Expression profiling of cancerous and normal breast tissues identifies microRNAs that are differentially expressed in serum from patients with (metastatic) breast cancer and healthy volunteers

Blood-based microRNA profiling unveils complex molecular dynamics in breast cancer

BACKGROUND

Breast cancer, a genetically intricate disease with diverse subtypes, exhibits heightened incidence globally. In this study, we aimed to investigate blood-based microRNAs (miRNAs) as potential biomarkers for breast cancer. The primary objectives were to explore the role of miRNAs in cancer-related processes, assess their differential expression between breast cancer patients and healthy individuals, and contribute to a deeper understanding of the molecular underpinnings of breast cancer.

METHODS

MiRNA extraction was performed on 40 breast cancer patients and adjacent normal tissues using a commercial RNA isolation kit. Total RNA quantification and quality assessment were conducted with advanced technologies. MiRNA profiling involved reverse transcription, labeling, and hybridization on Agilent human miRNA arrays (V2). Bioinformatics analysis utilized the DIANA system for target gene prediction and the DIANA-mirPath tool for pathway enrichment analysis. Selected miRNAs underwent validation through quantitative real-time PCR.

RESULTS

Principal component analysis revealed overlapping miRNA expression patterns in primary and malignant breast tumors, underscoring the genetic complexity involved. Statistical analysis identified 54 downregulated miRNAs in malignant tumors and 38 in primary tumors compared to controls. Bioinformatics analysis implicated several pathways, including Wnt, TGF-b, ErbB, and MAPK signaling. Validation through qRT-PCR confirmed altered expression of hsa-miR-130a, hsa-miR-21, hsa-miR-223, and hsa-let-7c key miRNAs, highlighting their significance in breast cancer. The results from microarray were further validated by qPCR and the expression of which are downregulated in breast cancer was detected.

CONCLUSION

This study provides significant insights into distinct miRNA expression patterns in normal and malignant breast tissues. The overlapping miRNA profiles in primary and malignant tumors underscore the complexity of genetic regulation in breast cancer. The identification of deregulated miRNAs and affected pathways contributes to our understanding of breast cancer pathogenesis. The validated miRNAs hold potential as diagnostic and prognostic markers, offering avenues for further clinical exploration in breast cancer research.

Serum miR-215-5p, miR-192-5p and miR-378a-5p as novel diagnostic biomarkers for periampullary adenocarcinoma

OBJECTIVE

MicroRNAs (miRNAs) are present in human serum in a stable form. Circulating miRNAs are increasingly recognized as promising biomarkers for early cancer detection. The aim of this study was to identify serum miRNAs as biomarkers for periampullary adenocarcinoma (PAC).

PATIENTS AND METHODS

68 patients with PAC and 50 healthy controls (HCs) subjects were recruited in this study. The expression levels of 11 selected miRNAs were determined in serum samples using the SYBR-green quantitative reverse transcription polymerase chain reaction (qRT-PCR) method. Receiver operating characteristic (ROC) analysis was used to evaluate the diagnostic potential of serum miRNAs.

RESULTS

The expression levels of three miRNAs (miR-215-5p, miR-192-5p, and miR-378a-5p) were significantly upregulated in the serum samples derived from the PAC patients compared with those from the HC (p < 0.001). The ROC analysis showed that all three significantly altered miRNAs (miR-215-5p, miR-192-5p, and miR-378a-5p) could potentially discriminate patients with PAC from HC with AUC value of 0.771 (95% CI: 0.684-0.843), 0.877 (95% CI: 0.799-0.927) and 0.768 (95% CI: 0.674-0.853) respectively. Further comparisons showed that these three serum miRNAs (miR-215-5p, miR-192-5p, and miR-378a-5p) can strongly discriminate early-stage PAC patients from HC with an AUC value of 0.802 (95% CI: 0.719-0.886), 0.870 (95% CI: 0.793-0.974) and 0.793 (95% CI: 0.706-0.880) respectively, may aid in early detection of PAC.

CONCLUSIONS

Taken together, our findings demonstrated that these three serum miRNAs (miR-215-5p, miR-192-5p, and miR-378a-5p) may serve as noninvasive biomarkers for the early detection of PAC.

Exploring the role of estrogen and progestins in breast cancer: A genomic approach to diagnosis

Breast cancer (BC) is the most common cancer among women and a major cause of death from cancer. The role of estrogen and progestins, including synthetic hormones like R5020, in the development of BC has been highlighted in numerous studies. In our study, we employed machine learning and advanced bioinformatics to identify genes that could serve as diagnostic markers for BC. We thoroughly analyzed the transcriptomic data of two BC cell lines, T47D and UDC4, and performed differential gene expression analysis. We also conducted functional enrichment analysis to understand the biological functions influenced by these genes. Our study identified several diagnostic genes strongly associated with BC, including MIR6728, ENO1-IT1, ENO1-AS1, RNU6-304P, HMGN2P17, RP3-477M7.5, RP3-477M7.6, and CA6. The genes MIR6728, ENO1-IT1, ENO1-AS1, and HMGN2P17 are involved in cancer control, glycolysis, and DNA-related processes, while CA6 is associated with apoptosis and cancer development. These genes could potentially serve as predictors for BC, paving the way for more precise diagnostic methods and personalized treatment plans. This research enhances our understanding of BC and offers promising avenues for improving patient care in the future.

miR-192 family in breast cancer: Regulatory mechanisms and diagnostic value

There is a growing interest in the role of the miRNA family in human cancer. The miRNA-192 family is a group of conserved small RNAs, including miR-192, miR-194, and miR-215. Recent studies have shown that the incidence and mortality of breast cancer have been increasing epidemiologically year by year, and it is urgent to clarify the pathogenesis of breast cancer and seek new diagnostic and therapeutic methods. There is increasing evidence that miR-192 family members may be involved in the occurrence and development of breast cancer. This review describes the regulatory mechanism of the miRNA-192 family affecting the malignant behavior of breast cancer cells and evaluates the value of the miRNA-192 family as a diagnostic and prognostic biomarker for breast cancer. It is expected that summarizing and discussing the relationship between miRNA-192 family members and breast cancer, it will provide a new direction for the clinical diagnosis and treatment of breast cancer and basic medical research.

Circulating exosomal miRNAs as a promising diagnostic biomarker in cancer

Cancer belongs to multifactorial diseases characterized by uncontrolled growth and proliferation of abnormal cells. Breast cancer, non-small cell lung cancer, and colorectal cancer are the most frequently diagnosed malignancies with a high mortality rate. These carcinomas typically contain multiple genetically distinct subpopulations of tumor cells leading to tumor heterogeneity, which promotes the aggressiveness of the disease. Early diagnosis is necessary to increase patient progression-free survival. Particularly, miRNAs present in exosomes derived from tumors represent potential biomarkers suitable for early cancer diagnosis. Identification of miRNAs by liquid biopsy enables a personalized approach with the subsequent better clinical management of patients. This review article highlights the potential of circulating exosomal miRNAs in early breast, non-small cell lung, and colorectal cancer diagnosis.

Exosomal miRNAs and breast cancer: a complex theranostics interlink with clinical significance

Breast cancer (BC) remains the most challenging global health crisis of the current decade, impacting a large population of females annually. In the field of cancer research, the discovery of extracellular vesicles (EVs), specifically exosomes (a subpopulation of EVs), has marked a significant milestone. In general, exosomes are released from all active cells but tumour cell-derived exosomes (TDXs) have a great impact (TDXs miRNAs, proteins, lipid molecules) on cancer development and progression. TDXs regulate multiple events in breast cancer such as tumour microenvironment remodelling, immune cell suppression, angiogenesis, metastasis (EMT-epithelial mesenchymal transition, organ-specific metastasis), and therapeutic resistance. In BC, early detection is the most challenging event, exosome-based BC screening solved the problem. Exosome-based BC treatment is a sign of the transforming era of liquid biopsy, it is also a promising therapeutic tool for breast cancer. Exosome research goes to closer precision oncology via a single exosome profiling approach. Our hope is that this review will serve as motivation for researchers to explore the field of exosomes and develop an efficient, and affordable theranostics approach for breast cancer.

Biological Implications of MicroRNAs as Regulators and Biomarkers of Therapeutic Toxicities in Breast Cancer

Contemporary breast cancer management includes surgical resection combined with a multimodal approach, including chemotherapy, radiotherapy, endocrine therapy, and targeted therapies. Breast cancer treatment is now personalised in accordance with disease and host factors, which has translated to enhanced outcomes for the vast majority of patients. Unfortunately, the treatment of the disease involves patients developing treatment-induced toxicities, with cardiovascular and metabolic side effects having negative implications for long-term quality-of-life metrics. MicroRNAs (miRNAs) are a class of small non-coding ribonucleic acids that are 17 to 25 nucleotides in length, which have utility in modifying genetic expression by working at a post-transcriptional cellular level. miRNAs have involvement in modulating breast cancer development, which is well described, with these biomarkers acting as important regulators of disease, as well as potential diagnostic and therapeutic biomarkers. This review focuses on highlighting the role of miRNAs as regulators and biomarkers of disease, particularly in breast cancer management, with a specific mention of the potential value of miRNAs in predicting treatment-related cardiovascular toxicity.

An Epidemiological Systematic Review with Meta-Analysis on Biomarker Role of Circulating MicroRNAs in Breast Cancer Incidence

Breast cancer (BC) is a multifactorial disease caused by an interaction between genetic predisposition and environmental exposures. MicroRNAs are a group of small non-coding RNA molecules, which seem to have a role either as tumor suppressor genes or oncogenes and seem to be related to cancer risk factors. We conducted a systematic review and meta-analysis to identify circulating microRNAs related to BC diagnosis, paying special attention to methodological problems in this research field. A meta-analysis was performed for microRNAs analyzed in at least three independent studies where sufficient data to make analysis were presented. Seventy-five studies were included in the systematic review. A meta-analysis was performed for microRNAs analyzed in at least three independent studies where sufficient data to make analysis were presented. Seven studies were included in the MIR21 and MIR155 meta-analysis, while four studies were included in the MIR10b metanalysis. The pooled sensitivity and specificity of MIR21 for BC diagnosis were 0.86 (95%CI 0.76-0.93) and 0.84 (95%CI 0.71-0.92), 0.83 (95%CI 0.72-0.91) and 0.90 (95%CI 0.69-0.97) for MIR155, and 0.56 (95%CI 0.32-0.71) and 0.95 (95%CI 0.88-0.98) for MIR10b, respectively. Several other microRNAs were found to be dysregulated, distinguishing BC patients from healthy controls. However, there was little consistency between included studies, making it difficult to identify specific microRNAs useful for diagnosis.

A panel of blood-derived miRNAs with a stable expression pattern as a potential pan-cancer detection signature

Introduction: MicroRNAs have a significant role in the regulation of the transcriptome. Several miRNAs have been proposed as potential biomarkers in different malignancies. However, contradictory results have been reported on the capability of miRNA biomarkers in cancer detection. The human biological clock involves molecular mechanisms that regulate several genes over time. Therefore, the sampling time becomes one of the significant factors in gene expression studies. Method: In the present study, we have tried to find miRNAs with minimum fluctuation in expression levels at different time points that could be more accurate candidates as diagnostic biomarkers. The small RNA-seq raw data of ten healthy individuals across nine-time points were analyzed to identify miRNAs with stable expression. Results: We have found five oscillation patterns. The stable miRNAs were investigated in 779 small-RNA-seq datasets of eleven cancer types. All miRNAs with the highest differential expression were selected for further analysis. The selected miRNAs were explored for functional pathways. The predominantly enriched pathways were miRNA in cancer and the P53-signaling pathway. Finally, we have found seven miRNAs, including miR-142-3p, miR-199a-5p, miR-223-5p, let-7d-5p, miR-148b-3p, miR-340-5p, and miR-421. These miRNAs showed minimum fluctuation in healthy blood and were dysregulated in the blood of eleven cancer types. Conclusion: We have found a signature of seven stable miRNAs which dysregulate in several cancer types and may serve as potential pan-cancer biomarkers.

Plasma Extracellular Vesicles-Derived miR-99a-5p: A Potential Biomarker to Predict Early Head and Neck Squamous Cell Carcinoma

Purpose: This study aimed to investigate the applicability of plasma extracellular vesicles (EVs) miR-99a-5p as a potential head and neck squamous cell carcinoma (HNSCC) diagnostic biomarker.

Methods: The miRNA expression of HNSCC tissue and plasma EVs were profiled by small RNA sequencing. qRT-PCR was performed to detect miR-99a-5p expression in HNSCC (n = 93) and benign disease (n = 39) plasma EVs and formalin-fixed and paraffin-embedded (FFPE) tissue (n = 110). We constructed receiver-operating characteristic curves to investigate the diagnostic efficiency of plasma EVs miR-99a-5p.

Results: Tumor tissue exhibited lower miR-99a-5p than para-tumor tissue. Patients with high miR-99a-5p expression exhibited significantly more p16 positive status. In contrast, HNSCC plasma EVs harbored more miR-99a-5p than the benign disease group. Plasma EVs miR-99a-5p distinguished HNSCC with area under the curve (AUC) of 0.7494 (95% CI: 0.6692–0.8296; p < 0.0001), with 61.54% sensitivity and 75.27% specificity, respectively. Furthermore, plasma EVs miR-99a-5p also distinguished early HNSCC with AUC of 0.7394 (95% CI: 0.6284–0.8504; p = 0.0002), with 79.07% sensitivity and 61.54% specificity, respectively.

Conclusion: Plasma EVs miR-99a-5p is a potential biomarker for predicting early HNSCC.

Mitochondrial miRNAs (MitomiRs): Their potential roles in breast and other cancers

Breast cancer is the most common cancer in women worldwide. MicroRNAs (miRNAs) are non-coding RNAs that are involved in the post-transcriptional regulation of gene expression. Although miRNAs mainly act in the cytoplasm, they can be found in the mitochondrial compartment of the cell. These miRNAs called "MitomiR", they can change mitochondrial functions by regulating proteins at the mitochondrial level and cause cancer. In this review, we have aimed to explain miRNA biogenesis, transport pathways to mitochondria, and summarize mitomiRs that have been shown to play an important role in mitochondrial function, especially in the initiation and progression of breast cancer.

Dysregulation of miR-411 in cancer: Causative factor for pathogenesis, diagnosis and prognosis

MiRNA accounts for 1-3% of genes but regulates more than 30% of gene expression in humans. This article analyzes the current deficiencies and challenges of miR-411 research and looks forward to the prospects of miR-411 in cancer. MiR-411 is a non-coding RNA located on chromosome 14. MiR-411 is abnormally expressed in a variety of cancers. The dysregulation of miR-411 can affect cancer cell proliferation, invasion, migration, apoptosis, colony formation, etc. miR-411 can be regulated by different lncRNAs and circRNAs. By targeting multiple genes, miR-411 participates in the activation of the MAPK signaling pathway, PI3K/AKT/mTOR signaling pathway, p53 signaling pathway, Ras signaling pathway, NF-κB signaling pathway, and Wnt/β-catenin signaling pathway. The expression of miR-411 is related to the diagnosis, prognosis, and sensitivity of drugs in cancer patients. In conclusion, this work outlines the molecular mechanisms and cellular functions of aberrant expression of miR-411 and its target genes in cancer to reveal its potential value in diagnosis, prognosis, and drug sensitivity.

MicroRNAs as Potential Biomarkers for Exercise-Based Cancer Rehabilitation in Cancer Survivors

Expression and functions of microRNAs (miRNAs) have been widely investigated in cancer treatment-induced complications and as a response to physical activity, respectively, but few studies focus on the application of miRNAs as biomarkers in exercise-based cancer rehabilitation. Research has shown that certain miRNA expression is altered substantially due to tissue damage caused by cancer treatment and chronic inflammation. MiRNAs are released from the damaged tissue and can be easily detected in blood plasma. Levels of the miRNA present in peripheral circulation can therefore be used to measure the extent of tissue damage. Moreover, damage to tissues such as cardiac and skeletal muscle significantly affects the individual's health-related fitness, which can be determined using physiologic functional assessments. These physiologic parameters are a measure of tissue health and function and can therefore be correlated with the levels of circulating miRNAs. In this paper, we reviewed miRNAs whose expression is altered during cancer treatment and may correlate to physiological, physical, and psychological changes that significantly impact the quality of life of cancer survivors and their role in response to physical activity. We aim to identify potential miRNAs that can not only be used for monitoring changes that occur in health-related fitness during cancer treatment but can also be used to evaluate response to exercise-based rehabilitation and monitor individual progress through the rehabilitation programme.

LncRNA SNHG5 promotes the glycolysis and proliferation of breast cancer cell through regulating BACH1 via targeting miR-299

Background

Breast cancer (BC) is one of the most common malignant tumors in women. Accumulating studies have been reported that long non-coding RNA (lncRNA) SNHG5 is highly expressed in BC. However, the specific molecular mechanism of SNHG5 in BC is unclear.

Methods

Gene and protein expressions in BC cell were detected by qRT-PCR and western blotting. The proliferation and cell cycle were measured using colony formation assay and flow cytometry analysis, separately. The glucose consumption and lactate production were determined by using the glucose assay kit and lactate assay kit. A dual-luciferase reporter assay was performed to measure the interaction between miR-299 and SNHG5 or BACH1.

Results

SNHG5 and BACH1 expressions were increased in BC cell while miR-299 level was decreased. SNHG5 increased BACH1 expression by directly targeting miR-299. SNHG5 silencing or miR-299 overexpression suppressed the proliferation of BC cell, arrested the cell cycle in the G1 cell phase, and decreased the glucose consumption and lactate production of BC cell. However, inhibition of miR-299 or overexpression of BACH1 could reverse the inhibitory effects of sh-SNHG5 on cell proliferation and glycolysis in BC.

Conclusion

SNHG5 promoted the BC cell growth and glycolysis through up-regulating BACH1 expression via targeting miR-299. These findings may improve the diagnostic and therapeutic approaches to BC.

miRNome and Functional Network Analysis of PGRMC1 Regulated miRNA Target Genes Identify Pathways and Biological Functions Associated With Triple Negative Breast Cancer

Background

Increased expression of the progesterone receptor membrane component 1, a heme and progesterone binding protein, is frequently found in triple negative breast cancer tissue. The basis for the expression of PGRMC1 and its regulation on cellular signaling mechanisms remain largely unknown. Therefore, we aim to study microRNAs that target selective genes and mechanisms that are regulated by PGRMC1 in TNBCs.

Methods

To identify altered miRNAs, whole human miRNome profiling was performed following AG-205 treatment and PGRMC1 silencing. Network analysis identified miRNA target genes while KEGG, REACTOME and Gene ontology were used to explore altered signaling pathways, biological processes, and molecular functions.

Results

KEGG term pathway analysis revealed that upregulated miRNAs target specific genes that are involved in signaling pathways that play a major role in carcinogenesis. While multiple downregulated miRNAs are known oncogenes and have been previously demonstrated to be overexpressed in a variety of cancers. Overlapping miRNA target genes associated with KEGG term pathways were identified and overexpression/amplification of these genes was observed in invasive breast carcinoma tissue from TCGA. Further, the top two genes (CCND1 and YWHAZ) which are highly genetically altered are also associated with poorer overall survival.

Conclusions

Thus, our data demonstrates that therapeutic targeting of PGRMC1 in aggressive breast cancers leads to the activation of miRNAs that target overexpressed genes and deactivation of miRNAs that have oncogenic potential.

Emerging Evidence of the Functional Impact of the miR379/miR656 Cluster (C14MC) in Breast Cancer

Many microRNAs exist in clusters that share comparable sequence homology and may target genes in a common pathway. The miR-379/miR-656 (C14MC) cluster is imprinted in the DLK1-Dio3 region of 14q32.3 and contains 42 miRNAs. It plays a functional role in numerous biological pathways including vascular remodeling and early development. With many C14MC miRNAs highlighted as potential tumor suppressors in a variety of cancers, the role of this cluster in breast cancer (BC) has garnered increased attention in recent years. This review focuses on C14MC in BC, providing an overview of the constituent miRNAs and addressing each in terms of functional impact, potential target genes/pathways, and, where relevant, biomarker capacity. Studies have revealed the regulation of key factors in disease progression and metastasis including tyrosine kinase pathways and factors critical to epithelial–mesenchymal transition (EMT). This has potentially important clinical implications, with EMT playing a critical role in BC metastasis and tyrosine kinase inhibitors (TKIs) in widespread use for the treatment of BC. While the majority of studies have reported tumor-suppressing roles for these miRNAs, some have highlighted their potential as oncomiRs. Understanding the collective contribution of miRNAs within C14MC to BC may support improved understanding of disease etiology and present novel approaches to targeted therapy.

Vasculogenic Mimicry in Breast Cancer: Clinical Relevance and Drivers

In solid tumors, vasculogenic mimicry (VM) is the formation of vascular structures by cancer cells, allowing to generate a channel-network able to transport blood and tumor cells. While angiogenesis is undertaken by endothelial cells, VM is assumed by cancer cells. Besides the participation of VM in tumor neovascularization, the clinical relevance of this process resides in its ability to favor metastasis and to drive resistance to antiangiogenic therapy. VM occurs in many tumor types, including breast cancer, where it has been associated with a more malignant phenotype, such as triple-negative and HER2-positive tumors. The latter may be explained by known drivers of VM, like hypoxia, TGFB, TWIST1, EPHA2, VEGF, matrix metalloproteinases, and other tumor microenvironment-derived factors, which altogether induce the transformation of tumor cells to a mesenchymal phenotype with a high expression rate of stemness markers. This review analyzes the current literature in the field, including the participation of some microRNAs and long noncoding RNAs in VM-regulation and tumorigenesis of breast cancer. Considering the clinical relevance of VM and its association with the tumor phenotype and clinicopathological parameters, further studies are granted to target VM in the clinic.

Comprehensive Analysis of lncRNA and miRNA Regulatory Network Reveals Potential Prognostic Non-coding RNA Involved in Breast Cancer Progression

Breast cancer is one of the most common malignant tumors in women and is the second leading cause of cancer deaths among women. The tumorigenesis and progression of breast cancer are not well understood. The existing researches have indicated that non-coding RNAs, which mainly include long non-coding RNA (lncRNA) and microRNA (miRNA), have gradually become important regulators of breast cancer. We aimed to screen the differential expression of miRNA and lncRNA in the different breast cancer stages and identify the key non-coding RNA using TCGA data. Based on series test of cluster (STC) analysis, bioinformatics analysis, and negatively correlated relationships, 122 lncRNAs, 67 miRNAs, and 119 mRNAs were selected to construct the regulatory network of lncRNA and miRNA. It was shown that the miR-93/20b/106a/106b family was at the center of the regulatory network. Furthermore, 6 miRNAs, 10 lncRNAs, and 15 mRNAs were significantly associated with the overall survival (OS, log-rank P < 0.05) of patients with breast cancer. Overexpressed miR-93 in MCF-7 breast cancer cells was associated with suppressed expression of multiple lncRNAs, and these downregulated lncRNAs (MESTIT1, LOC100128164, and DNMBP-AS1) were significantly associated with poor overall survival in breast cancer patients. Therefore, the miR-93/20b/106a/106b family at the core of the regulatory network discovered by our analysis above may be extremely important for the regulation of lncRNA expression and the progression of breast cancer. The identified key miRNA and lncRNA will enhance the understanding of molecular mechanisms of breast cancer progression. Targeting these key non-coding RNA may provide new therapeutic strategies for breast cancer treatment and may prevent the progression of breast cancer from an early stage to an advanced stage.

Plasma Circulating Mirnas Profiling for Identification of Potential Breast Cancer Early Detection Biomarkers

Objective:

This study aimed to characterize the miRNA expression profiles from plasma samples of our local breast cancer patients in comparison to healthy control by using miRNA PCR Array.

Methods:

In this study, plasma miRNA profiles from eight early-stage breast cancer patients and nine age-matched (± 2 years) healthy controls were characterized by miRNA array-based approach, followed by differential gene expression analysis, Independent T-test and construction of Receiver Operating Characteristic (ROC) curve to determine the capability of the assays to discriminate between breast cancer and the healthy control.

Results:

Based on the 372-miRNAs microarray profiling, a set of 40 differential miRNAs was extracted regarding to the fold change value at 2 and above. We further sub grouped 40 miRNAs of breast cancer patients that were significantly expressed at 2-fold change and higher. In this set, we discovered that 24 miRNAs were significantly upregulated and 16 miRNAs were significantly downregulated in breast cancer patients, as compared to the miRNA expression of healthy subjects. ROC curve analysis revealed that seven miRNAs (miR-125b-5p, miR-142-3p, miR-145-5p, miR-193a-5p, miR-27b-3p, miR-22-5p and miR-423-5p) had area under curve (AUC) value > 0.7 (AUC p-value < 0.05). Overlapping findings from differential gene expression analysis, ROC analysis, and Independent T-Test resulted in three miRNAs (miR-27b-3p, miR-22-5p, miR-145-5p). Cohen’s effect size for these three miRNAs was large with d value are more than 0.95.

Conclusion:

miR-27b-3p, miR-22-5p, miR-145-5p could be potential biomarkers to distinguish breast cancer patients from healthy controls. A validation study for these three miRNAs in an external set of samples is ongoing.

Nanoporous Anodic Alumina-Based Sensor for miR-99a-5p Detection as an Effective Early Breast Cancer Diagnostic Tool

Circulating microRNAs have emerged as potential diagnostic biomarkers. The deregulation of the microRNA miR-99a-5p has been previously described as an effective biomarker of early breast cancer. Herein, we present a new nanoporous anodic alumina (NAA)-based biosensor that can detect plasma miR-99a-5p with high sensitivity and selectivity. NAA pores are loaded with rhodamine B and capped with a specific oligonucleotide that is able to block cargo release until the target is present. In the presence of miR-99a-5p, the capping oligonucleotide recognizes the miR-99a-5p sequence and displaces it allowing the release of the encapsulated dye. This method is able to successfully distinguish healthy controls from breast cancer patients, even at early stages with high efficiency, showing the presented system as a promising tool for breast cancer detection.

Profiling microRNAs in uncomplicated pregnancies: Serum vs. plasma

Blood-derived microRNAs (miRNAs/miRs) are ideal clinical biomarkers, as they can be relatively non-invasively extracted and are stable across a range of storage conditions. However, the concentration and profile of miRNAs differ between specific patient groups and starting media, which must be a key consideration before embarking upon uses for clinical applications. The optimum blood-derived starting media for biomarker discovery involving pregnant women with an uncomplicated pregnancy has not been determined. Paired serum and plasma samples were collected from 10 pregnant women with uncomplicated low-risk pregnancies at three time points: i) During the second trimester of pregnancy; ii) during the third trimester; and iii) 6 weeks post-partum. Sample miRNA content was assessed using an Agilent Bioanalyzer Small RNA chip and reverse transcription-quantitative (RT-q)PCR using four constitutively expressed miRNAs: hsa-miR-222-3p, hsa-miR-23a, hsa-miR-30e-5p and hsa-miR-451a. Quality control spike-ins measured RNA extraction (UniSp2) and cDNA extraction (cel-miR-39-3p) efficiency. MiRNA concentration and percentage were significantly higher in the serum vs. plasma samples based on data obtained from the Bioanalyzer; however, RT-qPCR failed to replicate these differences in the majority of comparisons using the ΔCq values of the four constitutively expressed miRNAs. Using the standard deviations of the ΔCq values, the consistency of serum and plasma in terms of miRNA expression levels were equivalent. Thus, clinicians and researchers should take into consideration that different miRNA quantification methods can yield contrasting results with regards to the starting media utilized. Based on the equivalent performance of serum and plasma assessed using RT-qPCR, which is less likely to be influenced by the coagulation process or degraded long RNAs, both starting media assessed in the present study are equally suitable for ongoing biomarker discovery studies involving healthy pregnant women at any gestational time point or immediately postpartum.

MicroRNA 452 regulates ASB8, NOL8, and CDR2 expression in colorectal cancer cells

BACKGROUND

MicroRNAs play important roles in the pathogenesis of human diseases by regulating target gene expression in specific cells or tissues. Previously, we identified microRNA 452 (MIR452), which was specifically up-regulated in early stage human colorectal cancer (CRC) tissue.

OBJECTIVE

The current study aims to identify and verify the target genes of MIR452 associated with CRC.

METHODS

A luciferase reporter system was used to confirm the effect of MIR452 on ASB8, NOL8, and CDR2 expression. The expression levels of MIR452 and the target genes were evaluated by quantitative RT-PCR (qRT-PCR) and western blotting.

RESULTS

We verified the association between MIR452 and three genes, ASB8, NOL8, and CDR2, and showed that their transcripts were down-regulated by MIR452. Up-regulated MIR452 also down-regulated ASB8, NOL8, and CDR2 mRNA and protein levels in CRC cells. CDR2 protein expression was decreased in CRC tissues compared to adjacent non-tumor tissues.

CONCLUSIONS

These results suggest that ASB8, NOL8, and CDR2 were target genes of MIR452 in CRC cells and that up-regulated MIR452 in CRC tissue regulated ASB8, NOL8, and CDR2 expression during colorectal carcinogenesis.

Circulating miR-99a-5p Expression in Plasma: A Potential Biomarker for Early Diagnosis of Breast Cancer

MicroRNAs have emerged as new diagnostic and therapeutic biomarkers for breast cancer. Herein, we analysed miR-99a-5p expression levels in primary tumours and plasma of breast cancer patients to evaluate its usefulness as a minimally invasive diagnostic biomarker. MiR-99a-5p expression levels were determined by quantitative real-time PCR in three independent cohorts of patients: (I) Discovery cohort: breast cancer tissues (n = 103) and healthy breast tissues (n = 26); (II) Testing cohort: plasma samples from 105 patients and 98 healthy donors; (III) Validation cohort: plasma samples from 89 patients and 85 healthy donors. Our results demonstrated that miR-99a-5p was significantly downregulated in breast cancer tissues compared to healthy breast tissues. Conversely, miR-99a-5p levels were significantly higher in breast cancer patients than in healthy controls in plasma samples from both testing and validation cohorts, and ROC curve analysis revealed that miR-99a-5p has good diagnostic potential even to detect early breast cancer. In conclusion, miR-99a-5p’s deregulated expression distinguished healthy patients from breast cancer patients in two different types of samples (tissues and plasma). Interestingly, expression levels in plasma were significantly lower in healthy controls than in early-stage breast cancer patients. Our findings suggest circulating miR-99a-5p as a novel promising non-invasive biomarker for breast cancer detection.

Scutellaria barbata and Hedyotis diffusa herb pair for breast cancer treatment: Potential mechanism based on network pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

The Scutellaria barbata and Hedyotis diffusa (SH) herb pair is extensively used in Traditional Chinese Medicine for efficacy enhancement in cancer treatment in China and Asian countries. Superior clinical efficacy observations based on high dosages (≥60 g) motivated us to explore appropriate dosages and the underlying mechanisms of action.

AIM OF THE STUDY

To explore the efficacy and potential mechanisms of actions of SH through in vitro and in vivo experiments and network pharmacology.

MATERIALS AND METHODS

SH lyophilized powder (SHLP) was prepared from decoctions and the active ingredients were identified using high performance liquid chromatography (HPLC). Proliferation and migration experiments in vitro and tumor growth in vivo were performed to evaluate the effects of SHLP on breast cancer. Corresponding potential target genes for SHLP components and breast cancer were extracted from established databases and the Protein-Protein Internetwork of shared genes were constructed using STRING database. Kyoto Encyclopedia of Genes and Genomes (KEGG) functional annotation clusters were acquired and the top 30 pathways were presented. At last, as one of pathways indicated by enriched results, apoptosis was validated with flow cytometric analysis and caspase-3, 8, 9 activities.

RESULTS

Seventy-five ingredients were identified from SHLP by HPLC. High SHLP doses inhibited proliferation and migration of three types of breast cancer cells in vitro and tumor growth in nude mice. After target genes extraction and intersection, the top 30 KEGG clusters were enriched, including PI3K-Akt, cell cycle and other related pathways like VEGF, Micro-RNAs and NF-κB, besides, key genes in apoptosis were mapped. In the last, apoptosis was validated by flow cytometric analysis and caspase-3, 8, 9 activities after SHLP treatment.

CONCLUSION

High SHLP dosages inhibited breast cancer in vitro and in vivo, enriched by network pharmacology and confirmed by flow cytometric analysis and caspase activation, with apoptosis was identified as one of the mechanisms of action of SHLP. SHLP administration with higher doses is recommended for clinical usage.

Liquid biopsy for breast cancer using extracellular vesicles and cell-free microRNAs as biomarkers

Improvement of breast cancer (BC) patient's outcome is directly related to early detection. However, there is still a lack of reliable biomarkers for diagnosis, prognosis and, treatment follow up in BC, leading researchers to study the potential of liquid biopsy based on circulating microRNAs (c-miRNAs). These c-miRNAs can be cell-free or associated with extracellular vesicles (EVs), and have great advantages such as stability in biofluids, noninvasive accessibility compared to current techniques (core-biopsy and surgery), and expression associated with pathogenic conditions. Recently, a new promising field of EV-derived miRNAs (EV-miRNAs) as cancer biomarkers has emerged, receiving special attention due to their selective vesicle sorting which makes them accurate for disease detection. In this review, we discuss new findings about c-miRNA and their potential as biomarkers for BC diagnosis, prognosis, and therapy. Additionally, we address the impact of limitations associated with the standardization of analysis techniques and methods on the implementation of these biomarkers in the clinical setting.

Blood Circulating Exosomes Contain Distinguishable Fractions of Free and Cell-Surface-Associated Vesicles

BACKGROUND

Considering exosomes as intercellular transporters, inevitably interacting with the plasma membrane and the large available surface of blood cells, we wonder if a fraction of circulating exosomes is associated with the surface of blood cells.

OBJECTIVE

The aim of this study was to develop an efficient protocol for isolating exosomes associated with the surface of blood cells and to further investigate the characteristics of this fraction in a healthy state and during the development of breast cancer, as well as its possible implication for use in diagnostic applications.

METHODS

Blood samples were collected from Healthy Females (HFs) and breast cancer patients (BCPs). Exosomes extracted from blood plasma and eluted from the surface of blood cells were isolated by ultrafiltration with subsequent ultracentrifugation.

RESULTS

Transmission Electron Microscopy (TEM), along with immunogold labeling, demonstrated the presence of exosomes among membrane-wrapped extracellular vesicles (EVs) isolated from both plasma and blood cell eluates. TEM, nanoparticle tracking analysis, and NanoOrange protein quantitation data showed that cell-associated exosomes constituted no less than 2/3 of total blood exosome number. Exosomes, ranging from 50-70 nm in size, prevailed in the blood of breast cancer patients, whereas smaller exosomes (30-50 nm) were mostly observed in the blood of healthy women. Analysis of specific proteins and RNAs in exosomes circulating in blood demonstrated the significant differences in the packing density of the polymers in exosomes of HFs and BCPs. Preliminary data indicated that detection of cancer-specific miRNA (miR-103, miR-191, miR-195) in exosomes associated with the fraction of red blood cells allowed to discriminate HFs and BCPs more precisely compared to cell-free exosomes circulating in plasma.

CONCLUSION

Our data provide the basis for using blood cell-associated exosomes for diagnostic applications.

Secreted breast tumor interstitial fluid microRNAs and their target genes are associated with triple-negative breast cancer, tumor grade, and immune infiltration

Background

Studies on tumor-secreted microRNAs point to a functional role of these in cellular communication and reprogramming of the tumor microenvironment. Uptake of tumor-secreted microRNAs by neighboring cells may result in the silencing of mRNA targets and, in turn, modulation of the transcriptome. Studying miRNAs externalized from tumors could improve cancer patient diagnosis and disease monitoring and help to pinpoint which miRNA-gene interactions are central for tumor properties such as invasiveness and metastasis.

Methods

Using a bioinformatics approach, we analyzed the profiles of secreted tumor and normal interstitial fluid (IF) microRNAs, from women with breast cancer (BC). We carried out differential abundance analysis (DAA), to obtain miRNAs, which were enriched or depleted in IFs, from patients with different clinical traits. Subsequently, miRNA family enrichment analysis was performed to assess whether any families were over-represented in the specific sets. We identified dysregulated genes in tumor tissues from the same cohort of patients and constructed weighted gene co-expression networks, to extract sets of co-expressed genes and co-abundant miRNAs. Lastly, we integrated miRNAs and mRNAs to obtain interaction networks and supported our findings using prediction tools and cancer gene databases.

Results

Network analysis showed co-expressed genes and miRNA regulators, associated with tumor lymphocyte infiltration. All of the genes were involved in immune system processes, and many had previously been associated with cancer immunity. A subset of these, BTLA, CXCL13, IL7R, LAMP3, and LTB, was linked to the presence of tertiary lymphoid structures and high endothelial venules within tumors. Co-abundant tumor interstitial fluid miRNAs within this network, including miR-146a and miR-494, were annotated as negative regulators of immune-stimulatory responses. One co-expression network encompassed differences between BC subtypes. Genes differentially co-expressed between luminal B and triple-negative breast cancer (TNBC) were connected with sphingolipid metabolism and predicted to be co-regulated by miR-23a. Co-expressed genes and TIF miRNAs associated with tumor grade were BTRC, CHST1, miR-10a/b, miR-107, miR-301a, and miR-454.

Conclusion

Integration of IF miRNAs and mRNAs unveiled networks associated with patient clinicopathological traits, and underlined molecular mechanisms, specific to BC sub-groups. Our results highlight the benefits of an integrative approach to biomarker discovery, placing secreted miRNAs within a biological context.

Dissecting miRNA facilitated physiology and function in human breast cancer for therapeutic intervention

MicroRNAs (miRNAs) are key epigenomic regulators of biological processes in animals and plants. These small non coding RNAs form a complex networks that regulate cellular function and development. MiRNAs prevent translation by either inactivation or inducing degradation of mRNA, a major concern in post-transcriptional gene regulation. Aberrant regulation of gene expression by miRNAs is frequently observed in cancer. Overexpression of various 'oncomiRs' and silencing of tumor suppressor miRNAs are associated with various types of human cancers, although overall downregulation of miRNA expression is reported as a hallmark of cancer. Modulations of the total pool of cellular miRNA by alteration in genetic and epigenetic factors associated with the biogenesis of miRNA machinery. It also depends on the availability of cellular miRNAs from its store in the organelles which affect tumor development and cancer progression. Here, we have dissected the roles and pathways of various miRNAs during normal cellular and molecular functions as well as during breast cancer progression. Recent research works and prevailing views implicate that there are two major types of miRNAs; (i) intracellular miRNAs and (ii) extracellular miRNAs. Concept, that the functions of intracellular miRNAs are driven by cellular organelles in mammalian cells. Extracellular miRNAs function in cell-cell communication in extracellular spaces and distance cells through circulation. A detailed understanding of organelle driven miRNA function and the precise role of extracellular miRNAs, pre- and post-therapeutic implications of miRNAs in this scenario would open several avenues for further understanding of miRNA function and can be better exploited for the treatment of breast cancers.

Towards a more precise and individualized assessment of breast cancer risk

Many clinically based models are available for breast cancer risk assessment; however, these models are not particularly useful at the individual level, despite being designed with that intent. There is, therefore, a significant need for improved, precise individualized risk assessment. In this Research Perspective, we highlight commonly used clinical risk assessment models and recent scientific advances to individualize risk assessment using precision biomarkers. Genome-wide association studies have identified >100 single nucleotide polymorphisms (SNPs) associated with breast cancer risk, and polygenic risk scores (PRS) have been developed by several groups using this information. The ability of a PRS to improve risk assessment is promising; however, validation in both genetically and ethnically diverse populations is needed. Additionally, novel classes of biomarkers, such as microRNAs, may capture clinically relevant information based on epigenetic regulation of gene expression. Our group has recently identified a circulating-microRNA signature predictive of long-term breast cancer in a prospective cohort of high-risk women. While progress has been made, the importance of accurate risk assessment cannot be understated. Precision risk assessment will identify those women at greatest risk of developing breast cancer, thus avoiding overtreatment of women at average risk and identifying the most appropriate candidates for chemoprevention or surgical prevention.

Kinesin family member 11 is a potential therapeutic target and is suppressed by microRNA-30a in breast cancer

Kinesin family member 11 (KIF11) is a plus end‐directed kinesin indispensable for the formation of the bipolar spindle in metaphase, where it objects to the action of minus end‐directed molecular motors. Here, we hypothesize that KIF11 might be a therapeutic target of breast cancer and regulated by miR‐30a. Cell Counting Kit 8 assays were used to investigate cell proliferation. Invasion assays were used to survey the motility of cells. Kaplan‐Meier and Cox proportional analyses were employed for this outcome study. The prognostic significance and performance of KIF11 were validated on 17 worldwide independent microarray datasets and two The Cancer Genome Atlas‐Breast Invasive Carcinoma sets. microRNA was predicted targeting KIF11 through sequence alignment in microRNA.org and confirmed by coexpression analysis in human breast cancer samples. Dual‐luciferase reporter assays were employed to validate the interaction between miR‐30a and KIF11 further. Higher KIF11 mRNA levels and lower miR‐30a were significantly associated with poor survival of breast cancer patients. Inhibition of KIF11 by small‐hairpin RNA significantly reduced the proliferation and invasion capabilities of the breast cancer cells. Meanwhile, downregulation of KIF11 could enhance the cytotoxicity of adriamycin in breast cancer cell lines MCF‐7 and MDA‐MB‐231. A population study also validated that chemotherapy and radiotherapy significantly improved survival in early‐stage breast cancer patients with low KIF11 expression levels. Further bioinformatics analysis demonstrated that miR‐30a could interact with KIF11 and validated by dual‐luciferase reporter assays. Therefore, KIF11 is a potential therapeutic target of breast cancer. miR‐30a could specifically interact with KIF11 and suppress its expression in breast cancer.

LINC00467 enhances head and neck squamous cell carcinoma progression and the epithelial-mesenchymal transition process via miR-299-5p/ubiquitin specific protease-48 axis

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) has attracted the attention of researchers as a result of its high incidence around the world. This malignancy occurs in the oral cavity, pharynx and larynx in most cases. A number of lncRNAs have been revealed to regulate the malignant neoplasia of several cancers. Nevertheless, the effects of lncRNA LINC00467 in HNSCC have not yet been reported.

METHODS

The expression of LINC00467, miR-299-5p and ubiquitin specific protease-48 (USP48) in HNSCC cells was quantified by a quantitative reverse transcriptase-polymerase chain reaction. The influences of LINC00467 deficiency on HNSCC progression were reflected by cell counting kit-8, colony formation, ethynyl-2-deoxyuridine, wound healing and western blot assays. RIP and luciferase reporter assays were conducted to confirm the interaction among LINC00467, miR-299-5p and USP48.

RESULTS

LINC00467 was considerably upregulated in HNSCC cells, and an absence of LINC00467 suppressed cell growth, cell migration and the epithelial-mesenchymal process in HNSCC. In addition, miR-299-5p expression was notably downregulated in HNSCC cells, and miR-299-5p could bind with LINC00467. Furthermore, USP48 was conspicuously overexpressed in HNSCC cells and capable of binding with miR-299-5p. LINC00467 could upregulate USP48 expression via sponging miR-299-5p. Finally, rescue assays proved that USP48 overexpression could compensate for the suppressive effects on HNSCC progression mediated by LINC00467 deficiency.

CONCLUSIONS

LINC00467 enhances HNSCC progression by serving as a sponge of miR-299-5p to increase USP48 expression.

Cell-free miRNAs as non-invasive biomarkers in breast cancer: Significance in early diagnosis and metastasis prediction

Breast cancer is one of the genetic diseases causing a high mortality among women around the world. Despite the availability of advanced diagnostic tools and treatment strategies, the incidence of breast cancer is increasing every year. This is due to the lack of accurate and reliable biomarkers whose deficiency creates difficulty in early breast cancer recognition, subtypes determination, and metastasis prophecy. Although biomarkers such as ER, PR, Her2, Ki-67, and other genetic platforms e.g. MammaPrint®, Oncotype DX®, Prosigna® or EndoPredict® are available for determination of breast cancer diagnosis and prognosis. However, pertaining to heterogeneous nature, lack of sensitivity, and specificity of these markers, it is still incessant to overcome breast cancer burden. Therefore, a novel biomarker is urgently needed for therapeutic diagnosis and improving prognosis. Lately, it has become more evident that cell-free miRNAs might be useful as good non-invasive biomarkers that are associated with different events in carcinogenesis. For example, some known biomarkers such as miR-21, miR-23a, miR-34a are associated with molecular subtyping and different biomolecular aspects i.e. apoptosis, angiogenesis, metastasis, and miR-1, miR-10b, miR-16 are associated with drug response. Cell-free miRNAs present in human body fluids have proven to be potential biomarkers with significant prognostic and predictive values. Numerous studies have found a distinct expression profile of circulating miRNAs in breast tumour versus non-tumour and in early and advanced-stage, thus implicating its clinical relevance. This review article will highlight the importance of different cell-free miRNAs as a biomarker for early breast cancer detection, subtype classification, and metastasis forecast.

MicroRNA‑299‑5p inhibits cell metastasis in breast cancer by directly targeting serine/threonine kinase 39

Numerous studies have demonstrated that microRNAs (miRNAs) play a key role in human carcinogenesis and metastasis. For example, miR‑299‑5p has previously been revealed to be dysregulated in several human cancers. However, the biological function of miR‑299‑5p in breast cancer remains unclear. The present study demonstrated that miR‑299‑5p was downregulated in breast cancer tissues and cell lines. The restoration of miR‑299‑5p expression suppressed cell migration and invasion, whereas inhibition of miR‑299‑5p promoted cell migration and invasion. In addition, in vivo studies demonstrated that miR‑299‑5p overexpression was able to inhibit tumour metastasis in nude mice. Mechanistically, through bioinformatics analysis and a dual‑luciferase assay, it was confirmed that miR‑299‑5p directly targets serine/threonine kinase 39 (STK39). Silencing STK39 inhibited cell metastasis and suppressed epithelial‑mesenchymal transition markers and matrix metalloproteinase expression, whereas restoration of STK39 expression was able to reverse miR‑299‑5p‑inhibited cell migration and invasion. Collectively, the results of the present study demonstrated that miR‑299‑5p supresses breast cancer cell migration and invasion by targeting STK39. These findings may provide novel insights into miR‑299‑5p and its potential diagnostic and therapeutic benefits in breast cancer.

MicroRNA 452 Regulates Cell Proliferation, Cell Migration, and Angiogenesis in Colorectal Cancer by Suppressing VEGFA Expression

The human microRNA 452 (MIR452) was identified as a colorectal cancer (CRC)-associated micro RNA (miRNA) by miRNA expression profiling of human CRC tissues versus normal colorectal tissues. It was significantly up-regulated in human CRC tissues. However, the functional mechanisms of MIR452 and its target genes in CRC remain unclear. We identified 27 putative MIR452 target genes, and found that the vascular endothelial growth factor A (VEGFA) was a direct target gene of MIR452. Both cellular and extracellular VEGFA levels were significantly downregulated in CRC cells upon their transfection with MIR452 or siVEGFA. VEGFA expression was frequently downregulated in human CRC tissues in comparison with that in their healthy counterparts. We showed that MIR452 regulated the expression of genes in the VEGFA-mediated signal transduction pathways vascular endothelial growth factor receptor 1 (VEGFR2)-mitogen-activated protein kinase (MAPK) and VEGFR2-SRC proto-oncogene non-receptor tyrosine kinase (SRC) in CRC cells. Immunohistological analyses of xenografted MIR452-overexpressing CRC cells in mice showed that MIR452 regulated cell proliferation and angiogenesis. Furthermore, aortic ring angiogenesis assay in rats clearly showed that the number of microvessels formed was significantly reduced by MIR452 transfection. Our findings suggest that MIR452 regulates cell proliferation, cell migration, and angiogenesis by suppressing VEGFA expression in early CRC progression; therefore, MIR452 may have therapeutic value in relation to human CRC.

Circulating miRNAs as Diagnostic and Prognostic Biomarkers in Common Solid Tumors: Focus on Lung, Breast, Prostate Cancers, and Osteosarcoma

An early cancer diagnosis is essential to treat and manage patients, but it is difficult to achieve this goal due to the still too low specificity and sensitivity of classical methods (imaging, actual biomarkers), together with the high invasiveness of tissue biopsies. The discovery of novel, reliable, and easily collectable cancer markers is a topic of interest, with human biofluids, especially blood, as important sources of minimal invasive biomarkers such as circulating microRNAs (miRNAs), the most promising. MiRNAs are small non-coding RNAs and known epigenetic modulators of gene expression, with specific roles in cancer development/progression, which are next to be implemented in the clinical routine as biomarkers for early diagnosis and the efficient monitoring of tumor progression and treatment response. Unfortunately, several issues regarding their validation process are still to be resolved. In this review, updated findings specifically focused on the clinical relevance of circulating miRNAs as prognostic and diagnostic biomarkers for the most prevalent cancer types (breast, lung, and prostate cancers in adults, and osteosarcoma in children) are described. In addition, deep analysis of pre-analytical, analytical, and post-analytical issues still affecting the circulation of miRNAs' validation process and routine implementation is included.

The Regulatory Role of MicroRNAs in Breast Cancer

MicroRNAs (miRNAs) are small non-coding RNA molecules which function as critical post-transcriptional gene regulators of various biological functions. Generally, miRNAs negatively regulate gene expression by binding to their selective messenger RNAs (mRNAs), thereby leading to either mRNA degradation or translational repression, depending on the degree of complementarity with target mRNA sequences. Aberrant expression of these miRNAs has been linked etiologically with various human diseases including breast cancer. Different cellular pathways of breast cancer development such as cell proliferation, apoptotic response, metastasis, cancer recurrence and chemoresistance are regulated by either the oncogenic miRNA (oncomiR) or tumor suppressor miRNA (tsmiR). In this review, we highlight the current state of research into miRNA involved in breast cancer, with particular attention to articles published between the years 2000 to 2019, using detailed searches of the databases PubMed, Google Scholar, and Scopus. The post-transcriptional gene regulatory roles of various dysregulated miRNAs in breast cancer and their potential as therapeutic targets are also discussed.

Deregulated miRNAs in osteoporosis: effects in bone metastasis

Starting from their role exerted on osteoblast and osteoclast differentiation and activity pathways, microRNAs (miRNAs) have been recently identified as regulators of different processes in bone homeostasis. For this purpose, in a recent review, we highlighted, as deregulated miRNAs could be involved in different bone diseases such as osteoporosis. In addition, recent studies supported the concept that osteoporosis-induced bone alterations might offer a receptive site for cancer cells to form bone metastases, However, to date, no data on specific-shared miRNAs between osteoporosis and bone metastases have been considered and described to clarify the evidence of this link. The main goal of this review is to underline as deregulated miRNAs in osteoporosis may have specific roles in the development of bone metastases. The review showed that several circulating osteoporotic miRNAs could facilitate tumor progression and bone-metastasis formation in several tumor types, i.e., breast cancer, prostate cancer, non-small-cell lung cancer, esophageal squamous cell carcinoma, and multiple myeloma. In detail, serum up-regulation of pro-osteoporotic miRNAs, as well as serum down-regulation of anti-osteoporotic miRNAs are common features of all these tumors and are able to promote bone metastasis. These results are of key importance and could help researcher and clinicians to establish new therapeutic strategies connected with deregulation of circulating miRNAs and able to interfere with pathogenic processes of osteoporosis, tumor progressions, and bone-metastasis formation.

A five-miRNA panel in plasma was identified for breast cancer diagnosis

Breast cancer (BC) is one of the most common cancers in females. Since early detection can bring prognosis benefit, discovery of novel noninvasive biomarkers for BC diagnosis is in urgent need. In this four‐phase study, we profiled miRNA expression in plasma samples from a total of 257 BC patients and 257 normal controls (NCs). Exiqon miRNA qPCR panel was used to select candidate miRNAs in the screening phase which were further analyzed using qRT‐PCR in the following training, testing and external validation phases. Finally, we identified five plasma miRNAs (let‐7b‐5p, miR‐122‐5p, miR‐146b‐5p, miR‐210‐3p and miR‐215‐5p) whose expression levels were significantly different between BC patients and NCs. A 5‐miRNA panel in plasma with high sensitivity and specificity was then constructed to detect BC. The areas under the receiver‐operating characteristic curves (AUCs) of the panel were 0.683, 0.966, 0.978 for the training, testing and external validation sets, respectively. Expression of the identified miRNAs was further analyzed among 32 pairs of BC tissue and the adjacent normal tissue samples as well as plasma‐derived exosome samples from 32 BC patients vs 32 NCs. Let‐7b‐5p was contrarily down‐regulated in BC tissue. In exosomes samples, only miR‐122‐5p was significantly up‐regulated as in plasma for BC patients. In conclusion, we identified a 5‐miRNA plasma panel (let‐7b‐5p, miR‐122‐5p, miR‐146b‐5p, miR‐210‐3p and miR‐215‐5p) that could serve as a promising biomarker for BC detection.

Clinical Translatability of "Identified" Circulating miRNAs for Diagnosing Breast Cancer: Overview and Update

The effective management of patients with breast cancer (BC) depends on the early diagnosis of the disease. Currently, BC diagnosis is based on diagnostic imaging and biopsy, while the use of non-invasive circulating biomarkers for diagnosis remains an unmet need. Among the plethora of proposed non-invasive biomarkers, circulating microRNAs (miRNAs) have been considered promising diagnostic molecules because they are very stable in biological fluids and easily detectable. Although the discovery of miRNAs has opened a new avenue for their clinical application, the clinical translatability of these molecules remains unclear. This review analyses the role of circulating miRNAs as BC diagnostic biomarkers and focuses on two essential requirements to evaluate their clinical validity: i) Specificity and ii) consistent expression between the blood and tissue. These two issues were analyzed in depth using the Human miRNA Disease Database (HMDD v3.0) and the free search engine PubMed. One hundred and sixty three BC-associated miRNAs were selected and analyzed for their specificity among all human pathologies that shared deregulation (291) and consistent expression in the bloodstream and the tissue. In addition, we provide an overview of the current clinical trials examining miRNAs in BC. In conclusion, we highlight pitfalls in the translatability of circulating miRNAs into clinical practice due to the lack of specificity and a consistent expression pattern between the tissue and blood.

Construction of a circRNA-miRNA-mRNA network to explore the pathogenesis and treatment of pancreatic ductal adenocarcinoma

BACKGROUND

Many studies focusing on circular RNAs (circRNAs) have recently been published. However, a large number of circRNAs remain to be explored. This study was designed to discover new circRNAs and investigate their potential roles in the pathogenesis of pancreatic ductal adenocarcinoma (PDAC).

METHODS

A combination of gene chip analysis and bioinformatic methods was utilized to reveal new circRNAs and their possible mechanisms in PDAC. A circRNA-miRNA-mRNA network was established based on the results of differential analyses and interaction predictions. Promising drugs for treating PDAC were determined by connectivity map (CMap) analysis.

RESULTS

Expression profile data were collected from the Gene Expression Omnibus database, and integration of differentially expressed circRNAs (DECs) from two gene chips using the RobustRankAggreg method revealed 10 DECs. The microRNA (miRNA) response elements of these 10 DECs were predicted. The predicted miRNAs and differentially expressed miRNAs were intersected, and 12 overlapping miRNAs were acquired. Next, 2908 miRNA target mRNAs and 1187 differentially expressed genes (DEGs) in PDAC were identified and combined, revealing 118 overlapping mRNAs. A protein-protein interaction network was constructed with the 118 mRNAs, and four hub genes (CDH1, SERPINE1, IRS1 and FYN) were identified. Using Gene Expression Profiling Interactive Analysis, survival analyses were conducted for the four hub genes, and SERPINE1 and FYN were found to be significantly associated with PDAC patient survival. Functional enrichment analysis indicated that these four hub genes are closely associated with certain cancer-related biological functions and pathways. In addition, CMap analysis based on the four hub genes was performed to screen potential therapeutic agents for PDAC, and three bioactive chemicals (celastrol, 5109870 and MG-132) were discovered.

CONCLUSIONS

The results of this study further our understanding of the pathogenesis and treatment of PDAC from the perspective of the circRNA-related competing endogenous RNA network.

Gene Expression and miRNAs Profiling: Function and Regulation in Human Epidermal Growth Factor Receptor 2 (HER2)-Positive Breast Cancer

Breast cancer is the second most common cause of cancer-related deaths among women worldwide. It is a heterogeneous disease with four major molecular subtypes. One of the subtypes, human epidermal growth factor receptor 2 (HER2)-enriched (HER2-positive) is characterized by the absence of estrogen and progesterone receptors and overexpression of HER2 receptor, and accounts for 15–20% of all breast cancers. Despite the anti-HER2 and cytotoxic chemotherapy, HER2 subtype is an aggressive disease with significant mortality. Recent advances in molecular biology techniques, including gene expression profiling, proteomics, and microRNA analysis, have been extensively used to explore the underlying mechanisms behind human breast carcinogenesis and metastasis including HER2-positive breast cancer, paving the way for developing new targeted therapies. This review focuses on recent advances on gene expression and miRNA status in HER2-positive breast cancer.

A new insight on serum microRNA expression as novel biomarkers in breast cancer patients

Breast cancer (BC) is one of the widespread lethal diseases affecting a large number of women worldwide. As such, employing and identifying significant markers for detecting BC in different stages can assist in better diagnosis and management of the disease. Several diverse markers have been introduced for diagnosis, but their limitations, including low specificity and sensitivity, reduce their application. microRNAs (miRNAs), as short noncoding RNAs, have been shown to significantly influence gene expression in different disease pathologies, especially BC. Clearly, among different samples used for detecting miRNA expressions, circulating miRNAs present as promising and useful biomarkers. Among different body fluid samples, serum serves as one of the most reliable samples, thanks to its high stability under various severe conditions and some unique features. Extensive research has suggested that BC-related miRNAs can remain stable in the serum. The objective of this review is to describe different samples used for detecting miRNAs in BC subjects with emphasis on serum miRNAs. So, this study highlights serum miRNAs with the potential of acting as biomarkers for different stages of BC. We reviewed the possible correlation between potential miRNAs and the risk of early breast cancer, metastatic breast cancer, response to chemotherapy, and relapse.

Blood Circulating miRNAs as Cancer Biomarkers for Diagnosis and Surgical Treatment Response

miRNAs can function as potential oncogenes or tumor suppressors. Altered expression of these molecules was correlated with the occurrence of many cancer diseases and therefore they are considered a molecular tool for non-invasive cancer diagnosis and prognosis. We searched for analyses concerning expression of blood circulating miRNA in cancer patients. The studies comprised of at least two miRNA expression measurements: before and after the surgical therapy were considered. We summarized latest reports on evaluation of the efficiency of anticancer therapy through observation of changes in expression of miRNA circulating in blood of patients treated with surgery alone. Twenty one research studies were identified. Thirty one different miRNAs were pointed out as potential both diagnostic and treatment response biomarkers since their deregulated expression before therapy returned to normal after receiving the treatment. Published data revealed a potential of circulating miRNA to become a tool giving a clinical follow up information on the efficiency of applied therapy. However, more observational studies on post-operative circulating miRNA expression changes are necessary.

Liquid Biopsy beyond Circulating Tumor Cells and Cell-Free DNA

Liquid biopsy represents the analysis of tumor-derived material in the blood and other body fluids of cancer patients. This portrays a minimally invasive detection tool for molecular biomarkers. Liquid biopsy has emerged as a complementary or alternative method to surgical biopsy. This non-invasive detection tool overcomes the recurrent problems in the clinical assessment of tumors that stem from the lack of accessibility to the tumor tissue and its clonal heterogeneity. Moreover, body fluid-derived components have shown to reflect the genetic profile of both primary and metastatic lesions and provide a real-time monitoring of tumor dynamics, representing a great promise for personalized medicine. This review will highlight the latest breakthroughs and the current applications of several tumor-derived biomarkers that can be found in body fluids. The authors will focus on tumor-derived exosomes, tumor-educated platelets, and circulating tumor miRNAs and mRNAs, and how these can be used for tumor detection.

Gene co-expression network approach for predicting prognostic microRNA biomarkers in different subtypes of breast cancer

New diagnostic miRNA biomarkers for different types of cancer have been studied extensively, particularly for breast cancer (BC), which is a leading cause of death among women and has many different subtypes. In the present study, a systems biology approach was used to find remarkable and novel miRNA biomarkers for five molecular subtypes of BC: luminal A, luminal B, ERBB2, basal-like and normal-like. The mRNA expression data from the five BC subtypes was used to reconstruct co-expression networks. The important mRNA-miRNA interactions were considered when reconstructing the bipartite networks from which the five bipartite sub-networks were reconstructed for further analysis. The novel biomarkers detected for each subtype are as follows: miRNAs 26b-5p and 124-3p for basal-like, 26b-5p, 124-3p and 5011-5p for ERBB2, 26b-5p and 5011-5p for LumA, 124-3p, 26b-5p and 7-5p for LumB and 26b-5p, 124-3p and 193b-3p for normal-like. The roles of the identified miRNAs in the occurrence or development of each subtype of BC remain unclear and should be investigated in future studies. In addition, the target genes of these miRNAs may be critical to the mechanisms underlying each subtype and should be analyzed as therapeutic targets in future studies.

3D Mammary Epithelial Cell Models: A Goldmine of DCIS Biomarkers and Morphogenetic Mechanisms

Breast ductal carcinoma in situ (DCIS) has been typically recognized by pathologists on the basis of aberrant mammary duct morphology. Thus, there are increasing efforts to detect DCIS biomarkers and druggable targets. In this study we focused on the molecular mechanism involving Annexin A8 (ANXA8), a Ca²⁺ and phospholipid binding protein, which is regulated by all-trans Retinoic Acid (RA), and it is highly expressed in breast DCIS tissue samples relative to atypical ductal hyperplasia, and normal breast tissue. Using a panel of human mammary epithelial HME1 cell lines that share a common protein signature, and develop in vitro three dimensional (3D) “DCIS-like” amorphous structures, we identified by bioinformatics analysis protein-miRNA pairs, potentially involved in mammary morphogenetic mechanisms, including the ANXA8 mechanism. HME1 cells with genetic mutations hampering the physiological RA regulation of the RA receptor alpha (RARA) transcriptional function, but retain the RARA function controlling the PI3KCA-AKT signaling, develop 3D “DCIS-like” amorphous structures with upregulated ANXA8. Consistently, ectopic ANXA8 expression, by affecting the RARA transcriptional function, induced HME1 DCIS-like amorphous acini expressing phosphorylated AKT (P-AKT). Apparently, a RA-RARA-ANXA8 feedback loop fosters a vicious circle of aberrant morphogenesis. Interestingly, a few miRNAs regulated by RA are predicted to target ANXA8 mRNA. These miRNAs are candidate components of the RA-RARA-ANXA8 mechanism, and their deregulation might induce DCIS initiation.

Plasma MicroRNA Pair Panels as Novel Biomarkers for Detection of Early Stage Breast Cancer

Introduction: Breast cancer is the second leading cause of cancer death among females. We sought to identify microRNA (miRNA) markers in breast cancer, and determine whether miRNA expression is predictive of early stage breast cancer. The paired panel of microRNAs is promising. Methods: Global miRNA expression profiling was performed on three pooling samples of plasma from breast cancer, benign lesion and normal, using next generation sequencing technology. Thirteen microRNAs (hsa-miR-21-3p, hsa-miR-192-5p, hsa-miR-221-3p, hsa-miR-451a, hsa-miR-574-5p, hsa-miR-1273g-3p, hsa-miR-152, hsa-miR-22-3p, hsa-miR-222-3p, hsa-miR-30a-5p, hsa-miR-30e-5p, hsa-miR-324-3p, and hsa -miR-382-5p) were subsequently validated using real-time quantitative reverse transcription-polymerase chain reaction (RT-qPCR) in a cohort of 53 breast cancer, 40 benign lesions and 38 normal cases. The pairwise miRNA ratios were calculated as biomarkers to classify breast cancer. Results: According to the model used to predict breast cancer from benign lesions, a panel of five miRNA pairs had high diagnostic power with an AUC of 0.942. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of this model after 10-fold cross validation were 0.881, 0.775, 0.827, and 0.756, respectively. In addition, the other panels of miRNA pairs distinguishing the breast cancer from normal and non-cancer patients had good performance. Conclusion: Certain MicroRNA pairs were identified and deemed effective in breast cancer screening, especially when distinguishing cancer from benign lesions.