miR-148a Suppresses estrogen-induced viability and migration of breast cancer cells via inhibition of estrogen receptor α expression

Evaluation of Serum MicroRNAs (miR-9-5p, miR-17-5p, and miR-148a-3p) as Potential Biomarkers of Breast Cancer

Background

MicroRNAs (miRNAs) play important roles in the initiation and progression of cancers. The purpose of the present study was to evaluate the use of serum miRNA biomarkers in the early diagnosis of breast cancer.

Methods

The expression levels of miR-9-5p, miR-17-5p, and miR-148a-3p were analyzed by quantitative reverse transcription-polymerase chain reaction in 49 patients with newly diagnosed breast cancer and 49 healthy controls. The associations between miR-9-5p, miR-17-5p, and miR-148a-3p levels and clinicopathological parameters were also analyzed. Regression analysis and sensitivity and specificity analyses were used to determine the diagnostic efficacy of the miRNAs.

Results

Serum levels of miR-9-5p and miR-148a-3p were significantly higher in breast cancer patients than in healthy controls (both P < 0.05), but miR-17-5p levels were not different between the two groups (P = 0.996). Serum miR-9-5p levels were markedly higher in patients with human epidermal growth factor receptor 2- (HER2-) positive breast cancer than in those with HER2-negative breast cancer (P = 0.049). Serum levels of miR-9-5p and miR-148a-3p were positively correlated with the presence of breast cancer, and both miRNAs had high sensitivity and specificity for the diagnosis of breast cancer.

Conclusions

These findings provide evidence that serum miR-9-5p and miR-148a-3p levels may be used as noninvasive biological markers for the clinical diagnosis of breast cancer.

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.

Plasma-based microRNA signatures in early diagnosis of breast cancer

Background

MicroRNAs (miRNAs) play an important role in the development and progression of breast cancer (BC). The purpose of the present study was to identify plasma miRNAs enabling early diagnosis of BC.

Materials and Methods

Expression levels of seven plasma miRNAs (miR‐23a‐3p, miR‐29b‐2‐5p, miR‐130a‐5p, miR‐144‐3p, miR‐148a‐3p, miR‐152‐3p, and miR‐182‐5p) in 106 patients with newly diagnosed BC and 96 healthy participants were analyzed by qRT‐PCR. We also evaluated the relationship between the expression levels of these miRNAs and clinicopathological features of patients with BC.

Results

Compared with healthy controls, we found that miR‐23a‐3p (p = .025), miR‐130a‐5p (p = .006), miR‐144‐3p (p = .040), miR‐148a‐3p (p = .023), and miR‐152‐3p (p = .019) were downregulated in the plasma of patients with BC. MiR‐130a‐5p, miR‐144‐3p, and miR‐152‐3p were downexpressed in BC tissues as well as plasma. The expression of the miR‐23a‐3p, miR‐144‐3p, and miR‐152‐3p was related to ER positive and PR positive. Besides, miR‐23a‐3p, miR‐144‐3p, and miR‐152‐3p did show the significant difference in the staging compromised to the control, especially in stage I‐II. Moreover, we also found that miR‐144‐3p and miR‐148a‐3p were associated with lymph node invasion.

Conclusions

The expression levels of the miR‐23a‐3p, miR‐130a‐5p, miR‐144‐3p, miR‐148a‐3p, and miR‐152‐3p were lower in patients with BC compared to healthy controls and were associated with ex hormone receptor, clinical stage, and lymph node metastasis, indicating the diagnostic potential of these miRNAs in BC.

Overexpression of miR-148a inhibits viability and invasion of ovarian cancer OVCAR3 cells by targeting FOXO3

Decreased expression of microRNA (miR)-148a is associated with poor prognosis in ovarian cancer. The aim of the present study was to investigate the impact of miR-148a on tumor cell viability and invasion via targeting forkhead box protein O3 (FOXO3). Expression of miR-148a was detected in paired tumor and adjacent normal tissues. OVCAR3 cells were transfected with miR-148a mimic and inhibitor. Cell viability, apoptosis and invasion were determined. A luciferase reporter assay was used to study the association between miR-148a and FOXO3. In addition, the influence of miR-148a on tumor cell growth was investigated by performing xenograft assays in nude mice. RT-qPCR showed that miR-148a was downregulated in ovarian cancer tissues. Overexpression of miR-148a in OVCAR3 cells inhibited cell viability, suppressed invasion and promoted cellular apoptosis. The dual-luciferase assay indicated that miR-148a directly regulated the expression of FOXO3, a transcription factor of caspase-3. Western blotting confirmed that the expression of caspase-3 was regulated by the modulation of miR-148a expression. In vivo assays revealed that miR-148a overexpression inhibited the growth of OVCAR3 ×enograft tumors in nude mice. miR-148a is a tumor suppressor in ovarian cancer OVCAR3 cells and in nude mice. The suppressive effect is due to inhibiting cell viability and invasion as well as promoting apoptosis. These results may provide theoretical basis for targeting miR-148a in the treatment of ovarian cancer.

G protein-coupled estrogen receptor mediates anti-inflammatory action in Crohn's disease

Estrogens exert immunomodulatory action in many autoimmune diseases. Accumulating evidence highlights the meaningful impact of estrogen receptors in physiology and pathophysiology of the colon. However, the significance of G protein-coupled estrogen receptor (GPER) on Crohn's disease (CD), one of the inflammatory bowel disease (IBD) types, is still elusive. Our study revealed GPER overexpression at the mRNA and protein levels in patients with CD. To evaluate the effects of GPER activation/inhibition on colitis development, a murine 2, 4, 6-trinitrobenzene sulfonic acid (TNBS)-induced model of CD was used. We showed that activation of GPER reduces mortality, improves macroscopic and microscopic scores and lowers C-reactive protein (CRP) level. The impact of estrogen signaling on the suppression of the intestinal inflammation was proved by immunohistochemistry. It was demonstrated that GPER activation is accompanied by modulation of extracellular-signal regulated kinase (ERK) signaling pathway and expression level of genes involved in signal transmission and immune response as well as the expression of some microRNAs (miR-145, miR-148-5p and miR-592). Our study revealed that the membrane-bound estrogen receptor GPER mediates anti-inflammatory action and seems to be a potent therapeutic target in maintaining remission in CD.

The transcription factor SMAD4 and miR-10b contribute to E2 release and cell apoptosis in ovarian granulosa cells by targeting CYP19A1

The cytochrome P450 family 19 subfamily A member 1 (CYP19A1) gene, encodes aromatase, a key enzyme in estradiol (E2) synthesis, and is down-regulated during porcine follicular atresia. However, its role in and the mechanism of transcriptional repression in follicular atresia is largely unknown. In the present study, we show that the CYP19A1 gene stimulates E2 release and inhibits cell apoptosis in porcine granulosa cells (GCs). SMAD4, an anti-apoptotic moderator, was identified as a transcription factor of the porcine CYP19A1 gene and enhanced the expression and function of CYP19A1 in porcine GCs through direct binding to a SMAD4-binding element (SBE) within the promoter region of CYP19A1 gene. Moreover, we found that miR-10b, a pro-apoptotic factor, directly interacted with 3'-UTR of the porcine CYP19A1 mRNA, inhibiting its expression and function in porcine GCs. Collectively, we demonstrated that CYP19A1 is an inhibitor of follicular atresia and is regulated by both SMAD4 and miR-10b. These findings provide further insight into the mechanisms of CYP19A1 in steroid hormone synthesis and GC apoptosis and provide molecular targets for exploring methods of treatment for steroid-dependent reproductive disorders.

Sex differences in miRNA as therapies for ischemic stroke

MicroRNAs, a subset of non-coding RNAs, are present in virtually all tissues including body fluids and are global regulators of the transcriptome. In view of the expanding number of microRNAs and the large number of gene targets that each microRNA can potentially regulate, they have been compared to hormones in the scope of their effects. MicroRNA have been implicated as biomarkers for several diseases including stroke, as well as chronic conditions that are associated with stroke. Recent research has focused on manipulating miRNA to improve stroke outcomes. Although several miRNAs have been shown to have neuroprotective properties, the overwhelming majority of these studies have employed only male animals. This review will focus on two miRNAs, Let7f and mir363-3p, whose effectiveness as a stroke neuroprotectant is sex-specific.

Estrogen signaling deregulation related with local immune response modulation in irritable bowel syndrome

The etiology and pathogenesis underlying irritable bowel syndrome (IBS), a common gastrointestinal disorder are still unclear. Cumulating data suggest dysregulation of inflammatory and immune response pathways and changes of epithelial barrier function. The role of estrogens albeit varied, in responses of immune system is well documented. The aim of this study was to investigate estrogen receptors engagment in IBS subtypes, i.e. constipation predominant (IBS-C) and diarrhea predominant (IBS-D). Furthermore, we analyzed whether estrogen signaling is accompanied by alteration in expression of pro- and anti-inflammatory cytokines and microRNAs that can regulate among others genes involved in immune responses. It was found that estrogen receptor α (ERα) and G protein-coupled estrogen receptor (GPER) expression is up-regulated in IBS while estrogen receptor β (ERβ) appears to be down-regulated at mRNA but up-regulated at the protein level. When gender and female age were included statistically significant overexpression of ERα in IBS-D women under the age of 50, while of GPER in IBS-D men was stated. In all studied IBS samples disturbances in expression of cytokines IL-6, IL-10 and TNF-α as well as miR-145, miR-148-5p and miR-592 were observed. This research reveals the association of estrogen receptors with IBS. Simultaneous alterations of studied immunomodulatory cytokines and microRNAs suggest that in IBS dysregulation of local immune response may involve estrogen-dependent way.

MicroRNA‑148a inhibition protects against ovariectomy‑induced osteoporosis through PI3K/AKT signaling by estrogen receptor α

The present study aimed to investigate the effect of microRNA‑148a downregulation on osteoporosis by using an ovariectomized rat model. Reverse transcription‑quantitative polymerase chain reaction was used to analyze microRNA‑148a expression levels, MTT and flow cytometry assays were used to examine cytotoxicity and apoptosis, respectively. The gap‑associated proteins were quantified using western blotting. The expression of microRNA‑148a was significantly increased in osteoporosis rat following ovariectomy. Overexpression of microRNA‑148a significantly promoted apoptosis and inhibited cell growth, whereas downregulation of microRNA‑148a significantly reduced apoptosis and increased cell growth. Overexpression of microRNA‑148a significantly reduced estrogen receptor a (ERα) protein expression and suppressed phosphoinositide‑3‑kinase regulatory subunit 1 (PI3K) and phosphorylated‑protein kinase B (AKT) protein expression in osteoblasts in vitro. The inhibition of ERα increased the microRNA‑148a effect on apoptosis in osteoblasts in vitro. Subsequently, LY294002, an PI3K inhibitor, significantly increased the effect of microRNA‑148a on apoptosis in osteoblasts in vitro. The findings of the present study revealed that anti‑microRNA‑148a protected cells against ovariectomy‑induced osteoporosis through ERα by PI3K/AKT signaling.