miRNAs as molecular biomarkers of cancer

Biomarkers in Laryngeal Squamous Cell Carcinoma: The Literature Review

Laryngeal squamous cell carcinoma (LSCC) is the second most common cancer among head and neck cancers. Despite a lower incidence of laryngeal carcinoma, new diagnostic techniques, and more targeted therapies, the overall survival has not changed significantly in the last decades, leading to a negative prognosis in advanced stages. Recently, several studies have focused on the identification of biomarkers that may play a critical role in the pathogenesis of LSCC. Reviewing the literature on the main databases, this study aims to investigate the role of some biomarkers in LSCC that are correlated with oxidative stress and inflammation: heat shock proteins; metallothioneins; nuclear factor erythroid 2-related factor 2; heme oxygenase; cyclooxygenase-2; and micro ribonucleic acids. This review shows that biomarker expression depends on the type, grade of differentiation, stage, and site of carcinoma. In addition, the role of these biomarkers in LSCC is still little-known and little-studied. However, the study of biomarker expression and the detection of a possible correlation with patients' epidemiological, clinicopathological, and therapeutics data may lead to better awareness and knowledge of the tumor, to the identification of the best therapeutic strategy, and the most proper follow-up protocol tailored for each patient. In conclusion, the achievement of these goals may improve the prognosis of LSCC patients.

MiR-223 Promotes Tumor Progression via Targeting RhoB in Gastric Cancer

Gastric cancer (GC) is among the most prevalent causes of cancer-related death globally. MiR-223 has been implicated in a variety of cellular mechanisms linked to cancer progression. However, the miR-223 expressions and its function in GC are unknown. We discovered that miR-223 expression was raised in GC tissues in comparison with nearby normal tissues in this investigation. Additionally, multiplied miR-223 expression was strongly linked with TNM stage (p=0.022), live metastasis (p=0.004),lymph node metastasis (p=0.004),and Borrmann type and was associated with an unfavorable prognostic for patients with GC. Furthermore, suppressing miR-223 significantly increased cell death and prevented cell migration and invasion in vitro. Additionally, miR-223 silencing decreased tumor development in vivo. Additionally, we discovered that miR-223 enhanced GC development by specifically targeting RhoB. In summary, our findings reveal that miR-223 increases tumor progression in GC by targeting RhoB, suggesting that it could serve to be a potential biomarker for the prediction of the disease.

MicroRNA-16 Restores Sensitivity to Tyrosine Kinase Inhibitors and Outperforms MEK Inhibitors in KRAS-Mutated Non-Small Cell Lung Cancer

BACKGROUND

Non-small cell lung cancer (NSCLC) is the leading cause of cancer death worldwide. Chemotherapy, the treatment of choice in non-operable cases, achieves a dismal success rate, raising the need for new therapeutic options. In about 25% of NSCLC, the activating mutations of the KRAS oncogene define a subclass that cannot benefit from tyrosine kinase inhibitors (TKIs). The tumor suppressor miR-16 is downregulated in many human cancers, including NSCLC. The main objectives of this study were to evaluate miR-16 treatment to restore the TKI sensitivity and compare its efficacy to MEK inhibitors in KRAS-mutated NSCLC.

METHODS

We performed in vitro and in vivo studies to investigate whether miR-16 could be exploited to overcome TKI resistance in KRAS-mutated NSCLC. We had three goals: first, to identify the KRAS downstream effectors targeted by mir-16, second, to study the effects of miR-16 restoration on TKI resistance in KRAS-mutated NSCLC both in vitro and in vivo, and finally, to compare miR-16 and the MEK inhibitor selumetinib in reducing KRAS-mutated NSCLC growth in vitro and in vivo.

RESULTS

We demonstrated that miR-16 directly targets the three KRAS downstream effectors MAPK3, MAP2K1, and CRAF in NSCLC, restoring the sensitivity to erlotinib in KRAS-mutated NSCLC both in vitro and in vivo. We also provided evidence that the miR-16-erlotinib regimen is more effective than the selumetinib-erlotinib combination in KRAS-mutated NSCLC.

CONCLUSIONS

Our findings support the biological preclinical rationale for using miR-16 in combination with erlotinib in the treatment of NSCLC with KRAS-activating mutations.

Identification of Prognostic and Chemopredictive microRNAs for Non-Small-Cell Lung Cancer by Integrating SEER-Medicare Data

This study developed a novel methodology to correlate genome-scale microRNA (miRNA) expression profiles in a lung squamous cell carcinoma (LUSC) cohort (n = 57) with Surveillance, Epidemiology, and End Results (SEER)-Medicare LUSC patients (n = 33,897) as a function of composite tumor progression indicators of T, N, and M cancer stage and tumor grade. The selected prognostic and chemopredictive miRNAs were extensively validated with miRNA expression profiles of non-small-cell lung cancer (NSCLC) patient samples collected from US hospitals (n = 156) and public consortia including NCI-60, The Cancer Genome Atlas (TCGA; n = 1016), and Cancer Cell Line Encyclopedia (CCLE; n = 117). Hsa-miR-142-3p was associated with good prognosis and chemosensitivity in all the studied datasets. Hsa-miRNA-142-3p target genes (NUP205, RAN, CSE1L, SNRPD1, RPS11, SF3B1, COPA, ARCN1, and SNRNP200) had a significant impact on proliferation in 100% of the tested NSCLC cell lines in CRISPR-Cas9 (n = 78) and RNA interference (RNAi) screening (n = 92). Hsa-miR-142-3p-mediated pathways and functional networks in NSCLC short-term survivors were elucidated. Overall, the approach integrating SEER-Medicare data with comprehensive external validation can identify miRNAs with consistent expression patterns in tumor progression, with potential implications for prognosis and prediction of chemoresponse in large NSCLC patient populations.

Epigenetic alterations in the gastrointestinal tract: Current and emerging use for biomarkers of cancer

Colorectal cancer is a leading cause of cancer related deaths worldwide. One of the hallmarks of cancer and a fundamental trait of virtually all gastrointestinal cancers is genomic and epigenomic DNA alterations. Cancer cells acquire genetic and epigenetic alterations that drive the initiation and progression of the cancers by altering the molecular and cell biological process of the cells. These alterations, as well as other host and microenvironment factors, ultimately mediate the initiation and progression of cancers, including colorectal cancer. Epigenetic alterations, which include changes affecting DNA methylation, histone modifications, chromatin structure, and noncoding RNA expression, have emerged as a major class of molecular alteration in colon polyps and colorectal cancer. The classes of epigenetic alterations, their status in colorectal polyps and cancer, their effects on neoplasm biology, and their application to clinical care will be discussed.

Comparison of miRNA expressions among benign, premalignant and malignant lesions of the larynx: could they be transformation biomarkers?

Background

The malignancy potential of the laryngeal lesions are one of the major concerns of the surgeons about choosing the treatment options, forming surgical margins, deciding the follow-up periods. Finding a biomarker to overcome these concerns are ongoing challenges and recently microRNAs (miRNAs) are attributed as possible candidates since they can regulate gene expressions in the human genome. The objective of our study was to investigate their capability as a transformation biomarker for malignant laryngeal lesions.

Materials and methods

We investigated mature miRNA expressions in paraffin-embedded surgical specimens of human laryngeal tissues grouped as benign, premalignant or malignant (n = 10 in each). miRNA profiling was carried out by quantitative Real-Time polymerase chain reaction (RT-qPCR) and data were analyzed according to fold regulation.

Results

Our results demonstrated that 9 miRNAs were upregulated as the lesions become more malignant. Among them Hs_miR-183_5p, Hs_miR-155_5p, and Hs_miR-106b_3p expressions were significantly 4.16 (p = 0.032), 2.72 (p = 0.028) and 3.01 (p = 0.022) fold upregulated respectively in premalignant lesions compared to the benign lesions. Moreover, their expressions were approximately 2.76 fold higher in the malignant group than in the premalignant group compared to the benign group. Besides them, significant 7.57 (p = 0.036), 4.45 (p = 0.045) and 5.98 (p = 0.023) fold upregulations of Hs_miR-21_5p, Hs_miR-218_3p, and Hs_miR-210_3p were noticed in the malignant group but not in the premalignant group when compared to the benign group, respectively.

Conclusion

MiRNAs might have important value to help the clinicians for their concerns about the malignancy potentials of the laryngeal lesions. Hs_miR-183_5p, Hs_miR-155_5p, and Hs_miR-106b_3p might be followed as transformation marker, whereas Hs_miR-21_5p, Hs_miR-218_3p, and Hs_miR-210_3p might be a biomarker prone to malignancy.

Androgen receptor (AR) decreases HCC cells migration and invasion via miR-325/ACP5 signaling

Hepatocellular carcinoma (HCC) is the most 5th commonly diagnosed and 2nd most lethal tumor in the world. The obvious gender advantage of HCC indicates that androgen receptor (AR) may play an important role in the tumor occurrence, develop and metastasis of HCC. Here we found that decreased AR could alter miR-325 to increase ACP5 expression in HCC cells, to increase HCC cells migration and invasion capacities. Mechanism dissection revealed that AR could regulate miR-325 expression through transcriptional regulation and miR-325 might directly target the 3'UTR of ACP5-mRNA to suppress its translation. The in vivo orthotopic xenografts mouse model with oemiR-325 also validated in vitro data. Together, these findings suggest that AR may decrease HCC progression through miR-325/ACP5 signaling and targeting the AR/miR-325/ACP5 signaling may help in the development of the novel therapies to better suppress the HCC progression.

Effects of miR-218-1-3p and miR-149 on proliferation and apoptosis of non-small cell lung cancer cells

The aim of the present study was to explore the effects of miR-218-1-3p and miR-149 on the biological function of non-small cell lung cancer (NSCLC) cells A549. Paired NSCLC and adjacent tissues were obtained from 50 NSCLC patients admitted to Shandong Provincial Chest Hospital Affiliated to Shandong University (Jinan, China) from April 2015 to May 2018. The expression levels of miR-218-1-3p and miR-149 were detected by reverse transcription-quantitative PCR (RT-qPCR). The lung adenocarcinoma A549 cells were assigned into the blank group (without transfection), negative control (NC) group (transfected with miRNA NC), and the transfected groups miR-218-1-3p mimic and miR-149 mimic groups. Proliferation and cell growth were determined by CCK-8 assay and cell invasion ability in vitro was assessed by Transwell assay. Flow cytometry was carried out for the detection of cell apoptosis. RT-qPCR results showed that the expression levels of miR-218-1-3p and miR-149 in NSCLC tissues were significantly lower than those in adjacent tissues (P<0.001). At 48 and 72 h, the cell growth of the A549 cells in the miR-218-1-3p mimic and miR-149 mimic groups was significantly lower than that in the NC and blank groups (P<0.05). The number of invasive cells in the miR-218-1-3p mimic and miR-149 mimic groups was significantly lower than that in the NC and blank groups (P<0.05). The apoptotic rate of A549 cells in the miR-218-1-3p mimic and miR-149 mimic groups was significantly higher than that in the NC and blank groups (P<0.05). In conclusion, upregulation of miR-218-1-3p and miR-149 can inhibit the proliferation, invasion and migration of A549 cells in NSCLC, thereby promoting the apoptosis of A549 cells. Thus, miR-218-1-3p and miR-149 can be used as new molecular targets for the diagnosis and treatment of NSCLC.

Identification of Circulating MicroRNAs as a Promising Diagnostic Biomarker for Cervical Intraepithelial Neoplasia and Early Cancer: A Meta-Analysis

Background

Cervical cancer (CC) is one of the most common female malignant tumors. And cervical intraepithelial neoplasia (CIN) is the precancerous lesion of CC, which can progress to invasive CC. MicroRNAs (miRNAs) have been found to be potential diagnostic biomarkers for CIN or CC. However, recently, the lack of sufficient studies about the diagnostic value of miRNAs for CIN made it challenging to separately investigate the diagnostic efficacy of miRNAs for CIN. Likewise, the conclusions among those studies were discordant. Therefore, we conducted this meta-analysis, aimed at evaluating the diagnostic efficacy of miRNAs for CIN and CC patients.

Methods

Literature search was performed in PubMed, Embase, and Web of Science databases. Pooled sensitivity, specificity, and other diagnostic parameters were calculated through Stata 14.0 software. Furthermore, subgroup analyses and metaregression analysis were conducted to explore the main sources of heterogeneity.

Results

Ten articles covering 50 studies were eligible, which included 5,908 patients and 4,819 healthy individuals. The pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under the curve (AUC) were 0.81 (95% CI, 0.77-0.85), 0.86 (95% CI, 0.83-0.89), 5.9 (95% CI, 4.5-7.7), 0.22 (95% CI, 0.17-0.28), 27 (95% CI, 17-44), and 0.91 (95% CI, 0.88-0.93), respectively. Additionally, the ethnicity and internal reference were the main sources of heterogeneity.

Conclusions

Circulating miRNAs can be a promising noninvasive diagnostic biomarker for CIN and early CC, especially miR-9 and miR-205, which need to be verified by large-scale studies.

Upregulation of miR-489-3p and miR-630 inhibits oxaliplatin uptake in renal cell carcinoma by targeting OCT2

Renal cell carcinoma (RCC) is one of the most common malignant tumors affecting the urogenital system, accounting for 90% of renal malignancies. Traditional chemotherapy options are often the front-line choice of regimen in the treatment of patients with RCC, but responses may be modest or limited due to resistance of the tumor to anticarcinogen. Downregulated expression of organic cation transporter OCT2 is a possible mechanism underlying oxaliplatin resistance in RCC treatment. In this study, we observed that miR-489-3p and miR-630 suppress OCT2 expression by directly binding to the OCT2 3'-UTR. Meanwhile, via 786-O-OCT2-miRNAs stable expression cell models, we found that miRNAs could repress the classic substrate 1-methyl-4-phenylpyridinium (MPP⁺), fluorogenic substrate N,N-dimethyl-4-(2-pyridin-4-ylethenyl) aniline (ASP⁺), and oxaliplatin uptake by OCT2 both in vitro and in xenografts. In 33 clinical samples, miR-489-3p and miR-630 were significantly upregulated in RCC, negatively correlating with the OCT2 expression level compared to that in adjacent normal tissues, using tissue microarray analysis and qPCR validation. The increased binding of c-Myc to the promoter of pri-miR-630, responsible for the upregulation of miR-630 in RCC, was further evidenced by chromatin immunoprecipitation and dual-luciferase reporter assay. Overall, this study indicated that miR-489-3p and miR-630 function as oncotherapy-obstructing microRNAs by directly targeting OCT2 in RCC.

Epigenetics and Common Non Communicable Disease

Common Non communicable diseases (NCDs), such as cardiovascular disease, cancer, schizophrenia, and diabetes, have become the major cause of death in the world. They result from an interaction between genetics, lifestyle and environmental factors. The prevalence of NCDs are increasing, and researchers hopes to find efficient strategies to predict, prevent and treat them. Given the role of epigenome in the etiology of NCDs, insight into epigenetic mechanisms may offer opportunities to predict, detect, and prevent disease long before its clinical onset.Epigenetic alterations are exerted through several mechanisms including: chromatin modification, DNA methylation and controlling gene expression by non-coding RNAs (ncRNAs). In this chapter, we will discuss about NCDs, with focus on cancer, diabetes and schizophrenia. Different epigenetic mechanisms, categorized into two main groups DNA methylation and chromatin modifications and non-coding RNAs, will be separately discussed for these NCDs.

MicroRNA-195 as a diagnostic biomarker in human cancer detection: A meta-analysis

MicroRNAs (miRNAs/miRs) show great promise as novel cancer biomarkers. Several studies have revealed an association between abnormal miRNA expression and the risk of various cancer types. However, the diagnostic accuracy and reliability of miRNAs remains unclear. The present meta-analysis was performed to summarize the overall diagnostic performance of miR-195 for cancer. The PubMed, Cochrane Library, Wanfang and China National Knowledge Infrastructure databases were searched for associated literature published until December 10, 2017. Eligible studies were selected using multiple search strategies based on study selection criteria. Measures, including sensitivity and specificity, of the performance of miR-195 as a cancer diagnostic tool were pooled using bivariate meta-analysis models. All analyses were performed using Stata 14.0. The pooled analysis included 8 studies comprising 735 cases and 547 controls. The pooled diagnostic results calculated from all studies were as follows: Sensitivity, 0.79 [95% confidence interval (CI), 0.69–0.87]; specificity, 0.84 (95% CI, 0.68–0.93); positive likelihood ratio, 4.9 (95% CI, 2.50–9.50); negative likelihood ratio, 0.25 (95% CI, 0.18–0.35); diagnostic odds ratio, 20 (95% CI, 10.00–38.00); and area under the curve, 0.87 (95% CI, 0.84–0.90). Deeks' funnel plot asymmetry test suggested no potential publication bias (P=0.53). The present meta-analysis indicated that miR-195 could be a reliable non-invasive biomarker for the diagnosis of cancer. Further large-scale prospective studies are necessary to confirm the present findings and the clinical value of miR-195 for future diagnostics.

Small Nucleolar RNA Score: An Assay to Detect Formalin-Overfixed Tissue

Although there are millions of formalin-fixed paraffin-embedded (FFPE) tissue blocks potentially available for scientific research, many are of questionable quality, partly due to unknown fixation conditions. We analyzed FFPE tissue biospecimens as part of the NCI Biospecimen Preanalytical Variables (BPV) program to identify microRNA (miRNA) markers for fixation time. miRNA was extracted from kidney and ovary tumor FFPE blocks (19 patients, cold ischemia ≤2 hours) with 6, 12, 24, and 72 hours fixation times, then analyzed using the WaferGen SmartChip platform (miRNA chip with 1036 miRNA targets). For fixation time, principal component analysis of miRNA chip expression data separated 72 hours fixed samples from 6 to 24 hours fixed samples. A set of small nuclear RNA (snRNA) targets was identified that best determines fixation time and was validated using a second independent cohort of seven different tissue types. A customized assay was then developed, based on a set of 24 miRNA and snRNA targets, and a simple “snoRNA score” defined. This score detects FFPE tissue samples with fixation for 72 hours or more, with 79% sensitivity and 80% specificity. It can therefore be used to assess the fitness-for-purpose of FFPE samples for DNA or RNA-based research or clinical assays, which are known to be of limited robustness to formalin overfixation.

miRNAs in platelet-poor blood plasma and purified RNA are highly stable: a confirmatory study

Objective

We wished to re-assess the relative stability of microRNAs (miRNAs) as compared with other RNA molecules, which has been confirmed in many contexts. When bound to Argonaute proteins, miRNAs are protected from degradation, even when released into the extracellular space in ribonucleoprotein complexes, and with or without the protection of membranes in extracellular vesicles. Purified miRNAs also appear to present less of a target for degradation than other RNAs. Although miRNAs are by no means immune to degradation, biological samples subjected to prolonged incubation at room temperature, multiple freeze/thaws, or collection in the presence of inhibitors like heparin, can typically be remediated or used directly for miRNA measurements.

Results

Here, we provide additional confirmation of early, well validated findings on miRNA stability and detectability. Our data also suggest that inadequate depletion of platelets from plasma may explain the occasional report that freeze–thaw cycles can adversely affect plasma miRNA levels. Overall, the repeated observation of miRNA stability is again confirmed.

IIKmTA: Inter and Intra Kingdom miRNA-Target Analyzer

BACKGROUND

Growing evidences suggest that microRNAs (miRNAs) can efficiently regulate gene expression at intracellular and extracellular levels. It has been previously reported that plant/food-derived miRNAs are highly enriched in human serum or serum from phytophagous animals, and they are responsible for regulating mammalian gene expression. Thus, miRNAs could function as active signaling molecules, which carry information across distinct species or even kingdoms. However, the mode of miRNA shuttling among various organisms is still a mystery to unravel. The intra and inter kingdom miRNA transfer has boosted up the hypothesis about the potential impact of plant or animal miRNAs on each other. To our knowledge, the software for analyzing cross-kingdom miRNA-targets is lacking.

RESULTS

We have developed a web-tool "IIKmTA: Inter and Intra Kingdom miRNA-Target Analyzer" utilizing a database; the data of which have been collected from another web server. Here, user can analyze the targeting potential of (i) plant miRNAs on animal UTRs (Untranslated regions), and vice versa (i.e., inter kingdom), (ii) plant miRNAs on plant UTRs and animal miRNAs on animal UTRs (i.e., intra kingdom). Further, user can analyze (i) miRNAs to targets, (ii) targets to miRNAs, and (iii) miRNA sets targeting sets of targets. For a wide variety of animal and plant species, IIKmTA can identify the miRNA binding sites in the probable target UTRs. Moreover, GC% and AU% of miRNAs will be calculated. All the results can be saved as .csv file.

CONCLUSIONS

Recent researches identified miRNAs in plants and human secretions and their role in regulating the human genes. Such findings indicate the therapeutic role of secretory miRNAs of such plants which exhibits medicinal value and in near future many diseases may be treated by consumption of these plant miRNAs through food. Using our newly developed database and analyzing tool, one can easily determine the different relationships between miRNAs and their targets across kingdoms. IIKmTA is freely available at http://www.bioinformatics.org/iikmta/ .

Upregulation of miR-146a increases cisplatin sensitivity of the non-small cell lung cancer A549 cell line by targeting JNK-2

The aim of the present study was to investigate the effects of microRNA (miR-)146a on the cisplatin sensitivity of the non-small cell lung cancer (NSCLC) A549 cell line and study the underlying molecular mechanism. The differences in expression of miRNAs between A549 and A549/cisplatin (A549/DDP) cells were determined, and miR-146a was selected to study its effect on cisplatin sensitivity of A549/DDP cells. miR-146a mimic and inhibitor transient transfection systems were constructed using vectors, and A549/DDP cells were infected with miR-146a mimic and inhibitor to investigate growth, apoptosis and migration. The directed target of miR-146a was determined and the underlying molecular mechanism was validated in the present study. The results of the present study demonstrated that miR-146a was downregulated in NSCLC A549/DDP cells, compared with A549 cells. The overexpression of miR-146a induced apoptosis and inhibited the growth and invasion of A549/DDP cells, which resulted in increased cisplatin sensitivity in NSCLC cells. The JNK2 gene was determined as the direct target of miR-146a, and may be activated by the overexpression of miR-146a. Additionally, JNK2 activated the expression of p53 and inhibited B cell lymphoma 2. The upregulation of miR-146a increased cisplatin sensitivity of the A549 cell line by targeting JNK2, which may provide a novel method for treating NSCLC cisplatin resistance.

Correlation between the DNA methylation and gene expression of IGFBP5 in breast cancer

BACKGROUND

The insulin-like growth factor binding protein5 (IGFBP5) is often dysregulated in human cancers and considered neither a tumor suppressor nor an oncogene.

OBJECTIVE

We aim to examine the reason of the changeable gene regulation of IGFBP5 in the case of methylation in breast cancer.

METHODS

We used methyl-specific polymerase (MSP) chain reaction to detect CpG methylation of IGFBP5 promoter and exon-I in breast cancer and adjacent tissues. Gene expression is evaluated by quantative polymerase chain reaction (qPCR).

RESULTS

IGFBP5 methylation was detected in 24 of 58 (41%) and 54 of 56 (96.5%) promoter and exon-I site respectively in tumor tissues. In adjacent tissues 17 of 58 (29%) and 53 of 56 (96.5%) was methylated. IGFBP5 expression was higher estrogene receptor (ER)(+) than ER(-) patients (p = 0.0549). Beside, we found a positive correlation between the expression of IGFBP5 and G2 tumor grade (p = 0.0131). However, no correlation was observed between IGFBP5 expression and age, menopause or the presence of lymph node metastasis (p > 0.05).

CONCLUSIONS

In summary, our results showed that IGFBP5 promoter and exon-I methylation did not have any differences between tumor and adjacent tissues so that IGFBP5 methylation did not change IGFBP5 gene regulation in breast cancer. This is the first study investigating the IGFBP5 gene methylation in breast cancer.

Bioinformatics analysis of dysregulated microRNAs in the nipple discharge of patients with breast cancer

MicroRNAs (miRNAs/miRs) have been reported to be associated with the tumorigenesis and progression of various types of human cancer; however, the underlying mechanisms of this association remain unclear. The aim of the present study was to explore the potential functions of miRNAs in the development of breast cancer using bioinformatics analysis, based on the miRNA expression profile in nipple discharge. A previous study demonstrated the upregulation of miR-3646 and miR-4484, and the downregulation of miR-4732-5p in the nipple discharge of patients with breast cancer, compared with patients with benign breast lesions. In the present study, the target genes of miR-3646, −4484 and −4732-5p were predicted using TargetScan and the MicroRNA Target Prediction and Functional Study Database. The predicted target genes were further analyzed by Gene Ontology term enrichment analysis, Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis and protein-protein interaction analysis. Numerous carcinoma-associated genes, including ADIPOQ, CPEB1, DNAJB4, EIF4E, APP and BCLAF1, were revealed to be putative targets of miR-3646, −4484 and −4732-5p. Bioinformatics analysis associated miR-3646 with the Rap1 and TGF-β signaling pathways, miR-4484 with the ErbB, estrogen and focal adhesion signaling pathways, and miR-4732-5p with the proteoglycan signaling pathway. Notably, protein-protein interaction analysis identified that numerous predicted targets of these miRNAs were associated with one other. In addition, the target genes of the miRNAs were identified to be under the regulation of a number of transcription factors (TFs). The predicted target genes of miR-3646, −4484 and −4732-5p were identified to serve a role in cancer-associated signaling pathways and TF-mRNA networks, indicating that they serve a role in breast carcinogenesis and progression. These results provide a comprehensive view of the functions and molecular mechanisms of miR-3646, −4484 and −4732-5p, and will aid in future studies.

Circulating microRNA-203 predicts metastases, early recurrence, and poor prognosis in human gastric cancer

BACKGROUND

Metastasis is a major cause of death in patients with gastric cancer (GC). MicroRNAs (miRNAs) relating to the epithelial-mesenchymal transition (EMT) control GC progression and metastasis. The aim of this study was to evaluate serum EMT-associated miRNAs for metastatic and prognostic noninvasive biomarkers in GC.

METHODS

In the first step of this study (preliminary experiments), we selected candidate miRNAs associated with metastasis by analyzing the expression of the miR-200 family (miR-200a, miR-200b, miR-200c, miR-141, and miR-429) and miR-203 in serum samples from stage I (n = 12) and stage IV (n = 12) GC patients. The second phase involved the independent validation of candidate miRNAs in serum specimens from 130 patients with GC and 22 controls.

RESULTS

Based on the preliminary experiments, miR-203 was selected as the candidate serum miRNA that was most closely associated with metastasis. Validation analysis revealed that serum miR-203 levels were significantly lower in stage IV than stage I-III GC patients. Serum miR-203 expression was significantly lower in GC patients with a higher T stage, vessel invasion, and lymph node, peritoneal, and distant metastases. Low expression of serum miR-203 was significantly associated with poor disease-free and overall survival. Multivariate analysis revealed that low serum miR-203 expression was an independent predictive marker for lymph node, peritoneal, and distant metastases and a poor prognosis in patients with GC.

CONCLUSIONS

Serum miR-203 has the potential to serve as a noninvasive biomarker for prognosis and to predict metastasis in patients with GC.

miR-101-2, miR-125b-2 and miR-451a act as potential tumor suppressors in gastric cancer through regulation of the PI3K/AKT/mTOR pathway

BACKGROUND

Gastric cancer (GC) is a deadly malignancy worldwide. In the past, it has been shown that cellular signaling pathway alterations play a crucial role in the development of GC. In particular, deregulation of the PI3K/AKT/mTOR pathway seems to affect multiple GC functions including growth, proliferation, metabolism, motility and angiogenesis. Targeting alterations in this pathway by microRNAs (miRNAs) represents a potential therapeutic strategy, especially in inhibitor-resistant tumors. The objective of this study was to evaluate the expression of 3 pre-selected miRNAs, miR-101-2, miR-125b-2 and miR-451a, in a series of primary GC tissues and matched non-GC tissues and in several GC-derived cell lines, and to subsequently evaluate the functional role of these miRNAs.

METHODS

Twenty-five primary GC samples, 25 matched non-GC samples and 3 GC-derived cell lines, i.e., AGS, MKN28 and MKN45, were included in this study. miRNA and target gene expression levels were assessed by quantitative RT-PCR and western blotting, respectively. Subsequently, cell viability, clone formation, cell death, migration and invasion assays were performed on AGS cells.

RESULTS

miR-101-2, miR-125b-2 and miR-451a were found to be down-regulated in the primary GC tissues and the GC-derived cell lines tested. MiRNA mimic transfections significantly reduced cell viability and colony formation, increased cell death and reduced cell migration and invasion in AGS cells. We also found that exogenous expression of miR-101-2, miR-125b-2 and miR-451a decreased the expression of their putative targets MTOR, PIK3CB and TSC1, respectively.

CONCLUSIONS

Our expression analyses and in vitro functional assays suggest that miR-101-2, miR-125b-2 and miR-451a act as potential tumor suppressors in primary GCs as well as in GC-derived AGS cells.

Overexpression of MicroRNA-221 is associated with poor prognosis in non-small cell lung cancer patients

The abnormal expression of microRNA-221 was detected in several cancers and some studies had indicated that microRNA-221 was associated with cancer prognosis. This study was aimed to evaluate the prognostic significance of microRNA-221 in non-small cell lung cancer (NSCLC). Quantitative real-time polymerase chain reaction (qRT-PCR) was used for detecting the relative expression levels of microRNA-221 in the pathological tissues and corresponding normal tissues of 104 NSCLC patients. The relationship between the expression levels and the clinical features was estimated by Chi-square method and the overall survival of patients at different expression levels was demonstrated by Kaplan-Meier method. Cox regression analysis was used to evaluate the prognostic significance of microRNA-221. The relative expression levels of microRNA-221 in the pathological tissues were remarkably higher than that in the corresponding normal tissues (1.71 vs 1.07, P = 0.000). The expression level was associated with lymph node metastasis (P = 0.001). The results of Kaplan-Meier method indicated that patients with high expression level of microRNA-221 had shorter overall survival time than those with low expression level (36.8 vs 45.2 months, P = 0.001). Moreover, Cox regression analysis suggested that microRNA-221 was a useful independent biomarker for NSCLC prognosis (HR = 1.873, 95 % CI = 1.267-2.768, P = 0.002). The aberrant expression of microRNA-221 is associated with NSCLC progression and it might be a potential biomarker for NSCLC prognosis.

Circulating cell-free microRNAs as biomarkers for colorectal cancer

MicroRNAs (miRNAs) are a class of small, endogenous, non-coding, single-stranded RNAs that act as post-transcriptional regulators. Their discovery has provided new avenues for the diagnosis and treatment of cancer. The expression of both oncogenic and tumor suppressor miRNAs can be aberrantly either up- or down-regulated in cancer cells. These miRNAs target mRNAs of genes that either promote or inhibit tumor growth, and are one of several epigenetic factors that control the initiation and progression of colorectal cancer (CRC) and other cancers. Investigations of miRNAs as CRC biomarkers have employed the expression profiling of traditional tissue samples and, more recently, non-invasive samples, such as feces and body fluids, have been analyzed. MiRNAs may also be able to predict responses to chemo- and radiotherapy, and may be manipulated to modify CRC characteristics. We herein discuss the use of circulating miRNAs as possible non-invasive biomarkers of early CRC onset, relapse, or response to treatment. We also discuss the obstacles that currently limit the routine use of epigenetic biomarkers in clinical settings.

MicroRNA-17 family as novel biomarkers for cancer diagnosis: a meta-analysis based on 19 articles

Cancer remains as the leading cause of death all over the world due to the lack of efficient diagnostic techniques and therapeutic methods. Many studies have reported the potential diagnostic value of microRNA-17 (miRNA-17, miR-17) family members as biomarkers for cancer detection. However, inconsistent results were revealed from a wide range of studies. As a result of this, a meta-analysis based on 19 studies was conducted to assess the diagnostic performance of miR-17 family for cancer detection. A total of 1772 patients with certain types of cancer and 1320 healthy controls were involved in these studies. The overall diagnostic accuracy was measured by the following: sensitivity, 0.67 (95 % confidence interval (CI) 0.60-0.74); specificity, 0.83 (95 % CI 0.74-0.85); positive likelihood ratio (PLR), 3.9 (95 % CI 2.6-5.9); negative likelihood ratio (NLR), 0.40 (95 % CI 0.34-0.48); and diagnostic odds ratio (DOR), 10 (95 % CI 6-16), respectively. Additionally, the pooled area under the summary receiver operator characteristic (SROC) curve (area under the curve (AUC)) was 0.79 (95 % CI 0.75-0.82), indicating a relatively low accuracy of miR-17 family as biomarkers for cancer detection. Subgroup analysis further showed that miR-17 family had more reliable performance in cancer diagnosis for Asian than that for Caucasian. Moreover, multiple miRNAs containing miR-17, -20a/b, and -93 reflected higher diagnostic accuracy than both miR-106a/b (single miRNA) and the overall miR-17 family assay. Therefore, appropriate combinations of miR-17 family may be used as non-invasive screening biomarkers for cancer, and it is necessary to carry out a large-scale population-based study to further assess the potential diagnostic value of miR-17 family.

Mini-review: emerging roles of microRNAs in the pathophysiology of renal diseases

MicroRNAs (miRNA) are endogenously produced short noncoding regulatory RNAs that can repress gene expression by posttranscriptional mechanisms. They can therefore influence both normal and pathological conditions in diverse biological systems. Several miRNAs have been detected in kidneys, where they have been found to be crucial for renal development and normal physiological functions as well as significant contributors to the pathogenesis of renal disorders such as diabetic nephropathy, acute kidney injury, lupus nephritis, polycystic kidney disease, and others, due to their effects on key genes involved in these disease processes. miRNAs have also emerged as novel biomarkers in these renal disorders. Due to increasing evidence of their actions in various kidney segments, in this mini-review we discuss the functional significance of altered miRNA expression during the development of renal pathologies and highlight emerging miRNA-based therapeutics and diagnostic strategies for early detection and treatment of kidney diseases.

Epithelial membrane protein 3 functions as an oncogene and is regulated by microRNA-765 in primary breast carcinoma

Epithelial membrane protein 3 (EMP3) is a transmembrane signaling molecule, which is important in the regulation of apoptosis, differentiation and invasion of cancer cells. However, the specific function and regulatory mechanism of EMP3 in primary breast carcinoma remain to be elucidated. In the present study, the mRNA and protein levels of EMP3 were observed to be upregulated in primary breast carcinoma tissues, compared with normal tissues. It was hypothesized that the overexpression of EMP3 was correlated with the downregulation of microRNA‑765 (miR‑765), an underexpressed miRNA in primary breast carcinoma tissues. Functional analysis demonstrated that EMP3 was regulated by miR‑765 through binding to its 3'untranslated region. In addition, the knockdown of EMP3 and miR‑765 had similar effects on the inhibition of proliferation and invasion in SK‑BR‑3 cells. These results provided novel insight into the regulatory mechanism of EMP3 in primary breast carcinoma.

MicroRNAs in diabetic nephropathy: functions, biomarkers, and therapeutic targets

MicroRNAs (miRNAs) are short noncoding RNAs that regulate gene expression by posttranscriptional and epigenetic mechanisms and thereby affect many cellular processes and disease states. Over 2,000 human mature miRNAs have been identified, and at least 60% of all human protein-coding genes are known to be regulated by miRNAs. MicroRNA biogenesis involves classical transcription regulation and processing by key ribonucleases, as well as other protein factors and epigenetic mechanisms. Diabetic nephropathy (DN), a severe microvascular complication frequently associated with diabetes mellitus, is a major cause of renal failure. Although several mechanisms of regulation of key renal genes implicated in DN pathogenesis have been identified, a greater understanding is needed to develop better treatment modalities. Recent studies show that miRNAs induced in renal cells in vivo and in vitro under diabetic conditions can promote the accumulation of extracellular matrix proteins related to fibrosis and glomerular dysfunction. In this review, we highlight the significance of the expression of miRNAs in various stages of DN and emerging approaches to exploit them as biomarkers for early detection or novel therapeutic targets to prevent progression of DN.

The microRNA-1246 promotes metastasis in non-small cell lung cancer by targeting cytoplasmic polyadenylation element-binding protein 4

Background

The microRNAs present a class of non-coding RNAs which are usually implicated in tumor biology. Recent report has unraveled that a novel member of microRNA family called miR-1246. However, the functional role and molecular mechanisms of miR-1246 in non-small cell lung cancer (NSCLC) is still elusive.

Methods

Using RT-PCR, luciferase reporter, mRNA microarrays, invasion and migration assays, we investigated the potential role of miR-1246 in the pathogenesis of NSCLC.

Results

In this study, we showed that miR-1246 markedly promoted NSCLC cell migration and invasion. Meanwhile, we found that cytoplasmic polyadenylation element binding protein 4 (CPEB4) might be involved and serve as a direct target of miR-1246 in NSCLC. CPEB4 knockdown substantially enhanced NSCLC migration and invasion resembling the effect of miR-1246 in NSCLC. CPEB4 is also frequently downregulated in NSCLC and decreased CPEB4 expression correlated with poor survival.

Conclusions

These results suggested that the miR-1246 may promote cell metastasis by targeting CPEB4. Meanwhile, the level of CPEB4 could be used as a potential marker in NSCLC patients. Our findings unraveled novel functions of miR-1246 in lung cancer cells and shed light on NSCLC prognosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13000-015-0366-1) contains supplementary material, which is available to authorized users.

The microRNA-325 inhibits hepatocellular carcinoma progression by targeting high mobility group box 1

Background

MicroRNAs (miRNAs) can serve as tumor suppressors and might provide an efficient strategy for annihilating tumor cells. Nevertheless, the potential role of miR-325 in hepatocellular carcinoma (HCC) is still unknown.

Methods

Using RT-PCR, immunoblots invasion assays and bioinformatics strategies, we investigated the potential role of miR-325 in HCC.

Results

We showed that miR-325 was decreased and HMGB1 was increased in 99 patients with hepatocellular carcinoma. MiR-325 inhibition promoted cell invasion and proliferation, while miR-325 upregulation inhibited cell invasion and proliferation by using transwell and CCK8 assays. We further showed that HMGB1 might be a direct target of miR-325 and is negatively regulated by miR-325. Down-regulation of miR-325 predicts poor prognosis for HCC patients.

Conclusions

These findings implied that miR-325 regulates cell invasion and proliferation via targeting HMGB1 and may be a potential prognostic marker for HCC.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/4655707031717989

Circulating miR-103 and miR-720 as novel serum biomarkers for patients with colorectal cancer

Circulating microRNAs (miRNAs) have been reported as a biomarker for human malignancies, including colorectal cancer (CRC). The purpose of this study was to identify a novel biomarker for CRC through examination of serum miRNAs from the patients with CRC. Microarray analysis of miRNA expression was performed using paired pre- and post-operative serum from 10 CRC patients. miR-103 and miR-720 decreased significantly in the post-operative serum when compared to pre-operative serum. With an extended scale validation by qRT-PCR (quantitative real-time polymerase chain reaction) in 30 CRC patients, we confirmed that serum miR-103 and miR-720 decreased significantly after surgery (P=0.0004, and P=0.0274, respectively). Next, we examined serum miR-103 and miR-720 levels in 32 non-cancer patients and 84 CRC patients, and we found that expression of these two miRNAs was significantly higher in CRC patients than non-cancer patients. Furthermore, clinical and pathological survey indicated that high expression of miR-103 was significantly associated with histological differentiation grade, and lymphatic invasion and high expression of miR-720 was significantly associated with male gender and lymph node metastasis. Our data suggest that circulating miR-103 and miR-720 show potential as novel serum biomarkers for CRC.

A Novel Label-Free microRNA-155 Detection on the Basis of Fluorescent Silver Nanoclusters

In this paper, a new approach for microRNA-155 (miRNA-155) detection was described based on the fluorescence quenching of oligonucleotide-templated silver nanoclusters (DNA-AgNCs). The specific DNA scaffold with two different nucleotides fragments were used: one was enriched with a cytosine sequence fragment (C12) that could result in DNA-AgNCs with a high quantum yield via a chemical reduction method, and the other was the probe fragment (5- CUGUUAAUGCUAAUCGUG-3) which could selectively bind to the miRNA-155. Thus, the as-prepared AgNCs could exhibit quenched fluorescence when binding to the target miRNA-155. The fluorescence ratio of the DNA-AgNCs was quenched in a linearly proportional manner to the concentration of the target in the range of 0.2 nM to 30 nM with a detection limit of 0.1 nM.

miR-638 is a new biomarker for outcome prediction of non-small cell lung cancer patients receiving chemotherapy

MicroRNAs (miRNAs), a class of small non-coding RNAs, mediate gene expression by either cleaving target mRNAs or inhibiting their translation. They have key roles in the tumorigenesis of several cancers, including non-small cell lung cancer (NSCLC). The aim of this study was to investigate the clinical significance of miR-638 in the evaluation of NSCLC patient prognosis in response to chemotherapy. First, we detected miR-638 expression levels in vitro in the culture supernatants of the NSCLC cell line SPC-A1 treated with cisplatin, as well as the apoptosis rates of SPC-A1. Second, serum miR-638 expression levels were detected in vivo by using nude mice xenograft models bearing SPC-A1 with and without cisplatin treatment. In the clinic, the serum miR-638 levels of 200 cases of NSCLC patients before and after chemotherapy were determined by quantitative real-time PCR, and the associations of clinicopathological features with miR-638 expression patterns after chemotherapy were analyzed. Our data helped in demonstrating that cisplatin induced apoptosis of the SPC-A1 cells in a dose- and time-dependent manner accompanied by increased miR-638 expression levels in the culture supernatants. In vivo data further revealed that cisplatin induced miR-638 upregulation in the serum derived from mice xenograft models, and in NSCLC patient sera, miR-638 expression patterns after chemotherapy significantly correlated with lymph node metastasis. Moreover, survival analyses revealed that patients who had increased miR-638 levels after chemotherapy showed significantly longer survival time than those who had decreased miR-638 levels. Our findings suggest that serum miR-638 levels are associated with the survival of NSCLC patients and may be considered a potential independent predictor for NSCLC prognosis.

[MiR-614 inhibited lung cancer cell invasion and proliferation via targeting PSA]

背景与目的

MicroRNAs（miRNAs）是一种非编码的小分子RNA，在肿瘤的发生发展过程中发挥着重要的作用，各种miRNAs对肺癌的作用及机制仍需进一步阐明。本研究探讨了miR-614对肺癌细胞增殖和侵袭的作用及机制。

方法

应用实时定量PCR检测miR-614在高低不同转移能力肺癌PGCL3和PGLH7细胞中的表达水平；脂质体2000介导分别转染miR-614类似物和抑制物入PGCL3和PGLH7细胞，应用Transwell实验检测miR-614对肺癌细胞侵袭的作用；应用CCK8实验和BrdU掺入实验检测miR-614对肺癌细胞增殖的作用；生物信息学软件预测miR-614潜在的靶基因，双荧光素酶报告基因验证miR-614是否作用于嘌呤霉素敏感性氨肽酶（puromycin-sensitive aminopeptidase, PSA）mRNA的3’UTR区预测靶位；Western blot检测PSA蛋白水平。

结果

miR-614在高转移肺癌细胞PGCL3中的表达水平明显低于其在低转移肺癌细胞PGLH7的表达水平；体外侵袭实验结果显示，miR-614可抑制肺癌细胞侵袭；细胞增殖实验结果显示，miR-614可抑制肺癌细胞增殖；miRanda软件预测并经双荧光素酶报告基因验证PSA是miR-614的靶基因；miR-614类似物可下调PSA蛋白表达，miR-614抑制物可上调PSA蛋白表达。

结论

miR-614过表达抑制了人肺癌细胞的侵袭和增殖能力，PSA是miR-614下游靶基因之一。

Expression of MicroRNA-325-3p and its potential functions by targeting HMGB1 in non-small cell lung cancer

MicroRNAs (miRNAs) can function as tumor suppressors and might provide an efficient strategy for annihilating cancer. Nevertheless, the potential role of miR-325-3p in NSCLC is still unknown. Here, we showed that miR-325-3p was decreased and HMGB1 was increased in 107 NSCLC patients. MiR-325-3p inhibition promoted cell invasion and proliferation, while miR-325-3p upregulation inhibited cell invasion and proliferation by using transwell and CCK8 assays. Using a bioinformatics method, we further showed that HMGB1 might be a direct target of miR-325-3p and is negatively regulated by miR-325-3p. Down-regulation of miR-325-3p predicts poor prognosis for NSCLC patients. These findings implied that miR-325-3p regulates cell invasion and proliferation via targeting HMGB1 and may be a potential prognostic marker for NSCLC.

MicroRNA-145 as ideal biomarker for the diagnosis of various carcinomas

Increasing evidences indicated that microRNAs (miRNAs) can serve as a noninvasive biomarker with a high sensitivity and specificity for the early diagnosis of various cancers, among which, microRNA-145 (miRNA-145, miR-145) was verified to have strong relationship to irregular apoptosis, thus making it useful in the early detection of cancers. However, contradictory results on its diagnostic accuracy and reliability are still existed in individual studies. Therefore, we conducted this meta-analysis of the relevant published literatures to systematically evaluate the diagnostic value of miR-145 in the prediction of cancers. The sensitivity and specificity of the included studies were used to construct the summary receiver operator characteristic (SROC) curve and calculate the area under the SROC curve (AUC). All analyses were performed using the STATA 12.0 software. Thirteen studies from nine articles were involved in our meta-analysis. The pooled parameters calculated from all studies are as follows: sensitivity, 0.71 (95% confidence interval (CI) 0.59-0.81); specificity, 0.75 (95% CI 0.66-0.83); positive likelihood ratio (PLR), 2.9 (95% CI 1.9-4.4); negative likelihood ratio (NLR), 0.38 (95% CI 0.25-0.58); and diagnostic odds ratio (DOR), 8 (95% CI 3-17). In addition, subgroup analyses based on ethnicity suggested that miR-145 as a biomarker on the detection of cancers for Caucasian population showed a higher sensitivity and specificity than for Asian population. In conclusion, the current meta-analysis showed that miR-145 holds a high accuracy in distinguishing cancer patients from healthy controls with noninvasiveness and high efficiency. However, large-scale prospective studies and additional improvements are urgently needed to confirm our findings and its utilization for routine clinical diagnosis in future.

MicroRNA as new tools for prostate cancer risk assessment and therapeutic intervention: results from clinical data set and patients' samples

Prostate cancer (PCa) is one of the leading causes of cancer-related death in men. Despite considerable advances in prostate cancer early detection and clinical management, validation of new biomarkers able to predict the natural history of tumor progression is still necessary in order to reduce overtreatment and to guide therapeutic decisions. MicroRNAs are endogenous noncoding RNAs which offer a fast fine-tuning and energy-saving mechanism for posttranscriptional control of protein expression. Growing evidence indicate that these RNAs are able to regulate basic cell functions and their aberrant expression has been significantly correlated with cancer development. Therefore, detection of microRNAs in tumor tissues and body fluids represents a new tool for early diagnosis and patient prognosis prediction. In this review, we summarize current knowledge about microRNA deregulation in prostate cancer mainly focusing on the different clinical aspects of the disease. We also highlight the potential roles of microRNAs in PCa management, while also discussing several current challenges and needed future research.

DNA methylation and microRNA biomarkers for noninvasive detection of gastric and colorectal cancer

Cancer initiation and progression is controlled by both genetic and epigenetic events. Epigenetics refers to the study of mechanisms that alter gene expression without permanently altering the DNA sequence. Epigenetic alterations are reversible and heritable, and include changes in histone modifications, DNA methylation, and non-coding RNA-mediated gene silencing. Disruption of epigenetic processes can lead to altered gene function and malignant cellular transformation. Aberrant epigenetic modifications occur at the earliest stages of neoplastic transformation and are now believed to be essential players in cancer initiation and progression. Recent advances in epigenetics have not only offered a deeper understanding of the underlying mechanism(s) of carcinogenesis, but have also allowed identification of clinically relevant putative biomarkers for the early detection, disease monitoring, prognosis and risk assessment of cancer patients. At this moment, DNA methylation and non-coding RNA including with microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) represent the largest body of available literature on epigenetic biomarkers with the highest potential for cancer diagnosis. Following identification of cell-free nucleic acids in systematic circulation, increasing evidence has demonstrated the potential of cell-free epigenetic biomarkers in the blood or other body fluids for cancer detection. In this article, we summarize the current state of knowledge on epigenetic biomarkers - primarily DNA methylation and non-coding RNAs - as potential substrates for cancer detection in gastric and colorectal cancer, the two most frequent cancers within the gastrointestinal tract. We also discuss the obstacles that have limited the routine use of epigenetic biomarkers in the clinical settings and provide our perspective on approaches that might help overcome these hurdles, so that these biomarkers can be readily developed for clinical management of cancer patients.

Diabetic nephropathy--emerging epigenetic mechanisms

Diabetic nephropathy (DN), a severe microvascular complication frequently associated with both type 1 and type 2 diabetes mellitus, is a leading cause of renal failure. The condition can also lead to accelerated cardiovascular disease and macrovascular complications. Currently available therapies have not been fully efficacious in the treatment of DN, suggesting that further understanding of the molecular mechanisms underlying the pathogenesis of DN is necessary for the improved management of this disease. Although key signal transduction and gene regulation mechanisms have been identified, especially those related to the effects of hyperglycaemia, transforming growth factor β1 and angiotensin II, progress in functional genomics, high-throughput sequencing technology, epigenetics and systems biology approaches have greatly expanded our knowledge and uncovered new molecular mechanisms and factors involved in DN. These mechanisms include DNA methylation, chromatin histone modifications, novel transcripts and functional noncoding RNAs, such as microRNAs and long noncoding RNAs. In this Review, we discuss the significance of these emerging mechanisms, how they mediate the actions of growth factors to augment the expression of extracellular matrix and inflammatory genes associated with DN and their potential usefulness as diagnostic biomarkers or novel therapeutic targets for DN.

Anti-miRNA-221 sensitizes human colorectal carcinoma cells to radiation by upregulating PTEN

AIM: To investigate the regulative effect of miRNA (miR)-221 on colorectal carcinoma (CRC) cell radiosensitivity and the underlying mechanisms.

METHODS: A human CRC-derived cell line was cultured conventionally and exposed to different doses of X-rays (0, 2, 4, 6 and 8 Gy). The total RNA and protein of the cells were extracted 24 h after irradiation, and the alteration of miR-221 and phosphatase and tensin homolog deleted on chromosome 10 (PTEN) gene mRNA expression was detected by real-time reverse transcriptase polymerase chain reaction (PCR). The protein alteration of PTEN in the cells was detected by Western blotting. Caco2 cells were pretreated with or without anti-PTEN-siRNA prior to the addition of pre-miR-221 or anti-miR-221 using Lipofectamine 2000. Colony formation assay and flow cytometry analysis were used to measure the surviving cell fraction and the sensitizing enhancement ratio after irradiation. Additionally, PTEN 3′-untranslated region fragment was PCR amplified and inserted into a luciferase reporter plasmid. The luciferase reporter plasmid construct was then transfected into CRC cells together with pre-miR-221 or anti-miR-221, and the luciferase activity in the transfected cells was detected.

RESULTS: The X-ray radiation dose had a significant effect on the expression of miR-221 and PTEN protein in human Caco2 cells in a dose-dependent manner. The miR-221 expression level improved gradually with the increase in irradiation dose, while the PTEN protein expression level reduced gradually. miR-221 expression was significantly reduced in the anti-miR-221 group compared with the pre-miR-221 and negative control groups (P < 0.01). Anti-miR-221 upregulated expression of PTEN protein and enhanced the radiosensitivity of Caco2 cells (P < 0.01). Moreover, the inhibitory effect was dramatically abolished by pretreatment with anti-PTEN-siRNA, suggesting that the enhancement of radiosensitivity was indeed mediated by PTEN. A significant increase of luciferase activity was detected in CRC cells that were cotransfected with the luciferase reporter plasmid construct and anti-miR-221 (P < 0.01).

CONCLUSION: Anti-miR-221 can enhance the radiosensitivity of CRC cells by upregulating PTEN.

MicroRNA-338-3p inhibits colorectal carcinoma cell invasion and migration by targeting smoothened

OBJECTIVE

To investigate the regulative effect of microRNA-338-3p on colorectal carcinoma cell invasion and migration.

METHODS

The microRNA-338-3p expression pattern of colorectal carcinoma tissues and cell lines was detected by real-time reverse transcriptase polymerase chain reaction. The protein level of smoothened was detected by western blot analysis. Furthermore, colorectal carcinoma cells were pretreated with or without anti-smoothened-small interfering ribonucleic acid prior to the addition of pre-microRNA-338-3p or anti-microRNA-338-3p. The status of colorectal carcinoma cell invasion and that of migration were detected by transwell assay and wound healing assay, respectively.

RESULTS

The expression of microRNA-338-3p was significantly down-regulated in colorectal carcinoma tissues in comparison with those in the adjacent non-tumorous tissues, and the value was negatively related to advanced tumor, node, metastasis stage and local invasion. The expression of microRNA-338-3p in colorectal carcinoma cells transfected with pre-microRNA-338-3p p was significantly increased. Furthermore, over-expression of microRNA-338-3p inhibited the expression of smoothened protein in colorectal carcinoma cells, which showed obviously suppressed invasion and migration ability. The expression of microRNA-338-3p in colorectal carcinoma cells transfected with anti-microRNA-338-3p was significantly decreased. Moreover, the down-regulated expression of microRNA-338-3p caused the up-regulated expression of smoothened protein in colorectal carcinoma cells, which showed significantly enhanced invasion and migration ability. However, anti-smoothened-small interfering ribonucleic acid largely, but not completely, reversed the effects induced by blockage of microRNA-338-3p, suggesting that the regulative effect of microRNA-338-3p on colorectal carcinoma cell invasion and migration was indeed mediated by smoothened. Additionally, smoothened was identified as a direct target of microRNA-338-3p by luciferase assay.

CONCLUSIONS

MicroRNA-338-3p could inhibit colorectal carcinoma cell invasion and migration by inhibiting smoothened expression.

MicroRNAs: potential mediators and biomarkers of diabetic complications

The incidence of diabetes is escalating worldwide and, consequently, this has become a major health care problem. Moreover, both type 1 and type 2 diabetes are associated with significantly accelerated rates of microvascular complications, including retinopathy, nephropathy, and neuropathy, as well as macrovascular complications such as atherosclerotic cardiovascular and hypertensive diseases. Key factors have been implicated in leading to these complications, including hyperglycemia, insulin resistance, dyslipidemia, advanced glycation end products, growth factors, inflammatory cytokines/chemokines, and related increases in cellular oxidant stress (including mitochondrial) and endoplasmic reticulum stress. However, the molecular mechanisms underlying the high incidence of diabetic complications, which often progress despite glycemic control, are still not fully understood. MicroRNAs (miRNAs) are short noncoding RNAs that have elicited immense interest in recent years. They repress target gene expression via posttranscriptional mechanisms and have diverse cellular and biological functions. Herein, we discuss the role of miRNAs in the pathobiology of various diabetic complications, their involvement in oxidant stress, and also the potential use of differentially expressed miRNAs as novel diagnostic biomarkers and therapeutic targets.

miRNAs and long noncoding RNAs as biomarkers in human diseases

Noncoding RNAs (ncRNAs) are transcripts that have no apparent protein-coding capacity; however, many ncRNAs have been found to play a major biological role in human physiology. Their deregulation is implicated in many human diseases, but their exact roles are only beginning to be elucidated. Nevertheless, ncRNAs are extensively studied as a novel source of biomarkers, and the fact that they can be detected in body fluids makes them extremely suitable for this purpose. The authors mainly focus on ncRNAs as biomarkers in cancer, but also touch on other human diseases such as cardiovascular diseases, autoimmune diseases, neurological disorders and infectious diseases. The authors discuss the established methods and provide a selection of emerging new techniques that can be used to detect and quantify ncRNAs. Finally, the authors discuss ncRNAs as a new strategy for therapeutic interventions.

MicroRNA-106b regulates the tumor suppressor RUNX3 in laryngeal carcinoma cells

Our study focuses on a set of laryngeal tumors that show reduced RUNX3 expression in the absence of transcriptional silencing of tumor suppressor gene RUNX3 by aberrant methylation of CpG islands. We report that the loss of expression of RUNX3 correlates with up-regulation of miR-106b in human laryngeal carcinoma tissue. The downregulation of RUNX3 is mediated by miR-106b through binding of its 3'UTR. Moreover, miR-106b can promote the proliferation and invasion of laryngeal carcinoma cells by directly targeting RUNX3, and RUXN3 knockdown can abolish this phenotype. These results shed a new insight into the mechanism of miRNA regulation in laryngeal carcinoma.