Circulating microRNAs as biomarkers for early detection of diffuse-type gastric cancer using a mouse model

Circulating miRNA as a Biomarker in Oral Cancer Liquid Biopsy

Oral cancer is currently challenging the healthcare system, with a high incidence among the population and a poor survival rate. One of the main focuses related to this malignancy is the urge to implement a viable approach for improving its early diagnosis. By introducing the use of liquid biopsy and the identification of potential biomarkers, aiming for a noninvasive approach, new advancements offer promising perspectives in the diagnosis of oral cancer. The present review discusses the potential of circulating miRNAs as oral cancer biomarkers identified in body fluids such as serum, plasma, and saliva samples of oral cancer patients. Existing results reveal an important implication of different miRNA expressions involved in the initiation, development, progression, and metastasis rate of oral malignancy. Liquid biomarkers can play a crucial role in the development of the concept of personalized medicine, providing a wide range of clinical applications and future targeted therapies.

Association between the Expression Levels of MicroRNA-101, -103, and -29a with Autotaxin and Lysophosphatidic Acid Receptor 2 Expression in Gastric Cancer Patients

Background

Gastric cancer (GC) is regarded as the most prevalent malignancy with the high mortality rate, worldwide. However, gastroscopy, a biopsy of suspected sample, and detecting CEA, CA19-9, and CA72-4 are presently used, but these diagnostic approaches have several limitations. Recently, microRNAs as the most important member of noncoding RNAs (ncRNAs) have received attention; recent evidence demonstrates that they can be used as the promising candidate biomarkers for GC diagnosis. We aimed to investigate the association between the microRNA-29a, -101, and -103 expression and autotaxin (ATX) and lysophosphatidic acid receptor 2 (LPA2) expression in GC patients. Material and Methods. The present study was conducted on 40 paired samples of primary GC tissue and adjacent noncancerous tissue. The gene expression levels of miR-101, -103, -29, ATX, and LPA2 were analyzed by quantitative reverse-transcription PCR (qRT-PCR). Besides, the protein levels of ATX and LPA2 were evaluated using western blot.

Results

The expression levels of miR-29 and miR-101 were significantly lower (p value < 0.0001), but the miR-103 and LPA2 were significantly higher in gastric tumor samples compared to the corresponding nontumor tissues (p value < 0.0001). Moreover, the diagnostic accuracy of miRs to discrimine the GC patients from noncancerous controls was reliable (miR-101, sensitivity: 82.5% and specificity: 85%; miR-103, sensitivity: 72.5% and specificity: 90%; miR-29, sensitivity: 77.5% and specificity: 70%).

Conclusion

It seems that determining the expression level of miR-101, -103, and -29, as the novel diagnostic biomarkers, has diagnostic value to distinguish GC patients from healthy individuals.

Novel biomarkers of microRNAs in gastric cancer; an overview from diagnosis to treatment

The fourth frequent disease in the world and the second cause of cancer-related death is gastric cancer (GC). In this way, over 80% of diagnoses are made in the middle to advanced degrees of the disease, underscoring the requirement for innovative biomarkers that can be identified quickly. Meaningly, biomarkers that can complement endoscopic diagnosis and be used to detect patients with a high risk of GC are desperately needed. These biomarkers will allow for the accurate prediction of therapy response and prognosis in GC patients, as well as the development of an optimal treatment strategy for each individual. Conspicoiusly, microRNAs (miRNAs) and small noncoding RNA regulates the expression of target mRNA and thereby modifies critical biological mechanisms. According to the data, abnormally miRNAs expression in GC is linked to tumor growth, carcinogenesis, aggression and distant metastasis. Importantly, miRNA expression patterns and next-generation sequencing (NGS) can also be applied to analyze kinds of tissues and cancers. Given the high death rates and poor prognosis of GC, and the absence of a clinical diagnostic factor that is adequately sensitive to GC, research into novel sensitive and specific markers for GC diagnosis is critical. In this review,we evaluate the latest research findings that suggest the feasibility and clinical utility of miRNAs in GC.

Long noncoding RNA CYTOR triggers gastric cancer progression by targeting miR-103/RAB10

Growing evidence has indicated that the long noncoding RNA (lncRNA) CYTOR is involved in the initiation and progression of malignancies, including gastric cancer. Nevertheless, the mechanisms of CYTOR in gastric cancer development are not fully understood. In the present study, we aimed to clarify the association of CYTOR, miR-103, and RAB10 in gastric cancer progression. We found that CYTOR expression was increased in metastatic gastric cancer biopsies compared with that in primary samples. CYTOR expression was significantly positively correlated with the invasiveness, lymph node metastasis, and advanced stages of gastric cancer. In addition, downregulation of CYTOR expression hampered cell proliferation and migration but induced cell apoptosis. Furthermore, CYTOR sponged miR-103 and diminished miR-103 expression, thus rescuing oncogene RAB10 expression. Knockdown of CYTOR suppressed tumor growth in human BGC823 mouse models. These findings suggest that the CYTOR/miR-103/RAB10 axis is a novel signaling pathway that facilitates gastric cancer progression. CYTOR-targeted interventions provide a rationale to improve therapies targeting gastric cancer progression.

MicroRNAs: potential biomarkers for diagnosis and prognosis of different cancers

A thorough understanding of the tumor environment and underlying genetic factors helps in the better formulation of cancer management strategies. Availability of efficient diagnostic and prognostic biomarkers facilitates early detection and progression of the disease. MicroRNAs affect different biological processes participating in tumorigenesis through regulation of their target genes. An expanding list of unique RNAs and understanding of their regulatory role has opened up a new field in cancer research. Based on a comprehensive literature search, we identified 728 miRNAs dysregulated in sixteen cancer types namely bladder cancer (BC), breast cancer (BrC), cervical cancer (CC), colorectal cancer (CRC), esophageal cancer (EC), endometrial cancer (EnC), gastric cancer (GC), hepatocellular cancer (HCC), head and neck squamous cell cancer (HNSCC), lung cancer (LC), ovarian cancer (OC), pancreatic cancer (PC), prostate cancer (PrC), renal cell cancer (RCC), skin cancer (SC), and thyroid cancer (TC). Expression of 43 miRNAs was either upregulated or downregulated in six or more of these cancers. Finally, seven miRNAs namely mir-18a, mir-21, mir-143/145, mir-210, mir-218, mir-221, showing maximum dysregulation, either up- or down-regulation in the majority of cancers, were selected for a detailed presentation of their expression and evaluation of their potential as biomarkers in the diagnosis and prognosis of different cancers.

Non-coding RNAs in gastric cancer

Non-coding RNAs (ncRNAs) are functional RNA molecules that play crucial regulatory roles in many fundamental biological processes. The dysregulation of ncRNAs is significantly associated with the progression of human cancers, including gastric cancer. In this review, we have summarized the oncogenic or tumor-suppressive roles and the regulatory mechanisms of lncRNAs, miRNAs, circRNAs and piRNAs, and have discussed their potential as biomarkers or therapeutic targets in gastric cancer.

MiR-17-5p promotes cellular proliferation and invasiveness by targeting RUNX3 in gastric cancer

BACKGROUND

Dysregulated microRNAs (miRNAs/miRs) directly modulate the biological functions of gastric cancer (GC) cells and contribute to the initiation and progression of GC. MiR-17-5p and runt-related transcription factor 3 (RUNX3) have been reported to be related to GC progression; however, the specific interaction between miR-17-5p and RUNX3 in GC require further investigation.

METHODS

Western blotting, real-time PCR and immunohistochemistry were used to study the expression level of miR-17-5p and RUNX3 in gastric cancer tissues and plasma. The biological function of miR-17-5p was examined by measuring cell proliferation, apoptosis and cell invasion in vitro; the target gene of miR17-5p was identified by luciferase reporter assays, RNA Binding protein immunoprecipitation (RIP) and western blotting. In vivo animal study was conducted to confirm the role of miR-17-5p during tumorigensis of gastric cancer.

RESULTS

This study showed that miR17-5p was upregulated in the plasma and tissues of patients with GC, while RUNX3 was downregulated in GC tissues. Functional experiments indicated that miR-17-5p mimics promoted the proliferation and invasion of GC via suppressing apoptosis in vitro. Furthermore, bioinformatics prediction, luciferase reporter assays, reverse transcription quantitative polymerase chain reaction assays, RIP and western blotting analysis demonstrated that RUNX3 was a direct target gene of miR-17-5p in GC. In addition, overexpression of RUNX3 suppressed the proliferation and invasiveness of GC cells. In vivo data indicated miR-17-5p agomir significantly promoted tumor growth. In contrast, miR-17-5p antagomir notably decreased tumor volume compared with control group.

CONCLUSIONS

MiR-17-5p promoted the progression of GC via directly targeting RUNX3, suggesting that miR-17-5p and RUNX3 could be considered as diagnostic and therapeutic targets for patients with GC.

Downregulation of serum miR-194 predicts poor prognosis in osteosarcoma patients

BACKGROUND

Circulating microRNAs (miRNAs) have promising potential as diagnostic and prognostic biomarkers for osteosarcoma. This study aimed to explore the expression pattern of serum miR-194 and its potential clinical value in patients with osteosarcoma.

METHODS

Messenger RNA was isolated from serum sample from 124 osteosarcoma patients, 60 periostitis patients and 60 healthy volunteers. The serum miR-194 level was then examined by quantitative real-time polymerase chain reaction (qRT-PCR). The bioinformatic analysis of the downstream targets of miR-194 was also performed.

RESULTS

The results showed serum miR-194 levels were significantly decreased in osteosarcoma patients compared to those in periostitis patients or healthy controls. Receiver-operating characteristic (ROC) analysis demonstrated that serum miR-194 had a good diagnostic value for identifying osteosarcoma subjects from periostitis patients and normal controls. In addition, serum miR-194 levels were dramatically increased following surgery in osteosarcoma cases. Moreover, low serum miR-194 expression was strongly correlated with positive metastasis and advanced clinical stage, as well as worse survival. Furthermore, serum miR-194 was confirmed to be an independent prognostic biomarker for osteosarcoma. Bioinformatic analysis showed that the downstream targeted genes of miR-194 were closely associated with cancer initiation and development.

CONCLUSION

In conclusion, our results have demonstrated that serum miR-194 might serve as a novel and promising biomarker for the detection and prognosis of osteosarcoma.

Alteration in Expression of miR-32 and FBXW7 Tumor Suppressor in Plasma Samples of Patients with T-cell Acute Lymphoblastic Leukemia

Background

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive and malignant neoplasm that arises from the hematopoietic T-cell precursors. Inactivation of FBXW7 gene is frequently observed in T-cell acute lymphoblastic leukemia, suggesting a significant tumor-suppressive role for FBXW7 in the pathobiology of this leukemia. Considering the role of microRNAs in cell proliferation and regulation of apoptosis, the aim of this study was to identify novel oncogenic microRNAs that suppress FBXW7 in patients with T-ALL.

Patients and Methods

The expression levels of two bioinformatically predicted microRNAs – miR-32 and miR-107 were compared in patients with T-ALL and a control group. A total of 80 plasma samples were subjected to RNA extraction, and the microRNA expression profiles were assessed by the RT-qPCR. The expression level of miR-103 was used as the endogenous reference for normalization of quantitative data.

Results

The plasma levels of miR-32 and miR-107 in patients with T-ALL were significantly higher (5.65, P < 0.001) and lower (0.432, P = 0.002), respectively. On the other hand, the expression levels of FBXW7 gene were significantly downregulated by –76.9 fold in T-ALL patients (P < 0.001). The results of the ROC curve analysis indicated that overexpression of miR-32 might be used to distinguish T-ALL patients with reasonable sensitivity and specificity.

Conclusion

miR-32 is considered as a novel oncomir that targets FBXW7 and might have a role in the etiology or progression of T-ALL. Furthermore, miR-32 can potentially serve as a non-invasive biomarker for detection of T-ALL.

Clinical significance and prognostic role of hypoxia-induced microRNA 382 in gastric adenocarcinoma

Hypoxia and angiogenesis are critical components in the progression of solid cancer, including gastric cancers (GCs). miR-382 has been identified as a hypoxia-induced miR (hypoxamiR), but the clinical significance in GCs has not been identified yet. To explore the clinical and prognostic importance of miR-382 in GCs, the surgical specimens of 398 patients with GCs in KNU hospital in Korea, the total of 183 patients was randomly selected using simple sampling methods and big data with 446 GCs and 45 normal tissues from the data portal (https://portal.gdc.cancer.gov/) were analysed. Expression of miR-382 as well as miR-210, as a positive control hypoxamiR by qRT-PCR in histologically malignant region of GCs showed significantly positive correlation (R = 0.516, p<0.001). High miR-210 and miR-382 expression was significantly correlated with unfavorable prognosis including advanced GCs (AGC), higher T category, N category, pathologic TNM stage, lymphovascular invasion, venous invasion, and perinueral invasion, respectively (all p<0.05). In univariate analysis, high miR-210 expression was significantly associated with worse overall survival (OS) (p = 0.036) but not high miR-382. In paired 60 gastric normal and cancer tissues, miR-382 expression in cancer tissues was significantly higher than normal counterpart (p = 0.003), but not miR-210 expression. However, by increasing the patient number from the big data analysis, miR-210 as well as miR-382 expression in tumor tissues was significantly higher than the normal tissues. Our results suggest that miR-382, as novel hypoxamiR, can be a prognostic marker for advanced GCs and might be correlated with metastatic potential. miR-382 might play important roles in the aggressiveness, progression and prognosis of GCs. In addition, miR-382 give a predictive marker for progression of GCs compared to the normal or preneoplastic lesion.

Plasma Level of MicroRNAs, MiR-107, MiR-194 and MiR-210 as Potential Biomarkers for Diagnosis Intestinal-Type Gastric Cancer in Human

Background:

Timely and sensitive diagnosis of gastric cancer is crucial for efficient treatment and survival of the patients. microRNAs have been considered as diagnostic biomarkers in different type of cancers including gastric cancer. In the present study, the expression profile of four microRNAs, miR-103, miR-107, miR-194 and miR-210 were evaluated in patients with intestinal-type of gastric cancer (IGC) in order to assess their diagnosis utility as noninvasive biomarkers.

Methods:

A total number of 100 plasma samples from patients with gastric cancer and healthy controls were obtained and total RNA was extracted using a commercial monophasic solution of phenol and guanidium thiocyanate. Reverse transcription (RT) reactions were performed by specific stem-loop RT primers and M-MuLV RT-enzyme. The expression patterns of microRNAs were assessed using reverse transcription quantitative real-time PCR (RT-qPCR) method and the expression of SNORD47 RNA was used as the reference for normalization.

Results:

The results indicate that the plasma levels of miR-107, miR-194, and miR-210 were significantly lower in patients. Receiver operating characteristic (ROC) curve analysis showed that the patients could be distinguished from healthy individuals at the cutoff levels of 0.504, 0.266, and 0.394 of miR-107, miR-194, and miR-210, respectively. On the other hand, the expression levels of these miRNAs were not significantly different in different clinicopathological stages of the disease.

Conclusion:

These findings suggest that the plasma levels of miR-107, miR-194 and miR-210 were downregulated in patients with ICG and propose these molecules as potential non-invasive biomarkers for detection of IGC.

Up-regulation of tumor necrosis factor-α pathway survival genes and of the receptor TNFR2 in gastric cancer

BACKGROUND

Gastric carcinogenesis can be induced by chronic inflammation triggered by Helicobacter pylori (H. pylori) infection. Tumor necrosis factor (TNF)-α and its receptors (TNFR1 and TNFR2) regulate important cellular processes, such as apoptosis and cell survival, and the disruption of which can lead to cancer. This signaling pathway is also modulated by microRNAs (miRNAs), altering gene expression.

AIM

To evaluate the mRNA and miRNAs expression involved in the TNF-α signaling pathway in gastric cancer (GC) tissues and its relationship.

METHODS

Quantitative polymerase chain reaction (qPCR) by TaqMan^® assay was used to quantify the RNA transcript levels of TNF-α signaling pathway (TNF, TNFR1, TNFR2, TRADD, TRAF2, CFLIP, NFKB1, NFKB2, CASP8, CASP3) and miRNAs that targets genes from this pathway (miR-19a, miR-34a, miR-103a, miR-130a, miR-181c) in 30 GC fresh tissue samples. Molecular diagnosis of H. pylori was performed by nested PCR for gene HSP60. A miRNA:mRNA interaction network was construct using Cytoscape v3.1.1 from the in silico analysis performed using public databases.

RESULTS

Up-regulation of cellular survival genes as TNF, TNFR2, TRADD, TRAF2, CFLIP, and NFKB2, besides CASP8 and miR-34a was observed in GC tissues, whereas mediators of apoptosis such as TNFR1 and CASP3 were down-regulated. When the samples were stratified by histological type, the expression of miR-103a and miR-130a was significantly increased in the diffuse-type of GC compared to the intestinal-type. However, no influence of H. pylori infection was observed on the expression levels of mRNA and miRNAs analyzed. Moreover, the miRNA:mRNA interaction network showed several interrelations between the miRNAs and their target genes, highlighting miR-19a and miR-103a, which has as predicted or validated target a large number of genes in the TNF-α pathway, including TNF, TNFR1, TNFR2, CFLIP, TRADD, CASP3 and CASP8.

CONCLUSION

Our findings show that cell survival genes mediated by TNF/TNFR2 binding is up-regulated in GC favoring its pro-tumoral effect, while pro-apoptotic genes as CASP3 and TNFR1 are down-regulated, indicating disbalance between apoptosis and cell proliferation processes in this neoplasm. This process can also be influenced by an intricate regulatory network of miRNA:mRNA.

Novel miRNA PC-5P-12969 in Ischemic Stroke

Circulating microRNAs (miRNAs) have been used effectively as peripheral biomarkers and mechanistic targets for human diseases such as stroke, Alzheimer's, and cancer. The purpose of our study is to determine noninvasive, blood-based early detectable biomarkers for ischemic stroke (IS). Based on our previous global miRNA sequencing study, four miRNAs were previously unreported (novel) in IS condition. Among these, miRNA PC-5P-12969 was exclusively expressed in the IS condition; otherwise, it was not expressed in normal condition, and therefore, we focused on miRNA PC-5P-12969 for further studies. In the present study, we investigated novel miRNA PC-5P-12969 for its expression levels using quantitative real-time PCR assay (qRT-PCR) in an in vitro, oxygen, and glucose deprivation/reoxygenation (OGD/R)-treated mouse primary hippocampal neuronal cells (HT22) and in an in vivo using a photothrombotic stroke model. In an in vitro study of stroke-induced HT22 cells, we found a two fold increase of PC-5P-12969 expression levels, in agreement with our original global miRNA study. In the cerebral cortex of photothrombotic stroke mice, we found significantly upregulated levels of PC-5P-12969 in 4 hours and 1 day post-stroke relative to the control mice. However, we did not find any change in the expression of PC-5P-12969 in the cerebellum (unaffected in IS) of both stroke and control mice. Based on findings from this study, together with our earlier original global microRNA study results, we conclude that PC-5P-12969 is a potential candidate of the peripheral marker and also a drug target for IS. This is the first study validating that the miRNA PC-5P-12969, might be a potential biomarker for IS.

Upregulation of the APE1 and H2AX genes and miRNAs involved in DNA damage response and repair in gastric cancer

Gastric cancer remains one of the leading causes of cancer-related death worldwide, and most of the cases are associated with Helicobacter pylori infection. This bacterium promotes the production of reactive oxygen species (ROS), which cause DNA damage in gastric epithelial cells. In this study, we evaluated the expression of important genes involved in the recognition of DNA damage (ATM, ATR, and H2AX) and ROS-induced damage repair (APE1) and the expression of some miRNAs (miR-15a, miR-21, miR-24, miR-421 and miR-605) that target genes involved in the DNA damage response (DDR) in 31 fresh tissues of gastric cancer. Cytoscape v3.1.1 was used to construct the postulated miRNA:mRNA interaction network. Analysis performed by real-time quantitative PCR exhibited significantly increased levels of the APE1 (RQ = 2.55, p < 0.0001) and H2AX (RQ = 2.88, p = 0.0002) genes beyond the miR-421 and miR-605 in the gastric cancer samples. In addition, significantly elevated levels of miR-21, miR-24 and miR-421 were observed in diffuse-type gastric cancer. Correlation analysis reinforced some of the gene:gene (ATM/ATR/H2AX) and miRNA:mRNA relationships obtained also with the interaction network. Thus, our findings show that tumor cells from gastric cancer presents deregulation of genes and miRNAs that participate in the recognition and repair of DNA damage, which could confer an advantage to cell survival and proliferation in the tumor microenvironment.

Pleiotropic functions of miR107 in cancer networks

MicroRNAs are short regulatory RNAs that posttranscriptionally modulate gene expression and thus play crucial roles in controlling cancer-onset, growth, and progression processes. miR107, a highly conserved microRNA that maps to intron 5 of the PANK1 gene, contributes to the regulation of normal and tumor biological processes. Studies have reported that miR107 has oncogenic or tumor-suppressor functions in different human tumors. The pleiotropic functions of miR107 in various cancers are achieved via its targeting different genes that are involved in tumor proliferation, invasiveness, metastasis, angiogenesis, and chemotherapy-response pathways. The carcinogenicity or cancer-suppressor effects of miR107 occur in a tissue- and cell-specific manner, and the expression level of miR107 can be affected by various factors, including epigenetic and genetic factors, treatment exposure, and daily diet. A comprehensive analysis of the current literature suggests that miR107 functions as a central element in the regulation of cancer networks and can be used as a potential diagnostic and prognostic biomarker and drug target for therapeutic intervention.

MicroRNAs as potential biomarkers for diagnosis, therapy and prognosis of gastric cancer

Despite the widespread use of endoscopy and conventional tumor biomarkers, gastric cancer (GC) remains one of the most frequent causes of cancer-related deaths worldwide due to its late diagnosis and poor response to treatment. Valuable and practical biomarkers are urgently needed to screen patients with a high risk of GC that can complement endoscopic diagnosis. Such biomarkers will enable the efficient prediction of therapeutic response and prognosis of GC patients and favor the establishment of an effective treatment strategy for each and every patient. MicroRNAs (miRNAs) are a class of small non-coding RNA sequences that play important roles in modulating key biological processes by regulating the expression of target genes. Expectedly, miRNAs are abnormally expressed within the tumor tissue and in associated biological fluids of GC patients including their blood, gastric juice, and urine. Accumulating evidence indicates that miRNAs are potential biomarkers with multiple diagnostic functions for GC. Here, we review recent advances and challenges in using miRNAs, particularly biofluid miRNAs, as GC biomarkers with potential clinical applications including diagnosing, clinically staging, and predicting malignant behaviors, therapy response, recurrence after surgery and survival time.

miRNA-103a-3p Promotes Human Gastric Cancer Cell Proliferation by Targeting and Suppressing ATF7 in vitro

Studies have revealed that miR-103a-3p contributes to tumor growth in several human cancers, and high miR-103a-3p expression is associated with poor prognosis in advanced gastric cancer (GC) patients. Moreover, bioinformatics analysis has shown that miR-103a-3p is upregulated in The Cancer Genome Atlas (TCGA) stomach cancer cohort. These results suggest that miR-103a-3p may function as an oncogene in GC. The present study aimed to investigate the role of miR-103a-3p in human GC. miR-103a-3p expression levels were increased in 33 clinical GC specimens compared with adjacent nontumor stomach tissues. Gain- and loss-of-function studies were performed to identify the correlation between miR-103a-3p and tumorigenesis in human GC. Inhibiting miR-103a-3p suppressed GC cell proliferation and blocked the S-G2/M transition in MKN-45/SGC-7901 cells, whereas miR-103a-3p overexpression improved GC cell proliferation and promoted the S-G2/M transition in vitro. Bioinformatics and dual-luciferase reporter assays confirmed that ATF7 is a direct target of miR-103a-3p. Analysis of the TCGA stomach cancer cohort further revealed that miR-103a-3p expression was inversely correlated with ATF7 expression. Notably, silencing ATF7 showed similar cellular and molecular effects as miR-103a-3p overexpression, namely, increased GC cell proliferation, improved CDK2 expression and decreased P27 expression. ATF7 overexpression eliminated the effects of miR-103a-3p expression. These findings indicate that miR-103a-3p promotes the proliferation of GC cell by targeting and suppressing ATF7 in vitro.

Evaluation of serum microRNA biomarkers for gastric cancer based on blood and tissue pools profiling: the importance of miR-21 and miR-331

BACKGROUND

High stability and disease-specific disarrangements suggest that microRNA molecules (miRNAs) present in body fluids are ideally suited for diagnostic applications, including gastric cancer (GC). However, the actual source of circulating miRNA biomarkers in GC has not been adequately evaluated, particularly in the Western populations that have some distinct characteristics compared with Asian patients.

METHODS

Twenty treatment-naive patients with GC along with 20 cancer-free controls were recruited. miRCURY LNA miRNA microarrays were used for miRNA expression profiling in primary tumours and adjacent healthy mucosa. Differentially expressed serum miRNAs were identified with a high throughput TaqMan OpenArray technology in tumour-draining veins of the portal system, as well as peripheral blood of the patients and controls.

RESULTS

Tissue profiling identified 108 sequences differentially expressed between primary tumours and adjacent mucosa (87 upregulated and 21 downregulated). Twenty miRNAs found in serum of GC patients showed expression levels higher than in controls. However, only seven of these molecules were overexpressed in primary tumours (miR-130a, miR-331, miR-19a, miR-223, miR-106a, miR-21, and miR-374). Moreover, expression of miR-331 and miR-21 was significantly higher in the peripheral circulation compared to tumour-draining veins of the portal system.

CONCLUSIONS

The results indicate that the majority of potential serum miRNA biomarkers may originate from tissues other than the primary tumour.

Biological implications and clinical value of mir-210 in gastrointestinal cancer

Hypoxia, a common feature of tumor microenvironment, is known to accelerate tumor development and growth by promoting the formation of a neoplastic environment. Recent studies have provided a wealth of evidence that miRNAs are significant members of the adaptive response to low oxygen in tumors. miR-210 is one of the hypoxia-induced miRNAs, which has been reported extensively in cancer researches. However, there is no systematic discussion about the role of miR-210 in gastrointestinal cancer. We conducted a literature research in database including PubMed, Elsevier Science Direct and Medline before 16 September 2016, in order to collect articles of miR-210 in gastrointestinal cancer. Areas covered: In the present review, we mainly discuss the following aspects: hypoxia-induced dysregulation of miR-210, the expression of miR-210 and tumorigenesis, the resultant changes of miR-210 targets and its roles in different types of gastrointestinal cancer progression, the diagnostic, therapeutic and prognostic value of miR-210 in gastrointestinal cancer. Expert commentary: Numerous researches have demonstrated the values of miR-210 in cancer diagnosis, prognosis and targeted therapies, especially in gastrointestinal cancers. However, there are also some existing problems and challenges in translating the new research findings into clinical utility. Further investigations and studies are still urgently required.

miR-103 Promotes Proliferation and Metastasis by Targeting KLF4 in Gastric Cancer

MicroRNAs (miRNAs) play important roles in the cancer development and progression; overexpression of miR-103 has been identified in various tumors. However, its biological function and regulatory mechanism involved in modulation of human gastric cancer (GC) remain largely unknown. This study aimed to confirm clinical significance of miR-103 and investigate its biological role and underlying mechanism in GC. Real-time quantitative PCR (qRT-PCR) revealed miR-103 was highly expressed in GC tissues and cell lines. miR-103 expression was correlated closely with tumor size, Lauren’s classification, and lymph node metastasis. Importantly, Kaplan-Meier analysis revealed that high expression of miR-103 was significantly associated with poor overall survival and disease-free survival of GC patients. Downregulation of miR-103 by transfecting with miR-103 inhibitor significantly suppressed cell proliferation, induced apoptosis, inhibited migration and invasion in vitro and in vivo. Furthermore, miRNA target databases and luciferase reporter assay confirmed that Krüppel-like Factor-4 (KLF4) was a direct target of miR-103 in GC, and there was a significant inverse correlation between miR-103 and KLF4 expression in GC tissues. Moreover, KLF4 downregulation could rescue miR-103’s oncogenic effect on GC cell proliferation, apoptosis, migration, and invasion. Therefore, these results suggested that miR-103 overexpression could contribute to tumor progression by suppressing KLF4, and it might serve as a promising candidate for the prognosis of GC patients.

MicroRNA-146a affects the chemotherapeutic sensitivity and prognosis of advanced gastric cancer through the regulation of LIN52

The present study aimed to evaluate the correlation between the expression of microRNA-146a (miR-146a) and its target gene, LIN52, in advanced gastric cancer, and determine their potential effects on chemotherapeutic sensitivity and prognosis. Total RNA was extracted from 93 tissue samples of advanced gastric cancer and corresponding adjacent non-tumor tissues to quantify the relative expression levels of miR-146a using reverse transcription-quantitative polymerase chain reaction analysis. The expression of LIN52 was detected in tumors and normal tissues using immunohistochemical analysis. Correlation analysis was performed to assess the correlation between the expression of miR-146a and LIN52 and clinicopathological parameters of gastric cancer, including clinical diagnostic specificity, clinical tumor-necrosis-metastasis staging, lymph node metastasis, differentiation grade, chemotherapeutic sensitivity and prognosis. The expression of miR-146a in advanced gastric cancer tissues was lower, compared with that in the adjacent non-tumor tissues, and was negatively correlated with lymph node metastasis (P<0.05). Gastric cancer tissues with a low expression level of miR146a exhibited an increased expression level of LIN52 (P<0.05). Receiver operating characteristic curve regression analysis showed that miR-146a had 98% sensitivity in distinguishing gastric cancer tissues and adjacent non-tumor tissues. A high expression of miR-146a in gastric cancer was associated with improved treatment efficacy in patients. The chemotherapeutic sensitivity of patients with tumors expressing high levels of miR-146a was significantly higher, compared with that of patients with tumors expressing low levels of miR-146a (P<0.05). The expression of miR-146a was low in advanced gastric cancer tissues. As a tumor suppressor gene in advanced gastric cancer, miR-146a had a significant negative correlation with LIN52. High expression levels of miR-146a in advanced gastric cancer tissue may be associated with improved treatment efficacy of chemotherapy, suggesting that miR-146a may be a molecular marker for the diagnosis, prediction of treatment efficacy and prognosis of advanced gastric cancer.

Plasma microRNA-103, microRNA-107, and microRNA-194 levels are not biomarkers for human diffuse gastric cancer

PURPOSE

Diffuse-type gastric cancer (DGC) carries a poor prognosis. Effective screening is one measure that might improve the prognosis of this disease. An E-cadherin/p53 double-conditional knockout (DCKO) mouse line recapitulates human DGC morphologically and molecularly. Three circulating microRNAs (miRNA) (miR-103, miR-107, miR-194) in DCKO mice have been identified as biomarkers for DGC. We sought to evaluate whether these circulating miRNAs could be used for the detection of human DGC.

METHODS

Subjects were 50 patients with DGC. Controls were first-time outpatients at Aichi Cancer Center Hospital, age- and sex-matched, without a cancer diagnosis. Total RNA containing miRNA was extracted from the plasma samples and then reverse-transcribed. The levels of miRNAs in plasma samples were quantitatively determined by real-time RT-PCR. Spiked-in cel-miR-39 was analyzed as a normalization control.

RESULTS

Levels of the three plasma microRNA levels in DGC cases with or without an intestinal component were not significantly different from those in control subjects. The areas under the receiver operating characteristic curve of miR-103, miR-107, and miR-194 were 0.548, 0.563, and 0.512, respectively.

CONCLUSIONS

In contrast to the DCKO mouse model, plasma miR-103, miR-107, and miR-194 levels are not altered in DGC and are not suitable for human DGC screening.

High expression of miR-16 and miR-451 predicating better prognosis in patients with gastric cancer

PURPOSE

To investigate the expression pattern of miR-16 and miR-451 and evaluate their prognostic value in 180 GC patients undergoing surgery.

METHODS

In our previous study, a panel of five circulating miRNAs (miR-16, miR-25, miR-92a, miR-451 and miR-486-5p) can be used as a potential biomarker for detecting of early-stage gastric carcinoma (GC). Tissue microarrays were constructed from 180 patients with GC after surgery. MiR-16 and miR-451 expression was detected by miRNA-locked nucleic acid in situ hybridization, and their relationship with clinicopathological parameters and overall survival was analyzed.

RESULTS

MiR-16 expression was decreased in 30.6 % (55/180) of GC, increased in 54.4 % (98/180) and unchanged in 15.0 % (27/180), compared with paracancerous normal tissue (P < 0.001). MiR-451 expression was decreased in 17.8 % (32/180), increased in 62.8 % (113/180) and unchanged in 19.4 % (35/180) of GC, compared with paracancerous normal tissue (P < 0.001).Univariate analysis indicated that low miR-16 and miR-451 expression, tumor stage, tumor status, node status and tumor size were significant negative prognostic predictors for overall survival in patients with GC (P < 0.001, P < 0.001, P = 0.002, P < 0.001 and P = 0.001, respectively). Multivariate regression analysis demonstrated that stage [hazard ratio (HR) 1.80; 95 % confidence interval (CI) 1.0-3.26; P = 0.05], low expression of miR-16 (HR 2.26; 95 % CI 1.51-3.40; P < 0.001) and miR-451 (HR 2.01; 95 % CI 1.36-2.96; P < 0.001) predicted shorter OS, while tumor status (HR 1.59; 95 % CI 0.73-3.48 P = 0.242), lymph node metastasis (HR 1.41; 95 % CI 0.71-2.82; P = 0.326) and tumor size (HR 1.53; 95 % CI 0.92-2.55; P = 0.099) were not. Moreover, patients with both miR-16 and miR-451 high expression have better OS than those with two miRNAs unchanged or low expression in GC tissues. Patients with both miR-16 and miR-451 high have better OS than patients with single miR-451 high expression.

CONCLUSIONS

High expression of miR-16 and miR-451 was associated with longer OS in GC patients. Especially patients with miR-16 and miR-451 double high expression will predict better OS. MiR-16 and miR-451 may be used as novel makers to evaluate prognosis and provide a new treatment target in GC.

MicroRNA-210 and its theranostic potential

INTRODUCTION

MicroRNAs (miRNAs) are a set of small single-stranded noncoding RNAs with diverse biological functions. As a prototypical hypoxamir, human microRNA-210 (hsa-miR-210) is one of the most widely studied miRNAs thus far. In addition to its involvement in sophisticated regulation of numerous biological processes, miR-210 has also been shown to be associated with the development of different human diseases including various types of cancers, cardiovascular and cerebrovascular diseases, and immunological diseases. Given its multi-faceted functions, miR-210 may serve as a novel and promising theranostic target for prevention and treatment of diseases. Areas covered: This review aims to provide a comprehensive overview of miR-210, the regulation of its expression, biological functions and molecular mechanisms, with particular emphasis on its diagnostic and therapeutic potential. Expert opinion: Although the exact roles of miR-210 in various diseases have not been fully clarified, targeting miR-210 may be a promising therapeutic strategy. Further investigations are also needed to facilitate therapeutic-clinical applications of miR-210 in human diseases.

Expression and prognostic value of miR-92a in patients with gastric cancer

MicroRNA (miR)-92 expression is often aberrant in human cancers. However, its expression in gastric carcinoma and its relation to clinicopathological features and prognosis are unclear.Tissue microarrays were constructed from 180 patients with gastric cancer (GC), who were undergoing radical resection. MiR-92a expression was detected using miRNA-locked nucleic acid in situ hybridization, and its correlation with clinicopathological features and overall survival was analyzed. MiR-92a expression was decreased in 13.9 % (25/180) of GC, increased in 81.1 % (146/180), and unchanged in 5.0 % (9/180), compared with paracancerous normal tissue (P < 0.001). Univariate analysis showed that high miR-92a expression, tumor stage, tumor status, node status, and tumor size were significant negative prognostic predictors for overall survival in patients with GC (P < 0.001, P < 0.001, P = 0.008, P < 0.001, and P = 0.001, respectively). High miR-92a expression still remained a significant predictor of shorter survival in stage II (n = 56, P = 0.001) and stage III (n = 92, P = 0.009) GC. Multivariate regression analysis demonstrated that tumor status (hazard ratio [HR], 3.10; 95 % confidence interval [CI], 1.51-6.37; P = 0.002), stage (HR, 3.54; 95 % CI, 1.65-7.63; P = 0.000), lymph node metastasis (HR, 2.83; 95 % CI, 1.88-4.28; P = 0.000), high expression of miR-92a (HR, 2.94; 95 % CI, 2.01-4.31; P = 0.000), and tumor size (HR, 2.34; 95 % CI, 1.45-3.79; P = 0.002) predicted shorter OS.High expression of miR-92a compared with adjacent normal tissues was associated with shorter OS. MiR-92a may thus be useful for evaluating prognosis and may provide a novel treatment target in patients with GC.

Subclinical Detection of Diabetic Cardiomyopathy with MicroRNAs: Challenges and Perspectives

The prevalence of cardiac diabetic diseases has been increased around the world, being the most common cause of death and disability among diabetic patients. In particular, diabetic cardiomyopathy is characterized with a diastolic dysfunction and cardiac remodelling without signs of hypertension and coronary artery diseases. In an early stage, it is an asymptomatic disease; however, clinical studies demonstrate that diabetic myocardia are more vulnerable to injury derived by acute myocardial infarct and are the worst prognosis for rehabilitation. Currently, biochemical and imaging diagnostic methods are unable to detect subclinical manifestation of the disease (prior to diastolic dysfunction). In this review, we elaborately discuss the current scientific evidences to propose circulating microRNAs as promising biomarkers for early detection of diabetic cardiomyopathy and, then, to identify patients at high risk of diabetic cardiomyopathy development. Moreover, here we summarise the research strategies to identify miRNAs as potential biomarkers, present limitations, challenges, and future perspectives.

Serum microRNAs as potential noninvasive biomarkers for glioma

Gliomas are derived from astroglial precursors or astrocytes, accounting for 40 % central nervous system tumors. MicroRNAs (miRNAs) are a class of endogenous, small (19- to 23-nucleotides) non-coding RNAs involved in cancer progression. Recent studies show that circulating miRNAs are associated with the clinicopathological features and prognosis of gliomas. Serum miRNAs may serve as novel biomarkers for gliomas diagnosis. This review explores the possibilities of using serum miRNAs as prognostic, diagnostic markers, and therapeutic targets in gliomas.

Influence of statins on distinct circulating microRNAs during prolonged aerobic exercise

Statins exacerbate exercise-induced skeletal muscle injury. Muscle-specific microRNAs (myomiRs) increase in plasma after prolonged exercise, but the patterns of myomiRs release after statin-associated muscle injury have not been examined. We examined the relationships between statin exposure, in vitro and in vivo muscle contraction, and expression of candidate circulating myomiRs. We measured plasma levels of myomiRs, circulating microRNA-1 (c-miR-1), c-miR-133a, c-miR-206, and c-miR-499-5p from 28 statin-using and 28 nonstatin-using runners before (PRE), immediately after (FINISH), and 24 h after they ran a 42-km footrace (the 2011 Boston marathon) (POST-24). To examine these cellular-regulation myomiRs, we used contracting mouse C2C12 myotubes in culture with and without statin exposure to compare intracellular and extracellular expression of these molecules. In marathoners, c-miR-1, c-miR-133a, and c-miR-206 increased at FINISH, returned to baseline at POST-24, and were unaffected by statin use. In contrast, c-miR-499-5p was unchanged at FINISH but increased at POST-24 among statin users compared with PRE and runners who did not take statins. In cultured C2C12 myotubes, extracellular c-miR-1, c-miR-133a, and c-miR-206 were significantly increased by muscle contraction regardless of statin use. In contrast, extracellular miR-499-5p was unaffected by either isolated statin exposure or isolated carbachol exposure but it was increased when muscle contraction was combined with statin exposure. In summary, we found that statin-potentiated muscle injury during exercise is accompanied by augmented extracellular release of miR-499-5p. Thus c-miR-499-5p may serve as a biomarker of statin-potentiated muscle damage.

May Circulating microRNAs be Gastric Cancer Diagnostic Biomarkers?

Gastric cancer (GC) is the third leading cause of cancer-related deaths. More than 80% of the diagnosis was made at the advanced stages of the disease, highlighting the urgent demand for novel biomarkers that can be used for early detection. Recently, a number of studies suggest that circulating microRNAs (miRNAs) could be potential biomarkers for GC diagnosis. Cancer-related circulating miRNAs, as well as tissue miRNAs, provide a hopeful prospect of detecting GC at early stages, and the prospective participation of miRNAs in biomarker development will enhance the sensitivity and specificity of diagnostic tests for GC. As miRNAs in blood are stable, their potential value as diagnostic biomarkers in GC has been explored over the past few years. However, due to the inconsistent or sometimes conflicting reports, large-scale prospective studies are needed to validate their potential applicability in GC diagnosis. This review summarizes the current development about potential miRNA biomarkers for GC diagnosis and the obstacles hindering their clinical usage.

Oxidized low-density lipoprotein is a common risk factor for cardiovascular diseases and gastroenterological cancers via epigenomical regulation of microRNA-210

Hyperlipidemia, including the oxidized low-density lipoprotein (oxLDL) accumulation, is a risk and highly associated with the development of cancers and cardiovascular diseases. microRNA-210 (miR-210), a hypoxia-responsive microRNA regulated by HIF-1α, has been implicated in cancer and cardiovascular disease formation. Furthermore, Bioinformatics analysis revealed that the promoter of the miR-210 gene contains CpG-rich regions. It is unclear whether miR-210 expression could be epigenetically regulated in these disease progresses. The study aimed to explore the relationships between lipid and miR-210 in the context of cardiovascular disease and gastrointestinal cancer. We demonstrated oxLDL can decrease methylation in the miR-210 promoter to up-regulate miR-210. HIF-1α can bind to miR-210 promoter, but this HIF-1α binding site can be blocked by methylation. We showed that subjects of carotid atherosclerosis, stroke patients and cancer patients had hypomethylation in the miR-210 promoter, especially the HIF-1α binding site. Furthermore, miR-210 can directly inhibit sprouty-related EVH1 domain 2 (SPRED2) expressions, and SPRED2 reduces cell migration via ERK/c-Fos/MMPs pathways. Increased miR-210 and reduced SPRED2 levels were found in aorta of mice under high-fat diet and tumor tissues, which implied that miR-210 can be an underlying mechanism to explain oxLDL as a common risk factor for cardiovascular disease and gastrointestinal cancer.

Circulating microRNAs and long non-coding RNAs in gastric cancer diagnosis: An update and review

Gastric cancer (GC) is the fourth most common cancer and the third leading cause of cancer mortality worldwide. MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are the most popular non-coding RNAs in cancer research. To date, the roles of miRNAs and lncRNAs have been extensively studied in GC, suggesting that miRNAs and lncRNAs represent a vital component of tumor biology. Furthermore, circulating miRNAs and lncRNAs are found to be dysregulated in patients with GC compared with healthy individuals. Circulating miRNAs and lncRNAs may function as promising biomarkers to improve the early detection of GC. Multiple possibilities for miRNA secretion have been elucidated, including active secretion by microvesicles, exosomes, apoptotic bodies, high-density lipoproteins and protein complexes as well as passive leakage from cells. However, the mechanism underlying lncRNA secretion and the functions of circulating miRNAs and lncRNAs have not been fully illuminated. Concurrently, to standardize results of global investigations of circulating miRNAs and lncRNAs biomarker studies, several recommendations for pre-analytic considerations are put forward. In this review, we summarize the known circulating miRNAs and lncRNAs for GC diagnosis. The possible mechanism of miRNA and lncRNA secretion as well as methodologies for identification of circulating miRNAs and lncRNAs are also discussed. The topics covered here highlight new insights into GC diagnosis and screening.

The biology of circulating microRNAs in cardiovascular disease

BACKGROUND

Since their first description in mammalian cells, more than 2500 microRNA molecules have been predicted or verified within human cells. Recently, extracellular microRNAs have been described, protected from degradation by specialized packaging in extracellular vesicles or RNA-binding proteins.

MATERIALS AND METHODS

We will discuss recent data regarding circulating microRNAs, their potential role as novel biomarkers and intercellular communicators, as well as future challenges of studying and applying such novel biology, particularly in the cardiovascular system.

RESULTS

Circulating microRNAs have been proposed as attractive candidates as both diagnostic and prognostic biomarkers in various diseases, including a spectrum of cardiovascular conditions. Moreover, consistent with our evolving appreciation of the role of exosomes and microvesicles in intercellular communication, it has been proposed that delivery of active microRNAs to recipient tissues may serve as a primary mode of intercellular communication. Indeed, the transfer of functional microRNAs has been demonstrated in in vitro models and has been reported in a few in vivo contexts. In addition, therapeutic application of extracellular microRNAs has also been explored.

CONCLUSION

Over recent years, increasing attention has been paid to the role of circulating miRNAs in cardiovascular disease. As biomarkers and intercellular communicators, circulating miRNAs could play important roles in the prediction, diagnosis and tailored treatment of cardiovascular diseases in the near future.

Diagnostic value of a plasma microRNA signature in gastric cancer: a microRNA expression analysis

The differential expression of microRNAs (miRNAs) in plasma of gastric cancer (GC) patients may serve as a diagnostic biomarker. A total of 33 miRNAs were identified through the initial screening phase (3 GC pools vs. 1 normal control (NC) pool) using quantitative reverse transcription polymerase chain reaction (qRT-PCR) based Exiqon panel (miRCURY-Ready-to-Use-PCR-Human-panel-I + II-V1.M). By qRT-PCR, these miRNAs were further assessed in training (30 GC VS. 30 NCs) and testing stages (71 GC VS. 61 NCs). We discovered a plasma miRNA signature including five up-regulated miRNAs (miR-185, miR-20a, miR-210, miR-25 and miR-92b), and this signature was evaluated to be a potential diagnostic marker of GC. The areas under the receiver operating characteristic curve of the signature were 0.86, 0.74 and 0.87 for the training, testing and the external validation stages (32 GC VS. 18 NCs), respectively. The five miRNAs were consistently dysregulated in GC tissues (n = 30). Moreover, miR-185 was decreased while miR-20a, miR-210 and miR-92b were increased in arterial plasma (n = 38). However, none of the miRNAs in the exosomes showed different expression between 10 GC patients and 10 NCs. In conclusion, we identified a five-miRNA signature in the peripheral plasma which could serve as a non-invasive biomarker in detection of GC.

MiR-107 down-regulates SIAH1 expression in human breast cancer cells and silencing of miR-107 inhibits tumor growth in a nude mouse model of triple-negative breast cancer

We have reported that SIAH1 is down-regulated and associated with apoptosis and invasion in human breast cancer. However, the molecular mechanisms leading to SIAH1 down-regulation remain to be elucidated. Here, we demonstrated that miR-107 directly down-regulates SIAH1 expression in human breast cancer cells. Over- expression of miR-107 reduced SIAH1 expression, promoted human breast cancer cell proliferation, colony formation, migration and invasion, and inhibited apoptosis. On the contrary, silencing of miR-107 increased SIAH1 expression and inhibited the tumor growth of MDA-MB-231 cells, a kind of triple-negative breast cancer (TNBC) cells, in vitro and in vivo. Our results reveal that miR-107 is an upstream regulator for SIAH1 down-regulation in human breast cancer cells and miR-107 provides a potential effective target for the treatment of TNBC.

MIR210 as a potential molecular target to block invasion and metastasis of gastric cancer

The epithelial-mesenchymal transition (EMT) is a process driving invasion, recurrence, and metastasis of gastric cancer, and EMT is triggered by specific physiological factors that arise during tumorigenesis, such as hypoxia. Identifying the molecular mechanisms underlying EMT will potentially yield insight into the pathways fueling cancer recurrence and metastasis and thus, lead to novel molecular targets that will improve treatment of the disease. The microRNA210 (MIR210) is such a candidate molecule mediating EMT in gastric cancer based on a number of observations. First, MIR210 is often highly overexpressed in gastric cancer. Second, MIR210 is a hypoxia-specific miRNA, and its expression is significantly increased in hypoxic environments where EMT develops. Third, MIR210 is regulated by hypoxia inducible factor 1α (HIF-1α), a key transcription factor mediating important tumor associated processes such as EMT and angiogenesis in response to hypoxia during tumorigenesis. Finally, MIR210 has been intriguingly associated with Helicobacterpylori infection, which typically develops in an anaerobic environment and is known to have a causal role in the development of gastric cancer. Although studies have shown that MIR210 is often highly expressed in gastric cancer and associated with specific pathological conditions, functional experiments have not yet been performed to determine the role of MIR210 and downstream mediators in the development and progression of gastric cancer. Here, MIR210 is proposed as a viable molecular target in the treatment of gastric cancer, specifically for the inhibition of invasion and metastasis.

MicroRNAs as potential biomarkers for gastric cancer

Gastric cancer is the fourth most common cancer in the world and the second leading cause of cancer-related death. More than 80% of diagnoses occur at the middle to late stage of the disease, highlighting an urgent need for novel biomarkers detectable at earlier stages. Recently, aberrantly expressed microRNAs (miRNAs) have received a great deal of attention as potential sensitive and accurate biomarkers for cancer diagnosis and prognosis. This review summarizes the current knowledge about potential miRNA biomarkers for gastric cancer that have been reported in the publicly available literature between 2008 and 2013. Available evidence indicates that aberrantly expressed miRNAs in gastric cancer correlate with tumorigenesis, tumor proliferation, distant metastasis and invasion. Furthermore, tissue and cancer types can be classified using miRNA expression profiles and next-generation sequencing. As miRNAs in plasma/serum are well protected from RNases, they remain stable under harsh conditions. Thus, potential functions of these circulating miRNAs can be deduced and may implicate their diagnostic value in cancer detection. Circulating miRNAs, as well as tissue miRNAs, may allow for the detection of gastric cancer at an early stage, prediction of prognosis, and monitoring of recurrence and/or lymph node metastasis. Taken together, the data suggest that the participation of miRNAs in biomarker development will enhance the sensitivity and specificity of diagnostic and prognostic tests for gastric cancer.

Serum microRNA-21 as a diagnostic marker for lung carcinoma: a systematic review and meta-analysis

Objectives

MicroRNA-21 in serum is a promising marker for the diagnosis of lung carcinoma. A meta-analysis was performed to assess the diagnostic accuracy and clinical value of serum microRNA-21 in patients with lung carcinoma.

Methods

PubMed, EMBASE, Web of Knowledge (ISI), the Cochrane Library, Scopus, BioMed Central, Science Direct, China National Knowledge Infrastructure (CNKI), Wan Fang data and Technology of Chongqing (VIP) databases were searched to identify studies in English and Chinese that assessed the diagnostic value of serum miR-21 for lung carcinoma, from inception to 9 April 2014. Two independent investigators identified and extracted the study characteristics from all articles according to defined inclusion and exclusion criteria. Quality assessment of diagnostic accuracy studies (QUADAS) was used to score the quality of the eligible studies. Stata12 and Meta-DiSc software were used to test the heterogeneity and to perform the meta-analysis.

Results

Our search returned 1008 articles, of which seven fulfilled the inclusion criteria, accounting for 500 patients and 386 controls. Using random-effect model analysis, the summary assessments revealed that the mean sensitivity was 0.71% (95%CI: 57–82%) and specificity was 0.84% (95%CI: 76–89%). The area under the receiver operating characteristic curve was 0.86 (95%CI: 0.83–0.89). In addition, heterogeneity was clearly apparent but was not caused by the threshold effect, as shown by Meta-DiSc analysis.

Conclusion

The current evidence suggests that serum miR-21 can be rapidly measured in lung carcinoma patients and has potential diagnostic value with moderate sensitivity and specificity. Further prospective studies to assess the early stage diagnostic value are needed in the future.

Point-of-care diagnostic tools to detect circulating microRNAS as biomarkers of disease

MicroRNAs or miRNAs are a form of small non-coding RNAs (ncRNAs) of 19–22 nucleotides in length in their mature form. miRNAs are transcribed in the nucleus of all cells from large precursors, many of which have several kilobases in length. Originally identified as intracellular modulators of protein synthesis via posttranscriptional gene silencing, more recently it has been found that miRNAs can travel in extracellular human fluids inside specialized vesicles known as exosomes. We will be referring to this miRNAs as circulating microRNAs. More interestingly, the miRNA content inside exosomes changes during pathological events. In the present review we analyze the literature about circulating miRNAs and their possible use as biomarkers. Furthermore, we explore their future in point-of-care (POC) diagnostics and provide an example of a portable POC apparatus useful in the detection of circulating miRNAs.

Rapid upregulation and clearance of distinct circulating microRNAs after prolonged aerobic exercise

Short nonprotein coding RNA molecules, known as microRNAs (miRNAs), are intracellular mediators of adaptive processes, including muscle hypertrophy, contractile force generation, and inflammation. During basal conditions and tissue injury, miRNAs are released into the bloodstream as "circulating" miRNAs (c-miRNAs). To date, the impact of extended-duration, submaximal aerobic exercise on plasma concentrations of c-miRNAs remains incompletely characterized. We hypothesized that specific c-miRNAs are differentially upregulated following prolonged aerobic exercise. To test this hypothesis, we measured concentrations of c-miRNAs enriched in muscle (miR-1, miR-133a, miR-499-5p), cardiac tissue (miR-208a), and the vascular endothelium (miR-126), as well as those important in inflammation (miR-146a) in healthy male marathon runners (N = 21) at rest, immediately after a marathon (42-km foot race), and 24 h after the race. In addition, we compared c-miRNA profiles to those of conventional protein biomarkers reflective of skeletal muscle damage, cardiac stress and necrosis, and systemic inflammation. Candidate c-miRNAs increased immediately after the marathon and declined to prerace levels or lower after 24 h of race completion. However, the magnitude of change for each c-miRNA differed, even when originating from the same tissue type. In contrast, traditional biomarkers increased after exercise but remained elevated 24 h postexercise. Thus c-miRNAs respond differentially to prolonged exercise, suggesting the existence of specific mechanisms of c-miRNA release and clearance not fully explained by generalized cellular injury. Furthermore, c-miRNA expression patterns differ in a temporal fashion from corollary conventional tissue-specific biomarkers, emphasizing the potential of c-miRNAs as unique, real-time markers of exercise-induced tissue adaptation.

Diagnostic significance of serum eotaxin-1 level in gastric cancer patients

INTRODUCTION

Gastric cancer is the second cause of cancer-related deaths worldwide. Delayed diagnosis leads to high mortality rates. Eotaxin-1 was originally discovered as an eosinophil-selective chemoattractant and may play a role in a number of chronic inflammatory diseases, cancer, and other gastrointestinal disorders. The aim of this study was to analyse diagnostic and prognostic significance of serum eotaxin-1 (s-eotaxin-1) levels in gastric cancer.

METHODS

Sixty gastric cancer patients and 69 healthy subjects were included into the study. S-eotaxin-1 levels were compared with clinicopathological features and outcomes in gastric cancer.

RESULTS

Serum levels of eotaxin-1 in gastric cancer patients were significantly higher than controls (74.51 ± 16.65 pg/mL versus 16.79 ± 5.52 pg/mL, respectively (P < 0.001)). The s-eotaxin-1 levels did not differ significantly with histopathological grade, tumor-node-metastasis (TNM) stage, tumor localization, lymph node metastases, positive lymph node ratio, size, perineural and perivascular invasion. So there is no relationship found between s-eotaxin-1 level and prognosis.

CONCLUSION

S-eotaxin-1 levels may be used as an easily available biomarker for gastric cancer risk and may alert physicians for early diagnosis. Due to the limited number of patients included in this study, larger cohort studies are warranted to validate the diagnostic value of s-eotaxin-1 level in gastric cancer.

Therapeutic targets associated to E-cadherin dysfunction in gastric cancer

INTRODUCTION

Epithelial cadherin (E-cadherin) plays a key role in epithelial cell-cell adhesion, contributing to tissue differentiation and homeostasis. Throughout the past decades, research has shed light on the molecular mechanisms underlying E-cadherin's role in tumor progression, namely in invasion and metastization. Emerging evidence established E-cadherin as a tumor suppressor and suggests that targeting E-cadherin or downstream signaling molecules may constitute effective cancer therapeutics.

AREAS COVERED

This review aims to cover E-cadherin-mediated signaling during cancer development and progression and highlight putative therapeutic targets.

EXPERT OPINION

Reconstitution of E-cadherin expression or targeting of E-cadherin downstream molecules holds promise in cancer therapies. Considering the high frequency of CDH1 promoter hypermethylation as a second hit in malignant lesions from hereditary diffuse gastric cancer patients, histone deacetylase inhibitors are potential therapeutic agents in combination with conventional chemotherapy, specifically in initial tumor stages. Concerning E-cadherin-mediated signaling, we propose that HER receptors (as epidermal growth factor receptor) and Notch downstream targets are clinically relevant and should be considered in gastric cancer therapeutics and control.

Binding of intronic miRNAs to the mRNAs of host genes encoding intronic miRNAs and proteins that participate in tumourigenesis

In this study, we examined 615 host genes encoding 915 in-miRNAs as possible targets for interactions with all in-miRNAs. Host genes whose proteins are involved in esophageal, gastric, small bowel, colorectal, and breast cancer development were studied. Unique in-miRNA binding sites with a significance of p<0.0005 were found in the 5'UTRs, CDSs, and 3'UTRs of the host genes encoding proteins that are key participants in tumourigenesis. These data shed light on the interactions between miRNAs and mRNAs and on the role of candidate proteins in cancer. Therefore, our findings have potential application in the development of diagnostic and treatment methods.

Circulating microRNAs predict biochemical recurrence in prostate cancer patients

Background:

Circulating microRNAs (miRNAs) are emerging as promising biomarkers for prostate cancer. Here, we investigated the potential of these molecules to assist in prognosis and treatment decision-making.

Methods:

MicroRNAs in the serum of patients who had experienced rapid biochemical recurrence (BCR) (n=8) or no recurrence (n=8) following radical prostatectomy (RP) were profiled using high-throughput qRT-PCR. Recurrence-associated miRNAs were subsequently quantitated by qRT-PCR in a validation cohort comprised of 70 patients with Gleason 7 cancers treated by RP, 31 of whom had undergone disease progression following surgery. The expression of recurrence-associated miRNAs was also examined in tumour tissue cohorts.

Results:

Three miRNAs – miR-141, miR-146b-3p and miR-194 – were elevated in patients who subsequently experienced BCR in the screening study. MiR-146b-3p and miR-194 were also associated with disease progression in the validation cohort, as determined by log-rank tests and Cox proportional hazards regression. Multivariate analysis revealed that miR-146b-3p possessed prognostic information beyond standard clinicopathological parameters. Analysis of tissue cohorts revealed that miR-194 was robustly expressed in the prostate, elevated in metastases, and its expression in primary tumours was associated with a poor prognosis.

Conclusion:

Our study suggests that circulating miRNAs, measured at the time of RP, could be combined with current prognostic tools to predict future disease progression in men with intermediate risk prostate cancers.

Methylated DNA and microRNA in body fluids as biomarkers for cancer detection

Epigenetic alterations including DNA methylation and microRNAs (miRNAs) play important roles in the initiation and progression of human cancers. As the extensively studied epigenetic changes in tumors, DNA methylation and miRNAs are the most potential epigenetic biomarkers for cancer diagnosis. After the identification of circulating cell-free nuclear acids, increasing evidence demonstrated great potential of cell-free epigenetic biomarkers in the blood or other body fluids for cancer detection.