were performed to detect proliferation of MCF-7 cells. In addition, the invasive and migratory abilities of MCF-7 cells were assessed via the Transwell and wound healing assays, respectively. The results demonstrated that E2 downregulated miR-124 expression, while upregulating G protein -coupled estrogen receptor (GPER) expression in MCF-7 cells. Following treatment with the GPER antagonist, G15, miR-124 expression was significantly enhanced and E2-induced proliferation, invasion and migration of MCF-7 cells were notably inhibited. In addition, CD151 was confirmed as a direct target of miR-124. CD151 silencing remarkably suppressed the proliferation, invasion and migration of E2-induced MCF-7 cells. Taken together, these results suggest that upregulation of GPER expression induced by E2 promotes proliferation, invasion and migration of breast cancer cells by regulating the miR-124/CD151 pathway. Thus, the results of the present study provide a potential novel method for the treatment and prognosis of breast cancer.

Angiogenesis regulation by microRNAs and long non-coding RNAs in human breast cancer

MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are capable of regulating gene expression post-transcriptionally. Since the past decade, a number of in vitro, in vivo, and clinical studies reported the roles of these non-coding RNAs (ncRNAs) in regulating angiogenesis, an important cancer hallmark that is associated with metastases and poor prognosis. The specific roles of various miRNAs and lncRNAs in regulating angiogenesis in breast cancer, with particular focus on the downstream targets and signalling pathways regulated by these ncRNAs will be discussed in this review. In light of the recent trend in exploiting ncRNAs as cancer therapeutics, the potential use of miRNAs and lncRNAs as biomarkers and novel therapeutic agent against angiogenesis was also discussed.

Regulatory Interplay between miR-181a-5p and Estrogen Receptor Signaling Cascade in Breast Cancer

Simple Summary

Despite huge efforts in breast cancer care programs, patient’s survival rates greatly vary. Differences in response to therapy still represent the major challenge for clinicians and biologists. Define new anticancer mechanisms and innovative predictors for resistance could be a valid strategy to permanently defeat breast cancer. Here we propose the epigenetic based reprogramming of breast cancer, which leverages on the crosstalk between miR-181a-5p and Estrogen Receptor α. This simultaneously approach allows to induce miR-181a-5p and reduce the receptor expression, blocking the estrogen-dependent proliferative pathway underlying breast cancer progression. Since the epigenetic approach insists on transcriptional regulation, it is mostly independent of the acquired resistance mechanisms typically induced by prolonged endocrine therapy and therefore can be used as a sensitizer, neoadjuvant, or in combination with the standard in care treatments against breast cancer.

Abstract

The efficacy and side effects of endocrine therapy in breast cancer (BC) depend largely on estrogen receptor alpha (ERα) expression, the specific drug administered, and treatment scheduling. Although the benefits of endocrine therapy outweigh any adverse effects in the initial stages of BC, later- or advanced-stage tumors acquire resistance to treatments. The mechanisms underlying tumor resistance to therapy are still not well understood, posing a major challenge for BC patient care. Epigenetic regulation and miRNA expression may be involved in the switch from a treatment-sensitive to a treatment-resistant state and could provide a valid therapeutic strategy for ERα negative BC. Here, a hybrid lysine-specific histone demethylase inhibitor, MC3324, displaying selective estrogen receptor down-regulator-like activities in BC, was used to highlight the interplay between epigenetic and ERα signaling. MC3324 anticancer action is mediated by microRNA (miRNA) expression regulation, indicating an innovative function for this molecule. Integrated analysis suggests a crosstalk between estrogen signaling, ERα interactors, miRNAs, and their putative targets. Specifically, miR-181a-5p expression is regulated by MC3324 and has an impact on cellular levels of ERα. A comparison of breast tumor versus healthy mammary tissues confirmed the important role of miR-181a-5p in ERα regulation and points to its putative predictive function in BC therapy.

Non-coding RNAs regulate angiogenic processes

Angiogenesis has critical roles in numerous physiologic processes during embryonic and adult life such as wound healing and tissue regeneration. However, aberrant angiogenic processes have also been involved in the pathogenesis of several disorders such as cancer and diabetes mellitus. Vascular endothelial growth factor (VEGF) is implicated in the regulation of this process in several physiologic and pathologic conditions. Notably, several non-coding RNAs (ncRNAs) have been shown to influence angiogenesis through modulation of expression of VEGF or other angiogenic factors. In the current review, we summarize the function and characteristics of microRNAs and long non-coding RNAs which regulate angiogenic processes. Understanding the role of these transcripts in the angiogenesis can facilitate design of therapeutic strategies to defeat the pathogenic events during this process especially in the human malignancies. Besides, angiogenesis-related mechanisms can improve tissue regeneration after conditions such as arteriosclerosis, myocardial infarction and limb ischemia. Thus, ncRNA-regulated angiogenesis can be involved in the pathogenesis of several disorders.

Regulation of MicroRNA-497-Targeting AKT2 Influences Tumor Growth and Chemoresistance to Cisplatin in Lung Cancer

Background

MicroRNA-497 (miR-497) has been implicated in several cancers. Increasing studies demonstrate the role of AKT2 in cancers as an oncogene which is closely associated with tumor aggressiveness by enhancing cancer cell survival, migration and invasion However, miR-497/AKT2 axis in non-small cell lung cancer (NSCLC) remains unclear.

Methods

Quantitative real-time PCR (qRT-PCR) was used to quantify the expression of miR-497 and its target gene. The function of miR-497 in lung cancer was investigated through in vitro and in vivo assays (cell proliferation assay, cell migration assay, colony formation assay, flow cytometry assay, immunoblotting and tumorigenesis assay). Luciferase reporter assay was conducted to confirm the target gene of miR-497.

Results

In this study, we found that miR-497 was significantly downregulated in tumor tissues and blood samples of lung cancer patients. To understand the potential mechanism of miR-497 in inhibiting tumor growth, we showed that miR-497 blocked the activation of AKT2 and regulated cell proliferation, cell migration, colony formation and increases chemosensitivity of H1299 cells to cisplatin by inhibiting AKT2. MiR-497 also inhibited tumor growth and suppressed expression of AKT2 at the protein and mRNA levels in mouse xenograft tumors.

Conclusion

Taken together, our findings indicated that miR-497 suppresses the tumor growth by targeting AKT2, and the miR-497/AKT2 axis is a potential therapeutic target for NSCLC intervention.

Perspectives on the Role of Non-Coding RNAs in the Regulation of Expression and Function of the Estrogen Receptor

Estrogen receptors (ERs) comprise several nuclear and membrane-bound receptors with different tissue-specific functions. ERα and ERβ are two nuclear members of this family, whereas G protein-coupled estrogen receptor (GPER), ER-X, and Gq-coupled membrane estrogen receptor (Gq-mER) are membrane-bound G protein-coupled proteins. ERα participates in the development and function of several body organs such as the reproductive system, brain, heart and musculoskeletal systems. ERβ has a highly tissue-specific expression pattern, particularly in the female reproductive system, and exerts tumor-suppressive roles in some tissues. Recent studies have revealed functional links between both nuclear and membrane-bound ERs and non-coding RNAs. Several oncogenic lncRNAs and miRNAs have been shown to exert their effects through the modulation of the expression of ERs. Moreover, treatment with estradiol has been shown to alter the malignant behavior of cancer cells through functional axes composed of non-coding RNAs and ERs. The interaction between ERs and non-coding RNAs has functional relevance in several human pathologies associated with estrogen regulation, such as cancers, intervertebral disc degeneration, coronary heart disease and diabetes. In the current review, we summarize scientific literature on the role of miRNAs and lncRNAs on ER-associated signaling and related disorders.

Effect of heifer age on the granulosa cell transcriptome after ovarian stimulation

Genomic selection is accelerating genetic gain in dairy cattle. Decreasing generation time by using younger gamete donors would further accelerate breed improvement programs. Although ovarian stimulation of peripubertal animals is possible and embryos produced in vitro from the resulting oocytes are viable, developmental competence is lower than when sexually mature cows are used. The aim of the present study was to shed light on how oocyte developmental competence is acquired as a heifer ages. Ten peripubertal Bos taurus Holstein heifers underwent ovarian stimulation cycles at the ages of 8, 11 (mean 10.8) and 14 (mean 13.7) months. Collected oocytes were fertilised in vitro with spermatozoa from the same adult male. Each heifer served as its own control. The transcriptomes of granulosa cells recovered with the oocytes were analysed using microarrays. Differential expression of certain genes was measured using polymerase chain reaction. Principal component analysis of microarray data revealed that the younger the animal, the more distinctive the gene expression pattern. Using ingenuity pathway analysis (IPA) and NetworkAnalyst (www.networkanalyst.ca), the main biological functions affected in younger donors were identified. The results suggest that cell differentiation, inflammation and apoptosis signalling are less apparent in peripubertal donors. Such physiological traits have been associated with a lower basal concentration of LH.

Rs531564 polymorphism in microRNA-214 regulates interleukin-6R expression in anal fissure patients to affect the risk of anal abscess formation

BACKGROUND

Anal abscess is an important complication of anal fissure (AF), whereas interleukin-6R (IL-6R) has been implicated in the development of abscess. In this study, we aimed to explore the possible molecular mechanisms underlying the regulatory effects of miRNAs on IL-6R and other inflammatory factors related to the induction of anal abscess in AF.

METHODS

Bioinformatics analysis, luciferase assay, real-time polymerase chain reaction, and Western blot analysis were performed to identify the possible regulatory relationships between IL-6R and miR-124/miR-125a by comparing the differentiated expression of miR-125a, miR-124, tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), and IL-4 among different groups of AF patients.

RESULTS

IL-6R messenger RNA (mRNA) was identified as a target gene of miR-124 because the luciferase activity in cells cotransfected with wild-type IL-6R and miR-124 mimics was significantly reduced. In addition, the expression of IL-6R mRNA and protein was significantly inhibited in the presence of miR-124 or an IL-6R inhibitor, confirming the presence of a negative regulatory relationship between miR-124 and IL-6R. Moreover, miR-124 and inflammatory factors were differentially expressed in AF patients carrying different genotypes of rs531564 polymorphism.

CONCLUSIONS

miR-124 and inflammatory factors TNF-α, IFN-γ, and IL-4 may be used as indicators of anal abscess development in AF patients. In addition, miR-124 polymorphism rs531564 is involved with the pathogenesis of anal abscess in AF patients, and the presence of rs531564 may increase the incidence of anal abscess via upregulating the expression of IL-6R, TNF-α, IFN-γ, and IL-4.

Differential MicroRNA Landscape Triggered by Estrogens in Cancer Associated Fibroblasts (CAFs) of Primary and Metastatic Breast Tumors

Cancer associated fibroblasts (CAFs) play a main role in breast cancer progression and metastasis. Estrogens modulate in breast CAFs the expression of microRNAs (miRNAs) that are involved in the development of many tumors. In order to provide novel insights on the regulation of miRNAs by estrogens in breast cancer, we analyzed the expression of 754 miRNAs in CAFs obtained from primary mammary tumors and CAFs derived from a cutaneous breast cancer metastasis. Using the TaqMan™ Human MicroRNA Array, we found that 17β-estradiol (E2) modulates numerous peculiar and common miRNAs in CAFs derived from primary and the metastatic malignancies. In particular, we assessed that E2 modulates 133 miRNAs (41 up and 92 downregulated) in CAFs derived from primary breast tumors, whereas E2 modulates 415 miRNAs (399 up and 16 downregulated) in CAFs derived from a cutaneous metastasis of breast carcinoma. Therefore, a number of miRNAs three times higher in metastatic CAFs with respect to primary breast CAFs was found modulated by E2. Our findings shed new light on the cumulative regulation of miRNAs by E2 in the main players of the tumor microenvironment as CAFs. Moreover, our data may be taken into consideration that is useful toward innovative prognostic and therapeutic approaches in breast cancer progression.

The regulatory role of microRNAs in angiogenesis-related diseases

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression at a post-transcriptional level via either the degradation or translational repression of a target mRNA. They play an irreplaceable role in angiogenesis by regulating the proliferation, differentiation, apoptosis, migration and tube formation of angiogenesis-related cells, which are indispensable for multitudinous physiological and pathological processes, especially for the occurrence and development of vascular diseases. Imbalance between the regulation of miRNAs and angiogenesis may cause many diseases such as cancer, cardiovascular disease, aneurysm, Kawasaki disease, aortic dissection, phlebothrombosis and diabetic microvascular complication. Therefore, it is important to explore the essential role of miRNAs in angiogenesis, which might help to uncover new and effective therapeutic strategies for vascular diseases. This review focuses on the interactions between miRNAs and angiogenesis, and miRNA-based biomarkers in the diagnosis, treatment and prognosis of angiogenesis-related diseases, providing an update on the understanding of the clinical value of miRNAs in targeting angiogenesis.

Estradiol and the Development of the Cerebral Cortex: An Unexpected Role?

The cerebral cortex undergoes rapid folding in an "inside-outside" manner during embryonic development resulting in the establishment of six discrete cortical layers. This unique cytoarchitecture occurs via the coordinated processes of neurogenesis and cell migration. In addition, these processes are fine-tuned by a number of extracellular cues, which exert their effects by regulating intracellular signaling pathways. Interestingly, multiple brain regions have been shown to develop in a sexually dimorphic manner. In many cases, estrogens have been demonstrated to play an integral role in mediating these sexual dimorphisms in both males and females. Indeed, 17β-estradiol, the main biologically active estrogen, plays a critical organizational role during early brain development and has been shown to be pivotal in the sexually dimorphic development and regulation of the neural circuitry underlying sex-typical and socio-aggressive behaviors in males and females. However, whether and how estrogens, and 17β-estradiol in particular, regulate the development of the cerebral cortex is less well understood. In this review, we outline the evidence that estrogens are not only present but are engaged and regulate molecular machinery required for the fine-tuning of processes central to the cortex. We discuss how estrogens are thought to regulate the function of key molecular players and signaling pathways involved in corticogenesis, and where possible, highlight if these processes are sexually dimorphic. Collectively, we hope this review highlights the need to consider how estrogens may influence the development of brain regions directly involved in the sex-typical and socio-aggressive behaviors as well as development of sexually dimorphic regions such as the cerebral cortex.

Estrogen-induced miR-196a elevation promotes tumor growth and metastasis via targeting SPRED1 in breast cancer

BACKGROUND

Estrogen plays a critical role in breast cancer (BC) progression through estrogen receptor (ER)-mediated gene regulation. Emerging studies suggest that the malignant progress of BC cells is influenced by the cross talk between microRNAs (miRNAs) and ER-α signaling. However, the mechanism and functional linkage between estrogen and miRNAs remain unclear.

METHODS

The expression levels of miR-196a and SPRED1 in BC were tested by qRT-PCR in 46 paired BC and adjacent tissues and by the GEO datasets. The role of miR-196a in estrogen-induced BC development was examined by CCK-8 assay, wound healing assay, Matrigel invasion assay and tumorigenicity assay in nude mice. The binding site of ER-α in miR-196a promoter region was analyzed by ChIP-seq, ChIP assay and luciferase reporter assay. The potential targets of miR-196a in BC cells were explored using the luciferase reporter assay and western blot analysis, and the correlation between miR-196a and SPRED1 was analyzed by Spearman's correlation analysis in BC specimens and GEO dataset. TCGA BRCA data was used to characterize the ESR1 signatures according to MSigDB gene set.

RESULTS

The expression levels of miR-196a were higher in ER-positive (ER+) breast tumors compared to ER-negative (ER-) tumor tissue samples. Besides, miR-196a was involved in estrogen-induced BC cell proliferation, migration and invasion. Notably, the up-regulation of miR-196a was mediated by a direct interaction with estrogen receptor α (ER-α) but not estrogen receptor β (ER-β) in its promoter region, and miR-196a expression levels were positively correlated to ER-α signature scores. Furthermore, SPRED1 was a new direct target of miR-196a which participated in miR-196a-promoted BC development and was suppressed by ligand-activated ER-α signal pathway. Finally, forced expression of miR-196a induced tumor growth of MCF7 cells, while inhibition of miR-196a significantly suppressed the tumor progress in vivo.

CONCLUSIONS

Overall, the identification of estrogen/miR-196a/SPRED1 cascade will shed light on new molecular mechanism of estrogen signaling in BC development and therapy.

Blood and lung microRNAs as biomarkers of pulmonary tumorigenesis in cigarette smoke-exposed mice

Cigarette smoke (CS) is known to dysregulate microRNA expression profiles in the lungs of mice, rats, and humans, thereby modulating several pathways involved in lung carcinogenesis and other CS-related diseases. We designed a study aimed at evaluating (a) the expression of 1135 microRNAs in the lung of Swiss H mice exposed to mainstream CS during the first 4 months of life and thereafter kept in filtered air for an additional 3.5 months, (b) the relationship between lung microRNA profiles and histopathological alterations in the lung, (c) intergender differences in microRNA expression, and (d) the comparison with microRNA profiles in blood serum. CS caused multiple histopathological alterations in the lung, which were almost absent in sham-exposed mice. An extensive microRNA dysregulation was detected in the lung of CS-exposed mice. Modulation of microRNA profiles was specifically related to the histopathological picture, no effect being detected in lung fragments with non-neoplastic lung diseases (emphysema or alveolar epithelial hyperplasia), whereas a close association occurred with the presence and multiplicity of preneoplastic lesions (microadenomas) and benign lung tumors (adenomas). Three microRNAs regulating estrogen and HER2-dependent mechanisms were modulated in the lung of adenoma-bearing female mice. Blood microRNAs were also modulated in mice affected by early neoplastic lesions. However, there was a poor association between lung microRNAs and circulating microRNAs, which can be ascribed to an impaired release of mature microRNAs from the damaged lung. Studies in progress are evaluating the feasibility of analyzing blood microRNAs as a molecular tool for lung cancer secondary prevention.

MiR-124 aggravates failing hearts by suppressing CD151-facilitated angiogenesis in heart

Heart failure (HF) is the final common pathway of various cardiovascular diseases. Although it is well documented that reduction of cardiac angiogenesis contributes to the progression from adaptive cardiac hypertrophy to HF, the molecular mechanisms remain unknown. In the present study, we found that cardiac expression of miR-124 was increased in patients and mice with HF. Recombinant adeno-associated virus (rAAV)-mediated miR-124 over-expression aggravated angiotensin II (Ang II) infusion-induced cardiac dysfunction and abnormal cardiac angiogenesis in mice. In vitro, transfection of miR-124 mimics significantly promoted apoptosis and reduced viability, migration, tube formation, and nitric oxide release in endothelial cells. In addition, CD151 was identified as a direct target of miR-124. Endothelial cell injury caused by CD151 silencing was mimicked by miR-124 over-expression. Re-expression of CD151 attenuated miR-124-mediated suppression of cardiac angiogenesis and cardiac dysfunction in Ang II-treated mice. Our observations suggest that miR-124 is an important negative regulator of cardiac angiogenesis and cardiac function, likely by suppressing the expression of CD151 in heart cells. Modulation of miR-124 levels may provide new strategies and targets for HF therapy.

Exosomal miR-665 as a novel minimally invasive biomarker for hepatocellular carcinoma diagnosis and prognosis

Recent studies have shown that circulating microRNAs are potential biomarkers for various types of malignancies. The aim of this study was to investigate the feasibility of using serum exosomal microRNAs (miRNAs) as novel serological biomarkers for hepatocellular carcinoma (HCC) diagnosis and prognosis. Exosomes are small membranous vesicles (30–100 nm). Exosomal miR-665 levels in HCC patients were significantly higher than those in healthy subjects (P < 0.05), and exosomal miR-665 levels were significantly upregulated in tumours larger in size (> 5 cm), in tumours with local invasion and in those at an advanced clinical stage (stage III/IV) of HCC (P = 0.0042, 0.0197, and 0.0276, respectively). The survival time of the exosomal miR-665 high-expression group (n = 17) was significantly shorter than that of the low-expression group (n = 13) (P = 0.036). In addition, we found that HCC cell-derived exosomes promoted hepatoma cell proliferation and upregulated the expression level of proteins in the MAPK/ERK pathway in vitro and in vivo. This study suggests that serum exosomal miR-665 may be a novel minimally invasive biomarker for HCC diagnosis and prognosis.

Prolonged fasting elicits increased hepatic triglyceride accumulation in rats born to dexamethasone-treated mothers

We investigated the effect of dexamethasone during the last week of pregnancy on glucose and lipid metabolism in male offspring. Twelve-week old offspring were evaluated after fasting for 12-hours (physiological) and 60-hours (prolonged). Physiological fasting resulted in glucose intolerance, decreased glucose clearance after pyruvate load and increased PEPCK expression in rats born to dexamethasone-treated mothers (DEX). Prolonged fasting resulted in increased glucose tolerance and increased glucose clearance after pyruvate load in DEX. These modulations were accompanied by accumulation of hepatic triglycerides (TG). Sixty-hour fasted DEX also showed increased citrate synthase (CS) activity, ATP citrate lyase (ACLY) content, and pyruvate kinase 2 (pkm2), glucose transporter 1 (slc2a1) and lactate dehydrogenase-a (ldha) expressions. Hepatic AKT2 was increased in 60-hour fasted DEX, in parallel with reduced miRNAs targeting the AKT2 gene. Altogether, we show that metabolic programming by prenatal dexamethasone is characterized by an unexpected hepatic TG accumulation during prolonged fasting. The underlying mechanism may depend on increased hepatic glycolytic flux due to increased pkm2 expression and consequent conversion of pyruvate to non-esterified fatty acid synthesis due to increased CS activity and ACLY levels. Upregulation of AKT2 due to reduced miRNAs may serve as a permanent mechanism leading to increased pkm2 expression.

Let-7a inhibits migration, invasion and tumor growth by targeting AKT2 in papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is the most common endocrine malignancy. Increasing evidence showed that microRNAs (miRNAs) play an important role in the PTC progression. In our study, the result showed that let-7a is significantly downregulated in PTC tissues and thyroid cancer cell lines. Overexpression of let-7a suppressed PTC cell proliferation, migration and invasion. Interestingly, we found that AKT2 was a direct target of let-7a and the expression levels of AKT2 were also observed to inversely correlate with let-7a expression in PTC tissues. Furthermore, enhancing AKT2 expression partially reversed the inhibitory effects of let-7a in PTC. Taken together, these findings suggest that let-7a acts as a novel suppressor by targeting the AKT2 gene and might be a candidate target for the development of novel therapeutic strategies to treat papillary thyroid carcinoma.

Aging and serum exomiR content in women-effects of estrogenic hormone replacement therapy

Exosomes participate in intercellular messaging by transporting bioactive lipid-, protein- and RNA-molecules and -complexes. The contents of the exosomes reflect the physiological status of an individual making exosomes promising targets for biomarker analyses. In the present study we extracted exosome microRNAs (exomiRs) from serum samples of premenopausal women (n = 8) and monozygotic postmenopausal twins (n = 10 female pairs), discordant for the use of estrogenic hormone replacement therapy (HRT), in order to see whether the age or/and the use of HRT associates with exomiR content. A total of 241 exomiRs were detected by next generation sequencing, 10 showing age, 14 HRT and 10 age +HRT -related differences. When comparing the groups, differentially expressed miRs were predicted to affect cell proliferation processes showing inactivation with younger age and HRT usage. MiR-106-5p, -148a-3p, -27-3p, -126-5p, -28-3p and -30a-5p were significantly associated with serum 17β-estradiol. MiRs formed two hierarchical clusters being indicative of positive or negative health outcomes involving associations with body composition, serum 17β-estradiol, fat-, glucose- and inflammatory markers. Circulating exomiR clusters, obtained by NGS, could be used as indicators of metabolic and inflammatory status affected by hormonal changes at menopause. Furthermore, the individual effects of HRT-usage could be evaluated based on the serum exomiR signature.

17β-Estradiol Enhances Vascular Endothelial Ets-1/miR-126-3p Expression: The Possible Mechanism for Attenuation of Atherosclerosis

CONTEXT

Endothelial microRNA 126 (miR-126) attenuates the development of atherosclerosis (AS). However, there is no evidence showing the role of miR-126 in estrogen's antiatherogenic effects.

OBJECTIVE

We hypothesized that 17β-estradiol (E2) modulates miR-126 expression and thus may improve endothelial function and retard AS development.

DESIGN/SETTING/PARTICIPANTS

This was a prospective cohort study of 12 healthy regularly menstruating female volunteers. ApoE-/- mice were used as the atherosclerosis model and human umbilical vascular endothelial cells (HUVECs) were cultured as the cell model.

MAIN OUTCOME MEASURES

Serum hormones and miR-126-3p levels were measured up to 3 times for 1 cycle. Real-time polymerase chain reaction, histology for atherosclerotic lesions, immunofluorescence, luciferase assay, transfection experiments, cell proliferation, migration and tube formation assay, and western blot were performed.

RESULTS

Serum concentrations of miR-126-3p in cycling women were higher at the ovulatory and luteal phases than in the follicular phase, and they were positively correlated with E2 values. Administration of miR-126-3p mimics to ApoE-/- mice-attenuated atherogenesis, and antagomir-126-3p partially reversed the protective effect of E2 on atherogenesis. In HUVECs, E2 increased miR-126-3p expression via upregulation of Ets-1 (a transcription factor for miR-126). c-Src/Akt signaling was important for E2-mediated expression of Ets-1/miR-126. E2 decreased expression of miR-126-3p target Spred1 (a protein that inhibits mitogenic signaling). Overexpression of Spred1 partially blocked enhancement of endothelial cell proliferation, migration, and tube formation by E2. Additionally, E2 regulates miR-126-3p-mediated expression of vascular cell adhesion molecule-1 to inhibit monocyte adhesion into HUVECs.

CONCLUSIONS

E2 protection against atherogenesis is possibly mediated by Ets-1/miR-126.

miR-148a-3p represses proliferation and EMT by establishing regulatory circuits between ERBB3/AKT2/c-myc and DNMT1 in bladder cancer

miR-148a-3p downregulation has emerged as a critical factor in cancer progression yet, the underlying mechanisms of miR-148a-3p expression pattern and its function in bladder cancer remains to be elucidated. Here, we illustrate that miR-148a-3p is frequently downregulated in bladder cancer and that its expression may be regulated by DNA methylation. DNA methyltransferase 1 (DNMT1) and miR-148a-3p function in a positive feedback loop in bladder cancer. miR-148a-3p overexpression functions as a tumor suppressor in bladder cancer cells. miR-148a-3p inhibits bladder cancer cell proliferation and epithelial–mesenchymal transition (EMT) by regulating ERBB3/AKT2/c-myc and ERBB3/AKT2/Snail signaling. ERBB3, DNMT1 and AKT2 are downstream miR-148a-3p target genes. Furthermore, the miR-148a-3p/ERBB3/AKT2/c-myc signaling axis establishes a positive feedback loop in the regulation of bladder cancer. Taken together, our study demonstrates novel regulatory circuits involving miR-148a-3p/ERBB3/AKT2/c-myc and DNMT1 that controls bladder cancer progression, which may be useful in the development of more effective therapies against bladder cancer.

miR-148a suppresses human renal cell carcinoma malignancy by targeting AKT2

MicroRNA-148a (miR-148a) has been reported to be deregulated in different tumor types, whereas the biological function of miR-148a in renal cell carcinoma (RCC) largely remains unexplored. In the present study we investigated the clinical significance, biological effects, and the underlying molecular mechanisms of miR-148 in RCC. Here, we showed that miR-148a was significantly downregulated in RCC tissues and cell lines. Low expression of miR-148a in RCC tissues was associated with large tumor size, advanced TNM stage, and lymph node metastasis. Functional assays revealed that overexpression of miR-148a significantly inhibited RCC cell proliferation, colony formation, migration and invasion in vitro and suppressed RCC xenograft tumor growth in vivo. In addition, using quantitative RT-PCR (qRT-PCR), western blot analysis and luciferase reporter assays, AKT2 was confirmed to be a direct target of miR-148a. AKT2 expression was upregulated, and was negatively correlated with miR-148a expression in RCC tissues (r=-0.641, P<0.001). Silencing of AKT2 phenotypically copied miR-148a-induced phenotypes, whereas re-expression of AKT2 reversed the suppressive effects of miR-148a in RCC cells. Further mechanistic investigations showed that miR-148a exerted its antitumor activity via inhibition of the AKT pathway in vitro and in vivo. Taken together, these findings suggest that miR-148a functions as tumor suppressor in RCC by targeting AKT2.