Low Expression of Circulating MicroRNA-34c is Associated with Poor Prognosis in Triple-Negative Breast Cancer

PURPOSE

The microRNA-34 (miR-34) family is important in tumor regulation. This study aimed to investigate the association of circulating miR-34 family proteins with clinicopathological features and their prognostic value in triple-negative breast cancer (TNBC) patients.

MATERIALS AND METHODS

In this cohort study, 173 TNBC patients admitted to First People's Hospital of Shunde from May 1, 2009 to April 30, 2013 were enrolled. Meanwhile, 75 age-matched healthy women volunteers were identified as healthy controls (HCs). We examined the expression of miR-34 family (miR-34a/b/c) proteins in plasma collected from TNBC patients before any treatment was performed and from age-matched HCs using qPCR methods.

RESULTS

The expressions of miR-34a/34b/34c were significantly lower in TNBC patients than in HC (p<0.001, p=0.027, p<0.001, respectively). miR-34a was correlated with tumor grade (p=0.038), lymph node positive (p=0.027), distant metastasis (p=0.004), and surgery (p=0.023); miR-34b was correlated with lymph node positivity (p=0.027); and miR-34c was correlated with tumor grade (p=0.017) and distant metastasis (p<0.001). Kaplan-Meier curve analysis displayed low expression of miR-34a as associated with worse overall survival (OS) (p=0.011), as well as miR-34c low expression (p=0.002). In addition, univariate and multivariate Cox proportional hazards regression was performed, and low expression of miR-34c (p=0.011) was found to be an independent risk factor for OS, as well as tumor grade (p=0.013), lymph node positive (p=0.050), and distant metastasis (p=0.021).

CONCLUSION

In conclusion, this study demonstrated reduced miR-34a/c expression is highly associated with tumor progression and indicated worse prognosis. Also, miR-34c was an independent risk factor for OS in TNBC patients.

Changes in plasma miR-9, miR-16, miR-205 and miR-486 levels after non-small cell lung cancer resection

PURPOSE

The majority of non-small cell lung cancer (NSCLC) patients presents with an advanced-stage disease and, consequently, exhibits a poor overall survival rate. We aimed to assess changes in plasma miR-9, miR-16, miR-205 and miR-486 levels and their potential as biomarkers for the diagnosis and monitoring of NSCLC patients.

METHODS

Plasma was collected from 50 healthy donors and from NSCLC patients before surgery (n = 61), 1 month after surgery (n = 37) and 1 year after surgery (n = 14). microRNA levels were quantified using qRT-PCR.

RESULTS

We found in NSCLC patients before treatment, both with squamous cell carcinoma (SQCC) and adenocarcinoma (ADC), significantly higher plasma miR-16 and miR-486 levels than in healthy individuals. Pre-treatment miR-205 concentrations were found to be significantly higher in SQCC than in ADC patients, and only SQCC patients presented significantly higher circulating miR-205 levels than healthy donors. SQCC plasma miR-9 levels were not different from normal control levels, but in ADC they were found to be significantly decreased. A combination of plasma miR-16, miR-205 and miR-486 measurements was found to discriminate NSCLC patients from healthy persons, with a specificity of 95% and a sensitivity of 80%. Following tumor resection, we found that the miR-9 and miR-205 levels significantly decreased, even below the normal level, whereas the increased miR-486 level persisted up to one year after surgery, and the miR-16 level decreased to normal. After tumor resection, none of the miR levels tested was found to relate to recurrence.

CONCLUSIONS

Our data indicate that miR-9, miR-16, miR-205 and miR-486 may serve as NSCLC biomarkers. The observed cancer-related pre- and post-operative changes in their plasma levels may not only reflect the presence of a primary cancer, but also of a systemic response to cancer.

Relationship between circulating microRNA-30c with total- and LDL-cholesterol, their circulatory transportation and effect of statins

BACKGROUND

Small non-coding microRNAs (miR) have important regulatory roles and are used as biomarkers of disease. We investigated the relationship between lipoproteins and circulating miR-30c, evaluated how they are transported in circulation and determined whether statins altered the circulating concentration of miR-30c.

METHODS

To determine the relationship between lipoproteins and circulating miR-30c, serum samples from 79 subjects recruited from a lipid clinic were evaluated. Ultracentrifugation and nanoparticle tracking analysis was used to evaluate the transportation of miR-30c in the circulation by lipoproteins and extracellular vesicles in three healthy volunteers. Using archived samples from previous studies, the effects of 40mg rosuvastatin (n=22) and 40mg pravastatin (n=24) on miR-30c expression was also examined. RNA extraction, reverse transcription-quantitative real-time polymerase chain reaction was carried out using standard procedures.

RESULTS

When stratified according to total cholesterol concentration, there was increased miR-30c expression in the highest compared to the lowest tertile (p=0.035). There was significant positive correlation between miR-30c and total- (r=0.367; p=0.002) and LDL-cholesterol (r=0.391; p=0.001). We found that miR-30c was transported in both exosomes and on HDL3. There was a 3.8-fold increased expression of circulating miR-30c after pravastatin treatment for 1year (p=0.005) but no significant change with atorvastatin after 8weeks (p=0.145).

CONCLUSIONS

This study shows for the first-time in humans that circulating miR-30c is significantly, positively correlated with total- and LDL-cholesterol implicating regulatory functions in lipid homeostasis. We show miR-30c is transported in both exosomes and on HDL3 and pravastatin therapy significantly increased circulating miR-30c expression adding to the pleiotropic dimensions of statins.

Analysis of the Distribution Profiles of Circulating MicroRNAs by Asymmetrical Flow Field Flow Fractionation

MicroRNAs (miRNAs) are stably present in circulatory systems. They are bound to various carriers like proteins, lipoprotein particles, and exosomes. Investigating the process of miRNA distribution among these carriers will help improve our understanding of their functions in the extracellular environment and their potential relationship with diseases. Here, we describe how to obtain the distribution profiles of circulating miRNAs by separation of different miRNA carriers in human serum with asymmetrical flow field flow fractionation (AF4), and detection of the miRNAs in the eluted fractions that enrich particular types of carriers with RT-qPCR.

A novel serum microRNA signature to screen esophageal squamous cell carcinoma

Circulating microRNAs (miRNAs) have been used as promising diagnostic biomarkers for esophageal squamous cell carcinoma (ESCC). We performed miRNA expression profiling using quantitative reverse transcription polymerase chain reaction (qRT‐PCR) based Exiqon panels from three ESCC pools and one normal control (NC) pool samples. Using qRT‐PCR, identified serum miRNAs were further confirmed in training (32 ESCC vs. 32 NCs) and testing stages (108 ESCC vs. 96 NCs). Consequently, five serum miRNAs (miR‐20b‐5p, miR‐28‐3p, miR‐192‐5p, miR‐223‐3p, and miR‐296‐5p) were significantly overexpressed in ESCC compared with NCs. The diagnostic value of the 5‐miRNA signature was validated by an external cohort (60 ESCC vs. 60 NCs). The areas under the receiver operating characteristic curve (ROC) of the 5‐miRNA signature were 0.753, 0.763, and 0.966 for the training, testing, and the external validation stages, respectively. The expression levels of the miRNAs were also determined in tissues, arterial serum, and exosomes. MiR‐20b‐5p, miR‐28‐3p, and miR‐192‐5p were significantly upregulated in ESCC tissues, while miR‐296‐5p was overexpressed in ESCC serum exosomes. In conclusion, we identified a 5‐miRNA signature in serum for the detection of ESCC.

MiR-148a the epigenetic regulator of bone homeostasis is increased in plasma of osteoporotic postmenopausal women

BACKGROUND

Osteoporosis is a prevalent skeletal disorder characterized by reduced bone mineral density and microarchitectural deterioration of bone tissue, resulting in bone fragility and low-trauma fractures. Imaging techniques are routinely used to detect low bone mass; however, they are unable to identify deterioration of bone quality. Recently, microRNAs have emerged as regulators of bone remodelling and potentially also as a new class of sensitive biomarkers of bone health to aid in diagnosis and treatment monitoring of osteoporosis.

METHODS

To identify new plasma-based biomarkers associated with osteoporosis we analyzed microRNAs isolated from plasma samples of 74 postmenopausal women divided into osteoporotic (N = 17) and control groups (N = 57). A prior microRNA screening was performed where a few showed promise for further analysis. Quantitative polymerase chain reaction was used to investigate differences in expression of let-7d-5p, let-7e-5p, miR-30d-5p, miR-30e-5p, miR-126-3p, miR-148a-3p, miR-199a-3p, miR-423-5p and miR-574-5p between the two groups. Furthermore, correlation analysis between microRNA expression levels and patient bone mineral density measurements and fracture risk assessment tool (FRAX) as well as trabecular bone scores were performed.

RESULTS

Expression of miR-148a-3p was significantly higher (p = 0.042) in the osteoporotic patient group compared to the controls. In addition, we identified correlations between miR-126-3p (ρ = 0.253, p = 0.032) and 423-5p (ρ = -0.230, p = 0.049) and parameters of bone quality and quantity.

CONCLUSION

The results from our study, together with the functional role of miR-148a-3p in bone suggest that this microRNA could be considered as a potential new plasma-based biomarker for pathological changes associated with osteoporosis.

Circulating microRNAs as novel biomarkers for bone diseases - Complex signatures for multifactorial diseases?

Biomarkers are essential tools in clinical research and practice. Useful biomarkers must combine good measurability, validated association with biological processes or outcomes, and should support clinical decision making if used in clinical practice. Several types of validated biomarkers have been reported in the context of bone diseases. However, because these biomarkers face certain limitations there is an interest in the identification of novel biomarkers for bone diseases, specifically in those that are tightly linked to the disease pathology leading to increased fracture-risk. MicroRNAs (miRNAs) are the most abundant RNA species to be found in cell-free blood. Encapsulated within microvesicles or bound to proteins, circulating miRNAs are remarkably stable analytes that can be measured using gold-standard technologies such as quantitative polymerase-chain-reaction (qPCR). Nevertheless, the analysis of circulating miRNAs faces several pre-analytical as well as analytical challenges. From a biological view, there is accumulating evidence that miRNAs play essential roles in the regulation of various biological processes including bone homeostasis. Moreover, specific changes in miRNA transcription levels or miRNA secretory levels have been linked to the development and progression of certain bone diseases. Only recently, results from circulating miRNAs analysis in patients with osteopenia, osteoporosis and fragility fractures have been reported. By comparing these findings to studies on circulating miRNAs in cellular senescence and aging or muscle physiology and sarcopenia, several overlaps were observed. This suggests that signatures observed during osteoporosis might not be specific to the pathophysiology in bone, but rather integrate information from several tissue types. Despite these promising first data, more work remains to be done until circulating miRNAs can serve as established and robust diagnostic tools for bone diseases in clinical research, clinical routine and in personalized medicine.

A restricted signature of serum miRNAs distinguishes glioblastoma from lower grade gliomas

Background

Malignant gliomas are the most common primary brain tumors in adults and challenging cancers for diagnosis and treatment. They remain a disease for which non-invasive, diagnostic and/or prognostic novel biomarkers are highly desirable. Altered microRNA (miRNA) profiles have been observed in tumor tissues and biological fluids. To date only a small set of circulating/serum miRNA is found to be differentially expressed in brain tumors compared to normal controls.

Here a restricted signature of circulating/serum miRNA including miR-15b*,-23a, −99a, −125b, −133a, −150*, −197, −340, −497, −548b-5p and let-7c were investigated as potential non-invasive biomarkers in the diagnosis of glioma patients.

Methods

Serum and tissues miRNAs expression in patients with brain cancers (n = 30) and healthy controls (n = 15) were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Relative expression was calculated using the comparative Ct method. Statistical significance (p ≤ 0,05) was determined using the Mann–Whitney rank sum and Fisher’s exact test. Diagnostic accuracy of miRNAs in distinguishing glioblastoma multiforme (GBM) from lower grade cancer was assessed by the Receiver Operating Characteristic (ROC) curve analysis.

To validate the role of the identified miRNAs in cancer a comprehensive literature search was conducted using PubMed, Web of Science (Core Collection) and Scopus databases.

Results

We observed a decrease of miR-497 and miR-125b serum levels depending on tumor stages with reduced level in GBM than lower grade tumors. The ROC curve analysis distinguishing GBM from lower grade cases yielded an area under the curve (AUC) of 0.87 (95 % confidence interval (CI) = 0.712–1) and of 0.75 (95 % CI = 0.533–0.967) for miR-497 and -125b, respectively. GBM patients are more likely to show a miR-497 and -125b down-regulation than the lower grade group (p = 0.002 and p = 0.024, respectively). These results were subsequently compared with evidence from 19 studies included in the final systematic review.

Conclusions

Although multiple biomarkers are currently leveraged in the clinic to detect specific cancer types, no such standard blood biomolecules are used as yet in gliomas. Our data suggest that serum miR-497 and -125b could be a novel diagnostic markers with good perspectives for future clinical applications in patients with glioma.

Circulating Extracellular Vesicles Contain miRNAs and are Released as Early Biomarkers for Cardiac Injury

Plasma-circulating microRNAs have been implicated as novel early biomarkers for myocardial infarction (MI) due to their high specificity for cardiac injury. For swift clinical translation of this potential biomarker, it is important to understand their temporal and spatial characteristics upon MI. Therefore, we studied the temporal release, potential source, and transportation of circulating miRNAs in different models of ischemia reperfusion (I/R) injury. We demonstrated that extracellular vesicles are released from the ischemic myocardium upon I/R injury. Moreover, we provided evidence that cardiac and muscle-specific miRNAs are transported by extracellular vesicles and are rapidly detectable in plasma. Since these vesicles are enriched for the released miRNAs and their detection precedes traditional damage markers, they hold great potential as specific early biomarkers for MI.

Identifying circulating microRNAs as biomarkers of cardiovascular disease: a systematic review

The aim of the present study is to identify microRNAs (miRs) with high potential to be used as biomarkers in plasma and/or serum to clinically diagnose, or provide accurate prognosis for survival in, patients with atherosclerosis, coronary artery disease, and acute coronary syndrome (ACS). A systematic search of published original research yielded a total of 72 studies. After review of the risk of bias of the published studies, according to Cochrane Collaboration and the QUADUAS Group standards, 19 studies were selected. Overall 52 different miRs were reported. In particular, miR-133a/b (5 studies), miR-208a/b (6 studies), and miR-499 (7 studies) were well studied and found to be significant diagnostic and/or prognostic markers across different cardiovascular disease progression stages. miR-1 and miR-145b are potential biomarkers of ACS; miR-1 with higher sensitivity for all acute myocardial infarction (AMI), and miR-145 for STEMI and worse outcome of AMI. But when miRs were studied across different ACS study populations, patients had varying degrees of coronary stenosis, which was identified as an important confounder that limited the ability to quantitatively pool the study results. The identified miRs were found to regulate endothelial function and angiogenesis (miR-1, miR-133), vascular smooth muscle cell differentiation (miR-133, miR-145), communication between vascular smooth muscle and endothelial cell to stabilize plaques (miR-145), apoptosis (miR-1, miR-133, miR-499), cardiac myocyte differentiation (miR-1, miR-133, miR-145, miR-208, miR-499), and to repress cardiac hypertrophy (miR-133). Their role in these processes may be explained by regulation of shared RNA targets such as cyclin-dependent kinase inhibitor 1A (or p21), ETS proto-oncogene 1, fascin actin-bundling protein 1, hyperpolarization-activated cyclic nucleotide-gated potassium channel 4, insulin-like growth factor 1 receptor LIM and SH3 protein 1, purine nucleoside phosphorylase, and transgelin 2. These mechanistic data further support the clinical relevance of the identified miRs. miR-1, miR-133a/b, miR-145, miR-208a/b, and miR-499(a) in plasma and/or serum show some potential for diagnosis of cardiovascular disease. However, biased selection of miRs in most studies and unexplained contrasting results are major limitations of current miR research. Inconsistencies need to be addressed in order to definitively identify clinically useful miRs. Therefore, this paper presents important aspects to improve future miR research, including unbiased selection of miRs, standardization/normalization of reference miRs, adjustment for patient comorbidities and medication, and robust protocols of data-sharing plans that could prevent selective publication and selective reporting of miR research outcomes.

Intracellular and extracellular microRNA: An update on localization and biological role

MicroRNA (miRNA) is a class of small non-coding RNAs which mediate post-transcriptional gene silencing (PTGS) by sequence-specific inhibition of target mRNAs translation and/or lowering their half-lives in the cytoplasm. Together with their binding partners, Argonaute (AGO) proteins, miRNAs form cores of RNA-induced silencing complexes (RISC). Despite a substantial progress in understanding RISC structure, until recently little was known about its localization in the cell. This review is aimed to provide an overview of the emerging picture of miRNA and RISC localization and function both in the intracellular space and outside of the cell. In contrast to the common assumption that PTGS occurs in the cytoplasm, it was found to operate mainly on the membranes of the endoplasmic reticulum (ER). Besides ER membranes miRNAs were found in all main cellular compartments including nucleus, nucleolus and mitochondria where they regulate various processes including transcription, translation, alternative splicing and DNA repair. Moreover, a certain pool of miRNAs may not be associated with RISC and carry completely different functions. Finally, the discovery of cell-free miRNAs in all biological fluids suggests that miRNAs might also act as signaling molecules outside the cell, and may be utilized as biomarkers for a variety of diseases. In this review we discuss miRNA secretion mechanisms and possible pathways of cell-cell communication via miRNA-containing exosomes in vivo.

Circulating microRNAs in Huntington's disease: Emerging mediators in metabolic impairment

Huntington's disease (HD) is a hereditary neurodegenerative disease, with peripheral consequences that negatively contribute to quality of life. Circulating microRNAs (cmiRNAs) are being explored for their roles in intercellular communication and gene expression regulation, which allows gaining insight into the regulation of crosstalk between neuronal and peripheral tissues. Here, we explore the cmiRNA profile of plasma samples from fifteen symptomatic patients, with 40-45 CAG repeats in the HTT gene, and seven healthy matched controls. Isolated miRNAs from plasma samples were run against human miRNome panels, which have sequences for 752 human mature miRNAs. We found that 168 cmiRNAs are altered in symptomatic patients. Considering Bonferroni's correction, miR-877-5p, miR-223-3p, miR-223-5p, miR-30d-5p, miR-128, miR-22-5p, miR-222-3p, miR-338-3p, miR-130b-3p, miR-425-5p, miR-628-3p, miR-361-5p, miR-942 are significantly increased in HD patients as compared with controls. Moreover, after patient's organization according to approved HD scales, miR-122-5p is significantly decreased in HD patients with Unified Huntington's Disease Rating Scale >24, whereas an increase in miR-100-5p levels and a decrease in miR-641 and miR-330-3p levels were recorded when patients were rearranged by Total Functional Capacity. These results suggest that cmiRNA profile could be further modified by disease progression, making cmiRNAs useful as monitoring biomarkers. Analysis of target genes indicated a general overexpression of cmiRNAs implicated in metabolism regulation. Profiling cmiRNA of HD subjects opens the possibility of personalized therapies for different groups of HD patients, based on disease modifiers: regulation of altered pathways might contribute to not only alleviate disease symptoms, but also influence HD progression.

Association between tuberculosis and circulating microRNA hsa-let-7b and hsa-miR-30b: A pilot study in a Chinese population

Tuberculosis remains one of the world's deadliest communicable diseases. Limitations in the current diagnosis tools have heavily slowed down the step to eliminate TB. The objective of this study was to identify potential circulating miRNA associated with tuberculosis (TB) infection and disease development. Agilent human miRNA microarray was used to estimate the circulating levels of 1887 miRNAs among 34 study participants (10 patients with pulmonary TB, 13 controls with latent TB infection and 11 non-infected healthy controls). The identified miRNAs were subsequently verified by real-time qPCR. Target gene prediction and miRNA-gene network construction were further explored. A total of 119 miRNAs were identified to be in different levels between any two groups of the study population by microarray (Fold Change>2, p < 0.01). 11 most promising miRNAs were then selected for verification by real-time qPCR. The levels of hsa-let-7b-5p and hsa-miR-30b-5p were confirmed to be significantly up-regulated in pulmonary TB patients as compared to both control groups (p < 0.01). Caspase 3 was predicted to be one common target gene for these two miRNAs. None of the selected miRNA was confirmed to be related with the infection status. This pilot study suggested circulating hsa-let-7b and hsa-miR-30b might be associated with TB development by regulating the target genes involved in TLR-NF-kB mediated signal pathway.

Circulating microRNAs as novel biomarkers in the diagnosis of prostate cancer: a systematic review and meta-analysis

BACKGROUND

The diagnostic value of circulating microRNAs (miRNAs) detection in prostate cancer (PC) patients is currently under debate. Thus, we performed this meta-analysis of published literature to systematically evaluate the diagnostic potential of circulating miRNAs in PC.

METHODS

Eligible studies were searched in PubMed, Embase and Chinese National Knowledge Infrastructure databases. Sensitivity and specificity were pooled using a random-effects model and were used to plot the summary receiver operator characteristic (SROC) curve. All analyses were performed using the Stata 13.0 software and Meta-Disc 1.4 for windows.

RESULTS

A total of ten articles were included for the meta-analysis according to the inclusion criteria. The pooled results based on all included studies showed circulating miRNAs have a relatively good diagnostic performance, with a sensitivity of 0.74, a specificity of 0.71 and an area under SROC curve (AUC) of 0.77 in indiscriminating PC from controls. Furthermore, meta-regression and subgroup analyses indicate that multiple circulating miRNAs detection displayed a better diagnostic performance than single one, with an AUC rising from 0.75 to 0.81. Additional interesting finding was that Caucasian-based circulating miRNAs assays could reach a higher accuracy compared with non-Caucasian-based one for PC with the p value of 0.0378.

CONCLUSION

Our results confirmed the potential use of circulating miRNAs in the early diagnosis of PC, especially the combination of multiple circulating miRNAs. However, large-scale prospective studies are still needed to further validate our findings.

Plasma levels of increased miR-195-5p correlates with the sFLT-1 levels in preeclampsia

Although the role of soluble fms-like tyrosine kinase 1 (sFLT-1) in preeclampsia is well-established, the mechanism related to its synthesis remains poorly understood. We evaluated the association among the circulating microRNAs (miRs) and sFLT-1 levels in preeclampsia pregnant women. For this purpose, we measured the plasma sFLT-1 levels in 24 preeclampsia women and selected from these, three subjects with the lowest and three with the highest levels of sFLT-1 in order to screen for potential miRs associated with plasmatic sFLT-1 concentrations using a polymerase chain reaction-array (PCR-array) methodology. From screening results, we found three statistically different expressed miRs with fold change (FC-high/low levels) ≥3.0: miR-195-5p (FC = 5.2 increase in group with high sFLT-1 levels), miR-16-5p (FC = 3.2; increase in group with high sFLT-1 levels), and miR-375 (FC = -3.0; decrease in group with high sFLT-1 levels) which were later validated in all samples (n = 24). To correlate these miRs and plasma sFLT-1 levels, we used two extremes of analysis. In one part, we compared 12 preeclampsia women with the lowest sFLT-1 levels (L-50% group) to 12 with the highest levels (50% H group); and in the second analysis, 6 preeclampsia women (L-25%) from the L group to 6 preeclampsia women from the H group (H-25%). Our results showed increased expression of miR-195-5p in the H group, considering both the analyses with 50%, FC = 2.1 and 25%, FC = 4.2. Regarding other miRs, lack of correlation was found in both analyses (50% and 25%). In conclusion, our data demonstrate an association of higher levels of sFLT-1 with increased expression of miR-195-5p in preeclampsia pregnant women.

Potential role of circulating microRNAs as a biomarker for unexplained recurrent spontaneous abortion

OBJECTIVE

To compare circulating microRNA (miRNA) profiles between unexplained recurrent spontaneous abortion (URSA) and normal early pregnancies (NEP) and to evaluate the potential role of circulating miRNA as a biomarker for URSA.

DESIGN

Laboratory study using human plasma samples.

SETTING

Special hospital and research institutes.

PATIENT(S)

From September 2012 to April 2013, samples of plasma were obtained from 27 URSA patients and 28 NEP patients at 6-10 weeks of gestation at the Department of Reproductive Immunology in Family Planning Special Hospital of Guangdong Province.

INTERVENTION(S)

Differential miRNA profiling analysis of plasma collected from URSA and NEP patients was performed with the use of microarray.

MAIN OUTCOME MEASURE(S)

The circulating miRNA expression profile was assessed by means of microarray and real-time quantitative reverse-transcription polymerase chain reaction (qRT-PCR) analysis.

RESULT(S)

Twenty-five circulating miRNAs were expressed differentially in URSA compared with NEP. Of these, nine were overexpressed and 16 down-regulated. Six differentially expressed circulating miRNAs were selected to validate the microarray results, and qRT-PCR data confirmed the reliability of the microarray results. Further analysis showed that four circulating miRNAs (miR-320b, miR-146b-5p, miR-221-3p, miR-559) were up-regulated. In URSA, one circulating miRNA (miR-101-3p) was down-regulated in other larger scale samples according to qRT-PCR. Based on target gene analysis, we speculate that these circulating miRNAs regulate URSA by targeting immune, apoptosis, and angiogenic gene functions.

CONCLUSION(S)

Circulating microRNAs may be involved in URSA pathogenesis and provide a promising new diagnostic biomarker for URSA.

Circulating miRNAs as biomarkers for endocrine disorders

Specific, sensitive and non-invasive biomarkers are always needed in endocrine disorders. miRNAs are short, non-coding RNA molecules with well-known role in gene expression regulation. They are frequently dysregulated in metabolic and endocrine diseases. Recently it has been shown that they are secreted into biofluids by nearly all kind of cell types. As they can be taken up by other cells they may have a role in a new kind of paracrine, cell-to-cell communication. Circulating miRNAs are protected by RNA-binding proteins or microvesicles hence they can be attractive candidates as diagnostic or prognostic biomarkers. In this review, we summarize the characteristics of extracellular miRNA's and our knowledge about their origin and potential roles in endocrine and metabolic diseases. Discussions about the technical challenges occurring during identification and measurement of extracellular miRNAs and future perspectives about their roles are also highlighted.

Differential microRNA Profiles Predict Diabetic Nephropathy Progression in Taiwan

OBJECTIVES

Diabetic nephropathy (DN) is a major leading cause of kidney failure. Recent studies showed that serological microRNAs (miRs) could be utilized as biomarkers to identify disease pathogenesis; the DN-related miRs, however, remained to be explored.

METHODS

A prospective case-control study was conducted. The clinical significance of five potential miRs (miR-21, miR-29a, miR-29b, miR-29c and miR192) in type 2 Diabetes Mellitus (T2DM) patients who have existing diabetic retinopathy with differential Albumin:Creatinine Ratio (ACR) and estimated Glomerular Filtration Rate (eGFR) was performed using quantitative RT-PCR analysis. The subjects with diabetic retinopathy enrolled in Taipei City Hospital, Taiwan, were classified into groups of normal albuminuria (ACR<30mg/g; N=12); microalbuminuria (30mg/g<ACR<300mg/g; N=17) and overt proteinuria (ACR>300mg/g; N=21) as well as 18 low-eGFR (eGFR<60ml/min) and 32 high-eGFR (eGFR>60ml/min). The level of serum miRs was statistically correlated with age, Glucose AC, ACR, eGFR and DN progression.

RESULTS

The levels of miR-21, miR-29a and miR-192 were significantly enriched in the overt proteinuria group compared with microalbuminuria and/or overt proteinuria groups. It was shown that only miR-21 level was significantly up-regulated in low-eGFR group compared with high-eGFR patients. Interestingly, Pearson's correlation coefficient analysis demonstrated that DN progressors showed significantly greater levels of miR-21, miR-29a, miR-29b and miR-29c in comparison with non-progressors implying the clinical potential of DN associated miRs in monitoring and preventing disease advancement.

CONCLUSION

Our findings showed that miR-21, miR-29a/b/c and miR-192 could reflect DN pathogenesis and serve as biomarkers during DN progression.

Are Circulating microRNAs Involved in Tumor Surveillance?

By studying literature data and having performed an in silico analysis, the circulating microRNA expression profiles of healthy individuals appear to show an abundance of microRNAs with predominant tumor suppressor activity. We hypothesize that circulating tumor suppressor microRNAs might constitute a sort of continuous tumor surveillance, whereby circulating microRNAs delivering gene expression modulating epigenetic information might halt cell transformation and tumorigenesis. This mechanism might complement the well-known cancer immune surveillance. A further hypothesis is also discussed, supposing that the tissue specific action of microRNAs might represent a putative defense mechanism against the potential tumor-promoting actions of secreted miRNA.

Circulating Extracellular microRNA in Systemic Autoimmunity

MicroRNAs (miRNAs) are differentially regulated in healthy, activated, inflamed, neoplastic, or otherwise pathological cells and tissues. While their main functions are executed intracellularly, many miRNAs can reproducibly be detected extracellularly in plasma and serum. This circulating, extracellular miRNA is protected against degradation by complexation with carrier proteins and/or by being enclosed in subcellular membrane vesicles. This, together with their tissue- and disease-specific expression, has fuelled the interest in using circulating microRNA profiles as harbingers of disease, i.e., as diagnostic analytes and as clues to dysregulated pathways in disease. Many studies show that inflammation and immune dysregulation, e.g., in autoimmune diseases, are associated with distinct miRNA expression changes in targeted tissues and in innate and adaptive immunity cells such as lymphocytes, natural killer cells, neutrophil granulocytes, and monocyte-macrophages. Exploratory studies (only validated in a few cases) also show that specific profiles of circulating miRNAs are associated with different systemic autoimmune diseases including systemic lupus erythematosus (SLE), systemic sclerosis, and rheumatoid arthritis. Even though the link between cellular alterations and extracellular profiles is still unpredictable, the data suggest that circulating miRNAs in autoimmunity may become diagnostically useful. Here, we review important circulating miRNAs in animal models of inflammation and in systemic autoimmunity and summarize some proposed functions of miRNAs in immune regulation and dysregulation. We conclude that the studies suggest new hypotheses and additional experiments, and that further diagnostic development is highly dependent on analytical method development and on obtaining sufficient numbers of uniformly processed samples from clinically well-characterized patients and controls.

MicroRNAs relate to early worsening of renal function in patients with acute heart failure

BACKGROUND

Deregulation of microRNAs (miRNAs) may be involved in the pathogenesis of heart failure (HF) and renal disease. Our aim is to describe miRNA levels related to early worsening renal function in acute HF patients.

METHOD AND RESULTS

We studied the association between 12 circulating miRNAs and Worsening Renal Function (WRF; defined as an increase in the serum creatinine level of 0.3mg per deciliter or more from admission to day 3), absolute change in creatinine and Neutrophil Gelatinase Associated Lipocalin (NGAL) from admission to day 3 in 98 patients hospitalized for acute HF. At baseline, circulating levels of all miRNAs were lower in patients with WRF, with statistically significant decreased levels of miR-199a-3p, miR-423-3p, and miR-let-7i-5p (p-value<0.05). The increase in creatinine during the first 3 days of hospitalization was significantly associated with lower levels of miR-199a-3p, miR-27a-3p, miR-652-3p, miR-423-5p, and miR-let-7i-5p, while the increase in NGAL was significantly associated with lower levels of miR-18a-5p, miR-106a-5p, miR-223-3p, miR-199a-3p and miR-423-3p. MiR-199a-3p was the strongest predictor of WRF, with an Odds Ratio of 1.48 (1.061-2.065; p-value=0.021) and a C-index of 0.701.

CONCLUSIONS

Our results show that the levels of circulating miRNAs at hospital admission for acute HF were consistently lower in patients who developed worsening of renal function. MiR-199a-3p was the best predictor of WRF in these patients.

Data on individual PCR efficiency values as quality control for circulating miRNAs

This data article contains data related to the research article entitled “Variability in microRNA recovery from plasma: Comparison of five commercial kits, doi:10.1016/j.ab.2015.07.018” Brunet-Vega (2015) [1]. PCR efficiency, along with RNA and cDNA quality, are the most important factors affecting the quality of qPCR results. Constant amplification efficiency in all compared samples is indispensable when relative quantification is used to measure changes in gene expression. An easy way to measure PCR efficiency, without the need of a standard curve, is LinRegPCR software. Individual PCR efficiency can be determined as a part of qPCR quality control. This is especially important when the initial RNA quantity is so low that cannot be accurately quantified, such as in circulating RNA extractions. This data article reports the Cqs and PCR efficiencies of 5 miRNAs quantified in RNA isolated from 4 patients with colorectal cancer (CRC) and 4 healthy donors using five commercially available kits.

Breast cancer circulating biomarkers: advantages, drawbacks, and new insights

As of today, the level of individualization of cancer therapies has reached a level that 20 years ago would be considered visionary. However, most of the diagnostic, prognostic, and therapy-predictive procedures which aim to improve the overall level of personalization are based on the evaluation of tumor tissue samples, therefore requiring surgical operations with consequent low compliance for patients and high costs for the hospital. Hence, the research of a panel of circulating indicators which may serve as source of information about tumor characteristics and which may be obtainable by a simple withdrawal of peripheral blood today represents a growing field of interest. This review aims to objectively summarize the characteristics of the currently available breast cancer circulating biomarkers, also providing an overview about the multitude of novel potential soluble predictors which are still under evaluation. Specifically, the usefulness of a so-called "liquid biopsy" will be discussed in terms of improvements of diagnosis, prognosis, and therapy-prediction, but an overview will be given also on the potentiality of the molecular characterization arising from the isolation of circulating biomarkers and cells. Although this review will focus on the specific case of the breast, in the future liquid biopsies will hopefully be available for virtually any type of neoplasms.

A microarray platform for detecting disease-specific circulating miRNA in human serum

Circulating microRNAs (miRNAs) are emerging as potential blood-based biomarkers for cancer and other critical diseases. To profile the expression levels of these tiny molecules, especially in a point-of-care setting, it is imperative to quantify them directly in complex biological fluids. Herein, we report the development of a microarray platform with carboxyl-polyethylene glycol (PEG) as a functional layer and aminated hairpin nucleic acid molecules as target-specific capture probes (CPs). Due to the anti-fouling effect conferred by the carboxyl-PEG layer, we could directly detect as little as 10fM of miRNA targets in 20µl of unprocessed human serum. In contrast to the conventional miRNA microarrays, our platform does not require RNA extraction, labeling and target amplification, thus significantly reducing both the sample preparation steps as well as the total assay duration. The use of specially designed hairpin CPs entails reliable discrimination of miRNA sequences with high sequence homology. A nanoparticle-based detection technique, with the help of differential interference contrast (DIC) microscopy, offers excellent resolution down to a single molecule. With the capability of detecting disease-specific miRNA targets directly in human serum, our microarray platform has potential applications in rapid, minimally invasive clinical diagnostic assays.