Colorectal cancers with microsatellite instability display unique miRNA profiles

Revisiting the diagnostic performance of exosomes: harnessing the feasibility of combinatorial exosomal miRNA profiles for colorectal cancer diagnosis

The challenges associated with liquid biopsy of colorectal cancer (CRC) are closely linked to the substantial variations observed in gene expression profiles among patients. This variability complicates the selection of an ideal biomarker for accurate diagnosis. In this report, we propose that employing a combination of miRNAs offers a better change for enhancing the accuracy of CRC diagnosis compared to solely relying on single miRNAs. As an illustrative example, we measured 9 miRNAs from 45 patient samples (comprising 31 CRC cases and 14 healthy controls) via RT-qPCR. We then utilized two methods: (1) LASSO regression for marker ranking and (2) linear discriminant analysis (LDA) to identify the optimal weighted combination of multiple markers. Our data indicates that combination of triple markers, selected based on their ranking, exhibited the highest diagnostic performance, including a sensitivity of 93.6% (95% confidence interval, CI 79.3-98.9%), specificity of 100% (CI 78.5-100.0%), positive predictive value (PPV) of 100%, negative predictive value (NPV) of 87.5%, and an overall accuracy of 95.6%. In contrast, the diagnostic performance of each individual miRNA used in the triple marker combination ranged from 53.3 to 80.0% in accuracy. While we acknowledge the need for further extensive studies involving larger patient cohorts and the consideration of additional miRNA candidates, our research undeniably highlights the potential of combining multiple markers as a robust methodology for identifying biomarkers among heterogeneous patient profiles.

MicroRNA-206 overexpression is associated with a prominent inflammatory reaction and a favorable colorectal cancer prognosis

BACKGROUND

MicroRNAs act as oncogenes or tumor suppressors in various cancers. The tumor microenvironment (TME) plays an important role in tumor cell progression and survival.

METHODS

MicroRNA expressions were evaluated by using NanoString nCounter assay, qRT-PCR and in situ hybridization. Correlation between MircoRNA expressions and TME factors, clinicopathological behaviors and prognostic significance were assessed in 323 surgically resected colorectal cancers.

RESULTS

The microRNA-206 expression was identified significantly higher in Glasgow microenvironment score (GMS) 0 than in GMS 1 or GMS 2 by using the NanoString nCounter assay and qRT-PCR. High microRNA-206 expression was identified in 155 (48.0 %) cases in in situ hybridization and was significantly correlated with low pT classification, and absence of lymphovascular and perineural invasion, and lymph node metastasis. MicroRNA-206 expression was significantly associated with low tumor stroma percentage (TSP), high Klintrup-Mäkinen (KM) grade and low GMS. Patients with high microRNA-206 expression showed significantly better 5-year overall survival than those with low microRNA-206 expression, and was an independent prognostic factor in patients with colorectal cancer. High miR-206 expression was associated with TME, favorable clinicopathologic behaviors and overall survival and presents an independent prognostic factor in patients with colorectal cancer.

CONCLUSION

Thus, MicroRNA-206 expression presents a feasible prognostic factor and potential therapeutic target to treat patients with colorectal cancer.

microRNA-622 upregulates cell cycle process by targeting FOLR2 to promote CRC proliferation

BACKGROUND

Epigenetic alterations contribute greatly to the development and progression of colorectal cancer, and effect of aberrant miR-622 expression is still controversial. This study aimed to discover miR-622 regulation in CRC proliferation.

METHODS

miR-622 expression and prognosis were analyzed in clinical CRC samples from Nanfang Hospital. miR-622 regulation on cell cycle and tumor proliferation was discovered, and FOLR2 was screened as functional target of miR-622 using bioinformatics analysis, which was validated via dual luciferase assay and gain-of-function and loss-of-function experiments both in vitro and in vivo.

RESULTS

miR-622 overexpression in CRC indicated unfavorable prognosis and it regulated cell cycle to promote tumor growth both in vitro and in vivo. FOLR2 is a specific, functional target of miR-622, which negatively correlates with signature genes in cell cycle process to promote CRC proliferation.

CONCLUSIONS

miR-622 upregulates cell cycle process by targeting FOLR2 to promote CRC proliferation, proposing a novel mechanism and treatment target in CRC epigenetic regulation of miR-622.

The Clinical Significance of MicroRNAs in Colorectal Cancer Signaling Pathways: A Review

Colorectal carcinoma (colon and rectum) is currently considered among the most prevalent malignancies of Western societies. The pathogenesis and etiological mechanisms underlying colorectal cancer (CRC) development remain complex and heterogeneous. The homeostasis and function of normal human intestinal cells is highly regulated by microRNAs. Therefore, it is not surprising that mutations and inactivation of these molecules appear to be linked with progression of colorectal tumors. Recent studies have reported significant alterations of microRNA expression in adenomas and CRCs compared with adjacent normal tissues. This observed deviation has been proposed to correlate with the progression and survival of disease as well as with choice of optimal treatment and drug resistance. MicroRNAs can adopt either oncogenic or tumor-suppressive roles during regulation of pathways that drive carcinogenesis. Typically, oncogenic microRNAs termed oncomirs, target and silence endogenous tumor-suppressor genes. On the other hand, tumor-suppressive microRNAs are critical in downregulating genes associated with cell growth and malignant capabilities. By extensively evaluating robust studies, we have emphasized and distinguished a discrete set of microRNAs that can modulate tumor progression by silencing specific driver genes crucial in signaling pathways including Wnt/b-catenin, epidermal growth factor receptor, P53, mismatch repair DNA repair, and transforming-growth factor beta.

Liquid biopsy-based early tumor and minimal residual disease detection

Genetic predisposition is one of the major measurable cancer risk factors. Affected patients have an enhanced risk for cancer and require life-long surveillance. However, current screening measures are mostly invasive and only available for certain tumor types. Particularly in hereditary cancer syndromes, liquid biopsy, in addition to monitoring therapy response and assessing minimal residual disease, holds great potential for surveillance at the precancerous stage and potentially even diagnostics. Exploring these options and future clinical translation could help reduce cancer risk and mortality in high-risk individuals and enhance patients' adherence to tailored surveillance protocols.

Rebound increase in microRNA levels at the end of 5-FU-based therapy in colorectal cancer patients

Treatment with 5-fluorouracil (5-FU) based therapy is still used for colorectal cancer (CRC). Epigenetics has become a focus of study in cancer because of its reversibility besides its known regulatory functions. In this study, we will monitor the change in microRNAs (miRNAs) levels with 5-FU-based therapy at baseline and after 3 and 6 months of treatment to be correlated with their prognostic potential. The expression levels of 5 miRNAs, namely miRNA223-3p, miRNA20a-5p, miRNA17-5p, miRNA19a-3p, and miRNA7-5p, were measured in the peripheral blood of 77 CRC patients, along with the expression of 3 proteins PTEN, ERK, and EGFR. At baseline, CRC patients had significantly higher levels of circulating miRNAs than healthy controls. This level was reduced after 3 months of 5-FU-based therapy, then increased after 6 months significantly in responder patients compared to non-responders. MiRNA19a-3p showed that significant pattern of change in the subgroups of patients with high ERK, EGFR, and PTEN protein levels, and its 6 months level after 5-FU-based therapy showed significance for the hazard of increased risk of disease recurrence and progression.

Lynch Syndrome Biopathology and Treatment: The Potential Role of microRNAs in Clinical Practice

Lynch syndrome (LS), also known as Hereditary Non-Polyposis Colorectal Cancer (HNPCC), is an autosomal dominant cancer syndrome which causes about 2-3% of cases of colorectal carcinoma. The development of LS is due to the genetic and epigenetic inactivation of genes involved in the DNA mismatch repair (MMR) system, causing an epiphenomenon known as microsatellite instability (MSI). Despite the fact that the genetics of the vast majority of MSI-positive (MSI+) cancers can be explained, the etiology of this specific subset is still poorly understood. As a possible new mechanism, it has been recently demonstrated that the overexpression of certain microRNAs (miRNAs, miRs), such as miR-155, miR-21, miR-137, can induce MSI or modulate the expression of the genes involved in LS pathogenesis. MiRNAs are small RNA molecules that regulate gene expression at the post-transcriptional level by playing a critical role in the modulation of key oncogenic pathways. Increasing evidence of the link between MSI and miRNAs in LS prompted a deeper investigation into the miRNome involved in these diseases. In this regard, in this study, we discuss the emerging role of miRNAs as crucial players in the onset and progression of LS as well as their potential use as disease biomarkers and therapeutic targets in the current view of precision medicine.

From Omic Layers to Personalized Medicine in Colorectal Cancer: The Road Ahead

Colorectal cancer is a major health concern since it is a highly diagnosed cancer and the second cause of death among cancers. Thus, the most suitable biomarkers for its diagnosis, prognosis, and treatment have been studied to improve and personalize the prevention and clinical management of colorectal cancer. The emergence of omic techniques has provided a great opportunity to better study CRC and make personalized medicine feasible. In this review, we will try to summarize how the analysis of the omic layers can be useful for personalized medicine and the existing difficulties. We will discuss how single and multiple omic layer analyses have been used to improve the prediction of the risk of CRC and its outcomes and how to overcome the challenges in the use of omic layers in personalized medicine.

Systemic circulating microRNA landscape in Lynch syndrome

Circulating microRNAs (c-miRs) are small noncoding RNA molecules that migrate throughout the body and regulate gene expression. Global c-miR expression patterns (c-miRnomes) change with sporadic carcinogenesis and have predictive potential in early detection of cancers. However, there are no studies that have assessed whether c-miRnomes display similar potential in carriers of inherited pathogenic mismatch-repair gene variants (path_MMR), known as Lynch syndrome (LS), who are predisposed to highly increased cancer risk. Using high-throughput sequencing and bioinformatic approaches, we conducted an exploratory analysis to characterize systemic c-miRnomes of path_MMR carriers, sporadic rectal cancer patients and non-LS controls. We showed for the first time that cancer-free path_MMR carriers have a systemic c-miRnome of 40 differentially expressed c-miRs that can distinguish them from non-LS controls. The systemic c-miRnome of cancer-free path_MMR carriers also resembles the systemic c-miRnomes of cancer patients with or without path_MMR. Our pathway analysis linked the found differentially expressed c-miRs to carcinogenesis. A total of 508 putative target genes were identified for 32 out of 40 differentially expressed c-miRs, and 238 of them were enriched in cancer-related pathways. The most enriched c-miR-target genes include well-known oncogenes and tumor suppressor genes such as BCL2, AKT3, PIK3CA, KRAS, NRAS, CDKN1A and PIK3R1. Taken together, our findings suggest that LS and sporadic carcinogenesis share common biological pathways and alterations in these pathways can produce a c-miR signature which can track potential oncogenic stress in cancer-free path_MMR carriers. Therefore, c-miRs hold potential in monitoring the LS risk stratification patterns during clinical surveillance or cancer management.

Extracellular Nucleic Acids in the Diagnosis and Progression of Colorectal Cancer

Colorectal cancer (CRC) is the 3rd most common malignant neoplasm worldwide, with more than two million new cases diagnosed yearly. Despite increasing efforts in screening, many cases are still diagnosed at a late stage, when mortality is high. This paper briefly reviews known genetic causes of CRC (distinguishing between sporadic and familial forms) and discusses potential and confirmed nucleic acid biomarkers obtainable from liquid biopsies, classified by their molecular features, focusing on clinical relevance. We comment on advantageous aspects such as better patient compliance due to blood sampling being minimally invasive, the possibility to monitor mutation characteristics of sporadic and hereditary CRC in a disease showing genetic heterogeneity, and using up- or down-regulated circulating RNA markers to reveal metastasis or disease recurrence. Current difficulties and thoughts on some possible future directions are also discussed. We explore current evidence in the field pointing towards the introduction of personalized CRC management.

Liquid Biopsy as a Source of Nucleic Acid Biomarkers in the Diagnosis and Management of Lynch Syndrome

Lynch syndrome (LS) is an autosomal dominant inherited cancer predisposition disorder, which may manifest as colorectal cancer (CRC), endometrial cancer (EC) or other malignancies of the gastrointestinal and genitourinary tract as well as the skin and brain. Its genetic cause is a defect in one of the four key DNA mismatch repair (MMR) loci. Testing of patients at risk is currently based on the absence of MMR protein staining and detection of mutations in cancer tissue and the germline, microsatellite instability (MSI) and the hypermethylated state of the MLH1 promoter. If LS is shown to have caused CRC, lifetime follow-up with regular screening (most importantly, colonoscopy) is required. In recent years, DNA and RNA markers extracted from liquid biopsies have found some use in the clinical diagnosis of LS. They have the potential to greatly enhance the efficiency of the follow-up process by making it minimally invasive, reproducible, and time effective. Here, we review markers reported in the literature and their current clinical applications, and we comment on possible future directions.

MiR-509-3p is oncogenic, targets the tumor suppressor PHLPP2, and functions as a novel tumor adjacent normal tissue based prognostic biomarker in colorectal cancer

Background

Recently the role of microRNAs has been explored immensely as novel regulators and potential biomarkers in several cancers. MiR-509-3p is one such miRNA that has been observed to show a mixed expression in different cancers, while it’s expression and clinical relevance in colorectal cancer (CRC) has not yet been characterized.

Methods

We used quantitative PCR to evaluate the expression of miR-509-3p in fresh-frozen CRC tumor tissues and the corresponding tumor-adjacent normal (NAT) tissues from 103 patients. Subsequently, functional studies were performed to further interpret the role of the miRNA in CRC.

Results

MiR-509-3p was found to be overexpressed in CRC tissues in nearly 80% of cases and was associated with an aggressive disease presentation. Notably, a higher expression of the miRNA promoted cell proliferation, migration, and invasion of CRC cells in in vitro and in vivo models. Mechanistically, we confirmed that miR-509-3p directly binds the 3’UTR of the tumor suppressor PHLPP2 and inhibits its expression. Furthermore, within the previous 103 clinical tissue specimens, we observed an overexpression of miR-509-3p within the NAT tissue of patients associated with a poor disease prognosis. Using multivariate analysis, it was observed that the expression of miR-509-3p within the NAT tissue was an independent predictor of prognosis in CRC. At the cellular level, through indirect coculture experiments, miR-509-3p was observed to regulate the proliferative, migratory, and invasive behavior of normal colon cells.

Conclusion

MiR-509-3p strongly contributes to the development and progression of CRC and can potentially function as a prognostic biomarker in the disease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-09075-x.

Circulating MicroRNAs in Relation to Esophageal Adenocarcinoma Diagnosis and Survival

BACKGROUND AND AIMS

Tissue miRNA can discriminate between esophageal adenocarcinoma (EA) and normal epithelium. However, no studies have examined a comprehensive panel of circulating miRNAs in relation to EA diagnosis and survival.

METHODS

We used all 62 EA cases from the US Multi-Center case-control study with available serum matched 1:1 to controls. Cases were followed for vital status. MiRNAs (n = 2064) were assessed using the HTG EdgeSeq miRNA Whole Transcriptome Assay. Differential expression analysis of miRNAs in relation to case-control status was conducted. In cases, Cox regression models were fit to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause mortality. P values were adjusted using the Benjamini-Hochberg (BH) procedure for false discovery rate control. Predictive performance was assessed using cross-validation.

RESULTS

Sixty-eight distinct miRNAs were significantly upregulated between cases and controls (e.g., miR-1255b-2-3p fold change = 1.74, BH-adjusted P = 0.01). Assessing the predictive performance of these significantly upregulated miRNAs yielded 60% sensitivity, 65% specificity, and 0.62 AUC. miR-4253 and miR-1238-5p were associated with risk of mortality after EA diagnosis (HR = 4.85, 95% CI: 2.30-10.23, BH-adjusted P = 0.04 and HR = 3.81, 95% CI: 2.02-7.19, BH-adjusted P = 0.04, respectively).

CONCLUSIONS

While they require replication, these findings suggest that circulating miRNAs may be associated with EA diagnosis and survival.

MicroRNA expression in inflammatory bowel disease-associated colorectal cancer

MicroRNAs (miRNAs) are non-coding RNA molecules composed of 19–25 nucleotides that regulate gene expression and play a central role in the regulation of several immune-mediated disorders, including inflammatory bowel diseases (IBD). IBD, represented by ulcerative colitis and Crohn’s disease, is characterized by chronic intestinal inflammation associated with an increased risk of colorectal cancer (CRC). CRC is one of the most prevalent tumors in the world, and its main risk factors are obesity, physical inactivity, smoking, alcoholism, advanced age, and some eating habits, in addition to chronic intestinal inflammatory processes and the use of immunosuppressants administered to IBD patients. Recent studies have identified miRNAs associated with an increased risk of developing CRC in this population. The identification of miRNAs involved in this tumorigenic process could be useful to stratify cancer risk development for patients with IBD and to monitor and assess prognosis. Thus, the present review aimed to summarize the role of miRNAs as biomarkers for the diagnosis and prognosis of IBD-associated CRC. In the future, therapies based on miRNA modulation could be used both in clinical practice to achieve remission of the disease and restore the quality of life for patients with IBD, and to identify the patients with IBD at high risk for tumor development.

Employing bioinformatics analysis to identify hub genes and microRNAs involved in colorectal cancer

The third leading cause of cancer-related deaths in the world, colorectal cancer (CRC) is a global health issue that should be addressed in both diagnostics and therapeutics to improve patient survival rate. Today, microarray data analysis is increasingly being used as a novel and effective method for classification of malignancies and making prognostic assessments. Built upon the concept of microarray data analysis and aimed at the identification of CRC-associated genes, our study has adopted an integrative analysis for the gene expression patterns of four microarray datasets in gene expression omnibus (GEO) and microRNAs (miRNAs) expression profiles. We downloaded four gene expression profiles, i.e., GSE37182, GSE25070, GSE10950, and GSE113513, miRNAs gene expression profiles and differentially expressed genes (DEGs). We used R software, the DAVID database, protein-protein interaction (PPI) networks, the Cytoscape program and receiver operating characteristic (ROC) curve for data analysis. Out of the four gene expression profiles, a total of 43 common DEGs were identified, including 10 hub genes, SLC26A3, CLCA1, GUCA2A, MS4A12, CLCA4, GUCA2B, KRT20, AQP8, MAOA, and ADH1A, and four differentially expressed miRNAs, miR-552, miR-423-5p, miR-502-3p, and miR-490-5p. The highly enriched modes of the signaling pathways among these DEGs were speculated to be involved in various processes including nitrogen metabolism, mineral absorption, pancreatic secretions, and tyrosine metabolism in Kyoto encyclopedia of genes and genomes (KEGG) database. According to our bioinformatics analysis, the DEGs identified in the present study could be considered as significant hallmarks in the molecular mechanisms of CRC development. Our findings may assist scientists with developing novel strategies not only for prediction of CRC, but also for screening and early diagnosis, and treatment of CRC patients.

MiR-490-3p Silences CDK1 and Inhibits the Proliferation of Colon Cancer Through an LLPS-Dependent miRISC System

Liquid-liquid phase separation (LLPS) is a burgeoning concept in cell biology, which was associated with miRISC machinery. However, most studies about LLPS are based on overexpression of core proteins, which is far away from nature condition of cells, whether miRISC underwent LLPS under biological condition remains unknown. Taking miR-490-3p and its target CDK1 as an example, we revealed without overexpression of any protein components, miRISC functioned in an LLPS-depend manner. We firstly found miRISC has liquid-like properties in colon cancer (CC) cells and could fulfill common LLPS criteria under overexpression condition. Then, RIP was performed to confirm miR-490-3p is actually functioning in miRISC. RT-qPCR, western blot and luciferase assays were performed and found miR-490-3p could significantly decrease expression of CDK1 in both RNA and protein levels. However, without overexpression of miRISC components, when treating CC cells with 1,6-hexanediol(1,6-HD), a widely used LLPS inhibitor, the silence effects of miR-490-3p to CDK1 were totally abolished, no matter in RNA, protein or luciferase levels, suggesting that miRISC functions in an LLPS-depend way under biological condition. In conclusion, we found miR-490-3p could silence CDK1 to inhibit the proliferation of CC cells in an LLPS-depend manner.

MicroRNAs differential expression profile in metastatic colorectal cancer: A pilot study with literature review

BACKGROUND AND OBJECTIVES

Colorectal cancer is still one of the leading causes of cancer-related deaths worldwide and specific tools to improve disease assessment and treatment response are advocated. The aim of this study was to analyze miRNAs expression in metastatic and non-metastatic colorectal cancer, in order to identify reliable biomarkers suitable for prognosis, treatment and patient's monitoring.

MATERIAL AND METHODS

Among 25 patients (mean age 71 ± 12 years; Female/Male: 12/13) submitted to laparoscopic colorectal resection between August 2017 and February 2019, miRNAs were extracted from fresh frozen tissues of solid tumors. Gene expression's analysis arising from microarray technology was performed.

RESULTS

Pathological evaluation identified 15 metastatic patients (8 presenting with stage III and 7 with stage IV cancers) and 10 non-metastatic patients (4 presenting with stage I and 6 stage II cancers). Bioinformatic analysis of solid biopsies revealed 16 miRNAs (11 upregulated and 5 downregulated) differently expressed between metastatic and non-metastatic groups, with three miRNAs (miR-7515, miR-7109-5p and miR-6831-5p) never linked to colorectal cancer before.

CONCLUSIONS

Our study showed an association between miRNAs and metastatic colorectal cancer, suggesting their potential role as biomarkers for tumor management, if confirmed by further studies.

GH and IGF System: The Regulatory Role of miRNAs and lncRNAs in Cancer

Growth hormone (GH) and the insulin-like growth factor (IGF) system are involved in many biological processes and have growth-promoting actions regulating cell proliferation, differentiation, apoptosis and angiogenesis. A recent chapter in epigenetics is represented by microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) which regulate gene expression. Dysregulated miRNAs and lncRNAs have been associated with several diseases including cancer. Herein we report the most recent findings concerning miRNAs and lncRNAs regulating GH and the IGF system in the context of pituitary adenomas, osteosarcoma and colorectal cancer, shedding light on new possible therapeutic targets. Pituitary adenomas are increasingly common intracranial tumors and somatotroph adenomas determine supra-physiological GH secretion and cause acromegaly. Osteosarcoma is the most frequent bone tumor in children and adolescents and was reported in adults who were treated with GH in childhood. Colorectal cancer is the third cancer in the world and has a higher prevalence in acromegalic patients.

Novel miRNA signature for predicting the stage of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer deaths worldwide. Recently, microRNAs (miRNAs) are reported to be altered and act as potential biomarkers in various cancers. However, miRNA biomarkers for predicting the stage of HCC are limitedly discovered. Hence, we sought to identify a novel miRNA signature associated with cancer stage in HCC. We proposed a support vector machine (SVM)-based cancer stage prediction method, SVM-HCC, which uses an inheritable bi-objective combinatorial genetic algorithm for selecting a minimal set of miRNA biomarkers while maximizing the accuracy of predicting the early and advanced stages of HCC. SVM-HCC identified a 23-miRNA signature that is associated with cancer stages in patients with HCC and achieved a 10-fold cross-validation accuracy, sensitivity, specificity, Matthews correlation coefficient, and area under the receiver operating characteristic curve (AUC) of 92.59%, 0.98, 0.74, 0.80, and 0.86, respectively; and test accuracy and test AUC of 74.28% and 0.73, respectively. We prioritized the miRNAs in the signature based on their contributions to predictive performance, and validated the prognostic power of the prioritized miRNAs using Kaplan–Meier survival curves. The results showed that seven miRNAs were significantly associated with prognosis in HCC patients. Correlation analysis of the miRNA signature and its co-expressed miRNAs revealed that hsa-let-7i and its 13 co-expressed miRNAs are significantly involved in the hepatitis B pathway. In clinical practice, a prediction model using the identified 23-miRNA signature could be valuable for early-stage detection, and could also help to develop miRNA-based therapeutic strategies for HCC.

Ectodermal Organ Development Is Regulated by a microRNA-26b-Lef-1-Wnt Signaling Axis

The developmental role of Lef-1 in ectodermal organs has been characterized using Lef-1 murine knockout models. We generated a Lef-1 conditional over-expression (COEL) mouse to determine the role of Lef-1 expression in epithelial structures at later stages of development after endogenous expression switches to the mesenchyme. Lef-1 over expression (OE) in the oral epithelium creates a new dental epithelial stem cell niche that significantly increases incisor growth. These data indicate that Lef-1 expression is switched off in the dental epithelial at early stages to maintain the stem cell niche and regulate incisor growth. Bioinformatics analyses indicated that miR-26b expression increased coinciding with decreased Lef-1 expression in the dental epithelium. We generated a murine model over-expressing miR-26b that targets endogenous Lef-1 expression and Lef-1-related developmental mechanisms. miR-26b OE mice have ectodermal organ defects including a lack of incisors, molars, and hair similar to the Lef-1 null mice. miR-26b OE rescues the Lef-1 OE phenotype demonstrating a critical genetic and developmental role for miR-26b in the temporal and spatial expression of Lef-1 in epithelial tissues. Lef-1 expression regulates Wnt signaling and Wnt target genes as well as cell proliferation mechanisms, while miR-26b OE reduced the levels of Wnt target gene expression. The extra stem cell compartment in the COEL mice expressed Lef-1 suggesting that Lef-1 is a stem cell factor, which was absent in the miR-26b OE/COEL rescue mice. This is the first demonstration of a microRNA OE mouse model that has ectodermal organ defects. These findings demonstrate that the levels of Lef-1 are critical for development and establish a role for miR-26b in the regulation of ectodermal organ development through the control of Lef-1 expression and an endogenous stem cell niche.

Dissimilar Appearances Are Deceptive-Common microRNAs and Therapeutic Strategies in Liver Cancer and Melanoma

: In this review, we summarize the current knowledge on miRNAs as therapeutic targets in two cancer types that were frequently described to be driven by miRNAs-melanoma and hepatocellular carcinoma (HCC). By focusing on common microRNAs and associated pathways in these-at first sight-dissimilar cancer types, we aim at revealing similar molecular mechanisms that are evolved in microRNA-biology to drive cancer progression. Thereby, we also want to outlay potential novel therapeutic strategies. After providing a brief introduction to general miRNA biology and basic information about HCC and melanoma, this review depicts prominent examples of potent oncomiRs and tumor-suppressor miRNAs, which have been proven to drive diverse cancer types including melanoma and HCC. To develop and apply miRNA-based therapeutics for cancer treatment in the future, it is essential to understand how miRNA dysregulation evolves during malignant transformation. Therefore, we highlight important aspects such as genetic alterations, miRNA editing and transcriptional regulation based on concrete examples. Furthermore, we expand our illustration by focusing on miRNA-associated proteins as well as other regulators of miRNAs which could also provide therapeutic targets. Finally, design and delivery strategies of miRNA-associated therapeutic agents as well as potential drawbacks are discussed to address the question of how miRNAs might contribute to cancer therapy in the future.

Integrated Analysis Identifies a Nine-microRNA Signature Biomarker for Diagnosis and Prognosis in Colorectal Cancer

BACKGROUND

Colorectal cancer (CRC) is the third most lethal and malignant type of cancer in the world. Abnormal expression of human microRNA-200a (hsa-miRNA-200a or miR-200a) has previously been characterized as a clinically noticeable biomarker in several cancers, but its role in CRC is still unclear.

METHODS

Three CRC miRNA expression datasets were integratively analyzed by Least Absolute Shrinkage and Selector Operation (LASSO) and Support Vector Machine-Recursive Feature Elimination (SVM-RFE) algorithms. Nine candidate miRNAs were identified and validated for diagnostic and prognostic capability with the prediction model. The potential roles of the tumor suppressor miR-200a-3p in invasion, migration, and epithelial-mesenchymal transition of CRC cells were elaborated by in vitro studies.

RESULTS

Nine miRNAs (miR-492, miR-200a, miR-338, miR-29c, miR-101, miR-148a, miR-92a, miR-424, and miR-210) were identified as potentially useful diagnostic biomarkers in the clinic. The overall accuracy rate of the nine miRNAs in the diagnostic model was 0.94, 0.89, and 0.978 in the testing, validation, and independent validation dataset, respectively. CRC patients in the GSE29622 cohort were separated by the prognostic model into the low-risk score group and the high-risk score group. The area under the receiver operating characteristic curve (AUC) was 0.872 and 0.783 for predicting the 1- to 10-year survival of CRC patients. The performance of the prognostic model was validated by an independent TCGA-Colon Adenocarcinoma (COAD) dataset with AUC values between 0.911 and 0.796 in predicting 1- to 10-year survival. Nomograms comprising risk scores, tumor stage, and TNM staging were generated for predicting 1-, 3-, and 5-year overall survival (OS) in the GSE29622 and TCGA-COAD datasets. Colony formation, invasion, and migration in DLD1 and SW480 cells were suppressed by overexpression of miR-200a-3p. Inhibition of miR-200a-3p function contributed to abnormal colony formation, migration, invasion, and epithelial-mesenchymal transition (EMT). miR-200a-3p binding sites were located within the 3'-untranslated region (3'-UTR) of the Forkhead box protein A1 (FOXA1) mRNA.

CONCLUSION

We developed and validated a diagnostic and prognostic prediction model for CRC. miR-200a-3p was determined to be a potential diagnostic and prognostic biomarker for CRC.

Potential role of plasma miR-21 and miR-92a in distinguishing between irritable bowel syndrome, ulcerative colitis, and colorectal cancer

AIM

This study aimed to investigate whether plasma miR-21 and miR-92a levels may be used to differentiate between patients with irritable bowel syndrome (IBS), ulcerative colitis (UC), and colorectal cancer (CRC).

BACKGROUND

miRNA expression profiles are well characterized in CRC, but these expression profiles in UC and IBS remain promising. Screening of high-risk individuals for these diseases has substantial clinical benefits.

METHODS

This was a case-control study. We quantified plasma miR-21 and miR-92a expression levels in 100 samples (37 with active UC, 33 with CRC, and 30 with IBS as well as 30 healthy controls) using real-time PCR. Their diagnostic performance for discriminating these diseases was assessed using receiver-operation characteristic curve (AUC-ROC).

RESULTS

The studied miRNAs were differentially expressed among all participated groups. Plasma miR-21 and miR-92a levels exhibited significant upregulation in CRC as compared to IBS, UC, and healthy subjects. Both miRNAs were upregulated in the UC group as compared to IBS and healthy subjects. ROC analysis revealed promising diagnostic performance for miR-21 and miR-92a in discriminating UC from non-UC groups (IBS and healthy subjects) with AUCs of 0.844 and 0.979 respectively. It also distinguished between CRC and UC with AUCs of 0.968 and 0.887 respectively and with reasonable sensitivities and specificities.

CONCLUSION

Circulating miR-21 and miR-92a can be exploited not only as potential noninvasive biomarkers for detection of CRC, but also for differentiation between functional and organic colorectal disorders.

A novel circular RNA, hsa-circ-0000211, promotes lung adenocarcinoma migration and invasion through sponging of hsa-miR-622 and modulating HIF1-α expression

Recently, several studies have evaluated the role of circular RNAs in the metastasis and development of multiple cancers. In our earlier microarray-based study, we had reported the aberrant expression of a novel circular RNA, hsa-circ-0000211 in lung adenocarcinoma (LAC) tissues. However, the roles of hsa-circ-0000211 in LAC have not been studied. Here hsa-circ-0000211 expression in the LAC tissues and cell lines was determined by quantitative real-time PCR (qRT-PCR). The function of hsa-circ-0000211 was evaluated by transwell assay and wound healing. Mechanisms of hsa-circ-0000211 was measured by luciferase reporter assay and western blot. Results revealed the expression of hsa-circ-0000211 in the human LAC tissues and LAC cell lines was higher than that in normal tissue and human lung normal epithelial cells, respectively. The knockdown of hsa-circ-0000211 could inhibit the migration and invasion properties of LAC. Furthermore, hsa-circ-0000211 promoted the migration and invasion of LAC by sponging miR-622. Moreover, hsa-circ-0000211 upregulated the HIF1-α expression by targeting miR-622. hsa-circ-0000211 promoted LAC cell migration and invasion by modulating the miR-622/HIF1-α network. Our study demonstrated that hsa-circ-0000211 can be a potential novel therapeutic target for LAC.

Novel Molecular Characterization of Colorectal Primary Tumors Based on miRNAs

microRNAs (miRNA) expression in colorectal (CR) primary tumours can facilitate a more precise molecular characterization. We identified and validated a miRNA profile associated with clinical and histopathological features that might be useful for patient stratification. In situ hybridization array using paraffin-embedded biopsies of CR primary tumours were used to screen 1436 miRNAs. 17 miRNAs were selected for validation by quantitative reverse transcription polymerase chain reaction (qRT-PCR) (n = 192) and were further correlated with clinical and histopathological data. We demonstrated that miRNAs associated to Colorectal Cancer (CRC) diagnosis age (over 50s and 60s) included miR-1-3p, miR-23b-3p, miR-27b-3p, miR-143-3p, miR-145-5p and miR-193b-5p. miR-23b-3p and miR-24-3p discriminated between Lynch Syndrome and sporadic CRC. miR-10a-5p, miR-20a-5p, miR-642b and Let-7a-5p were associated to stroma abundance. miR-642b and Let-7a-5p were associated with to peritumoral inflammation abundance. miR-1-3p, miR-143-3p and miR-145-5p correlated with mucinous component. miR-326 correlated with tumour location (right or left sided). miR-1-3p associated with tumour grade. miR-20a-5p, miR-193b-5p, miR-320a, miR-326 and miR-642b-3p associated to tumour stage and progression. Remarkably, we also demonstrated that miR-1-3p and miR-326 expression significantly associated with patient overall survival (OS). Hierarchical clustering and bioinformatics analysis indicated that selected miRNAs could re-classify the patients and work cooperatively, modulating common target genes involved in colorectal cancer key signalling pathways. In conclusion, molecular characterization of CR primary tumours based on miRNAs could lead to more accurate patient reclassification and may be useful for efficient patient management.

Small RNA expression from viruses, bacteria and human miRNAs in colon cancer tissue and its association with microsatellite instability and tumor location

BACKGROUND

MicroRNAs (miRNA) and other small RNAs are frequently dysregulated in cancer and are promising biomarkers for colon cancer. Here we profile human, virus and bacteria small RNAs in normal and tumor tissue from early stage colon cancer and correlate the expression with clinical parameters.

METHODS

Small RNAs from colon cancer tissue and adjacent normal mucosa of 48 patients were sequenced using Illumina high-throughput sequencing. Clinical parameters were correlated with the small RNA expression data using linear models. We performed a meta-analysis by comparing publicly available small RNA sequencing datasets with our original sequencing data to confirm the main findings.

RESULTS

We identified 331 differentially expressed miRNAs between tumor and normal samples. We found that the major changes in miRNA expression between left and right colon are due to miRNAs located within the Hox-developmental genes, including miR-10b, miR-196b and miR-615. Further, we identified new miRNAs associated with microsatellite instability (MSI), including miR-335, miR-26 and miR-625. We performed a meta-analysis on all publicly available miRNA-seq datasets and identified 117 common miRNAs that were differentially expressed between tumor and normal tissue. The miRNAs miR-135b and miR-31 were the most significant upregulated miRNA in tumor across all datasets. The miRNA miR-133a was the most strongly downregulated miRNA in our dataset and also showed consistent downregulation in the other datasets. The miRNAs associated with MSI and tumor location in our data showed similar changes in the other datasets. Finally, we show that small RNAs from Epstein-Barr virus and Fusobacterium nucleatum are differentially expressed between tumor and normal adjacent tissue.

CONCLUSIONS

Small RNA profiling in colon cancer tissue revealed novel RNAs associated with MSI and tumor location. We show that Fusobacterium nucleatum are detectable at the RNA-level in colon tissue, and that both Fusobacterium nucleatum and Epstein-Barr virus separate tumor and normal tissue.

Transfer of Extracellular Vesicle-Associated-RNAs Induces Drug Resistance in ALK-Translocated Lung Adenocarcinoma

Anaplastic lymphoma kinase (ALK) translocation is an actionable mutation in lung adenocarcinoma. Nonetheless tumour consists of heterogeneous cell subpopulations with diverse phenotypes and genotypes, and cancer cells can actively release extracellular vesicles (EVs) to modulate the phenotype of other cells in the tumour microenvironment. We hypothesized that EVs derived from a drug-resistant subpopulation of cells could induce drug resistance in recipient cells. We have established ALK-translocated lung adenocarcinoma cell lines and subclones. The subclones have been characterized and the expression of EV-RNAs determined by quantitative polymerase chain reaction. The effects of EV transfer on drug resistance were examined in vitro. Serum EV-RNA was assayed serially in two patients prescribed ALK-tyrosine kinase inhibitor (ALK-TKI) treatment. We demonstrated that the EVs from an ALK-TKI-resistant subclone could induce drug resistance in the originally sensitive subclone. EV-RNA profiling revealed that miRNAs miR-21-5p and miR-486-3p, and lncRNAs MEG3 and XIST were differentially expressed in the EVs secreted by the resistant subclones. These circulating EV-RNA levels have been found to correlate with disease progression of EML4-ALK-translocated lung adenocarcinoma in patients prescribed ALK-TKI treatment. The results from this study suggest that EVs released by a drug-resistant subpopulation can induce drug resistance in other subpopulations and may sustain intratumoural heterogeneity.

Small RNA sequencing of sessile serrated polyps identifies microRNA profile associated with colon cancer

Sessile serrated adenoma/polyps (SSA/Ps) of the colon account for 20-30% of all colon cancers. Small non-coding RNAs, including microRNAs (miRNAs), may function as oncogenes or tumor suppressor genes involved in cancer development. Small RNA sequencing (RNA-seq) was used to characterize miRNA profiles in SSA/Ps, hyperplastic polyps (HPs), adenomatous polyps and paired uninvolved colon. Our 108 small RNA-seq samples' results were compared to small RNA-seq data from 212 colon cancers from the Cancer Genome Atlas. Twenty-three and six miRNAs were differentially expressed in SSA/Ps compared to paired uninvolved colon and HPs, respectively. Differential expression of MIR31-5p, MIR135B-5p and MIR378A-5p was confirmed by RT-qPCR. SSA/P-specific miRNAs are similarly expressed in colon cancers containing genomic aberrations described in serrated cancers. Correlation of miRNA expression with consensus molecular subtypes suggests more than one subtype is associated with the serrated neoplasia pathway. Canonical pathway analysis suggests many of these miRNAs target growth factor signaling pathways.

Integrated analysis of colorectal cancer microRNA datasets: identification of microRNAs associated with tumor development

Colorectal cancer (CRC) is one of the leading cause of cancer death worldwide. Currently, no effective early diagnostic biomarkers are available for colorectal carcinoma. Therefore, there is a need to discover new molecules able to identify pre-cancerous lesions. Recently, microRNAs (miRNAs) have been associated with the onset of specific pathologies, thus the identification of miRNAs associated to colorectal cancer may be used to detect this pathology at early stages. On these bases, the expression levels of miRNAs were analyzed to compare the miRNAs expression levels of colorectal cancer samples and normal tissues in several miRNA datasets. This analysis revealed a group of 19 differentially expressed miRNAs. To establish the interaction between miRNAs and the most altered genes in CRC, the mirDIP gene target analysis was performed in such group of 19 differentially expressed miRNAs. To recognize miRNAs able to activate or inhibit genes and pathways involved in colorectal cancer development DIANA-mirPath prediction analysis was applied. Overall, these analyses showed that the up-regulated hsa-miR-183-5p and hsa-miR-21-5p, and the down-regulated hsa-miR-195-5p and hsa-miR-497-5p were directly related to colorectal cancer through the interaction with the Mismatch Repair pathway and Wnt, RAS, MAPK, PI3K, TGF-β and p53 signaling pathways involved in cancer development.

A four-microRNA classifier as a novel prognostic marker for tumor recurrence in stage II colon cancer

About 20 percent of TNM-stage II colon cancer patients who are treated by surgical resection develop recurrence, and adjuvant chemotherapy in this group is still debated among researchers and clinicians. Currently, adverse histopathological and clinical factors are used to select patients for adjuvant chemotherapy following surgery. However, additional biomarkers to classify patients at risk of recurrence are needed. We have conducted a study using fresh frozen tumor tissue from 54 TNM-stage II colon cancer patients and performed microRNA profiling using next-generation sequencing. For the selection of the prognostic microRNAs, a LASSO Cox Regression model was employed. For the validation, we used the publically available TCGA-COAD cohort (n = 122). A prognostic panel of four micorRNAs (hsa-miR-5010-3p, hsa-miR-5100, hsa-miR-656-3p and hsa-miR-671-3p) was identified in the study cohort and validated in the TCGA-COAD cohort. The four-microRNA classifier successfully identified high-risk patients in the study cohort (P < 0.001) and the validation cohort (P = 0.005). Additionally, a number of established risk factors and the four-miRNA classifier were used to construct a nomogram to evaluate risk of recurrence. We identified a four-microRNA classifier in patients with TNM-stage II colon cancer that can be used to discriminate between patients at low- and high risk of recurrence.

MicroRNA-622 is a novel mediator of tumorigenicity in melanoma by targeting Kirsten rat sarcoma

The network of molecular players is similar when comparing neural crest-derived, actively migrating melanoblasts to melanoma cells. However, melanoblasts are sensitive to differentiation-initiating signals at their target site (epidermis), while melanoma cells maintain migratory and undifferentiated features. We aimed at identifying downregulated genes in melanoma that are particularly upregulated in melanoblasts. Loss of such genes could contribute to stabilization of a dedifferentiated, malignant phenotype in melanoma. We determined that microRNA-622 (miR-622) expression was strongly downregulated in melanoma cells and tissues compared to melanocytes and melanoblast-related cells. miR-622 expression correlated with survival of patients with melanoma. miR-622 re-expression inhibited clonogenicity, proliferation, and migration in melanoma. Inhibition of miR-622 in melanocytes induced enhanced migration. Kirsten rat sarcoma (KRAS) was identified as a major functional target of miR-622 in melanoma. We conclude that miR-622 is a novel tumor suppressor in melanoma and identify the miR-622-KRAS axis as potential therapeutic target.

Identification of serum miR-139-3p as a non-invasive biomarker for colorectal cancer

Aberrant levels of circulating microRNAs are potential biomarkers for the early detection of colorectal cancer. The aim of this study was to study miR-139-3p and miR-622 in serum as a non-invasive biomarker for colorectal cancer diagnosis. We applied quantitative polymerase chain reaction to determine the levels of miR-139-3p and miR-622 in 42 pairs of tumor and adjacent non-tumor tissues, and in serum samples of 117 patients and 90 control subjects. Our results showed that miR-139-3p was silenced whereas miR-622 was overexpressed in colorectal cancer. Similarly, serum miR-139-3p level was significantly lower in colorectal cancer patients than in control subjects whereas miR-622 was more frequently detectable in patients. ROC analysis showed that AUC of miR-139-3p was 0.9935, with a sensitivity of 96.6% and specificity of 97.8%. Serum miR-139-3p level showed high sensitivity and specificity for both early and late stage CRCs and proximal and distal CRCs. Detectable serum miR-622 showed a sensitivity of 87.5% and specificity of 63.5% for discriminating CRC patients, but the sensitivity dropped for late stage patients (72.7%). We also included analyses of the blood CEA level for comparing the diagnostic performance of these blood-based biomarkers. The median level in CRC patients (3.6 ng/ml) was significantly higher than that in control (1.8 ng/ml). The AUC value of CEA in diagnosing CRC patients was 0.7515. CEA showed a positive correlation with tumor stage and age of patients and its level was higher in male. Collectively, serum miR-139-3p has strong potential as a promising non-invasive biomarker in colorectal cancer detection.

Expression of microRNAs in the ascites of patients with peritoneal carcinomatosis and peritonitis

BACKGROUND

Peritoneal carcinomatosis (PCA) has a prognostic role in patients with gastrointestinal cancers. The differential diagnosis may be challenging due to the low sensitivity of cytology. Although microRNAs (miRNAs) have been a focus of various specimens and diseases, to the best of the authors' knowledge only limited knowledge exists regarding ascites. Herein, the authors systematically evaluated preanalytical factors and the potential of miRNAs as biomarkers of ascites.

METHODS

The authors prospectively analyzed samples from patients with PCA, spontaneous bacterial peritonitis (SBP), and portal hypertension (no SBP/PCA). Various preanalytical factors such as extraction kits, sample storage, stability, and processing were systematically evaluated. MiRNA expression profiling using TaqMan Low Density Array and quantitative reverse transcriptase-polymerase chain reaction were used to evaluate miRNA expression.

RESULTS

All selected miRNAs were found to be reliably detectable in ascites samples. Ascites miRNAs were well preserved from degradation with required short-term and long-term stability. MiRNA expression profiling in patients with PCA compared with those with no SBP/PCA revealed miR-21, miR-186, miR-222, and miR-483-5p to be upregulated and miR-26b to be downregulated. MiRNA expression validation analysis confirmed higher expression levels of miR-21 and miR-186 in patients with PCA compared with those with no SBP/PCA, whereas miR-223 was significantly upregulated in patients with SBP. A simple proportion score between miR-21 and miR-223 allowed the authors to discriminate between the patients with PCA and those with SBP with an area under the curve of 0.982 (95% confidence interval, 0.943-1.022).

CONCLUSIONS

The data from the current study provide novel evidence of the differential expression of miRNAs in ascites from patients with PCA and SBP, which may offer an additional miRNA-based molecular approach for the differential diagnosis of PCA. Cancer Cytopathol 2018;126:353-63. © 2018 American Cancer Society.

Decoding colorectal cancer epigenomics

Colorectal cancer (CRC) is very heterogeneous and presents different types of epigenetic alterations including DNA methylation, histone modifications and microRNAs. These changes are considered as characteristics of various observed clinical phenotypes. Undoubtedly, the discovery of epigenetic pathways with novel epigenetic-related mechanisms constitutes a promising advance in cancer biomarker discovery. In this review, we provide an evidence-based discussing of the current understanding of CRC epigenomics and its role in initiation, epithelial-to-mesenchymal transition and metastasis. We also discuss the recent findings regarding the potential clinical perspectives of these alterations as potent biomarkers for CRC diagnosis, prognosis, and therapy in the era of liquid biopsy.

miR-1290 Contributes to Colorectal Cancer Cell Proliferation by Targeting INPP4B

Colorectal cancer (CRC) is one of the most common oncological conditions worldwide, to date. MicroRNA-1290 (miR-1290) has been demonstrated to regulate its progression. We studied the role of miR-1290 in CRC progression. The gene was upregulated in CRC tissues and cells. Its overexpression promoted CRC cell proliferation analyzed by MTT assay, colony formation assay, and soft agar growth assay. In addition, miR-1290 knockdown inhibited CRC cell proliferation. We also found that miR-1290 overexpression reduced the p27 level and increased cyclin D1 at both the mRNA and protein levels, whereas miR-1290 knockdown increased p27 and reduced cyclin D1, confirming miR-1290 promoted CRC cell proliferation. Inositol polyphosphate 4-phosphatase B (INPP4B) was the target of miR-1290. Luciferase reporter assay revealed that miR-1290 directly bound to the 3′-UTR of INPP4B; the mutated seed sites in miR-1290 abrogated this effect. Double knockdown of INPP4B and miR-1290 promoted CRC cell proliferation, suggesting miR-1290 promoted CRC cell proliferation by targeting INPP4B.

Different miR-21-3p isoforms and their different features in colorectal cancer

MiR-21, the only microRNA (miRNA) found to be overexpressed in any type of solid tumor, its guide stand, miR-21-5p, has been studied a lot in colorectal cancer (CRC); however, few researchers focused on its passenger strand, miR-21-3p. In our study, based on The Cancer Genome Atlas (TCGA) data, we found that there were more varieties and quantities of miR-21-3p isoforms in microsatellite instability (MSI)-type CRC. We further examined the role of miR-21-3p by in vitro and in vivo studies. MiR-21-3p may be an oncogene in CRC by promoting cellular mobility through epithelial-mesenchymal transition. However, different isoforms, especially miR-21-3p 0 | 2, may be a favorable prognostic marker for CRC survival, probably due to increased complementary effect of miR-21-5p and/or target genes. Further study investigating the underlying mechanism of miRNA isoforms is needed.

Potential roles of microRNAs and ROS in colorectal cancer: diagnostic biomarkers and therapeutic targets

As one of the most commonly diagnosed cancers worldwide, colorectal adenocarcinoma often occurs sporadically in individuals aged 50 or above and there is an increase among younger patients under 50. Routine screenings are recommended for this age group to improve early detection. The multifactorial etiology of colorectal cancer consists of both genetic and epigenetic factors. Recently, studies have shown that the development and progression of colorectal cancer can be attributed to aberrant expression of microRNA. Reactive oxygen species (ROS) that play a key role in cancer cell survival, can also lead to carcinogenesis and cancer exacerbations. Given the rapid accumulating knowledge in the field, an updated review regarding microRNA and ROS in colorectal cancer is necessary. An extensive literature search has been conducted in PubMed/Medline databases to review the roles of microRNAs and ROS in colorectal cancer. Unique microRNA expression in tumor tissue, peripheral blood, and fecal samples from patients with colorectal cancer is outlined. Therapeutic approaches focusing on microRNA and ROS in colorectal cancer treatment is also delineated. This review aims to summarize the newest knowledge on the pathogenesis of colorectal cancer in the hopes of discovering novel diagnostic biomarkers and therapeutic techniques.

miR612 is associated with esophageal squamous cell carcinoma development and metastasis, mediated through TP53

MicroRNAs (miRNAs) serve an important role in the regulation of gene expression. In the present study, differential expressions of miRNAs were compared between esophageal squamous cell carcinoma (ESCC) tissues and normal esophageal tissues. In combination with miRNA target prediction databases, a significantly increased expression of miR-612 was discovered in ESCC. The relationship between miR-612 and TP53 gene expression and their roles in ESCC invasion and metastasis was further studied by reverse transcription-quantitative polymerase chain reaction and western blotting in EC109 cells and cancer tissues. The EC109 cell invasion and migration were significantly reduced after miR-612 expression was inhibited. The levels of wild type TP53 protein and mRNA were lower in ESCC tissues compared to the normal esophageal epithelium. In addition, the mRNA and protein expression levels were reported as downregulated further in tumors with metastasis than in tumors without. In conclusion, miR-612 is identified as associated with ESCC development and metastasis, likely through the regulation of TP53 expression, which could be a potential therapeutic target.

Epigenetics in endometrial carcinogenesis - part 2: histone modifications, chromatin remodeling and noncoding RNAs

Carcinogenesis is a multistep multifactorial process that involves the accumulation of genetic and epigenetic alterations. In the past two decades, there has been an exponential growth of knowledge establishing the importance of epigenetic changes in cancer. Our work focused on reviewing the main role of epigenetics in the pathogenesis of endometrial carcinoma, highlighting the reported results concerning each epigenetic mechanistic layer. In a previous review, we assessed DNA methylation alterations. The present review examines the contribution of histone modifications, chromatin remodeling and noncoding RNA alterations for endometrial carcinogenesis.

Decrease of miR-622 expression suppresses migration and invasion by targeting regulation of DYRK2 in colorectal cancer cells

Background

More and more evidence indicates that microRNAs are present and involved in many tumor-related diseases. The function of microRNA-622 (miR-622) in colorectal cancer (CRC) remains controversial. Dual specificity tyrosine phosphorylation-regulated kinase 2 (DYRK2) has been reported as a tumor suppressor gene in different cancers. The detailed regulation mechanism of DYRK2 in CRC remains unclear.

Methods

miR-622 and DYRK2 expression levels were detected at tissue and cellular level respectively by using real time polymerase chain reaction (PCR), Western blot, and immunohistochemical staining. Pearson’s correlation analysis was used to evaluate the correlation between miR-622 and DYRK2. Transwell assay was applied to measure the effect of miR-622 on migration and invasion of SW1116 and SW480. We used dual luciferase reporter assay to confirm the targeted binding effect of miR-622 and DYRK2 3′-untranslated region (3′UTR). An antisense experiment was executed to further confirm the role miR-622 had played with regard to migration and invasion by targeting regulation of DYRK2 pathway in CRC cells.

Results

In our research, we found that the expression of miR-622 was elevated in CRC tissues and cell lines compared to that of nonCRC tissues and the normal human colon epithelial cell line NCM460. Correspondingly, the expression of DYRK2 in CRC tissues and cell lines showed a contrary tendency. The different expression level of DYRK2 was closely correlated with clinicopathological characteristics of CRC patients. We demonstrated that down-regulation of miR-622 could inhibit the ability of migration and invasion of CRC cell lines SW1116 and SW480. Also, we confirmed that DYRK2 was negatively regulated by miR-622 via a specific targeted binding site within the 3′UTR. We finally verified that the migration and invasion ability of CRC cells in the conducted DYRK2 3′UTR defect plasmid transfection group were lower compared to miR-622 and cotransfection group.

Conclusion

The findings of this study indicate that a decrease of miR-622 expression could suppress migration and invasion by targeting regulation of DYRK2 and miR-622/DYRK2 could be a potential molecular treating target of CRC.

Colorectal adenoma and carcinoma specific miRNA profiles in biopsy and their expression in plasma specimens

BACKGROUND

MiRNA expression markers are well characterized in colorectal cancer (CRC), but less is known about miRNA expression profiles in colorectal adenomas. Genome-wide miRNA and mRNA expression analyses were conducted through the colorectal adenoma dysplasia sequence. Furthermore, analysis of the expression levels of miRNAs in matched plasma samples was performed, focusing on biomarker candidates; miRNA and mRNA expression analyses were performed on colorectal biopsies and plasma samples (20 normals; 11 tubular and 9 tubulovillous adenomas; 20 colorectal carcinomas) by miRNA 3.0 and Human Transcriptome Array (Affymetrix) and validated by RT-qPCR. Microarray data were analyzed using Expression Console and mRNA targets were predicted using miRWALK 2.0.

RESULTS

Based on microarray analysis, 447 miRNAs were expressed in tissue and 320 in plasma. Twelve were upregulated (miR-31, 8-fold p < 0.001) and 11 were downregulated (miR-10b 3-fold p < 0.001) in neoplastic lesions compared to normal group. Eleven miRNAs showed altered expression between adenoma subtypes (miR-183 2.8-fold change, p < 0.007). Expression level of 24 miRNAs differed between adenoma and CRC groups (including miR-196a, 3.5-fold). Three miRNAs (miR-31, miR-4506, miR-452*) were differentially expressed in adenoma compared to normal both in tissue and plasma samples. miRNA expression data were confirmed by RT-PCR both in plasma and matched tissue samples.

CONCLUSIONS

MiRNAs showed characteristic expression changes during CRC development in tissue. miRNAs were also presented in plasma and positively correlated with matched tissue expression levels. The identified miRNA expression changes could be verified RT-PCR methods facilitating routine application.

Sox2 and Lef-1 interact with Pitx2 to regulate incisor development and stem cell renewal

Sox2 marks dental epithelial stem cells (DESCs) in both mammals and reptiles, and in this article we demonstrate several Sox2 transcriptional mechanisms that regulate dental stem cell fate and incisor growth. Conditional Sox2 deletion in the oral and dental epithelium results in severe craniofacial defects, including impaired dental stem cell proliferation, arrested incisor development and abnormal molar development. The murine incisor develops initially but is absorbed independently of apoptosis owing to a lack of progenitor cell proliferation and differentiation. Tamoxifen-induced inactivation of Sox2 demonstrates the requirement of Sox2 for maintenance of the DESCs in adult mice. Conditional overexpression of Lef-1 in mice increases DESC proliferation and creates a new labial cervical loop stem cell compartment, which produces rapidly growing long tusk-like incisors, and Lef-1 epithelial overexpression partially rescues the tooth arrest in Sox2 conditional knockout mice. Mechanistically, Pitx2 and Sox2 interact physically and regulate Lef-1, Pitx2 and Sox2 expression during development. Thus, we have uncovered a Pitx2-Sox2-Lef-1 transcriptional mechanism that regulates DESC homeostasis and dental development.

microRNA-622 acts as a tumor suppressor in hepatocellular carcinoma

microRNAs (miRNAs) are important regulators of tumor development and progression. In this study, we aimed to explore the expression and role of miR-622 in hepatocellular carcinoma (HCC). We found that miR-622 was significantly downregulated in human HCC specimens compared to adjacent noncancerous liver tissues. miR-622 downregulation was significantly associated with aggressive parameters and poor prognosis in HCC. Enforced expression of miR-622 significantly decreased the proliferation and colony formation and induced apoptosis of HCC cells. In vivo studies demonstrated that miR-622 overexpression retarded the growth of HCC xenograft tumors. Bioinformatic analysis and luciferase reporter assays revealed that miR-622 directly targeted the 3'-untranslated region (UTR) of mitogen-activated protein 4 kinase 4 (MAP4K4) mRNA. Ectopic expression of miR-622 led to a significant reduction of MAP4K4 expression in HCC cells and xenograft tumors. Overexpression of MAP4K4 partially restored cell proliferation and colony formation and reversed the induction of apoptosis in miR-622-overexpressing HCC cells. Inhibition of JNK and NF-κB signaling phenocopied the anticancer effects of miR-622 on HCC cells. Taken together, miR-622 acts as a tumor suppressor in HCC and restoration of miR-622 may provide therapeutic benefits in the treatment of HCC.

Molecular Biomarkers of Colorectal Cancer and Cancer Disparities: Current Status and Perspective

This review provides updates on the efforts for the development of prognostic and predictive markers in colorectal cancer based on the race/ethnicity of patients. Since the clinical consequences of genetic and molecular alterations differ with patient race and ethnicity, the usefulness of these molecular alterations as biomarkers needs to be evaluated in different racial/ethnic groups. To accomplish personalized patient care, a combined analysis of multiple molecular alterations in DNA, RNA, microRNAs (miRNAs), metabolites, and proteins in a single test is required to assess disease status in a precise way. Therefore, a special emphasis is placed on issues related to utility of recently identified genetic and molecular alterations in genes, miRNAs, and various "-omes" (e.g., proteomes, kinomes, metabolomes, exomes, methylomes) as candidate molecular markers to determine cancer progression (disease recurrence/relapse and metastasis) and to assess the efficacy of therapy in colorectal cancer in relation to patient race and ethnicity. This review will be useful for oncologists, pathologists, and basic and translational researchers.

Hsa-miR-137, hsa-miR-520e and hsa-miR-590-3p perform crucial roles in Lynch syndrome

The aim of the present study was to identify the differentially expressed microRNAs (DEMs) between Lynch syndrome (LS) and the normal colonic (N-C) control samples, predict the target genes (TGs) and analyze the potential functions of the DEMs and TGs. The miRNA expression dataset GSE30454, which included data of 13 LS and 20 N-C tissue samples, was downloaded from the Gene Expression Omnibus. The classical t-test in Linear Models for Microarray Data package was used for DEM identification. TG prediction was performed using 5 databases. The regulatory network of the DEMs and their TGs was constructed using Cytoscape. Functional and pathway enrichment analysis was performed. The transcription factors (TFs), tumor-associated genes (TAG) and tumor suppressor genes (TSGs) were then identified. Three key DEMs hsa-miR-137, hsa-miR-520e, and hsa-miR-590-3p were identified. Hsa-miR-520e and hsa-miR-137 had 4 common TGs, including SNF related kinase, metal-regulatory transcription factor 1 (MTF1), round spermatid basic protein 1 and YTH N6-methyladenosine RNA binding protein 3; hsa-miR-590-3p and hsa-miR-137 had 14 common TGs, including NCK adaptor protein 1 (NCK1), EPH receptor A7, and stress-associated endoplasmic reticulum protein 1; hsa-miR-590-3p and hsa-miR-520e had 12 common TGs, including Krüppel-like factor (KLF) 13, twinfilin actin binding protein 1, and nuclear factor I B. Through the functional and pathway enrichments analysis, MTF1 was involved in regulation of gene expression and metabolic processes, and sequence-specific DNA binding TF activity. KLF13 was involved in regulation of gene expression and regulation of cellular metabolic processes. NCK1 was enriched in the axon guidance pathway. In addition, the functional and pathway enrichment analysis showed certain TGs, such as hypoxia-inducible factor 1α, AKT serine/threonine kinase 2, and rapamycin-insensitive companion of mammalian target of rapamycin, participated in the mTOR signaling pathway. The 3 key DEMs hsa-miR-137, hsa-miR-520e, and hsa-miR-590-3p may have important roles in the process of LS.

miR-1238 inhibits cell proliferation by targeting LHX2 in non-small cell lung cancer

In human cancers, dysregulated expression of LIM-homeobox gene 2 (LHX2) and downregulation of miR-1238 has been reported separately. However, the relationship between them remains unclear. We investigated the functional contribution of miR-1238 to the regulation of LHX2 in non-small cell lung cancer (NSCLC). Here, computational algorithms predicted that the 3′-untranslated region (3′-UTR) of LHX2 is a target of miR-1238. Luciferase assays validated that miR-1238 directly bound to 3′-UTR of LHX2. qRT-PCR and western blot analyses further confirmed that overexpression of miR-1238 mimic in NSCLC A549 and LTEP-α-2 cells inhibited endogenous expression of LHX2 mRNA and protein. Moreover, ectopic expression of miR-1238 in NSCLC A549 and LTEP-α-2 cells suppressed cellular viability and proliferation. siRNA-induced knockdown of LHX2 copied the phenotype of miR-1238 overexpression in NSCLC A549 and LTEP-α-2 cells and LHX2 knockdown inhibited cell cycle. In addition, miR-1238 expression was frequently decreased in human NSCLC tissues and reversely correlated with LHX2 expression, which was increased in NSCLC tissues. Collectively, our findings demonstrate that miR-1238 inhibit the proliferation of NSCLC cells at least partly via repression of LHX2, shedding light on the mechanistic interaction of miR-1238 and LHX2 in NSCLC carcinogenesis. Furthermore, our data suggest that expression of miR-1238 could be a promising therapeutic strategy for NSCLC treatment.

microRNA-192 suppresses the expression of the farnesoid X receptor

Farnesoid X receptor (FXR, NR1H4) plays an important role in the regulation of bile acid homeostasis in liver and intestine and may exert protective effects against certain forms of cancer such as colon carcinoma. However, the role of FXR in cell growth regulation, apoptosis, and carcinogenesis is still controversial. Similar to FXR, microRNA-192 (miR-192) is mainly expressed in the liver and colon and plays an important role in the pathogenesis of colon carcinoma. In this study, we investigated the extent to which FXR is regulated by miR-192. Two in silico-predicted binding sites for miR-192-3p within the NR1H4-3' untranslated region (UTR) were examined in vitro by luciferase reporter assays. Wild-type and mutated forms of the NR1H4-3'UTR were subcloned into a pmirGLO vector and cotransfected into Huh-7 cells with miR-192-3p. To study the effects of miR-192 on the expression of FXR, FXR target genes and cell proliferation, Huh-7 and Caco-2 cells were transfected with miR-192-5p and -3p mimics or antagomirs. In addition, the correlation between FXR and miR-192 expression was studied by linear regression analyses in colonic adenocarcinoma tissue from 27 patients. MiR-192-3p bound specifically to the NR1H4-3'UTR and significantly decreased luciferase activity. Transfection with miR-192 led to significant decreases in NR1H4 mRNA and protein levels as well as the mRNA levels of the FXR-inducible bile acid transporters OSTα-OSTβ and OATP1B3. Significant inverse correlations were detected in colonic adenocarcinoma between NR1H4 mRNA and miR-192-3p expression. In summary, microRNA-192 suppresses the expression of FXR and FXR target genes in vitro and in vivo.

Support Vector Machine Based on microRNA Expression Profiles to Predict Histological Origin of Ampullary Carcinoma: Case Report of a Patient Affected From Adenocarcinoma of the Papilla of Vater With Lynch Syndrome

Adenocarcinomas of Vater's papilla (PVAC) may originate from either the pancreatic duct or the intestinal epithelium. Conflicting data have been reported about the frequency of the 2 anatomical entities and their influence on patients' prognosis. To ascertain the anatomical origin of PVAC in a family member of a Lynch syndrome kindred, we searched for microRNA (miRNA) expression profiles on resected tumor specimens. The support vector machine was trained on our previous miRNAs expression data sets of pancreatic and colorectal tissue samples and used to classify the site of origin of the tumor in our patient. The support vector machine worked by contrasting the profiles of miRNAs in patients with pancreatic ductal and colorectal cancers to that of our patient, which was finally classified as pancreatic ductal adenocarcinoma accordingly to alterations of 55 miRNAs. The PVAC might be originated from ductal epithelium rather than from the intestinal mucosa of the papilla in the case at issue. Alteration of miR-548b-3p, miR-551a, miR-21, miR-92a, miR-let-7i, and miR-181a* emerged as potentially associated with cancer genetic susceptibility in PVAC.