microRNA Regulation in Estrogen Receptor-Positive Breast Cancer and Endocrine Therapy

All-trans-retinoic acid modulates glycolysis via H19 and telomerase: the role of mir-let-7a in estrogen receptor-positive breast cancer cells

BACKGROUND

Breast cancer (BC) is the most commonly diagnosed cancer in women. Treatment approaches that differ between estrogen-positive (ER+) and triple-negative BC cells (TNBCs) and may subsequently affect cancer biomarkers, such as H19 and telomerase, are an emanating delight in BC research. For instance, all-trans-Retinoic acid (ATRA) could represent a potent regulator of these oncogenes, regulating microRNAs, mostly let-7a microRNA (miR-let-7a), which targets the glycolysis pathway, mainly pyruvate kinase M2 (PKM2) and lactate dehydrogenase A (LDHA) enzymes. Here, we investigated the potential role of ATRA in H19, telomerase, miR-let-7a, and glycolytic enzymes modulation in ER + and TNBC cells.

METHODS

MCF-7 and MDA-MB-231 cells were treated with 5 µM ATRA and/or 100 nM fulvestrant. Then, ATRA-treated or control MCF-7 cells were transfected with either H19 or hTERT siRNA. Afterward, ATRA-treated or untreated MDA-MB-231 cells were transfected with estrogen receptor alpha ER(α) or beta ER(β) expression plasmids. RNA expression was evaluated by RT‒qPCR, and proteins were assessed by Western blot. PKM2 activity was measured using an NADH/LDH coupled enzymatic assay, and telomerase activity was evaluated with a quantitative telomeric repeat amplification protocol assay. Student's t-test or one-way ANOVA was used to analyze data from replicates.

RESULTS

Our results showed that MCF-7 cells were more responsive to ATRA than MDA-MB-231 cells. In MCF-7 cells, ATRA and/or fulvestrant decreased ER(α), H19, telomerase, PKM2, and LDHA, whereas ER(β) and miR-let-7a increased. H19 or hTERT knockdown with or without ATRA treatment showed similar results to those obtained after ATRA treatment, and a potential interconnection between H19 and hTERT was found. However, in MDA-MB-231 cells, RNA expression of the aforementioned genes was modulated after ATRA and/or fulvestrant, with no significant effect on protein and activity levels. Overexpression of ER(α) or ER(β) in MDA-MB-231 cells induced telomerase activity, PKM2 and LDHA expression, in which ATRA treatment combined with plasmid transfection decreased glycolytic enzyme expression.

CONCLUSIONS

To the best of our knowledge, our study is the first to elucidate a new potential interaction between the estrogen receptor and glycolytic enzymes in ER + BC cells through miR-let-7a.

The role of miRNAs as biomarkers in breast cancer

Breast cancer (BC) is the second most common cause of deaths reported in women worldwide, and therefore there is a need to identify BC patients at an early stage as timely diagnosis would help in effective management and appropriate monitoring of patients. This will allow for proper patient monitoring and effective care. However, the absence of a particular biomarker for BC early diagnosis and surveillance makes it difficult to accomplish these objectives. miRNAs have been identified as master regulators of the molecular pathways that are emphasized in various tumors and that lead to the advancement of malignancies. Small, non-coding RNA molecules known as miRNAs target particular mRNAs to control the expression of genes. miRNAs dysregulation has been linked to the start and development of a number of human malignancies, including BC, since there is compelling evidence that miRNAs can function as tumor suppressor genes or oncogenes. The current level of knowledge on the role of miRNAs in BC diagnosis, prognosis, and treatment is presented in this review. miRNAs can regulate the tumorigenesis of BC through targeting PI3K pathway and can be used as prognostic or diagnostic biomarkers for BC therapy. Some miRNAs, like miR-9, miR-10b, and miR-17-5p, are becoming known as biomarkers of BC for diagnosis, prognosis, and therapeutic outcome prediction. Other miRNAs, like miR-30c, miR-187, and miR-339-5p, play significant roles in the regulation of hallmark functions of BC, including invasion, metastasis, proliferation, resting death, apoptosis, and genomic instability. Other miRNAs, such as miR-155 and miR-210, are circulating in bodily fluids and are therefore of interest as novel, conveniently accessible, reasonably priced, non-invasive methods for the customized care of patients with BC.

Systems genetics and bioinformatics analyses using ESR1-correlated genes identify potential candidates underlying female bone development

Estrogen receptor α (ESR1) is involved in E2 signaling and plays a major role in postmenopausal bone loss. However, the molecular network underlying ESR1 has not been explored. We used systems genetics and bioinformatics to identify important genes associated with Esr1 in postmenopausal bone loss. We identified ~2300 Esr1-coexpressed genes in female BXD bone femur, functional analysis of which revealed 'osteoblast signaling' as the most enriched pathway. PPI network led to the identification of 25 'female bone candidates'. The gene-regulatory analysis revealed RUNX2 as a key TF. ANKRD1 and RUNX2 were significantly different between osteoporosis patients and healthy controls. Sp7, Col1a1 and Pth1r correlated with multiple femur bone phenotypes in BXD mice. miR-3121-3p targeted Csf1, Ankrd1, Sp7 and Runx2. β-estradiol treatment markedly increased the expression of these candidates in mouse osteoblast. Our study revealed that Esr1-correlated genes Ankrd1, Runx2, Csf1 and Sp7 may play important roles in female bone development.

Regulation of mRNA translation by estrogen receptor in breast cancer

Breast cancer is one of the leading causes of cancer-related fatalities and the most often diagnosed malignancy in women globally. Dysregulation of sex hormone signaling pathways mediated by the estrogen receptor (ER) in breast cancer is well characterized. Although ER is known to promote cell growth and survival by altering gene transcription, recent research suggests that its effects in cancers are also mediated through dysregulation of protein synthesis. This implies that ER can coordinately affect gene expression through both translational and transcriptional pathways, leading to the development of malignancy. In this review, we will cover the current understanding of how the ER controls mRNA translation in breast cancer and discuss any potential clinical implications of this phenomenon.

ASSOCIATION OF miRNA EXPRESSION PATTERN WITH OUTCOME OF LETROZOLE THERAPY IN BREAST CANCER PATIENTS

Breast cancer (BC) remains the most prevalent tumor and the leading cause of death among women worldwide, despite the advancements in diagnosis and new treatments. A significant challenge in BC treatment is the acquired or de novo resistance of tumors to systemic therapy. To overcome this obstacle, personalized treatment is needed, with a focus on finding biomarkers capable of predicting the response to therapy. MicroRNAs (miRNAs) have emerged as potential markers due to their diverse clinical applications.

AIM

To examine the potential prognostic significance of miR-125b-2, -155, -221, and -320a expression in the tumor cells of individuals with hormone-dependent BC before undergoing neoadjuvant hormonal therapy.

MATERIALS AND METHODS

The study is based on a retrospective analysis of the treatment outcome of 56 patients with stage II-III locally disseminated hormone-dependent BC. The real-time quantitative reverse transcription polymerase chain reaction was performed on the biopsy material to assess the expression of miR-125b-2, -155, and -221 before neoadjuvant hormonal therapy with aromatase inhibi- tor letrozole to predict clinical response.

RESULTS

Most HER2/neu+ BC patients had low levels of miR-155 and miR-221 expression in tumor biopsy specimens. Tumors that responded well to letrozole exhibited lower levels of miR-125b-2 and miR-221 compared to non-responsive tumors.

CONCLUSIONS

miR-125b-2, -155, and -221 expres- sion can predict resistance to the letrozole treatment of BC.

17β-estradiol promotes extracellular vesicle release and selective miRNA loading in ERα-positive breast cancer

The causes and consequences of abnormal biogenesis of extracellular vesicles (EVs) are not yet well understood in malignancies, including in breast cancers (BCs). Given the hormonal signaling dependence of estrogen receptor-positive (ER+) BC, we hypothesized that 17β-estradiol (estrogen) might influence EV production and microRNA (miRNA) loading. We report that physiological doses of 17β-estradiol promote EV secretion specifically from ER+ BC cells via inhibition of miR-149-5p, hindering its regulatory activity on SP1, a transcription factor that regulates the EV biogenesis factor nSMase2. Additionally, miR-149-5p downregulation promotes hnRNPA1 expression, responsible for the loading of let-7's miRNAs into EVs. In multiple patient cohorts, we observed increased levels of let-7a-5p and let-7d-5p in EVs derived from the blood of premenopausal ER+ BC patients, and elevated EV levels in patients with high BMI, both conditions associated with higher levels of 17β-estradiol. In brief, we identified a unique estrogen-driven mechanism by which ER+ BC cells eliminate tumor suppressor miRNAs in EVs, with effects on modulating tumor-associated macrophages in the microenvironment.

Genetic and Epigenetic Basis of Drug-Induced Liver Injury

Drug-induced liver injury (DILI) is a rare but severe adverse drug reaction seen in pharmacotherapy and a major cause of postmarketing drug withdrawals. Advances in genome-wide studies indicate that genetic and epigenetic diversity can lead to inter-individual differences in drug response and toxicity. It is necessary to identify how the genetic variations, in the presence of environmental factors, can contribute to development and progression of DILI. Studies on microRNA, histone modification, DNA methylation, and single nucleotide polymorphisms related to DILI were retrieved from databases and were analyzed for the current research and updated to develop this narrative review. We have compiled some of the major genetic, epigenetic, and pharmacogenetic factors leading to DILI. Many validated genetic risk factors of DILI, such as variants of drug-metabolizing enzymes, HLA alleles, and some transporters were identified. In conclusion, these studies provide useful information in risk alleles identification and on implementation of personalized medicine.

Non-Coding RNAs Modulating Estrogen Signaling and Response to Endocrine Therapy in Breast Cancer

The largest part of human DNA is transcribed into RNA that does not code for proteins. These non-coding RNAs (ncRNAs) are key regulators of protein-coding gene expression and have been shown to play important roles in health, disease and therapy response. Today, endocrine therapy of ERα-positive breast cancer (BC) is a successful treatment approach, but resistance to this therapy is a major clinical problem. Therefore, a deeper understanding of resistance mechanisms is important to overcome this resistance. An increasing amount of evidence demonstrate that ncRNAs affect the response to endocrine therapy. Thus, ncRNAs are considered versatile biomarkers to predict or monitor therapy response. In this review article, we intend to give a summary and update on the effects of microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) on estrogen signaling in BC cells, this pathway being the target of endocrine therapy, and their role in therapy resistance. For this purpose, we reviewed articles on these topics listed in the PubMed database. Finally, we provide an assessment regarding the clinical use of these ncRNA types, particularly their circulating forms, as predictive BC biomarkers and their potential role as therapy targets to overcome endocrine resistance.

Estrogen receptor 1 appears essential for fetal viability in a murine model of premature birth

PROBLEM

Protective effects for adult neurological disorders have been attributed to sex hormones. Using a murine model of prematurity, we evaluated the role of estrogen signaling in the process of perinatal brain injury following exposure to intrauterine inflammation.

METHOD OF STUDY

Intrauterine lipopolysaccharide (LPS) was used to invoke preterm labor and fetal neuroinflammation. Fetal brains were analyzed for changes in Esr1, Esr2 and Cyp19. Dams heterozygous for the Esr1 knockout allele were also given intrauterine LPS to compare delivery and offspring viability to wild type controls.

RESULTS

The upregulation in inflammatory cytokines was accompanied by an increase in Esr1 and Esr2 transcripts, though protein levels declined. Cyp19 did not differ by mRNA or protein abundance. Offspring from Esr1 mutants were larger, had a longer gestation and significantly greater mortality.

CONCLUSIONS

Estrogen signaling is altered in the fetal brains of preterm offspring exposed to neuroinflammatory injury. The reduction of Esr1 and Esr2 proteins with LPS suggests that these proteins are degraded. It is possible that transcriptional upregulation of Esr1 and Esr2 occurs to compensate for the loss of these proteins. Alternatively, the translation of Esr1 and Esr2 mRNAs may be disrupted with LPS while a feedback mechanism upregulates transcription. Intact Esr1 signaling is also associated with early preterm delivery following exposure to intrauterine LPS. A loss of one Esr1 allele delays this process, but appears to do so at the cost of fetal viability. These results suggest estrogen signaling plays opposing roles between maternal and fetal responses to preterm birth.

Cell State Transitions and Phenotypic Heterogeneity in Luminal Breast Cancer Implicating MicroRNAs as Potential Regulators

Luminal breast cancer subtypes respond poorly to endocrine and trastuzumab treatments due to cellular heterogeneity arising from the phenotype transitions, accounted for mainly by the loss of receptor expression. The origins of basal-like and human epidermal growth factor receptor 2 (HER2)-overexpressing breast cancer subtypes have been attributed to genetic and protein modifications in stem-like cells and luminal progenitor cell populations, respectively. The post-transcriptional regulation of protein expression is known to be influenced by microRNAs (miRNAs) that are deemed to be master regulators of several biological processes in breast tumorigenesis and progression. Our objective was to identify the fractions of luminal breast cancer cells that share stemness potentials and marker profiles and to elucidate the molecular regulatory mechanism that drives transitions between fractions, leading to receptor discordances. Established breast cancer cell lines of all prominent subtypes were screened for the expression of putative cancer stem cell (CSC) markers and drug transporter proteins using a side population (SP) assay. Flow-cytometry-sorted fractions of luminal cancer cells implanted in immunocompromised mice generated a pre-clinical estrogen receptor alpha (ERα+) animal model with multiple tumorigenic fractions displaying differential expression of drug transporters and hormone receptors. Despite an abundance of estrogen receptor 1 (ESR1) gene transcripts, few fractions transitioned to the triple-negative breast cancer (TNBC) phenotype with a visible loss of ER protein expression and a distinct microRNA expression profile that is reportedly enriched in breast CSCs. The translation of this study has the potential to provide novel therapeutic miRNA-based targets to counter the dreaded subtype transitions and the failure of antihormonal therapies in the luminal breast cancer subtype.

Comparative Analysis of Transcriptomic Changes including mRNA and microRNA Expression Induced by the Xenoestrogens Zearalenone and Bisphenol A in Human Ovarian Cells

Xenoestrogens are natural or synthetic compounds that mimic the effect of endogenous estrogens and might cause cancer. We aimed to compare the global transcriptomic response to zearalenone (ZEA; mycotoxin) and bisphenol A (BPA; plastic additive) with the effect of physiological estradiol (E2) in the PEO1 human ovarian cell line by mRNA and microRNA sequencing. Estrogen exposure induced remarkable transcriptomic changes: 308, 288 and 63 genes were upregulated (log₂FC > 1); 292, 260 and 45 genes were downregulated (log₂FC < -1) in response to E2 (10 nM), ZEA (10 nM) and BPA (100 nM), respectively. Furthermore, the expression of 13, 11 and 10 miRNAs changed significantly (log₂FC > 1, or log₂FC < -1) after exposure to E2, ZEA and BPA, respectively. Functional enrichment analysis of the significantly differentially expressed genes and miRNAs revealed several pathways related to the regulation of cell proliferation and migration. The effect of E2 and ZEA was highly comparable: 407 genes were coregulated by these molecules. We could identify 83 genes that were regulated by all three treatments that might have a significant role in the estrogen response of ovarian cells. Furthermore, the downregulation of several miRNAs (miR-501-5p, let-7a-2-3p, miR-26a-2-3p, miR-197-5p and miR-582-3p) was confirmed by qPCR, which might support the proliferative effect of estrogens in ovarian cells.

Obesity as a Risk Factor for Breast Cancer-The Role of miRNA

Breast cancer (BC) is the most common cancer diagnosed among women in the world, with an ever-increasing incidence rate. Due to the dynamic increase in the occurrence of risk factors, including obesity and related metabolic disorders, the search for new regulatory mechanisms is necessary. This will help a complete understanding of the pathogenesis of breast cancer. The review presents the mechanisms of obesity as a factor that increases the risk of developing breast cancer and that even initiates the cancer process in the female population. The mechanisms presented in the paper relate to the inflammatory process resulting from current or progressive obesity leading to cell metabolism disorders and disturbed hormonal metabolism. All these processes are widely regulated by the action of microRNAs (miRNAs), which may constitute potential biomarkers influencing the pathogenesis of breast cancer and may be a promising target of anti-cancer therapies.

Suppressing the PI3K/AKT Pathway by miR-30d-5p Mimic Sensitizes Ovarian Cancer Cells to Cell Death Induced by High-Dose Estrogen

MicroRNAs are short non-coding RNA molecules that are involved in tumor development and are considered to be promising candidates in cancer therapy. Here, we studied the role of miR-30s in the pathophysiology of ovarian cancer. According to our results miR-30a-5p, miR-30d-5p, and miR-30e-5p were overexpressed in the estrogen receptor α (ERα)-expressing PEO1 cell line compared to A2780 that lacks this receptor. Furthermore, the expression of miR-30a-5p, miR-30d-5p, and miR-30e-5p were induced in response to high-dose estrogen treatment in PEO1 where intensive cell death was observed according to the induction of apoptosis and autophagy. Lacking or blocking ERα function reduced tolerance to high-dose estrogen that suggests the importance of ERα-mediated estrogen response in the maintenance of proliferation. MiR-30d-5p mimic reduced cell proliferation in both A2780 and PEO1. Furthermore, it decreased the tolerance of PEO1 cells to high-dose estrogen by blocking the ERα-mediated estrogen response. This was accompanied by decreased SOX4 expression that is thought to be involved in the regulation of the PI3K/AKT pathway. Blocking this pathway by AZD8835 led to the same results. MiR-30d-5p or AZD8835 sensitized PEO1 cells to tamoxifen. We suggest that miR-30d-5p might be a promising candidate in the therapy of ovarian cancer.

Predictors of fulvestrant long-term benefit in hormone receptor-positive/HER2 negative advanced breast cancer

We retrospectively investigated in women treated with fulvestrant for HR+/HER2 negative advanced breast cancer clinical, pathological and molecular features associated with long-term benefit from treatment defined as being progression-free at 18 months. Specifically, we analyzed on formalin-fixed paraffin-embedded tumor samples ESR1 and PI3KCA mutations and miRNAs profiles. 59 patients were evaluable (median age of 67 years, range 32-92). 18-month PFS rate was 27%; the lack of visceral metastases significantly predicted the likelihood of being progression-free at 18 months, while PI3KCA mutations, found in 36% of patients, were not associated with 18-month PFS. As of miRNAs, miR-549a, miR-644a, miR-16-5p were negatively while let-7c-5p was positively associated with 18-month PFS. In addition, miR-520d-3p and miR-548g-3p values were significantly lower while miR-603, miR-181a-5p and miR-199a-miR-199b-3p values were significantly higher in patients achieving 18-month PFS. In silico analysis of targets modulated by these two latter groups of miRNAs show that in patients achieving 18-month PFS the Hippo and Wnt signaling pathways were predicted to be upregulated while endocrine resistance was potentially repressed by miR-603, miR-181a-5p and miR-199a-miR-199b-3p. Our results provide additional clues on the molecular mechanisms involved in fulvestrant activity and resistance. Underlying pathways should be further elucidated and confirmed in larger cohorts.

Epigenetic Regulation of Estrogen Receptor Genes' Expressions in Adipose Tissue in the Course of Obesity

Estrogen affects adipose tissue function. Therefore, this study aimed at assessing changes in the transcriptional activity of estrogen receptor (ER) α and β genes (ESR1 and ESR2, respectively) in the adipose tissues of obese individuals before and after weight loss and verifying whether epigenetic mechanisms were involved in this phenomenon. ESR1 and ESR2 mRNA and miRNA levels were evaluated using real-time PCR in visceral (VAT) and subcutaneous adipose tissue (SAT) of 78 obese (BMI > 40 kg/m2) and 31 normal-weight (BMI = 20−24.9 kg/m2) individuals and in 19 SAT samples from post-bariatric patients. ESR1 and ESR2 methylation status was studied using the methylation-sensitive digestion/real-time PCR method. Obesity was associated with a decrease in mRNA levels of both ERs in SAT (p < 0.0001) and ESR2 in VAT (p = 0.0001), while weight loss increased ESR transcription (p < 0.0001). Methylation levels of ESR1 and ESR2 promoters were unaffected. However, ESR1 mRNA in the AT of obese subjects correlated negatively with the expression of hsa-miR-18a-5p (rs = −0.444), hsa-miR-18b-5p (rs = −0.329), hsa-miR-22-3p (rs = −0.413), hsa-miR-100-5p (rs = −0.371), and hsa-miR-143-5p (rs = −0.289), while the expression of ESR2 in VAT correlated negatively with hsa-miR-576-5p (rs = −0.353) and in SAT with hsa-miR-495-3p (rs = −0.308). In conclusion, obesity-associated downregulation of ER mRNA levels in adipose tissue may result from miRNA interference.

Mutual exclusivity of ESR1 and TP53 mutations in endocrine resistant metastatic breast cancer

Both TP53 and ESR1 mutations occur frequently in estrogen receptor positive (ER+) metastatic breast cancers (MBC) and their distinct roles in breast cancer tumorigenesis and progression are well appreciated. Recent clinical studies discovered mutual exclusivity between TP53 and ESR1 mutations in metastatic breast cancers; however, mechanisms underlying this intriguing clinical observation remain largely understudied and unknown. Here, we explored the interplay between TP53 and ESR1 mutations using publicly available clinical and experimental data sets. We first confirmed the robust mutational exclusivity using six independent cohorts with 1,056 ER+ MBC samples and found that the exclusivity broadly applies to all ER+ breast tumors regardless of their clinical and distinct mutational features. ESR1 mutant tumors do not exhibit differential p53 pathway activity, whereas we identified attenuated ER activity and expression in TP53 mutant tumors, driven by a p53-associated E2 response gene signature. Further, 81% of these p53-associated E2 response genes are either direct targets of wild-type (WT) p53-regulated transactivation or are mutant p53-associated microRNAs, representing bimodal mechanisms of ER suppression. Lastly, we analyzed the very rare cases with co-occurrences of TP53 and ESR1 mutations and found that their simultaneous presence was also associated with reduced ER activity. In addition, tumors with dual mutations showed higher levels of total and PD-L1 positive macrophages. In summary, our study utilized multiple publicly available sources to explore the mechanism underlying the mutual exclusivity between ESR1 and TP53 mutations, providing further insights and testable hypotheses of the molecular interplay between these two pivotal genes in ER+ MBC.

miR-126 Decreases Proliferation and Mammosphere Formation of MCF-7 and Predicts Prognosis of ER+ Breast Cancer

Breast cancer (BC) is a major health burden that affects over one million women each year. It is the most prevalent cancer in women and the number one cancer killer of them worldwide. Of all BC subtypes, estrogen receptor-positive (ER+) BC is the most commonly diagnosed. The objective of this study is to investigate the contribution of miR-126 in the tumorigenesis of ER+ BC. miR-126 was downregulated in ER+ BC tissues from young breast cancer patients, as shown through miRNA microarray analysis and RT-qPCR. Subsequently, the effect of the modulation of miR-126 levels on the proliferation, cell cycle progression, and spheres formation of the ER+ BC cell line, MCF-7, was assessed by MTT assay, PI analysis, and mammosphere formation assay, respectively. miR-126 overexpression significantly decreased MCF-7 proliferation and mammosphere-forming ability, but did not affect cell cycle progression. Then, in silico analysis determined SLC7A5, PLXNB2, CRK, PLK2, SPRED1, and IRS1 as potential targets of miR-126. RT-qPCR data showed that miR-126 overexpression significantly downregulated SLC7A5 and PLXNB2 mRNA levels in MCF-7. Finally, in silico survival analysis showed that high expression of miR-126 or low expression of SLC7A5 correlated with better overall survival (OS) of ER+ BC patients. Overall, our study suggests that miR-126 might play a tumor suppressor role in ER+ BC. miR-126 and SLC7A5 might also be considered potential prognostic biomarkers in ER+ BC.

Follicle-stimulating hormone-mediated decline in miR-92a-3p expression in pubertal mice Sertoli cells is crucial for germ cell differentiation and fertility

Sertoli cells (Sc) are the sole target of follicle-stimulating hormone (FSH) in the testis and attain functional maturation post-birth to significantly augment germ cell (Gc) division and differentiation at puberty. Despite having an operational microRNA (miRNA) machinery, limited information is available on miRNA-mediated regulation of Sc maturation and male fertility. We have shown before that miR-92a-3p levels decline in pubertal rat Sc. In response to FSH treatment, the expressions of FSH Receptor, Claudin11 and Klf4 were found to be elevated in pubertal rat Sc coinciding with our finding of FSH-induced decline in miR-92a-3p levels. To investigate the association of miR-92a-3p and spermatogenesis, we generated transgenic mice where such pubertal decline of miR-92a-3p was prevented by its overexpression in pubertal Sc under proximal Rhox5 promoter, which is known to be activated specifically at puberty, in Sc. Our in vivo observations provided substantial evidence that FSH-induced decline in miR-92a-3p expression during Sc maturation acts as an essential prerequisite for the pubertal onset of spermatogenesis. Elevated expression of miR-92a-3p in post-pubertal testes results into functionally compromised Sc, leading to impairment of the blood-testis barrier formation and apoptosis of pre-meiotic Gc, ultimately culminating into infertility. Collectively, our data suggest that regulation of miR-92a-3p expression is crucial for Sc-mediated induction of active spermatogenesis at puberty and regulation of male fertility.

Non-Coding RNAs in the Crosstalk between Breast Cancer Cells and Tumor-Associated Macrophages

Non-coding RNAs (ncRNAs) play a pivotal role in regulating the tumor microenvironment (TME) by controlling gene expression at multiple levels. In tumors, ncRNAs can mediate the crosstalk between cancer cells and other cells in the TME, such as immune cells, stromal cells, and endothelial cells, influencing tumor development and progression. Tumor-associated macrophages (TAMs) are among the most abundant inflammatory cells infiltrating solid cancers that promote tumorigenesis, and their infiltration correlates with a poor prognosis in many tumors. Cancer cells produce different ncRNAs that orchestrate TAM recruitment and polarization toward a tumor-promoting phenotype. Tumor-reprogrammed macrophages shape the TME by promoting angiogenesis and tissue remodeling, and suppressing the anti-tumor activity of adaptive immune cells. TAMs can also produce ncRNA molecules that boost cancer cell proliferation and direct their phenotype and metabolic changes facilitating cancer progression and metastasis. This review will focus on the crosstalk between cancer cells and TAMs mediated by microRNAs and long non-coding RNAs during breast cancer (BC) initiation and progression.

The Emerging Role of MicroRNAs in Bone Diseases and Their Therapeutic Potential

MicroRNAs (miRNAs) are a class of small (20-24 nucleotides), highly conserved, non-coding RNA molecules whose main function is the post-transcriptional regulation of gene expression through sequence-specific manners, such as mRNA degradation or translational repression. Since these key regulatory molecules are implicated in several biological processes, their altered expression affects the preservation of cellular homeostasis and leads to the development of a wide range of pathologies. Over the last few years, relevant investigations have elucidated that miRNAs participate in different stages of bone growth and development. Moreover, the abnormal expression of these RNA molecules in bone cells and tissues has been significantly associated with the progression of numerous bone diseases, including osteoporosis, osteosarcoma, osteonecrosis and bone metastasis, among others. In fact, miRNAs regulate multiple pathological mechanisms, including altering either osteogenic or osteoblast differentiation, metastasis, osteosarcoma cell proliferation, and bone loss. Therefore, in this present review, aiming to impulse the research arena of the biological implications of miRNA transcriptome in bone diseases and to explore their potentiality as a theragnostic target, we summarize the recent findings associated with the clinical significance of miRNAs in these ailments.

Multi-omics-based identification of atopic dermatitis target genes and their potential associations with metabolites and miRNAs

Atopic dermatitis (AD), or atopic eczema, is one of the most common inflammatory skin diseases with up to 10% prevalence in adults, and approximately 15-20% in children in industrialized countries. As a result, there is an unmet need for faster, safer, and effective treatments for AD. AD pathogenesis represents a complex interplay between multiple factors, such as environmental factors or stimuli, genetic factors, immune dysfunctions. However, although multi-omics label studies have been very useful in understanding the pathophysiological mechanisms of AD and its clinical manifestations, there have been very few studies that integrate different labels of omics data. Here, we attempted to integrate gene expression and metabolomics datasets from multiple different publicly available AD cohort datasets and conduct an integrated systems-level AD analysis. We used four different GEO transcriptome data sets and, by applying an elastic net machine learning algorithm, identified robust hub genes that can be used as signatures, for example, H2AFX, MCM7, ESR1 and SF3A2. Moreover, we investigated potential associations of those genes by applying a pathway-based approach over metabolomics and miRNA datasets. Our results revealed potential novel associations between fatty acids and peroxisomal lipid metabolism pathways, as well as with several microRNAs.

Epigenetic Reprogramming and Landscape of Transcriptomic Interactions: Impending Therapeutic Interference of Triple-Negative Breast Cancer in Molecular Medicine

The mechanisms governing the development and progression of cancers are believed to be the consequence of hereditary deformities and epigenetic modifications. Accordingly, epigenetics has become an incredible and progressively explored field of research to discover better prevention and therapy for neoplasia, especially triple-negative breast cancer (TNBC). It represents 15-20% of all invasive breast cancers and will, in general, have bellicose histological highlights and poor clinical outcomes. In the early phases of triple-negative breast carcinogenesis, epigenetic deregulation modifies chromatin structure and influences the plasticity of cells. It up-keeps the oncogenic reprogramming of malignant progenitor cells with the acquisition of unrestrained selfrenewal capacities. Genomic impulsiveness in TNBC prompts mutations, copy number variations, as well as genetic rearrangements, while epigenetic remodeling includes an amendment by DNA methylation, histone modification, and noncoding RNAs of gene expression profiles. It is currently evident that epigenetic mechanisms assume a significant part in the pathogenesis, maintenance, and therapeutic resistance of TNBC. Although TNBC is a heterogeneous malaise that is perplexing to describe and treat, the ongoing explosion of genetic and epigenetic research will help to expand these endeavors. Latest developments in transcriptome analysis have reformed our understanding of human diseases, including TNBC at the molecular medicine level. It is appealing to envision transcriptomic biomarkers to comprehend tumor behavior more readily regarding its cellular microenvironment. Understanding these essential biomarkers and molecular changes will propel our capability to treat TNBC adequately. This review will depict the different aspects of epigenetics and the landscape of transcriptomics in triple-negative breast carcinogenesis and their impending application for diagnosis, prognosis, and treatment decision with the view of molecular medicine.

Endocrine resistance and epigenetic reprogramming in estrogen receptor positive breast cancer

Despite the enormous advances during the last three decades, breast cancer continues to be the most frequent type of cancer as well as one of the most frequent cancer-related causes of death in women. Therapeutic management of patients with hormone receptor-positive breast cancer becomes very often a challenge, since de novo or acquired resistance deprives a significant percentage of the patients from the clinical benefit of the well-tolerated hormone therapy. Several molecular mechanisms are implicated in resistance to endocrine therapy, including changes in hormone receptor signaling, activation of parallel signaling pathways, modifications of cell cycle regulators, activation of different transcription factors as well as changes in stem cells activity. In addition, a growing number of studies supports the pivotal role of epigenetic changes not only in the initiation and progression of breast cancer, but also in resistance to endocrine therapy. These changes refer to DNA methylation, histone post-translational modifications as well as to ncRNAs alterations. In this review, we provide an overview of epigenetic mechanisms underlying the endocrine resistance focusing exclusively on breast cancer patients.

CBP-JMF: An Improved Joint Matrix Tri-Factorization Method for Characterizing Complex Biological Processes of Diseases

Multi-omics molecules regulate complex biological processes (CBPs), which reflect the activities of various molecules in living organisms. Meanwhile, the applications to represent disease subtypes and cell types have created an urgent need for sample grouping and associated CBP-inferring tools. In this paper, we present CBP-JMF, a practical tool primarily for discovering CBPs, which underlie sample groups as disease subtypes in applications. Differently from existing methods, CBP-JMF is based on a joint non-negative matrix tri-factorization framework and is implemented in Python. As a pragmatic application, we apply CBP-JMF to identify CBPs for four subtypes of breast cancer. The result shows significant overlapping between genes extracted from CBPs and known subtype pathways. We verify the effectiveness of our tool in detecting CBPs that interpret subtypes of disease.

Differential methylation and expression patterns of microRNAs in relation to breast cancer subtypes among American women of African and European ancestry

Aggressive high-grade, estrogen receptor negative (ER-) breast cancer is more common among American women of African ancestry (AA) than those of European ancestry (EA). Epigenetic mechanisms, particularly DNA methylation and altered microRNA (miRNA) expression, may contribute to racial differences in breast cancer. However, few studies have specifically characterized genome-wide DNA methylation-based modifications at the miRNA level in relation to ER+ and ER- subtype, and their functional role in the regulation of miRNA expression, especially among high risk AA women. In this study, we evaluated DNA methylation patterns of miRNA encoding genes and their effect on expression in breast tumors from both AA and EA women. The genome-wide methylation screen identified a total of 7,191 unique CpGs mapped to 1,292 miRNA genes, corresponding to 2,035 unique mature miRNAs. We identified differentially methylated loci (DMLs: (|delta β|)>0.10, FDR<0.05) between ER- and ER+ tumor subtypes, including 290 DMLs shared in both races, 317 and 136 were specific to AA and EA women, respectively. Integrated analysis identified certain DMLs whose methylation levels were significantly correlated with the expression of relevant miRNAs, such as multiple CpGs within miR-190b and miR-135b highly negatively correlated with their expression. These results were then validated in the TCGA dataset. Target prediction and pathway analysis showed that these DNA methylation-dysregulated miRNAs are involved in multiple cancer-related pathways, including cell cycle G1-S growth factor regulation, cytoskeleton remodeling, angiogenesis, EMT, and ESR1-mediated signaling pathways. In summary, our results suggest that DNA methylation changes within miRNA genes are associated with altered miRNA expression, which may contribute to the network of subtype- and race-related tumor biological differences in breast cancer. These findings support the involvement of epigenetic regulation of miRNA expression and provide insights into the relations of clinical-relevant miRNAs to their target genes, which may serve as potential preventative and therapeutic targets.

Lifetime Impact of Cow's Milk on Overactivation of mTORC1: From Fetal to Childhood Overgrowth, Acne, Diabetes, Cancers, and Neurodegeneration

The consumption of cow's milk is a part of the basic nutritional habits of Western industrialized countries. Recent epidemiological studies associate the intake of cow's milk with an increased risk of diseases, which are associated with overactivated mechanistic target of rapamycin complex 1 (mTORC1) signaling. This review presents current epidemiological and translational evidence linking milk consumption to the regulation of mTORC1, the master-switch for eukaryotic cell growth. Epidemiological studies confirm a correlation between cow's milk consumption and birthweight, body mass index, onset of menarche, linear growth during childhood, acne vulgaris, type 2 diabetes mellitus, prostate cancer, breast cancer, hepatocellular carcinoma, diffuse large B-cell lymphoma, neurodegenerative diseases, and all-cause mortality. Thus, long-term persistent consumption of cow's milk increases the risk of mTORC1-driven diseases of civilization. Milk is a highly conserved, lactation genome-controlled signaling system that functions as a maternal-neonatal relay for optimized species-specific activation of mTORC1, the nexus for regulation of eukaryotic cell growth, and control of autophagy. A deeper understanding of milk´s impact on mTORC1 signaling is of critical importance for the prevention of common diseases of civilization.

Estradiol-Responsive miR-365a-3p Interacts with Tissue Factor 3'UTR to Modulate Tissue Factor-Initiated Thrombin Generation

BACKGROUND

 High estradiol (E₂) levels are linked to an increased risk of venous thromboembolism; however, the underlying molecular mechanism(s) remain poorly understood. We previously identified an E₂-responsive microRNA (miR), miR-494-3p, that downregulates protein S expression, and posited additional coagulation factors, such as tissue factor, may be regulated in a similar manner via miRs.

OBJECTIVES

 To evaluate the coagulation capacity of cohorts with high physiological E₂, and to further characterize novel E₂-responsive miR and miR regulation on tissue factor in E₂-related hypercoagulability.

METHODS

 Ceveron Alpha thrombin generation assay (TGA) was used to assess plasma coagulation profile of three cohorts. The effect of physiological levels of E₂, 10 nM, on miR expression in HuH-7 cells was compared using NanoString nCounter and validated with independent assays. The effect of tissue factor-interacting miR was confirmed by dual-luciferase reporter assays, immunoblotting, flow cytometry, biochemistry assays, and TGA.

RESULTS

 Plasma samples from pregnant women and women on the contraceptive pill were confirmed to be hypercoagulable (compared with sex-matched controls). At equivalent and high physiological levels of E₂, miR-365a-3p displayed concordant E₂ downregulation in two independent miR quantification platforms, and tissue factor protein was upregulated by E₂ treatment. Direct interaction between miR-365a-3p and F3-3'UTR was confirmed and overexpression of miR-365a-3p led to a decrease of (1) tissue factor mRNA transcripts, (2) protein levels, (3) activity, and (4) tissue factor-initiated thrombin generation.

CONCLUSION

 miR-365a-3p is a novel tissue factor regulator. High E₂ concentrations induce a hypercoagulable state via a miR network specific for coagulation factors.

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 and SARS-Related Coronaviruses

The emergence of SARS-CoV-2 in 2019 has caused a major health and economic crisis around the globe. Gaining knowledge about its attributes and interactions with human host cells is crucial. Non-coding RNAs (ncRNAs) are involved in the host cells' innate antiviral immune response. In RNA interference, microRNAs (miRNAs) may bind to complementary sequences of the viral RNA strand, forming an miRNA-induced silencing complex, which destroys the viral RNA, thereby inhibiting viral protein expression. There are several targets for human miRNAs on SARS-CoV-2's RNA, most of which are in the 5' and 3' untranslated regions. Mutations of the viral genome causing the creation or loss of miRNA binding sites may have crucial effects on SARS-CoV-2 pathogenicity. In addition to mediating immunity, the ncRNA landscape of host cells further influences their susceptibility to virus infection, as certain miRNAs are essential in the regulation of cellular receptors that are necessary for virus invasion. Conversely, virus infection also changes the host ncRNA expression patterns, possibly augmenting conditions for viral replication and dissemination. Hence, ncRNAs typically upregulated in SARS-CoV-2 infection could be useful biomarkers for disease progression and severity. Understanding these mechanisms could provide further insight into the pathogenesis and possible treatment options against COVID-19.

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.

Approaching Sex Differences in Cardiovascular Non-Coding RNA Research

Cardiovascular disease (CVD) is the biggest cause of sickness and mortality worldwide in both males and females. Clinical statistics demonstrate clear sex differences in risk, prevalence, mortality rates, and response to treatment for different entities of CVD. The reason for this remains poorly understood. Non-coding RNAs (ncRNAs) are emerging as key mediators and biomarkers of CVD. Similarly, current knowledge on differential regulation, expression, and pathology-associated function of ncRNAs between sexes is minimal. Here, we provide a state-of-the-art overview of what is known on sex differences in ncRNA research in CVD as well as discussing the contributing biological factors to this sex dimorphism including genetic and epigenetic factors and sex hormone regulation of transcription. We then focus on the experimental models of CVD and their use in translational ncRNA research in the cardiovascular field. In particular, we want to highlight the importance of considering sex of the cellular and pre-clinical models in clinical studies in ncRNA research and to carefully consider the appropriate experimental models most applicable to human patient populations. Moreover, we aim to identify sex-specific targets for treatment and diagnosis for the biggest socioeconomic health problem globally.

The Effect of (E)-1-(4'-aminophenyl)-3-phenylprop-2-en-1-one on MicroRNA-18a, Dicer1, and MMP-9 Expressions against DMBA-Induced Breast Cancer

BACKGROUND

Most of breast cancer patients are estrogen receptor alpha-positive and have high resistance and side effect of chemotherapeutic drug. Therefore, discovering an effective anticancer agent is needed. This research explored the effect of (E)-1-(4'-aminophenyl)-3-phenylprop-2-en-1-one (APE) on miR-18a, Dicer1, and MMP-9 expressions.

METHODS

Twenty four female Sprague-Dawley rats were invetigated in this study. The rats were divided into 6 groups of 4. G1 was considered as normal rat. G2, G3, T1, T2, and T3 were given DMBA 20 mg/kgBW twice a week for 5 weeks to induce mammary cancer. After being affiliated with cancer, G2 was given vehicle and G3 was treated with tamoxifen. T1, T2, and T3 were treated with APE intraperitoneally everyday for 21 days at doses of 5, 15, and 45 mg/kgBW/day, respectively. Blood plasma was collected to measure miR-18a expression using qRT-PCR. Mammary tissues were also collected to determine Dicer1 and MMP-9 expressions by using  immunohistochemistry.

RESULTS

The results showed significant down-regulation of miR-18a relative expression and up-regulation of Dicer1 expression in G3 and T1 compared to G2 (P<0.05). MMP-9 expression has significant decrease in T1 compared to G2 (P<0.05).

CONCLUSION

APE can decrease miR-18a and MMP-9 expressions and increase Dicer1 expression in rat mammary cancer. Therefore, this compound could be a candidate of novel anticancer.

Serum microRNAs as novel biomarkers for osteoporotic vertebral fractures

CONTEXT

Vertebral fractures are the hallmark of osteoporosis. MicroRNAs (miRNAs) are a prominent class of gene regulators likely to affect bone homeostasis, including bone remodelling and fracture healing by altering gene expression in bone cells.

OBJECTIVE

This study sought to compare the levels of circulating miRNAs in older women with osteoporotic vertebral fractures, and/or low BMD and healthy controls, and to correlate miRNAs expression levels with BTMs.

DESIGN

A single-site, case-control, observational, cross-sectional study at a university hospital.

PARTICIPANTS

Altogether, 126 postmenopausal women belonging to four different groups were included: healthy (n=42), low BMD and no vertebral fractures (n=39), vertebral fractures and low BMD without a treatment (n=26), or receiving a treatment for osteoporosis (n=19).

MAIN OUTCOME MEASURE

Serum samples from all participants were analyzed for 21 microRNA bone biomarkers.

RESULTS

We identified 7 significantly (p<0.05) up-regulated miRNAs (miR-375, miR-532-3p, miR-19b-3p, miR-152-3p, miR-23a-3p, miR-335-5p, miR-21-5p) in patients with vertebral fractures and low BMD compared to low BMD and healthy individuals, regardless of osteoporosis treatment. No significant differences existed between low BMD and healthy controls. We observed 24 significant correlations (P<0.05) between miRNAs and BTMs (CTX, PINP, OC and bone ALP).

CONCLUSIONS

Specific circulating miRNAs reflect the presence of osteoporotic vertebral fractures in postmenopausal women. They are unlikely to reflect low BMD, and more likely changes in bone quality or fracture healing. The effects of osteoporosis treatment on the selected miRNAs appear to be weaker than effects caused by vertebral fractures. The correlation between miRNAs and BTMs suggest that miRNAs may be involved in bone turnover or fracture healing.

Comparing MicroRNA Profilings of Purified HER-2-Negative and HER-2-Positive Cells Validates miR-362-5p/Sema3A as Characteristic Molecular Change in Triple-Negative Breast Cancers

Background

HER-2 is a key molecule serving as the therapeutic target, prognostic biomarker, and classification marker in breast cancer. Accurate microRNA profilings had not been conducted in purified tumor cells of HER-2-negative and HER-2-positive tissue specimens obtained from breast cancer patients.

Methods

(i) Differential expression microRNA discovery using laser capture microdissection- (LCM-) assisted specimen preparation and microRNA array chips on HER-2 overexpressing and triple-negative breast carcinoma (TNBC) subtype tissues, (ii) differential expression microRNA validation by quantitative real-time PCR, and (iii) independent validation on tissue microarray.

Results

Five microRNAs (miR-20a-5p, miR-221-3p, miR-362-5p, miR-502-3p, and miR-222-3p) were screened and validated as upregulated microRNAs in TNBC cells comparing to HER-2 overexpressing cells using a microRNA array (5 cases in each group) and quantitative real-time PCR (20 cases in each group). The expression difference of miR-362-5p had the most significant statistical significance (p = 0.0016) among the five microRNAs. The expression of miR-362-5p and its target gene Sema3A was further analyzed using in situ hybridization (ISH) and immunohistochemistry on standard tissue sections (n = 150). 70.8% of HER-2-negative cells showed moderate expression of miR-362-5p whereas 20.4% HER-2-negative cells correlated with strong expression of miR-362-5p (p < 0.0001). The proportion of patients with moderate/strong miR-362-5p expression in luminal, HER-2 overexpressing, and TNBC subtypes were 53.2%, 22.2%, and 74.3%, respectively (p = 0.0002). High miR-362-5p expressers had shorter overall survival in the univariate analysis (p = 0.046). There was a significant negative correlation between miR-362-5p and Sema3A expression (p < 0.0001). The patients with negative/weak Sema3A protein expression had poorer prognosis than those with moderate (HR: 3.723, p = 0.021) or strong (HR: 3.966, p = 0.013) Sema3A protein expression in the multivariate analysis.

Conclusions

miR-362-5p/Sema3A might provide a promising therapeutic pathway and represents a candidate therapeutic target of the TNBC subtype.

MiR-128-3p suppresses breast cancer cellular progression via targeting LIMK1

Breast cancer is the most common malignancy in women all over the world. MiRNAs are a type of small noncoding RNA that can regulate various cellular processes via binding different target genes in cancer cells. In this study, we found that miR-128-3p could suppress cellular proliferation and motility abilities of breast cancer. In addition, we found that overexpression of miR-128-3p arrested breast cancer cells in G0/G1 phase by affecting expression of CDK4/CDK6/Cyclin D1 and CDK2/Cyclin E1. Furthermore, we confirmed that LIM domain kinase 1 (LIMK1) is a direct target gene of miR-128-3p and that overexpression of miR-128-3p could suppress the expression levels of LIMK1 and Cofilin 1, which is downstream of LIMK1. TCGA clinical database showed that miR-128-3p was highly expressed in breast cancer patients and that high expression of miR-128-3p indicates a better prognosis of breast cancer. Our findings demonstrated that miR-128-3p could regulate cellular progression of breast cancer via regulating the LIMK1/CFL1 signaling pathway, and this new avenue could broaden existing versions of molecular mechanisms in breast cancer and perhaps represent potential novel direction of breast cancer treatment in the future.

Shikimic acid promotes estrogen receptor(ER)-positive breast cancer cells proliferation via activation of NF-κB signaling

Shikimic acid (SA), a widely-known hydroaromatic compound enriched in Bracken fern and Illicium verum (also known as Chinese star anise), increases the risk of gastric and esophageal carcinoma, nevertheless, the influence of SA on breast cancer remains indistinct. Herein we found that, with models in vitro, SA significantly promoted estrogen receptor(ER) positive cells proliferation and NF-κB activation was involved in it. Moreover, our data showed that IκBα, a critically endogenous inhibitor of NF-κB, was repressed. Subsequently, we found increase of miR-300 by SA treatment sand miR-300 could target IκBα mRNA. Additionally, inhibition of miR-300 abrogated the repression of IκBα by SA. As a result, miR-300 was also involved in NF-κB activation and breast cancer cells proliferation promotion due to SA exposure. Taken together, with ER-positive breast cancer cell models in vitro, MCF-7 and T47D, our results implied that SA promoted breast cancer cells proliferation via a miR-300-induced NF-κB dependent pathway controlling cell cycle proteins.

Exosomes of pasteurized milk: potential pathogens of Western diseases

Milk consumption is a hallmark of western diet. According to common believes, milk consumption has beneficial effects for human health. Pasteurization of cow's milk protects thermolabile vitamins and other organic compounds including bioactive and bioavailable exosomes and extracellular vesicles in the range of 40-120 nm, which are pivotal mediators of cell communication via systemic transfer of specific micro-ribonucleic acids, mRNAs and regulatory proteins such as transforming growth factor-β. There is compelling evidence that human and bovine milk exosomes play a crucial role for adequate metabolic and immunological programming of the newborn infant at the beginning of extrauterine life. Milk exosomes assist in executing an anabolic, growth-promoting and immunological program confined to the postnatal period in all mammals. However, epidemiological and translational evidence presented in this review indicates that continuous exposure of humans to exosomes of pasteurized milk may confer a substantial risk for the development of chronic diseases of civilization including obesity, type 2 diabetes mellitus, osteoporosis, common cancers (prostate, breast, liver, B-cells) as well as Parkinson's disease. Exosomes of pasteurized milk may represent new pathogens that should not reach the human food chain.

The clinicopathological significance of decreased miR-125b-5p in hepatocellular carcinoma: evidence based on RT-qPCR, microRNA-microarray, and microRNA-sequencing

The aim of the study was to comprehensively evaluate the clinical value of miR-125b-5p in hepatocellular carcinoma (HCC) and its potential molecular mechanisms. MiR-125b-5p expression was remarkably lower as examined by real-time reverse transcription quantitative polymerase chain reaction (RT-qPCR) in 95 paired HCC and nonmalignant liver tissues in house (P<0.001), which was in accord with the results from miRNA-sequencing data with 371 cases of HCC. miRNA-chips from Gene Expression Omnibus (GEO) and ArrayExpress were screened. Among the seven included miRNA-chips, the relative expression of miR-125b-5p expression levels showed decreasing trends in HCC tissue samples compared with non-cancerous liver tissue samples. Altogether, A total of 655 cases of HCC tissues and 334 non-HCC liver tissues were included in the final meta-analysis. We observed that the expression of miR-125b-5p indeed decreased markedly in HCC tissues compared with the non-HCC tissues (SMD: -1.414, 95% CI: -1.894 to -0.935, P<0.001). The area under the SROC curve of lower expression of miR-125b-5p was 0.91 (95% CI: 0.89 to 0.94). A Kaplan-Meier survival analysis indicated that the lower expression or the absence of miR-125b-5p may be a risk factor for the poor outcome of HCC patients. Furthermore, the potential target genes of miR-125b-5p from 11 miRNA target prediction databases were intersected with 1,486 differentially expressed genes (DEGs) as calculated by RNA-sequencing data. Finally, a total of 330 GEGs were collected and enriched in the pathways of lysosome, focal adhesion, and pathways in cancer. In conclusion, this study utilizes a variety of research methods to confirm the lower level of miR-125b-5p in HCC tissues. This lower expression level of miR-125b-5p is closely related to increased disease progression in HCC patients.

Plasma miR-21, miR-155, miR-10b, and Let-7a as the potential biomarkers for the monitoring of breast cancer patients

There is a pressing need for further studies to categorize and validate circulating microRNAs (miRs) in breast cancer patients that can be one of the novel strategies for cancer screening and monitoring. The present study is aimed to investigate the expression of the circulating candidate microRNAs after the operation, chemotherapy, and radiotherapy in the non-metastatic breast cancer patients. Tumor tissue and plasma samples were collected from the 30 patients with recently diagnosed Luminal A breast cancer. Control plasma samples were collected from the 10 healthy subjects. A panel of four miRs including miR-21, miR-55, miR-10b, and Let-7a were selected and their expression levels were measured before and after the operation, chemotherapy, and radiotherapy by using Real-Time PCR technique. The plasma expression of the miR-21, miR-155, and miR-10b was significantly increased and the Let-7a plasma expression decreased in the breast cancer patients compromised to the control ones. There was a similar expression pattern of the miRs between the tissue and plasma samples. The plasma levels of the miR-21, miR-155, and miR-10b were significantly down-regulated and the Let-7a plasma level was up-regulated after the operation, chemotherapy, and radiotherapy compromised to the pre-treatment. There was a significant difference in the miR-155 plasma level after the operation, chemotherapy, and radiotherapy compromised with each other. Moreover, there was no significant difference between the plasma levels of the miRs after the radiotherapy compromised to the control cases. The operation, chemotherapy, and radiotherapy led to a more reduction in the oncomiRs and an increase in the tumor suppressor-miRs. It seems that monitoring miRs during treatment might be considered as a respectable diagnostic tool for monitoring of breast cancer patients.